Cyanide contents of some Nigerian legumes and the effect of simple processing (original) (raw)

The cyanide contents of seeds of varieties of Phaseolus aureus, Vigna unguculata, Cajanus cajan and Canavalia gladiatus were studied. Results obtained show total cyanide contents of 381-1093, 285-1223, and 208-953 mg kg-1 dry weight of intact seed, testa and cotyledons, respectively, with testa having 3-5 times higher HCN than cotyledons in some cases. Soaking of seeds in water for 24 h led to appreciable losses in HCN, while boiling for 3 h caused drastic reduction (49-95%) in HCN. After boiling for 3 h, innocuous HCN levels were obtained with seeds previously soaked in water for 24 h and divested of testa. Thus soaking of bean seeds in water and subsequent removal of testa prior to boiling will decrease HCN in bean meals.