AN ENZYME-BASED DIPSTICK FOR THE ESTIMATION OF CYANOGENIC POTENTIAL OF CASSAVA FLOUR

An enzyme-based dip-stick for cyanogenic potential determination was c onstructed by gluing three pieces of chromatography paper impregnated with cassava leaf linamarase, phosphate buffer pH 8 and alkaline picra te solution, respectively, onto a plastic strip measuring 10 mm x 45 m m. Using different concentrations of linamarin as reference (equivalen t to 0.5-40 mu g HCN), the change in colour of the picrate paper was r eadily distinguishable. Beyond 40-80 mu g HCN, it was difficult to dif ferentiate the colour of the picrate paper with accuracy. For quantita tive estimation, the colour from the picrate paper was eluted with wat er and its absorbance measured at 510 nm. Using the dip-stick in conju nction with different types of reaction vessels, it was possible to de termine the cyanogenic potential (expressed as mg HCN kg(-1)) of cassa va flour. The method was simple to use. It could easily handle large n umbers of samples and it seems suitable for held work. (C) 1997 Elsevi er Science Ltd.