Effect of selected vegetable oils on the cyanide content of cassava (Manihot esculenta Cranz.)

Abstract

The cyanide content in dried cassava cake (garri) in two varieties of the tubers (Tropical Manoic Selection 1 and Tropical Manoic Selection 91954) treated with palm oil, groundnut oil and coconut oil were determined enzymically. Results obtained from the study revealed that treatment of cassava mash with the  vegetable oils yielded about 99.8% reduction in the total cyanogenic content at seven days of fermentation. From an initial concentration of 10.35 mg HCN eq/mg in the sweet variety of fresh cassava tubers (Tropical Manoic Selection1), the cyanogenic content at the end of fermentation period was reduced to 0.02500, 0.02550 and  0.0253 mg HCN eq/mg by palm oil, groundnut oil and coconut oil respectively. Similarly, the bitter cassava variety (Tropical Manoic Selection 91954) was reduced from 14.54 mg HCN eq/mg to 0.03080, 0.02520 and 0.02560 mg HCN eq/mg by palm oil, groundnut oil and coconut oil respectively. The vegetable oils increased the temperature of grated cassava varieties to allow breakdown of cyanogenic glycosides and for easy volatilisation after processing into garri.

Keywords: Cassava, Cyanide Content, Vegetable Oils, Palm Oil, Groundnut Oil, Coconut Oil.