Electrophoresis studies for determining wheat-soy protein interactions in dough and bread.

摘要

Interactions between soy proteins and wheat proteins after dough mixing and breadmaking were studied. Protein extracts from gluten and breadcrumbs prepared with mixtures of wheat flour and enzyme-active full-fat, heat-treated full-fat or enzyme-active defatted soy meal, and commercial isolated soy proteins were analysed by electrophoresis. Different buffer systems with specific chemical action on proteins were used to investigate the types of forces between soy and wheat proteins in gluten and breadcrumbs. The presence of protein bands of similar mol. wt. to soy proteins in gluten fractions after intensive dough washing indicated association between these proteins. Non-reduced wheat-soy gluten proteins contained higher amount of SDS-soluble protein aggregates than wheat gluten. Results suggest that soy and wheat proteins interact by means of noncovalent and covalent (disulfide) bonds and that the extent of their interaction depends on the soy protein state.