Some Anti-nutritional Factors of Mature Sword Beans (Canavalia gladiata)

Abstract

The anti-nutritional factor evaluation of Canavalia gladiata seed flour indicated a high amount of phytic acid, which decreased with processing. The raw cotyledon fraction had the highest content of phytate (8.5 mgg I) whereas the dry-autoclaved cotyledon flour had only 4.3 mgg'. The seed coat contained an a-amylase inhibitor and a trypsin inhibitor. The presence of an a-amylase inhibitor in the seed coat was established for the first time. The trypsin inhibitor activity of whole seed flour and boiled whole seed flour was 4866 TIUg·l and 2745 TIUg·1 respectively. The raw cotyledon was devoid of any inhibitor activity. The molecular weight of the trypsin inhibitor was found to be around 90 kD. The raw whole seed extract indicated a decrease in the a-amylase activity by 924 UIL indicating the presence of an inhibitor. There was complete inhibition of a-amylase activity by the raw seed coat extract. In the boiled seed coat extract the a-amylase activity increased (284 UIL). The different enzyme inhibitor activities were due to separate components present in the seed.