GLYCOALKALOID CONCENTRATION OF POTATO-TUBERS FOLLOWING EXPOSURE TO DAYLIGHT

The total glycoalkaloid concentrations in white- (cv Pentland Hawk), p ink- (cv Kerrs Pink) and red- (cv Desiree) skinned potato tubers were measured following 21 days exposure to daylight using high-performance liquid chromatography. Average daytime irradiance during this period was 232 mu mol m(-2) s(-1). Regardless of cultivar, glycoalkaloid conc entrations were increased after light exposure compared with initial c oncentrations. Glycoalkaloid concentrations fluctuated with time and c ontinuous accumulation of glycoalkaloids with time was not demonstrate d. Glycoalkaloid synthesis was maximal in the sequence cv Kerrs Pink < cv Pentland Hawk < cv Desiree. Exposure to daylight altered the ratio of alpha-chaconine: alpha-solanine in tubers of cv Desiree but not th ose in cv Pentland Hawk and Kerrs Pink. Glycoalkaloid concentrations i n all cultivars were higher than the recommended food safety level, th is was reached after 8 days in cv Kerrs Pink and Desiree and at 13 day s in Pentland Hawk. The implications of these results in terms of food safety are discussed.