Electrophoretic separation and properties of winged bean seed trypsin inhibitor

Separation of the major trypsin inhibitor protein from crude extracts of winged bean seeds (WBTi) was accomplished using a cathodic polyacrylamide disc gel electrophoretic system. The molecular weight of the WBTi protein was determined to be about 20 000. Winged bean seed extracts showed trypsin‐inhibiting (Ti) activity similar to soya bean seed extracts, but large genotypic differences of the Ti activity in winged beans were found. Preliminary studies on the effects of processing on WBTi indicate that aqueous extracts of WBTi are at least as heat‐labile as the Ti of aqueous extracts of soya bean seeds. Autoclaving winged bean seed meal prior to protein extraction resulted in considerable reduction of protein solubility.