Peptidomics analysis of in vitro digested wheat breads: Effect of genotype and environment on protein digestibility and release of celiac disease and wheat allergy related epitopes

Wheat proteins can trigger immunogenic reactions due to their resistance to digestion and immunostimulatory epitopes. Here, we investigated the peptidomic map of partially digested bread samples and the fingerprint of epitope diversity from 16 wheat genotypes grown in two environmental conditions. Flour protein content and composition were characterized; gastric and jejunal peptides were quantified using LC-MS/MS, and genotypes were classified into high or low bread protein digestibility. Differences in flour protein content and peptide composition distinguish high from low digestibility genotypes in both growing environments. No common peptide signature was found between high- and low-digestible genotypes; however, the celiac or allergen epitopes were noted not to be higher in low-digestible genotypes. Overall, this study established a peptidomic and epitope diversity map of digested wheat bread and provided new insights and correlations between weather conditions, genotypes, digestibility and wheat sensitivities such as celiac disease and wheat allergy.

Impact of varied tillage practices and phosphorus fertilization regimes on wheat yield and grain quality parameters in a five-year corn-wheat rotation system

Choosing appropriate tillage methods and applying the right amount of chemical fertilizers are pivotal for optimizing wheat management and enhancing wheat quality. This study investigated the influence of conservation agriculture and phosphorus levels on nutrient content, yield components, and quality traits of wheat in a corn-wheat rotation. Conducted over five years in field conditions, the study employed a randomized complete block design with tillage treatments (conventional tillage, CT; minimum tillage, MT; and no tillage, NT) and phosphorus levels (no fertilizer use, P0; and 100% fertilizer recommendation, PR) as factors. Soil samples were collected during the fourth year (2021-2022). Results revealed significant impacts of tillage methods and phosphorus levels on wheat straw and grain nutrient composition, yield components, and quality traits. Conventional tillage yielded the highest values for protein content (12%), Zeleny sedimentation volume (20.33 mL), hardness index (45), water absorption (64.12%), and wet gluten content (25.83%). Additionally, phosphorus fertilizer application positively influenced protein percentage, gluten weight, and gluten index. The study highlights the potential of strategic soil management, particularly conventional tillage combined with phosphorus fertilization, to enhance wheat quality and yield. By elucidating these relationships, the findings contribute to optimizing wheat cultivation practices and advancing the development of superior wheat cultivars for baking applications.

Bridging Nature and Engineering: Protein-Derived Materials for Bio-Inspired Applications

The sophisticated, elegant protein-polymers designed by nature can serve as inspiration to redesign and biomanufacture protein-based materials using synthetic biology. Historically, petro-based polymeric materials have dominated industrial activities, consequently transforming our way of living. While this benefits humans, the fabrication and disposal of these materials causes environmental sustainability challenges. Fortunately, protein-based biopolymers can compete with and potentially surpass the performance of petro-based polymers because they can be biologically produced and degraded in an environmentally friendly fashion. This paper reviews four groups of protein-based polymers, including fibrous proteins (collagen, silk fibroin, fibrillin, and keratin), elastomeric proteins (elastin, resilin, and wheat glutenin), adhesive/matrix proteins (spongin and conchiolin), and cyanophycin. We discuss the connection between protein sequence, structure, function, and biomimetic applications. Protein engineering techniques, such as directed evolution and rational design, can be used to improve the functionality of natural protein-based materials. For example, the inclusion of specific protein domains, particularly those observed in structural proteins, such as silk and collagen, enables the creation of novel biomimetic materials with exceptional mechanical properties and adaptability. This review also discusses recent advancements in the production and application of new protein-based materials through the approach of synthetic biology combined biomimetics, providing insight for future research and development of cutting-edge bio-inspired products. Protein-based polymers that utilize nature's designs as a base, then modified by advancements at the intersection of biology and engineering, may provide mankind with more sustainable products.

Alien introgression to wheat for food security: functional and nutritional quality for novel products under climate change

Crop yield and quality has increased globally during recent decades due to plant breeding, resulting in improved food security. However, climate change and shifts in human dietary habits and preferences display novel pressure on crop production to deliver enough quantity and quality to secure food for future generations. This review paper describes the current state-of-the-art and presents innovative approaches related to alien introgressions into wheat, focusing on aspects related to quality, functional characteristics, nutritional attributes, and development of novel food products. The benefits and opportunities that the novel and traditional plant breeding methods contribute to using alien germplasm in plant breeding are also discussed. In principle, gene introgressions from rye have been the most widely utilized alien gene source for wheat. Furthermore, the incorporation of novel resistance genes toward diseases and pests have been the most transferred type of genes into the wheat genome. The incorporation of novel resistance genes toward diseases and pests into the wheat genome is important in breeding for increased food security. Alien introgressions to wheat from e.g. rye and Aegilops spp. have also contributed to improved nutritional and functional quality. Recent studies have shown that introgressions to wheat of genes from chromosome 3 in rye have an impact on both yield, nutritional and functional quality, and quality stability during drought treatment, another character of high importance for food security under climate change scenarios. Additionally, the introgression of alien genes into wheat has the potential to improve the nutritional profiles of future food products, by contributing higher minerals levels or lower levels of anti-nutritional compounds into e.g., plant-based products substituting animal-based food alternatives. To conclude, the present review paper highlights great opportunities and shows a few examples of how food security and functional-nutritional quality in traditional and novel wheat products can be improved by the use of genes from alien sources, such as rye and other relatives to wheat. Novel and upcoming plant breeding methods such as genome-wide association studies, gene editing, genomic selection and speed breeding, have the potential to complement traditional technologies to keep pace with climate change and consumer eating habits.

Assessing the quality and grain yield of winter wheat in the organic farming management under wheat-legume intercropping practice

Intercropping is an alternative farming method that maximizes crop yield and resource usage effectiveness, especially in low-input agricultural systems. Legume-based intercropping systems can effectively boost the quality and wheat yield by promoting soil functions and microbial activities. However, changes in the types of legumes and field management can alter the response of crop functions. A three-year field study was conducted on intercropping cultivation of winter wheat variety (Butterfly and Lorien) and legume species (faba bean, incarnate clover, spring pea, winter pea) to assess grain yield and wheat quality in organic farming. Based on the results, Butterfly showed higher grain quality but lower grain yield and yield components than Lorien. Mixtures of legume crops with winter wheat did not significantly differ in wheat grain yield, but grain quality variables were significantly affected. Protein content (PC) was significantly higher in wheat and legume mixtures than in sole wheat by 4 %. PC in wheat + winter pea (Wheat + Wi) and wheat + faba bean (Wheat + Fa) were higher than wheat sown alone. Wet gluten (WG) was higher in Wheat + Wi than in sole wheat and wheat + incarnate clover mixtures (Wheat + In). The rheological parameters evaluated by the Mixolab showed greater wheat quality in Butterfly and legume mixtures. Mixed and row-row intercropping of wheat and legume species did not significantly influence rheological properties. To conclude, customizing wheat yield and grain quality under the effect of winter wheat and legume mixtures requires considering the optimal solution based on different cultivates, wheat varieties and legume species to achieve the desired response.

Artificial Rainfall on Grain Quality and Baking Characteristics of Winter Wheat Cultivars in Korea

Wheat (Triticum aestivum L.) stands as a significant cereal crop globally, including in Korea, where its consumption reached 35.7 kg per capita in 2023. In the southern regions of Korea, wheat cultivation follows paddy rice, with harvesting typically occurring during the rainy season in mid-June. This timing, coupled with the high humidity and unpredictable rainfall, often leads to pre-harvest sprouting and subsequent deterioration in flour quality. To assess the impact of rain on flour quality, an artificial rain treatment was administered 45 days after heading in an open field greenhouse, followed by flour quality analysis. The color measurement revealed an increase in the L* parameter, indicative of enhanced kernel vitreousness, attributed to endosperm starch degradation via alpha-amylase activation induced by water absorption. Moreover, significant changes were observed in ash content and the gluten index within the wetted group, resulting in decreased dough strength and stability, ultimately leading to a reduction in loaf volume. Consequently, it is recommended that wheat be harvested 4-7 days after reaching the physiological maturity stage to avoid the rainy season and ensure the production of high-quality wheat.

Research Advances in Superabsorbent Polymers

Superabsorbent polymers are new functional polymeric materials that can absorb and retain liquids thousands of times their masses. This paper reviews the synthesis and modification methods of different superabsorbent polymers, summarizes the processing methods for different forms of superabsorbent polymers, and organizes the applications and research progress of superabsorbent polymers in industrial, agricultural, and biomedical industries. Synthetic polymers like polyacrylic acid, polyacrylamide, polyacrylonitrile, and polyvinyl alcohol exhibit superior water absorption properties compared to natural polymers such as cellulose, chitosan, and starch, but they also do not degrade easily. Consequently, it is often necessary to modify synthetic polymers or graft superabsorbent functional groups onto natural polymers, and then crosslink them to balance the properties of material. Compared to the widely used superabsorbent nanoparticles, research on superabsorbent fibers and gels is on the rise, and they are particularly notable in biomedical fields like drug delivery, wound dressing, and tissue engineering.

A biobased binder of carboxymethyl cellulose, citric acid, chitosan and wheat gluten for nonwoven and paper

The amount of disposable nonwovens used today for different purposes have an impact on the plastic waste streams which is built up from several single-use products. A particular problem comes from nonwoven products with "hidden" plastic (such as cellulose mixed with synthetic fibers and/or plastic binders) where the consumers cannot see or expect plastic. We have here developed a sustainable binder based on natural components; wheat gluten (WG) and a polyelectrolyte complex (PEC) made from chitosan, carboxymethyl cellulose and citric acid which can be used with cellulosic fibers, creating a fully biobased nonwoven product. The binder formed a stable dispersion that improved the mechanical properties of a model nonwoven. With WG added, both the dry and the wet strength of the impregnated nonwoven increased. In dry-state, PEC increased the tensile index with >30 % (from 22.5 to 30 Nm/g), and with WG, with 60 % (to 36 Nm/g). The corresponding increase in the wet strength was 250 % (from 8 to 28 Nm/g) and 300 % (to 32 Nm/g). The increased strength was explained as an enrichment of covalent bonds (ester and amide bonds) established during curing at 170 °C, confirmed by DNP NMR and infrared spectroscopy.

Thermomechanical Stress Analysis of Hydrated Vital Gluten with Large Amplitude Oscillatory Shear Rheology

Vital gluten is increasingly researched as a non-food product for biodegradable materials. During processing, the protein network is confronted with increased thermal and mechanical stress, altering the network characteristics. With the prospect of using the protein for materials beyond food, it is important to understand the mechanical properties at various processing temperatures. To achieve this, the study investigates hydrated vital gluten under thermomechanical stress based on large amplitude oscillatory shear (LAOS) rheology. LAOS rheology was conducted at increasing shear strains (0.01-100%), various frequencies (5-20 rad/s) and temperatures of 25, 45, 55, 65, 70 and 85 °C. With elevating temperatures up to 55 °C, the linear viscoelastic moduli decrease, indicating material softening. Then, protein polymerization and the formation of new cross-links due to thermal denaturation cause more network connectivity, resulting in significantly higher elastic moduli. Beyond the linear viscoelastic regime, the strain-stiffening ratio rises disproportionately. This effect becomes even more evident at higher temperatures. Lacking a viscous contribution, the highly elastic but also stiff network shows less mechanical resilience. Additionally, at these elevated temperatures, structural changes during the protein's denaturation and network shrinkage due to water evaporation could be visualized with confocal laser scanning microscopy (CLSM).

The conformation of glutenin polymers in wheat grain: some genetic and environmental factors associated with this important characteristic

In a previous study we used asymmetric-flow field-flow fractionation to determine the polymer mass (Mw), gyration radius (Rw) and the polydispersity index of glutenin polymers (GPs) in wheat (Triticum aestivum). Here, using the same multi-location trials (4 years, 11 locations, and 192 cultivars), we report the factors that are associated with the conformation (Conf) of the polymers, which is the slope of Log(Rw) versus a function of Log(Mw). We found that Conf varied between 0.285 and 0.740, it had low broad-sense heritability (H2=16.8), and it was significantly influenced by the temperature occurring over the last month of grain filling. Higher temperatures were found to increase Rw and the compactness and sphericity of GPs. Alleles for both high- and low-molecular-weight glutenin subunits had a significant influence on the Conf value. Assuming a Gaussian distribution for Mw, the number of polymers present in wheat grains was computed for different kernel weights and protein concentrations, and it was found to exceed 1012 GPs per grain. Using atomic force microscopy and cryo-TEM, images of GPs were obtained for the first time. Under higher average temperature, GPs became larger and more spherical and consequently less prone to rapid hydrolysis. We propose some orientations that could be aimed at potentially reducing the impact of numerous GPs on people suffering from non-celiac gluten sensitivity.

Delineating the dynamic transformation of gluten morphological distribution, structure, and aggregation behavior in noodle dough induced by mixing and resting

To understand the formation of gluten network and its regulation on noodle qualities upon mixing and resting, the dynamic distribution and molecular transformation of gluten were tracked and quantified. Confocal laser scanning microscopy and scanning electron microscopy images showed that appropriate mixing (8 min) and resting (60 min) induced a compact gluten network with higher gluten junctions. Both height and width of protein molecular chains were increased by hydration during mixing and reduced after excessive resting (90 min). According to the size exclusion/reversed phase-HPLC profiles, mixing induced slight depolymerization of large glutenin polymer, and α-gliadin subunits were more susceptible to polymerization after appropriate mixing and resting. Increased mixing time was accompanied by the strengthening of ionic and hydrogen bonds, and the weakening of hydrophobic interaction. PCA and correlation analysis revealed the accurate regulation of mixing and resting induced dynamic distribution and evolution of gluten on the macroscopic noodle qualities.

Climate change effects on bread wheat phenology and grain quality: A case study in the north of Italy

Increasing temperatures, heat waves, and reduction of annual precipitation are all the expressions of climate change (CC), strongly affecting bread wheat (Triticum aestivum L.) grain yield in Southern Europe. Being temperature the major driving force of plants' phenological development, these variations also have effects on wheat phenology, with possible consequences on grain quality, and gluten protein accumulation. Here, through a case study in the Bolognese Plain (North of Italy), we assessed the effects of CC in the area, the impacts on bread wheat phenological development, and the consequences on grain gluten quality. The increasing trend in mean annual air temperature in the area since 1952 was significant, with a breakpoint identified in 1989, rising from 12.7 to 14.1°C, accompanied by the signals of increasing aridity, i.e., increase in water table depth. Bread wheat phenological development was compared in two 15-year periods before and after the breakpoint, i.e., 1952-1966 (past period), and 2006-2020 (present period), the latest characterized by aridity and increased temperatures. A significant shortening of the chronological time necessary to reach the main phenological phases was observed for the present period compared to the past period, finally shortening the whole life cycle. This reduction, as well as the higher temperature regime, affected gluten accumulation during the grain-filling process, as emerged analyzing gluten composition in grain samples of the same variety harvested in the area both before and after the breakpoint in temperature. In particular, the proportion of gluten polymers (i.e., gliadins, high and low molecular weight glutenins, and their ratio) showed a strong and significant correlation with cumulative growing degree days (CGDDs) accumulated during the grain filling. Higher CGDD values during the period, typical of CC in Southern Europe, accounting for higher temperature and faster grain filling, correlated with gliadins, high molecular weight glutenins, and their proportion with low molecular weight glutenins. In summary, herein reported, data might contribute to assessing the effects of CC on wheat phenology and quality, representing a tool for both predictive purposes and decision supporting systems for farmers, as well as can guide future breeding choices for varietal innovation.

Clustering and cross-linking of the wheat storage protein α-gliadin: A combined experimental and theoretical approach

Our aim was to understand mechanisms for clustering and cross-linking of gliadins, a wheat seed storage protein type, monomeric in native state, but incorporated in network while processed. The mechanisms were studied utilizing spectroscopy and high-performance liquid chromatography on a gliadin-rich fraction, in vitro produced α-gliadins, and synthetic gliadin peptides, and by coarse-grained modelling, Monte Carlo simulations and prediction algorithms. In solution, gliadins with α-helix structures (dip at 205 nm in CD) were primarily present as monomeric molecules and clusters of gliadins (peaks at 650- and 700-s on SE-HPLC). At drying, large polymers (R_g 90.3 nm by DLS) were formed and β-sheets increased (14% by FTIR). Trained algorithms predicted aggregation areas at amino acids 115-140, 150-179, and 250-268, and induction of liquid-liquid phase separation at P- and Poly-Q-sequences (Score = 1). Simulations showed that gliadins formed polymers by tail-to-tail or a hydrophobic core (Kratky plots and R_ee = 35 and 60 for C- and N-terminal). Thus, the N-terminal formed clusters while the C-terminal formed aggregates by disulphide and lanthionine bonds, with favoured hydrophobic clustering of similar/exact peptide sections (synthetic peptide mixtures on SE-HPLC). Mechanisms of clustering and cross-linking of the gliadins presented here, contribute ability to tailor processing results, using these proteins.

Versatile wheat gluten: functional properties and application in the food-related industry

Gluten is a key component that allows wheat flour to form a dough, and it is also a byproduct of the production of wheat starch. As a commercial product, wheat gluten is increasingly used in the food-related industry because of its versatile functional properties and wide range of sources. Wheat gluten is manufactured industrially on a large scale through the Martin process and batter process and variants thereof. Gliadin and glutenin impart cohesiveness and elasticity properties, respectively, to wheat gluten. The formation of gluten networks and polymers depends mainly on covalent bonds (disulfide bonds) and noncovalent bonds (ionic bonds, hydrogen bonds, and hydrophobic interactions). The multifunctional properties (viscoelasticity, gelation, foamability, etc.) of wheat gluten are shown by rehydration and other processing techniques. Wheat gluten has been widely used in wheat-based products, food auxiliary agents, food packaging, encapsulation and release of food functional ingredients, food adsorption and heat insulation materials, special purpose foods, and versatile applications. In the future, wheat gluten protein will be used as an important raw material to participate in the development and preparation of various food and degradable materials, and the application potential of wheat gluten in food-related industries will be massive. This review summarizes the main manufacturing processes, composition, and structure of gluten protein, and the various functional properties that support its application in the food and related industries.

Innovative Green Way to Design Biobased Electrospun Fibers from Wheat Gluten and These Fibers’ Potential as Absorbents of Biofluids

In this study, a new method was developed to successfully design sustainable microfibers from wheat gluten proteins using a nonreducing solvent and electrospinning. We explored the morphology by X-ray tomography, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM), protein chemistry and cross-linking by size exclusion-high-performance liquid chromatography (SE-HPLC), and secondary structure by Fourier transform infrared spectroscopy (FT-IR) of fibers containing 15 and 20% of gluten. The impact of heat (130 °C) post-treatment on the polymerization properties of fibers and their absorption performance in different biofluids were also evaluated. The fibers with 20% gluten showed a uniform architecture supported by a relatively stronger fibrous network as compared to irregular and brittle fibers from 15% gluten. Heat treatment of fibers increased the protein cross-linking in all electrospun fibers as compared to the non-heat-treated fibers, as evidenced by SE-HPLC. An increase in the amount of α-helices and random coils was observed in the proteins of all of the heat-treated fibers compared to the nontreated fibers by FT-IR. This suggested that the heat treatment contributed positively to the gluten protein's chemical rearrangements, e.g., aggregation, new hydrogen and isopeptide bonding, and conversion of some of the sulfhydryl groups into disulfide cross-links, contributing positively to the functional performance. The heat-treated electrospun fibers with 20% gluten showed a very attractive blood absorption capacity (323%) and reasonable stability in phosphate-buffered saline (PBS) buffer compared to 15% gluten fibers and non-heat-treated fibers. Cotton-like fiber architecture, high blood absorption capacity, and reasonable stability in PBS buffer are properties desired for absorbents of biofluids and should be further explored in healthcare and medical applications.

Chain Terminators and Glutathione Weaken Wheat Dough under Excess Nitrogen Input

An excessive nitrogen (N) supply may weaken dough due to an imbalance between N and sulfur (S) in the grains. However, the mechanism underlying the weakening effect of excessive N supply has yet to be fully elucidated. In this study, we evaluated the effect of the N rate × S rate interaction on the ratio of N to S (N/S ratio), grain protein concentration, amount and composition of protein fractions, and dough properties of a bread wheat cultivar. The concentrations of glutathione and modified gliadins with an odd number of cysteine residues (potential chain terminators for glutenins) were also examined. The results revealed that the weakening effect of excess N input is closely associated with an increased gliadin/glutenin ratio, reduced low-molecular-weight glutenin subunit concentrations, and the degree of polymerization of glutenin. More importantly, we found that the increased concentrations of glutathione and chain terminators in grains are involved in the modification of the polymerization degree in glutenins.

Improvements of dried noodles qualities using two-stage resting: Explanation from macro and micro perspectives

The purpose of this study was to elucidate the effects of two-stage resting (dough crumbs and dough sheets resting) on the quality of dried noodles. An improvement mechanism was explored according to the texture of dough sheets, gluten network, and microstructure of cooked noodles. After two-stage resting, the extensibility of dough sheets, the contents of glutenin macro polymer (GMP), and disulfide bonds (S-S) increased significantly (p < .05), whereas the content of sulphydryl group (-SH) significantly declined. From the perspective of microstructure, the average length and width of dough sheets protein experienced a significant reduction (p < .05); however, the branching rate, the number of protein lines, and the total length of the protein lines significantly increased (p < .05). Furthermore, the average network line length and width of cooked noodles were significantly reduced as the branching rate rose (p < .05); meanwhile, the number of holes significantly increased while the average area significantly decreased (p < .05). Overall, the two-stage resting has improved the quality of dried noodles and contributed to a more uniform and compact gluten network distribution.

Phenocave: An Automated, Standalone, and Affordable Phenotyping System for Controlled Growth Conditions

Controlled plant growth facilities provide the possibility to alter climate conditions affecting plant growth, such as humidity, temperature, and light, allowing a better understanding of plant responses to abiotic and biotic stresses. A bottleneck, however, is measuring various aspects of plant growth regularly and non-destructively. Although several high-throughput phenotyping facilities have been built worldwide, further development is required for smaller custom-made affordable systems for specific needs. Hence, the main objective of this study was to develop an affordable, standalone and automated phenotyping system called "Phenocave" for controlled growth facilities. The system can be equipped with consumer-grade digital cameras and multispectral cameras for imaging from the top view. The cameras are mounted on a gantry with two linear actuators enabling XY motion, thereby enabling imaging of the entire area of Phenocave. A blueprint for constructing such a system is presented and is evaluated with two case studies using wheat and sugar beet as model plants. The wheat plants were treated with different irrigation regimes or high nitrogen application at different developmental stages affecting their biomass accumulation and growth rate. A significant correlation was observed between conventional measurements and digital biomass at different time points. Post-harvest analysis of grain protein content and composition corresponded well with those of previous studies. The results from the sugar beet study revealed that seed treatment(s) before germination influences germination rates. Phenocave enables automated phenotyping of plants under controlled conditions, and the protocols and results from this study will allow others to build similar systems with dimensions suitable for their custom needs.

Changes of aggregation and structural properties of heat-denatured gluten proteins in fast-frozen steamed bread during frozen storage

The aim of this research was to clearly clarify the deterioration mechanism of heat-denatured gluten proteins by exploring the change of aggregation and structural characteristics of heat-denatured gluten proteins in the steamed bread system and the steamed gluten system during frozen storage. An increase in the total SDS-soluble protein content was determined, which mainly attributed to the soluble monomer protein content increased. Combined with the significant increase of free sulfhydryl, from 3.12 μmol/g to 5.06 μmol/g and 2.64 μmol/g to 3.29 μmol/g, respectively, it can be inferred that the proteins depolymerization induced by frozen storage was mainly involved in the breakdown of heat-induced glutenin-gliadin disulfide cross-linking. Frozen storage induced the conversion of random coil structure to β-sheet structure and a ruptured microstructure with small fragment was observed. Moreover, the protein of steamed bread system was easier to depolymerize than that of the steamed gluten system.

Expression of seed storage proteins responsible for maintaining kernel traits and wheat flour quality in common wheat under heat stress conditions

Heat stress during grain filling has been documented to decrease wheat grain yield and quality in arid regions worldwide. We studied the effect of heat stress on wheat flour quality in heat tolerant cultivars to define the effects of heat stress on flour quality and to identify germplasm combining traits for heat tolerance and good flour quality. We studied the kernel phenotypic traits, the expression of seed storage proteins (SSPs), and the resulting flour quality under heat and normal conditions. Under heat stress, all cultivars yielded narrow-shaped seeds, and increased protein contents as compared to the control plants grown under normal conditions. The specific sedimentation values used to estimate the gluten quality varied between cultivars. We identified cultivars that could maintain good flour quality under heat stress conditions: 'Imam', which possessed the Glu-D1d allele responsible for the suitable bread-making; 'Bohaine', which displayed high expression level of SSPs; and 'Condor', which possessed slight variations in the ratio of each SSP under heat stress conditions. Combining the desirable traits from these cultivars could yield a wheat cultivar with heat tolerance and good flour quality.

Enzymatic modifications of gluten protein: Oxidative enzymes

Oxidative enzymes treat weak flours in order to restore the gluten network of damaged wheat flour and reduce the economic and technological losses. The present review concentrates on oxidative exogenous enzymes (transglutaminase, laccase, glucose oxidase, hexose oxidase) and oxidative endogenous enzymes (tyrosinase, peroxidase, catalase, sulfhydryl oxidase, lipoxygenase, lipase, protein disulfide isomerase, NAD(P)H-dependent dehydrogenase, thioredoxin reductase and glutathione reductase) and their effects on the rheological, functional, and conformational features of gluten and its subunits. Overall, transglutaminase is used in wheat-based foods through introducing isopeptide bonds (ε-γ glutamyl-lysine). Glucose oxidase, hexose oxidase, peroxidase, sulfhydryl oxidase, lipase, and lipoxygenase form disulfide and nondisulfide bonds through producing hydrogen peroxide. Laccase, tyrosinase, and protein disulfide isomerase form cross-links between tyrosine and cysteine residues by generating radicals. Thioredoxin reductase and glutathione reductase create new inter disulfide bonds. The effect of oxidative enzymes on the formation of covalent cross-linkages were substantially more than non-covalent bonds in gluten structure.

Effect of grape seed power on the structural and physicochemical properties of wheat gluten in noodle preparation system

Noodles were prepared using wheat flour supplemented with 1%, 3%, and 5% grape seed power (GSP). The farinograph properties of wheat flour, the textural properties of the dough, and thermal properties of the gluten were determined. The microstructure was analyzed by scanning electron and atomic force microscopy, and the effects of the addition of GSP on the physicochemical and structural properties (free sulfhydryl content, surface hydrophobic region, and secondary structure) of wheat gluten protein were analyzed. 1% GSP promoted the aggregation of gluten proteins by promoting hydrophobic interactions and hydrogen bonding, thus enhanced the noodle quality. Whereas, 3% and 5% GSP addition disrupted the disulfide bonds between gluten protein molecules and formed macromolecular aggregates linked to gluten proteins through non-covalent bonds and hydrophobic interactions, which prevented the formation of the gluten protein reticulation structure. Our study emphasized the interaction between wheat proteins and GSP in noodle making dough.

Effects of thermal properties and behavior of wheat starch and gluten on their interaction: A review

Starch and gluten, the most important macromolecules in wheat flour, vary in thermal properties. The thermal behavior of starch, gluten and their complexes during the manufacture and quality control of flour products need to be accurately understood. However, the high complexity of starch-gluten systems impedes the accurate description of their interactions. When heated within varying temperature ranges and when water molecules are involved, the behaviors of amylose and amylopectin change, and the properties of the starch are modified. Moreover, important indicators of starch granules such as gelatinization temperature, peak viscosity, and so on, which are encapsulated by the gluten matrix, are altered. Meanwhile, the high-temperature environment induces the opening of the intrachain disulfide bonds of gliadin, leading to an increase in the probability of interchain disulfide bond formation in the gluten network system. These behaviors are notable and may provide insights into this complex interaction. In this review, the relationship between the thermal behavior of wheat starch and gluten and the quality of flour products is analyzed. Several methods used to investigate the thermal characteristics of wheat and its flour products are summarized, and some thermal interaction models of starch and gluten are proposed.

Meat analogs: Protein restructuring during thermomechanical processing

Increasing awareness of inefficient meat production and its future impact on global food security has led the food industry to look for a sustainable approach. Meat products have superior sensorial perception, because of their molecular composition and fibrous structure. Current understanding in the science of food structuring has enabled the utilization of alternative or nonmeat protein ingredients to create novel structured matrices that could resemble the textural functionality of real meat. The physicochemical and structural changes that occur in concentrated protein systems during thermomechanical processing lead to the creation of a fibrous or layered meat-like texture. Phase transitions in concentrated protein systems during protein-protein, protein-polysaccharide, protein-lipid, and protein-water interactions significantly influence the texture and the overall sensory quality of meat analogs. This review summarizes the roles of raw materials (moisture, protein type and concentration, lipids, polysaccharides, and air) and processing parameters (temperature, pH, and shear) in modulating the behavior of the protein phase during the restructuring process (structure-function-process relationship). The big challenge for the food industry is to manufacture concept-based (such as beef-like, chicken-like, etc.) meat analogs with controlled structural attributes. This information will be useful in developing superior meat analogs that fulfill consumer expectations when replacing meat in their diet.

Differences in Processing Quality Traits, Protein Content and Composition between Spelt and Bread Wheat Genotypes Grown under Conventional and Organic Production

The unique rheological properties of bread wheat dough and the breadmaking quality of its flour are the main factors responsible for the global distribution and utilization of wheat. Recently, interest in the production and expansion of spelt wheat has been boosted due to its significance in the production of healthy food, mostly originated from organic production. The aim of this study was to examine and compare quality parameters (gluten content, Zeleny sedimentation volume, farinograph dough properties), protein content and composition (by the Dumas method, Size Exclusion (SE) and Reversed Phase (RP) High Performance Liquid Chromatography (HPLC) analyses) of five bread and five spelt wheat varieties grown under conventional and organic production in Hungary and under conventional production in Serbia. Most of the analyzed traits showed significant differences between varieties, wheat species and growing sites. Total protein content was significantly higher in spelt than in bread wheat and under conventional than under organic production. In comparison to spelt, bread wheat showed better breadmaking quality, characterized by a higher amount of glutenins (in particular high molecular weight glutenin subunits) and unextractable polymeric proteins. The proportion of the gliadins was also found to be different under conventional and organic systems. Spelt Ostro and Oberkulmer-Rotkorn and bread wheat varieties Balkan, Estevan and Pobeda proved suitable for low input and organic systems.

Protein based packaging of plant origin: Fabrication, properties, recent advances and future perspectives

Huge plastic waste is receiving worldwide attention nowadays due to its resistance to degradation and toxicity on environmental components including humans. Improper disposal of plastics affect the food chain and compromise various activities of aquatic life. Each facet of the plastic waste problem requires a significant attention and compels its elimination from the environment due to its ecologically deleterious threats. Therefore, this problem of plastic pollution and issues related thereof merits an attention regarding the alternatives wherein biopolymer based packaging has a potential role to play. This line of research has received a renewed focus where biodegradable films are being developed from proteins which are obtained from animals (include fish myofibrillar protein, collagen, gelatine, etc), and plants especially graminacea (rice, wheat, maize, barley etc), leguminaceae (soya beans, pea, etc.), asteraceae (sunflower) but little attention has been paid towards the potential of aquatic plants for development of packaging material. The present review provides a comprehensive account of biodegradable films developed from plant proteins viz. soy protein, wheat gluten, corn zein and sunflower protein as emerging supplement to plastics. Moreover, this article also tip-offs the potential of macrophytes for fabrication of protein based packaging films incorporated with bioactive materials extracted from macrophytes.

Glutenin and Gliadin, a Piece in the Puzzle of their Structural Properties in the Cell Described through Monte Carlo Simulations

Gluten protein crosslinking is a predetermined process where specific intra- and intermolecular disulfide bonds differ depending on the protein and cysteine motif. In this article, all-atom Monte Carlo simulations were used to understand the formation of disulfide bonds in gliadins and low molecular weight glutenin subunits (LMW-GS). The two intrinsically disordered proteins appeared to contain mostly turns and loops and showed "self-avoiding walk" behavior in water. Cysteine residues involved in intramolecular disulfide bonds were located next to hydrophobic peptide sections in the primary sequence. Hydrophobicity of neighboring peptide sections, synthesis chronology, and amino acid chain flexibility were identified as important factors in securing the specificity of intramolecular disulfide bonds formed directly after synthesis. The two LMW-GS cysteine residues that form intermolecular disulfide bonds were positioned next to peptide sections of lower hydrophobicity, and these cysteine residues are more exposed to the cytosolic conditions, which influence the crosslinking behavior. In addition, coarse-grained Monte Carlo simulations revealed that the protein folding is independent of ionic strength. The potential molecular behavior associated with disulfide bonds, as reported here, increases the biological understanding of seed storage protein function and provides opportunities to tailor their functional properties for different applications.

Diverse Wheat-Alien Introgression Lines as a Basis for Durable Resistance and Quality Characteristics in Bread Wheat

Wheat productivity has been significantly improved worldwide through the incorporation of novel genes from various gene pools, not least from wild relatives of wheat, into the commonly cultivated bread and durum wheat. Here, we present and summarize results obtained from a diverse set of wheat-alien introgression lines with mainly introgressions of rye, but also of Leymus spp. and Thinopyrum junceiforme into bread-wheat (Triticum aestivum L.). From this material, lines carrying 2RL were found with good agronomic performance and multiple resistance not least towards several races of powdery mildew. A novel resistance gene, one of few showing resistance towards all today identified stem rust races, designated Sr59, was also found originating from 2RL. Lines with multiple introgressions from 4R, 5R, and 6R were found resistant towards the majority of the stripe rust races known today. Due to lack of agricultural adaptation in these lines, transfer of useful genes into more adapted wheat material is a necessity, work which is also in progress through crosses with the CSph1b mutant, to be able to only transfer small chromosome segments that carry the target gene. Furthermore, resistance towards Russian wheat aphid was found in lines having a substitution of 1R (1D) and translocations of 3DL.3RS and 5AL.5RS. The rye chromosomes 1R, 2R, and 6R were found responsible for resistance towards the Syrian Hessian fly. High levels of especially zinc was found in several lines obtained from crosses with Leymus racemosus and Leymus mollis, while also some lines with 1R, 2R, or 5R showed increased levels of minerals and in particular of iron and zinc. Moreover, lines with 1R, 2R, 3R, and Leymus spp. introgressions were also found to have a combination of high iron and zinc and low cadmium concentrations. High variation was found both in grain protein concentration and gluten strength, measured as %UPP, within the lines, indicating large variation in bread-making quality. Thus, our study emphasizes the impact that wheat-alien introgression lines can contribute to current wheat lines and shows large opportunities both to improve production, resistance, and quality. To obtain such improvements, novel plant breeding tools, as discussed in this paper, opens unique opportunities, to transfer suitable genes into the modern and adapted wheat cultivars.

Genetic and Environmental Factors Associated to Glutenin Polymer Characteristics of Wheat

The polymers of wheat glutenins are studied here using asymmetric flow field flow fractionation (A4F). Molecular mass (Mw), gyration radius (Rw), and the polydispersity index (PI) of polymers were measured over a four-year, multi-local wheat trial in France. The experiment, involving 11 locations and 192 cultivars, offered the opportunity to approach the genetic and environmental factors associated with the phenotypic values of the polymer characteristics. These characteristics, which were all highly influenced by environmental factors, exhibited low broad-sense heritability coefficients and were not influenced by grain protein content and grain hardness. The 31 alleles encoding the glutenin subunits explained only 17.1, 25.4, and 16.8% of the phenotypic values of Mw, Rw, and PI, respectively. The climatic data revealed that a 3.5 °C increase between locations of the daily average temperature, during the last month of the grain development, caused an increase of more than 189%, 242%, and 434% of the Mw, Rw, and PI, respectively. These findings have to be considered in regard to possible consequences of global warming and health concerns assigned to gluten. It is suggested that the molecular characteristics of glutenins be measured today, especially for research addressing non-celiac gluten sensitivity (NCGS).

Genomic and functional genomics analyses of gluten proteins and prospect for simultaneous improvement of end-use and health-related traits in wheat

KEY MESSAGE

Recent genomic and functional genomics analyses have substantially improved the understanding on gluten proteins, which are important determinants of wheat grain quality traits. The new insights obtained and the availability of precise, versatile and high-throughput genome editing technologies will accelerate simultaneous improvement of wheat end-use and health-related traits. Being a major staple food crop in the world, wheat provides an indispensable source of dietary energy and nutrients to the human population. As worldwide population grows and living standards rise in both developed and developing countries, the demand for wheat with high quality attributes increases globally. However, efficient breeding of high-quality wheat depends on critically the knowledge on gluten proteins, which mainly include several families of prolamin proteins specifically accumulated in the endospermic tissues of grains. Although gluten proteins have been studied for many decades, efficient manipulation of these proteins for simultaneous enhancement of end-use and health-related traits has been difficult because of high complexities in their expression, function and genetic variation. However, recent genomic and functional genomics analyses have substantially improved the understanding on gluten proteins. Therefore, the main objective of this review is to summarize the genomic and functional genomics information obtained in the last 10 years on gluten protein chromosome loci and genes and the cis- and trans-factors regulating their expression in the grains, as well as the efforts in elucidating the involvement of gluten proteins in several wheat sensitivities affecting genetically susceptible human individuals. The new insights gathered, plus the availability of precise, versatile and high-throughput genome editing technologies, promise to speed up the concurrent improvement of wheat end-use and health-related traits and the development of high-quality cultivars for different consumption needs.