Changes in nutritional components and glycoalkaloid levels of stored potatoes

In this research, normal, mechanical injured and green potatoes belonging to cv. Marfona and Granola were used to determine changes in glycoalkaloid (GA) levels and nutritional components during the storage. The potatoes were kept in normal and refrigerated conditions using two different illumination types (dark and light). GA content and general nutrient components were determined at the beginning and at the end of 3th and 6th months of the storage. At the end of 6 months, GA content was also measured in the sprouts appeared in potatoes. Sensory properties of the potatoes were determined on french fried, boiled and baked potatoes. During the storage period, it was observed that dry matter and compositional components appeared to increase relatively as a result of moisture loss, while color was getting pale and GA level was getting high. It was found that Marfona was more sensitive to cold, had lighter color and lower nutrition components than that of Granola. It was determined that normal potatoes had the lowest changes in terms of the investigated parameters while the mechanical injured potatoes had the highest ones. In terms of GA, green potatoes had the highest level of GA. Although the highest changes occured in potato stored in normal light store, the lowest changes appeared in potatoes stored in dark and refrigerated stores. During storage period, vitamin C contents of the all groups were decreased. The decreases were higher in lighted-refrigerated and dark- refrigerated storage groups than that of the normal-light storage and normal-dark storage samples. It was observed that there was no sprout formation in any of the samples kept in refrigerator (dark-light). The potatoes kept in normal lighted storage had higher total GA contents than that of the normal dark storage samples, and GA content of the sprouts was higher than that of tubers. Alfa-chaconine contents of both tuber and sprouts were higher than cc-solanine contents. In conclusion, it can be suggested that undamaged, ungreened, normal potatoes should be stored in dark at 5-8°C to prevent discoloration, sprouting, the changes of nutritional values and GA levels. 2002, 118 pages Keywords: potato, Marfona, Granola, storage, GA, a-chaconine, a -solanine, HPLC