Saponin content and trypsin inhibitor activity in processed and cooked pigeon pea cultivars

Four high-yielding varieties of pigeon pea namely UPAS-120, Manak, JCPL-151. ICPL-87 had considerable amounts of antinutrients i.e. saponins and trypsin inhibitors. Saponin content of these unprocessed cultivars ranged from 2164 to 3494 mg/100 g. There were significant varietal variations in trypsin inhibitor activity (1007-1082 TIU/g) of these pigeon pea cultivars. Some simple, inexpensive and easy-to-use domestic processing and cooking methods, namely, soaking (6, 12, 18 h), soaking (12 h)-dehulling, ordinary cooking, pressure cooking and germination (24, 36, 48 h) were found to be quite effective in lowering the level of saponins and trypsin inhibitors in all the pigeon pea cultivars. Pressure cooking of soaked and dehulled seeds lowered the content of saponins to a maximum extent (28 to 38%) followed by ordinary cooking of soaked and dehulled seeds (28 to 35%), soaked dehulled raw seeds (22 to 27%) and 48 h germinated seeds (15 to 19%). Loss of TIA was marginal due to soaking but ordinary as well as pressure cooking of unsoaked and soaked-dehulled pigeon pea seeds reduced the TIA drastically. Pressure cooking of pigeon pea seeds completely destroyed the TIA while it was reduced to the extent of 86-88% against the control in 48 h pigeon pea sprouts.