Comparative Study of Different Processing Methods for the Reduction of Cyanide from Bitter Cassava Flour

Abstract

Bitter cassava (Manihot esculanta) is one of the most important staple root crops planted in Nigeria. Substantial quantity of anti-nutrient factor cyanogenic glucoside that interferes with digestion and injurious to human health is present in it. This work is aimed at comparing different processing methods in the reduction of Hydrogen cyanide from bitter cassava flour. The fermentation and mechanical pressing-fermentation processing methods were used in the reduction of cyanide cassava flour. The flour was produced from bitter cassava root obtained from the three geo-political zones of Niger state, Nigeria labelled as zone A (Bida), B (Minna) and C (Kontagora) respectively. Twenty samples from each zone were used for the study. The initial average cyanide concentrations in the roots from each political zone were 106.44mg/kg, 94.99mg/kg and 102.59mg/kg respectively. The fermentation processing method reduces the cyanide concentration level from zone A, B, and C to 6.35mg/kg, 5.57mg/kg and 7.16mg/kg while the mechanical pressing-fermentation processing method decreases it to 4.31mg/kg, 4.48mg/kg and 4.15mg/kg from the aforementioned zones respectively. The result of the two processing methods reduced the cyanide concentration to the barest minimum level required by World Health Organization (10mg/kg). The mechanical pressing-fermentation method removed more cyanide when compared to fermentation processing method.

Keywords: Cyanide, Fermentation, Manihot esculenta, Mechanical press-fermentation