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Glycoalkaloid content of some superior potato ( Solanum tuberosum L) clones and commercial cultivars

2008; Taylor & Francis; Volume: 42; Issue: 5 Linguagem: Inglês

10.1080/03235400601164505

1477-2906

Geoffrey Kipkoech Kirui, Ashok Misra, O. M. Olanya, Mendel Friedman, R. El-Bedewy, Peter T. Ewell,

Phytase and its Applications

Abstract Glycoalkaloids are important metabolites in potato because of their toxic properties and potential harmful effects to humans. To validate a rapid assay to determine and quantify glycoalkaloid content and its distribution in potato tubers, we have characterized and quantified, by HPLC and by colorimetry with bromphenol blue, the glycoalkaloids in 15 potato cultivars and experimental clones grown in the tropical climate of Kenya. There was significant correlation of TGA by HPLC and colorimetry. Significant differences in glycoalkaloid content were detected among potato cultivars. The concentration of α-chaconine in the 15 cultivars ranged from 1.62 to 4.46 mg/100 g fresh weight (fwt), of α-solanine from 1.45 to 4.51 mg/100 g, and of solanidine from 1.58 to 5.21 mg/100 g. Total glycoalkaloid values (TGA, sum of the three compounds) for the 15 cultivars determined by HPLC ranged from 5.31 to 15.39 mg/100 g and the corresponding values determined by bromphenol blue colorimetry, from 3.51 to 17.48 mg/100 g. Dutch Robijn, a late blight susceptible cultivar under Kenyan conditions had the lowest level (3.51 mg/100 g) of total glycoalkaloids and Tigoni, a late blight resistant cultivar, had the highest amount (15.97 mg/100 g). In contrast to most previous studies, high levels of solanidine in tubers of tropical-climate adapted cultivars were recorded in our experiments. The dietary significance of a high amount of solanidine in the cultivars has not been previously reported and deserves further study.