research on gluten free bread

Nutritional Medicine
Food Science
Nutrition and Dietetics

Gluten-Free Breadmaking: Facts, Issues, and Future

In book: Cereal-Based Foodstuffs: The Backbone of Mediterranean Cuisine (pp.247-268)

University of Minnesota Twin Cities

North Dakota State University

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Advances in gluten-free bread technology

Affiliations.

1 Department of Food Technology, Faculty of Applied Sciences, Cape Peninsula University of Technology, Bellville, South Africa [email protected].
2 Biocatalysis and Technical Biology Research Group, Cape Peninsula University of Technology, Bellville, South Africa.
3 Department of Food Technology, Faculty of Applied Sciences, Cape Peninsula University of Technology, Bellville, South Africa.
PMID: 24837594
DOI: 10.1177/1082013214531425

The unattractive appearance of gluten-free bread still remains a challenge in gluten-free breadmaking. In response to this, additives such as dairy products, soya and eggs have been used to improve the quality of gluten-free bread, but with limited success. In recent years, enzymes (transglutaminase and cyclodextrinase) and hydrocolloids (carboxymethylcellulose and hydroxypropylmethylcellulose) have become the main focus for the improvement of gluten-free bread. Transglutaminase has been shown to improve the dough viscoelasticity and decrease crumb hardness (6.84-5.73 N) of the resulting bread. Cyclodextrinase also enhances dough viscoelasticity, resulting in an improvement of 53% in shape index and crumb firmness. Similarly, hydroxypropylmethylcellulose improves gas retention and water absorption of dough and reduces crumb hardening rate of the resulting bread, while carboxymethylcellulose significantly increases dough elasticity (60-70 BU) and bread volume (230-267 cm(3)/100 g bread).

Keywords: Gluten-free products; enzymes; functional properties; hydrocolloids.

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Review Article
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Published: 01 May 2019

Recent practical researches in the development of gluten-free breads

Hiroyuki Yano ORCID: orcid.org/0000-0002-0910-854X 1

npj Science of Food volume 3 , Article number: 7 ( 2019 ) Cite this article

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Wheat bread is consumed globally and has played a critical role in the story of civilization since the development of agriculture. While the aroma and flavor of this staple food continue to delight and satisfy most people, some individuals have a specific allergy to wheat or a genetic disposition to celiac disease. To improve the quality of life of these patients from a dietary standpoint, food-processing researchers have been seeking to develop high-quality gluten-free bread. As the quality of wheat breads depends largely on the viscoelastic properties of gluten, various ingredients have been employed to simulate its effects, such as hydrocolloids, transglutaminase, and proteases. Recent attempts have included the use of redox regulation as well as particle-stabilized foam. In this short review, we introduce the ongoing advancements in the development of gluten-free bread, by our laboratory as well as others, focusing mainly on rice-based breads. The social and scientific contexts of these efforts are also mentioned.

Sustainable plant-based ingredients as wheat flour substitutes in bread making

Strategies to improve wheat for human health

Physico-chemical properties of an innovative gluten-free, low-carbohydrate and high protein-bread enriched with pea protein powder

Introduction.

The aroma emanating from a bread bakery is unmistakably alluring. The flavor and crunchy texture of wheat breads sharpen our appetite and satisfy our basic human cravings for comfort as well as nutrition. Indeed, human beings are so enchanted by bread that it is much more than a “staple food”; it has been called “the staff of life”. Breadmaking has a long and fascinating story. 1 , 2 , 3 , 4 It is generally accepted that breadmaking dates back to the New Stone Age, from 8000 to 10,000 BC, and originated around the Fertile Crescent and consisted of emmer and einkorn wheat grains. 1 At first the grains were consumed as porridge. Then, grains that had been hand-crushed using knocking stones were mixed with water and baked on a heated stone with a cover of hot ash, resulting in an unfermented, flat bread. Later, around 6000 BC, people in southern Mesopotamia started using sourdough, 5 speculated to have been developed accidently in an abandoned mixture of flour and water. This first leavened bread dough, which contained fermentation gas, swelled up in the baking process. In ~3000 BC, the Egyptians improved bread by adding yeast, developing what would become the prototype of modern bread. They dehulled and milled wheat grains using saddle querns, the most ancient type of quern stones, 6 which were later replaced by rotary querns and are used even today. Breadmaking and beer production in Egypt are closely related and are considered evidence of a high degree of civilization. 7 Bread was made not only with flour prepared from raw grains, but sometimes also with malt (germinated grains). Moreover, water with a blend of cooked and uncooked malt was used in brewing. The mixture was strained free of husk before inoculation with yeast.

The precise origin of bread has still not been determined. Recent reports show archaeobotanical evidence that the origins of bread date back to 14,400 years ago. 8 Progress in archaeology will eventually clarify the origin of bread, along with some sense of how bread fits into the larger culture of ancient civilizations. Wheat bread is now one of the most representative food in the world. A unique property of wheat gluten realizes bread with high quality. However, some genetically predisposed people cannot eat wheat bread, because gluten causes harmful reactions to them. In this short review, we will summarize the gluten-dependent swelling mechanism of wheat bread and the recent scientific effort to make bread without gluten.

Modern wheat breadmaking

Simply stated, breadmaking is composed of three steps: mixing/sheeting, fermenting, and baking processes. 9 In the mixing process, wheat flour, water, yeast, sugar, salt, oil, and other components are mixed and kneaded. Here, the ingredients are blended homogeneously and hydrated, resulting in the development of the all-important gluten network. 10 Gluten is made from two major wheat proteins together comprising 85% of wheat endosperm protein: gliadin and glutenin. Kneading of wheat dough promotes the hydrogen bonding and disulfide cross-linking interactions of these proteins, eventually producing a viscoelastic and highly conformational protein network termed “gluten”. 11 Yeast grows fast in the dough, feeding on supplemental sugar, until it consumes all available oxygen. Then, it shifts metabolism from aerobic respiration to anaerobic fermentation. In the subsequent fermentation process, yeast generates fermentation gas, mainly composed of carbon dioxide and other components, such as ethanol:

In wheat dough, the gas is confined in the continuous “gluten matrix”, 12 which is composed of the viscoelastic gluten network and other components, such as starch granules and water (Fig. 1a ). Thus, in the beginning of the fermentation process, many small gas cells are produced throughout the dough, like so many small balloons. As the fermentation proceeds, each small gas cell grows bigger, and the dough rises. In the following baking process, the gas cell inflates further by heat, resulting in the expansion, namely, “oven spring” of the dough. 13 The starch molecules are gelatinized by heat, so that the gluten matrix forming the envelopes of the “balloons” become hardened, thus constructing the stable crumb framework. 14 Concurrently, the crust, or surface of the bread dough, is hardened as well as browned by the Maillard reaction between the sugars and amino acids. 15 Finally, the breadmaking is completed, emitting a fresh aroma. 16

Comparison of the swelling mechanism ( a ) and appearance ( b ) of fermenting wheat dough and additive-free, gluten-free (GF) rice batter

The preparation of ingredients, especially flour, is also a critical step. Wheat grain is composed mainly of three parts: the endosperm, germ, and bran. 17 In the endosperm, which is the major constituent of the polished grain, starch granules are embedded in a protein matrix. 18 Wheat flour is produced by grinding whole-wheat grains or polished ones mechanically. 19 Impact mills, such as hammer mills and pin mills, accomplish particle size reduction by exposing seeds to a set of rotating hammer or pins that fracture the seeds, while roller and stone mills compress the seeds between two hardened surfaces. 20 During the milling of wheat grains, a portion of the starch granules are mechanically damaged. 21 The extent of the damage depends on wheat variety (hard or soft type) as well as milling conditions. In the mixing and fermentation steps of breadmaking, damaged starch accelerates the absorption of water to the starch granules, resulting in the activation of local amylases, leading to the degradation of starch molecules into dextrin and maltose. 22 Consequently, yeast activity and the final bread volume is increased. However, excessive starch damage produces wet or sticky dough and bread with poor quality. Thus, control of flour quality in terms of the starch damage is critical in the milling industry. 23

In other words, intact and damaged starch granules each have their respective role in the making of wheat bread—and, as we will show, in rice-flour breads as well. In the case of wheat dough, intact starch granules constitute the gluten matrix, while damaged ones activate fermentation. Generally, the extent of starch damage in commercially available wheat flours is 10–15%. 19

Social demand for gluten-free food

Gluten intolerance.

While the unique viscoelastic property of gluten realizes wheat bread with high quality, some people choose to or must follow a gluten-free diet. Recent reviews well summarize the background and status quo of gluten-free diets, 24 , 25 so only the outline will be mentioned here. Gluten intolerance includes autoimmune celiac disease (CD), wheat allergy, and non-celiac gluten sensitivity (NCGS). Celiac disease is an autoimmune disorder caused by genetic as well as environmental factors. 26 In CD patients, ingestion of gluten leads to small intestinal damage, typically leading to malabsorption. Its prevalence in the United States and Europe is estimated to reach about 1%. Gluten protein has protease-resistant regions in its structure. 27 Digestion of gluten in the human gastrointestinal tract generates “pathogenic” peptides that occasionally reach the lamina propria, where the peptides are deamidated by local transglutaminase. 28 The modified gluten peptides have a higher affinity to human leukocyte antigen (HLA)–DQ2 as well as HLA–DQ8 molecules, 29 which are present only in the small percentage of people carrying the HLA–DQ2 or the DQ8 haplotype. 30 This bonding results in the presentation of the gluten peptides to T cells, thereby triggering further malignant immune response in those with CD. In addition, tissue transglutaminase cross-links covalently to gliadin molecules. The protein complexes with new epitopes are considered to trigger the primary immune response as well. Antibodies against tissue transglutaminase are characteristic of CD. 31

In contrast, food allergy to wheat is characterized by T helper type 2 (Th2) activation, which can result in immunoglobulin E (IgE) and non-IgE-mediated reactions. 32 The IgE-mediated wheat allergy reactions usually occur immediately after contact of wheat, and are characterized by the occurrence of wheat-specific IgE antibodies in serum. Ingestion of wheat causes food allergy, while inhalation of wheat causes respiratory allergy to genetically predisposed individuals. A food allergy to wheat may cause a life-threatening reaction, such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. 33 In contrast, repetitive exposure to wheat flour may cause baker’s asthma or rhinitis, mostly characterized as occupational allergic diseases. 34 Non-IgE- mediated food allergy reactions to wheat usually occur hours or even days after ingestion of wheat products and are characterized by chronic eosinophilic inflammation of the gastrointestinal tract. 35 There is a variability among reports of wheat allergy prevalence due to the differences in the diagnostic criteria, methodology, age, and geography. 36 The prevalence of wheat allergy is estimated to be 0.9% in the United Kingdom (based on questionnaire response), 37 3.6% in the United States (based on measurement of anti-wheat-specific IgE antibodies), 38 and 0.2% in Japan (based on a combination of questionnaire-based examination, skin prick test, and serum omega-5 gliadin-specific IgE test). 39

Non-celiac gluten sensitivity (NCGS) is a recently proposed, increasingly recognized clinical condition in patients in whom celiac disease and wheat allergy have been ruled out. It is characterized by intestinal and extra-intestinal symptoms triggered by the ingestion of gluten-containing foods. 40 Due to the lack of a reliable biomarker, confirmation of an NCGS diagnosis relies only on a double-blind placebo-controlled (DBPC) gluten challenge. 41

So far, a gluten-free diet is the only safe and effective treatment for the above conditions of gluten intolerance. 32

Gluten-free “lifestylers”

Demand for gluten-free foods is not limited to the gluten-intolerant population. Although it is not clear whether a gluten-free diet is beneficial for one’s health, some gluten-tolerant consumers believe that gluten-free food products are simply healthier. 42 , 43 This can be partly explained by a kind of “health halo” effect, making consumers believe that products with “free-from” label are healthier overall. 44 Besides, some popular books by bestseller authors, athletes, and celebrities have encouraged a gluten-free diet. An online questionnaire survey demonstrated that 41% of non-celiac athletes, including Olympic medalists, follow a gluten-free diet 50–100% of the time, and that adoption of the diet in most cases was not based on a medical rationale and may have been driven by the perception that gluten removal provides health benefits and an ergogenic edge. 45 Approximately 13% of young adults are reported to value gluten-free food; this population is more likely to engage in other healthy dietary behaviors, such as eating breakfast daily and eating more fruits/vegetables while simultaneously pursuing questionable behaviors, such as using diet pills to control weight. 42

A double-blind randomized study found that the supposed health benefit of a gluten-free diet has no evidence base in individuals who do not have celiac disease or irritable bowel syndrome, demonstrating that gluten is unlikely to be the culprit for gastrointestinal symptoms or fatigue in otherwise healthy individuals. 43 Moreover, commercially available gluten-free food products tend to contain ingredients with less diversity and less nutritional quality compared with their gluten-containing counterparts. 46 , 47 Other studies claim that despite recent improvements in the formulation and availability of gluten-free foods, they still are less available and more expensive than gluten-containing versions. 48 They generally have adequate levels of fiber and sugar, but lower levels of protein and higher levels of fat compared with their gluten-containing counterparts. 48 Also, very few gluten-free foods are fortified with micronutrients. 48

The gluten-free products market was valued at USD 4.18 billion in 2017 and this is projected to reach USD 6.47 billion by 2023, at a compound average growth rate of 7.6% during the forecast period. 49 The gluten-free diet has become the mainstream rather than just supporting a niche market.

Developments of gluten-free breads

As mentioned in the previous sections, demand for the development of gluten-free foods is growing. 50 Much of the focus is on bread products, as bread is an important staple food. Rice is considered a suitable substitute for wheat, as it is available worldwide and is less allergenic. So, development of rice-based gluten-free breads is the main topic of this review. It is not easy to make bread without using wheat flour or gluten, as bread’s quality depends on the properties and functionality of gluten. 25 In a wheat flour dough, the gluten matrix, composed mainly of the protein network of gluten, starch granules, and water (Fig. 1a ), encloses the fermentation gas, making small “balloons”. Thus, the dough rises as the fermentation proceeds. On the other hand, hydration of flour from gluten-free cereals, such as rice, results in a runny “batter” rather than viscoelastic “dough” as their proteins do not possess the network-forming properties typically found in gluten. 51 Therefore, the fermentation gases rise to the surface while starch granules and yeast settle. 52 Generally, a gluten-free batter without a thickening agent, such as hydrocolloids, becomes foamy. 53 , 54

Several efforts have been made in the development of gluten-free breads. Typical gluten-free breads contain hydrocolloids (e.g., xanthan gum, guar gum, etc.) which increase the viscosity of the liquid phase, keeping the starch granules, yeast, and gas bubbles suspended in the fermentation process. 52 , 55 The subsequent baking process gelatinizes the starch and hardens around the hydrocolloid membrane surrounding the air bubbles to set the crumb structure. As a surface-active hydrocolloid, hydroxypropyl methylcellulose (HPMC) behaves somewhat differently. It has hydrophobic methyl ester/hydroxypropyl groups in addition to hydrophilic cellulose regions. Thus, HPMC stays at the gas/liquid interface, uniquely stabilizing the bubbles and preventing coalescence. 52 , 56 Moreover, as HPMC is thermoreversible, 57 it also helps harden the bubble membrane in the baking process. 58

Another recent approach includes enzymatic treatment of gluten-free batter. 51 Transglutaminase (EC 2.3.2.13) catalyzes the acyl-transfer reaction between primary amino groups on protein-bound lysine residues and γ-carboxyamide groups on protein-bound glutamine residues. 59 Thus, transglutaminase is capable of introducing covalent cross-links between proteins. 60 The protein cross-linking ability has been shown to transform weak gluten into a strong gluten, with measurable effects on rheological behavior. 61 The addition of transglutaminase, along with HPMC, to a gluten-free rice batter resulted in its improved elastic and viscous behavior, as well as a higher specific volume and softer crumbs in the resulting bread. 62 The improvement in the viscoelastic properties of the rice batter appeared to be associated with the enhanced capability of the rice flour to retain the carbon dioxide produced during proofing. The quantitative decrease of free amino groups of proteins suggested that this improvement was due to the cross-linking of protein, that is, the generation of a gluten substitute, supplementing the role of HPMC in the baking of rice bread. 62 Microstructure analyses of a rice-based bread fortified with skim milk or egg powder using confocal laser-scanning microscopy (CLSM) verified that addition of transglutaminase promoted the formation of a protein network in the gluten-free bread that mimicked the gluten network in wheat breads. 63 The networking efficiency of transglutaminase depends on both the correct protein substrates and the level of enzyme addition. Thus, formation of the appropriate protein network under the right conditions should improve the overall quality of gluten-free bread by enhancing loaf volume and crumb characteristics, as well as appearance.

Improvement of the gas-retaining capability of gluten-free batter using protease, a seemingly paradoxical strategy for cross-linking, is also in progress. Protease has actually been used to weaken wheat dough by cleaving a portion of the gluten network. 64 However, treatment of a brown rice batter with bacterial protease improved bread quality by significantly increasing the specific volume while decreasing crumb hardness and chewiness. 65 CLSM images of the bread crumbs suggested that the gelatinized starch phase was the main structure component in the protease-treated bread. Thus, protease may partially degrade the large macromolecular protein complex embedding starch granules, 66 , 67 resulting in improved continuity of the starch phase as well as better rheological properties of the batter. Treatment of rice batter with a protease from Aspergillus oryzae increased its viscosity and resulted in bread with a high specific volume. Optical microscopic observation of the batter suggested that partially degraded protein, possibly glutelin, and starch granules formed aggregations containing voids. 54 This fine network of interlinked protein‒starch aggregates resulted in gas cell stabilization. 54 Proteases are mainly categorized into four classes based on the catalytic mechanism: metallo, serine, cysteine, and aspartyl proteases. 68 Comparative analyses of the proteases 69 , 70 demonstrated that metallo, serine, and cysteine proteases, but not aspartyl protease, are effective additives for improving the quality of gluten-free rice breads.

Application of the redox regulation

Addition of glutathione, a ubiquitous natural peptide, facilitated the deformation of rice batter, thus increasing its elasticity in the early stages of bread baking and increasing the volume of the resulting bread. 53 , 71 Below, we would like to introduce briefly how glutathione can be used in making gluten-free rice bread. The disulfide bond is a cross-link between two cysteine residues and plays an important role in the structure/function of proteins. 72 Redox regulation, control of reduction/oxidation of the disulfide bonds, as well as phosphorylation are the two major post-translational modifications of proteins. 73 Thioredoxin (Trx), 74 a small 12 -kDa protein, and glutathione, 75 a natural tripeptide, play central roles in the redox-dependent regulatory mechanisms.

Trx reduces the disulfide bond of its target protein specifically. In the reactions below, oxidative status is abbreviated as “OX” and reduced status is abbreviated as “RED”:

Glutathione (GSH) is a tripeptide with a free SH group. Two molecules of glutathione occasionally cross-link with an intermolecular disulfide bond to make “oxidized” glutathione (GSSG). Glutathione’s reaction occasionally entails glutathionylation (GL): 76

Redox regulation has been a key target of Dr. Bob Buchanan’s laboratory, University of California, Berkeley, after he clarified the Trx-dependent regulatory mechanism in photosynthesis. 77 , 78 In the proteomic analyses of plant biochemistry mostly performed by the Berkeley group, 79 , 80 , 81 , 82 we have found that redox regulation occurs in many aspects of plant life and plays critical roles in plant biology: seed germination/maturation, photosynthesis, defense against oxidative stress/pathogens, and others. 83 Then, thinking in the opposite direction, modification of the disulfide bonds in biology, that is, artificial activation of the redox regulatory mechanism, might lead to the production of a new, useful plant. Following this hypothesis, overexpression of Trx in plants was first tried in the starchy endosperm of barley. 84 The transformant germinated earlier than the wild type. Also, enzymes in charge of starch mobilization appeared earlier. As fast germination of barley seeds reduces the production cost and improves the quality of beer, 85 the results suggest the practical utility of Trx transformants. Conversely, underexpression of Trx in white wheat seed has been tried. White wheat has received increasing attention, as it is naturally white and needs no bleaching for uses, such as breadmaking. However, white wheat grains tend to germinate on the spike before harvest. 86 The preharvest sprouting (PHS) reduces the crop yield as well as the quality of the seeds and the flour. Rainfall or high humidity in the grain-filling season leads to PHS, and causes farmers significant financial losses. 87 Suppression of Trx in the starchy endosperm led to improved PHS resistance in the transformants 88 without affecting the crop yield or flour quality. 89

These two findings reported by the Berkeley group are the first discovery that control of Trx expression, that is, artificial redox regulation, affects the physiological processes of plants. Although risk assessment of genetically modified organisms (GMOs) is a critical issue, 90 the characteristics of these and other trial model plants provide the possibility of the industrial application of redox regulation. 91

More recently, we have sought to use this strategy to enable rice batter to confine fermentation gas. Glutathione was added to rice batter in an attempt to transform the intramolecular disulfide bonds of rice proteins into intermolecular disulfide bonds and eventually form a gluten-like network. Both reduced glutathione (GSH) and oxidized glutathione (GSSG) were found to be successful in swelling gluten-free rice batter and bread. 53 , 71 However, contrary to our expectations, analysis of the proteins revealed that no gluten-like protein network was formed. In contrast, microstructure and biochemical analyses suggested that glutathione cleaved the disulfide-linked glutelin polymers embedding the starch granules. The glutelin polymer has been suggested to work as a hindrance to the absorption of water by starch molecules when water is added to a rice flour; 66 glutathione may fray this barrier to make the batter more consistent and viscous, thereby improving its gas-holding capability in the fermentation process, 53 as is the case with protease-treated rice batter. 65 Although the number of its applications in food processing has been limited so far, 91 glutathione appears to be a promising tool for developing food with new properties. Glutathione is usable as a food ingredient in the United States 92 and some east Asian countries. For example, glutathione-based oral dietary supplements have been accorded the status of a Generally Recognized as Safe (GRAS) constituent with Section 201(s) of the Federal Food, Drug, and Cosmetic Act of the US Food and Drug Administration (US-FDA). 93

On the other hand, usage of glutathione for food has some limitations. First, glutathione is not usable as a food in all countries. In Japan, for instance, it is recognized as medicine, and cannot be incorporated as a food additive. 94 Second, GSH-added rice batter has been shown to yield a slight amount of hydrogen sulfide (0.43 ppm) and methyl mercaptan (0.106 ppm) in the headspace gas of the bread. 71 Generation of hydrogen sulfide in heated meat or purified GSH is well known; 95 indeed, a slight amount of hydrogen sulfide contributes to the pleasant aroma of cooked meat 96 and rice. 97 Usage of GSSG in breadmaking instead of GSH significantly reduced the generation of these sulfur compounds, 71 and sensory evaluation demonstrated that the aroma of GSSG-added rice bread was almost equivalent to that of non-added bread. 98 However, we sought to develop rice bread without glutathione or any other additives.

In the process of developing glutathione-added rice bread, we found that the control sample, that is, “non-added bread”, occasionally swelled in fermentation. Although it collapsed mostly in the following baking process, we expected that if optimal conditions could be found, we could make an additive-free, gluten-free rice bread from solely the basic ingredients: rice flour, water, yeast, sugar, salt, and oil.

Additive-free, gluten-free rice bread

The development of additive-free, gluten-free rice bread has taken a trial-and-error rather than a strategic approach. 99 , 100 First, we tried several commercially available rice flours and found that flours with low-starch damage (<5%) were the most suitable. The physical property of the gluten-free rice batter appeared quite different from the familiar viscoelastic wheat dough. It had an appearance and texture of a slurry with low viscosity. So, lots of “cooking tips” have been discerned for the breadmaking process. For example, as rice batter tends to make lumps, we paid attention in the mixing procedure to avoid lumps. Also, the dried yeast needs to be dissolved completely. Generation of bubbles of different sizes due to heterogeneous distribution of dried yeast may result in their coalescence 101 and a sudden shrinkage of the batter in the fermentation process. The breadmaking processes, i.e., mixing of the batter, fermentation and baking, as well as tips for successful making in the respective processes, are mentioned in a later section.

To clarify how the gluten-free batter swells without additives, we sought to investigate the microstructure of the fermenting batter. The fermenting batter appeared like a meringue and was quite different from wheat dough, which is so viscoelastic that its full mass can be lifted with a scoop (Fig. 1b ). As it was not easy to freeze the fragile batter without destroying the delicate structure, a sectioned specimen for microscope observation could not be made. Instead, freshly made batter was sandwiched between a microscope slide and a coverslip and the batter was left at room temperature to ferment there. Optical microscopic observation revealed the microstructure: bubbles covered by starch granules (Fig. 2 ). The structure was entirely different from that of the typical wheat dough, in which gas cells are surrounded by the gluten matrix made by a network of gluten protein and starch granules. 102 In contrast, it had a similar structure to a “particle emulsion” 101 in which rice granules stabilize the interface between oil and water (Fig. 2 ). 103 Thus, it was suggested that the bubble observed in an additive-free, gluten-free rice batter had the structure of a “particle foam” (Figs. 1a , 2 ). 101

Explanatory figure of particle emulsion/foam. Adapted from refs. 99 , 100 . Scale bar: 30 µm. Copyright (2017), with permission from Elsevier

The hypothetical mechanism is illustrated in Fig. 2 . Generally, oil and water do not mix. However, when they are mixed well in the presence of a detergent, microscopic oil droplets covered by detergent molecules disperse throughout water. This is a classic emulsion. Likewise, aeration of water in the presence of detergent results in a foam. A small amount of air is surrounded by a thin film of water, in which detergent molecules stabilize the boundary.

At the beginning of the 20th century, solid particles were found able to adsorb onto the interface between oil and water, and play a similar role to that of detergent molecules. 104 , 105 This is called a “particle-stabilized emulsion” or “particle emulsion”. Starch granules of native rice, maize, wheat, 103 quinoa, 106 high-pressure treated corn starch granules, 107 chemically modified waxy maize and tapioca, 108 as well as rice starch granules 109 have been reported to form particle emulsions. A particle-stabilized foam occurs in the same manner. Particle emulsions/foams have received renewed attention during the past decade, as recent advancement in nanoparticle technology accelerates research trends. 110 , 111 Moreover, such foams have potential applications in a wide variety of industries, including foods, pharmaceuticals, and cosmetics. One of the key advantages of the mechanism for foodstuff applications is that microparticles of biological origin, such as starch granules, cellulose, or protein particles, work as stabilizers. 101 Our report showed for the first time that rice starch granules stabilize particle “foam” in an additive-free, gluten-free rice batter. 99

The breadmaking processes and tips for the successful gluten-free breadmaking from rice flour are summarized in Fig. 3 . In the early stage of fermentation, yeast produces fermentation gas, composed mainly of carbon dioxide and alcohol. Ordinarily, the batter cannot hold the gas and becomes foamy. 53 , 54 However, if rice flour with low-starch damage is used and breadmaking is performed with the right conditions, the fermentation gas is trapped in the batter. 99 Thus, small bubbles appear throughout the batter. The small bubbles are particle foams in which fermentation gas is surrounded by starch granules. As the fermentation proceeds, the fragile bubbles gradually grow bigger, making the whole batter rise. Here, it is critical to keep the temperature stable, as fragile bubbles tend to burst in fluctuating temperatures. In the late stage of fermentation, the swollen bubbles should be heated rapidly to make the starch granules gelatinize, that is, to solidify the bubble walls. The most swollen bubbles are the most fragile, so rapid heating is the key.

Summary of the procedures for making additive-free rice bread and “cooking tips” for each step. Adapted from ref., 100 with permission

The overall process resembles the synthesis of a polyacrylamide hydrogel, in which modified nanoparticles stabilize an air/water (acrylamide solution) emulsion, and the macroporous structure is fixed by thermal-induced polymerization. 112

We have investigated several commercially available rice flours and found that rice flours with less starch damage (<5%) make bread with a higher specific volume. 99 Higher starch damage tends to facilitate greater absorption of water by starch granules. 113 The hydrophobicity/hydrophilicity ratio determines the aptitude of starch granules to form particle foam. 114 Thus, to prevent destabilization of the fragile bubbles in the fermentation process, it is important to maintain the proper hydrophobicity/ hydrophilicity ratio. Our success in making bread using flour with less starch damage, that is, less water absorption, seems consistent with the hypothetical mechanism. In this context, reduction of surface tension by hydrophobic treatment of rice starch granules was successful in making a stable particle emulsion. 108 , 109

From another point of view, if rice starch granules are capable of constituting a particle foam, they should have the ability to mimic the function of detergents, that is, to reduce the surface tension of water. Starch granules with less starch damage (4.7 w/w%) effectively reduced the surface tension of water from 73 to 35 mN/m. In contrast, starch granules with higher starch damage (9.8 w/w%) were not as effective, reducing the surface tension to only 47 mN/m. 99

Starch granules show emulsion-forming ability by stabilizing the water/tetradecane interface. 108 So, similar experiments were conducted using starch granules with low- and high-starch damage (Fig. 4 ). Both starch granules made stable water/tetradecane emulsions (Fig. 4a ). However, the microstructures of the emulsions were somewhat different (Fig. 4b ). Optical microscopic analyses of the emulsions showed that starch granules with less starch damage (LD) covered the oil droplets densely. In contrast, in the case of rice granules with higher starch damage (HD), swollen granules were occasionally seen, and the oil droplets were not covered completely. Thus, rice granules with low-starch damage demonstrated better particle-emulsion-forming ability compared with the high-starch-damage counterparts. This was consistent with the observation that rice starch granules with low-starch damage were suitable for constructing particle foam, that is, to make additive-free rice bread.

a Water/tetradecane emulsions formed by starch granules at different rice flour concentrations. From left to right: control (no flour), addition of rice flour with low-starch damage (20% w/w, 50% w/w), as well as high-starch damage (20% w/w, 50% w/w). b Optical microscopic analyses of the emulsion. Rice flour with low- (LD) and high- (HD) starch damage was compared. Adapted from ref. 99 Scale bar: 100 µm for ×100, and 30 µm for ×400, respectively. Copyright (2017), with permission from Elsevier

All these three observations support the hypothetical particle foam theory. Verification studies are in progress in our lab.

Several approaches in the development of gluten-free bread by our own laboratory and others have been introduced in this review, together with the social and scientific context of these efforts. The research is aimed to improve the quality of life of celiac disease or wheat allergy patients. Better bread quality (flavor, texture, and volume), reduced production cost, and wider availability are all important issues. 115 For example, so far, rice bread lacks the mouth-watering aroma of freshly baked wheat bread. It is not clear whether this is inevitable or whether a better selection of ingredients or an improved breadmaking procedure could lead to improvement of the aroma and flavor of rice bread, such that it becomes comparable with that of wheat bread. Besides, rice breads tend to be sticky compared with wheat bread. Also, gelatinized rice starch tends to retrograde faster, 116 so the bread is prone to become stale and hardened faster, 117 resulting in a shorter shelf life. 118 Using rice varieties with intermediate amylose content and a low water absorption index may give superior crumb properties. 119

Recent wide availability of household breadmaking countertop appliances has prompted our laboratory and others to develop gluten-free bread recipes suitable for these machines. Providing specific ingredients, such as fitted rice flour sold along with the breadmaker, may help consumers experience success in making custom gluten-free bread at home. Improving the machines by incorporating an induction-heating (IH) system may be suitable for making “particle-foam” type rice bread, as an IH system guarantees stable temperature control in fermentation as well as rapid heating in the baking process. 120 Addition of micronutrients and functional food ingredients is also an important theme. Further studies may thus improve the bread quality to be comparable to that of wheat bread and to improve the quality of wheat-sensitive patients’ life through providing a satisfactory diet.

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Acknowledgements

We appreciate Dr. Bob Buchanan and Dr. Peggy Lemaux, University of California, and Dr. Wallace Yokoyama and Dr. James Pan, USDA, for useful discussions. Dr. Shigeru Kuroda is also appreciated for his encouragement throughout this work.

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Yano, H. Recent practical researches in the development of gluten-free breads. npj Sci Food 3 , 7 (2019). https://doi.org/10.1038/s41538-019-0040-1

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Due to the absence of gluten, several challenges arise during gluten-free (GF) bread baking, affecting the mid-and-end-product quality. The main approach to overcome this issue is to combine certain functional ingredients and additives, to partially simulate wheat bread properties. In addition, the optimization of the baking process may contribute to improved product quality. A recent and very promising alternative to conventional baking is the use of ohmic heating (OH). Due to its volumetric and uniform heating principle, crumb development during baking and consequently bread volume is improved, which enhances the overall GF bread quality. Depending on the GF formulation, critical factors such as the electrical conductivity and viscosity of the batter may vary, which have a significant effect on the OH process performance. Therefore, this review attempts to provide a deeper understanding of the functionality of GF bread ingredients and how these may affect critical parameters during the OH processing.

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Introduction

GF products have been gaining interest among scientists, especially in Western countries, where the demand towards these products is increasing. Due to the absence of gluten, significant problems (e.g., poor handling of the batter) arise during the production of GF bread. GF batters are characterized by less viscous, cohesive, and elastic properties, compared to wheat doughs [ 1 ], which consequently lead to poor bread volume, inadequate color, and a crumbling crumb.

To overcome this problem, much research has focused on finding suitable GF formulations and baking conditions to achieve a quality comparable to wheat bread. For this purpose, different approaches have been applied, such as the use of several ingredients or additives, as well as adaptation of the processing conditions, e.g., baking technology. The most recent and promising technological approach is the use of OH. OH, also called electrical resistance heating, is an emerging technology that transforms electrical energy into thermal energy. In food, heating is mainly generated by the conductive movement of ions within the food matrix [ 2 ]. Only a few fundamental studies that successfully used OH for GF bread baking have been reported [ 3 , 4 ]. These have shown a significant improvement in bread volume and crumb properties when using this technology.

Previous studies have identified critical factors that affect OH of food, such as the electrical conductivity, composition, and viscosity of the food [ 5 ]. Nevertheless, fundamental knowledge about the potential role of GF ingredients during ohmic baking and subsequently on the resulting GF bread quality is still scarce. Therefore, this paper intends not only to provide an overview of available studies in this respect, but to elaborate knowledge and understanding of underlying factors that should be considered when using this technology for GF baking. Specifically, it is the aim to understand the effect of GF bread ingredients on the alteration of the electrical conductivity of the food matrix and on the resulting OH process to provide a fundamental theoretical basis for subsequent studies on this topic.

Gluten-free batter and bread properties

In wheat dough, gluten plays an essential role in forming a strong protein network that contributes to the desired viscoelasticity of the dough [ 6 ]. The absence of gluten has a severe impact on the rheological properties of GF batters, leading to a lower viscosity, cohesiveness, and elasticity of the batter [ 1 ]. As GF bread properties strongly rely on starch and flour properties, handling and producing the batter/bread become difficult. Most available research has focused on mimicking the gluten network by applying a wide range of ingredients and additives to improve GF bread characteristics. Starch-rich ingredients, hydrocolloids, emulsifiers, and (isolated) proteins are typical ingredients that are used to provide an optimal batter and bread structure [ 7 ].

The quality of GF bread is mainly influenced by the amount and properties of starches and/or flours, which increase the foam stability of the batter by enhancing its viscosity [ 8 ]. Most GF batters have a higher water content than wheat doughs, which is necessary to ensure proper starch gelatinization upon baking [ 9 ]. The amount of water alters the rheological properties of GF batter by decreasing its solid-like behavior and reducing its viscoelastic properties (decrease of storage (G’) and loss modulus (G”)). This partly influences other rheological properties such as tan δ, consistency and the viscosity of (GF) batters which are important for the final bread quality. An opposite behavior is seen in gluten-containing (wheat) doughs, where the viscoelastic properties are developed without modifying the tan δ ( G ″/ G ′) ; in this case, water has a plasticizing effect on the dough [ 7 ].

The influence and effect of GF batter viscosity on resulting GF bread properties are still not fully understood yet. Previous studies have attempted to mimic the viscoelastic properties of wheat dough by adding functional ingredients to GF batter formulations (see Table 1 ), resulting in different effects. Some studies have reported that higher batter viscosities improve GF bread properties, while other studies found no or opposite effects. Ronda et al. [ 10 ] stated that the specific volume of GF bread was positively correlated with tan δ and negatively correlated with the storage modulus (G′). Meanwhile, Matos and Rosell [ 11 ] found that a higher dough consistency limited dough expansion, resulting in lower bread volume. It seems that a higher viscosity increases gas holding capacity and foam stability, while an exceeding viscosity in GF batters might again limit its ability to expand during proofing. Previous studies have shown that batters with a solid-like behavior generally led to higher GF bread quality, when baked conventionally. However, Waziiroh et al. [ 12 ] highlighted that in the case of ohmic baking, GF batters with liquid-like behavior were more suitable for baking with ohmic heating, as this promoted the ion movement necessary for heating. Overall, research above shows that more profound knowledge and understanding of suitable viscosity ranges for GF batter is important, but further investigations are required in this respect.

Critical parameters during OH

OH is a volumetric heating method that is based on an electrical current passing through a food matrix. This principle results in faster and more uniform heating compared to conventional heating which is based on convection, conduction, and radiation. The advantages of OH also include a shorter processing time and a reduced overall thermal load, which may contribute to better retention of the food quality, e.g., nutritional properties [ 2 ].

Important parameters used during OH are the alternating current frequency, the applied voltage, the heating rate and the temperature to which the food material is heated [ 18 , 19 , 20 ]. Usually, high-frequency ranges above 10 kHz are used to control the corrosion of the electrodes, as reported by several authors [ 19 , 20 , 21 ]. This is explained by Icier [ 22 ] as higher frequencies reduce the cycle time, which simultaneously restricts the electrochemical reactions occurring near the electrode.

According to Palaniappan and Sastry [ 23 ], the most critical property for heating food with OH is its electrical conductivity. Conductivity is a function of temperature, frequency, and product composition, which increases linearly with temperature [ 24 , 25 , 26 ]. Icier [ 22 ] highlighted that pH, food composition, total solid content and viscosity significantly affect the electrical conductivity of liquid food. For solid–liquid foods, particle dimension, density, and the proportion of electrical conductivity of liquid and solid particles are critical factors.

In general, OH depends on the conductive properties of food, especially on the ionic composition/content of the food matrix [ 27 ]. Ionic compounds such as salts and acids that are dissociated in solution into Na + /K + , H + , or Cl − ions enhance the electrical conductivity of the food matrix [ 27 , 28 ]. Fryer et al. [ 25 ] stated that the efficiency of OH increases with salt concentration, as it changes the electrical resistance and therefore, the heating rate. In contrast, non-polar components such as fats, oil, alcohol, and sugar will decrease the electrical conductivity of the food [ 19 , 22 , 27 ]. Halden et al. [ 5 ] affirmed that the melting of fats and the transition of starch, as well as the cell structural changes, could also influence the electrical conductivity of the food matrix.

The total solid content and viscosity of liquid food generally affect the electrical conductivity and the OH rate [ 29 ]. In particular, the dissolved solid content significantly influences the consistency and, therefore, the conductivity [ 30 ]. Li et al. [ 31 ] discovered a negative correlation between the viscosity and conductivity of a starch suspension during starch gelatinization using OH. As the viscosity of the starch suspension increased, the accessibility of unbound water decreased, reducing the mobility of the ions and electrical conductivity simultaneously, which caused a decrease in the heating rate [ 32 , 33 ].

Waziiroh et al. [ 12 ] investigated the correlation between GF batter viscosity and electrical conductivity at 25 °C. Results showed that less viscous GF batters displayed higher electrical conductivities than those made with less water. This was explained by the higher water content of low-viscosity batters, which have a dilution effect on the ions, enhancing ion mobility and therefore reducing electrical resistance. Similarly, Li et al. [ 31 ] studied the electrical conductivity of starch during gelatinization. During heating, the electrical conductivity of starch solution increased. As the starch started to gelatinize, the electrical conductivity reached a plateau. This phenomenon could be explained due to the rapid increase of water-binding during gelatinization, which led to an increased viscosity and reduced the mobility of ions and eventually the electrical conductivity.

The application of OH for baking is still scarce and only few investigations have focused on bread baking (see Table 2 ). To successfully apply OH for baking, the behavior of batter ingredients on critical factors (e.g., conductivity, viscosity) during the heating process needs to be understood. This is especially challenging in bread, as this food matrix progressively transitions from a liquid to a solid-state during heating. First trials have already suggested that rapid and uniform baking enhances GF bread properties [ 4 ]. However, for full exploitation of this OH technology and successful application for GF baking, further detailed research is necessary to gain knowledge about the role and behavior of the batter ingredients to predict its performance during ohmic baking. Past studies have already revealed that starch, protein, salt, water, and yeast, which are major ingredients for GF bread making, significantly alter critical factors of food during OH, which will be used as a basis for discussion in the following chapters.

Effect of gluten-free batter ingredients on the ohmic heating process

Starch and flour are the major components in GF bread. Chaiwanichsiri et al. [ 32 ] suggested that the composition of starch could influence the electrical conductivity of food during OH. Starches contain a small amount of phosphate groups bound to amylopectin, which could serve as free ions and modify the electrical conductivity of starch during gelatinization. According to Wong et al. [ 28 ], potato starch contains significant amounts of phosphorus, more than any other starches, affecting its gelatinization temperature during OH. The phosphorus in potato starch is a negatively charged phosphate ester that along with an electric field, could accelerate starch granule disintegration and water diffusion into the starch granule and decrease the crystalline stability during heating.

To understand how starch-rich ingredients might be affected by the OH process, several properties that affect starch gelatinization and swelling need to be considered, e.g., amylose/amylopectin ratio, the particle size of the starch granule, or the amount of starch damage.

Starch and flour have shown similar pasting properties when heated with OH. However, the proportion of other components (e.g., protein, lipids) which are naturally present in the flours/starches or added to the GF formulation, will significantly affect its pasting properties. In general, lipids and GF proteins will delay the granule swelling, causing less amylose leaching and increasing the gelatinization temperature [ 32 ]. These components may also interact with amylose, delay starch gelatinization, decrease its electrical conductivity, and may increase the OH cooking time. An and King [ 39 ] identified a difference of the gelatinization temperature during OH of starch suspensions depending on their amylose content. The ratio between amylose and amylopectin affects physical properties of starch such as swelling, gelatinization, and retrogradation [ 40 ].

Additionally, He and Hoseney [ 37 ] affirmed that starch gelatinization led to less water availability, decreased ion mobility, increased dough resistance, and, consequently, decreased the electrical conductivity. Martin et al. [ 36 ] stated that the starch granules extracted from ohmic-baked bread were less swollen and not deformed compared with starch granules from conventional-baked bread. This was caused by insufficient water or temperature to melt starch crystallites, leading to an underbaked ohmic bread. Additionally, Bender et al. [ 4 ] highlighted that OH displayed a higher heating rate than conventional heating, resulting in inadequate time and water hydration of starch to swell and solubilize. This phenomenon caused improper starch gelatinization and reduced starch digestibility of ohmic-baked bread. Therefore, adjusting the starch:water ratio, power input, temperature and holding time profile of ohmic baking is considered as a critical condition for assuring suitable processing conditions and end-product quality.

Another important factor that affects electrical conductivity is the starch granule size. Morales-Sánchez et al. [ 33 ] measured the electrical conductivity of different starch suspensions with differing granule sizes, such as rice, corn, and potato starch. Smallest and largest starch granule sizes were seen in rice and potato, respectively, while corn exhibited both small and large granules. It was observed that the electrical conductivity increased with the smallest granule size (rice) and decreased with the largest granule size (potato).

Damaged starch is an important parameter that could influence the electrical conductivity of a food matrix. It represents the number of starch kernels physically broken or fragmented during the milling process. A higher amount of damaged starch caused an increase in viscosity, reduced the movement of ions, thus electrical conductivity and probably heating rate [ 31 ]. Furthermore, the amount of damaged starch was also correlated with water holding capacity (WHC) of a sample, but is not affected by the type of heating method as seen by Da Silva et al. [ 40 ]. These authors found that the WHC of an ohmic heated sample was not different from the conventionally heated starch, concluding that WHC is only affected by the starch properties and not by the heating method.

Starch can be modified by chemical, physical and enzymatic means to improve its functional properties, such as its viscosity, gelling, or pasting properties. Li et al. [ 31 ] reported that the electrical conductivity of native and pre-gelatinized starch differed from each other. Native starch had higher electrical conductivity than pre-gelatinized starch due to its poor solubility and lower water-binding capacity, resulting in lower slurry viscosity, specifically in cold water below 50 ℃. Although there are several studies that investigate the effect of OH on starch granule structure, no studies using modified starches have been carried out yet. Some studies have focused on characterizing the dielectric properties of starch. Dielectric properties are a critical variable in microwave heating that describe the interaction of food with microwave electromagnetic radiation [ 41 , 42 , 43 ]. It is indirectly correlated with electrical conductivity, since both are affected by similar factors such as water content, viscosity, and starch-phase transition. Miller et al. [ 41 ] investigated the dielectric properties of esterified or etherified starches with differing degrees of chemical substitution (acetate, phosphate, quaternary, and tertiary ammonium or octenylsuccinate) and at different starch-to-water ratios. Results showed that the type of chemical modification influenced the dielectric behavior of starch to a greater extent than the starch–water ratio.

Dietary fiber, sugar, and hydrocolloids

Dietary fibers (DF), sugars and hydrocolloids are commonly added to GF bread. These do not only improve the nutritional value of GF bread but also enhance some of its quality parameters like specific volume, crust color, and crumb structure [ 44 ]. The addition of DF may play a role during the OH process, as it will influence the viscosity of the batter due to its water holding properties. This could affect the ion mobility during OH as described before (see “ Critical Parameters during OH ”). Moreover, DF also affects starch gelatinization, limiting starch swelling and therefore raising its gelatinization [ 45 , 46 ]. Until now, there has been no research that characterizes how DF influences the electrical conductivity of food during OH, but several properties (e.g., particle size, structure, and amount of available water) need to be carefully considered, especially in the case of bakery products such as GF bread.

Regarding the effect of sugar, some studies have been carried out to estimate the influence of this component on the OH process. Overall, it is known that sugar decreases the electrical conductivity of the food matrix due to its non-ionic components [ 23 , 47 ]. Makroo et al. [ 48 ] evaluated the effect of sugar on the electrical conductivity of mango puree. The result showed that sugar decreased the electrical conductivity, possibly due to the ability of sugar to bind water and increase the viscosity, limiting the ion mobility. Additionally, Poojitha and Athmaselvi [ 49 ] stated a higher concentration of sugar decreased the electrical conductivity of banana pulp. In general, sugar is widely used in yeast-leavened bakery products as a substrate for yeast. As sugar is added in small amounts (2%) in bakery products, its influence on the electrical conductivity of the batter compared to other ingredients, is questionable.

The most commonly used hydrocolloids in GF baking are hydroxypropyl methylcellulose (HPMC), carboxymethylcellulose (CMC), psyllium, carrageenan, xanthan gum, guar gum, or locust bean gum. The ability of the hydrocolloids to improve the batter properties depends on the type of hydrocolloids used, its interaction with other food components and the process conditions during baking [ 7 ]. Similar to DFs, hydrocolloids will influence the pasting properties, gelatinization, swelling and staling of GF bread [ 9 ]. Ren et al. [ 14 ] investigated the effect of methylcellulose and psyllium on the rheological properties of GF rice batter and bread quality. Apart from the type of hydrocolloid, water level should be well adjusted to obtain desirable rheological GF batter properties. High water addition levels led to low dough stability, overexpansion and weak crumb structure. In contrast, low water addition resulted in high rigidity of dough, excessive air entrapment during mixing, and restrained gas cell expansion. Both conditions showed poor GF bread quality, such as low bread volume, high crumb firmness and non-uniform pore structure.

Only a few investigations have been carried out to study the behavior of hydrocolloids during OH. Marcotte et al. [ 27 ] studied several hydrocolloid solutions, including carrageenan, xanthan, pectin, gelatin, and starch, during ohmic heating. The results showed that the hydrocolloid concentration had a crucial influence on viscosity, and subsequently on electrical conductivity and heating rate. With increasing concentration, the apparent viscosity, electrical conductivity, and heating rate of the solutions increased, resulting in a shorter heating time.

Several factors such as ionic charges, ash content and pH might explain the differences in conductivity between hydrocolloids [ 23 , 27 ], as seen in Table 3 . Marcotte and Trigui [ 50 ]. have evaluated the effect of citric acid addition on the electrical conductivity of hydrocolloids at different pH values but revealed only small differences in electrical conductivity between samples. Overall, hydrocolloid properties like structure, ion charge, and ash content should be considered for ohmic heating, as they significantly affect the heating process.

Proteins are widely used in GF formulations to substitute gluten functionality and improve bread properties, such as crumb structure and volume. This improvement is attributed to its outstanding foaming properties, which stabilize and increase CO 2 retention within the batter [ 6 ]. According to Wilde [ 54 ], two fundamental aspects need to be controlled during foaming: foam formation and foam stability. Foam formation is related to the number and size of gas cells in the batter, while foam stability is related to the preventive action to inhibit coalescence, drainage, and disproportion within gas cells. The formation and stability of a foam mainly rely on the functional properties of the protein, especially on its molecular weight and hydrophobic activity [ 54 ]. Lower molecular weights facilitate the protein diffusion to the bubble interface area, and higher protein hydrophobicity increases foam stability by lowering the surface tension between the phases. Additionally, the electrical charge of the amino acids within the protein significantly affects protein solubility, which later affects foaming, emulsification, and gelling [ 55 ].

The application of protein in GF bread (based on cassava starch, potato starch, or rice flour batters) baked by OH was investigated by Masure et al. [ 3 ]. They found that the addition of egg white protein improved gas cell stabilization, increased loaf volume and contributed to a finer pore structure. However, the effect of these proteins on the OH process was not studied. Moreover, the amount of air stabilized within the foam is decisive during OH, as excessive bubble formation may hinder or even limit its application and decrease the electrical conductivity [ 38 ]. According to Mucchettict et al. [ 56 ], protein has a net charge, but the electrical conductivity of proteinous foods such as milk and whey is mainly due to its soluble salt fraction and water content. The contribution of protein to the electrical conductivity of milk and whey is assumed to be small.

Li et al. [ 57 ] investigated the effect of OH with different voltage on functional properties of soymilk protein. The results showed that protein structure and functional properties in soybean milk greatly changed depending on applied voltage and compared to the traditional heat treatment. However, the authors applied no comparable temperature–time profiles, so it is difficult to conclude on distinct electric field and thermal effects. Alampresse et al. [ 58 ] performed batch and continuous processing of egg protein by OH. Despite the expected changes of egg protein resulting from thermal treatment, samples processed by OH showed an increased apparent viscosity, better foaming capacity and continuous OH treatment resulted in samples with better color retention. The authors emphasized the need to optimize applied temperature–time combinations to develop effective and efficient pasteurization processes with maximized microbial inactivation and minimized detrimental effects on functional properties.

Overall, it can be summarized that proteins significantly influence the foaming properties, viscosity, and electrical conductivity of food matrices. Further investigations to comprehensively explain the role of protein and its foaming properties during OH still need to be conducted.

Fat and emulsifiers

Small amounts of fat in bread can significantly improve bread properties, in particular in GF bread. Most GF bread contain at least twice as much fat than wheat bread. Fat components typically added to bread are shortenings, emulsifiers, or naturally present in the flour/starch ingredient. The main role of fat is to stabilize the gas cells in the GF batter during proofing. Additionally, it serves as a lubricant between the particles in the batter, decreasing resistance towards mixing by lowering batter consistency. During the first stage of baking, fat melts and hinders the water absorption of starch, which in turn delays starch gelatinization and increases the time of bread expansion [ 59 ].

According to Houben et al. [ 60 ], different types of fat influence the GF bread to a different extent, which is mainly attributed to the chemical properties of the fat. Margarine addition (solid fat, higher content of short-chain fatty acids) increases the gas binding capacity. In contrast, vegetable oil (liquid, higher content of long-chain fatty acids) decreases the starch swelling properties resulting in a softer crumb and higher bread volume. Leissner [ 61 ] highlighted that solid fat significantly influences bread volume, while no effect was seen with liquid fat. Moreover, Smith and Johansson [ 62 ] stated that a high amount of solid fat in bread decreased its staling rate. Previous studies related the effect of fat types on bread quality is displayed in Table 4 .

A special consideration has to be given to fat when applying OH, as this nutrient is a non-conductive component, which reduces the electrical conductivity of the food matrix, influencing the heating rate and thus cooking time. The fat concentration of the food matrix is very important, as it might limit the application of OH. According to Bozkurzt and Icier [ 70 ], who studied the influence of fat during OH of meat, fat might also create barriers for the passage of the electrical current. Halden et al. [ 5 ] reported that the electrical conductivity of food was changed after the fat components melted in the course of OH.

Several studies of the effect of fat on OH have been conducted in meat, but until now, there is no available research on the role of fat during ohmic baking. Since the electrical conductivity of the food is affected after the melting of the fat component, the source and properties of fat could play a decisive role. Different chemical compositions of the fat/oil/lipid (fatty acid spectrum: amount and chain length, degree of saturation) or its modification (e.g., fractionated, hydrogenated) define its physical properties like physical state (solid or liquid) or melting point/range, which should be considered, as they may have different effects during ohmic baking.

Emulsifiers are often applied in (GF) bread baking and added in small amounts (0.5–2%). They are responsible for stabilizing batter viscosity, which improve bread volume. They also favor the development of a stable and regular bread crumb and delay bread staling, due to its ability to interact with starch, protein and fat within the bread dough/batter [ 54 ].

From a chemical point of view, emulsifiers are lipids (e.g., lecithin, mono and di-glycerides) and show amphiphilic structures. As lipids, their effect during OH will be similar to lipids, exhibiting very poor electrical conductivities. As some proteins have emulsifying properties too, their effect will probably be defined by their molecular size, charge and its influence on batter viscosity as described before (see “ Fat and emulsifiers ”). One study of de Figueiredo Furtado et al. [ 71 ] investigated the effect of OH on the emulsification activity of lactoferrin. The ohmically heated lactoferrin showed a similar denaturation behavior to conventional heating. Differences were seen in the aggregation of proteins, as smaller protein aggregates were formed during OH. The emulsion displayed less turbidity, indicating less protein aggregation during OH, which directly affected the emulsification properties. Pereira et al. [ 72 ] stated that OH reduces the protein denaturation due to the absence of hot surfaces and less overheating.

Although the effect of emulsifiers on the OH process is mainly defined by its chemical nature, it should also be considered that emulsifiers change the properties of a batter, when using this technology for baking.

In general, breadmaking consists of three basic steps, namely mixing, fermentation, and baking. At the initial mixing stage, ingredients are homogenized and hydrated into a batter, while physically aerating the GF batter. Trapped bubbles will play an important role, as they serve as nuclei for the later proofing stage [ 73 ]. During fermentation, the biological aeration of the batter occurs, which is mainly attributed to the production of CO 2 of the yeast. Yeasts from the species Saccharomyces cerevisiae, also known as Baker’s yeast, are used for this purpose, and are the main leavening agents used in bread. Besides CO 2 production, ethanol and other secondary compounds are metabolized by the yeast, which later affect the volume, structure, flavor, color and shelf life of the final product [ 74 ].

Baker’s yeast, which is commonly added to bread, could potentially affect OH of GF bread in two aspects: by directly influencing the conductivity of the food matrix, or affecting it indirectly through the production of specific yeast metabolites (e.g., CO 2 ) [ 38 , 75 , 76 ].

The first approach has not been widely studied, but some first insights on how yeast cells affect the conductivity of a medium have been reported before. An older study carried out by Johnson and Green [ 75 ] investigated the conductivity of yeast cells in suspension. Their results showed that yeast cells possessed different conductivities, which closely depended on the salt concentration of the media (0.1–1% NaCl) they were exposed to. It was explained that yeast cells could store diffusible salts in their body, which was enhanced with increasing salt concentration. Upon heating, salts were then released from the yeast cells, which altered the electrical resistance of the cells and the surrounding suspension. A more recent study investigated the effect of OH on the structure and permeability of the cell membrane of S. cerevisiae [ 77 ]. It was seen that during OH, intracellular protein materials were translocated out of the cell wall, as the electric field increased from 10 to 20 V/cm. Furthermore, it was observed that the number of proteins exuded from the cell wall of the yeasts was higher with OH than for conventional heating, especially at higher temperatures (55–60 ℃).

Regarding indirect effects, the influence of CO 2 on the electrical conductivity of dough has been reported before, which is a key factor that should be considered when baking with OH. According to Gally et al. [ 38 ], the electrical conductivity of dough was reduced as fermentation time and aeration progressed. This was explained by the significantly poor electrical conductivity of the gas bubbles, which enhanced the electrical resistance of the batter. Also, Kim et al. [ 76 ] monitored the CO 2 production in dough fermentation by measuring its electrical resistance. It was seen that the electrical resistance of the dough rapidly increased in the early stage and gradually increased in the late stage of proofing, which was attributed to the CO 2 production rate of the yeast. So overall, the amount and rate of CO 2 production have a significant effect on the conductivity of the dough. These parameters can be controlled by processing and formulation (e.g. fermentation time, temperature, yeast properties and concentration) as shown by the investigations described below, and could be used to establish a suitable aeration range when using ohmic baking.

As mentioned before, a critical factor that affects fermentation is the yeast strain. According to Birch et al. [ 78 ] strains can lead to different optimal fermentation times, which can vary from 40 to 100 min. This is explained by the different maltase activities in the yeasts, which are influenced by the cultivation method or by the different metabolizations of maltose in the yeast cells. Additionally, Struyf et al. [ 79 ], found that dried instant yeast needed a longer mixing time for rehydrating, while short mixing times were sufficient for compressed yeast to reach maximum fermentation rates. Kim et al. [ 76 ] reported that higher yeast concentrations led to higher CO 2 production in the dough, which could shorten the fermentation time and reduce the electrical resistance of the dough. On the other hand, fermentation time could also be successfully reduced by reaching optimal fermentation temperatures in the batter faster, as some authors report [ 34 , 80 ]. Gally et al. [ 34 ] showed that ohmic-assisted proofing decreased the lag phase of the yeast during the initial fermentation process, resulting in a reduced fermentation time from 58 to 20 min.

Overall, there is not enough information to state whether Baker’s yeast itself could significantly influence the electrical conductivity of a complex food matrix-like GF batter, but it is well-known that metabolites such as CO 2 can significantly alter GF batter properties and especially its electrical conductivity. Since, the biological aeration of a batter can be controlled by several factors, such as yeast properties (strain, type, and concentration) and processing conditions (temperature and fermentation time), these factors could be used as a tool in further studies for tailoring batter aeration, which would suit ohmic baking.

Combining GF bread ingredient functionality with ohmic baking becomes a promising approach to obtain optimal GF bread characteristics. However, understanding the critical factors and the correlation between the ingredients and ohmic baking properties is challenging. This is because GF bread requires complex ingredients to develop its structure during baking. For starch and flour ingredients, the effects are related to their composition, granule size, eventual modification, accompanying compounds (e.g., ash content), and importantly to starch gelatinization occurring with increasing temperature, which majorly changes batter viscosity and porous dough/batter structure. Most polysaccharides and hydrocolloids strongly influence batter viscosity, although the temperature effect differs from starch gelatinization. Proteins are generally an important baking ingredient, additionally, they have a great influence on OH parameters. Electrical conductivity will be affected along with their functional properties (e.g., foam formation and stability, solubility, surface hydrophobicity) and ionic charges. In detail, protein addition aims to provide a targeted dough/batter structure. Thus, their foaming properties, which affect batter viscosity or air incorporation, may highly influence OH parameters, particularly heating rate. Fat and related components are important, as they are poorly conductive themselves and may thus change the electrical conductivity of the resulting batter. Also, their melting behavior during heating has to be considered. Regarding yeast, indirect factors that affect the amount and rate of CO 2 (e.g., fermentation parameters, yeast properties) need to be considered, as they have a direct effect on the electrical conductivity of the batter and therefore on the OH process.

As the bread structure is formed, a complex relationship between ingredients and electrical conductivity take place during baking. To facilitate understanding, an overview on the influence of GF bread ingredients on batter and bread characteristics can be seen in Fig. 1 . Figure 2 also describes the relationship between ingredient functionality and ohmic baking properties. Additionally, a summary of the investigations on the effects of GF bread ingredients on OH properties is presented in Supplementary Table S1.

Overview of the influence of the GF bread ingredients on batter and bread characteristics during ohmic baking

Relation of ingredient functionality and ohmic heating properties with batter and bread properties

Conclusions

OH has been recently used as a novel approach to improve GF bread properties. As GF bread is a complex system composed of several ingredients, this review has highlighted the need for understanding their functionality and role during ohmic baking. Their effect on critical factors of OH, in particular electrical conductivity or heating rate, is one of the main elements to be considered for future adaptation of GF recipe parameters and OH conditions.

Based on the available investigations, the review has revealed that when estimating the effect of any ingredient, two major aspects have to be taken into consideration: (1) the ingredient itself will affect OH parameters due to its chemical composition (e.g., ionic and non-ionic compound), physical properties (e.g., starch damage, particle size, ion charge), and functional properties (e.g., swelling power, foam formation, emulsification ability, solubility, surface hydrophobicity) and (2) structural development of the ingredients during processing (e.g., starch gelatinization, protein denaturation, and foam formation) that lead to changes of viscosity, porosity and density within the dough/batter which could influence OH to a great extent. The main structural development to look at in this respect is dough/batter viscosity, foam formation, stability, or incorporation of air (pores) and induced changes of those structural properties during the ohmic heating process. All these physical parameters are desired dough/batter conditions for an improved final (GF) bread quality, but will alter electrical conductivity and, in most cases, decrease the heating rate. OH parameters need to be adapted to these changing conditions in the course of ohmic baking, requiring a tailored OH processing regime considering different steps with the targeted adjustment of processing parameters.

Overall, this review has identified and gathered fundamental and critical aspects that need to be considered for the application of OH in the field of GF baking. All single ingredients as well as their interaction within the batter and their changing physical properties during the heating phase are factors that need thorough consideration during ohmic baking. Yet, thorough research efforts have to be undertaken for a deeper understanding and more insight into their properties.

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Acknowledgements

This work is a part of a Ph.D. program supported by the Indonesia-Austria Scholarship Programme (IASP), a joint scholarship between the Indonesian Ministry of Education and Culture (KEMDIKBUD) and Austria's Agency for Education and Internationalization (OeAD-GmbH) in corporation with ASEAN European Academic University Network (ASEA-UNINET) (reference number: ICM-2019-13886). Part of this work was also created in course of a research project of the Austrian Competence Centre for Feed and Food Quality, Safety, and Innovation (FFoQSI). The COMET-K1 competence centre FFoQSI is funded by the Austrian federal ministries BMK, BMDW and the Austrian provinces Lower Austria, Upper Austria, and Vienna within the scope of COMET—Competence Centers for Excellent Technologies . The programme COMET is handled by the Austrian Research Promotion Agency FFG. The authors would also like to thank the University of Natural Resources and Life Sciences, Vienna (BOKU) for providing the open access funding.

Open access funding provided by University of Natural Resources and Life Sciences, Vienna (BOKU).

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Conceptualization, EW, DB, and RS; methodology, EW; investigation, EW; formal analysis, EW; resources, EW and DB; validation, EW, DB, and RS; visualization, EW; writing—original draft preparation, EW, DB; writing—review and editing, DB, HJ, and RS. All authors have read and agreed to the published version of the manuscript.

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Waziiroh, E., Schoenlechner, R., Jaeger, H. et al. Understanding gluten-free bread ingredients during ohmic heating: function, effect and potential application for breadmaking. Eur Food Res Technol 248 , 1021–1034 (2022). https://doi.org/10.1007/s00217-021-03942-4

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DOI : https://doi.org/10.1007/s00217-021-03942-4

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ARS scientists have developed a new process to produce gluten-free bread from corn flour that produces higher quality bread that is closer to the texture of conventional bread like those pictured here. Click the image for more information about it.

USDA Scientists Produce Palatable Gluten-Free Bread

A process to produce high-quality, gluten-free bread has been developed by U.S. Department of Agriculture (USDA) scientists in Manhattan, Kan. Millions of Americans affected by celiac disease are unable to digest gluten, a protein in flour from grains such as wheat, barley and rye.

Chemists Scott Bean and Tilman Schober at the Agricultural Research Service (ARS) Grain Quality and Structure Research Unit found that by removing a certain amount of fat from a corn protein called zein, they were able to produce a dough more similar to wheat dough, and free-standing, hearth-type rolls that resemble wheat rolls. ARS is the chief intramural scientific research agency of USDA.

Bean and Schober had some success developing gluten-free pan bread from other grains, but they couldn't make free-standing rolls because the rolls spread out too much. According to Bean, the bread was considered lower in quality than comparable wheat bread. Gluten-free grains include corn, sorghum, and rice.

In previous studies, Bean and Schober found that zein-a readily available byproduct from corn wet milling and fuel-ethanol production-could be used to make dough that was more similar to wheat dough. The dough still didn't meet their standards, though, because it lacked strength, and the rolls produced from it were too flat.

Bean and Schober discovered that removing more of the fat from the zein protein's surface allowed the proteins to stick to each other much like wheat proteins do, giving the zein-based dough the same elastic properties as wheat dough.

According to Bean, while the experiment made more acceptable dough, sorghum may prove to be a better grain to use since it is a gluten-free grain. Bean used corn as an intermediate step toward achieving the ideal in gluten-free breads: a wheat-like dough using non-wheat proteins, resulting in products with a fluffy, light texture.

This research may prove useful for the 2 to 3 million Americans who have celiac disease, a condition in which the human immune system erroneously attacks gluten proteins, causing severe diarrhea and inability to absorb nutrients. Gluten-free palatable rolls from corn, rice and sorghum would be a welcome addition to their diet.

The research results were published in the Journal of Cereal Science and in the November/December 2010 issue of Agricultural Research magazine.

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Bread Experts Share 11 Tips For Making Gluten-Free Sourdough

Gluten-free sourdough bread with ingredients

Very few of the early COVID-19 pandemic-era trends remain. We doubt anyone is still hoarding toilet paper, and there hasn't been much news recently about people still eating horse dewormer as a way to stave off ailments. But one trend that really rose in popularity back in 2020, and has seemingly not ceased, is sourdough baking.

Sourdough refers to baked goods that are made with a sourdough starter . Essentially, it's a culture of wild yeasts and bacteria that ferment and grow on a mixture of flour and water. Caring for a sourdough starter requires daily feeding and removing the sourdough discards . But once you have a steady, well-sustained culture going, you can use it for seemingly everything. Stir it into chewy chocolate chip cookies or stick to classic bread recipes.

The lion's share of sourdough recipes focus on using wheat-based flours, like bread flour, whole wheat, or all-purpose flour. But, believe it or not, it is possible to cultivate a vibrant colony of wild microbiota on a gluten-free flour, too. That way, you can use this recipe for all of your gluten-free favorites, including breads, desserts, and more. We consulted with several baking professionals, including cookbook author Allyson Reedy , co-owner of Bread Bros Amy Jam, and chef Hervé Guillard — the director of education at the Institute of Culinary Education's (ICE) Los Angeles campus — about how to ensure success when making a gluten-free sourdough starter.

1. Start with a whole grain gluten-free flour

The easiest way to whip up a gluten-free sourdough starter is going to be to look for a wheat-analogous product. Some gluten-free flours tend to have more fiber or be a little bit more gritty than white flour, which can alter the texture of your sourdough and the microbes you're trying to attract. Plus, if you consider yourself to be a novice when it comes to gluten-free baking, you may want to use measure-for-measure gluten-free flour to make your sourdough.

Allyson Reedy recommends using a gluten-free flour blend to get your sourdough culture going. "You'll start by mixing a roughly 50/50 blend of the flour and water (use just a smidge more flour than water) in a Mason jar," she explains. "... It can take 10 to 14 days to get a gluten-free starter going, so don't give up! You'll know it's ready when it's doubled in size, has lots of big bubbles, and is nice and fluffy."

One of our favorite measure-for-measure flour blends to work with is from the King Arthur Baking Company. Not only does the brand make a standard gluten-free flour, but it also makes a gluten-free measure-for-measure bread flour . It contains starches and ingredients that will mimic the same elasticity and protein content as traditional wheat flour. "[Flour brands] usually have some basic recipes on their websites as well to get you started. They've done the research so you don't have to," Hervé Guillard explains.

2. Use sorghum flour for a soft bread with moderate sweetness

If you're not familiar with gluten-free baking, sorghum might not resonate with you. But folks who frequently whip up gluten-free muffins and treats may have come across it a time or two. It's a flour that's highly desirable for its smooth texture and balanced mouthfeel; you won't notice too much graininess or nutty flavor when you use it in your recipes.

Sorghum flour is one of Jam's favorites for making gluten-free sourdough with. "I swear by sorghum flour when I'm baking gluten-free products because it not only brings nutrition to the table, but it also adds a mild sweetness and makes the bread softer," she explains. Jam also shares that she uses tapioca and potato starch in tandem with the flour to prevent it from getting too dense.

Jam also underscores the importance of hydration when it comes to making a gluten-free sourdough. "When I work with sorghum flour, I make sure the dough is really moist, going for a water content of about 90-100%," she says. "This is important for building the right structure and keeping the bread just perfect." The hydration ratio refers to the amount of water that you should be using for every 100 grams of flour. So, for 100 grams of sorghum flour, you should be using about 90 to 100 grams of water. In comparison, traditional wheat sourdough caps the hydration anywhere between 65% and 90%.

3. Add psyllium husk to help your sourdough stretch

Mastering gluten-free baking often involves getting an entire arsenal of ingredients ready. While making a traditional sourdough really only requires two ingredients, water and wheat flour, your gluten-free sourdough will require you to play around more with starches and ingredients to give your dough its trademark elasticity. One of those, which Jam cooks with frequently, is psyllium husk.

"Psyllium husk powder is another must-have in our kitchen," Jam shares. "It's a fantastic binder for gluten-free baking and, unlike xanthan gum or guar gum, psyllium husk adds a similar elasticity and structure you'd find in gluten-containing doughs." This is because it produces a gelling effect when combined with other ingredients. In short, this property mimics the same strengthening effect as gluten and will ensure your dough gets the proper rise. Jam also shares an important tip with us about working with psyllium husk. "I always hydrate the psyllium husk in water before it goes into the dough," she explains. "This creates a gel that not only improves the dough's texture, but also makes it a lot easier to handle."

The hydration process can take anywhere from 15 minutes to up to 45, so you'll want to be mindful of this when preparing your dough. Or, you can just opt for using a pre-soaked psyllium gel instead and skip the rehydrating step.

4. Scoop in teff flour for a nutty flavor

Another seed that should be on your gluten-free radar, especially if you're making sourdough bread, is teff. "It adds a unique earthy, nutty flavor that really improves the tanginess of the sourdough," Jam explains. As a general rule of thumb, when substituting white and teff flour , you'll want to stick to a 1-to-1 ratio. The texture of this powder, though, lends itself better to gluten-free batters that don't require the same structure as bread. So, while you can use it as a 1-to-1 replacement for white flour in muffins, you will want to add in some supplementary flours for your bready applications, like buckwheat or a measure-for-measure gluten-free flour.

In terms of sourdough specifically, it's important to note how the teff's texture could alter your finished starter. "Teff can weigh your dough down, so I balance it with lighter flours like white rice flour and allow the dough to ferment a bit longer," Jam explains. "This extra step does wonders for flavor and texture, which makes your gluten-free sourdough come much closer to traditional varieties."

5. Use glutinous rice flour to give your dough some stretchiness

If you don't do a lot of Asian-inspired baking, you may not have ever come across glutinous rice flour. But, if you've ever sampled those delicious frozen ice cream mochi or eaten Thai mango sticky rice , you'll likely know glutinous rice flour better than you'd think. Despite what its name might suggest, glutinous rice flour contains no traces of gluten, which makes it an excellent addition to gluten-free baking.

In particular, Nathan Myhrvold, founder of Modernist Cuisine and the co-author of " Modernist Bread ," adds this rice flour to his sourdough recipe. He told Tasting Table in an interview that he substitutes bread flour in his sourdough with a medley of gluten-free flours, including glutinous rice flour. "Of these ingredients, the glutinous rice flour played a major role in our baking success: When hydrated in doughs and then baked, it retains a particular chewiness reminiscent of gluten," he says.

It's important to note that you can't just load up your sourdough willy-nilly with this flour, as it tends to be quite sweet. Myhrvold adds white and brown rice flour with the glutinous rice flour, along with starches like tapioca and cornstarch. He also swears by some xanthan gum, a common gluten-free baking ingredient. "It absorbs water and makes the mixture more viscous, helping evenly disperse and suspend the starch particles in the crumb and partially substituting for the structure that gluten would normally provide," he explains.

6. Use a fruity ferment to kickstart your sourdough starter

Wait, what is fruit doing in a sourdough recipe? Although it may seem a bit unconventional, you can actually use fruit to kickstart the fermentation in your starter, per Hervé Guillard. He notes that you'll have to dedicate about a week of your time to getting your fruity ferment ready before you can mix it with your gluten-free flour.

Guillard recommends using a ½ pound of organic, skin-on fruit (he prefers dates and fresh peaches) for every 2 cups of filtered water. After the fruit has fermented in the water for a week, he explains how it should be smashed or blended together, then strained to remove the large chunks of fruit. Once you have your fruity ferment, you can mix in your ½ pound of gluten-free flour and get right to work; there's no need to wait the extra time that you would need to wait for a sourdough culture to properly ferment before you bake with it. If you wonder when the right time is to use your ferment, you can always purchase pH test kits. Once it reads a 4, you should be good to go.

There are some fruits that won't work for this technique, including mango, pineapple, kiwi, and papaya. These fruits contain a special enzyme, actinidain, that inhibits protein from correctly developing, which can create issues with the texture and rise of your sourdough.

7. Try buckwheat flour in your gluten-free sourdough

Buckwheat flour is a commonly used ingredient in the gluten-free kitchen. Whole buckwheat has a profoundly earthy flavor that will really elevate your sourdough in the same way that adding teff to it would. Like teff, buckwheat can be quite heavy, so you'll want to use it in tandem with other lighter gluten-free flours, like brown or white rice flour.

You can make your own starter out of buckwheat flour, but be forewarned: The process takes much more time than other gluten-free flours. You won't notice much activity (in the form of bubbles) for the first 10 to 14 days. You may also notice an outcropping of pink liquid in the top of the starter; this may be because of the anthocyanin compounds in the buckwheat. So, you'll have to have a grasp of what to look for before you just assume your starter has gone bad and needs to be thrown out.

The most important thing to know about adding buckwheat to your sourdough is that the finished bread (or whatever baked good you use it for) will be dark in color, so it can shift the entire balance of your bread to something that's more gray and almost tonal in color. It may not look super appetizing, but the nuttiness of the buckwheat flour will make it taste quite delectable.

8. Brown rice flour is a plausible alternative for gluten-based flour

One of the most common types of flour used for gluten-free baking is rice flour. There are two predominant types of flour within this category: white and brown. The white flour is more analogous in flavor to plain white wheat flour, while the brown rice tends to have a nuttier and more complex flavor. Regardless of which type you select, it's important to note that the flour tends to be sticky and not behave like wheat-based flour. So, a large portion of the recipes that use rice flour-based starters will also cut in some gluten-free flour blend later on to help make it a bit lighter and ensure that it behaves. When Hervé Guillard makes his brown rice starter, he uses a mixture of rice flour, sweet potato flour, and plantain flour, along with a bit of xanthan gum.

Like a traditional wheat sourdough, you can start the recipe by mixing equal parts brown rice flour and water, then adding a 50/50 ratio of gluten-free flour and rice flour around week three. This medley will give you the body and texture you're looking for, along with a subtle malty flavor.

9. Swap millet flour into your gluten-free sourdough

Millet flour is another gluten-free flour that you should have on your radar, especially if you're craving something nutty and flavorful. You'll need to look for pearl millet in the store — not pearled millet. The latter still contains its hull, and removing it is just one more step in the sourdough process that you'll want to avoid if you can.

As with other types of flour, like buckwheat and teff, you'll want to avoid making a sourdough that's 100% millet. The grain can be sweet and delectable, but it is quite heavy, and needs to be cut with a lighter flour, like brown rice flour, to ensure the proper rise. You'll also want to make sure your millet seeds are finely ground before you mix them into your starter; otherwise, you won't get the proper consistency. The benefit of using millet flour over buckwheat flour is that it tends to have more activity earlier on; you should start noticing activity within about three days rather than having to wait several weeks. Once your sourdough is bubbling and active, it's time to get the rest of your ingredients and get crackin'.

10. Skip the beer

You shouldn't just be mindful of the gluten in the base of your recipe; you'll also have to consider the gluten content of other ingredients you're baking with. For example, some folks will add beer to their sourdough to imbue it with those perfectly malty, toasty notes and also to promote a browner hue. The beer will also accelerate the yeast activity, since it contains digestible sugars, which can decrease your proofing time significantly.

But not all beers are gluten-free. If you can find a gluten-free beer , like one made from certain types of barley, then by all means throw it into your bread recipe. But otherwise, you may be relegated to reading and scrutinizing labels to ensure that your bread is safe for folks who have celiac or who are gluten-intolerant. The same goes for other ingredients that you add to your sourdough — at any point in making it. Depending on who will be eating the bread, you may need to check the labels to ensure that everything is certified gluten-free before you turn on your oven and get baking.

11. Tips for making gluten-free sourdough

Gluten-free sourdough behaves differently than a wheat-based one and also has differing strength and textural properties — all of which are important to understand before you pull out your ingredients and start cooking. According to Hervé Guillard, "Because gluten-free bread lacks the extensibility of the gluten matrix, it is less forgiving. So, make sure that you feed your starter two days in a row prior to making bread. It should be very bubbly and active to ensure a nice rise." In other words, this is not the time to let your sourdough get super sour in the fridge by not feeding it; you need that activity to get the proper rise. He also shares that because gluten-free bread doesn't have the same structure as wheat, you won't need to knead it as much to shape your loaf.

Guillard also recommends performing an overnight fermentation to max out the flavor in the dough. "Leave the dough covered and undisturbed overnight for a delicious morning bake," he instructs. While this may require that you plan ahead, the flavorful loaf (or sourdough-infused bake) that you get will be well-worth it.

Furthermore, Guillard shares that you should select a baking pan that will help your sourdough rise to its fullest potential. For a classic sandwich bread, he recommends using a tall loaf pan to encourage the bread's rise. Though, for a crusty loaf, he suggests using a Dutch oven, which will trap the steam in and form the perfect crust.

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Compliance and attitudes towards the gluten-free diet in celiac patients in italy: what has changed after a decade.

1. Introduction

2. materials and methods, 2.1. questionnaire, 2.2. statistical analysis, 3.1. descriptive analysis of the celiac disease sample of the latest survey, 3.2. comparison between 2022 and 2011, 4. discussion, 5. conclusions, supplementary materials, author contributions, institutional review board statement, informed consent statement, data availability statement, conflicts of interest.

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Click here to enlarge figure

	Children and Adolescents			Adults		The Elderly	Total Sample
	I (≤10)	II (11–14)	III (15–17)	IV (18–39)	V (40–59)	VI (≥60)	Total Sample
	N = 173	N = 163	N = 141	N = 1216	N = 1451	N = 380	N = 3524
	N (%)
Sex
Female	120 (69)	103 (63)	86 (61)	963 (79)	1091 (75)	273 (72)	2636 (75)
Male	52 (30)	57 (35)	54 (38)	243 (20)	352 (24)	104 (27)	862 (24)
I prefer not to answer	1 (1)	3 (2)	1 (1)	10 (1)	8 (1)	3 (1)	26 (1)
Years after diagnosis
Less than 3 years	85 (49)	43(26)	29 (21)	205 (17)	178 (12)	32 (8)	572 (16)
3–10 years	85 (49)	109 (67)	73 (52)	405 (33)	451 (31)	103 (27)	1226 (35)
More than 10 years	0 (0)	8 (5)	38 (27)	601 (49)	817 (56)	245 (64)	1709 (48)
ND	3 (2)	3 (2)	1 (1)	5 (0)	5 (0)	0 (0)	17 (0)
Are you a member of the Italian Coeliac Association?
Yes	136 (79)	125 (77)	106 (75)	992 (82)	1243(86)	347 (91)	2949 (84)
A relative of mine is a member	25 (14)	23 (14)	17 (12)	47 (4)	33 (2)	9 (29	154 (4)
No	12 (7)	15 (9)	18 (13)	177 (15)	175 (12)	24 (6)	421 (12)
Do you keep yourself informed on celiac disease?
Frequently	104 (60)	93 (57)	83 (59)	539 (44)	721 (50)	200 (53)	1740 (49)
Occasionally	56 (32)	50 (31)	38 (27)	490 (40)	582 (40)	151 (40)	1367 (39)
Rarely	10 (6)	14 (9)	13 (9)	143 (12)	127 (9)	25 (7)	332 (9)
Never	3 (2)	6 (4)	7 (5)	44 (4)	21 (1)	4 (1)	85 (2)
Do you comply with regular checks?
Yes, regularly	163 (94)	150 (92)	128 (91)	751 (62)	827 (57)	215 (57)	2234 (63)
Yes, occasionally	8 (5)	13 (8)	8 (6)	278 (23)	356 (25)	96 (25)	759 (22)
No	2 (1)	0 (0)	5 (4)	187 (15)	268 (18)	69 (18)	531 (15)
Level of education
Primary school diploma/none	173 (100)	156 (96)	39 (28)	2 (0)	3 (0)	3 (1)	376 (11)
Secondary school diploma	0 (0)	7 (4)	99 (70)	94 (8)	93 (6)	34 (9)	327 (9)
High school diploma or equivalent	0 (0)	0 (0)	3 (2)	481 (40)	698 (48)	219 (58)	1401 (40)
University degree or higher	0 (0)	0 (0)	0 (0)	639 (53)	656 (45)	124 (33)	1419 (40)
ND	0 (0)	0 (0)	0 (0)	0 (0)	1 (0)	0 (0)	1 (0)
Main occupation
Student/working student	173 (100)	163 (100)	141 (100)	333 (27)	5 (0)	0 (0)	815 (23)
Unemployed/searching for first job/occasional job	0 (0)	0 (0)	0 (80)	100 (8)	82 (6)	19 (5)	201 (6)
Housewife/househusband	0 (0)	0 (0)	0 (0)	25 (2)	100 (7)	157 (41)	282 (8)
Part-time employment	0 (0)	0 (0)	0 (0)	123 (10)	234 (16)	33 (9)	390 (11)
Full-time employment	0 (0)	0 (0)	0 (0)	635 (52)	1029 (71)	171 (45)	1835 (52)
ND	0 (0)	0 (0)	0 (0)	0 (0)	1 (0)	0 (0)	1 (0)
Marital status
Single	173 (100)	163 (100)	141 (100)	775 (64)	228 (16)	32 (8)	1512 (43)
Life partner	0 (0)	0 (0)	0 (0)	195 (16)	150 (10)	15 (4)	360 (10)
Married	0 (0)	0 (0)	0 (0)	235 (19)	972 (67)	285 (75)	1492 (42)
Divorced/separated/widowed	0 (0)	0 (0)	0 (0)	11 (1)	101 (7)	48 (13)	160 (5)
Do you have any children?
Yes	0 (0)	0 (0)	0 (0)	219 (18)	997 (69)	300 (79)	1516 (43)
No	173 (100)	163 (100)	141 (100)	997 (82)	454 (31)	80 (21)	2008 (57)
Who do you live with?
Alone	0 (0)	0 (0)	0 (0)	100 (8)	126 (9)	57 (15)	283 (8)
With parents/parents and partner	169 (98)	161 (99)	139 (99)	568 (47)	77 (5)	3 (1)	1117 (32)
With partner/spouse only	0 (0)	0 (0)	0 (0)	261 (21)	261 (18)	173 (46)	695 (20)
With children/partner and children/partner, children, and children’s family	0 (0)	0 (0)	0 (0)	220 (18)	952 (66)	133 (35)	1305 (37)
With other relatives	4 (2)	2 (1)	2 (1)	18 (1)	10 (1)	7 (2)	43 (1)
With other cohabitants	0 (0)	0 (0)	0 (0)	49 (4)	25 (2)	7 (2)	81 (2)
Net monthly household income *
EUR >2000	72 (42)	73 (45)	69 (49)	532 (44)	755 (52)	202 (53)	1703 (48)
EUR 1000–2000	41 (24)	31 (19)	25 (18)	479 (39)	486 (33)	139 (37)	1201 (34)
EUR <1000	6 (3)	6 (4)	5 (4)	126 (10)	140 (10)	25 (7)	308 (9)
None	54 (31)	53 (33)	42 (30)	79 (6)	69 (5)	14 (4)	311 (9)
ND	0 (0)	0 (0)	0 (0)	0 (0)	1 (0)	0 (0)	1 (0)
Are there other celiac people in your family?
Yes	33 (19)	38 (23)	33 (23)	311 (26)	494 (34)	109 (29)	1018 (29)
No	140 (81)	125 (77)	108 (77)	905 (74)	957 (66)	271 (71)	2506 (71)

A.	Children and Adolescents			Adults		The Elderly	Total Sample
	I (≤10)	II (11–14)	III (15–17)	IV (18–39)	V (40–59)	VI (≥60)	Total Sample
	N = 173	N = 163	N = 141	N = 1216	N = 1451	N = 380	N = 3524
	N (%)
The gluten-free diet strongly limits my food choices
I disagree/quite disagree	45 (26)	45 (28)	32 (23)	330 (27)	431 (30)	117 (31)	1000 (28)
Neither agree nor disagree	47 (27)	45 (28)	35 (25)	352 (29)	361 (25)	120 (32)	960 (27)
I quite agree/agree	41 (47)	73 (45)	74 (52)	534 (44)	659 (45)	143 (38)	1564 (44)
My food choices are driven by worries about my health status
Never	44 (25)	68 (42)	47 (33)	403 (33)	500 (34)	137 (36)	1199 (34)
Occasionally	63 (36)	51 (31)	44 (31)	391 (32)	494 (34)	132 (35)	1175 (33)
Frequently	41 (24)	26 816)	31 (22)	267 (22)	267 (18)	67 (18)	699 (20)
Always	25 (14)	18 (11)	19 (14)	155 (13)	190 (13)	44 (11)	451 (13)
I think my mood sways my food choices
Never	75 (43) **	78 (48) **	76 (54) **	487 (40)	577 (40)	187 (49)	1480 (42)
Occasionally	68 (39) **	59 (36) **	32 (23) **	345 (28)	444 (31)	119 (31)	1067 (30)
Frequently	21 (12) **	19 (12) **	21 (15) **	253 (21)	287 (20)	52 (14)	653 (18)
Always	9 (5) **	7 (4) **	12 (8) **	131 (11)	147 (10)	22 (6)	324 (9)
In the last year, how often did you restrain your food consumption (e.g.,: I do not find/like the gluten-free alternative)
Never	44 (25)	37 (23)	40 (28)	264 (22) *	322 (22) *	104 (27)	811 (23)
Occasionally	60 (35)	81 (50)	63 (45)	463 (38) *	627 (43) *	161 (42)	1455 (41)
Frequently	53 (31)	30 (18)	30 (21)	406 (33) *	381 (26) *	74 (20)	974 (28)
Always	16 (9)	15 (9)	8 (6)	83 (7) *	121 (8) *	41 (11)	284 (8)
Thinking of food usually worries me
Never	66 (38)	80 (49)	58 (41)	540 (44) *	789 (54) *	230 (60)	1763 (50)
Occasionally	74 (43)	61 (37)	63 (44)	449 (37) *	514 (35) *	121 (32)	1282 (36)
Frequently	28 (16)	17 (10)	13 (9)	164 (14) *	109 (8) *	24 (6)	355 (10)
Always	5 (3)	5 (3)	7 (5)	63 (5) *	39 (3) *	5 (1)	124 (4)
Having to pay attention to what to eat is a problem that worries me for more than an hour a day
Never	69 (40)	97 (60)	82 (58)	684 (56) *	902 (62) *	268 (70)	2102 (60)
Occasionally	76 (44)	39 (24)	42 (30)	327 (27) *	365 (25) *	76 (20)	925 (26)
Frequently	23 (13)	18 (11)	13 (9)	134 (11) *	127 (9) *	25 (7)	340 (10)
Always	5 (3)	9 (6)	4 (3)	71 (6) *	57 (4) *	11 (3)	157 (4)
When I go to a grocery shop, I am confused
Never	84 (51)	106 (65)	91 (64)	810 (67) *	1062 (73) *	312 (82)	2470 (70)
Occasionally	77 (44)	45 (28)	42 (30)	328 (27) *	333 (23) *	60 (16)	885 (25)
Frequently	7 (4)	7 (4)	8 (6)	63 (5) *	46 (3) *	7 (2)	138 (4)
Always	0 (0)	5 (3)	0 (0)	15 (1) *	10 (1) *	1 (0)	31 (1)
I spend a great deal of time thinking about where and what to eat
I disagree/quite disagree	75 (43)	86 (53)	82 (58)	510 (42) *	852 (59) *	269 (71)	1874 (53)
Neither agree nor disagree	42 (24)	36 (21)	29 (21)	243 (20) *	284 (20) *	46 (12)	680 (19)
I quite agree/agree	56 (32)	41(25)	30 (21)	463 (38) *	315 (22) *	65 (17)	970 (28)
I eat at home because I feel safer
I disagree/quite disagree	32 (18)	49 (30)	48 (34)	357 (29)	453 (31)	128 (34)	1067 (30)
Neither agree nor disagree	39 (22)	30 (18)	31 (22)	371 (22)	321 (22)	64 (17)	756 (21)
I quite agree/agree	102 (59)	84 (51)	62 (44)	588 (48)	677 (47)	188 (50)	1701 (48)
It is difficult to find restaurants that offer gluten-free food
I disagree/quite disagree	37 (21)	40 (24)	44 (31)	390 (32) *	469 (32) *	128 (34)	1108 (31)
Neither agree nor disagree	43 (25)	40 (24)	40 (28)	358 (29) *	449 (31) *	130 (34)	1060 (30)
I quite agree/agree	93 (54)	83 (51)	57 (40)	468 (38) *	533 (37) *	123 (32)	1356 (38)
In the last year, how often did you eat in restaurants/pizzerias without asking for information on the served food?
Never	147 (85)	128 (78)	117 (83)	885 (73) *	1107 (76) *	324 (85)	2708 (77)
Occasionally	15 (9)	23 (14)	17 (12)	211 (17) *	246 (17) *	41 (11)	553 (16)
Frequently	8 (5)	5 (3)	7 (5)	74 (6) *	62 (4) *	7 (2)	163 (5)
Always	3 (2)	7 (4)	0 (0)	46 (4) *	36 (2) *	8 (2)	100 (3)
Did you follow a specific diet other than the gluten-free diet?
Yes	13 (8)	5 (3)	11 (8)	208 (17)	272 (19)	88 (23)	597 (17)
No	160 (93)	158 (97)	130 (92)	1008 (83)	1179 (81)	292 (77)	2927 (83)
If you were not a celiac patient, would you have the same food habits?
Yes	119 (69)	119 (73)	103 (73)	933 (77)	1098 (76)	304 (80)	2676 (76)
No	54 (31)	44 (27)	38 (27)	283 (23)	353 (24)	76 (20)	848 (24)
Celiac disease stops me from following another diet (for example, vegan diet) that I followed in the past/I would have followed otherwise
I disagree/quite disagree	142 (82)	134 (82)	118 (84)	980 (81) *	1246 (86) *	315 (83)	2935 (83)
Neither agree nor disagree	22 (13)	14 (9)	12 (8)	101 (8) *	89 (6) *	23 (6)	261 (7)
I quite agree/agree	9 (5)	15 (9)	11 (8)	135 (11) *	116 (8) *	42 (11)	328 (9)




In the last year, how often did you turn down an invitation for fear of eating unsafe food?
Never	39 (23)	56 (34)	43 (31)	358 (29) *	484 (33) *	114 (30)	1094 (31)
Occasionally	84 (49)	58 (36)	63 (45)	495 (41) *	605 (42) *	153 (40)	1458 (41)
Frequently	44 (25)	39 (24)	26 (18)	304 (25) *	281 (19) *	86 (23)	780 (22)
Always	6 (4)	10 (6)	9 (6)	59 (5) *	81 (6) *	27 (7)	192 (5)
I avoid social situations (parties, happy hours, etc.) where I might not control served food
I disagree/quite disagree	69 (40)	82 (50)	63 (45)	575 (47)	618 (43)	123 (32)	1530 (43)
Neither agree nor disagree	50 (29)	47 (29)	37 (26)	262 (22)	338 (23)	75 (20)	809 (23)
I quite agree/agree	54 (31)	34 (21)	41 (29)	379 (31)	495 (34)	182 (48)	1185 (34)
Celiac disease makes my interpersonal relations challenging
I disagree/quite disagree	93 (54)	88 (54)	73 (52)	624 (51)	810 (56)	231 (61)	1919 (54)
Neither agree nor disagree	40 (23)	33 (20)	33 (23)	260 (21)	278 (19)	61 (16)	705 (20)
I quite agree/agree	40 (23)	42 (26)	35 (25)	332 (27)	363 (25)	88 (23)	900 (26)
I go out with friends less frequently since I discovered that I have celiac disease
I disagree/quite disagree	78 (45) **	83 (51) **	88 (62) **	732 (60) *	747 (52) *	198 (52)	1926 (55)
Neither agree nor disagree	46 (27) **	42 (26) **	20 (14) **	210 (17) *	248 (17) *	61 (16)	627 (18)
I quite agree/agree	49 (28) **	38 (23) **	33 (23) **	274 (22) *	456 (31) *	121 (32)	971 (28)
My diet affects the occupation I have chosen/I want
I disagree/quite disagree	134 (78)	111 (68)	98 (70)	945 (78) *	1192 (82) *	309 (81)	2789 (79)
Neither agree nor disagree	26 (15)	32 (20)	19 (14)	126 (10) *	135 (9) *	32 (8)	370 (10)
I quite agree/agree	13 (8)	20 (12)	24 (17)	145 (12) *	124 (8) *	39 (10)	365 (10)

	Children and Adolescents			Adults		The Elderly	Total Sample
	I (≤10)	II (11–14)	III (15–17)	IV (18–39)	V (40–59)	VI (≥60)	Total Sample
	N = 173	N = 163	N = 141	N = 1216	N = 1451	N = 380	N = 3524
	N (%)
How often are you tempted to transgress the gluten-free diet?
I never think about it	89 (51)	74 (45)	66 (47)	652 (54) *	897 (62) *	263 (69)	2041 (58)
Occasionally	74 (43)	77 (47)	67 (48)	489 (40) *	496 (34) *	108 (28)	1311 (37)
Frequently	8 (5)	12 (7)	8 (6)	62 (5) *	47 (3) *	6 (2)	143 (4)
Always	2 (1)	0 (0)	0 (0)	13 (1) *	11 (1) *	3 (1)	29 (1)
In the last month, did you transgress the gluten-free diet?
Yes	11 (6)	14 (9)	8 (6)	132 (11)	136 (9)	25 (7)	326 (9)
No	162 (94)	149 (91)	133 (94)	1084 (89)	1315 (91)	355 (93)	3198 (91)
In the last month, how often did you transgress the gluten-free diet?
Yes, once	8 (5)	9 (6)	6 (4)	76 (6)	85 (6)	18 (5)	202 (6)
Yes, sometimes	3 (2)	5 (3)	2 (1)	43 (4)	43 (3)	7 (2)	103 (3)
Yes, many times	0 (0)	0 (0)	0 (0)	13 (1)	8 (1)	0 (0)	21 (1)
I did not transgress the gluten-free diet in the last month	162 (94)	149 (91)	133 (94)	1084 (89)	1315 (91)	355 (93)	3198 (91)
When you transgressed, how did you feel?
I felt bad because I felt guilty	5 (3)	5 (3)	2 (1)	53 (4)	52 (4)	7 (2)	124 (4)
It was not a problem	4 (2)	7 (4)	4 (3)	72 (6)	69 (5)	14 (4)	170 (5)
I felt good because I was gratified	2 (1)	2 (1)	2 (1)	7 (1)	15 (1)	4 (1)	32 (1)
I did not transgress the gluten-free diet in the last month	162 (94)	149 (91)	133 (94)	1084 (89)	1315 (91)	355 (93)	3198 (91)

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Fiori, F.; Bravo, G.; Neuhold, S.; Bartolone, G.; Pilo, C.; Parpinel, M.; Pellegrini, N. Compliance and Attitudes towards the Gluten-Free Diet in Celiac Patients in Italy: What Has Changed after a Decade? Nutrients 2024 , 16 , 2493. https://doi.org/10.3390/nu16152493

Fiori F, Bravo G, Neuhold S, Bartolone G, Pilo C, Parpinel M, Pellegrini N. Compliance and Attitudes towards the Gluten-Free Diet in Celiac Patients in Italy: What Has Changed after a Decade? Nutrients . 2024; 16(15):2493. https://doi.org/10.3390/nu16152493

Fiori, Federica, Giulia Bravo, Susanna Neuhold, Giovanni Bartolone, Caterina Pilo, Maria Parpinel, and Nicoletta Pellegrini. 2024. "Compliance and Attitudes towards the Gluten-Free Diet in Celiac Patients in Italy: What Has Changed after a Decade?" Nutrients 16, no. 15: 2493. https://doi.org/10.3390/nu16152493

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A Review on the Gluten-Free Diet: Technological and Nutritional Challenges

Dalia el khoury.

1 Department of Family Relations & Applied Nutrition, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; ac.hpleugou@druoflab

Skye Balfour-Ducharme

Iris j. joye.

2 Department of Food Science, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; ac.hpleugou@eyoji

Consumers, food manufacturers and health professionals are uniquely influenced by the growing popularity of the gluten-free diet. Consumer expectations have urged the food industry to continuously adjust and improve the formulations and processing techniques used in gluten-free product manufacturing. Health experts have been interested in the nutritional adequacy of the diet, as well as its effectiveness in managing gluten-related disorders and other conditions. In this review, we aim to provide a clear picture of the current motivations behind the use of gluten-free diets, as well as the technological and nutritional challenges of the diet as a whole. Alternative starches and flours, hydrocolloids, and fiber sources were found to play a complex role in mimicking the functional and sensory effects of gluten in gluten-free products. However, the quality of gluten-free alternatives is often still inferior to the gluten-containing products. Furthermore, the gluten-free diet has demonstrated benefits in managing some gluten-related disorders, though nutritional imbalances have been reported. As there is limited evidence supporting the use of the gluten-free diet beyond its role in managing gluten-related disorders, consumers are urged to be mindful of the sensorial limitations and nutritional inadequacies of the diet despite ongoing strategies to improve them.

1. Introduction

In cereal processing, gluten refers to the combined gliadin (prolamin) and glutenin (glutelin) fraction of wheat [ 1 ]. The gluten protein fraction displays unique structure building properties that are used in food processing. These structure building properties are also reflected in the terminology, as gluten is essentially the Latin translation of “glue” [ 2 ]. Gluten in wheat flour forms a three-dimensional protein network upon proper hydration and mixing. These network-forming properties are utilized in baking applications to create viscoelastic dough matrices. Besides network formation, gluten functionality in food includes water binding and viscosity yielding, which make gluten a widely used food additive [ 3 ].

Gluten is also a nutritional term used to refer to certain cereal prolamins, i.e., the ethanol-soluble proteins of wheat, rye, barley, their cross bred grains, and possibly oats [ 1 , 4 ]. These prolamins are very important in the context of coeliac disease (CD), non-coeliac gluten sensitivity (NCGS), gluten ataxia (GA) and dermatitis herpetiformis (DH). For people suffering from CD, NCGS, GA, and DH, the only effective “treatment” to date consists of eliminating gluten completely and life-long out of their diet. In what follows, general information on gluten-free products and the diet is provided. Challenges when formulating gluten-free products, consumers’ motivations, knowledge and attitudes, as well as the nutritional and therapeutic implications of the gluten-free diet, are also further elaborated on.

2. Gluten-Free Products

Global market data indicate that gluten-free product sales are forecasted to increase by a compound annual growth rate of 10.4% between 2015 to 2020 [ 5 ]. As the clinical application and popularity of the gluten-free diet escalate, consumer demands righteously continue to influence the food market and labelling standards of gluten-free products. In 2013, the European Union Regulation 609/2013 set out rules on compositional and labelling requirements for gluten-free products [ 6 ]. These guidelines ensure that people who are intolerant to gluten are adequately informed of the difference between foods that are naturally free of gluten and foods that are produced, prepared and/or processed in order to reduce their gluten content [ 6 ]. In the same year, the Food and Drug Administration ruled that products labelled “gluten-free” cannot surpass a threshold of 20 parts per million, although the official compliance date was set for 2014 [ 7 ]. This guideline helps gluten-wary customers to navigate the current market and protect themselves from consuming products that may exacerbate their symptoms and/or activate immune-mediated mucosal damage even in the absence of symptoms. The gluten-free diet encompasses food groups that are naturally devoid of gluten, such as fresh fruit, vegetables, seafood, meat, poultry, legumes, nuts, and most dairy products [ 8 ]. However, some of these products may also contain “hidden” gluten. Hence, product labels and ingredient lists need to be carefully reviewed. For the traditional gluten-containing foods, such as bakery products, there is currently a wide variety of gluten-free options available that use gluten-free cereals and pseudocereals, such as rice, corn, quinoa, millet, and amaranth as their base ingredients [ 9 ].

2.1. Gluten Functionality

The unique properties of wheat flour can primarily be ascribed to its gluten fraction. Gluten has unequalled network forming properties, which are important for products that are made with hard wheat varieties, and typically involve an intermediate cohesive dough stage during their production process [ 10 ]. Examples of such products are bread, pasta, and pretzels. Gliadin is the 70% ethanol-soluble protein fraction of wheat flour and is essentially present in wheat grain extracts as monomeric proteins [ 1 ]. Glutenin, on the other hand, is the protein fraction that cannot be extracted with water, diluted salt solutions, and 70% ethanol, and is often referred to as the polymeric gluten [ 1 ]. Both gliadin and glutenin are important for network formation and the quality of the final food product. Although the exact structure and interactions of this protein network are still under debate, it is widely accepted that gliadin has a viscosity-increasing effect, whilst the elastic properties of the network and wheat flour dough predominantly stem from the glutenin fraction [ 1 , 10 ]. For soft wheat products such as cakes and cookies, the gluten network-forming properties are not as crucial, but gluten is believed to nevertheless contribute to final product structure and texture [ 11 , 12 ]. In what follows, focus will be laid on gluten-free bread products as bread is an important staple food and its quality heavily relies on gluten properties and functionality. Hence, bread is one of the more challenging food products when making gluten-free alternatives.

2.2. Gluten Replacement Strategies

Bread baking without gluten essentially removes the most crucial ingredient for product structure and quality. This presents a major challenge to bakers and cereal researchers. In addition, gluten-free products are often consumed by people who have had the opportunity to try and enjoy gluten-containing foods. These consumers, therefore, already have product expectations in terms of texture, structure, flavor and overall quality imprinted. Besides designing gluten-free bread products in such way that they closely mimic the texture of gluten-containing bread products, they also need to have the same sensory profile and shelf life [ 13 ]. One possible strategy that has been identified for matching the volatile flavor of wheat-containing products is combining proline and glucose in the gluten-free product recipe, as these are precursors of the volatile components found in wheat-based bread products [ 14 ]. In what follows, different ingredient and processing strategies will be reviewed, with a focus on texture, structure, and volume of gluten-free bread products. Most of the research done on gluten-free bread formulations focused on the effect of an extra ingredient or a (partial) replacement of one of the base ingredients with a promising other compound. The product against which these new formulations have been tested in terms of quality is almost always the gluten-free product, which does not contain the extra ingredient or the replacement compound. However, as stated above, the real goal of formulating high quality gluten-free products is to achieve the same product characteristics and quality of a regular gluten-containing bread. Therefore, it would be more useful to compare the obtained gluten-free “dough” and bread characteristics with those of an actual similar gluten-containing system.

2.2.1. Ingredients

Imitating the cohesiveness and elasticity of a gluten-containing dough was attempted using a wide range of alternative raw ingredients and/or additives. Gluten-replacing ingredients include starches, gluten-free flours of cereals/pseudocereals, hydrocolloids, and proteins. Minor ingredients that are added to help build and strengthen gluten-free dough and bread structure are enzymes and emulsifiers. Combinations of these are often used to improve the gluten-free product’s rheological characteristics. Some researchers have also invested time and effort in breeding low-gliadin wheat varieties. In general, the recipe alterations for gluten-free bread unfortunately often also lead to an increased product price [ 15 ].

Starch naturally occurs in wheat-based products, as 80% of wheat flour consists of starch. Although starch predominantly acts as a quasi-inert filler material during the initial phases of breadmaking, (part of the) starch gelatinizes upon baking. As a result, starch plays a key role in the structure setting of bread. Hence, the elimination of wheat flour also removes starch from the product recipe. Starches of alternative (gluten-free) sources, such as cassava, tapioca, corn, potato, bean, and rice, have been added to gluten-free recipes [ 16 , 17 , 18 , 19 ]. In recent years, a gluten-free wheat starch was also developed, and has been tested in combination with rice flour and corn starch for the production of gluten-free products [ 20 , 21 ]. In these studies, it was postulated that wheat starch breads were generally better accepted and had an improved loaf volume compared to the corn starch alternative. However, the gluten-freeness of wheat starch preparations is a controversial theme. Starch naturally displays wide variability in terms of morphology, gelatinization behavior, and viscosity yielding. The importance of starch granule morphology was studied using rice starches. In this study, it was found that round starch granules were preferred over polygonal starch structures for product quality [ 22 ]. The underlying reasons for this could, however, expand beyond morphology, and be governed by a rapid gelatinization and good viscosity retention after gelatinization. High viscosity of the batter is essential to build structure in gluten-free food products [ 22 ]. In some cases, the natural variability of starch is not sufficient, and starches are then modified to display a specific characteristic. The use of modified starches has also been investigated in the framework of gluten-free products. Acetylated distarch adipate and hydroxypropyl distarch phosphate were found to increase bread loaf volume, produce a more elastic bread crumb, and result in a slight decrease in hardness and chewiness of the bread crumb [ 23 ].

In addition to starch, gluten-free flours have also been used as base ingredients ( Table 1 ). Examples are flours of pseudocereals, such as amaranth, buckwheat, chia and quinoa, but also cereal flours that do not contain gluten, such as sorghum, rice, corn, teff, and millet. The use of oat flour is controversial, but previous studies have shown that a moderate consumption of oats does not trigger any adverse health effects in most CD patients [ 24 ]. However, the oats that are used need to be certified gluten-free. Oats often become contaminated with gluten-containing cereals during harvest, and the separation of these gluten-containing grains and oats is not that straightforward. Besides cereal and pseudocereal flours, legume (chickpea, pea, carob germ, carob, marama bean, and soy) and chestnut flours have also been successfully used in gluten-free bread applications [ 25 , 26 , 27 , 28 , 29 , 30 ]. The properties of the used gluten-free flours, such as particle size, starch damage, and fiber content, significantly impact the resulting bread characteristics [ 31 ]. This complicates the comparison of the outcomes of different studies on the performance of different ingredients in gluten-free products.

Alternative flours used in gluten-free product formulations with the main quality effects.

Formulation	Main Conclusions	References
Base of corn starch with	Replacement of emulsifier and shortening by the chickpea protein and tiger nut lipids: the combination of both maintains baking characteristics of bread loaves with eliminated shortening and emulsifier.	[ ]
Base of rice flour, potato, tapioca and cassava starch and xanthan gum with	Amaranth and quinoa flour do not affect texture and volume, and final bread loaves are considered ‘moderately acceptable’ in sensory trials.	[ , ]
Base of rice flour and xanthan gum with	Replacement of potato starch with buckwheat and quinoa flour increases bread volume and softens crumb. Amaranth flour only decreases the crumb firmness. None of the three pseudocereal flours adversely affects the sensory properties.	[ ]
Base of corn starch with	Acceptable bread loaves are made with regard to volume and crumb structure.	[ ]
Base of rice flour, maize starch and HPMC with	Bread aroma is enhanced and visual appearance is good. Buckwheat-based sourdough has a bitter taste.	[ ]
blends	Soy flour alters the textural properties and color of the bread.	[ ]
Base of rice flour, shortening, gum blend (xanthan, guar and locust bean gum) and DATEM with partial replacement of the rice flour with	Partial replacement of rice flour with chestnut flour results in lower hardness, increased specific volume, and better color and sensory properties. High chestnut flour recipes had low quality.	[ ]
Base of rice and corn flour, corn starch, HPMC with gradual replacement of rice/corn flour by	Quinoa flour increases loaf volume and yields a more homogeneous crumb structure, whilst not affecting product taste.	[ ]
Base of	Only oats bread is somewhat comparable to wheat bread. All other loaves are of inferior quality in terms of loaf volume, physical crumb texture, shelf life and aroma profile.	[ ]
Base of commercial gluten-free mixtures including corn starch, psyllium fiber, guar gum or corn starch, tapioca starch, potato starch and rice flour, HPMC with partial replacement of the flours by	Dehulled buckwheat flour improved the baking performance of commercial mixtures, whilst puffed buckwheat flour had a clear effect on water availability and the interaction between the matrix biopolymers.	[ ]
Base of corn starch and xanthan gum with	Carob germ flour loaves have the lowest volume, whilst chickpea flour yields the highest volume and the softest crumb.	[ ]
Base of with cassava starch	Marama bean and cassava starch produce strong dough, similar to wheat flour dough that can hold gas in its structure.	[ ]
Base of potato starch and rice flour with	Chia flour does not adversely affect loaf volume and crumb firmness.	[ ]
Base of rice flour, gluten-free wheat starch, albumin, HPMC with	Green plantain flour produces good volume bread loaves, and soft crumb firmness breads having a regular porosity.	[ ]
Base of rice flour and corn starch with	Sensory and nutritional properties are improved with acorn supplementation, whilst the specific volume is decreased, and the crumb hardness is increased.	[ ]
Base of corn starch, HPMC with	Carob germ flour is a good alternative to wheat flour to produce viscoelastic dough and high quality gluten-free bread.	[ ]

DATEM, Diacetyl Tartaric Esters of Monoglycerides; HPMC, hydroxy propyl methyl cellulose.

One of the additives often used as a processing aid and/or quality-improving minor ingredient, is dietary fiber ( Table 2 ). The addition of dietary fiber does not only compensate for the nutritional loss of dietary fiber when excluding wheat flour or whole meal from the product recipe, but it also introduces an ingredient with excellent water-binding, viscosity-increasing, and even gel-forming capacities. As a result, product thickening and texturizing characteristics are re-introduced in the gluten-free process. Examples of dietary fiber that were used in gluten-free products are β-glucan, inulin, oligofructose, linseed mucilage, apple pomace, carob fiber, bamboo fiber, polydextrose, and resistant starch [ 32 , 33 , 34 , 35 , 36 , 37 ]. Fiber structure and molecular weight play a crucial role in gluten-free bread quality [ 38 ]. An alternative way of introducing fiber in the (sourdough) bread recipe was explored by Wolter and colleagues [ 39 ]: exopolysaccharide (essentially a dextran) production by bacteria, such as Weissella cibaria , was found to increase dough strength [ 39 ].

Hydrocolloids used in gluten-free product formulations with the main quality effects.

Formulation	Main Conclusions	References
Zein-starch base with and high β-glucan oat bran	Hydrocolloid and β-glucan improve bread volume and aid zein to more closely resemble gluten in terms of structural and rheological properties.	[ ]
Base of soybean flour and corn starch with and emulsifiers	HPMC increases volume and softness more than xanthan gum, but xanthan gum gives a better crumb structure.	[ ]
Base of teff, buckwheat, corn or rice flour with	Xanthan gum increases the crumb hardness of teff and buckwheat breads, whilst corn breads become softer. HPMC increases loaf volume of teff and corn breads, while xanthan adversely affects the loaf volumes in all different recipes.	[ ]
Base of rice flour, corn starch and sodium caseinate with and oats β-glucan	Except for xanthan, all gums result in a loaf volume increase.	[ ]
Base of potato flour with	Gums yield loaves with higher specific volume and reduced hardness.	[ ]
Base of rice flour, corn starch, soy flour with and transglutaminase	Guar gum increases the specific volume and decreases crumb hardness, while transglutaminase increases crumb hardness but yields a good texture.	[ ]
Base of chestnut and chia flour with	All hydrocolloids increase “dough” elasticity.	[ ]
Base of rice flour, corn starch and sodium caseinate with	Carboxymethyl cellulose increases bread volume and sensorial properties.	[ ]
Base of broken rice berry flour with	Hydrocolloids increase loaf volume, texture, microstructure and sensory properties.	[ ]
Base of tapioca starch, precooked corn flour with	Guar gum and HPMC reduce dough stickiness and soften the crumb.	[ ]
Base of rice and corn flour and corn starch with	Both gums improve crumb color and porosity, cress seed gum triggers the formation of more regular and solid pores.	[ ]

HPMC, hydroxy propyl methyl cellulose.

Hydrocolloids ( Table 3 ) are essentially polymers that display thickening properties through the binding of water. As a result, the viscosity of the gluten-free “dough/batter” is enhanced and gas is better retained in the “dough” matrix, which increases bread loaf volume and improves loaf crumb structure. The most popular hydrocolloids are xanthan gum and hydroxypropyl methyl cellulose (HPMC) [ 40 , 41 , 42 , 43 , 44 ]. Other gums that have been studied are pectin, guar gum, locust bean gum, agarose, tragacanth gum, cress seed gum, and carboxymethyl cellulose [ 26 , 40 , 45 , 46 , 47 , 48 , 49 ].

Fiber (sources) used in gluten-free product formulations with the main quality effects.

Formulation	Main Conclusions	References
Base of corn flour, corn starch, dried eggs and carrageenan with and glucose oxidase	Addition of dietary fiber alters dough cohesion and starch pasting properties. (Glucose oxidase increased the specific loaf volume).	[ ]
Base of corn starch, rice flour, starch and protein, HPMC, locust bean gum, guar gum and alfa-amylase with	Both psyllium and sugar beet fiber improve dough workability. Psyllium fiber is superior in its film forming ability and has an antistaling effect due to higher water binding capacity.	[ ]
Base of rice and corn flour, corn starch, HPMC with	Quinoa bran increases carbon dioxide production, while the gas retention is reduced. Bread volume can be increased without adversely affecting the taste.	[ ]
Base of corn and potato starch, pectin, guar gum with replacement of pectin and guar gum with	Replacement of pectin or guar gum with linseed mucilage improves the sensory acceptance and does not affect texture and bread staling.	[ ]
Base of rice flour, corn starch and HPMC with	Soluble fiber decreases dough consistency, increases bread volume and decreases crumb hardness. The fine insoluble fibers also increase bread volume and decrease the crumb hardness, the coarse insoluble fibers decrease bread volume and increase hardness. In general, soluble fiber increases the structural stability, while insoluble fiber disrupts the structure.	[ ]
Base of rice flour, HPMC with	Low molecular weight β-glucan develops a gel network structure, whilst high molecular weight β-glucan predominantly increases viscosity.	[ ]
Base of white rice, corn and buckwheat flour with	Carob fiber improves volume, color and crumb texture whilst increasing the antioxidant activity of the breads.	[ ]
Base of rice flour, cassava starch, full-fat active soy flour with	Insoluble fiber increases dough firmness and decreases loaf volume, whilst soluble fiber decreases dough firmness.	[ ]
Base of corn and potato starch, guar gum and pectin with	Inulin addition leads to an increased loaf volume and reduces crumb hardness, whilst the internal structure is more polydisperse.	[ ]

Gluten is essentially a protein, and it is logical to explore alternative proteins to make up for the loss of gluten functionality in gluten-free products. In the absence of other structure-forming molecules (such as gums), the structure-forming capacity of proteins was explored. Non-gluten proteins have largely varying effects on dough rheology, as well as final bread characteristics and appearance. In the study by Ziobro and colleagues [ 50 ], the most promising protein in terms of volume increase was albumin, whilst pea and lupine proteins were preferred over soy protein, sensory-wise. Examples of proteins used are legume, egg, dairy, and non-gluten cereal proteins [ 13 , 43 , 51 , 52 , 53 , 54 ]. These alternative proteins/protein sources often also display a better amino acid profile than gluten, which is deficient in essential amino acids such as lysine, and hence, cannot be considered as a “balanced” protein. As a result, these alternative proteins are preferred over gluten, from a nutritional perspective. These proteins also lead to a well-appreciated sensory pallet, as they are involved in Maillard browning reactions, which do not only improve product color but also flavor (compared to, e.g., hydrocolloid-based gluten-free products). However, the increased darkness of the bread may not always be perceived as exceptionally desirable.

Enzymes, as processing aids, are often chosen based on their potential to induce the formation of crosslinks in between the polymers present in the product recipe, thus triggering the formation of a network, similar to what would be the case if gluten was present in the recipe. Examples of studied enzymes are transglutaminase, glucose oxidase, tyrosinase, and laccase [ 55 , 56 , 57 ]. In addition, proteolysis, through the addition of peptidases, has also been explored. These enzymes, similar to what glutathione addition would trigger in bread recipes, lead to depolymerization [ 58 ]. In rice flour, for example, it has been shown that the degradation of the high molecular weight protein fraction of rice is needed to allow small protein aggregates to crosslink through disulfide bonds. This process helps to ensure better rheological properties, improved gas retention during baking, and increased overall product quality [ 59 , 60 ]. Starch hydrolyzing enzymes such as alfa-amylase and amyloglycosidase, were added in some product recipes as well [ 45 ]. One of the reasons for alfa-amylase addition is the in situ production of sugars to sustain yeast activity [ 61 ].

In gluten-free bread products, emulsifiers such as diacetyl tartaric esters of monoglycerides [ 40 ], mono- and diacylglycerol [ 41 ], lecithin [ 62 ] and sodium stearoyl-2-lactylate [ 63 ] are used to establish better interactions between the different ingredients. Emulsifiers may also play a role in stabilization of interfaces such as water/air or water/lipid interfaces. The former interfaces are especially important to the fine crumb structure of gluten-free bread loaves. Some proteins are known to display good interface stabilizing properties as well.

2.2.2. Processing

In addition to rational ingredient and/or additive choice, different processing paths have also been explored to alter the gluten content of gluten-containing flours and improve rheological properties of gluten-free products, particularly gluten-free dough.

Gluten-containing flours have been used in combination with protein hydrolysis strategies or sourdough fermentation to produce gluten-free or so-called ‘gluten-reduced’ bread products. Both the aforementioned technologies are believed to eliminate, or at least significantly reduce, gluten levels in dough. Detoxification of gluten through proteolysis targeting proline and glutamine peptide bonds has been explored recently [ 81 ]. These proteolytic enzymes essentially cleave those peptide bonds that human peptidases cannot affect. The hydrolysis products should be broken down to less than nine amino acids in order not to trigger any reaction in the gastrointestinal tract of people suffering from CD. Similarly, using sprouted grain to formulate products safe for coeliac patients is based on extensive protein hydrolysis, reducing the immune response to the hydrolyzed gluten in the product. However, in the latter case, sprouting conditions need to be tightly controlled and monitored, not only to ensure proper gluten hydrolysis, but also to retain some wheat flour functionality for baking applications. Sourdough fermentation is another strategy which is believed to reduce the level of immunoresponse-triggering gluten. In this framework, the right selection of lactic acid bacteria that display peptidase activity hydrolyzing the appropriate peptide bonds is crucial [ 82 ].

In addition to modifying wheat flour, the gluten-free flours can also be processed in a particular way to change their rheological behavior in dough-like systems. A myriad of different strategies has been explored:

- Corn flour has been milled in various instruments. Different corn varieties were selected to explore the varietal effect and the flour’s physical properties’ impact on its potential to produce high quality gluten-free products [ 83 ].
- Germination of brown rice was studied as a pre-treatment to alter the functionality of brown rice flour in gluten-free bread baking applications [ 84 ]. Rice germination did indeed alter the hydration and pasting properties of the flour. This resulted in increased crumb softness. However, the germination process had to be closely monitored to control the activity of α-amylase.
- Similar to wheat flour-based systems, sourdough fermentation of teff flour products has also been explored [ 68 , 85 ]. The fermentation was shown to have a major impact on the physicochemical properties of teff starch and a more limited effect on the protein fraction. Bread loaves made with this fermented teff flour yielded better gluten-free breads than those produced with unfermented teff flour [ 85 ].
- Phosphorylation of rice flour is another strategy that was studied. The resulting gluten-free breads had a lower hardness and an improved bread volume, crumb appearance, and color [ 86 ].
- Pre-gelatinization of the starch used as a base ingredient has also been attempted and led to a decreased dough elasticity, but a higher resistance to deformation, assuring a better retention of gas in the dough structure. As such, hardness of the product was decreased [ 57 ].
- Heat treatment has been explored to unlock a specific functionality. Buckwheat grains e.g., have been puffed prior to milling and use in gluten-free bread recipes [ 70 ]. Steaming or roasting of soybeans was found to reduce the beany flour of whole soy bread [ 87 ].
- Extrusion of rice flour increased the dough consistency and hydration of rice flour gluten-free bread, while increasing the crumb hardness and lowering the specific volume. However, these bread quality effects can be counteracted by working with flours with coarser particle sizes [ 88 ].
- Particles of whey protein were shown to display elastic and strain hardening characteristics when mixed with starch. Whey protein has been converted to whey protein particles using a cold gelation method prior to being used to produce gluten-free bread [ 89 ]. Van Riemsdijk and colleagues [ 90 ] found that the effect of whey protein particles on bread quality was heavily governed by the amount of disulfide bonds present in the dough (and the particles).

3. Gluten-Free Diet

The origin of the gluten-free diet dates back to 1941, when it made its debut in a report on the dietary treatment of CD by paediatrician and scientist Willem Karl Dicke [ 90 ]. Today, the diet continues to be applied and investigated for a variety of additional health purposes, including the management of NCGS, irritable bowel syndrome (IBS), diabetes, DH, inflammation and obesity.

Research interest in the gluten-free movement, in addition to the clinical and practical uses of the diet, has been growing for many years. In what follows, the current trends, attitudes, and knowledge surrounding the gluten-free diet, as well as its nutritional adequacy, will be covered. Furthermore, the implications of the gluten-free diet on gluten-related conditions, diabetes and other autoimmune diseases, as well as weight management, will be explored.

3.1. Consumers’ Motivations, Knowledge and Attitudes

3.1.1. consumers’ motivations.

Over the past decade, surveys have been conducted to better understand the underlying reasons behind rising trends in gluten-free living [ 91 , 92 , 93 , 94 ]. While the clinical diagnosis of CD influences adherence to the gluten-free diet, data indicate that this disease affects less than 1% of the general population [ 95 ]. Studies show that adverse symptoms, as well as individual efforts to manage them without a clinical diagnosis, impact gluten-avoidance behavior [ 92 , 93 ]. Symptomatic self-management strategies involving a gluten-free diet have been supported by ethnographic research findings as well [ 96 ]. In their field-based study, Copelton and Valle [ 96 ] learned that a self-imposed gluten-free diet was common among individuals presenting with unexplained symptoms for extended periods of time. The anticipated length of time, invasiveness, and frustrations associated with diagnostic tests persuade many of these people to eliminate gluten from their diet on their own [ 96 ].

Expected health benefits of the gluten-free diet also influence dietary decisions. Although beneficial effects of the diet have yet to be demonstrated in healthy individuals [ 97 , 98 ], consumer market survey data demonstrate that 33% and 26% of Canadians and Americans, respectively, believe gluten-free products are healthier [ 99 , 100 ]. These trends are consistent with the findings of another study investigating health beliefs surrounding the gluten-free diet [ 101 ]. In Dunn et al.’s [ 101 ] study, 31% of participants believed that gluten avoidance would promote general health, whilst 37% felt that gluten-free products were healthier than their conventional equivalents. Weight loss was reported as another common motivator for adopting the gluten-free diet, especially among younger adult populations [ 94 ]. However, evidence supporting the effectiveness of a gluten-free diet in weight management is limited, as discussed later.

3.1.2. Consumers’ Knowledge

Mixed rationales for following the gluten-free diet may be reflective of society’s limited understanding of gluten and gluten-free food formulation. In the United States, survey findings from 1012 respondents suggested that, although gluten-awareness is high, a substantial proportion of citizens can neither describe what it is, nor determine product sources of it [ 94 ]. These conclusions have been consistent among smaller studies indicating confusion around gluten-free terms [ 102 ], and issues identifying the gluten content of foods [ 103 ]. Dietitians also express concern for clients with CD who struggle to identify safe options due to their limited knowledge about gluten-free foods [ 104 ].

According to Halmos et al.’s [ 105 ] findings, the greatest challenge may lie in identifying gluten-free ingredients rather than gluten-containing ones. This supports the results of an earlier study by Zarkadas et al. [ 106 ], in which 85% of respondents with CD struggled to determine whether or not certain foods were gluten-free ( n = 2681). Lack of knowledge surrounding the diet has implications for both CD patients and the general public. Leffler et al. [ 107 ] reported that individuals commonly overestimate their adherence to the diet. Recent literature points to the fact that an inadequate understanding of the diet may not only lead to an unintentional ingestion of gluten, but also to an over-restriction of certain foods and poor adherence to the diet overall [ 103 , 105 , 108 ].

Research has also explored the most common sources of information on gluten and gluten-free diets. Questionnaire-derived data indicate that popular sources of gluten-free information include the internet, print media sources, cookbooks, coeliac support groups, and other coeliac patients or individuals on the diet [ 92 , 103 , 109 , 110 ]. Compared to dietitians, family physicians were found to be less likely referred to for gluten-free information [ 103 ], and were rated low or lowest with respect to usefulness [ 109 , 110 ].

3.1.3. Consumers’ Attitudes

Individuals follow the gluten-free diet to varying degrees [ 101 , 103 ]. This may be influenced by the attitudes that people share toward the diet. For example, purchasing gluten-free products may have some negative economic consequences, especially for low-income families [ 104 , 109 , 111 ]. In contrast to their gluten-containing counterparts, gluten-free products are considerably more expensive. In fact, gluten-free items were reported to be approximately 200–500% more expensive than the equivalent standard products, depending on the product and shopping location [ 112 , 113 , 114 , 115 ]. Thus, the affordability and long-term sustainability of the diet continues to spark evaluation.

The inadequate availability of high quality gluten-free items is another burden. Many people report challenges locating such products in local grocery stores [ 106 , 111 ], where their availability varies across shopping venues [ 113 , 115 ]. Individuals with lower socioeconomic status, with limited resources available, or those living in remote cities are certainly at a disadvantage.

Other opinions about the diet focus on the sensory aspects of gluten-free products, as well as the impact it has on many personal and social domains. While consumers may be relatively satisfied with the taste and texture of gluten-free products, continued efforts to improve the palatability of these items are still being urged [ 111 ]. Furthermore, individuals avoiding gluten express a lack of confidence when eating outside of the home [ 106 , 116 ], while many find the length of time involved in the at-home preparation of gluten-free options a nuisance [ 110 ].

3.2. Nutritional Implications

The nutritional adequacy of the gluten-free diet and associated products has always been a concern for consumers, health care professionals, and the industry. While the gluten-free diet is known to alleviate symptoms and promote gastrointestinal healing in patients with gluten-related disorders, long-term adherence to the diet may have concurrent nutritional limitations.

The nutritional profiles of gluten-free products, as well as the dietary intake patterns of individuals on the diet, were assessed in several studies. According to Do Nascimento et al. [ 117 ], gluten-free products share a common composition of raw ingredients, including corn, rice, soy, cassava, and potato. These ingredients replace gluten-containing grains like wheat, rye, and barley in regular products. Overall, gluten-free items are higher in fat, sugar, and sodium compared to regular products, though compositional trends may vary by product type [ 118 ]. Studies have shown that the total fat content of gluten-free breads is at least twice the amount found in their gluten-containing counterparts, contributing to the improved mouthfeel of these products [ 119 , 120 ]. Conversely, many gluten-free pasta products appear to have significantly higher carbohydrate [ 120 ] and sodium contents [ 121 ]. Gluten-free products are generally inferior sources of protein and dietary fiber as well [ 118 , 119 ]. The glycemic index (GI) of gluten-free products varies based on the type and quality of ingredients used, as well as the food-processing procedures performed to manufacture them [ 121 ]. Since gluten-free items are not typically fortified or enriched in the way that many regular products are, they are also generally lower in folate, iron, niacin, thiamin and riboflavin [ 122 , 123 ]. Efforts have been made to improve the formulation of these products without compromising their sensory appeal [ 64 ].

Studies evaluating the dietary intakes of CD patients on a gluten-free diet have reached similar conclusions. According to Barone et al. [ 124 ], CD patients, compared to healthy adults, consume significantly higher quantities of fat and sugar, and lower amounts of fiber on the gluten-free diet. Similar findings were reported by other researchers reporting food-record and questionnaire-based data from adults and children [ 125 , 126 , 127 , 128 ]. However, it is being questioned whether this trend is reflective of overall dietary habits rather than the gluten-free diet alone [ 125 , 129 ]. For example, while CD patients have been shown to share similar intake patterns of cereal-based products in general with the total population, biscuits and crackers are consumed more frequently among individuals with CD [ 129 ]. According to Valitutti et al. [ 129 ], the popularity of these high GI products may also reflect consumer dissatisfaction with the palatability and availability of other gluten-free carbohydrate options, such as bread. Finally, inadequate intakes of iron, folate, calcium, selenium, magnesium, zinc, niacin, thiamine and riboflavin, as well as vitamins A and D were reported in CD patients following a gluten-free diet [ 125 , 126 , 127 , 130 , 131 , 132 ]. While it could be argued that nutrient deficiencies in CD patients can be largely explained by impaired nutrient absorption resulting from CD-associated intestinal damage, Hallert et al. [ 131 ] argue that this may not entirely be the case. Despite 10 years on the diet and evidence of mucosal recovery, the total plasma homocysteine levels of CD patients were still higher than average, reflecting ongoing deficiencies in folate, vitamin B6, and vitamin B12 [ 131 ].

Dietary evaluations performed on CD patients following a gluten-free diet have largely been based on self or proxy-reported data. As always, it is important to acknowledge the potential for participant bias in these types of studies. Nutritional inadequacies associated with gluten-free diets have been shown to vary by gender and dietary experience [ 132 ]. It is therefore, reasonable to assume that gluten-free diet education, health awareness, and other lifestyle factors may influence food choices, and consequently impact study results. Researchers agree that proper follow-up, dietitian collaboration, and nutrition education are important to ensure that those following the diet are not at any additional health risks [ 120 , 130 , 131 ]. Furthermore, a closer look into fortifying or improving the quality of ingredients in gluten-free products continues to be recommended [ 121 , 130 ].

Media and celebrity endorsements of the gluten-free diet for weight loss have stimulated public interest and driven gluten-free market sales [ 133 ]. Empirical evidence confirming the diet’s effects on weight, however, is still unclear. Not only is there limited literature available on the weight-related implications of the diet for the general public, but inconsistent study findings involving CD patient requires further research in this area. To date, the influence of the gluten-free diet on body mass index (BMI), waist circumference, and lipid profiles has been investigated.

It is possible that gluten avoidance might support weight management in healthy individuals, although the evidence is minimal and largely derived from self-reported data [ 134 ]. It has been speculated that losses in weight associated with the gluten-free diet may, instead, be a reflection of health-conscious behaviors [ 134 ], exaggerated reductions in carbohydrates, and low availability of gluten-free food products [ 133 ]. Therefore, contrary to popular belief, there are currently insufficient grounds to verify that gluten elimination results in weight loss for the general public.

Conversely, studies indicate that strong adherence to the gluten-free diet may actually result in weight gain in many CD patients [ 124 , 135 , 136 , 137 , 138 , 139 ]. For those who are underweight at diagnosis, weight gain on the diet is generally more pronounced and favorable [ 136 , 137 , 138 , 139 ]. That said, some evidence suggests that, without adequate dietary counselling, initially overweight and obese CD patients may be at increased long-term health risks on the gluten-free diet [ 135 , 136 , 140 ]. CD patients may also be more susceptible to developing metabolic syndrome in as early as 1 year on the diet [ 140 ]. Nutritional imbalances and shortcomings of gluten-free products, as described in an earlier section, may contribute to some of these changes. On the other hand, a few studies have revealed that a gluten-free diet may help some overweight and obese CD patients lose weight [ 137 , 138 , 139 ]. Earlier diagnosis, perceived mastery of the diet [ 139 ] and counselling by a dietitian [ 138 ] were shown to influence positive weight outcomes on the diet.

Variations between studies may reflect regional or cultural differences in the type and quality of foods consumed on the gluten-free diet, as well as individual exercise practices [ 136 , 138 ]. To gain a better understanding of the actual effects of gluten-free diet on weight and weight management, consistent efforts should be made across studies to monitor the dietary and physical activity habits of participants, as well as their compliance to the gluten-free diet. Additional research is recommended to ensure that healthy and CD individuals are appropriately informed and advised.

4. Gluten-Related Disorders

As previously stated, the gluten-free diet is to date, the only effective treatment to a number of gluten-related disorders, including CD, NCGS, GA, and DH. The role of this diet in alleviating the symptoms of these disorders, in part through the modulation of gut microflora, is discussed in the following sections and summarized in Figure 1 .

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Summary of the effects of the gluten-free diet on the outcomes of gluten-related disorders.

4.1. CD, NCGS, GA, and DH

The introduction of wheat to the human diet prompted a myriad of health conditions derived from the body’s immune response to gluten [ 141 ]. While there is an overlap in their symptomatic presentation, experts have agreed on several distinctions between these gluten-related disorders [ 141 , 142 ]. Wheat can trigger immunologic reactions depending on its route of exposure, by ingestion, inhalation, or skin contact [ 141 ]. When consumed, wheat can act as a food allergen, initiating immunoglobulin E (IgE) or non-IgE mediated reactions [ 143 , 144 ].

CD, DH, and GA are gluten-related autoimmune conditions [ 141 ]. CD is a chronic enteropathy involving a gliadin-specific T-cell response, causing inflammation, villous atrophy, and malabsorption in the small bowel of genetically vulnerable individuals [ 141 , 145 ]. In fact, an association between CD and other gastrointestinal and extraintestinal disorders was reported. DH is a common comorbidity of CD and is often called “coeliac disease of the skin” [ 141 , 145 , 146 ]. It presents as an itchy, blistering rash and is detected by the existence of IgA epidermal transglutaminase antibody complexes in the papillary dermis [ 147 ]. Finally, GA is a condition in which cerebellar damage results from the production of antibodies, following gluten ingestion by susceptible patients [ 141 ]. NCGS, on the other hand, is diagnosed by exclusion criteria; when a reaction to gluten is evident after both a wheat allergy and CD have been ruled out [ 142 , 143 ]. A significant proportion of patients with IBS have a sensitivity to gluten [ 148 ]. Literature indicates that similarities in the clinical presentation of NCGS and IBS generate confusion when evaluating the causes and management options for the manifested symptoms [ 142 , 149 , 150 ].

4.1.1. Management of Symptoms

One way the gluten-free diet can be beneficial to gluten-related disorders is through the management of related symptoms. Researchers agree that strict adherence to the gluten-free diet offers the greatest relief of symptoms for most patients with CD [ 151 , 152 , 153 , 154 , 155 ]. However, symptom recovery rates differ across age and gender [ 151 , 152 , 153 , 154 ]. It is also worth noting that diagnostic delays over 5 years may worsen recovery rates on a gluten-free diet [ 151 ].

Changes in CD-related serum antibody concentrations and mucosal recovery rates, following the gluten-free diet, have also been investigated. Studies provide clear evidence of a decline in tissue-transglutaminase antibodies in CD patients on the diet [ 154 , 156 ], even as early as 3 months following a diagnosis [ 157 ]. Rates of histological normalization on the gluten-free diet are less consistent across studies [ 158 , 159 , 160 , 161 , 162 ]. Longer duration on the diet, however, appears to improve villous recovery [ 160 ]. Adherence to the gluten-free diet, education level, and gluten-free knowledge, as well as age at CD diagnosis, were all shown to influence mucosal recovery [ 158 , 160 , 161 , 163 ].

Although results may take months to years, patients with DH have shown significant improvements and better long-term management of symptoms on a strict gluten-free diet. The diet may also provide a protective effect against the development of lymphoma, which is a potential risk for patients with DH and CD [ 164 ]. According to the literature, the diet can not only help clear skin lesions, but may also heal the small bowel mucosa, decrease IgA and epidermal transglutaminase deposits in the skin, and reduce the need for oral medications in these patients [ 165 , 166 , 167 , 168 ].

Case reports [ 169 , 170 ] and other studies [ 171 , 172 ] indicate that patients with GA may show clinical improvements on a gluten-free diet as well. Neurological benefits, including improved cerebellar function and stabilization of the condition, are influenced by patient adherence to the gluten-free diet [ 172 ]. At least one year on the diet may be required for clear signs of improvement to be detected in GA patients [ 173 ].

The gluten-free diet’s effectiveness in managing NCGS and IBS symptoms is a popular area of debate. For individuals with NCGS, whose symptoms are provoked by gluten, the gluten-free diet is shown to keep the number and severity of their symptoms at bay [ 148 , 173 , 174 , 175 ]. However, randomized, double-blind placebo-controlled challenge studies revealed that the true proportion of gluten-sensitive individuals may be overestimated [ 174 , 176 , 177 ]. Furthermore, although the gluten-free diet was found to provide some relief for patients with diarrhea-dominant IBS [ 178 , 179 ], the roles of α-amylase/trypsin inhibitors and fermented oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) in triggering IBS-type symptoms cannot be ignored [ 180 , 181 , 182 ].

4.1.2. Management of Gut Microflora

Another way the gluten-free diet may benefit some gluten-related disorders is through modulation of gut microflora. The gluten-free diet has been shown to beneficially alter the gut bacterial composition and function in individuals with CD [ 183 , 184 ]. The low polysaccharide content of the gluten-free diet could help explain some of the changes observed in the microbiota [ 185 ]. Intestinal healing on the diet may also help support the growth of different bacterial species [ 183 ]. However, findings are still inconsistent. In adults with CD, Nistal et al. [ 183 ] found that adult patients on the diet began to show some changes similar to the microbial community patterns of healthy adults, but that differences in the richness and presence of unknown bacterial communities still existed. In child CD patients, more than 1 year on the diet seems to be needed to restore normal functions of the gut microflora [ 184 ]. Differences in the reported benefits also exist between the gut microbial composition of symptomatic and asymptomatic CD patients on a gluten-free diet [ 186 ].

Additional studies are still needed for a consensus to be reached. Research of this kind is limited and mostly restricted to small sample sizes. There is also inconsistency in the target age groups across studies, as well as the duration and adequacy of gluten-free dietary adherence. The effects of confounding genetic and other environmental factors on the gut microbiome must also be considered.

4.2. Other Disorders Closely Linked to CD

An association was described between type 1 diabetes (T1D) and CD, with a 1–16% prevalence of CD found in T1D cases [ 187 ]. In addition to T1D, patients with CD are more susceptible to developing autoimmune diseases including autoimmune thyroiditis, psoriasis, rheumatoid arthritis, Sjögren’s syndrome, DH, and Addison’s disease [ 188 , 189 ].

Both genetic and environmental elements are known to influence the development of T1D, and researchers suspect that dietary gluten may be one contributing factor [ 190 ]. Human studies have produced less conclusive results than pre-clinical studies and additional research is still needed. Variations in the clinical backgrounds, age groups, and dietary compliance of subjects, as well as the lack of controls and small sample sizes across studies might explain the inconsistencies. Owing to the association between T1D and CD, researchers have also investigated the gluten-free diet’s impact on glycemic control in patients with both autoimmune diseases. The gluten-free diet reduced severe hypoglycemia in children with T1D and CD, over the short term [ 191 ]. Although the level of clinical significance varies between studies, HbA1c levels were also found to improve in children with T1D and CD following a gluten-free diet intervention [ 192 , 193 ]. However, other studies found no significant improvement in metabolic control in T1D patients with CD following a gluten-free diet [ 194 , 195 , 196 ]. Furthermore, the high GI of many gluten-free products could put ill-informed T1D patients at risk of a loss of glycemic control [ 197 ].

4.2.2. Other Autoimmune Diseases

The role of the gluten-free diet in reducing the risk of comorbidities of autoimmune diseases in CD patients remains unclear. In 1999, Ventura et al. proposed that the incidence of other autoimmune diseases in patients with CD may be linked to prolonged exposure to gluten. Since then, other studies have been conducted to further explore the association between gluten exposure in CD patients and the development of these disorders [ 188 , 198 , 199 , 200 ]. Three of the studies revealed that the risk for developing other autoimmune diseases does not appear to be significantly impacted by the duration of gluten exposure in CD patients [ 188 , 198 , 199 ]. Cosnes et al. [ 200 ], on the other hand, reported a possible protective effect of the gluten-free diet. As many of these studies are based on retrospective data [ 198 , 199 , 200 ], prospective research in this area is advised.

5. Conclusions

The replacement of gluten as a vital ingredient in numerous food products is not straightforward. Different ingredients and processing techniques have been investigated to date. However, the quality of gluten-free products is often not comparable to gluten-containing products. More effort should be devoted to a more rational approach which uses the gluten-containing product as the golden standard.

The motivation to adopt a gluten-free lifestyle goes beyond its original application for CD management. Perceived health benefits and relief of adverse symptoms on the diet influence individual decisions to abstain from gluten. Even so, confusion surrounding gluten and gluten-free options, as well as the high cost and low availability of gluten-free products, can be burdensome for many people. For others, drawbacks of the gluten-free diet may be small in comparison to the clinical improvements made on the diet. Despite media claims, there is also limited evidence confirming the diet’s effectiveness in weight loss for the general public. Furthermore, the reported weight gain in CD patients on the diet may not always be favorable, particularly among previously overweight and obese individuals. However, to date, no beneficial effects from a gluten-free diet have been shown in healthy individuals. Most importantly, individuals choosing to follow a gluten-free diet should take caution of the macronutrient and micronutrient inadequacies of the diet. Overall, it is generally recommended that dietary education and counselling be offered to support gluten-free dieters.

Author Contributions

Writing-Original Draft Preparation, D.E.K., S.B., I.J.J.; Writing-Review & Editing, D.E.K., S.B., I.J.J.; and Supervision, D.E.K., I.J.J.

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

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Personalization.

What Bread is Best for Type 2 Diabetes?

One of the most common sources of carbohydrates in the average person’s diet is bread. Pre-sliced, whole grain, tortillas, naan, pita bread, bagels… there are literally hundreds of types of bread to choose from. But what do you do when you’re living a low-carb lifestyle? What bread is good for people with diabetes? What is a good substitute bread for people with diabetes if you’re cutting bread out completely? What bread is lowest in sugar? Let’s take a look at some of the good substitute bread options available on store shelves, and a few tasty options you can cook up in your own kitchen.

Can I eat bread if I have type 2 diabetes?

At Virta , our stance is to generally avoid traditional bread and grain-based products that are high in carbs. These foods trigger an insulin response from your body and make blood sugar levels more difficult to control, especially for people with diabetes. There are a number of good bread substitutes that can satisfy your craving without spiking your blood sugar.

What is a good substitute for bread with diabetes?

So, what is a good substitute for bread with diabetes? For starters, this skillet bread with cheese is a good substitute bread option. Packed with cheddar cheese, and using substitutes of almond flour and flaxseed meal in place of traditional flour gives this cheesy bread all the chew and flavor of traditional bread without the bump in blood sugar.

You also might wonder, is sourdough a good bread for people with diabetes? Sadly, no, but if you’re craving dinner rolls, these easy-to-prepare low-carb dinner rolls with garlic and parmesan can scratch your bread itch. Spread the butter on and enjoy the garlic-y goodness, because coconut flour and psyllium powder again take the place of traditional flour to make this a good bread substitute for people with diabetes

Need something to take the place of waffles or pancakes for your weekend breakfast or brunch? Chaffles . Cheese waffles. Sounds like a match made in heaven, right? Only three ingredients, and almond flour takes the place of traditional flour to give you a low-carb breakfast go-to. Top with full-fat yogurt and berries, butter, or sugar-free whipped cream.

How to shop for diabetes-friendly bread

While some solid low-carb and bread substitutes are available at the grocery store, it’s important to remember that not every low-carb product is right for every person. For example, low net carbs doesn’t always mean low total carbs , and if you have high blood sugar those options may not be a great choice.

That said, low-carb tortillas, keto bread, and almond, coconut, flaxseed or chia seed breads can be good substitute breads for people with diabetes. Some of the best store bought bread substitutes for people with diabetes can actually be found in the produce and dairy aisles.

Lettuce wraps (think veggie taco shells or leafy tortillas)
Portobello mushrooms (great options for burger bun substitutes)
Cheese crisps (crunchy and a great substitute for crackers)
Zoodles (raw zucchini put through a spiralizer to replace noodles)

The Takeaway

Ultimately, there is no silver bullet when it comes to what bread is good for people with diabetes. But through a combination of homemade, store bought, and produce or dairy based bread substitutes, you can find something to scratch your bread itch without sacrificing stable and lower blood glucose levels.

If you want to live a low carb lifestyle and reclaim your metabolic health, Virta Health may be able to help. By making healthy lifestyle changes in a medical setting with supportive resources like 1:1 virtual coaching, you can regain control of your health and feel like yourself again. See if you’re eligible for Virta Health here.

This blog is intended for informational purposes only and is not meant to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or any advice relating to your health. View full disclaimer

Are you living with type 2 diabetes, prediabetes, or unwanted weight?

You've Been Diagnosed With Type 2 Diabetes. Now What?

What Happens When You Stop Taking Ozempic & Other GLP-1s?

What to Eat or Drink Before a Glucose Test

How Does Dehydration Affect Type 2 Diabetes?

Tips for a Successful Pregnancy with Type 2 Diabetes

Is Gluten-Free Good for Type 2 Diabetes?

Frequently asked questions.

Gluten Free Stuffed Flatbread

This gluten free stuffed flatbread is filled with a delicious mix of swiss chard, parsley and cheese – but the filling recipe is incredibly flexible and you can tweak it to use whatever ingredients you have on hand. the gluten free dough handles beautifully: you can easily roll it out until it’s very thin and assemble the flatbread without any issues or tearing. it’s then pan-fried until golden and crispy and simply irresistible..

I’ve made this flatbread at least four or five times just in the last week, and I still can’t get enough of it. While it may look simple on the surface – it’s just a very basic dough, rolled out until it’s super thin and then stuffed with a mix of chard, parsley and cheese – something truly magical happens when you combine these elements together and pan-fry the flatbread to golden, crispy perfection.

The recipe uses a yeast-free variation of my gluten free pita bread dough , which works perfectly: you can easily roll it out until it’s very thin and then assemble the stuffed flatbreads without any issues or tearing.

A hand holding a stack of gluten free stuffed flatbread that's been cut into wedges.

When it comes to the filling, I basically used whatever we had in our garden and in the fridge. But you could easily play around with other ingredients in the filling, such as spinach instead of the chard or feta cheese instead of cheddar. I’m also planning on testing out a version with zucchini (courgettes) soon, but I’ve also seen variations made with other veggies. Or, you could make a purely cheese-stuffed version with a variety of cheeses, such as a mix of shredded mozzarella and cheddar! The options are endless.

For the best possible texture and taste, these flatbreads are pan-fried in a bit of olive oil . This makes them wonderfully rich and it gives them a delicious crispness (though note that they’ll lose most of their crispy texture as they cool). And you can easily store them until the next day and then reheat them on the stovetop – this actually makes them *extra* crispy!

Overhead view of gluten free stuffed flatbread on a wooden serving board.

Before we get to the bits and bobs of making this amazing stuffed flatbread – if you like what you’re seeing, subscribe to my newsletter to keep up to date on the latest recipes and tips!

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Note: the whole recipe, including the ingredient quantities, can be found at the bottom of this page – just scroll down to the bottom, or click the ‘Jump to Recipe’ button at the top of this post.

The inspiration: Turkish gozleme

When developing this recipe, I was inspired by the Turkish savoury stuffed flatbread called ‘gozleme’ – but this is by no means a traditional interpretation of that recipe, it’s just loosely based on it. Gozleme can be prepared with either a leavened or unleavened dough, typically made from wheat flour, water, salt and sometimes yeast. Some variations also include yoghurt in the dough.

It can be stuffed with a variety of fillings, the most commonly encountered ones being minced lamb with an abundance of spices and a spinach and feta version – but there are many other variations out there as well. It’s cooked on the stovetop with a bit of olive oil, which makes it deliciously crispy, and it’s then cut into smaller, easy-to-grab portions before serving.

Gluten free stuffed flatbread, cut into wedges, served on a large wooden serving board with a small bowl of yoghurt.

The gluten free dough

For this gluten free recipe, I used an unleavened dough that’s based on my gluten free pita bread recipe – it’s essentially that same dough minus the yeast. And it works PERFECTLY for this stuffed flatbread.

The dough comes together quickly and easily either by hand or with a stand mixer, and it handles beautifully thanks to the addition of psyllium husk (in the form of a psyllium gel). You can knead it, shape it and roll it out without any problems whatsoever.

This recipe makes four large-ish flatbreads, so you’ll need to divide the dough into four equal portions and shape each portion into a ball. (As you’re working on one flatbread, keep the other dough balls covered with a clean tea towel to prevent them from drying out.)

The filling

When it comes to the filling, the recipe is super flexible. For this version, I used Swiss chard, plenty of parsley and caramelised shallots (because that’s what’s thriving in our garden at the moment), as well as some cream cheese (for just the right amount of creaminess) and coarsely grated cheddar.

But you can easily use spinach instead of the chard, and swap crumbled feta for the cheddar. You could also add some red pepper flakes, and chopped-up sun-dried tomatoes would be amazing in there as well! So, treat the filling recipe below more as a rough guideline or a gentle suggestion rather than something you have to follow to a T.

A stack of gluten free stuffed flatbread on a wooden serving board.

Shaping the gluten free stuffed flatbread

To shape the stuffed flatbreads:.

Roll out a dough ball into a large oval, about 8×12 inches (20x30cm) in size. It’ll be fairly thin, about 1-2mm.
Use your fingertips to wet the edge of one half of the oval with a bit of water (this will help to seal the stuffed flatbread and prevent the filling from leaking out during cooking).
Place a portion of the filling onto one half of the oval (the one with the wetted edge). Use your hands, the back of a spoon or a small offset spatula to spread out the filling evenly over half of the oval, leaving about ½-inch (1-1.5cm) edge free of the filling.
Fold the other half of the oval over the filling. Gently pat the top to press out any trapped air and then press down with your fingertips along the edges to create a good seal.
There you have it – the assembled stuffed flatbread! Now, repeat with the rest of the dough balls and filling (keep the shaped flatbreads covered with a tea towel to prevent them from drying out).

The first four steps of the 8-step process of assembling gluten free stuffed flatbread.

Cooking the flatbread

It’s best to cook the stuffed flatbread in a large cast iron skillet or frying pan – make sure that it’s at least 11 inches (28cm) in diameter, otherwise your flatbread won’t fit comfortably.

To cook the gluten free stuffed flatbreads:

Heat your skillet or pan over medium heat and, once hot, add about 1 tablespoon of olive oil. (You can adjust the heat as needed during the cooking process, depending on how quickly your flatbread browns.)
Place the flatbread into the skillet and cook it over medium heat for about 2-3 minutes or until it’s deep golden brown underneath.
Flip it and cook it for 2-3 minutes on the other side or until it’s nicely browned underneath. The flatbread will want to puff up because of the trapped steam – use a spatula to gently press down on it, to achieve a more even browning.
Flip it again and cook for about 1 minute, to get both sides perfectly crisp.
Transfer the cooked flatbread to a wire rack, then repeat the cooking process with the remaining flatbreads.

The first four steps of the 6-step process of pan-frying gluten free stuffed flatbread.

Serving the gluten free stuffed flatbread

For maximum crispness, eat the flatbread straight away while it’s still hot. I like to slice them into easy-to-grab wedges, and serve them with some yoghurt for dipping.

However, these are also absolutely incredible lukewarm or cooled completely to room temperature – they just won’t be as crisp. In fact, the flavour of the filling is actually more intense if you serve the flatbread at room temperature.

Storage & reheating

This gluten free stuffed flatbread is definitely at its best fresh, on the day of preparation, but it also keeps really well until the next day in a closed container in the fridge.

The next day, you can reheat it in a hot pan: just cook it over medium to medium-high heat for 4-5 minutes, flipping it occasionally. That will actually make it even crisper than it was on day one!

The made ahead option

You can also prep the stuffed flatbread in advance!

For this, you need to fully assemble the flatbreads, place them on a baking sheet, cover it tightly with plastic wrap/cling film and then store it in the fridge overnight. You can then cook and serve the flatbreads the next day.

Possible substitutions

Although all the ingredients in the recipe should be easily accessible either in your local grocery store or online, I still wanted to include a list of substitutions you can make. (NOTE: all substitutions should be made by weight and not by volume.)

Psyllium husk: YOU CAN’T SUBSTITUTE IT WITH A DIFFERENT INGREDIENT. But if you use psyllium husk powder as opposed to the whole psyllium husk, use only 85% of the weight listed in the recipe. You can read more about the role of psyllium husk in gluten free bread here!
Millet flour: You can use an equal weight of finely ground/milled brown rice flour instead.
Tapioca starch: You can use an equal weight of cornstarch (US)/cornflour (UK), potato starch or arrowroot starch instead.

And, as I’ve mentioned above, you can also play around with the filling ingredients depending on what you have on hand and what you fancy eating.

A note on measurements (tl;dr: if possible, use a scale)

While I’ve included the volume measurements (cups and spoons) in the recipe card below, if at all possible (and I really cannot overemphasise this): USE METRIC GRAM MEASUREMENTS IF YOU CAN.

They’re much more precise and produce more reliably delicious results. This is true for pretty much all of baking – a kitchen scale will invariably give better results than cups and tablespoons.

And that’s it! This covers everything you need to know about this AMAZING gluten free stuffed flatbread. It really is incredibly delicious, even non-gluten-free folks can’t get enough of it. And it’s super easy to make, the recipe is pretty much fail-proof.

I really hope you’ll love it as much as I do.

More gluten free bread recipes

If you’re looking for more amazing gluten free bread recipes (that are nearly indistinguishable from their “regular” equivalents made from wheat flour), you’re definitely in the right place!

Easy Gluten Free Pita Bread

Quick & easy gluten free naan (no yeast).

Easy 5-Ingredient Gluten Free Flour Tortillas
The Fluffiest Gluten Free Burger Buns
Gluten Free Ciabatta Rolls
Easy Gluten Free Pizza Dough
Easy Gluten Free Focaccia

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Ingredients

▢ 1 tbsp olive oil
▢ 3 shallots, diced (or 1 medium yellow onion)
▢ 300 g (10oz) Swiss chard, roughly chopped (or spinach)
▢ 35 g (about 1 bunch) fresh parsley, most of the stems removed, roughly chopped
▢ 55 g (¼ cup) full-fat cream cheese
▢ 100 g (1 cup) coarsely grated/shredded cheddar cheese
▢ salt and pepper, to taste

Gluten free dough:

▢ 12 g (2½ tbsp) whole psyllium husk (rough husk form) (If using psyllium husk powder , use only 10g.)
▢ 240 g (1 cup) lukewarm water
▢ 135 g (1 cup) millet flour, plus extra for flouring the surface (You can use an equal weight of finely ground/milled brown rice flour instead.)
▢ 75 g (⅔ cup) tapioca starch (You can use an equal weight of cornstarch (US)/cornflour (UK), potato starch or arrowroot starch instead.)
▢ 10 g (2 tsp) caster/superfine or granulated sugar
▢ 4 g (¾ tsp) salt
▢ 15 g (1 tbsp) olive oil

You'll also need:

▢ 4 tbsp olive oil, for pan-frying the flatbread
▢ fresh parsley, finely chopped, for serving

Instructions

Making the filling:.

Heat a frying pan over a medium heat.
Add the olive oil and chopped shallots. Season with salt and cook the shallots with occasional stirring until they've softened and caramelised. This should take about 5-10 minutes. Adjust the heat as necessary.
Once the shallots have caramelised, add the Swiss chard (or spinach) and cover the pan with a lid. Cook over medium heat with occasional stirring until the chard has fully wilted. Uncover the pan and cook for a further 1-2 minutes until most of the moisture released by the chard has evaporated.
Transfer to a large bowl and allow to cool completely to room temperature.
Once cooled, add the cream cheese, coarsely grated cheddar, salt and pepper, and mix well until evenly combined. Make sure to taste the filling and adjust the seasoning. Set aside until needed.

Making the dough:

You can make the dough by hand or using a stand mixer fitted with the dough hook attachment.
Make the psyllium gel: In a bowl, mix together the psyllium husk and lukewarm water. After about 30-45 seconds, a gel will form.
In a separate large bowl (or the bowl of a stand mixer, if using), whisk together the millet flour, tapioca starch, sugar and salt.
Add the olive oil to the psyllium gel and mix well to combine, then add them to the dry ingredients.
Knead everything together into a smooth, supple dough that comes away from the sides of the bowl (it shouldn't be too sticky to the touch). Scrape the sides and bottom of the bowl as necessary, to avoid any patches of dry flour.

Assembling the stuffed flatbread:

See the blog post for detailed step-by-step photos of the assembling process.
Turn out the dough onto a lightly floured surface and divide it into 4 equal portions. You can use a scale to make sure that they’re all of equal weight (each portion should weigh about 122g) or you can just eyeball it.
Shape the pieces of dough into balls and cover them with a clean tea towel, to prevent them from drying out.
On a lightly floured surface, roll out a dough ball into a large oval, about 8x12 inches (20x30cm) in size. It’ll be fairly thin, about 1-2mm.
Place one quarter of the filling onto one half of the oval (the one with the wetted edge). Use your hands, the back of a spoon or a small offset spatula to spread out the filling evenly over half of the oval, leaving about ½-inch (1-1.5cm) edge free of the filling.
Fold the other half of the oval over the filling. Gently pat the top to press out any trapped air and then press down with your fingertips along the edges to create a good seal.
Repeat with the rest of the dough balls and filling. Keep the shaped flatbreads covered with a tea towel to prevent them from drying out.

Cooking the flatbread:

Heat a large skillet or pan over medium heat and, once hot, add about 1 tablespoon of olive oil. (You can adjust the heat as needed during the cooking process, depending on how quickly your flatbread browns.)
Transfer the cooked flatbread to a wire rack, then repeat the cooking process with the remaining flatbreads.
For maximum crispness, eat the flatbread straight away while it’s still hot. Slice them into easy to grab wedges, and serve them with some yoghurt for dipping.
You can also allow them to cool until lukewarm or at room temperature – but note that they won’t be as crisp. However, the flavour of the filling is actually more intense if you serve the flatbread at room temperature.

Storage & reheating:

This gluten free stuffed flatbread is definitely at its best fresh, on the day of preparation, but it also keeps really well until the next day in a closed container in the fridge. The next day, you can reheat it in a hot pan: just cook it over medium to medium-high heat for 4-5 minutes, flipping it occasionally. That will actually make it even crisper than it was on day one!

Pinterest image for gluten free stuffed flatbread.

More gluten free flatbread recipes

Easy gluten free flour tortillas (only 5 ingredients).

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and I’m so glad to welcome you to The Loopy Whisk, where we’re all about feel good recipes that make living with food allergies and dietary requirements easy as cake! (And there’s a lot of cake round these parts.) I’m happiest in the kitchen and behind the camera, bringing my allergy friendly dreams to life, and sharing them with you.

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16 Gluten-Free Cookies So Good, You Won't Notice the Difference

All of the flavor, none of the gluten.

Whether you have a gluten intolerance or simply want to broaden your baking skills to be inclusive for all your friends, family, and guests, this collection of delicious gluten-free cookie recipes truly has something for everyone. From the best gluten-free chocolate chip cookie recipe to classic sugar cookies , keep scrolling to find your find your next go-to gluten-free recipe.

Brown Butter-Cassava Flour Snickerdoodle Cookies

"Delicious and gluten-free!" — Sophia Terrazas-Chadwick

Gluten-Free Sugar Cookies

"Excellent cookie... They don't break apart nor do they bend once cooled so they were ideal for decorating. I left them covered with cheesecloth on the counter overnight and decorated the next day and packaged once the icing dried. They make great gift cookies. Thank you for sharing this recipe." — Buckwheat Queen

Gluten-Free Chocolate Chip Cookies

"These cookies are delicious and I can't really tell that they are gluten-free. Baked beautifully! I also used some butterscotch chips. Thanks!" — Zosgood

Gluten-Free Double Chocolate Cookies

"These are the best gluten-free cookies I have ever made. The only changes I made were I used 1 c. of Bob's Red Mill Gluten Free 1-to-1 flour instead of the four different flours in the recipe (omit the xanthan gum since Bob's already has it) and used dark chocolate chips. The flavor is incredible and the texture is spot on! Highly recommend!" — KW

Gluten-Free Sandwich Cookies with Dulce de Leche (Alfajores)

"I just love them. Being Argentinian and living in another country, by following this recipe I always feel at home." — Anitasuperpoderosa_89

Flourless Peanut Butter Cookies

"Divine! These are the best peanut butter cookies! My mom can't get enough of these either. One thing I would make note of is that this recipe doesn't make very much. I highly recommend doubling the amounts." — Java_Girl

Meringue Cookies

"Easily best cookies I’ve ever had. My 10 year old cousins came up from Florida to Baltimore last month. We hadn’t seen them in 3 years, as they live so far away. They made me signs about the cookies I made from when they were 7 years old. I had to make them, and my cousins were so happy. 100 percent recommend." — Goldenfood

Simple Gluten-Free Snickerdoodle Cookies

"This recipe turned out really well! A very light soft cookie with a bit of toasty on the outside! It's my first time making Snickerdoodle cookies and heard to call of cream of tartar not being present, did my research and added 1/4 tsp. Not sure if it made a difference but my cookies are checking the traditional box, light and delicious!" — Angela Sackett Superhotmama

Gluten-Free Toll House Cookies

"These were a bit heavier than a traditional chocolate chip cookie, almost cake-like. They remained puffy instead of spreading out flat. Thank you for the recipe." — Buckwheat Queen

"Delicious! My family (with 4 kids) always eats all of them within an hour or two! We hardly ever cook gluten-free, but I had almond flour so I decided to try it. My husband told me to buy more almond flour, because these are so delicious. I used regular sugar and followed the recipe exactly." — LivinginJapan

Gluten-Free Gingersnap Cookies

"These were delicious! They turned out great and I'll be making these again." — Kate

Gluten-Free Peanut Butter Cookies

"These have become my go-to for gluten-free cookies. My sister has celiac and I LOVE peanut butter, so this is perfect because I think the absence of flour (even GF flour) makes the peanut butter stand out more. I really like it with the modification of 1/2 white 1/2 brown sugar and adding a pinch of baking powder." — 88keys4god

Gluten-Free Magic Cookie Bars

"Wow! Amazing! Dessert can be delicious without the gluten! Because several others had mentioned it was sticky, I spread butter in the bottom of my stoneware jelly pan and no problems. This was my first try at gluten free and it was a success! I made these for a friend who is gluten free, but my son ended up eating half of them! Thank you, Jewel! I will make these again!" — Momof3

Flourless Fudge Cookies

"Loved these. Made them for a tailgate and they were a big hit with the college crowd. They held together well. Crispy on the outside and chewy chocolate on the inside. I cheated and used egg whites from a carton, no problem. I thought they tasted better on the day after I made them." — Sue

Perfect Cashew and Peanut Butter Gluten-free Cookies

"I have just been diagnosed myself gluten-free lifestyle, so needless to say..I am experimenting. I was so amazed at how these tasted. This was a pleasure to bake and eat. I did substitute butter instead of margarine and used 1/2 the corn flour mixture and substituted it w/ rice flour instead for the remaining half. Excellent, thanks!" — Rev. Michaela

3-Ingredient Peanut Butter Cookies

"This cookie was very easy to make. It was a must-have with the family and I will keep this recipe." — Allrecipes Member

More Inspiration

My Go-To Secret for Exceptional Gluten-Free Baking
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COMMENTS

Recent practical researches in the development of gluten-free breads
A unique property of wheat gluten realizes bread with high quality. However, some genetically predisposed people cannot eat wheat bread, because gluten causes harmful reactions to them. In this short review, we will summarize the gluten-dependent swelling mechanism of wheat bread and the recent scientific effort to make bread without gluten. Go to:
A Systematic Review on Gluten-Free Bread Formulations Using Specific
This study aimed to perform a systematic review on gluten-free bread formulations using specific volumes as a quality indicator. In this systematic review, we identified 259 studies that met inclusion criteria. From these studies, 43 met the requirements ...
Glycemic Index of Gluten-Free Bread and Their Main Ingredients: A
The increasing demand for gluten-free products, primarily GF bread with a good nutritional profile and sensory quality, justify the importance and the need to evaluate the glycemic index of gluten-free bread and the main ingredients used in their formulations.
Recent developments in gluten-free bread baking approaches: A review
Gluten-free bread is usually characterised by an overall poorer quality compared to wheat bread. On average, it has a lower nutritional value as it is mostly based on starch and refined flours [1, 2].
Innovative approaches towards improved gluten-free bread properties
Although the production of GF bread still remains a technological challenge, research continues to find innovative approaches to improve the quality of GF bread. Literature shows that an important aim is to imitate the gluten-network by combining several ingredients, from which hydrocolloids play a crucial role.
Texture profile analysis and sensory evaluation of ...
The need for better quality gluten-free (GF) bread is constantly growing. This can be ascribed to the rising incidence of celiac disease or other gluten-associated allergies and the widespread incorrect public belief, that GF diet is healthier. Although there is a remarkable scientific interest shown to this topic, among the numerous studies only a few deals with commercially available ...
Physicochemical, nutritional, and functional characterization of gluten
Despite the commercial availability of gluten-free (GF) products, numerous nutritional, sensory, and textural limitations have been brought to the att…
A Systematic Review of Gluten-Free Dough and Bread ...
PDF | High-quality, gluten-free doughs and bakery products are clearly more difficult to produce than wheat flour-based products. The poor quality of... | Find, read and cite all the research you ...
Gluten-Free Breadmaking: Facts, Issues, and Future
Abstract Gluten-free foods have attracted increased attention in the food industry due to health issues (i.e., celiac disease and other gluten-related disorders) associated with gluten and the changes in eating habits, such as following gluten-free diet (GFD). Among this food segment, gluten-free (GF) bread plays a crucial role because of the stable consumption of bread in many parts of the ...
A Systematic Review of Gluten-Free Dough and Bread: Dough ...
High-quality, gluten-free doughs and bakery products are clearly more difficult to produce than wheat flour-based products. The poor quality of the breads that are currently available demonstrates that manufacturing remains a significant technological problem. This is mainly due to the absence of gluten, which has a huge negative impact on dough rheology and bread characteristics. Gluten ...
Current and forward looking experimental approaches in gluten-free
The techniques used in gluten-free bread making research vary widely. This review focuses on the methodological aspects of gluten-free bread making research and extracts relevant data from all Web of Science peer reviewed research articles on gluten-free bread published from 2010 to date.
Development of Gluten-Free Bread Production Technology with ...
This research aims to enhance the nutritional value of gluten-free bread by incorporating a diverse range of components, including additives with beneficial effects on human health, e.g., dietary fibers. The research was focused on improving the texture, taste, and nutritional content of gluten-free products by creating new recipes and including novel biological additives. The goal was to ...
Gluten-Free Breadmaking: Facts, Issues, and Future
Request PDF | Gluten-Free Breadmaking: Facts, Issues, and Future | Gluten-free foods have attracted increased attention in the food industry due to health issues (i.e., celiac disease and other ...
Gluten-Free Breads: The Gap Between Research and Commercial ...
The market for gluten-free products is steadily growing and gluten-free bread (GFB) keeps on being one of the most challenging products to develop. Although numerous research studies have worked on improving the manufacture of GFBs, some have adopted approaches far from commercial reality. This review analyzes the ingredient list and nutrition ...
Advances in gluten-free bread technology
The unattractive appearance of gluten-free bread still remains a challenge in gluten-free breadmaking. In response to this, additives such as dairy products, soya and eggs have been used to improve the quality of gluten-free bread, but with limited success. In recent years, enzymes (transglutaminase …
Recent practical researches in the development of gluten-free ...
In this short review, we introduce the ongoing advancements in the development of gluten-free bread, by our laboratory as well as others, focusing mainly on rice-based breads.
Understanding gluten-free bread ingredients during ohmic ...
Due to the absence of gluten, several challenges arise during gluten-free (GF) bread baking, affecting the mid-and-end-product quality. The main approach to overcome this issue is to combine certain functional ingredients and additives, to partially simulate wheat bread properties. In addition, the optimization of the baking process may contribute to improved product quality. A recent and very ...
Gluten‐Free Breads: The Gap Between Research and Commercial Reality
The market for gluten-free products is steadily growing and gluten-free bread (GFB) keeps on being one of the most challenging products to develop. Although numerous research studies have worked on improving the manufacture of GFBs, some have adopted approaches far from commercial reality.
Gluten-Free Bread and Bakery Products Technology
Bread and bakery products are an essential part of the daily diet. Therefore, new naturally gluten-free baking ingredients and new methods of processing traditional ingredients are sought.
USDA Scientists Produce Palatable Gluten-Free Bread
ARS scientists have developed a new process to produce gluten-free bread from corn flour that produces higher quality bread that is closer to the texture of conventional bread like those pictured here. Click the image for more information about it.
Savory, homemade bread
At that time, where I lived in Alabama anyway, there were no gluten-free breads in the freezer case at my local grocery store, like there are now and there were no gluten-free baked goods to be ...
Bread Experts Share 11 Tips For Making Gluten-Free Sourdough
Ensure success when making a gluten-free sourdough starter with these expert-approved tips. You'll be baking gluten-free breads, desserts, and more in no time.
The Reason Sourdough Bread May Still Work For A Gluten-Free Diet
If you have celiac disease, sourdough bread is off the table, but if you typically avoid bread as part of a gluten-free diet, sourdough can still be an option.
Gluten-Free Sourdough Bread Recipe
A gorgeous loaf of gluten-free sourdough bread is possible — and simple — thanks to our Gluten-Free Bread Flour and gluten-free sourdough starter. Bake it today!
Compliance and Attitudes towards the Gluten-Free Diet in Celiac ...
In conclusion, it is important to periodically monitor celiac patients' compliance and attitudes towards the gluten-free diet. As also highlighted in international guidelines, a reorganization of the diagnosis/follow-up visits, including an expert dietary consultation, is needed.
A Review on the Gluten-Free Diet: Technological and Nutritional
The nutritional profiles of gluten-free products, as well as the dietary intake patterns of individuals on the diet, were assessed in several studies. According to Do Nascimento et al. [ 117 ], gluten-free products share a common composition of raw ingredients, including corn, rice, soy, cassava, and potato.
Is yeast gluten-free?
If you're baking gluten-free, you know that some unexpected ingredients may contain gluten. One common question we get: Is yeast gluten-free? Yes, the kind of yeast that's used for baking bread is gluten-free. Baker's yeast is a single-cell organism that consumes sugar and starch and produces carbon dioxide and alcohol through fermentation.
What Bread is Best for Type 2 Diabetes?
Is there a good bread substitute for people with diabetes? Take a look at some of the smartest bread substitutes for type 2 diabetes.
Gluten Free Stuffed Flatbread
This gluten free stuffed flatbread is filled with a delicious mix of Swiss chard, parsley and cheese, and it's super easy to make!
16 Gluten-Free Cookies So Good, You Won't Notice the Difference
From the best gluten-free chocolate chip cookies and classic gluten-free sugar cookies to meringue, these are our 16 best gluten-free cookie recipes.

Gluten-Free Breadmaking: Facts, Issues, and Future

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Understanding gluten-free bread ingredients during ohmic heating: function, effect and potential application for breadmaking

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Introduction

Gluten-free batter and bread properties

Critical parameters during OH

Effect of gluten-free batter ingredients on the ohmic heating process

Dietary fiber, sugar, and hydrocolloids

Fat and emulsifiers

Conclusions

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U.S. DEPARTMENT OF AGRICULTURE

USDA Scientists Produce Palatable Gluten-Free Bread

Bread Experts Share 11 Tips For Making Gluten-Free Sourdough

1. Start with a whole grain gluten-free flour

2. Use sorghum flour for a soft bread with moderate sweetness

3. Add psyllium husk to help your sourdough stretch

4. Scoop in teff flour for a nutty flavor

5. Use glutinous rice flour to give your dough some stretchiness

6. Use a fruity ferment to kickstart your sourdough starter

7. Try buckwheat flour in your gluten-free sourdough

8. Brown rice flour is a plausible alternative for gluten-based flour

9. Swap millet flour into your gluten-free sourdough

10. Skip the beer

11. Tips for making gluten-free sourdough

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A Review on the Gluten-Free Diet: Technological and Nutritional Challenges

Skye Balfour-Ducharme

1. Introduction

2. Gluten-Free Products

2.1. Gluten Functionality