In vitro protein digestibility of flours and cooked pastes prepared from white common beans (Phaseolus vulgaris L. cv. Yukitebou)

Dehulled or whole white common beans were crushed and milled, then cooked with or without enzyme treatment. Protein digestibility of the flour and cooked pastes were examined by in vitro pepsin assay. Heat-crushing at 200 degrees C prior to the milling process appeared not to affect the digestibility of proteins in the flour. Phaseolin, which is the most abundant protein of common beans, lectin, and several minor components showed resistance to pepsin digestion. In cooked pastes, the basic subunit of legumin was remarkably tolerant to pepsin digestion. Using amylase/protease treatment during paste cooking, most of the proteins were degraded, but those that remained in the pastes as well as used enzymes seemed to be resistant to pepsin.