Simple wetting method to reduce cyanogen content of cassava flour

Abstract

Ten samples of cassava flour from Mozambique, Indonesia and Australia and one sample of gari from Mozambique were thoroughly mixed with water in the ratio 1:1.25. All the water was absorbed by the flour and the mixture was left in an open beaker at 30 °C. It was found that, providing that there was a reasonable amount of linamarase in the flour, the total cyanide content reduced about three-fold over 5 h. Addition of exogenous linamarase increased greatly the rate of breakdown of linamarin in the flour. There was no breakdown of linamarin from a gari sample at pH 4.2, but breakdown occurred when the pH was increased to 6 with buffer. The rationale for using this wetting method is that it is simple: the cassava flour is thoroughly mixed with water and allowed to stand in an open vessel for about 5 h, and then it is used for cooking. If the results in this brief paper are confirmed in the field and the method is acceptable to women, then it should decrease substantially the cyanide intake of those people in eastern, central and southern Africa who consume cassava flour, and thus reduce the incidence of cyanide poisoning and konzo.