Water absorption capacity determines the functionality of vital gluten related to specific bread volume

Vital gluten is often used in baking to supplement weak wheat flours and improve their baking quality. Even with the same recipe, variable final bread volumes are common, because the functionality differs between vital gluten samples also from the same manufacturer. To understand why, the protein composition of ten vital gluten samples was investigated as well as their performance in a microbaking test depending on the water content in the dough. The gluten content and composition as well the content of free thiols and disulfide bonds of the samples were similar and not related to the specific bread volumes obtained using two dough systems, one based on a baking mixture and one based on a weak wheat flour. Variations of water addition showed that an optimal specific volume of 1.74–2.38 mL/g (baking mixture) and 4.25–5.49 mL/g (weak wheat flour) was reached for each vital gluten sample depending on its specific water absorptio

A Portable Gluten Sensor for Celiac Disease Patients May Not Always Be Reliable Depending on the Food and the User

A strict lifelong gluten-free (GF) diet is currently the only known effective treatment for celiac disease (CD), an inflammatory disorder of the small intestine with a worldwide prevalence of about 1%. CD patients need to avoid wheat, rye, and barley and consume GF foods containing <20 mg/kg of gluten. However, strict adherence to a GF diet tends to reduce the quality of life of CD patients compared to the general population and may lead to fear of inadvertent gluten consumption, especially when eating out. To help alleviate risk of gluten exposure, a portable gluten sensor was developed by Nima Labs that allows CD patients to test foods on site prior to consumption. With very limited independent information on the analytical performance of the Nima sensor available so far, our aim was to evaluate the reliability of the sensor using a variety of different foods with defined gluten content. All samples were tested with the sensor and analyzed by enzyme-linked immunosorbent assay as reference method. Of the 119 samples with gluten content ranging from 2 to 101,888 mg/kg tested in total, the sensor showed 80 positive (67.2%), 37 negative (31.1%) and 2 invalid results at the first of three consecutive measurements. The detection rate for samples containing ≥20 mg/kg of gluten was 90%. Samples containing 2 mg/kg of gluten or below consistently tested negative, but samples with a gluten content between 2 to 20 mg/kg of gluten may either test positive or negative. Overall, the performance of the sensor was acceptable in our study, but we observed systematic variation between different users that also appeared to depend on the sample being tested. This highlights the need to improve user education especially regarding the effect of sampling, testing limitations in case of partially hydrolyzed, fractionated or fermented gluten and training users on how to perform the test in a way that gluten will be reliably detected

Influence of baking conditions on the extractability and immunochemical detection of wheat gluten proteins

Food processing conditions affect the accurate detection of gluten by ELISA, which is of importance for proper gluten-free labelling. We prepared different wheat flour-based and incurred baked goods (bread, crispbread, pretzel) to investigate the influence of baking conditions and alkali treatment on gluten quantitation by ELISA using different extraction solvents. Protein composition and extractability were determined (SDS-PAGE, RP-HPLC, GP-HPLC). The extraction solvents showed different performances; none of them could compensate the effect of baking on the detection. Dough preparation, baking and additional alkali treatment decreased protein extractability under reducing and non-reducing conditions. High temperature combined with alkali treatment resulted in the lowest protein extractabilities (<77% for bread crust, <61% for pretzel crust) due to the formation of disulfide and non-disulfide gluten crosslinks. There was no clear correlation between the protein composition and the extractability of alcohol- and SDS-soluble proteins of the baked goods. Thus, this research shows that gluten extractability rather than gluten composition is crucial for detection by ELISA in baked goods

Improvement of cake baking properties by lipases compared to a traditional emulsifier

Lipases are commonly used as clean-label improvers for bread. However, their potential use in cakes with different formulations remains unknown. The aim was to analyze the effects of seven baking lipases on three different cake formulations (an eggless cake, a pound cake with eggs and a yeast-based cake) in comparison to a traditional emulsifier. Product density, water loss during baking and product texture were assessed. If and to what extent the product quality was improved depended on both the lipase and the cake formulation. Lipase-induced effects mostly exceeded those of the emulsifier and were most pronounced in formulations without intrinsic emulsifiers like eggs. The lipases differed in their extent of improvement, hinting at the importance of their specific reactivity patterns and the resulting range of interactions with macromolecules. Further research is needed to unravel the mechanistic background of baking quality improvement in cakes

Lipases as cake batter improvers compared to a traditional emulsifier

Lipases can act on the baking quality of cakes as clean-label improvers. Only little is known about their possible effects on the batter quality of cakes. Especially the importance of the cake formulation has not been studied before. We therefore aim to analyse the effects of seven baking lipases on three different cake formulations (an eggless basic cake, a pound cake and a yeast-based cake) in comparison to the emulsifier DATEM (mono- and diacetyl tartaric acid esters of mono- and diglycerides of fatty acids). The impact on batter density, stickiness and rheological properties was examined. Both the lipase and the cake formulation had an influence on the extent of batter improvement. The greatest lipase-induced effects occurred in the eggless cake, probably because no intrinsic emulsifiers were present. Lipase reactions seemed to be inhibited in the yeast-based cake. For basic cake and pound cake, three lipases decreased batter density (up to 3.7%) and stickiness (up to 42.7%) and caused a liquefaction of the batter. This leads to an eased machinability of lipase-treated batters for cake manufacturing and opens up many possibilities for application of lipases in cakes and other fine bakery goods

Comparative characterization of baking lipase substrate specificities using emulsions and the p-nitrophenyl assay

For use in cakes, lipases with suitable substrate specificity are needed to minimize the release of short-chain fatty acids that cause undesirable off-flavors. We analyzed the substrate specificities of 17 lipases using the p-nitrophenyl (PNP)-assay. These results were compared to the reactions of the lipases with the baking fats rapeseed oil, margarine and butter in a new model emulsion. The free fatty acids (FFA) released from this model emulsion were quantitated by gas chromatography. The broad spectrum of lipase specificities seen in the PNP-assay was not apparent in the patterns of FFA released from the model emulsions. There, all lipases released similar percentages of FFA depending on the fat and emulsifier used. The prediction of lipase reactions via the PNP-assay should therefore be critically reevaluated for real food systems such as cakes

The Two Faces of Wheat

Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet

Chemistry of wheat gluten proteins: Quantitative composition

Background and Objectives Wheat is essential to secure nutrition for the world\u27s population. Its unique processing properties are largely determined by gluten protein content and composition. Findings Gluten proteins are subdivided into gluten protein types, α-, γ-, ω1,2-, and ω5-gliadins and high-molecular-weight glutenin subunits and low-molecular-weight glutenin subunits. The overall content and relative proportions of these types vary considerably depending on different genetic and environmental factors and mutual interactions. Conclusion This review summarizes the latest developments related to the chemistry of gluten and how species and variety, as well as soil type, weather conditions, atmospheric CO2 concentration, diseases, and fertilization with nitrogen, sulfur, phosphorus, potassium, and other minerals affect wheat gluten protein composition. Significance and Novelty Significant progress has been made to study the effect of different factors on gluten composition. However, comparisons between studies are almost impossible, because of the huge variability in experimental setups, environmental conditions and varieties studied. This calls for a need to develop common guidelines on how to set up experiments, on which parameters to investigate and on which procedure to use to improve comparability and reproducibility of the results

Chemistry of wheat gluten proteins: Qualitative composition

Background and Objectives Wheat gluten proteins make up one of the most complex protein aggregates in nature. Their qualitative and quantitative composition is determined by genetic and environmental factors as well as technological processes. Findings Gluten proteins comprise ω5-, ω1,2-, α-, and γ-gliadins as well as high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight (LMW) GS. About 50% of gluten proteins are monomeric gliadins with MWs from 28,000 to 55,000, while about 15% are present as disulfide-linked oligomeric proteins with MWs between 70,000 and 700,000, called HMW-gliadins. The remaining 35% are disulfide-linked polymeric glutenins with MWs from 700,000 to more than 10 million. Intrachain disulfide bonds, present in all types except ω-gliadins, stabilize the three-dimensional structure, while interchain disulfide bonds, mainly linking HMW-GS and LMW-GS, generate oligomers and polymers. Conclusions In this review, we provide an updated and detailed insight into the chemistry of wheat gluten proteins with a focus on the qualitative composition. Significance and Novelty An enhanced understanding of gluten protein structure and how it is affected will be essential to select and breed more resilient wheat varieties with favorable processing properties to help ensure nutrition and food security worldwide