Winged Bean (Psophocarpus tetragonolobus) Tannin Level, Phytate Content, and Hemagglutinating Activity

Abstract

Sixteen varieties of winged bean (Psophocarpus tetragonolobus) were assayed for tannin level, phytate content, and hemagglutinating activity. Tannin level ranged from 0.3 to 7.5 mg of D-catechin/g of bean, phytate content ranged from 6.10 to 7.52 mg of phosphorus/g of bean, and the hemagglutinating activities of the surveyed beans ranged from 40 to 320 hemagglutinating units/mg of bean. It is found that none of the winged bean varieties surveyed contains amounts of tannin or phytate that may be nutritionally harmful. The winged bean hemagglutinating activity is stable to dry heat treatment (100 °C, 2 h) but could be destroyed completely by 5-min autoclave treatment at 120 °C, 1.05 kg/cm2. © 1983, American Chemical Society. All rights reserved.