Trypsin inhibitor activity in the field bean (Vicia faba L.).

Wilson and McNab' reported an increase in live-weight and a reduction in pancreas size of chicks when field beans (Viciu fabu L.) were autoclaved at 120 "C for 30 min. Such effects may be due to the presence in the raw field bean of a trypsin inhibitor analogous to those found in the soyabean and other legumes. Information on the presence of trypsin inhibitors in the field bean and on growth of animals fed on heattreated field beans is meagre and contradictory. Some of the contradiction arises because the Indian bean Dolichos lablab has the common name field bean and some research into anti-nutritive factors in this bean has been reported under that common name.*s3 In this study the name field bean will apply only to Vicia f i b i . Borchers and Ackerson4 found no trypsin inhibitor activity ( t i a . ) in field beans. In further work5 rat growth was significantly increased from 1.58 to 2.12 g/day when field beans were autoclaved at 121 "C for 30 min, although the field bean sample used showed no t.i.a. Haemagglutinating activity in the field bean was reduced by autoclaving at 121 "C for 30 min,6 but the initial activity was low and unlikely to explain the growth response to autoclaving reported elsewhere.' N i t ~ a n , ~ contrary to other findings,' reported that growth rate and weight gain per unit of food eaten were both reduced when rats were fed on autoclaved field beans and that trypsin and chymotrypsin inhibitors were not destroyed by heat treatment. In this study the sample of field beans used in previous chick growth studies' is examined in vitro for evidence of t.i.a.