The use of gluten proteins to predict bread and durum wheat quality

[摘要] English: Ethiopian cultivars and advanced lines of bread and durum wheat were studied for their grain quality characteristics under different environmental conditions. The influence of different protein fractions, ratios and subunits on bread making quality were determined by means of HPLC. Significant correlations across diverse genotypes and environments might indicate the potential use of these techniques in breeding programmes. SE-HPLC Bread wheat · The genotypes studied expressed genetic variability in most of the important quality traits. Protein levels across the two environments were relatively low. A decrease in protein content led to an increase in mixing time. Genotypes at the lowest protein site had the longest mixing times. · The higher protein site had higher average concentrations for all fractions extracted, except for SDS soluble and insoluble LMP. · Across the two environments, the SDS soluble and insoluble polymeric proteins had a highly significant influence on quality. · The number of correlations observed increased across environments compared to individual environments. · Higher significant correlations were observed between ratios of proteins compared to that found between individual proteins. SE-HPLC Durum · Similar results to bread wheat were seen for durum genotypes tested. The lower protein environment resulted in a lower protein content and increased mixing time. · The average concentrations for SDS soluble LPP and SMP and insoluble LMP, SMP, TUPP and LUPP were higher at the high protein potential site. · The number of correlations increased across environments, than when environments were considered individually. · The magnitude of the correlations increased across environments. · Higher significant correlations were observed between ratios of protein fractions and quality traits, notably the correlations between the ratio of SDS insoluble LPP:LMP and SPP:LMP with mixograph development time (0.545*** and 0.518***, respectively). · Durum has the potential of improvement for bread making quality. Bread and durum wheat · The average flour protein content was slightly higher for durum wheat, at the higher protein site, but similar at Motta. · The mixograph development time for both wheat types was longer at Motta, than at Adet, with the mixing time for durum slightly longer than that of bread wheat at Motta. · The durum genotypes had higher average SDS soluble and insoluble LPP and SMP fractions, at both environments, compared to bread wheat. · The opposite was true for LUPP and TUPP fractions, where the bread wheat genotypes had a higher average. · The LUPP fraction and the SDS insoluble SPP displayed a direct relationship with SDS sedimentation, continuously across environments. · The averages of baking quality traits for bread and durum wheat, with the exception of SDS sedimentation, did not differ extensively. This indicated the potential application of durum wheat for comparable breadmaking utility. RP-HPLC Due to the large amount of data generated by RP-HPLC, emphasis was placed on the general trends across entries and differences between entries were not discussed. Bread wheat · A total of 38 glutenin subunits (including minor peaks and unresolved shouders) were resolved. · Forty two bread wheat gliadin peaks were differentiated. · The environmental effect was visible in entries in both variation in quantity observed and as presence or absence of subunits. · Peaks/subunits correlating with baking parameters differed across different environments. This indicated sensitivity to environmental influences. · Some correlations occurred consistently, regardless of the differences in environment. · Significant polymeric-polymeric and monomeric-monomeric as well as polymeric-monomeric correlations were observed. These interactions need to be considered when determining functionality. Correlations might be due to indirect effects. · Stepwise multiple regression can assist in determining direct relationships. It also gives an indication of the interactions excisting between protein components. · The regression models indicated the individual proteins contributing to the quality trait. Some proteins were major contibutors, explaining 59% of the variation occurring in the parameter. The most important contributors to quality remained the glutenin subunits. Durum wheat · A total of 42 glutenin subunits (including minor peaks and unresolved shouders) were resolved. · Fifty one durum wheat gliadin peaks were differentiated. · Similar results to bread wheat were obtained for durum wheat entries. · Unlike the bread wheat results, specific durum subunits influenced more than one baking parameter simultaneously. · More interactions between the different protein subunits influencing specific traits were visible. No distinct patterns were visible between the subunit type and functional property.

[发布机构] University of the Free State