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Fertilisation of cereal crops with nitrogen (N) has increased in the last five decades. In particular, the fertilisation of wheat crops increased by nearly one order of magnitude from 1961 to 2010, from 9.84 to 93.8 kg N ha−1 y−1. We hypothesized that this intensification of N fertilisation would increase the content of allergenic proteins in wheat which could likely be associated with the increased pathology of coeliac disease in human populations. An increase in the per capita intake of gliadin proteins, the group of gluten proteins principally responsible for the development of coeliac disease, would be the responsible factor. We conducted a global meta-analysis of available reports that supported our hypothesis: wheat plants growing in soils receiving higher doses of N fertilizer have higher total gluten, total gliadin, α/β-gliadin, γ-gliadin and ω-gliadin contents and higher gliadin transcription in their grain. We thereafter calculated the per capita annual average intake of gliadins from wheat and derived foods and found that it increased from 1961 to 2010 from approximately 2.4 to 3.8 kg y−1 per capita (+1.4 ± 0.18 kg y−1 per capita, mean ± SE), i.e., increased by 58 ± 7.5%. Finally, we found that this increase was positively correlated with the increase in the rates of coeliac disease in all the available studies with temporal series of coeliac disease. The impacts and damage of over-fertilisation have been observed at an environmental scale (e.g., eutrophication and acid rain), but a potential direct effect of over-fertilisation is thus also possible on human health (coeliac disease).

Health benefitting potential of twenty leading wheat varieties was assessed for grain nutritional quality status in relation to antigenic reactivity level of gluten protein fractions. Among the nutritional parameters, macronutrients viz. starch, total sugar, total protein and gluten content were observed maximum in the varieties RAJ4120, RAJ4083, RAJ3077, and WH1021 respectively. Micronutrients- zinc and iron and phytochemicals- total phenolics and flavonoids were observed to be maximum in RAJ4083. Among the four protein fraction, albumin and globulin contents were the highest in RAJ3077, whereas gliadin and gluten content was maximum in GW322 and minimum in RAJ4120. The varieties were also characterized by SDS-PAGE and the results revealed significant polymorphism in all of the four protein fractions. The antigenic properties of flour gliadin proteins as evaluated by ELISA revealed that all the varieties possessed antigenicity with highest level in GW322 (0.217 OD). However, all the varieties possessed good baking qualities as studied by rheological measurements. [ABSTRACT FROM AUTHOR]

FTIR spectroscopy was used to determine changes in secondary structure, as well as water state, in gluten and model doughs supplemented by four fibre polysaccharides (microcrystalline cellulose, inulin, apple pectin and citrus pectin). The gluten and model doughs were obtained from commercially available wheat gluten and model flour, respectively. The polysaccharides were used in five concentrations: 3%, 6%, 9%, 12% and 18%. Analysis of the FTIR spectra indicated that polysaccharides could be divided into two groups: first – microcrystalline cellulose and inulin, second – apple and citrus pectins that induced opposite structural changes. Changes in secondary structure concern mainly β-sheets and β-turns that form aggregated β-structures, suggesting dehydration of the gluten matrix as a result of competition for water between gluten proteins and polysaccharides. Moreover, the positive band at ca. 1226 cm −1 in the spectra of pectin-modified samples indicates formation of ‘ether’ type hydrogen bonds between gluten proteins and pectins. [ABSTRACT FROM AUTHOR]

Background and objectives: Thirty hard red spring wheat cultivars released between 1910 and 2013 were studied to determine the changes in quality characteristics that occurred over time, and to determine their association with protein composition. Findings: Significant positive correlations (p ⩽ .01) were found between release year and dough quality characteristics, such as farinograph peak time and stability. In sizeexclusion HPLC analysis of proteins, significant positive correlations (p ⩽ .01) were observed between release year, glutenin polymeric proteins, and the x-gliadin fraction, which also showed significant positive correlations (p ⩽ .01) with dough properties. In reverse-phase HPLC analysis of gliadins, five x-gliadin peaks showed significant correlations (p ⩽ .05) with year and farinograph characteristics. Mass spectrometry was performed to identify the proteins in these peaks. Conclusions: Overall, the results indicated that breeding efforts improved dough properties, which could be associated with quantitative variations in glutenin polymeric proteins and certain subfractions of x-gliadins. Significance and novelty: Glutenin polymeric proteins, together with specific x-gliadin proteins, may play an important role in baking quality of spring wheat. [ABSTRACT FROM AUTHOR]

Data on protein fractions proportion obtained with RP-HPLC and technological quality parameters for 29 wheat cultivars grown in Serbia and Croatia were used for studying of interrelations among wheat protein fractions with different solubility and molecular weight properties by multivariate (PCA) analysis. Obtained trends were used as the base for investigations related to differentiation of technological quality among wheat cultivars with different combination of protein fractions compositions using univariate statistics (ANOVA followed by Duncan’s test) in order to draw out information about interrelations between protein fractions proportion in wheat cultivars and their technological quality. Analysis based on first four PCA factors (89.04% of variability) pointed out at interdependences between: (1) high content of albumins and globulins, low gliadins content and gliadins/glutenins ratio, high ω-gliadins, LMW glutenins and low α- gliadins share in total protein with low water absorption, high energy and high resistance to extensibility ratio, (2) high albumin and globulin content and high proportion of ω-gliadins in total protein and low extensigraph extensibility, (3) high share of high molecular weight glutenins (HMW-GS) in total proteins, high extensigraph resistance/extensibility ratio and (4) high γ-gliadins share in total protein and low extensigraph resistance/extensibility ratio. [Projekat Ministarstva nauke Republike Srbije, br. TR 31007]

Structural changes of proteins in fresh noodles during mixing, resting, sheeting, and cooking were investigated. The protein structural changes were evaluated by measuring the protein content, molecular weight, thiol and disulfide contents, secondary structure, thermal properties, microstructure, and mean particle size. The protein content was not significantly changed during fresh noodle processing. The wheat protein molecular weight decreased from 66.2 to 22.0 kDa during the cooking process. The disulfide content increased during the mixing and cooking processes. Additionally, the cooking process caused an increase in the number of gluten protein absorption peaks in the FTIR analysis. The secondary structure was mainly composed of β-sheets, and their proportion decreased in the cooking process. Gluten proteins were demonstrated to have high thermal stability with an average denaturation temperature of 84.9°C. There was a significant relationship between the gluten protein properties and fresh noodle processing. [ABSTRACT FROM AUTHOR]

FT-Raman spectroscopy, thermogravimetry and differential scanning calorimetry were used to study changes in structure of gluten proteins and their thermal properties influenced by four dietary fibre polysaccharides (microcrystalline cellulose, inulin, apple pectin and citrus pectin) during development of a model dough. The flour reconstituted from wheat starch and wheat gluten was mixed with the polysaccharides in five concentrations: 3%, 6%, 9%, 12% and 18%. The obtained results showed that all polysaccharides induced similar changes in secondary structure of gluten proteins concerning formation of aggregates (1604 cm −1 ), H-bonded parallel- and antiparallel-β-sheets (1690 cm −1 ) and H-bonded β-turns (1664 cm −1 ). These changes concerned mainly glutenins since β-structures are characteristic for them. The observed structural changes confirmed hypothesis about partial dehydration of gluten network after polysaccharides addition. The gluten aggregation and dehydration processes were also reflected in the DSC results, while the TGA ones showed that gluten network remained thermally stable after polysaccharides addition. [ABSTRACT FROM AUTHOR]

Gluten proteins are major determinants of the bread making quality of wheat, but also of important wheat-related disorders, including coeliac disease (CD), and allergies. We carried out a proteomic study using the total grain proteins from two low-gliadin wheat lines, obtained by RNAi, and the untransformed wild type as reference. The impact of silencing on both target and on non-target proteins was evaluated. Because of the great protein complexity, we performed separate analyses of four kernel protein fractions: gliadins and glutenin subunits, and metabolic and CM-like proteins, by using a classical 2D electrophoresis gel based approach followed by RP-HPLC/nESI-MS/MS. As a result of the strong down-regulation of gliadins, the HMW-GS, metabolic and chloroform/methanol soluble proteins were over-accumulated in the transgenic lines, especially in the line D793, which showed the highest silencing of gliadins. Basing on these data, and considering that metabolic proteins and chloroform/methanol soluble proteins (CM-like), such as the α-amylase/trypsin inhibitor family, β-amylase and serpins, were related to wheat allergens, further in vivo analysis will be needed, especially those related to clinical trials in controlled patients, to determine if these lines could be used for food preparation for celiac or other gluten intolerant groups. Biological significance Several enteropathies and allergies are related to wheat proteins. Biotechnological techniques such as genetic transformation and RNA interference have allowed the silencing of gliadin genes, providing lines with very low gliadin content in the grains. We report a proteomic-based approach to characterize two low-gliadin transgenic wheat lines obtained by RNAi technology. These lines harbor the same silencing fragment, but driven by two different endosperm specific promoters (γ-gliadin and D-hordein). The comprehensive proteome analysis of these transgenic lines, by combining two-dimensional electrophoresis and RP-HPLC/nESI-MS/MS, provided a large number of spots differentially expressed between the control and the transgenic lines. Hence, the results of this study will facilitate further safety evaluation of these transgenic lines. [ABSTRACT FROM AUTHOR]

The effect of four dietary fibre polysaccharides (microcrystalline cellulose (MCC), inulin (IN), apple pectin (AP) and citrus pectin (CP)) on structure and thermal properties of gluten proteins in the gluten dough was studied with application of FT-Raman spectroscopy, thermogravimetry (TGA) and differential scanning calorimetry (DSC). The commercially available wheat gluten was mixed with the polysaccharides in five concentrations: 3%, 6%, 9%, 12% and 18%. The obtained results showed that MCC, IN and small amount of pectin (3% and 6%) induced similar changes in the secondary structure of gluten proteins concerning formation of antiparallel-β-sheets connected by intermolecular hydrogen bonds from α-helices and β-sheets. Higher contents of pectin (9–18%) led to formation of aggregates and β-like aggregates. The observed changes in the secondary structure, conformation of disulphide bridges and environment of tyrosine and tryptophan of gluten proteins indicated partial dehydration of gluten network as a result of a competitive water binding by polysaccharides molecules (especially MCC and IN) during the dough mixing. TGA results also confirmed this statement. However, slightly different results were obtained for pectins. They not only competed for water with gluten proteins but also interacted with them since a thermogravimetric peak characteristic for pectin was observed in the derivative TGA profiles of gluten – pectin mixtures. [ABSTRACT FROM AUTHOR]

We adopted an approach based on peptide immobilized pH gradient-isoelectric focusing (IPG-IEF) separation, coupled with LC-MS/MS, in order to maximize coverage of the beer proteome. A lager beer brewed using traditional Czech technology was degassed, desalted and digested. Tryptic peptides were separated by isoelectric focusing on an immobilized pH gradient strip and, after separation, the gel strip was divided into seven equally sized parts. Peptides extracted from gel fractions were analyzed by LC-MS/MS. This approach resulted in a three-fold increase in the number of proteins identified (over 1700) when compared to analysis of unfractionated beer processed by a filter-aided sample preparation (FASP). Over 1900 protein groups (PGs) in total were identified by both approaches. Significance The study significantly extends knowledge about the beer proteome and demonstrates its complexity. Detailed knowledge of the protein content, especially gluten proteins, will enhance the evaluation of potential health risks related to beer consumption (coeliac disease) and will contribute to improving beer quality. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare efficiency of RP-HPLC (Reversed-Phase High-Performance Liquid Chromatography) and LOC (Lab-on-Chip) methods for wheat gluten protein quantification regarding clustering of wheat cultivars according to the genetic similarity (HMW-GS combinations), as well as to explore relations of these two methods to wheat quality parameters. For that purpose, wheat quality parameters (protein content, falling number, wet gluten content, gluten index, Farinograph, Extensograph, and Amylograph), as well as amounts of gliadin and glutenin fractions by RP-HPLC and LOC methods were determined in two different sets of wheat cultivars (Croatian and Serbian). The percentages of gluten proteins and the values of quality parameters were used to characterize the samples by principal component analysis (PCA). Gluten protein quantification performed by method based on the protein fraction separation by molecular weights (LOC) was better for grouping of genetically similar wheat cultivars than quantification of proteins separated by their different solubility in specified solvent gradient (RP-HPLC). LOC method showed higher potential in wheat quality prediction. [ABSTRACT FROM AUTHOR]

The use of vital wheat gluten in the baking industry and wheat flour mills aims to improve the rheological characteristics of flour considered unsuitable to obtain products such as sliced bread, French bread, high-fiber breads, and other products that require strong flours. To improve characteristics such as flour strength, dough mixing tolerance, and bread volume, vital wheat gluten is added to flour at levels that can vary from 2% to 10% (flour basis), with 5% being a commonly used dosage. However, the vital wheat gluten commercialized in the market has few quality specifications, especially related to the characteristics of the proteins that constitute it and are responsible for the formation of the viscoelastic gluten network. Information on protein quality is important, because variations are observed in the technological quality of vital wheat gluten obtained from different sources, which could be associated to damage caused to proteins during the obtainment process. Several tests, either physical-chemical analyses, or rheological tests, are carried out to establish gluten quality; however, they are sometimes time-consuming and costly. Although these tests give good answers to specify gluten quality, flour mills, and the baking industries require fast and simple tests to evaluate the uses and/or dosage of vital gluten addition to wheat flour. This review covers the concepts, uses, obtainment processes, and quality analysis of vital wheat gluten, as well as simple tests to help identify details about protein quality of commercial vital wheat gluten. [ABSTRACT FROM AUTHOR]

Nowadays, consumers demand dietary fibre-enriched products of appropriate taste, texture, smell and appearance. Unfortunately, addition of the dietary fibre supplements to bread significantly reduces its quality which is connected with changes in the structure of gluten proteins. Structural changes as well as changes in the water state of gluten matrix induced by eight dietary fibres were observed by using Fourier transform infrared spectroscopy. To facilitate this the difference spectra were calculated by subtraction of the control (gluten only) infrared spectrum from the spectra of gluten-fibre mixtures. The presence of positive bands at ca. 1597 and 1235 cm −1 indicated aggregation of gluten proteins into hydrogen bonded β-sheets. These β-sheets can be formed by other β-sheets, antiparallel-β-sheets, β-turns and/or α-helices. The aggregation is probably induced by partial dehydration of gluten matrix due to competition for water molecules between gluten proteins and fibre polysaccharides. This assumption is confirmed by the presence of the negative band at 3237 cm −1 and decrease in the intensity of the band at 3051 cm −1 . These bands are assigned to the weak and strong H-bonds in the gluten matrix, respectively. The results indicated that both weak and strong H-bonds are necessary to dough formation of adequate rheological properties. [ABSTRACT FROM AUTHOR]

The fermentation capacity of frozen dough determines its handling properties and the quality of final product. In this study, the effects of sanxan on the fermentation capacity of frozen dough during freeze-thawed cycles (FTCs) were investigated. The results showed that 0.5% sanxan improved the fermentation capacity of frozen dough during FTCs. An increase in yeast survival rate indicated that frozen dough with 0.5% sanxan (sanxan-dough) inhibited the death of yeast and improved the gas-production ability of yeast. After 8FTCs, compared with control-dough, the disulfide bond content of sanxan-dough significantly increased, the stability of secondary structure was enhanced, the continuity and strength of gluten network were improved; these results indicated that 0.5% sanxan enhanced the gas-holding ability of frozen dough. This study explored a new horizon for the fermentation capacity' improvement of frozen dough by sanxan in term of yeast and gluten proteins. • Sanxan improved the fermentation capacity of frozen dough. • Sanxan alleviated the death of yeast cells in frozen dough. • Sanxan heightened the strength, connectivity and uniformity of gluten network. • Sanxan improved the gas-production and holding ability of frozen dough. [ABSTRACT FROM AUTHOR]

Factor analysis and multivariate chemometric modelling for rapid assessment of baking quality of wheat cultivars from Slavonia region, Croatia, have been applied. The cultivars Žitarka, Kata, Monika, Ana, Demetra, Divana and Sana were grown under controlled conditions at the experimental field of Agricultural Institute Osijek during three years (2000–2002). Their quality properties were evaluated by 45 different chemical, physical and biochemical variables. The measured variables were grouped as: indirect quality parameters (6), farinographic parameters (7), extensographic parameters (5), baking test parameters (2) and reversed phase-high performance liquid chromatography (RP-HPLC) of gluten proteins (25). The aim of this study is to establish minimal number (three), i.e. principal factors, among the 45 variables and to derive multivariate linear regression models for their use in simple and fast prediction of wheat properties. Selection of the principal factors based on the principal component analysis (PCA) has been applied. The first three main factors of the analysis include: total glutenins (TGT), total ω-gliadins (Tω-) and the ratio of dough resistance/extensibility (R/Ext). These factors account for 76.45 % of the total variance. Linear regression models gave average regression coefficients (R) evaluated for the parameter groups: indirect quality R=0.91, baking test R=0.63, farinographic R=0.78, extensographic R=0.95 and RP-HPLC of gluten data R=0.90. Errors in the model predictions were evaluated by the 95 % significance intervals of the calibration lines. Practical applications of the models for rapid quality assessment and laboratory experiment planning were emphasized.

• Conventional, waxy and high amylose wheat lines were compared. • The protein and thiol patterns in the three wheat lines are almost identical. • Altered amylose/amylopectin ratio leads to differences in gluten development. • Starch/proteins competition for water impairs protein hydration. • Low hydration of proteins affects gluten formation in waxy and high amylose wheat. Waxy (WX) and high-amylose (HA) wheat flours have interesting functional and/or nutritional characteristics, but low technological properties compared to regular wheat. Here a set of three wheat lines, having different amylose content but sharing the same varietal background, were compared to shed light on the role of the amylose/amylopectin ratio on the protein conformational changes that lead to gluten formation. Despite the absence of differences in their protein profile, as also confirmed by thiolomic approaches, both WX and HA lines developed a weaker gluten than the control sample. The altered amylose/amylopectin ratio exerts a matrix effect establishing a competition for water with proteins, leading to a different protein structure and three-dimensional organization of the gluten network. These results add a piece to the understanding of the molecular aspects that oversee matrix effects on gluten formation in wheat, which description can be helpful for a rational optimization of the transformation process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Xyn and Gox were untilized to enhance the technofunctionality of germinated wheat. • Developed continuous gluten network by Xyn and Gox enhanced dough viscoelasticity. • The Mw of arabinoxylan was more uniform upon bread making process with Xyn and Gox. • Heat-evoked polymerization of α/γ-gliadin and glutenin was suppressed by Xyn and Gox. • High Mw glycoprotein in liquid lamella of dough enhanced thermal stability of foams. To enhance the technofunctionality of germinated wheat enriched with γ-aminobutyric acid, xylanase (Xyn) and glucose oxidase (Gox) were incorporated with emphasis on modifying the key components. Combination of Xyn and Gox enhanced steamed bread quality with optimum loaf volume and textural property. Continuous and dense gluten network was facilitated and improved viscoelasticity of dough. Water solubility of arabinoxylan (AX) enhanced with Xyn and the molecular weight was more homogeneous distributed throughout bread making process with Xyn and Gox. Polymerization behavior of α-/γ-gliadin and glutenin was suppressed in steamed bread, while incorporation of AX to insoluble proteins was enhanced by enzymes. In addition, the promoted formation of high molecular weight glycoprotein in the liquid lamella of dough enhanced the thermal stability of foams and contribute to superior quality of steamed bread. Results demonstrated that germinated wheat could be exploited as a functional ingredient with desirable technofunctionality by modification of the components. [ABSTRACT FROM AUTHOR]

The use of Fourier transform infrared spectroscopy (FTIR) allowed for the determination of changes in the secondary structure of gluten network after model dough supplementation with selected phenolic acids. The model dough was supplemented with phenolic acids at the following concentrations: 0.05%, 0.1%, and 0.2% (w/w). Results obtained from amide I band analysis, revealed that addition of phenolic acids to the dough resulted in formation of ß-turns and antiparallel-ß-sheets at expense of pseudo-ß-sheets and hydrogen-bonded ß-turns. Analysis of the amide III band showed that the ß-sheet structures content increased at the expense of α-helices and ß-turns. The changes occurring within the OH stretching region after the addition of phenolic acids were minor. UV–Vis analysis revealed that the gluten samples, which were modified by hydroxycinnamic acids, displayed stronger antioxidant activity than the gluten samples modified with hydroxybenzoic acids. An additional functional group in the form of a hydroxyl group (-OH) also displayed a significant effect on antioxidant properties. As the mixing of model dough progresses, hydrophobicity of the gluten network increases, however, the changes were minor. The changes in hydrophobicity after phenolic acid supplementation were also minor. Obtained data indicated that phenolic acid interacted more with glutenin fraction than with gliadins. [Display omitted] • Acids induced formation of antiparallel-β-sheets and β-turns from pseudo-β-sheets. • Addition of phenolic acids had no effect on the gluten hydration level. • Phenolic acid led to increase in gluten-phenolic acid antioxidant properties. • Hydroxycinnamic acids-gluten complexes showed the strongest antioxidant capacity. • Phenolic acids interacted foremost with glutenins. [ABSTRACT FROM AUTHOR]

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation. [ABSTRACT FROM AUTHOR]

Structural changes of proteins in fresh noodles during mixing, resting, sheeting, and cooking were investigated. The protein structural changes were evaluated by measuring the protein content, molecular weight, thiol and disulfide contents, secondary structure, thermal properties, microstructure, and mean particle size. The protein content was not significantly changed during fresh noodle processing. The wheat protein molecular weight decreased from 66.2 to 22.0 kDa during the cooking process. The disulfide content increased during the mixing and cooking processes. Additionally, the cooking process caused an increase in the number of gluten protein absorption peaks in the FTIR analysis. The secondary structure was mainly composed of β-sheets, and their proportion decreased in the cooking process. Gluten proteins were demonstrated to have high thermal stability with an average denaturation temperature of 84.9°C. There was a significant relationship between the gluten protein properties and fresh noodle processing. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of ozone treatment on chemical and physical properties of wheat (Triticum aestivum L.) gluten, glutenin and gliadin. Methods: Wheat proteins isolated from wheat flour were treated with ozone gas. The physical and chemical properties of gluten proteins were investigated after treatment with ozone gas, with 5 g/h produced as a function of time (0, 30, and 60 min) in the study. To check whether the process of ozonation promoted changes in the quality of gluten proteins, sulfhydryl groups (SH), differential scanning calorimetry (DSC), secondary structure, SDS-PAGE, and rheology analyses were performed. Results: Sulfhydryl group contents of wheat proteins ranged from 1.1 to 7.12 μmol/g. Sulfhydryl group content for all ozonated proteins was significantly lower than that of the control samples. Gluten proteins showed reduced SDS-PAGE band intensities of both high (HMW) gluten and glutenin subunits with increasing ozone gas treatment. The denaturation temperatures (Td) of ozonated gluten proteins were higher (99.80-106.79 °C) and the enthalpies of the ozonated gluten proteins were lower than those of the control samples. The storage moduli (G') and loss moduli (G") of gluten and glutenin tended to increase from 7.84 to 10.20 KPa and 43.19 to 48.28 KPa, and from 3.33 to 4.06 KPa and 20.74 to 22.56 KPa, respectively, as ozone exposure increased from 0 to 30 min. Conclusion: Ozone gas can oxidize wheat proteins. Exposing wheat proteins to ozone gas for an extended time (60 min) deteriorated wheat protein quality. [ABSTRACT FROM AUTHOR]

Modern agriculture relies on an integrated approach, where chemical treatment is reduced to a minimum and replaced by biological control that involves the use of active microorganisms. The effect of the antagonistic yeast-like fungus Aureobasidium pullulans on proteins and bioactive compounds (alkylresorcinols, sterols, tocols and carotenoids) in winter wheat grain and on the colonization of wheat kernels by fungal microbiota, mainly Fusarium spp. pathogens, was investigated. Biological treatment contributed to a slight increase contents of tocols, alkylresorcinols and sterols in grain. At the same time, the variation of wheat grain proteins was low and not significant. Application of A. pullulans enhanced the natural yeast colonization after six months of grain storage and inhibited growth of F. culmorum pathogens penetrating wheat kernel. This study demonstrated that an integrated approach of wheat grain protection with the use of the yeast-like fungus A. pullulans reduced kernel colonization by Fusarium spp. pathogens and increased the content of nutritionally beneficial phytochemicals in wheat grain without a loss of gluten proteins responsible for baking value. [ABSTRACT FROM AUTHOR]

Wheat kernels were subjected to microwave treatment, and the proteins were characterized by size exclusion high-performance liquid chromatography (SE-HPLC) and sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). Using this process, the proteins polymerize, forming intermolecular bonds among the same classes of proteins. Furthermore, the polymerization occurs only through disulphide bonds. Although SDS–PAGE did not show any differences for either the number or intensity of protein bands between flour samples before and after microwave treatment, gliadins from treated flours showed significantly reduced cross-reactivity with the R5 antibody. Moreover, the gluten became soluble in an aqueous saline solution, and it was not possible to isolate it using the Glutomatic apparatus. However, the treated flour, in the presence of water, was able to form dough and leaven and produce bread. [ABSTRACT FROM AUTHOR]

Unstable breadmaking quality of wheat due to environmental influence has been a problem for Norwegian milling industries. Large variation in gluten quality was observed from field trials with Norwegian winter wheat conducted in several locations between 2005 and 2013. Moreover, extremely poor gluten quality was observed in several locations in the 2007 and 2011 season, and indicated almost complete loss of breadmaking quality. To investigate the environmental factors which cause extremely weak gluten, gluten proteins were characterized in samples selected within the 2011 season. The results revealed that the proportion of large glutenin polymers decreased in wheat samples with extremely weak gluten. Moreover, re-polymerization of large glutenin polymers, which normally occur during the resting period of a dough, did not take place in gluten prepared from these samples. Incubation of total proteins extracted from these samples in anin vitrosystem showed a drastic degradation of gluten proteins indicating protease activities. The origin of the proteases remains unclear; however, exogenous proteases derived fromFusariumspp. seem to play a key role for protein degradation, and thus causing severe quality deficiency. A genotypic difference was found between the two cultivars and one of them had higher resistance against the factors influencing gluten quality in negative way. [ABSTRACT FROM AUTHOR]

Following bread dough development can be a hard task as no reliable method exists to give the optimal mixing time. Dough development is linked to the evolution of gluten proteins, carbohydrates and lipids which can result in modifications in the spectral properties of the various fluorophores naturally present in the system. In this paper, we propose to use 3-D-front-face-fluorescence (3D-FFF) spectroscopy in the 250–550 nm domain to follow the dough development as influenced by formulation (addition or not of glucose, glucose oxidase and ferulic acid in the dough recipe) and mixing time (2, 4, 6 and 8 min). In all the 32 dough samples as well as in flour, three regions of maximum fluorescence intensities have been observed at 320 nm after excitation at 295 nm (Region 1), at 420 nm after excitation at 360 nm (Region 2) and 450 nm after excitation at 390 nm (Region 3). The principal components analysis (PCA) of the evolution of these maxima shows that the formulations with and without ferulic acid are clearly separated since the presence of ferulic acid induces a decrease of fluorescence in Region 1 and an increase in Regions 2 and 3. In addition, a kinetic effect of the mixing time can be observed (decrease of fluorescence in the Regions 1 and 2) mainly in the absence of ferulic acid. The analysis of variance (ANOVA) on these maximum values statistically confirms these observations. Independent components analysis (ICA) is also applied to the complete 3-D-FFF spectra in order to extract interpretable signals from spectral data which reflect the complex contribution of several fluorophores as influenced by their environment. In all cases, 3 signals can be clearly separated matching the 3 regions of maximal fluorescence. The signals corresponding to regions 1 and 2 can be ascribed to proteins and ferulic acid respectively, whereas the fluorophores associated with the 3rd signal (corresponding to region 3) remain unidentified. Good correlations are obtained between the IC score values of the 3 signals and the fluorescence intensities in Region 1, Region 2 and Region 3. Ferulic acid addition increases fluorescence in Region 2 and decreases fluorescence in Region 1, probably via a reabsorption of the protein fluorescence by ferulic acid. These phenomena are less pronounced when glucose oxidase is present. The enzymatic oxidation of ferulic acid by the glucose oxidase-peroxidase association could explain some of these effects. [ABSTRACT FROM AUTHOR]

Background Gluten proteins are considered as quality determinants in cereal-based food product by forming the backbone structure of dough. Freezing technique has largely expanded the dough shelf life and brought revolutionary development to the bakery industry. However, deterioration of gluten network in frozen dough is one of the major factors leading to the quality loss of bakery products. During the manufacturing process of frozen dough, hydration with optimum mixing is the first and critical step to manage the control dough quality, followed by the freezing and frozen storage to achieve the long time storage of dough, which determines the final dough quality. Scope and approach Series of physicochemical alterations in gluten proteins occur upon the dough formation and frozen storage. Understanding these fundamental changes is important for the research community to propose more rational implementation of specific improvement principals for frozen dough. In this review, the physicochemical alterations of wheat gluten proteins are investigated from the perspectives of gluten and its component glutenin and gliadin. Key findings and conclusions A more structure-ordered, homogeneous and elastic gluten network is formed at the optimum mixing stage as a consequence of glutenin and gliadin interactions. Comparative studies in different model systems demonstrate that further frozen storage exerts detrimental effects on gluten proteins in diverse ways from both gluten proteins-water interactions and structure-functionality perspectives. [ABSTRACT FROM AUTHOR]

Durum wheat (Triticum turgidum L. subsp. durum) is one of the major crops in the Mediterranean basin, where water stress often occurs during grain filling which represents a critical stage for the synthesis and accumulation of storage proteins (gliadins and glutenins). The aim of the study is to evaluate, by two-dimensional gel electrophoresis (2DE SDS-PAGE), the storage proteins composition of two durum wheat cultivars (Ciccio and Svevo) cultivated in a growth chamber under two different water regimes (control and water deficit). At milk stage and physiological maturity, gluten proteins have been extracted and separated by 2DE SDS-PAGE. The analysis of the gels was performed by the software ImageMaster 2D Platinum (Amersham). The results showed differences in protein expression within the different gel regions between water regimes and cultivars; under water deficit the rate of protein accumulation was faster for all the protein regions, either at milk and physiological stage. Protein accumulation within high molecular weight (H) region resulted faster in Ciccio than in Svevo mainly in the control treatment. In the low molecular weight region between 48 and 35 kDa (L 48-35), the cultivar Ciccio showed a higher protein expression than Svevo. Furthermore under water deficit a marked increase in H region volume and a decrease in the L 48-35 region was observed only for Svevo; instead in Ciccio no change was observed showing this cultivar a greater stability on changing water regime. Further studies by the use of mass spectrometry are necessary to identify specific peptides relative to drought stress during grain filling as well as to investigate the relationships with technological quality.

To clarify the interactions among curdlan, starch and gluten, curdlan-induced rheological, thermal and structural properties of wheat dough during heating were investigated. When heating temperature exceeded 60 °C, 0.6% curdlan increased the stiffness of dough with a maximum storage and loss modulus. For starch, the increase of curdlan (0–0.9%) inhibited its gelatinization, and the peak and breakdown viscosity decreased by 28.1% and 24.5%, respectively, accentuating the dough strength. Regarding gluten, excessive curdlan (0.9%) delayed the thermal denaturation and increased the content of exposed sulfhydryl group (0.64 mmol/g for control dough vs. 0.83 mmol/g for treated dough, P < 0.05), resulting in the structural weakening of dough. Hydrogen bonds and hydrophobic interaction were involved in curdlan-gluten interactions at more than 75 °C. Some random coils of gluten were transformed into α-helix structure, which reduced the flexibility of the polypeptide chains. The microstructure confirmed the results of rheological properties that the dough containing 0.6% curdlan was more stable and denser (≥75 °C). In summary, during heating (>60 °C), the dough containing 0.6% curdlan was the most desirable with respect to viscoelasticity and strength, suggesting that it is possible to use curdlan to improve the processing characteristics of wheat dough. [Display omitted] • 0.6% curdlan enhanced the viscoelasticity of dough during heating. • Curdlan inhibited the swelling and gelatinization of starch granules. • Curdlan was integrated into the gluten matrix and adhered to starch granules. • Curdlan interfered with the formation of disulfide bonds in gluten proteins. [ABSTRACT FROM AUTHOR]

The addition of polyphenols to wheat dough modifies the structure and mechanical properties of the gluten network. The aim of the study was to identify changes in the secondary and tertiary structure of gluten network induced by selected hydroxycinnamic and hydroxybenzoic acids with using FT-Raman spectroscopy. Phenolic acids were added to the model dough in concentrations of 0.05%, 0.1%, and 0.2% (w/w). Model flour consist of commercially available wheat starch and wheat gluten in proportions 80:15 (w/w). All phenolic acids caused similar alterations in the secondary structure of gluten proteins in terms of the creation of aggregated structures from α-helices, β-turns and hydrogen-bonded β-turns, although hydroxybenzoic acids induce more structural changes like pseudo-β-sheets. Furthermore, dough treatment with hydroxycinnamic derivatives results in faster dough breakdown than hydroxybenzoic acids. These results indicate that hydroxycinnamic acids have stronger interactions with gluten network in comparison to hydroxybenzoic acids. Further analysis showed that tryptophan residues were more buried in samples with phenolic acids containing methoxy groups. The interactions between phenolic acids and gluten proteins are complex, and they have been affected by the functional groups attached to the benzene ring as well as the concentration of phenolic acid and its size. Moreover, phenolic acids may primarily interact with glutenins. [Display omitted] • Hydroxycinnamic and hydroxybenzoic acids interact with gluten in different way. • Hydroxybenzoic acids cause more structural changes. • The presence of phenolic acids within dough during mixing induces dough breakdown. • Phenolic acids addition resulted in higher content of aggregated structures. • Interactions gluten proteins - phenolic acids affects mainly glutenins structure. [ABSTRACT FROM AUTHOR]