Simple picrate paper kit for determination of the cyanogenic potential of cassava flour

• Published in: Journal of the science of food and agriculture 1998-01, Vol.76 (1), p.39-48
• Main Authors: Egan, Sylvia V, Yeoh, Hock Hin, Bradbury, J Howard
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; cassava flour; cassava roots; cyanide; cyanogenic potential; Food toxicology; Medical sciences; picrate paper; semiquantitative method; simple kit method; Toxicology
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/(SICI)1097-0010(199801)76:1<39::AID-JSFA947>3.0.CO;2-M

A simple picrate paper kit method was developed for the semiquantitative determination of the cyanogenic potential for cassava flour. The method involved the addition of linamarase and pH 8 phosphate buffer (absorbed in a filter paper disc) to 100 mg of flour +0·5 ml water placed in a small vial. A rectangle of yellow picrate paper attached to a plastic strip was added and the vial capped and left overnight. The yellow paper changed colour towards brown and its colour was compared with that of a standard colour card with 10 shades of colour which corresponded with cyanogenic potentials of 0–800 mg HCN equivalents kg−1 flour (ppm). To obtain a more accurate measure of cyanogenic potential (±20%) the paper was eluted with water and the absorbance measured at 510 nm. The cyanogenic potential in ppm was determined from a calibration graph. The methodology is available in kit form. The simple method may be used in the field by a relatively unskilled person. The more accurate method requires a spectrophotometer and is suitable for use in simple laboratories in developing countries. © 1998 SCI.