Effect of light and temperature on the formation of glycoalkaloids in potato tubers

This study was designed to determine the influence of two light sources and temperature on the total glycoalkaloid (TGA) content of potato tubers cultivated in Brazil. Tubers of cv Monaliza were exposed during 14 days to the following conditions: (1) indirect sunlight, (2) fluorescent light, (3) storage in darkness under refrigeration, and (4) storage in darkness under room temperature. The glycoalkaloids alpha-solanine and alpha-chaconine were determined using a reversed phase C18 HPLC column with a photodiode array detector. Exposure of potato tubers to fluorescent light resulted in the highest TGA levels. Smaller tubers presented the highest TGA concentrations, irrespective of the light source and temperature. Although the TGA levels at the end of the experiments were higher than the initial content, a steady increase of TGA concentration was observed only in tubers exposed to fluorescent light. The levels of TGA found in the analysed potato samples were below 200 mg kg(-1), value that has been considered to be safe for human consumption. (c) 2006 Elsevier Ltd. All rights reserved.