The total glycoalkaloid concentrations in white- (cv Pentland Hawk), pink- (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 μmol m−2 s−1. Regardless of cultivar, glycoalkaloid concentrations were increased after light exposure compared with initial concentrations. Glycoalkaloid concentrations fluctuated with time and continuous accumulation of glycoalkaloids with time was not demonstrated. Glycoalkaloid synthesis was maximal in the sequence cv Kerrs Pink<cv Pentland Hawk<cv Desiree. Exposure to daylight altered the ratio of α-chaconine: α-solanine in tubers of cv Desiree but not those in cv Pentland Hawk and Kerrs Pink. Glycoalkaloid concentrations in all cultivars were higher than the recommended food safety level, this was reached after 8 days in cv Kerrs Pink and Desiree and at 13 days in Pentland Hawk. The implications of these results in terms of food safety are discussed.
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