Quantitative Estimation of Hydrogen Cyanide in Fresh and Cooked Tuber Parenchyma (Pulp) of Three Cultivars of Sweet Cassava Cultivars Grown in Some Parts of Benue State, Nigeria

Abstract

The amount of cyanide in fresh and cooked tuber parenchyma (pulp) of three cultivars of sweet cassava from two local government areas (LGA) of Benue state was studied. Cassava tubers were collected and carefully peeled to obtain the pulp. The fresh and boiled samples were adequately processed and treated with ninhydrin, Na 2 CO 3 and NaOH and the absorbance of the reaction product measured using UV-Visible spectrometer after construction of a calibration graph using standard cyanide solutions. The amount of cyanide in the fresh pulp varied with differences in cultivars ranging from White Dan-Warri Cultivar: (19.87 to 28.81) mg/kg; Obasanjo cultivar: (17.23 to 28.81) mg/kg and Red Dan-Warri Cultivar (8.23 to 19.31) mg/kg. Also, the cyanide content of cultivars from Oju LGA was generally higher than that of the cultivars from Gwer-east LGA. Cyanide content varied with the period of the day harvested in the order: Afternoon > Evening > Morning for all cultivars. Furthermore, cooking greatly reduced the cyanide content of all the sweet cassava cultivars but boiling was more effective than roasting with the cyanide removal increasing with increase in cooking time. The cyanide content of the tuber parenchyma of the sweet cassava cultivars was very low (<30 mg/kg) which is in agreement with reported values for sweet cassava. However, cooking at a reasonable time interval will further reduce their cyanide levels to further safe limits.