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The purpose of this study was to investigate the effects of different structures of corn starch (high amylose corn starch, normal corn starch, and waxy corn starch) on the processing quality of dough. The rheological properties, thermal properties, microstructure and physicochemical properties of gluten proteins in the simulated dough of corn starch were determined. The results showed that the viscoelasticity of the high-amylose corn starch mock dough was significantly higher than that of the normal/waxy cornstarch mock dough, which was attributed to its non-gelatinization and highly filling characteristics. Waxy corn starch significantly inhibited the thermal aggregation of gluten proteins through competitive water absorption, resulting in a relatively loose structure of the dough after heat treatment. The results of molecular weight distribution and intermolecular interactions also confirmed that waxy corn starch mainly inhibited the formation of high molecular weight gluten proteins by hindering the crosslinking of disulfide bonds, leading to the transition of gluten proteins from a rigid α-helix to a disordered β-turn structure. This study helps to gain a deeper understanding of the interaction mechanism between starch and gluten proteins, and provides a reference for improving the processing quality of flour products by regulating the structural characteristics of starch.

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BACKGROUND RESULTS CONCLUSION Arabinoxylan is commonly used as a hydrocolloid in frozen dough to improve the texture and the sensory qualities of the products. The effects of vinegar residue arabinoxylan (VRAX) on the secondary structures and microstructures of gluten proteins during freeze–thaw storage were studied, and the underlying mechanism governing these effects was clarified.The results revealed that VRAX improved the textural properties of gluten proteins, but had a negative impact on their viscoelasticity. Additionally, the addition of VRAX increased the number of disulfide bonds and also improved the freezing tolerance of the gluten proteins. It was found that the enthalpy of the gluten proteins decreased by 19.78% following VRAX addition. As a result of the use of VRAX, the freezing procedure resulted in reduced formation of ice crystals, protecting the gluten network structure and preserving the dough's elasticity. The network structure of gluten proteins after VRAX treatment was more ordered and integrated relative to that of frozen blank control gluten proteins.Overall, the freeze–thaw stability of the gluten proteins was enhanced by VRAX. These results suggest that VRAX has potential as an effective cryoprotectant in frozen dough. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Nitrogen fertiliser is the major input and cost for wheat production, being required to support the development of the canopy to maximise yield and for the synthesis of the gluten proteins that are necessary for breadmaking. Consequently, current high‐yielding cultivars require the use of nitrogen fertilisation levels above the yield optimum to achieve the grain protein content needed for breadmaking. This study aimed to reduce this requirement by identifying traits that allow the use of lower levels of nitrogen fertiliser to produce wheat for breadmaking. Results: A range of commercial wheat genotypes (cultivars) were grown in multiple field trials (six sites over 3 years) in the UK with optimal (200 kg Ha‐1) and suboptimal (150 kg Ha‐1) application of nitrogen. Bulked grain samples from four sites per year were milled and white flours were baked using three types of breadmaking process. This identified five cultivars that consistently exhibited good breadmaking quality when grown with the lower nitrogen application. Chemical and biochemical analyses showed that the five cultivars were characterised by exhibiting grain protein deviation (GPD) and high dough elasticity. Conclusions: It is possible to develop novel types of wheat that exhibit good breadmaking quality by selecting for GPD and high dough strength. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aegilops umbellulata (UU) is a wheat wild relative that has potential use in the genetic improvement of wheat. In this study, 46 Ae. umbellulata accessions were investigated for stripe rust resistance, heading date (HD), and the contents of iron (Fe), zinc (Zn), and seed gluten proteins. Forty-two of the accessions were classified as resistant to stripe rust, while the other four accessions were classified as susceptible to stripe rust in four environments. The average HD of Ae. umbellulata was significantly longer than that of three common wheat cultivars (180.9 d vs. 137.0 d), with the exception of PI226500 (138.9 d). The Ae. umbellulata accessions also showed high variability in Fe (69.74–348.09 mg kg–1) and Zn (49.83–101.65 mg kg–1) contents. Three accessions (viz., PI542362, PI542363, and PI554399) showed relatively higher Fe (230.96–348.09 mg kg–1) and Zn (92.46–101.65 mg kg–1) contents than the others. The Fe content of Ae. umbellulata was similar to those of Ae. comosa and Ae. markgrafii but higher than those of Ae. tauschii and common wheat. Aegilops umbellulata showed a higher Zn content than Ae. tauschii, Ae. comosa, and common wheat, but a lower content than Ae. markgrafii. Furthermore, Ae. umbellulata had the highest proportion of γ-gliadin among all the species investigated (Ae. umbellulata vs. other species=mean 72.11% vs. 49.37%; range: 55.33–86.99% vs. 29.60–67.91%). These results demonstrated that Ae. umbellulata exhibits great diversity in the investigated traits, so it can provide a potential gene pool for the genetic improvement of these traits in wheat.

In order to realize the resource utilization of peony stamens, the effects of peony stamen protein on the texture, dynamic rheological properties, disulfide bonds, surface microstructure and secondary structure of dough and gluten proteins were studied using soybean protein isolate (SPI) as a reference. The results showed that peony stamen protein could significantly improve the hardness, stickiness and chewiness of dough, and the effect of addition of less than 6% of peony stamen protein was more pronounced than that of SPI. Addition of peony stamen protein increased the storage and loss moduli and consequently the viscoelasticity of dough. The effect of peony stamen protein on the formation of gluten protein network structure was basically the same as that of SPI. Under scanning electron microscopy (SEM), gluten proteins added with 6% of peony stamen protein exhibited a compact network structure consisting of many deep pores. In the presence of peony stamen protein, the total proportion of the relative stable secondary structures of α-helix and β-sheet reached the maximum value of 59.32%, and the content of disulfide bonds increased by 89% compared with the blank group. In conclusion, peony stamen protein can effectively promote the formation of gluten protein network structure and improve the quality of dough, and therefore can be used in the production of flour products with high viscoelasticity requirements.

The salty enzymatic hydrolysate of wheat gluten was desalted and fractionated into four fractions (F1–F5). F4, which had the highest salty taste and proportion of peptides with molecular mass below 1 000 Da among these fractions, was further fractionated by Sephadex G-15 gel filtration chromatography into five subfractions (P1–P5). Among these subfractions, P2 was found to have the highest content of salty peptides and the strongest salty taste. By liquid chromatography tandem mass spectrometry (LC-MS/MS), the amino acid sequences of P2 were identified as PFGQQ, PFSPQ, QPFP, PDFP and FDDP, with molecular masses of 576.28, 575.28, 488.25, 475.22 and 493.21 Da, respectively. The results provide a theoretical basis for the development of salty peptides from gluten protein.

Gluten proteins are known as immunological triggers for inflammation resulting in mucosal lesions in patients with coeliac disease (CD). Adherence to a strict gluten-free diet (GFD) is currently known as the only effective treatment for CD. In this study, we performed a systematic review and dose-response meta-analysis on data from previous studies to investigate the association between different gluten doses administered and the risk of CD relapse. Electronic databases were systematically searched to retrieve studies that investigated the response of CD patients to different amounts of gluten intake and evaluated the clinical, serologic, and/or histologic evidence to recognize disease relapse. Study-specific relative risks (RRs) were combined using a random effects model. A total of 440 identified published papers were screened, of which 7 records were selected following full-text reviewing and eligibility assessment for dose-response meta-analysis. According to our analysis, the risk of CD relapse is estimated to be 0.2% (RR: 1.002; 95% CI: 1.001 to 1.004) following the consumption of 6 mg gluten/day, which was increased to 7% (RR: 1.07; 95% CI: 1.03 to 1.10), 50% (RR: 1.50; 95% CI: 1.23 to 1.82), 80% (RR: 1.80; 95% CI: 1.36 to 2.38), and 100% (RR: 2.00; 95% CI: 1.43 to 2.78) by the daily intake of 150, 881, 1276, and 1505 mg gluten, respectively. Although good adherence to a GFD can adequately control CD-related symptoms, disease relapse might happen even with a very low dose of gluten, and the duration of exposure to gluten is also an important matter. The current literature has substantial limitations, such as relying on the data from just a few countries that were different in terms of the amount of gluten administered, the duration of the challenge, etc. Therefore, more randomized clinical trials using a standardized gluten challenge protocol are needed to confirm the findings of the present study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gluten-rich fractions isolated from miller's bran increased the bread loaf volume. • Gluten-rich sub-aleurone cells were the main source of these fractions. • Sub-aleurone gluten proteins were functionally comparable to flour gluten proteins. • Isolating gluten by dry rather than wet fractionation could boost its functionality. • Gluten isolation after air classification could enrich gluten-hindering components. The residual endosperm of wheat miller's bran is rich in gluten proteins due to the presence of protein-rich sub-aleurone cells. Here, the goal was to gain insight into the bread-making functionality of sub-aleurone gluten-enriched fractions obtained through dry fractionation of miller's bran and the inherent bread-making functionality of sub-aleurone gluten. Therefore, two sub-aleurone gluten-enriched fractions (Sub-al F and Sub-al C), differing in particle size distribution and chemical composition, were prepared from miller's bran using impact milling, sieving, and air classification. Substituting 22.5% of white flour with Sub-al F , Sub-al C , commercial gluten A (GluA) and B (GluB), all standardised to a protein content of 20.6 % with wheat starch, led to an increase in specific loaf volume of 14.8%, 14.0%, 14.3%, and 21.8%, respectively. Despite their higher level of bran contamination and lower relative gluten content, Sub-al F and Sub-al C were equally functional as commercial gluten (GluA). This could be due to wet fractionation, which is used in commercial gluten production, reducing the functionality of gluten, as indicated by comparing the functionality of gluten in Sub-al C and gluten isolated via wet fractionation from Sub-al C with GluA. Substituting 6% of white flour with gluten isolated via wet fractionation from Sub-al C and from the corresponding flour increased the specific volume by 27.2% and 29.4%, respectively. Sub-aleurone gluten and flour gluten were, hence, functionally comparable. In conclusion, the sub-aleurone's high content of functional gluten enables the production of functional gluten-enriched ingredients from miller's bran. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wheat gluten proteins serve as the largest protein molecules in nature and play key roles in breadmaking quality formation. In this study, we used a pair of Glu-A1 allelic variation lines to perform a comprehensive investigation on the effects of Glu-A1a encoded 1Ax1 subunit on gluten physicochemical properties, molecular structures and breadmaking quality. The results showed that the presence of the 1Ax1 subunit significantly increased gluten content, leading to marked improvement of dough rheological properties. Meanwhile, gluten physicochemical properties such as foaming ability and foaming stability, oil/water-holding capacity, emulsifying activity, disulfide bond content, and gluten degradation temperature were significantly improved. A confocal laser scanning microscope analysis revealed that the 1Ax1 subunit drastically enhanced gluten microstructure. Gluten secondary structure analysis by Fourier transform infrared spectroscopy and laser scanning microscope-Raman spectroscopy indicated that 1Ax1 subunit significantly promoted β-turn and β-sheet content and reduced α-helix content. Three-dimensional structure analysis by AlphaFold2 revealed a similar structural feature of 1Ax1 with the superior quality subunit 1Ax2*. Correlation and principal component analyses demonstrated that α-helix and β-sheet content had a significant correlation with dough rheological properties, gluten physicochemical properties and breadmaking quality. Our results showed that 1Ax1 subunit positively affected gluten molecular structure and quality formation. • 1Ax1 improved dough rheological properties and gluten physicochemical properties. • Connectivity and uniformity of gluten microstructure were enhanced by 1Ax1 subunit. • The 1Ax1 subunit promoted gluten disulfide bond content and foaming properties. • Loaf volume and inner structures were positively affected by the 1Ax1 subunit. • α-Helix and β-sheet were the key predictors for gluten strength and breadmaking quality. [ABSTRACT FROM AUTHOR]

To advance the industrialization production of steamed buns, the current study explored the freeze-stability of unfermented, pre-fermented and par-steamed frozen dough. The results showed that the steamed bun made from unfermented dough with 2.0% yeast, the pre-fermented dough with a pre-fermented time of 30 min and the par-steamed dough with a pre-steamed time of 15 min showed the best sensory properties quality upon frozen storage. The gassing power of un- and pre-fermented dough gradually decreased, and dough with longer pre-fermented time exhibited more evident loss of gassing power. Freeze-induced depolymerization of gluten protein was the least distinct in the par-steamed dough, followed by the pre- and un-fermented dough, which was probably related to the superior freeze stability of glutenin-gliadin macro-crosslinks upon the pre-steaming stage. The surface hydrophobicity of gluten proteins of frozen dough decreased during the initial storage and was enhanced subsequently, which was related with the combined effects of the unfolding and synchronous aggregation induced by freezing and steaming, respectively. Moreover, the surface hydrophobicity of gluten in par-steamed frozen dough and steamed buns was more resistant to frozen storage, which was probably attributed to the established stable structure during the pre-steaming process. [ABSTRACT FROM AUTHOR]

Celiac disease (CD) is a small intestinal inflammatory condition where consumption of gluten induces a T-cell mediated immune response that damages the intestinal mucosa in susceptible individuals. CD affects at least 1% of the world’s population. The increasing prevalence of CD has been reported over the last few decades. However, the reason for this increase is not known so far. Certain factors such as increase in awareness and the development of advanced and highly sensitive diagnostic screening markers are considered significant factors for this increase. Wheat breeding strategies, fertilizers, and pesticides, particularly herbicides, are also thought to have a role in the increasing prevalence. However, less is known about this issue. In this review, we investigated the role of these agronomic practices in depth. Our literature-based results showed that wheat breeding, use of nitrogen-based fertilizers, and herbicides cannot be solely responsible for the increase in celiac prevalence. However, applying nitrogen fertilizers is associated with an increase in gluten in wheat, which increases the risk of developing celiac-specific symptoms in gluten-sensitive individuals. Additionally, clustered regularly interspaced short palindromic repeats (CRISPR) techniques can edit multiple gliadin genes, resulting in a low-immunogenic wheat variety that is safe for such individuals.

The quality traits of dough and dry pasta obtained from semolina (Triticum durum Desf. var. Biensur), harvested from a 13.6 ha field, subjected to variable-rate nitrogen (N) fertilization, were assessed to test site-specific pasta production for a short supply chain. Based on the grain quality spatial distribution, two distinct areas with protein content lower or higher than 13% were delineated and harvested selectively. The rheological properties of semolina samples obtained from those areas were evaluated. Furthermore, dry pasta was produced and characterized for its cooking behaviour and sensory characteristics. Semolina was demonstrated to have rheological characteristics (i.e., gluten aggregation time and energy, as evaluated by GlutoPeak test) positively related to the protein content as well as the related pasta, showing better cooking quality. These results are driven by the high amounts of gluten proteins, as well as by the glutenin/gliadin ratio, which are indicators of the technological quality of semolina. Overall, the results indicate that segregation of the grain with >13% of protein at harvest led to the production of semolina with a higher gluten protein content and a higher glutenin/gliadin ratio and, hence, to the production of pasta with better cooking quality. Therefore, site-specific pasta could be a potential asset for a short supply chain, aiming at improving traceability, as well as environmental and economic sustainability. [ABSTRACT FROM AUTHOR]

To improve the stability of anthocyanins and techno-functionality of purple and blue wheat, the selectively hydrolyzed soy protein (reduced glycinin, RG) and β-conglycinin (7S) were prepared and their enhanced effects were comparatively investigated. The anthocyanins in purple wheat showed higher stability compared to that of the blue wheat during breadmaking. The cyanidin-3-O-glucoside and cyanidin-3-O-rutincoside in purple wheat and delphinidin-3-O-rutinoside and delphinidin-3-O-glucoside in blue wheat were better preserved by RG. Addition of RG and 7S enhanced the quality of steamed bread made from colored and common wheat, with RG exhibited a more prominent effect. RG and 7S suppressed the gelatinization of starch and improved the thermal stability. Both RG and 7S promoted the unfolding process of gluten proteins and facilitated the subsequent crosslinking of glutenins and gliadins by disulfide bonds. Polymerization of α- and γ-gliadin into glutenin were more evidently promoted by RG, which contributed to the improved steamed bread quality. [Display omitted] • Anthocyanins in purple wheat showed higher stability than that of the blue wheat. • Reduced glycinin (RG) was superior to β -conglycinin (7S) in anthocyanin stabilization. • Steamed bread quality made from whole colored wheat was improved by RG and 7S. • RG and 7S suppressed starch gelatinization and improved thermal stability of starch. • Polymerization of α -and γ-gliadin into glutenins were more evidently promoted by RG. [ABSTRACT FROM AUTHOR]

Wheat miller's bran negatively affects the gluten network but contains the grain tissue with the highest gluten content, the sub-aleurone. Here, the aim was to investigate how sub-aleurone gluten proteins in miller's bran affect bran-enriched bread quality. A bread-making experiment was performed with six lab-scale-produced bran samples. These strongly differed in protein content (10.8-18.6%) but had a similar particle size ( d 50 : 1266-1330 μm) and strong water retention capacity (0.71-0.80 mL of H 2 O/g). Bran protein content variation mainly originated from sub-aleurone protein content variation (10.7-26.2%). Incorporating the bran with the highest versus lowest sub-aleurone protein content increased the loaf volume by 22.4%. 99% of loaf volume variation could be explained by sub-aleurone protein content variation. Conclusively, sub-aleurone protein content is the most important factor regarding bran functionality in bread-making. This was strengthened using commercial bran. Therefore, bran selection based on (sub-aleurone) protein content could be a low-cost, low-effort opportunity for bran-enriched bread-making.

Celiac disease (CD) is a small intestinal inflammatory condition where consumption of gluten induces a T-cell mediated immune response that damages the intestinal mucosa in susceptible individuals. CD affects at least 1% of the world's population. The increasing prevalence of CD has been reported over the last few decades. However, the reason for this increase is not known so far. Certain factors such as increase in awareness and the development of advanced and highly sensitive diagnostic screening markers are considered significant factors for this increase. Wheat breeding strategies, fertilizers, and pesticides, particularly herbicides, are also thought to have a role in the increasing prevalence. However, less is known about this issue. In this review, we investigated the role of these agronomic practices in depth. Our literature-based results showed that wheat breeding, use of nitrogen-based fertilizers, and herbicides cannot be solely responsible for the increase in celiac prevalence. However, applying nitrogen fertilizers is associated with an increase in gluten in wheat, which increases the risk of developing celiac-specific symptoms in gluten-sensitive individuals. Additionally, clustered regularly interspaced short palindromic repeats (CRISPR) techniques can edit multiple gliadin genes, resulting in a low-immunogenic wheat variety that is safe for such individuals. [ABSTRACT FROM AUTHOR]

Wheat's sub-aleurone is rich in gluten but mainly ends up in the miller's bran fraction during milling. Here, the goal was to investigate dry processing to fractionate miller's bran into a functional fraction enriched in sub-aleurone gluten proteins and hence gain fundamental insight into the behaviour of miller's bran and sub-aleurone during dry processing. Impact milling and sieving of miller's bran yielded a sub-aleurone-enriched fraction (27.4% mass yield, 22.4% protein, 63.2% starch) and starchy endosperm-poor fraction enriched in dietary fibre (62.6% mass yield; 27.4% arabinoxylan). The ash and phytate contents of the sub-aleurone-enriched fraction are higher than those of the corresponding flour because of (limited) aleurone cell opening during the impact milling. Subsequent pin disc milling, and air classification of the sub-aleurone-enriched fraction resulted in a sub-aleurone gluten-enriched fraction. This fraction had a protein content of 31.4%, an absolute gluten content of 24.5% and lower arabinoxylan content per unit protein than flour. The production of a sub-aleurone-enriched fraction through impact milling and sieving of miller's bran presents an opportunity to increase the flour yield in industrial mills. Additionally, the sub-aleurone gluten-enriched fraction offers a promising alternative to commercial gluten. Nowadays, commercial gluten is manufactured through energy-intensive wet processing methods. Furthermore, also the starchy endosperm-poor fraction could serve as an ingredient enriched in dietary fibre. In conclusion, this study contributes to increasing resource efficiency in the wheat manufacturing industry by repurposing a by-product of wheat milling. [Display omitted] • Impact milling and sieving miller's bran generated a sub-aleurone-rich fraction. • Air classifying the sub-aleurone-rich fraction yielded a protein-rich fraction. • The protein-rich fraction (31.4% dw) had a relative gluten content of 78.0%. • The protein-rich fraction had a lower AX content per unit protein than flour. • Aleurone cell opening led to proportionally higher mineral and phytate contents. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of starch with varying degree of debranching on the rheological, thermal, and structural properties of heat-induced gluten gel. As the duration of starch debranching treatment increased from 0 to 8 h, the viscoelasticity of the gel containing debranched starch (DBS) improved. Compared with the gluten gel (G), the gel strength of the G + DBS (8 h) sample increased by 65.2 %. The degradation temperature of gluten was minimally affected by DBS, while the weight loss rate increased by 4.4 %. Furthermore, the α-helical structure of gluten decreased, concomitant with an increase in β-sheet content. Notably, DBS treated for 8 h exhibited more hydrogen bonds with the tyrosine of gluten and triggered disulfide bridge conformation to transition from g-g-g to t-g-g, thereby reducing the stability of the molecular conformation of gluten proteins, as evidenced by the decreased height and width of the molecular chains observed in atomic force microscopy images. Overall, the composite gel structure induced by DBS exhibited a more continuous and homogeneous owing to the improved compatibility between DBS and gluten proteins, favoring the formation of a robust gel. These findings provide valuable insights for utilizing DBS to enhance gluten gel properties. [Display omitted] • The strength of gluten gel was improved by debranched starch (DBS). • Highly DBS generated a microstructure compatible with gluten, and improved gel texture. • DBS decreased α-helical in gluten and destabilized S S bridges. • DBS hindered the cross-linking of gliadin or low molecular weight glutenin. • The aggregation of gluten molecular chains at the nanoscale was inhibited by DBS. [ABSTRACT FROM AUTHOR]

This study investigated the effect of sodium carboxymethyl cellulose (CMC) addition to breadcrumbs. Oil absorption, moisture content and quality characteristics of breadcrumbs were measured, changes in microstructure after frying were analyzed using scanning electron microscopy (SEM), and the effects of CMC addition on the physicochemical properties and structure of wheat gluten proteins were analyzed. Our results showed that the addition of 1.5% CMC reduced the oil absorption of breadcrumb samples from 19.80% to 11.39%. Additionally, the crispiness of the breadcrumbs increased from 21,405.33 to 33,978.09 g/s, while the whiteness value improved from 40.35 to 43.81. Furthermore, CMC incorporated breadcrumb samples had lower bound water content and experienced less water loss during frying which was accompanied by the denser microstructure. The activity of gluten proteins was also determined, the results showed that at 1.5% CMC, surface hydrophobicity reduced from 1952.36 to 1173.66, sulfhydryl content decreased from 1.15 to 0.88, and β-folding declined from 26.76 to 25.78. These changes suggest that CMC, being a hydrophilic colloid, enhanced the hydrophilic ability of the breadcrumbs. The incorporation of CMC into breadcrumbs appears to be a promising strategy for reducing oil absorptivity and improving the overall quality of the breadcrumbs. [Display omitted] • 1.5% CMC reduced the oil absorption rate of the breadcrumbs samples from 19.80% to 11.39%. • After CMC addition, crispiness and whiteness value were improved. • CMC incorporated breadcrumbs samples had lower bound water content and denser microstructure. • At 1.5% CMC, surface hydrophobicity, sulfhydryl content, and β-folding declined. • CMC, being a hydrophilic colloid, enhanced the hydrophilic ability of the breadcrumbs. [ABSTRACT FROM AUTHOR]

The quality traits of dough and dry pasta obtained from semolina (Triticum durum Desf. var. Biensur), harvested from a 13.6 ha field, subjected to variable-rate nitrogen (N) fertilization, were assessed to test site-specific pasta production for a short supply chain. Based on the grain quality spatial distribution, two distinct areas with protein content lower or higher than 13% were delineated and harvested selectively. The rheological properties of semolina samples obtained from those areas were evaluated. Furthermore, dry pasta was produced and characterized for its cooking behaviour and sensory characteristics. Semolina was demonstrated to have rheological characteristics (i.e., gluten aggregation time and energy, as evaluated by GlutoPeak test) positively related to the protein content as well as the related pasta, showing better cooking quality. These results are driven by the high amounts of gluten proteins, as well as by the glutenin/gliadin ratio, which are indicators of the technological quality of semolina. Overall, the results indicate that segregation of the grain with >13% of protein at harvest led to the production of semolina with a higher gluten protein content and a higher glutenin/gliadin ratio and, hence, to the production of pasta with better cooking quality. Therefore, site-specific pasta could be a potential asset for a short supply chain, aiming at improving traceability, as well as environmental and economic sustainability.

To advance the industrialization production of steamed buns, the current study explored the freeze-stability of unfermented, pre-fermented and par-steamed frozen dough. The results showed that the steamed bun made from unfermented dough with 2.0% yeast, the pre-fermented dough with a pre-fermented time of 30 min and the par-steamed dough with a pre-steamed time of 15 min showed the best sensory properties quality upon frozen storage. The gassing power of un- and pre-fermented dough gradually decreased, and dough with longer pre-fermented time exhibited more evident loss of gassing power. Freeze-induced depolymerization of gluten protein was the least distinct in the par-steamed dough, followed by the pre- and un-fermented dough, which was probably related to the superior freeze stability of glutenin-gliadin macro-crosslinks upon the pre-steaming stage. The surface hydrophobicity of gluten proteins of frozen dough decreased during the initial storage and was enhanced subsequently, which was related with the combined effects of the unfolding and synchronous aggregation induced by freezing and steaming, respectively. Moreover, the surface hydrophobicity of gluten in par-steamed frozen dough and steamed buns was more resistant to frozen storage, which was probably attributed to the established stable structure during the pre-steaming process.

Summary: Incorporating high level of potato flour into wheat flour enhances nutritional values of bread but induces a series of problems that lead to the decline of the bread quality. To overcome the barrier, wheat gluten and carboxymethylcellulose (CMC) were added into potato–wheat composite flour to improve dough machinability and bread quality. The rheological properties, thermo‐mechanical properties and microstructures of dough were investigated. The results showed that the interaction between gluten and CMC mitigated the discontinuity of gluten matrix and gluten protein aggregation caused by the addition of potato flour, which yielded a more branched and compact gluten network. The compact three‐dimensional viscoelastic structure induced improvements of gas retention capacity and dough stability, making it mimic the machinability properties of wheat flour dough. Bread qualities were apparently improved with the combined use of 4% gluten and 6% CMC, of which specific volume increased by 42.86%, and simultaneously, hardness reduced by 75.93%. [ABSTRACT FROM AUTHOR]

Herein, we investigated the effects of gluten proteins (Pr) on the structure, physicochemical properties, and in vitro digestibility of wheat starch-lauric acid (WS-LA) complexes under various cooking methods (steaming, boiling, and baking). There was no ternary complex formation between WS, LA, and Pr in the samples after different cooking methods. Scanning electron microscopy (SEM) and fluorescence microscopy showed variation in size, structure and distribution of WS-LA of WS-LA-Pr samples after cooking. An increase in the intensity of V-type diffraction peak and thermal stability was observed in steamed and baked samples, however, opposite trend was noticed in boiled sample. Additionally, a higher 1022/995 cm−1 absorbance ratio was noted in WS-LA-Pr sample treated with boiling than other cooking methods. Further, in vitro resistance to enzymatic hydrolysis was improved in samples treated with steaming and baking compared with boiled treated samples. In sum, this study may offer a thorough understanding on how these interactions take place during food processing, to optimize the production and development of new food products with desired microstructure and functionality features. [Display omitted] [ABSTRACT FROM AUTHOR]

Absract: The interaction between gluten and hydrocolloid additive, as well as the pH condition during dough formation is very important in making flour products. In this study, the influence of different pH conditions on the interactions between gluten proteins (including glutenin and gliadin) and carboxymethylcellulose (CMC), and on the rheological and microstructure changes of gluten proteins was investigated. The dynamic frequency sweep indicated CMC‐gluten displayed more solid‐like behavior under alkaline conditions than that under acidic conditions. The creep‐recovery experiment suggested acidic conditions were not conducive to maintain the elasticity of CMC‐gluten. Microstructural changes of various glutens with CMC showed that a higher ratio of β‐sheets was observed in the CMC‐gluten and CMC‐glutenin under alkaline conditions. Total free sulfhydryl contents and changes in tryptophan microenvironment showed glutenin played a key role in the G polymerization with the addition of CMC. Lower surface hydrophobicity of CMC‐gluten was displayed under acidic conditions. Scanning electron microscopy images showed that neutral and alkaline conditions were conducive to the network structure formation of CMC‐gluten and CMC‐glutenin. Practical Application: This study investigated the interaction of CMC with gluten, gluten, and gliadin under different pH conditions, providing a basis for expanding dough quality improvement, and extending the in‐depth application of CMC in the food industry. [ABSTRACT FROM AUTHOR]

Recent studies suggested that gliadin proteins from the ancient diploid einkorn wheat Triticum monococcum retained a reduced number of immunogenic peptides for celiac disease patients because of a high in vitro digestibility with respect to hexaploid common wheat. In this study, we compared the immunological properties of gliadins from two Triticum monococcum cultivars (Hammurabi and Norberto-ID331) with those of a Triticum durum cultivar (Adamello). Gliadins were digested by mimicking the in vitro gastrointestinal digestion process that includes the brush border membrane peptidases. Competitive ELISA, based on R5 monoclonal antibody, showed that gastrointestinal digestion reduced the immunogenicity of Triticum monococcum gliadins; conversely, the immunogenic potential of Triticum durum gliadins remained almost unchanged by the in vitro digestion. The immune stimulatory activity was also evaluated by detecting the IFN-γ production in gliadin-reactive T-cell lines obtained from the small intestinal mucosa of HLA-DQ2+ celiac disease patients. Interestingly, gastrointestinal digestion markedly reduced the capability of Triticum monococcum gliadins (p

Temperature and nitrogen (N) availability are two important environmental factors that may produce important changes in grain composition during grain filling of bread wheat. In this study, four wheat lines with the down-regulation of gliadins by means of RNA interference (RNAi) have been characterized to determine the effect of thermal stress and N availability on grain weight and quality; with focus on gliadin and glutenin protein fractions. Grain weight was reduced with heat stress (HS) in all RNAi lines, whereas gliadin content was increased in the wild-types. With respect to gliadin content, RNAi lines responded to HS and N availability differently from their respective wild-types, except for ω-gliadin content, indicating a very clear stability of silencing under different environmental conditions. In a context of increased temperature and HS events, and in environments with different N availability, the RNAi lines with down-regulated gliadins seem well suited for the production of wheat grain with low gliadin content.

Temperature and nitrogen (N) availability are two important environmental factors that may produce important changes in grain composition during grain filling of bread wheat. In this study, four wheat lines with the down-regulation of gliadins by means of RNA interference (RNAi) have been characterized to determine the effect of thermal stress and N availability on grain weight and quality; with focus on gliadin and glutenin protein fractions. Grain weight was reduced with heat stress (HS) in all RNAi lines, whereas gliadin content was increased in the wild-types. With respect to gliadin content, RNAi lines responded to HS and N availability differently from their respective wild-types, except for ω-gliadin content, indicating a very clear stability of silencing under different environmental conditions. In a context of increased temperature and HS events, and in environments with different N availability, the RNAi lines with down-regulated gliadins seem well suited for the production of wheat grain with low gliadin content. [ABSTRACT FROM AUTHOR]

BACKGROUND Previous research has suggested that proteins and other quality parameters of wheats may have changed over a century of wheat breeding. These changes may affect protein digestibility. The in vitro protein digestibility of breads made with 21 cultivars of wheat introduced or released in the USA between 1870 and 2013 was therefore evaluated. RESULTS: Protein digestibility increased with release year, but was not normally distributed; three older cultivars had significantly lower digestibility than the other cultivars: 42.0 ± 0.3 mol% (primary amino N/total N) versus 34.7 ± 0.7 mol%; P < 0.001. High molecular weight (MW) protein fractions increased and low MW protein fractions decreased with release year, but these changes were not related to protein digestibility. Thus, other differences in protein composition or other flour components may contribute to diminished digestibility of the three older cultivars. CONCLUSIONS: This study identified differences in protein digestibility among wheat cultivars that may have important implications for human nutrition. Further investigation is required to determine the specific characteristics that differentiate high‐ and low‐digestibility wheat cultivars. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Chemical oxidizers and redox enzymes have traditionally been used to enhance the quality of baked goods. However, consumers now seek natural and clean-label ingredients, avoiding those with chemical-sounding names. Honey, a natural source of glucose oxidase (GOX), represents a promising alternative to purified enzymes for baking purposes. This study aimed to evaluate the effect of honey on the molecular structure and microstructure of gluten proteins in sourdough fermented by different lactic acid bacteria (LAB) strains. Four wheat-rye (1:1) sourdoughs were prepared, each supplemented with honey and inoculated with a different LAB strain. Additionally, two uninoculated doughs, one with honey (honey dough) and the other without (control dough), were prepared under identical conditions. Electronic paramagnetic resonance spectroscopy revealed the presence of hydrogen peroxide in honey solutions, indicating its role as an active source of GOX. Raman spectroscopy showed that honey addition altered the molecular structure of gluten by increasing the proportion of random coils at the expense of α-helix structures. This change is likely attributed to the competition between honey sugars and gluten proteins for water molecules in this system. Moreover, honey led to a decrease in the free sulfhydryl content of gluten compared to the control dough, suggesting an increase in disulfide crosslinking points. These enhanced protein–protein interactions were observed in scanning electron microscopy micrographs as a coarse gluten network composed of interconnected strands and fibrils. All LAB strains exhibited optimal acidification (pH < 4.3) in honey-supplemented sourdoughs, promoting the hydrolysis of gluten proteins into smaller fragments. Overall, honey-supplemented sourdoughs showed a gradual increase in the β-sheet content while decreasing the proportion of random coils over time. This trend suggests that the polypeptide fragments interacted through interchain hydrogen bonds, leading to a more ordered structure, which likely contributes to providing dough with good baking aptitude. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the impact of carboxymethyl chitosan (CMCh) on rice dough quality during freeze–thaw cycles (FTCs). We conducted a comprehensive analysis of frozen rice dough using various techniques, including scanning electron microscopy (SEM), low–field nuclear magnetic resonance (LF–NMR), confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FT–IR), size–exclusion high–performance liquid chromatography (SE–HPLC), small–angle X–ray scattering (SAXS), X–ray diffraction (X–RD), differential scanning calorimetry (DSC), and rapid visco–analysis (RVA). Our results revealed that adding carboxymethyl chitosan (CMCh) to frozen rice dough reduced damage to starch granules and gluten proteins during FTCs compared to dough without CMCh. This resulted in the deceleration of the modification of the ordered protein structure. Furthermore, the inclusion of CMCh resulted in increased cross–linking with the large protein polymer, impairing the capacity of bound water to transition into free water within the frozen rice dough. Consequently, this led to an elevation in the storage modulus (G′), effectively retarding the textural transformation of the frozen rice dough. Introducing CMCh to frozen rice dough subsequently decelerated the alterations in the short-range order and crystal structures of starch, consequently modifying the pasting and thermal properties of the frozen rice dough. Based on the results obtained from our experiments, CMCh has a decelerating effect on the impact of frozen rice dough on FTCs. [Display omitted] • A new approach to improve on the quality of frozen rice dough was constructed. • Ice crystals destroyed the integrity of gluten and starch during freeze thaw cycles. • Carboxymethyl chitosan inhibited water migration of dough during freeze thaw cycles. • Carboxymethyl chitosan improved the rheological of dough during freeze thaw cycles. • Carboxymethyl chitosan interacted with gluten to prevent depolymerization. [ABSTRACT FROM AUTHOR]

Durum wheat is a staple crop for the Mediterranean diet because of its adaptability to environmental pressure and for its large use in cereal-based food products, such as pasta and bread, as a source of calories and proteins. Durum wheat whole grains are also highly valued for their peculiar amount of dietary fiber and minerals, as well as bioactive compounds of particular interest for their putative health-beneficial properties, including polyphenols, carotenoids, tocopherols, tocotrienols, and phytosterols. In Mediterranean environments, durum wheat is mostly grown under rainfed conditions, where the crop often experiences environmental stresses, especially water deficit and soil salinity that may induce a hyperosmotic stress. In particular, changes in C and N accumulation due to these abiotic conditions, during grain filling, can influence starch and storage protein amount and composition in durum wheat caryopsis, thus influencing yield and quality traits. Recent advancements regarding the influence of water deficit and salinity stress on durum wheat are critically discussed. In particular, a focus on stress-induced changes in (a) grain protein content and composition in relation to technological and health quality; (b) starch and dietary fiber accumulation and composition; (c) phytochemical composition; (d) health-related grain micronutrient accumulation, such as Fe and Zn.

Late-season N application through foliar spraying is recognized as an efficient agronomic practice for improving grain quality in common wheat, although the major part of N is still supplied by soil fertilization. This study assessed the impact of various N doses entirely applied by repeated foliar sprayings on wheat growth, yield and quality, in comparison with conventional soil fertilization management with a recommended dose of 160 kg N ha−1 as ammonium nitrate (C-M). Doses of 96, 104 and 120 kg N ha−1 as both UAN (urea-ammonium-nitrate) and urea applied by foliar spraying were evaluated in a 2-year field trial in Northern Italy in a silty loam soil with 1.7% organic matter. Here, it was demonstrated that the canopy greenness was similar in all treatments, with slight grain yield increases by the lowest foliar N dose vs. C-M. The higher N foliar doses mainly improved the grain protein content and both high- and low-molecular-weight glutenin subunits (HMW-GS, LMW-GS), particularly with urea. It is concluded that in our fertile soil, managing N fertilization exclusively through foliar spraying is feasible without compromising grain yield and ameliorating quality at the same time. Improved nutrient use efficiency and beneficial environmental effects are also expected by reducing the nitrogen load on the agricultural fields by 25–40%.

Raman spectroscopy is a useful method in biological, biomedical, food, and agricultural studies, allowing the simultaneous examination of various chemical compounds and evaluation of molecular changes occurring in tested objects. The purpose of our research was to explain how the elimination of ω-fractions from the wheat gliadin complex influences the secondary structures of the remaining αβγ-gliadins. To this aim, we analyzed the endosperm of wheat kernels as well as gliadin proteins extracted from two winter wheat genotypes: wasko.gl+ (control genotype containing the full set of gliadins) and wasko.gl− (modified genotype lacking all ω-gliadins). Based on the decomposition of the amide I band, we observed a moderate increase in β-forms (sheets and turns) at the expense of α-helical and random coil structures for gliadins isolated from the flour of the wasko.gl− line. Since ω-gliadins contain no cysteine residues, they do not participate in the formation of the disulfide bridges that stabilize the protein structure. However, they can interact with other proteins via weak, low-energetic hydrogen bonds. We conclude that the elimination of ω-fractions from the gliadin complex causes minor modifications in secondary structures of the remaining gliadin proteins. In our opinion, these small, structural changes of proteins may lead to alterations in gliadin allergenicity.

The alpha gliadins are a group of more than 20 proteins with very similar sequences that comprise about 15%–20% of the total flour protein and contribute to the functional properties of wheat flour dough. Some alpha gliadins also contain immunodominant epitopes that trigger celiac disease, a chronic autoimmune disease that affects approximately 1% of the worldwide population. In an attempt to reduce the immunogenic potential of wheat flour from the U.S. spring wheat cultivar Butte 86, RNA interference was used to silence a subset of alpha gliadin genes encoding proteins containing celiac disease epitopes. Two of the resulting transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis combined with tandem mass spectrometry. Although the RNA interference construct was designed to target only some alpha gliadin genes, all alpha gliadins were effectively silenced in the transgenic plants. In addition, some off-target silencing of high molecular weight glutenin subunits was detected in both transgenic lines. Compensatory effects were not observed within other gluten protein classes. Reactivities of IgG and IgA antibodies from a cohort of patients with celiac disease toward proteins from the transgenic lines were reduced significantly relative to the nontransgenic line. Both mixing properties and SDS sedimentation volumes suggested a decrease in dough strength in the transgenic lines when compared to the control. The data suggest that it will be difficult to selectively silence specific genes within families as complex as the wheat alpha gliadins. Nonetheless, it may be possible to reduce the immunogenic potential of the flour and still retain many of the functional properties essential for the utilization of wheat.

The omega-1,2 gliadins are a group of wheat gluten proteins that contain immunodominant epitopes for celiac disease (CD) and also have been associated with food allergies. To reduce the levels of these proteins in the flour, bread wheat (Triticum aestivum cv. Butte 86) was genetically transformed with an RNA interference plasmid that targeted a 141 bp region at the 5′ end of an omega-1,2 gliadin gene. Flour proteins from two transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis and tandem mass spectrometry. In one line, the omega-1,2 gliadins were missing with few other changes in the proteome. In the other line, striking changes in the proteome were observed and nearly all gliadins and low molecular weight glutenin subunits (LMW-GS) were absent. High molecular weight glutenin subunits (HMW-GS) increased in this line and those that showed the largest increases had molecular weights slightly less than those in the non-transgenic, possibly due to post-translational processing. In addition, there were increases in non-gluten proteins such as triticins, purinins, globulins, serpins, and alpha-amylase/protease inhibitors. Reactivity of flour proteins with serum IgG and IgA antibodies from a cohort of CD patients was reduced significantly in both transgenic lines. Both mixing time and tolerance were improved in the line without omega-1,2 gliadins while mixing properties were diminished in the line missing most gluten proteins. The data suggest that biotechnology approaches may be used to create wheat lines with reduced immunogenic potential in the context of gluten sensitivity without compromising end-use quality.

The alpha gliadins are a group of more than 20 proteins with very similar sequences that comprise about 15%–20% of the total flour protein and contribute to the functional properties of wheat flour dough. Some alpha gliadins also contain immunodominant epitopes that trigger celiac disease, a chronic autoimmune disease that affects approximately 1% of the worldwide population. In an attempt to reduce the immunogenic potential of wheat flour from the U.S. spring wheat cultivar Butte 86, RNA interference was used to silence a subset of alpha gliadin genes encoding proteins containing celiac disease epitopes. Two of the resulting transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis combined with tandem mass spectrometry. Although the RNA interference construct was designed to target only some alpha gliadin genes, all alpha gliadins were effectively silenced in the transgenic plants. In addition, some off-target silencing of high molecular weight glutenin subunits was detected in both transgenic lines. Compensatory effects were not observed within other gluten protein classes. Reactivities of IgG and IgA antibodies from a cohort of patients with celiac disease toward proteins from the transgenic lines were reduced significantly relative to the nontransgenic line. Both mixing properties and SDS sedimentation volumes suggested a decrease in dough strength in the transgenic lines when compared to the control. The data suggest that it will be difficult to selectively silence specific genes within families as complex as the wheat alpha gliadins. Nonetheless, it may be possible to reduce the immunogenic potential of the flour and still retain many of the functional properties essential for the utilization of wheat. [ABSTRACT FROM AUTHOR]

Although the economic value of wheat flour is determined by the complement of gluten proteins, these proteins have been challenging to study because of the complexity of the major protein groups and the tremendous sequence diversity among wheat cultivars. The completion of a high-quality wheat genome sequence from the reference wheat Chinese Spring recently facilitated the assembly and annotation of a complete set of gluten protein genes from a single cultivar, making it possible to link individual proteins in the flour to specific gene sequences. In a proteomic analysis of total wheat flour protein from Chinese Spring using quantitative two-dimensional gel electrophoresis combined with tandem mass spectrometry, gliadins or low-molecular-weight glutenin subunits were identified as the predominant proteins in 72 protein spots. Individual spots were associated with 40 of 56 Chinese Spring gene sequences, including 16 of 26 alpha gliadins, 10 of 11 gamma gliadins, six of seven omega gliadins, one of two delta gliadins, and nine of ten LMW-GS. Most genes that were not associated with protein spots were either expressed at low levels in endosperm or encoded proteins with high similarity to other proteins. A wide range of protein accumulation levels were observed and discrepancies between transcript levels and protein levels were noted. This work together with similar studies using other commercial cultivars should provide new insight into the molecular basis of wheat flour quality and allergenic potential. [ABSTRACT FROM AUTHOR]

Wheat gluten proteins are decisive for the industrial properties of flour, so alterations resulting from grain infection with Fusarium graminearum produce changes in the glutenin content that affect the baking properties. This work analyzes the high-molecular-weight glutenin changes from wheat flour with different degrees of F. graminearum infection at field, since these proteins are determinant for the quality properties of flour. Wheat cultivars—on field trials—infected with F. graminearum isolates of diverse aggressiveness showed severity values between 9.1 and 42.58% and thousand kernel weight values between 28.12 and 32.33 g. Negative correlations between severity and protein content and positive correlations between yield and protein content were observed, employing reversed-phase high-performance liquid chromatography and polyacrylamide gel electrophoresis. Furthermore, the protein signal changes were in agreement for both methodological approaches. Also, the degree of disease observed and the protein changes on infected wheat cultivars varied in relation with the aggressiveness of the isolate responsible for the infection. The principal component analysis showed a close arrangement among protein values obtained by HPLC. For each cultivar, two principal components were obtained, which explained 80.85%, 88.48%, and 93.33% of the total variance (cultivars Sy200, AGP Fast, and Klein Tigre respectively). To our knowledge, the approaches employed for the analysis of protein changes according to the degree of disease, as well as the thorough statistical analysis, are novel for the study of Fusarium Head Blight. [ABSTRACT FROM AUTHOR]

The omega-1,2 gliadins are a group of wheat gluten proteins that contain immunodominant epitopes for celiac disease (CD) and also have been associated with food allergies. To reduce the levels of these proteins in the flour, bread wheat (Triticum aestivum cv. Butte 86) was genetically transformed with an RNA interference plasmid that targeted a 141 bp region at the 5′ end of an omega-1,2 gliadin gene. Flour proteins from two transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis and tandem mass spectrometry. In one line, the omega-1,2 gliadins were missing with few other changes in the proteome. In the other line, striking changes in the proteome were observed and nearly all gliadins and low molecular weight glutenin subunits (LMW-GS) were absent. High molecular weight glutenin subunits (HMW-GS) increased in this line and those that showed the largest increases had molecular weights slightly less than those in the non-transgenic, possibly due to post-translational processing. In addition, there were increases in non-gluten proteins such as triticins, purinins, globulins, serpins, and alpha-amylase/protease inhibitors. Reactivity of flour proteins with serum IgG and IgA antibodies from a cohort of CD patients was reduced significantly in both transgenic lines. Both mixing time and tolerance were improved in the line without omega-1,2 gliadins while mixing properties were diminished in the line missing most gluten proteins. The data suggest that biotechnology approaches may be used to create wheat lines with reduced immunogenic potential in the context of gluten sensitivity without compromising end-use quality. [ABSTRACT FROM AUTHOR]

The possible interaction of six hydrocolloids with gluten proteins and starch has been investigated. It has been found that λ-carrageenan, high methoxyl orange pectin, guar gum and konjac glucomannan could form complexes with gluten proteins and induce more disordered but less crosslinked protein structures through electrostatic interactions and hydrogen bonding. In general, the effect of hydrocolloid on gluten is due to both interaction and incompatibility between hydrocolloids and gluten proteins. The results of dough microstructure also confirmed this statement. These four hydrocolloids also have strong hydrogen bonding capacity with starch, and show remarkable effect on starch gelatinization and retrogradation. The hydrogen bonding between hydrocolloids and starch also play a key role on starch thermal properties besides the physicochemical properties of hydrocolloids. • Hydrocolloids action on gluten is due to their interaction and incompatibility. • The linear hydrocolloids were more likely to interact with gluten proteins. • Too strong hydrocolloids-gluten interaction caused instability of gluten network. • Hydrocolloids-starch hydrogen bonding play a key role on starch thermal properties. [ABSTRACT FROM AUTHOR]

Changes in the microstructure and secondary structure of sourdough gluten proteins were studied. Four strains of lactic acid bacteria (LAB) were used in fermentations, Lactobacillus delbrueckii subsp. bulgaricus (LB), Lactobacillus fermentum (LF), Lactobacillus plantarum (LP), and Pediococcus pentosaceus (PP). LAB fermentative profiles were performed by potenciometric measurements, microstructural analyses by scanning electron microscopy (SEM), and conformational changes by Raman spectroscopy. Gluten proteins experienced different degree of depolymerisation into defined microstructures, as fibril networks and laminar-like structures, and their occurrence was associated to an increase in β-sheets structures. These changes were dependent upon the distinctive acidifying kinetics of each strain. Gluten proteins of LF and LP sourdough were preferably arranged into laminar structures, and, in both cases, parallel β-sheet was the predominant conformation. Meanwhile for LB and PP sourdough, the development of three-dimensional fibril networks prevailed and it was accompanied by an increase of antiparallel β-sheets. LAB fermentative activity also lead to modifications in disulphide bonds and in the microenvironment concerning aromatic amino acids. • Lactic acid bacteria induced changes in secondary structure of gluten proteins. • Each lactic acid bacteria produced a distinctive change in protein structure. • Gluten macropolymer was depolymerised into fibril- and laminar-like microstructures. • The development of fibril networks was associated to antiparallel β-sheets. • Laminar-like microstructure was related to parallel β-sheets. [ABSTRACT FROM AUTHOR]

Highlights • Post anthesis heat stress had more profound effects than elevated CO 2 on protein quality. • Contents of grain proteins decreased due to elevated CO 2 but increased by heat stress. • Elevated CO 2 decreased glutenin macropolyers (GMP) content and large GMP fraction. • Combination of elevated CO 2 and heat stress decreased the contents of storage proteins. • Co-occurring elevated CO 2 and heat stress did not affect GMP and amino acid content. Abstract Spring wheat plants were grown under two CO 2 concentrations (380 and 550 μmol mol−1) and two temperature treatments (ambient and post-anthesis heat stress) to investigate the effects of elevated CO 2 and heat stress on grain protein quality. Contents of protein components, glutenin macropolymers (GMP) and amino acids in grains decreased due to elevated CO 2 , while increased by high temperature. The combination of elevated CO 2 and heat stress increased the contents of total protein and albumin, but decreased the contents of gliadin and glutenin, while the content and particle size distribution of GMP as well as the contents of amino acids were not significantly affected. Furthermore, we found that the content and particle size distribution of GMP were not only determined by the contents of proteins and high-molecular-weight glutenin subunits, but also related to the contents of amino acids containing disulfide bonds, which favor the formation of large insoluble polymers. [ABSTRACT FROM AUTHOR]

Highlights • The iTRAQ identified 591 proteins into 17 categories in mature grain flour. • N topdressing timing regulated expressions of 97 proteins in 11 biological processes. • Gliadins and HMW-GS were more sensitive to N topdressed timing than LMW-GS. • Delaying topdressed N altered grain hardness and flour allergic protein content. • Change of N topdressing timing from jointing stage caused grain yield loss. Abstract Nitrogen fertilization regimes significantly affect both grain quality and yield. Wheat plants were subjected to different application timing of topdressed nitrogen at the emergence of the top fifth (TL5), top third (TL3) and top first leaf (TL1), respectively. The iTRAQ (isobaric tag for relative and absolute quantitation) technology was adopted to obtain the complete proteome of wheat flour and to identify the differentially expressed proteins (DEPs) as regulated by nitrogen topdressing timing. Collectively, 591 proteins into 17 functional categories in flour of mature grains were identified. In comparison to TL3, 50 and 63 DEPs were identified in TL5 and TL1, respectively. Nine of the DEPs commonly dependent on nitrogen topdressing timing are the γ-gliadins or high-molecular-weight glutenin subunits. Additionally, delaying nitrogen topdressing modified the grain hardness and allergic protein content. The results suggested that altering nitrogen topdressing timing is a potential strategy for pursuing targeted processing quality of wheat flour. [ABSTRACT FROM AUTHOR]

One of the main concerns in gluten analysis is to achieve efficient extraction of gluten proteins. Conventional ethanol-based extraction solutions are inefficient and, because of this, it is necessary to use reducing agents or acids for proper solubilization. The extraction recommended by CODEX Standard 118-1979 (revised 2008) utilizes Cocktail solution (patent WO 02/092633 A1). However, it is harmful with a disgusting odor and is not compatible with some immunological techniques. Here, the versatility and extraction capacity of a new Universal Gluten Extraction Solution (UGES) (patent ES 2 392 412 A1) were evaluated using different methodological conditions, food matrices, and various immunological methods. UGES includes safer compounds for both the user and the environment, and it displayed similar extraction efficiency to that of the extraction method recommended for sandwich enzyme-linked immunosorbent assay (ELISA). The extraction time was significantly reduced from 100 to 40 min, depending on the type of the sample. Furthermore, unlike the currently used solution, UGES is compatible with competitive ELISA.

Understanding the interplay between gluten and wheat starch is crucial for elucidating the digestibility mechanism of gluten in wheat-based products. However, this mechanism remains under-investigated. This study sought to elucidate the influence of starch-induced protein structural modifications on gluten digestion. Our findings revealed that starch considerably enhanced gluten digestion. In the presence of starch, gluten protein digestibility increased from 10.91 % (in the control group with a gluten-to-starch ratio of 1:0) to 14.40 % (in the complex with a gluten-to-corn starch ratio of 1:1). The diminished gluten protein digestibility due to starch may be ascribed to modifications in protein configuration and aggregation behavior. Morphological studies suggested that starch not only functioned as filler particles but also diluted the gluten matrix. A protein network assessment further affirmed that both the junction density and branching rate of gluten proteins decreased notably by 29.9 % and 25.1 %, respectively. Conversely, lacunarity increased by 1.92-fold, compromising the cohesiveness and connectivity of the gluten matrix. Elevated starch concentrations suppressed the formation of disulfide bonds, impeding gluten protein aggregation. Concurrently, gluten-starch interactions were governed by hydrogen bonds and hydrophobic associations. In summary, starch augmented gluten protein digestibility by curtailing their polymerization. This revelation might offer novel perspectives on optimizing gluten protein digestion and utilization. [Display omitted] • Starch facilitated gluten digestion by inhibiting its aggregation. • Starch changed the rheological and thermal properties of gluten proteins. • The network structure of gluten was weakened by starch. • Starch interfered with the formation of disulfide bonded gluten aggregates. [ABSTRACT FROM AUTHOR]