Effects of heat treatments on trypsin inhibitor and hemagglutinating activities in winged bean

The effect of different heat treatments on inactivation of trypsin inhibitor and hemagglutinin of winged bean was investigated. Trypsin inhibitor extracted from winged bean meal was stable at 60 °C for 60 min. At 80 °C, the activity of the extracted inhibitor decreased by 25% within 5 min, and continued to decline gradually to a loss of 45% of activity after 30 min. When the extracted inhibitor was incubated at 100 °C, it exhibited a triphasic pattern of inactivation. The winged bean extract incubated at 60 °C lost 60% of its hemaggluinating activity within 30 min. At 80 °C, there was a complete loss of activity within 5 min. The microwave treatment to winged bean meal had no effect on trypsin inhibitor or hemagglutinating activities in the meal. However, infrared treatment to winged bean seeds for 60 seconds was effective in destroying most of the trypsin inhibitor and hemagglutinating activities. Autoclave treatment (120 °C at 15 lb pressure) for 10 min inactivated trypsin inhibitor and hemagglutinin in winged bean meal almost completely. Cooking of presoaked beans in boiling water for 30 min was effective in destroying most of the trypsin inhibitor and hemagglutinating activities.