A modified microdiffusion assay with solid-state detection for the determination of total cyanogens (CNp) in cassava flour. Comparison to the method of OʹBrien et al. (1991)

A simplified assay for quantitative determination of the total cyanogen content of cassava flour was developed. It relies on solid state detection after microdiffusion of released HCN from an acid flour extract. The reading of the solid state colour reaction was done by a microplate reader, but may also be done by means of a portable reflectometer. Positive test reactions are stable provided the reacted sheets are stored in the dark. The new method has been compared to the standard method of OʹBrien et al. (Journal of the Science of Food and Agriculture, 56, 277–289, 1991), and give identical results for levels of total cyanogens higher than approx. 5 mg kg−1.