The Safety of Dark, Moulded Casava Flour Compared with White - a Comparison of Traditionally Dried Cassava pieces in north-east Mozambique.

Abstract

Fresh cassava roots (9) were split into segments to obtain pieces with similar levels of cyanogenic glucosides. From each root, one segment was deep-frozen immediately and analysed to serve as a reference. Remaining segments were dried and stored for 8 months under traditional household conditions in rural north east Mozambique. In these pieces, a varying extent of fungal growth occurred. They were ground and analyzed individually for moisture, cyanogenic potential and cyanohydrins plus HCN, pH, brightness, aflatoxins and the number and genus of fungal propagules. Mean (+SD) initial cyanogenic potential was 399 (+273) mg CN equivalent per kg on dry weight basis. By the traditional processing and storage a considerable (range 92.3 - 99.5%) loss in cyanogenic potential was achieved. Levels of cyanohydrins plus HCN together ranged from 19 to 89% of the total cyanide. There was no correlation between the initial and residual cyanoigenic potential. However, darker flours had significantly lower levels of cyanogenic potential, as well as cyanohydrins plus HCN. Similarly, darker flours showed a higher pH. No aflatoxins could be detected. It is concluded that safety cassava flour cannot be judged by colour or extent of fungal growth. The Journal of Food Technology in Africa Volume 5 Number 1 (January- March 2000), pp. 19-21