Glycoalkaloids in potatoes and potato crisps: The role of postharvest stress and food processing

Glycoalkaloids (GA) are substances in potatoes ( Solanum tuberosum L.) that can cause acute intoxication when ingested in excessive doses. However, data on GA in potatoes and potato products are limited. Consequently, this study aimed at characterizing GA contents of ten potato cultivars commonly used for further food processing in Europe and advancing the understanding of processing effects on GA levels. Potatoes were assessed in untreated and stressed conditions, including light-exposure, mechanical damage, and elevated temperatures. As expected, cultivar differences were found and among stress factors, light-exposure had the most pronounced effect on GA with an average increase of 83 %. For characterizing GA fate, potatoes were processed into potato crisps under standardized, industry-related conditions. It was hypothesized that processing leads to a significant GA reduction, which was confirmed with a decrease between 62 and 87 % from raw material to product based on fat-free dry matter. A key feature of the present study was the inclusion of a worst-case scenario by using stressed samples in the processing trials. It provides a first insight on the GA reduction potential of processing in relation to the initial GA content. It revealed that light-exposed tubers showed the lowest GA reduction during processing compared to the other treatments. This emphasizes the importance of selecting raw materials with low GA formation potential and avoiding stress factors in potato handling. In particular, light-exposed raw materials, recognizable by their green colour, should be sorted out to minimize GA contents in the product, regardless of greening intensity.