Spectrophotometric determination of cyanoglucosides in cassava

A new method is reported for determination of cyanoglucosides in cassava. The method is simple, rapid, and sensitive. Ten g cassava tuber is homogenized with warm (65-70 degrees C) 80% ethanol (1 + 6, w/v) to extract cyanoglucosides (CNG). The ethanol is evaporated, and an aliquot of the extract (0.1-0.2 mL) is incubated with added linamarase in pH 6.0 phosphate buffer for 15 min at 30 degrees C. The reaction is stopped by adding 0.2 N sodium hydroxide, the solution is neutralized, and cyanide is estimated by adding chloramine T and barbituric acid-pyridine reagent and measuring the absorbance at 570 nm. Complete CNG extraction and rapid inactivation of endogenous linamarase is possible with 80% ethanol. There is no interference from extractives in the linamarase reaction or in the estimation of cyanide. Recovery of added linamarin (as cyanide) is 98% by this assay. The minimum detection limit of cyanide in the assay is 0.1 micrograms/mL.