Differential effects of cooking in open cups and in sealed cellophane bags on the residual cyanide content of moi-moi, a processed legume product.

Bean pastes from the black eyed bean (Vigna unguiculata), pigeon pea (Cajanus cajan) and Ife brown (V. unguiculata) were processed into a popular West African snack moi-moi, cooked in open aluminium cups and in sealed, thin, transparent cellophane bags. The residual total, free and bound cyanide levels of moi-moi from both processes were determined using a combination of enzymatic and colorimetric procedures. Results showed that in all cases, cooking of moi-moi in open aluminium cups caused retention of significantly higher (P<0.05) residual free cyanide than cooking in sealed cellophane bags. Loss of bound cyanide was unaffected by cooking procedure. These results suggest that cooking of moi-moi in cellophane bags reduces the risks of cyanide exposure from legumes.