Influence of harvest date on glycoalkaloid contents of three potato varieties

The influence of potato variety, time of tuber harvesting and peeling operation was investigated on the alpha-solanine and alpha-chaconine contents of potato tubers of three Polish varieties: Aster-very early, Mila-middle-early and Bryza-middle-late. Samples of tubers were harvested in three different periods of time. Unpeeled and peeled tubers were subjected to freeze-drying. In the powders obtained, the contents of alpha-solanine and alpha-chaconine glycoalkaloids were determined by HLPC. Investigated varieties differed in respect of both contents of glycoalkaloids and the ratio of alpha-solanine to alpha-chaconine. The tubers of the early variety Aster, harvested in the I period of time, contained the highest amount of glycoalkaloids, while the tubers of the middle-late variety Bryza, harvested in the II and III periods, contained the lowest amount of glycoalkaloids. The peeling of tubers caused a decrease of alpha-solanine and alpha-chaconine contents in the investigated potatoes and this obscured the differences between varieties. The contents of these compounds in peeled tubers of studied potato varieties remained at a similar low level, regardless of the glycoalkaloid contents in tubers before peeling. (C) 2002 Elsevier Science Ltd. All rights reserved.