Breadmaking quality of selected durum wheat genotypes and its relationship with high molecular weight glutenin subunits allelic variation and gluten protein polymeric composition

Abstract

Twenty-seven durum wheat genotypes originating from different geographical areas, all expressing LMW-2 at Glu-B3, and five bread wheats were evaluated for flour mixing properties, dough physical characteristics, and baking performance. Gluten polymeric composition was studied using size- exclusion HPLC of unreduced flour protein extracts. As a group, durum wheats had poorer baking quality than bread wheats in spite of higher protein and total polymer concentrations. Durum wheats exhibited weaker gluten characteristics, which could generally be attributed to a reduced proportion of SDS-unextractable polymer, and produced less extensible doughs than did bread wheats. However, substantial variation in breadmaking quality attributes was observed among durum genotypes. Better baking performance was generally associated with greater dough extensibility and protein content, but not with gluten strength related parameters. Extensibility did not correlate with gluten strength or SEHPLC parameters. Genotypes expressing high molecular weight glutenin subunits (HMW-GS) 6+8 exhibited better overall breadmaking quality compared with those expressing HMW-GS 7+8 or 20. Whereas differences between genotypes expressing HMW-GS 6+8 and those carrying HMW-GS 7+8 could only be attributed to variations in extensibility, the generally inferior baking performance of the HMW-GS 20 group relative to the HMW-GS 6+8 group could be attributed to both weaker and less extensible gluten characteristics.