Improvements in the qualities of gluten-free bread after using a protease obtained from Aspergillus oryzae

Microbial proteases and their applications

Proteases (proteinases or peptidases) are a class of hydrolases that cleave peptide chains in proteins. Endopeptidases are a type of protease that hydrolyze the internal peptide bonds of proteins, forming shorter peptides; exopeptidases hydrolyze the terminal peptide bonds from the C-terminal or N-terminal, forming free amino acids. Microbial proteases are a popular instrument in many industrial applications. In this review, the classification, detection, identification, and sources of microbial proteases are systematically introduced, as well as their applications in food, detergents, waste treatment, and biotechnology processes in the industry fields. In addition, recent studies on techniques used to express heterologous microbial proteases are summarized to describe the process of studying proteases. Finally, future developmental trends for microbial proteases are discussed.

Evaluation of producing gluten-free bread by utilizing amaranth and lipase and protease enzymes

Generating high pleasant and nutritious gluten-free (GF) bread for sufferers with celiac disease (CD) is a main task for food technologists. Amaranth is a useful nutrition and gliadin-free and could be utilized in GF products. At this study, by using different substitutions of amaranth flour (0%, 15%, 25%) GF bread samples were produced, and the effects of lipase and protease enzymes as bread improver have been investigated. On this assessment, physicochemical (ash, moisture, specific volume, bread yield, color index and porosity) and rheological (springiness, chewiness, cohesiveness, hardness and staling) characteristic, microstructure and sensory feature of bread were evaluated. The consequences tested the production bread with acceptable sensory properties is feasible with the aid of applying amaranth flour in GF bread formulations. Applying 15% amaranth flour increased meaningfully bread porosity and specific volume, but texture hardness was notably decreased. 25% amaranth flour formulation lowered hardness, specific volume and porosity of bread samples. Utilizing lipase and protease enzymes in 15% amaranth flour reduced texture hardness, porosity and specific volume, while the enzymes at 25% amaranth flour heightened the mentioned bread properties. In this result, for lower amaranth flour substitution (15%), using enzymes in formulation is not necessary, however enzymes in 25% Amaranth flour substitution could promote bread texture, porosity and specific volume.

Nutritional and bioactive characteristics of buckwheat, and its potential for developing gluten-free products: An updated overview

In the present era, food scientists are concerned about exploiting functional crops with nutraceutical properties. Buckwheat is one of the functional pseudocereals with nutraceutical components used in the treatment of health-related diseases, malnutrition, and celiac diseases. As a preferred diet as a gluten-free product for celiac diseases, buckwheat is a good source of nutrients, bioactive components, phytochemicals, and antioxidants. The general characteristics and better nutritional profile of buckwheat than other cereal family crops were highlighted by previous investigations. In buckwheats, bioactive components like peptides, flavonoids, phenolic acids, d-fagomine, fagopyritols, and fagopyrins are posing significant health benefits. This study highlights the current knowledge about buckwheat and its characteristics, nutritional constituents, bioactive components, and their potential for developing gluten-free products to target celiac people (1.4% of the world population) and other health-related diseases.

Effective Use of Plant Proteins for the Development of "New" Foods

Diversity in our diet mirrors modern society. Affluent lifestyles and extended longevity have caused the prevalence of diabetes and sarcopenia, which has led to the increased demand of low-carb, high-protein foods. Expansion of the global population and Westernization of Asian diets have surged the number of meat eaters, which has eventually disrupted the supply–demand balance of meat. In contrast, some people do not eat meat for religious reasons or due to veganism. With these multiple circumstances, our society has begun to resort to obtaining protein from plant sources rather than animal origins. This “protein shift” urges food researchers to develop high-quality foods based on plant proteins. Meanwhile, patients with food allergies, especially gluten-related ones, are reported to be increasing. Additionally, growing popularity of the gluten-free diet demands development of foods without using ingredients of wheat origin. Besides, consumers prefer “clean-label” products in which products are expected to contain fewer artificial compounds. These diversified demands on foods have spurred the development of “new” foods in view of food-processing technologies as well as selection of the primary ingredients. In this short review, examples of foodstuffs that have achieved tremendous recent progress are introduced: effective use of plant protein realized low-carb, high protein, gluten-free bread/pasta. Basic manufacturing principles of plant-based vegan cheese have also been established. We will also discuss on the strategy of effective development of new foods in view of the better communication with consumers as well as efficient use of plant proteins.

Changes in physicochemical properties of rice flour by fermentation with koji and its potential use in gluten-free noodles

To use rice flour as an ingredient in gluten-free noodles, improved texture properties such as increased hardness and reduced adhesiveness are required. We investigated the physicochemical characteristics of rice flour obtained by fermenting japonica rice with koji, determined the pasting and textural properties of the resulting gel, and suggested a method for producing gluten-free noodles. Koji-fermented rice flour was obtained by fermenting rice grains for 24 and 48 h. Koji fermentation reduced the protein and ash content of the rice and lowered the pH. The change in amylose content was not significant, but the short-to-long-chain ratio of amylopectin increased. Changes in the structural and compositional characteristics facilitated swelling of the rice flour and starch leaching. Variations in the gelatinization and hydration properties of the rice flour increased its peak viscosity and gel hardness, and reduced its gel adhesiveness. Noodles made from koji-fermented rice flour have improved physical features, such as modified textural properties resulting from a gel texture and increased whiteness, indicating that koji-fermented rice flour is a desirable noodle ingredient for gluten-free foods.

Methods for the Modification and Evaluation of Cereal Proteins for the Substitution of Wheat Gluten in Dough Systems

The substitution of wheat gluten in the food industry is a relevant research area because the only known treatment for celiac disease is abstinence from this protein complex. The use of gluten-free cereals in dough systems has demonstrated that the viscoelastic properties of gluten cannot be achieved without the modification of the protein fraction. The quality of the final product is determined by the ability of the modification to form a matrix similar to that of gluten and to reach this, different methods have been proposed and tested. These procedures can be classified into four main types: chemical, enzymatic, physical, and genetic. This article provides a comprehensive review of the most recent research done in protein modification of cereal and pseudocereals for gluten substitution. The reported effects and methodologies for studying the changes made with each type of modification are described; also, some opportunity areas for future works regarding the study of the effect of protein modifications on gluten-free products are presented.

A Systematic Review of Gluten-Free Dough and Bread: Dough Rheology, Bread Characteristics, and Improvement Strategies

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 replacement is still the major challenge in the development of doughs and baked goods. The literature documents various improvement strategies. The most active approach seeks to identify alternative ingredients that can mimic the viscoelastic properties of the gluten network, notably hydrocolloids, enzymes, emulsifiers, and alternative sources of protein. However, other innovative strategies, such as high pressure, using heat to dry flour, and sourdough fermentation, have been investigated. In this context, the first aim of this review is to summarize current knowledge regarding gluten-free doughs, breads, and bakery products. Secondly, as it is clear that the manufacture of gluten-free products remains a key challenge, it suggests some improvement strategies that can boost their nutritional, technological, and sensorial characteristics.

Commercial Saccharomyces cerevisiae as a starter culture in "Wanergao": A traditional fermented food in China

To explore the effect of commercial Saccharomyces cerevisiae on the quality of traditional "Wanergao" for reasonable consuming guidance, the dominant microbes, physicochemical property, free amino acid content, texture, and sensory properties during fermentation of "Wanergao" were illustrated in this paper. Compared with the samples in the control group, "Wanergao" samples in the two groups that were subjected to S. cerevisiae inoculation had weaker acidity (the pH values dropped from 4.39 ± 0.08 to 4.36 ± 0.07 and 4.36 ± 0.07 within 2 h during fermentation), higher fermenting rate (volume increased from 100 ± 1.31 to 305 ± 4.61 and 316 ± 4.93 mL separately within 3 h), and the dominant lactic acid bacteria and yeast being leukonid and S. cerevisiae. More amylose, ethanol, and free amino acid were detected in "Wanergao" produced with S. cerevisiae inoculation compared with "Wanergao" produced by sourdough. The two kinds of "Wanergao" presented various hardness (2318 ± 112, 2279 ± 103), springiness (0.76 ± 0.03, 0.71 ± 0.03), chewiness (1.43 ± 0.05, 1.41 ± 0.06), and cohesiveness (0.68 ± 0.03, 0.62 ± 0.03) after fermentation. The result of sensory analysis revealed that "Wanergao" in the S. cerevisiae group had higher elasticity, aroma, and restoring force. The experiment demonstrated that "Wanergao" produced by using S. cerevisiae is a kind of fermented rice product with rich fragrance, high amount of nutrients, and strong elasticity.

The effect of Quinoa flour and enzymes on the quality of gluten-free bread

Gluten-free products usually are produced by refined flours such as rice and corn flour, which the bran is separated during processing. These flours are not nutritionally as rich as gluten containing products. Moreover, gluten-free bread has several technical problems such as unfavorable texture, low volume, quick staling, and weaker color and taste compared with the wheat flour products. In this research, gluten-free bread with various substitution of quinoa (0%, 15%, and 25%) was produced and the effects of lipase and protease enzymes on the quality of bread were investigated. The gluten-free bread properties like physicochemical properties, rheological properties, and bread microstructure were evaluated. Moreover, the sensorial properties were assessed. The results have demonstrated that gluten-free bread with quinoa flour has favorable properties. Also, lipase and protease enzymes could improve the quality of the bread containing quinoa. Protease and lipase enzymes increased the bread volume, specifically in sample containing 15% quinoa substitution. Moreover, the staling was delayed in sample 25% quinoa substitution. The bread was accepted by consumers, and the highest score belonged to 25% substitution of quinoa flour.

Recent practical researches in the development of gluten-free breads

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.

Gluten-Free Products for Celiac Susceptible People

The gluten protein of wheat triggers an immunological reaction in some gluten-sensitive people with HLA-DQ2/8 genotypes, which leads to Celiac disease (CD) with symptomatic damage in the small intestinal villi. Glutenin and gliadin are two major components of gluten that are essentially required for developing a strong protein network for providing desired viscoelasticity of dough. Many non-gluten cereals and starches (rice, corn, sorghum, millets, and potato/pea starch) and various gluten replacers (xanthan and guar gum) have been used for retaining the physical-sensorial properties of gluten-free, cereal-based products. This paper reviews the recent advances in the formulation of cereal-based, gluten-free products by utilizing alternate flours, starches, gums, hydrocolloids, enzymes, novel ingredients, and processing techniques. The pseudo cereals amaranth, quinoa, and buckwheat, are promising in gluten-free diet formulation. Genetically-modified wheat is another promising area of research, where successful attempts have been made to silence the gliadin gene of wheat using RNAi techniques. The requirement of quantity and quality for gluten-free packaged foods is increasing consistently at a faster rate than lactose-free and diabetic-friendly foods. More research needs to be focused on cereal-based, gluten-free beverages to provide additional options for CD sufferers.

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

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.

Dynamic viscoelasticity of protease-treated rice batters for gluten-free rice bread making

Papain (cysteine protease), subtilisin (Protin SD-AY10, serine protease), and bacillolysin (Protin SD-NY10, metallo protease) increased the specific volume of gluten-free rice breads by 19-63% compared to untreated bread. In contrast, Newlase F (aspartyl protease) did not expand the volume of the rice bread. In a rheological analysis, the viscoelastic properties of the gluten-free rice batters also depended on the protease categories. Principal component analysis (PCA) analysis suggested that the storage and loss moduli (G' and G″, respectively) at 35 °C, and the maximum values of G' and G″, were important factors in the volume expansion. Judging from the PCA of the viscoelastic parameters of the rice batters, papain and Protin SD-AY10 improved the viscoelasticity for gluten-free rice bread making, and Protin SD-NY effectively expanded the gluten-free rice bread. The rheological properties differed between Protin SD-NY and the other protease treatments.

Calcium in Gluten-Free Life: Health-Related and Nutritional Implications

Calcium deficiency and metabolic bone diseases are a frequent co-morbidity of coeliac disease (CD). Gluten-free diet (GFD) is the only effective treatment of CD. However, CD patients on the strict GFD consume less than the recommended amounts of calcium. In this review, the main etiological factors responsible for calcium deficiency in CD were presented. Additionally, the research on the application of calcium supplements in the gluten-free breadmaking was reviewed, and its effect on the technological and sensory properties of baked products was indicated. Calcium-fortified gluten-free products could increase the calcium content in the diet of CD patients, supplying the amount of calcium they need for prophylactic or therapeutic use. Apart from this, the consumption of the naturally GF products as well as functional ingredients beneficially affecting calcium absorption need to be encouraged.

Techno-functional and nutritional performance of commercial breads available in Europe

In recent years, the growing interest for well-being and healthy lifestyle together with an increasing awareness of the close relationship between food and health have boosted the production of an increasing number of novel goods to be placed in both gluten-containing and gluten-free products market. The objective of this study was to provide a realistic and detailed overview of the current bread-market supply in order to evaluate the overall quality of the available offer in this prioritized food industry area. Twenty commercial breads consisting of gluten (n = 10) and gluten-free (n = 10) samples currently available in the European market have been assessed by physical-chemical, technological, nutritional, and sensory determinations. The quality parameters obtained were related to each other by using Pearson correlations, while sample classification was achieved by applying factor analysis. Higher values for protein and bio-accessible polyphenols content, aroma and taste quality, and low and moderate expected glycaemic index corresponded to gluten containing breads. Although the main distinction was between gluten and gluten-free samples as it was expected, classification of breads allowed differentiating samples with different formulations in terms of presence/absence of alternative, innovative, and nutrient-dense raw materials.

Understanding gluten-free dough for reaching breads with physical quality and nutritional balance

In the last decade the development of gluten-free foodstuffs has attracted great attention as a result of better diagnoses of coeliac disease and a greater knowledge of the relationship between gluten-free products and health. The increasing interest has prompted extensive research into the development of gluten-free foodstuffs that resemble gluten-containing foods. This review aims to provide some insights on dough functionality and process conditions regarding bread quality and to point out recent research dealing with the nutritional composition of those products. Gluten-free dough results from the combination of different ingredients, additives, and the processing aids required for building up network structures responsible for bread quality. Some relationships between dough rheology and bread characteristics were established to identify possible predictor parameters. Regarding bread-making processes, the impact of mixing, dough treatment and baking is stated. Nutritional quality is an important asset when developing gluten-free breads, and different strategies for improving it are reviewed. Gluten-free bread quality is dependent on ingredients and additives combination, but also processing can provide a way to improve bread quality. Nutritive value of the gluten-free breads must be always in mind when setting up recipes, for obtaining nutritionally balanced bread with adequate glycaemic index.

Ongoing applicative studies of plant thioredoxins

Studies triggered by the discovery of the function of thioredoxin (Trx) in photosynthesis have revealed its role throughout biology. Parallel biochemical and proteomic analyses have led to the identification of its numerous putative targets. Recently, to verify the biological significance of these targets, in vivo studies using transformants in which Trx is overexpressed or suppressed are in progress, and the transformants themselves that are being used in such studies show their potential applicative values. Moreover, Trx's mitigation of allergenicity for some proteins offers promising prospects in the food industry. Practical studies based on redox regulation, once only on the horizon, are now achieving new dimensions. This short review focuses on the industrial applications of Trx studies, the current situation, and future perspectives. The putative targets obtained by the proteomics approach in comparison with in vivo observations of the transformants are also examined. Applicative studies of glutathione, a counterpart of Trx, are also discussed briefly.