Gluten weight in ancient and modern wheat and the reactivity of epitopes towards R5 and G12 monoclonal antibodies

Comparative characterization of the gluten and fructan contents of breads from industrial and artisan bakeries: a study of food products in the Spanish market

Background

The consumption of wheat/gluten is associated with adverse reactions for human health. Gluten and fructans are identified as the major compounds triggering and worsening adverse reactions to wheat, which are increasing, and as a consequence, avoidance of gluten/wheat is the common strategy of many individuals of the western population. Although bread is a product of daily consumption, there is a lack of information on the gluten and fructan contents and the influence of artisanal or industrial processes.

Objective

The aim of this study is to carry out a comparative characterization between artisan bakeries and hypermarkets in Spain for gluten and fructan contents in daily sold breads.

Design

A total of 48 types of bread highly consumed in Spain sold in artisan bakeries (long fermentation) and hypermarkets (short fermentations) were selected for comparing the gluten and fructan contents. Methods such as reverse phase-high performance liquid chromatography (RP-HPLC), R5 monoclonal antibody (moAb), and fructans protocols were used for the quantification of these compounds.

Results

Great variation for the content of gluten and fructans has been found between all bread categories. Although breads produced using long fermentation (artisan bakeries) contain significantly lower gluten, they have higher fructans than those using short fermentations (hypermarkets). Durum wheat breads had the lowest content of gluten. Moreover, spelt breads from artisan bakeries had the lowest content of fructans but not those from hypermarkets.

Discussion

In this study, we report the comparative characterizarion of the breads of the Spanish market. These food products presented variation in the amount of gluten and fructans, ligated in most of the cases to the nature of the providers: artisan bakeries against hypermarkets. Depending on the type of bread, the differences for the daily consumption of gluten and fructan can be 4.5 and 20 times, respectively.

Conclusions

We found strong differences for gluten and fructan contents among breads. These information may contribute to designing strategies to improve the management of gluten and fructans in bread.

Do ancient wheats contain less gluten than modern bread wheat, in favour of better health?

Popular media messaging has led to increased public perception that gluten‐containing foods are bad for health. In parallel, ‘ancient grains’ have been promoted with claims that they contain less gluten. There appears to be no clear definition of ‘ancient grains’ but the term usually includes einkorn, emmer, spelt and Khorasan wheat. Gluten is present in all wheat grains and all can induce coeliac disease (CD) in genetically susceptible individuals. Analyses of ‘ancient’ and ‘modern’ wheats show that the protein content of modern bread wheat (Triticum aestivum) has decreased over time while the starch content increased. In addition, it was shown that, compared to bread wheat, ancient wheats contain more protein and gluten and greater contents of many CD‐active epitopes. Consequently, no single wheat type can be recommended as better for reducing the risks of or mitigating the severity of CD. An estimated 10% of the population of Western countries suffers from gastrointestinal symptoms that lack a clear organic cause and is often referred to as irritable bowel syndrome (IBS). Many of these patients consider themselves gluten sensitive, but in most cases this is not confirmed when tested in a medical setting. Instead, it may be caused by gas formation due to fermentation of fructans present in wheat or, in some patients, effects of non‐gluten proteins. A significant overlap of symptoms with those of CD, IBS and inflammatory bowel disease makes a medical diagnosis a priority. This critical narrative review examines the suggestion that ‘ancient’ wheat types are preferred for health and better tolerance.

A Tomato Pomace Enriched Gluten-Free Ready-to-Cook Snack’s Nutritional Profile, Quality, and Shelf Life Evaluation

Attempts were undertaken to design a quick ready-to-cook gluten-free snack utilizing finger millet and potato flour (50:50) as well as tomato pomace due to the restricted availability of gluten-free snack goods in the Indian market. The nutritional content of the food and its general acceptability, cooking characteristics, and storage stability were all tested. The addition of tomato pomace had a distinct influence on the product’s color and hardness. Additionally, it resulted in a significant reduction in the amount of oil used, cooking loss, and frying time required. With a high acceptance level, the snack supplemented with 10% tomato pomace was determined to be the most optimal formulation. When the same substance was subjected to FTIR analysis, it was discovered that it retained all the important functional groups required for sustaining antioxidant activity. It also displayed high storage stability, a desirable overall acceptance score, and a very promising nutritional profile, all of which would benefit the product’s end users.

Influences of grain and protein characteristics on in vitro protein digestibility of modern and ancient wheat species

BACKGROUND

The resistance of proteins to gastrointestinal digestion contributes to their ability to act as allergens. Near-complete digestion of protein in wheat products is important with respect to avoiding the potential immunogenic effects of undigested peptides. Five modern US wheat classes (soft red winter, hard winter, hard red spring, club and durum) including 17 wheat varieties, as well as three ancient wheat classes (spelt, emmer and einkorn) including nine wheat varieties, were analyzed for kernel hardness (KH) and flour protein characteristics, in addition to in vitro protein digestibility (IVPD) of cooked flour, flour without albumins and globulins (FWOAG), gluten, albumins, and globulins, aiming to identify the factors influencing the protein digestibility of flour.

RESULTS

IVPDs of flour, FWOAG, gluten and albumins of wheat varieties ranged from 86.5% to 92.3%, 85.8% to 90.3%, 90.6% to 94.6% and 74.8% to 85.1%, respectively. The IVPD of gluten was significantly higher than the IVPDs of flour and FWOAG, indicating that non-protein components substantially affect protein digestibility. Significant differences were observed in IVPDs of flour and albumins among eight wheat classes, but not in the IVPDs of FWOAG, gluten and globulins. There were apparent differences in undigested protein bands and intensities of wheat classes with low and high flour IVPDs. KH and albumin proportion exhibited negative and positive relationships, respectively, with flour IVPD.

CONCLUSION

The results of the present study demonstrate that KH, non-protein components and albumin proportion have a major influence on protein digestion and need to be considered when developing wheat cultivars with higher protein digestibility.

Characteristics of Technological Properties of Grain and Flour from Ancient Varieties of Wheat (Einkorn, Emmer and Spelt)

The study presents assessment of commodity characteristics of grains from ancient varieties of wheat (einkorn, emmer and spelt) in comparison to grains of the conventional wheat cultivar Arkadia. The findings related to the grain of einkorn and emmer were very similar, and far worse than those related to spelt grain; the latter were found with better ratings, sometimes even in comparison to the conventional wheat grain (e.g. the highest mass-weight density). Similar relationships were observed between the flours produced by milling the grains. Analysis of the indirect baking quality indicators showed that flours from einkorn and emmer can effectively be used for baking purposes, however they present low technological value. The flour from emmer wheat was found to be the poorest, which was confirmed e.g. by the low gluten number, gluten index, Zeleny’s index, and high gluten spreadability. Spelt flour was found to present moderate technological value. Based on the results it can be concluded that by using adequate modification in the process of dough kneading and fermentation it will be possible to produce high quality baked goods from ancient wheat grains.

Pathogenesis of Celiac Disease and Other Gluten Related Disorders in Wheat and Strategies for Mitigating Them

Wheat is a major cereal crop providing energy and nutrients to the billions of people around the world. Gluten is a structural protein in wheat, that is necessary for its dough making properties, but it is responsible for imparting certain intolerances among some individuals, which are part of this review. Most important among these intolerances is celiac disease, that is gluten triggered T-cell mediated autoimmune enteropathy and results in villous atrophy, inflammation and damage to intestinal lining in genetically liable individuals containing human leukocyte antigen DQ2/DQ8 molecules on antigen presenting cells. Celiac disease occurs due to presence of celiac disease eliciting epitopes in gluten, particularly highly immunogenic alpha-gliadins. Another gluten related disorder is non-celiac gluten-sensitivity in which innate immune-response occurs in patients along with gastrointestinal and non-gastrointestinal symptoms, that disappear upon removal of gluten from the diet. In wheat allergy, either IgE or non-IgE mediated immune response occurs in individuals after inhalation or ingestion of wheat. Following a life-long gluten-free diet by celiac disease and non-celiac gluten-sensitivity patients is very challenging as none of wheat cultivar or related species stands safe for consumption. Hence, different molecular biology, genetic engineering, breeding, microbial, enzymatic, and chemical strategies have been worked upon to reduce the celiac disease epitopes and the gluten content in wheat. Currently, only 8.4% of total population is affected by wheat-related issues, while rest of population remains safe and should not remove wheat from the diet, based on false media coverage.

Adverse Reactions to Wheat or Wheat Components

Wheat is an important staple food globally, providing a significant contribution to daily energy, fiber, and micronutrient intake. Observational evidence for health impacts of consuming more whole grains, among which wheat is a major contributor, points to significant risk reduction for diabetes, cardiovascular disease, and colon cancer. However, specific wheat components may also elicit adverse physical reactions in susceptible individuals such as celiac disease (CD) and wheat allergy (WA). Recently, broad coverage in the popular and social media has suggested that wheat consumption leads to a wide range of adverse health effects. This has motivated many consumers to avoid or reduce their consumption of foods that contain wheat/gluten, despite the absence of diagnosed CD or WA, raising questions about underlying mechanisms and possible nocebo effects. However, recent studies did show that some individuals may suffer from adverse reactions in absence of CD and WA. This condition is called non-celiac gluten sensitivity (NCGS) or non-celiac wheat sensitivity (NCWS). In addition to gluten, wheat and derived products contain many other components which may trigger symptoms, including inhibitors of α-amylase and trypsin (ATIs), lectins, and rapidly fermentable carbohydrates (FODMAPs). Furthermore, the way in which foods are being processed, such as the use of yeast or sourdough fermentation, fermentation time and baking conditions, may also affect the presence and bioactivity of these components. The present review systematically describes the characteristics of wheat-related intolerances, including their etiology, prevalence, the components responsible, diagnosis, and strategies to reduce adverse reactions.

Comparison of gluten peptides and potential prebiotic carbohydrates in old and modern Triticum turgidum ssp. genotypes

Old wheat genotypes are perceived by consumers as healthier than modern ones. The release of gluten peptides with in vitro digestion and the content of potentially prebiotic carbohydrates (i.e. resistant fraction of starch and cell-wall associated dietary fiber) were evaluated in tetraploid wheats, namely 9 old and 3 modern Triticum turgidum ssp. genotypes. Simulated digestion of wholemeal flours yielded 152 major peptides, 59 of which were attributed a sequence. Principal component analysis revealed that peptide profiles were variable in old genotypes, unlike in modern ones. Digestion of old genotypes generally yielded peptides in greater concentration. In particular, 5 peptides of γ-gliadin, known to trigger the adaptive immune reaction, and two peptides of α-gliadin, known to be toxic to celiac patients, were particularly abundant in some old varieties. Resistant starch (RS) was negligible in modern genotypes (<0.6%), but it was remarkably abundant in some old varieties, reaching the highest value in Dauno III (8.5%, P < 0.05). Dauno III also presented the highest amount of soluble fiber (4.2%, P < 0.05). Pasta was made with an old and a modern genotype (Dauno III and PR22D89, respectively) with opposite RS content. Pasta making and cooking affected starch digestibility, overtaking differences between genotypes and yielding the same amount of RS for both the varieties (approx. 1.7%). The data herein presented suggest that the wholemeal flours of old tetraploid wheat genotypes could not boast particular claims associated to a lower exposure to gluten peptides and, if cooked, to a prebiotic potential.

Genetic and environmental factors affecting the expression of α-gliadin canonical epitopes involved in celiac disease in a wide collection of spelt (Triticum aestivum ssp. spelta) cultivars and landraces

BACKGROUND

Celiac disease (CD) is an autoimmune disorder affecting genetically predisposed individuals whose dietary gluten proteins trigger an inflammatory reaction in the small intestine. Gluten is found in the seeds of cereals like bread wheat (Triticum aestivum ssp. aestivum) and spelt (Triticum aestivum ssp. spelta). The development of new varieties lacking immunogenic peptides is one of the strategies currently investigated to address the CD problem. Among gluten proteins, α-gliadins display the strongest immunogenicity with four main T-cell stimulatory epitopes. The objective of this work was to study the expression of α-gliadin epitopes related to CD in a wide collection of 121 spelt accessions (landraces and varieties, spring and winter accessions) from different provenances, and to analyze the correlation between the presence of epitope sequences in gDNA and their expression (cDNA). The effect of environmental factors (harvest year and N fertilization) on the epitope expression was also investigated.

RESULTS

TaqMan probes targeting the canonical form of the epitopes were used to evaluate the epitope expression levels. Significant variations in the amount of epitope transcripts were identified between accessions and according to the provenances. Spring accessions showed a significantly higher immunogenicity than winter ones and no influence of spelt breeding on the epitope expression levels could be assessed when comparing landraces and varieties from Northwestern Europe. No correlation was observed between quantitative PCR results obtained from cDNA and gDNA for 45 accessions tested, stressing the need to use markers focusing on epitope transcripts rather than on genomic sequences. A relative stability of the amount of epitopes expressed by a same accession across four harvest years was detected. The fertilization strategy, evaluated through seven N fertilization modalities applied to two commercial spelt varieties, did not influence the epitope expression of the first variety, whereas it had a slight effect for the second one.

CONCLUSIONS

The results obtained in this work showed that the CD-related epitope expression greatly fluctuated among the spelt accessions studied. This expression was not correlated to the epitope genomic occurrence and environmental factors had almost no influence on the amount of epitope transcripts.

Effect of heat treatment on rheological properties of red kidney bean gluten free cake batter and its relationship with cupcake quality

Legumes and cereals complement their nutritional quality and there is a need of convenience products made with these grains. The objectives of this study were to determine the rheological and functional properties of precooked red kidney bean (RKB) flours and their effect on viscoelastic properties of gluten free cake batter and cupcake quality including consumer acceptance. RKB flours were thermally processed by boiling at 100 °C (0, 20, 30 and 40 min) and drying at 80 °C (3 and 4 h). Rheological properties of cake batter containing 100% RKB flour were tested by creep-recovery and dynamic frequency tests. Batter of RKB flour boiled for 20 min was significantly stiffer with 100 times less deformable character compared to the control. Increase in batter modulus ranged from 2000 times elastic component (G'), 988 times viscous component (G″) and 1805 times complex viscosity (η*) at 20 min boiling. Drying did not have a significant effect on viscoelastic properties. Firmness and height of gluten free RKB cupcake were not affected by heat treatment. RKB gluten free cake after heat-moisture treatment had improved consumer acceptance scores compared to the control. Our findings showed that 20 min boiling and 3 h drying process is adequate for precooked RKB flour.

Do ancient types of wheat have health benefits compared with modern bread wheat?

A number of studies have suggested that ancient wheats have health benefits compared with modern bread wheat. However, the mechanisms are unclear and limited numbers of genotypes have been studied, with a particular focus on Kamut^® (Khorasan wheat). This is important because published analyses have shown wide variation in composition between genotypes, with further effects of growth conditions. The present article therefore critically reviews published comparisons of the health benefits of ancient and modern wheats, in relation to the selection and growth of the lines, including dietary interventions and comparisons of adverse effects (allergy, intolerance, sensitivity). It is concluded that further studies are urgently required, particularly from a wider range of research groups, but also on a wider range of genotypes of ancient and modern wheat species. Furthermore, although most published studies have made efforts to ensure the comparability of material in terms of growth conditions and processing, it is essential that these are standardised in future studies and this should perhaps be a condition of publication.

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Critically appraises the health benefits of ancient wheats in relationship to grain composition.

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Includes human intervention trials and in vitro studies.

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Included metabolic and adverse effects.

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Makes recommendations for future work.