AMYLOLYTIC ACTIVITY IN STORED POTATO-TUBERS .1. ESTIMATION USING P-NITROPHENYLOLIGOSACCHARIDES

Methods for the estimation of amylolytic activity are reviewed. A procedure for the routine extraction of amylolytic activity from freeze-dried powder prepared from potato tubers is described. The extraction medium is buffered at pH 7.0 and contains glycerol, dithiothreitol, calcium chloride and the non-ionic detergent, nonidet P-40. Alpha-Amylase activity and exoamylolytic activity were estimated in crude extracts of potato tubers using the substrates, blocked p-nitrophenyl-maltoheptaoside and p-nitrophenyl-maltopentaoside respectively. These substrates are included in kits supplied by Biocon, (UK) Ltd to measure the alpha- and beta-amylase activity in cereals. The validity of using these kits for the determination of alpha- and beta-amylase activity in potato tuber tissue is discussed.