Variation in glycoalkaloid concentration of potato tubers harvested from mature plants

Individual tubers from mature plants of cultivars Pentland Dell and Estima were harvested from experimental plots in two successive years and analysed for alpha-solanine, alpha-chaconine and total glycoalkaloid concentration (alpha-solanine and alpha-chaconine combined) using high-performance liquid chromatography. Mean tuber glycoalkaloid concentration per plant was stron gly affected by genotype and was much higher in plants of Pentland Dell (10 .0 and 16.3 mg per 100 g fresh weight in 1994 and 1995, respectively) than Estima (4.0 and 4.3 mg per 100 g fresh weight in 1994 and 1995, respectivel y). The variation between plants in mean tuber glycoalkaloid concentration, expressed as coefficient of variation, was similar for the two cultivars i n both years. Variation within plants was higher for cultivar Pentland Dell than Estima for both years but it was statistically significant only in 19 95. Tuber position within a plant had no effect on glycoalkaloid concentrat ions in tubers of similar size. An inverse relationship between total glyco alkaloid concentration and tuber fresh weight of individual tubers was foun d for both cultivars and small tubers of Pentland Dell (20-40 g fresh weigh t) exceeded the safety limit of 20 mg per 100 g fresh weight. The pattern o f glycoalkaloid accumulation differed between genotypes and appeared relate d to tuber growth. The implications of these results in terms of food safet y are discussed. (C), 1999 Society of Chemical Industry.