Gluten Composition Research Articles

Interrelationships of Protein Composition, Protein Level, Baking Process and the Characteristics of Hearth Bread and Pan Bread

Baking performance of hearth bread and pan bread were investigated using 10 wheat varieties with variable protein quality. For most varieties, samples were selected at two protein levels, approximately 11 and 13% (d.m.). The effects of flour quality on loaf characteristics were different for hearth bread compared to pan bread, where both protein quality and protein content affect loaf volume positively in an optimised baking test. Hearth bread is more complex as both the form ratio and loaf volume are critical external characteristics. When using fixed proving time, the form ratio was positively affected by dough resistance and mixing peak time at high speed mixing, and negatively affected by dough extensibility. Dough resistance and mixing peak time correlated strongly to the HMW glutenin composition, whereas dough extensibility was related to protein content. In contrast to the form ratio, loaf volume was positively affected by dough extensibility, whereas protein quality had no significant effect. This was seen both for doughs produced at optimal mixing time at high speed mixing (126 rev/min) and for doughs produced at fixed mixing times at low speed mixing (63 rev/min). When proving time was optimised to achieve a defined form ratio, flours of strong protein quality should be proved longer than flours of week protein quality, resulting in higher loaf volume for flours of the strongest protein quality. With respect to protein content, the positive effect of protein content on loaf volume was counteracted due to reduced proving time when aiming for a defined form ratio.

Baking Performance, Rheology, and Chemical Composition of Wheat Dough and Gluten Affected by Xylanase and Oxidative Enzymes

ABSTRACT:Baking trials were performed with six wheat doughs prepared with xylanase, peroxidase, or glucose oxidase (GOX), and their combinations. Judging dough properties, baking performance, bread volume, and crumb structure, the dough containing xylanase plus peroxidase performed best. Flow relaxation measurements with doughs indicated that peroxidases introduced new transient linkages, whereas glucose oxidase also introduced cross‐links permanent on long time scales. Rheological tests and chemical analysis revealed small differences between control and xylanase and/ or peroxidase containing gluten and more pronounced differences for GOX containing gluten. No evidence was found that xylanase specifically removed arabinoxylans from gluten or that peroxidase catalyzed the formation of covalent bonds between arabinoxylans and gluten proteins.

Protein Composition and Agglomeration Tendency of Gluten Isolated from European Wheats (Triticum aestivum L.) in a Batter System

Pilot scale isolation of gluten (with recovery of gluten on 400, 250, and 125 μ sieves) from flour prepared from six European wheat varieties (Apollo, Slejpner, Sperber, Camp Remy, Minaret, and Soissons) resulted in, on average, gluten yields of 9.6% (4.7−13.2% range). Gluten protein recoveries averaged 63.0% (34.5−85.7% range). Gluten yields and gluten protein recoveries were linearly related and increased when mixing times and baking absorptions required for optimal dough development of the parent flours increased, indicating that there is a relationship between the agglomeration properties of gluten proteins in a batter system and the optimal technological conditions necessary for processing the flours in breadmaking. The Osborne protein fractions in the gluten fractions were determined. The 0.05 M acetic acid soluble (glutenin) fraction was quantitatively the most important fraction (40−46% of gluten Kjeldahl nitrogen) while comparable levels of 70% ethanol soluble (gliadins) and 0.05 M acetic acid insoluble (residue protein) were found (17.9−22.3% of gluten Kjeldahl nitrogen and 22.0−29.0% of gluten Kjeldahl nitrogen for gliadins and residue protein, respectively). With decreasing pore size of the sieves, the level of glutenin in the gluten decreased while the level of gliadins increased. This indicates that, in gluten with good agglomeration properties, the level of glutenins is high and that the agglomeration properties of such proteins (i.e. their tendency to aggregate) strongly determines the agglomeration behavior of the gluten as a whole. Keywords: Gluten agglomeration; gluten composition; Triticum aestivum

Distribution of Carbohydrates in Gluten Fractions Isolated from European Wheats (Triticum aestivum L.) in a Batter System

Glucose represented 89% of the total carbohydrate of gluten isolated in a batter system from wheat cultivars exhibiting varying breadmaking qualities. Galactose, arabinose (Ara), and xylose (Xyl) were the remaining carbohydrates (ca. 10% of the total carbohydrate content), while mannose was present in minor quantities (<1%). After Pronase treatment ca. 43% of the Ara and ca. 52% of the Xyl originating from arabinoxylan (AX) could be solubilized, indicating the presence of water extractable as well as water unextractable AX. Arabinogalactan-peptide (AGP) and small amounts of β-glucan were also present. Water extractable AX with a low Ara-to-Xyl ratio (A/X) and thus a low degree of substitution preferentially are incorporated in the gluten network probably as a result of alignment between glutenin polymers and AX in the stirring direction. In gluten from cultivars exhibiting high gluten protein recoveries (see accompanying paper; Roels et al. J. Agric. Food Chem. 1998, 46, 1344−1349), the levels of total gluten associated nonstarch polysaccharides (TOTGANSP), expressed as a percentage of total flour NSP, were also high. It was postulated that the gluten proteins of such cultivars agglomerate despite the presence of NSP since the gluten fractions with the best agglomeration properties contained the lowest amount of NSP. In the aforementioned gluten fractions the AGP/AX ratio was also unusually high, indicating that the undocumented role of AGP in wheat gluten agglomeration may well be underestimated. Keywords: Gluten agglomeration; gluten composition; arabinoxylan; arabinogalactan; Triticum aestivum

Yielding ability, yield stability, and quality of exotic durum wheat germplasm in Sicily

AbstractA set of 20 accessions of durum wheat (Triticum turgidum L., durum group), which mostly included exotic landraces from various Mediterranean countries, and four Italian improved varieties were evaluated for grain yield in five environments and for quality traits in two environments of Sicily. Glutenin composition was also assessed electro‐phoretically on six seeds per entry. The cultivars differed (P ≤ 0.01) for yield, protein content and sodium dodecyl sulphate (SDS‐sed) sedimentation volume, in the presence of significant (P ≥ 0.001) genotype‐environment interaction effects. These effects were large for yield and moderately large for protein content relative to genotype main effects following estimation of variance components. Most exotic cultivars yielded comparably with, and some of them showed greater stability than, the best yielding Italian variety 'Simeto. Some exotic cultivars combined outstanding yield, protein content and SDS‐sedimentation values and represent therefore extremely valuable germplasm sources to broaden the local genetic base. The glutenin composition LMW‐2 and HMW 7 + 8 was positively associated with gluten quality. Six entries showed heterogeneous electrophoretic patterns, suggesting the presence of different genotypes within the cultivar.

Genetic control of some polymeric glutenin fractions in hexaploid wheat (Triticum aestivum)

AbstractReciprocal crosses were made between seven different hexaploid wheat genotypes. Hybrid kernels and their parents were used to determine the amount of polymeric glutenin fractions by size‐exclusion high‐performance liquid chromotography (SE‐HPLC) analysis. Quantitative aspects of the genetic control for various glutenin fractions were investigated through diallel cross analysis. The association between the potential effect on hexaploid wheat quality of various allelic types and the quantitative expression of the polymeric glutenin fractions was confirmed. Significant average heterosis effects were demonstrated for insoluble glutenin (pFi), total soluble and insoluble glutenin (pF1 + pF2 + pFi) and the ratio of soluble to insoluble glutenin, (pF1 + pF2)/pFi. Some genotypes showed significant positive or negative combining abilities and general reciprocal effects for the glutenin fractions studied. For gluten quality, ‘Qualital’ was the best combiner for determining an optimal glutenin composition (high values for pFi and pF1 + pF2 + pFi and low values for pF1/pF2 and (pF1 + pF2)/pFi, respectively). These results should be of great interest in breeding programmes aimed at improving hexaploid wheat quality.

Rheological Behaviour of Wheat Glutens at Small and Large Deformations. Effect of Gluten Composition

Glutens derived from two wheat cultivars with a known difference in bread making quality, i.e. cv. Katepwa (good) and cv. Obelisk (poor), were fractionated into gliadin and glutenin. Cultivar Katepwa gluten contained more glutenin than cv. Obelisk gluten. Reconstituted glutens were prepared by mixing, in different ratios, gliadin and glutenin fractions that originated from one gluten type or from both glutens. The rheological properties of these mixtures, when hydrated, were studied at small deformations in shear and at large deformations in biaxial extension. The reconstitution of gluten in its original glutenin/gliadin ratio produced a composite that had a somewhat higher resistance to deformation and was more elastic than the unfractionated gluten. This was true for both gluten types. However, the difference between the rheological behaviour of both reconstituted gluten types was comparable with that found between the native glutens. From measurements with glutens reconstituted at various glutenin/gliadin ratios, it appeared that the main factor determining the rheological behaviour of hydrated gluten is the glutenin/gliadin ratio. By interchanging the gliadin and glutenin fractions of the two glutens, it was shown that the source from which the fractions originated, particularly that of the glutenin fraction, was also important.

Une étude du rôle des gluténines de haut poids moléculaire chez les blés hybrides: effet sur la qualité en situation d'hétérozygotie

Thirty-three winter wheat hybrids produced using a chemical hybridizing agent and their 27 parents were compared for bread-making quality. The F1 was intermediate between the two parents for grain hardness, Pelshenke test and W of alveograph. Correspondence analyses and tree-based models showed strong associations between high molecular weight glutenin composition and Pelshenke or alveograph. For the Pelshenke test, the Glu-D1 encoded subunits were preponderant, and the effect of the alleles appeared additive between loci, as well as within locus. For the alveograph, Glu-B1 was the most important locus. Dominance effects appeared, involving the 7 + 8 allele associated with high values for tenacity and extensibility. Key words: Hybrid wheat, bread-making quality, high molecular weight glutenin, Pelshenke, alveograph, grain hardness

Relationships between different prolamin proteins and some quality properties in durum wheat

AbstractThe objective of this paper was to study the differences between some prolamin variants coded at the loci Glu‐3/Gli‐1, Glu‐1 and Gli‐A2 and their relative roles in durum‐wheat quality. F3 lines from four durum wheat crosses (‘Abadia’בMexicali’. ‘Oscar’בArdente’, ‘Oscar × Mexicali’ and ‘Alaga’בC. of Balazote’) were analysed for gliadin and glutenin composition by electrophoresis. Whole‐grain‐derived samples were analysed for SDS sedimentation (SDSS) value, mixing properties, and contents of protein and vitreousness. The glutenin patterns LMW‐2. LMW‐2− and LMW‐2 (CB) at Glu‐B3/Gli‐B1 were associated with better gluten quality than were LMW‐1 and LMW‐2*. The glutenin subunits LMW4 and LMW3 + 15 at Glu‐A3/Gli‐A1 and HMW‐1 showed better mixing properties than LMW7 + 12, LMW5 and the null phenotype. respectively. The HMW glutenin subunits 20 + 8 at Glu‐B1 showed a negative association with gluten quality, but the rest of the HMW glutenin subunits and α‐gliadins did not show any influence on gluten quality.Correlations between the results of the SDSS test and the mixograph were highly significant, but no correlation was found between these results and protein and vitreousness contents. The results are discussed in relation to the development of durum wheat varieties with improved qualities.

A Null Gli-D1 Allele with a Positive Effect on Bread Wheat Quality

Abstract The French wheat cultivar Darius (Da) has very good bread-making quality, even though it possesses the high M r glutenin subunit combination 2, 7 and 12, which is associated with poor quality, and a null allele at the Gli-D1 locus. Darius was crossed with three cultivars, Corin (Cor), Capitole (Cap) and Courtot (Cou), of poor, medium, and good quality, respectively. The three progenies (Cor × Da, Cap × Da and Da × Cou) were used to investigate the genetic basis of the good quality of Darius. Gliadin and glutenin compositions were analysed by acid polyacrylamide gel electrophoresis (A-PAGE) and SDS-PAGE, respectively, from half F2 grains, and the quality was evaluated using six technological criteria for the corresponding plants. The high M r glutenin subunit alleles of Darius produced a negative effect on quality. The null allele of Darius, characterised by the absence of the Gli-D1 encoded ω-gliadins, was associated significantly with higher dough tenacity P , and strength W (up to 40% in the Cor × Da progeny). Darius had a higher amount of B zone low M r glutenin subunits than the three other cultivars. The null allele of Darius reduced the dough extensibility in the two first progenies, and probably increased the ratio of aggregated glutenin to unaggregated gliadins. These results demonstrated that using only one locus breeders can improve particular quality traits.

A Study by Infrared Spectroscopy of the Conformations of Gluten Proteins Differing in their Gliadin and Glutenin Compositions

The conformations of gluten proteins extracted from three near-isogenic lines of the wheat cultivar Sicco, which differed in their high Mr glutenin subunit compositions, were studied by infrared spectroscopy. Whole gluten and gluten fractions prepared by sequential extraction were analysed in solution and in the doughy hydrated state by transmission and attenuated total reflectance spectroscopy, respectively. In the hydrated viscoelastic state, the β-sheet content, especially that of intermolecular β-sheet conformation, of gluten proteins was higher than that in solution. In viscoelastic gluten fractions, the proportion of intermolecular β-sheet increased as the glutenin content increased. In addition, the α-helix content was lowest and the intermolecular β-sheet content highest when disulphide bonds were reduced in the hydrated state because interactions between gluten polypeptides can be maximised under these conditions. These results suggest that the interactions between subunits in glutenin polymers and aggregates involve intermolecular β-sheets located in their repetitive domains or in the region of chain entanglements that are responsible for the viscoelastic properties of gluten proteins.

The Heat-Shock Response Relevant to Molecular and Structural Changes in Wheat Yield and Quality

When wheat coleoptiles or plants are subjected to a period of heat stress (e.g, at &gt; 35�C for 1 h or more), there is a reduction in normal protein synthesis, accompanied by de novo synthesis of the classical range of heat-shock proteins (based on radioactive tracer experiments) in virtually all parts of the plant. Study of coleoptile elongation rates indicates that this synthesis is related to a protective effect, whereby a preliminary heat shock provides a degree of protection against a later lethal shock. This thermotolerance is also associated with the appearance in coleoptiles and roots of a small peptide (detected without radioactive labelling) whose amino acid sequence (12 residues) is the same as the N-terminal sequence of the alpha- and beta-gliadin proteins of the endosperm. Heat stress during grain filling leads to important changes in the synthesis of gluten proteins with reduced synthesis of the high molecular weight (HMW) subunits of glutenin, and continuing synthesis of other gluten proteins, particularly various gliadin proteins. This latter group of polypeptides is thus presumed to be acting as heat-shock proteins, and indeed, multiple heat-shock elements are present in the published sequences of representative genes, up-stream of the coding regions. HPLC analysis (with or without radioactive labelling) shows that there is a resulting change from the normal balance of gluten polypeptides immediately after the shock as well as in the mature grain. As a result, there is a lower proportion of large-sized aggregates of glutenin and weaker dough properties. This scenario indicates that it should be possible to identify genotypes that would be tolerant to stressrelated variations in quality by analysis of gluten composition and, at the gene level, by screening for heat-stress elements in the genes encoding HMW-glutenin subunits. In addition, heat stress modifies the particle size distribution of the starch fraction of mature grain, producing an increase in the proportion of large (A-type) starch granules. No change in chemical structure was detectable as a result of heat stress.

Electrophoretic protein analysis for the identification of doubled haploid 1A?1R, 1B?1R wheat-rye double translocation lines and for the assessment of their genetic stability

Eighteen available doubled haploid wheat lines with a cytologically proven 1A-1R, 1B-1R double translocation, which where derived via anther culture from four crosses of the 1A-1R wheat-rye translocation cv "Amigo" with several 1B-1R wheat-rye translocation forms, were subjected to electrophoretic seed protein analysis. Besides, the five parents used in the crosses and some other wheat cultivars and doubled haploid lines (19 with a 1B-1R single translocation, 10 with a 1A-1R translocation and 7 without any 1R translocation) were also included in the investigation. It was found that the gliadin patterns visualized after SDS polyacrylamide gel electrophoresis of alcohol-soluble seed protein extracts can differentiate not only 1B-1R and 1A-1R translocation forms from wheats without any 1R-translocation chromosome, but also 1B-1R and 1A-1R wheats from each other. Moreover, 1A-1R, 1B-1R double translocation lines can be distinguished as well due to characteristic differences revealed between 1A-1R and 1B-1R translocation forms. Thus, all of tested dh1- and dh2-grains of the double translocation lines showed the expected doublet: the 1A-1R translocation ("Amigo")-typical rye band and the 1B-1R translocation ("Kawkas")-typical rye band. Consequently, gliadin patterns estimated after SDS electrophoresis may be used as markers for the fast detection of the desired 1A-1R, 1B-1R double translocation forms among 1A-1R single translocation lines, 1B-1R single translocation lines and lines without any 1R-translocation in the progenies of appropriate crosses. Furthermore, by means of gliadin tests on the dh2-generation the excellent stability of the double translocation 1A-1R, 1B-1R during more than one propagation phase has been proven. Estimations of high-molecular weight (HMW) glutenin subunits coded by 1A and 1B chromosomes are compatible with the double translocation constitution. A few deviating results can be explained by crossing-over events. Seed protein analysis revealed that it is possible to produce 1A-1R, 1B-1R double translocation lines with good glutenin compositions provided that adequate favourable parents are used.

TEXTUROMETER AS A TOOL FOR STUDYING VARIETAL DIFFERENCES IN WHEAT FLOUR DOUGHS AND GLUTEN PROTEINS

The General Food's Texturometer has been used for studying the differences in wheat flour doughs prepared from 11 Indian wheat varieties of known gluten composition. The quantities of residue proteins in these varieties and the ratios of residue proteins over gliadins and glutenins were found to show high positive correlation with texturometer hardness and areas of first and second peaks. Adhesiveness was found to show high negative correlations. Of the gluten proteins only glutenins showed varietal differences i.e., the hardness and the areas of the first and the second peaks were found to increase from weak to strong varieties. The gliadins and the residue proteins of the varieties studied were found to be similar. Only gliadins were found to have adhesive character.

Puffing and Textural Characteristics of Chapati in Relation to Varietal Differences in Gluten Composition

ABSTRACTChapaties made from different wheat varieties differ in puffing and textural characteristics. These differences have been found to be related to the relative quantities of gliadins, glutenins and residue proteins in respective glutens. Wheat varieties having about equal quantities of gliadins, glutenins and residue proteins give fully puffed soft and pliable chapaties. Wheat varieties having more of residue protein give leathery chapaties and varieties having more of gliadin give relatively stiff chapaties. Applications of Warner‐Bratzler shear press for evaluating chapati texture is discussed.

Relationships between Australian wheats on the basis of pedigree, grain protein composition, grain quality and morphology

A procedure using numerical analysis has been devised for illustrating ancestry relationships. It has been applied to 60 wheat cultivars recently grown in Australia. The program also permits the grouping of parents to indicate those that are often used in combination. The network illustrating pedigree relationships between these cultivars corresponded closely to a second network which illustrated phenotypic similarities (morphology of plants, heads and grains, agronomic characteristics, grain quality and gluten composition). The specific attributes that most closely followed pedigree relationships were identified in this set of wheats. These procedures thus provide a basis for evaluating the role of pedigree in observed associations between phenotypic characteristics.

Stretchability of Wheat Gluten in Relation to Gluten Composition and Varietal Differences

Stretching characteristics of glutens of wheat varieties K 68 (strong), HD 4530 (medium strong) and sonalika (weak) were studied. The resistance to stretching was found to decrease from K 68 to HD 4530 to sonalika. Both quantitative and qualitative factors contributed to this difference. Qualitatively, the glutenin of sonalika was found to be different from the glutenins of K 68 and HD 4530. The gliadins and the residue proteins of all three varieties were apparently similar.

Note on the determination of maximum amount of cereal storage protein in foods.

AbstractThe maximum amount of cereal storage protein is determined in a ‘gluten‐free’ starch from the relation between the amino acid composition of gluten and ‘glutenfree’ starch. The starch contains 0.12% (w/w) protein and the amount of gluten proteins was not more than 0.05% (w/w).

Allelic variation in HMW glutenins in Spanish wheat landraces and their relationship with bread quality

The allelic variation of high molecular weight glutenins as principal determinants of bread quality has been analyzed in 165 Spanish wheat ( Triticum aestivum ssp. vulgare L.) landraces provided by the Plant Genetic Resources Centre. The identification by standard electrophoresis techniques has been supported by a new PCR screening method, allowing the identification of the 2•• glutenin subunit from the Glu-A1 locus in some landraces. The relation of high molecular weight glutenins and bread quality has been evaluated by SDS-sedimentation tests and mixographs. A positive influence on quality has been found for the 2•• glutenin subunit from the Glu-A1 locus, pairs 7 + 8 and 13 + 16 from the Glu-B1 locus, and pair 5 + 10 from the Glu-D1 locus. The presence of a wide range of values for quality traits in landraces with the same high molecular weight glutenin composition points to the possible influence of other prolamins such as the low molecular weight glutenins. Their influence on bread quality will be assessed in future studies. A complete description of the high molecular weight glutenin composition and quality values of all the landraces analyzed in this study is provided for use in wheat breeding programs.

Effect of Environment on Wheat Gliadin

CHEMICAL and physical investigations have shown that gluten composition differs from one wheat variety to another1–5. The total protein as a percentage of the weight of grain of a particular variety is affected by environmental factors and may be twice as great in some samples as in others grown in different conditions. Variations of this kind within a variety can result in an alteration in the proportions of the broad protein classes6,7 and could alter the distribution of components within classes. The work reported here was designed to test as rigorously as possible whether the second kind of change occurs within the gliadin class of proteins. It is desirable to know whether or not this type of change can occur if information on the composition of the gliadin is to be readily applicable to genetic investigations of inheritance of wheat quality.