EFFECT OF PROCESSING ON THE CYANIDE CONTENT OF CASSAVA PRODUCTS IN FIJI

Abstract

In Fiji cassava (Manihot esculenta Crantz, Euphorbiaceae) is one of the most important root crops. According to the 2004 National Nutrition Survey, 59.2% of the Fijian population consumes cassava on a daily basis while 31% of the Indian population consumes cassava on a weekly basis. Substantial quantity of anti-nutrient factor cyanogenic glucoside, linamarine and a small amount of lotaustralin is also present in cassava that interferes with digestion and uptake of nutrients. This study was aimed at finding out the cyanide content of cassava products available and consumed in Fiji
Cyanide content of twelve cassava based food items with cassava as the main ingredient was tested for the cyanide content using the pictrate method. The absorbance was measured in a spectrophotometer at 510 nm and the total cyanide content in mg HCN equivalents/kg fresh weight = ppm calculated by multiplying the absorbance by 396. The results were analyzed by SPSS by one way ANOVA and pair-wise comparison was made post hoc using Tukey t-tests.
The results showed that the cyanide content ranged from 2.21 to 44.14 mg HCN equivalent/kg. Grated cassava products exhibited lower cyanide content as compared with minimally processed cassava products and fried cassava products. Since cyanogenic glycosides are water soluble, a higher percentage of cyanides are removed when cassava products are processed in water. Fried cassava products had higher levels of cyanide as it is not soluble in lipids/oil, hence less cyanide is lost during frying.