Aspects of proteins in chinese and British common (hexaploid) wheats related to quality of white and yellow chinese noodles

Abstract

Traditional white Chinese noodles were made with 70 % extraction rate flours from 40 Chinese wheats and eight British wheats including Brock, a variety of very poor breadmaking quality. Mean 1000 kernel weights were similar in Chinese and British wheats, but the former had on average 2·5 % more protein than the latter. SDS sedimentation values were significantly correlated with maximum cutting stress and maximum compression stress of cooked white noodles, but protein contents did not relate to either quality parameter. When yellow noodles were made from 11 Chinese wheats and the British wheats, the Chinese wheats and Brock gave noodles distinctly different compared with those from the other British wheats, but in both sets SDS values were highly correlated with maximum cutting stress and maximum compression stress. This difference was thought to be due, at least partially, to the effect of alkali used in the yellow noodles which increased starch gelatinisation temperatures by 3·8-4·3 °C in Chinese starches and by 4·6–4·9 °C in British starches, but did not affect gelatinisation enthalpy. The Chinese wheats were classified into three groups according to the presence of γ-gliadin bands 41·0, 44·5, 45·0 and 45·5 separated by electrophoresis on aluminium lactate buffered gels (pH 3·1). Bands 44·5 and 45·0 were generally associated with strong gluten and band 41 ·0 with weak gluten, as in non-Asiatic common wheats, but an additional band 45·5 was also associated with weak gluten in most Chinese wheats.