A modification of the enzyme-chromogen method for the determination of low levels of starch in plant material.
Davie S. J.
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
Journal of the Southern African Society for Horticultural Sciences 7 : 35-38
Abstract : Methods of starch analysis are discussed and factors giving rise to errors in the quantification of starch were investigated. A method based on the AOAC method was adapted to give more accurate values for starch in plant material, with particular reference to samples with relatively low levels (less than 5%). Initial tests were performed on guava stem cuttings. Based on these studies a method was recommended which uses 500-mg aliquots of milled sample material, an autoclave procedure for gelatinizing the starch in the sample, amyloglucosidase as the starch hydrolysing enzyme and an enzyme-chromogen solution containing 4-amino-antipyrine as the colour reagent for glucose determination. Interfering substances are removed with fat-free casein powder as an adsorbent. This method was tested on mango, avocado, orange, banana, pecan and guava samples (vegetative material).