Hearth bread baking quality of durum wheat varying in protein composition and physical dough properties.

摘要

Breadmaking quality of 30 durum wheat genotypes originating from 10 countries and cultivated over 2 yr in Western Canada was compared. 3 genotypes were gamma-gliadin 42 lines and characterized by low gluten index values, weak gluten characteristics and low levels of unextractable polymeric protein (UPP). The remaining 27 genotypes were gamma-gliadin 45 types and exhibited a wide range of gluten index, dough strength and UPP values. High-mol.-wt. glutenin subunit (HMW-GS) patterns identified among gamma-gliadin 45 genotypes included 6 + 8, 7 + 8, 7 + 16, 14 + 15, 20 and 2*, 20. The HMW-GS genotypes 6 + 8 and 7 + 8 tended to be strong, while HMW-GS 20 genotypes were generally weak. Genotypes displayed diverse baking quality when baked into hearth bread using a lean-formula, long-fermentation, straight-dough process, with some genotypes having similar or slightly superior loaf vol. and bread characteristics compared with a high-quality bread wheat (control) flour. In terms of HMW-GS groups, genotypes possessing subunit 20 had the poorest and those with 6 + 8 and 7 + 8 the best baking quality. Bread quality characteristics, including loaf vol., showed good correlation with gluten index and UPP. A combination of dough elasticity and extensibility, as determined by farinograph, alveograph and small-scale extensograph studies, was required for optimum durum wheat breadmaking performance.