Simple method to reduce the cyanogen content of gari made from cassava

The lactic acid content of gari, was determined by pH titration to be about 10 g lactic acid/kg gari. As the size of the gari particles increased from 400 to >1000 μm their total cyanide content increased from 5 to 21 ppm. The acetone cyanohydrin content of gari samples exposed to ambient laboratory conditions of temperature and relative humidity gradually decreased by 58% in 38 weeks whereas linamarin in cassava flour is 100% stable for 6 months. Cyanogens could not be removed from wet gari samples at 30 or 50 °C and were only slowly removed by repeated heating at 100 °C and rewetting. By mixing equal weights of gari (pH 4.1) and low cyanide cassava flour (pH 6.5), wetting and heating at 50 °C for 5 h, the cyanide content was reduced by about one half. Wetting a gari/flour (1:1) sample with 1.5 times its weight of water and standing in a 1 cm thick layer in the sun for 4 h reduced the cyanide content by about one half. This treated mixture may be cooked to prepare stiff porridge with lowered cyanide content, and may help reduce tropical ataxic neuropathy in West Africa.