Potato tubers exposed to low temperature increase the reducing sugar content, that during the frying process causes the darkening of the product, losing its commercial value. The non-structural carbohydrates content of two potato cultivars (Perola and Atlantic) stored at two temperature conditions was evaluated. Tubers were produced at Embrapa Clima Temperado, Pelotas, (Brazil), in autumn and spring crops of 1999. Immediately after harvest, the tubers were divided in two lots, standardized as regards to the size and stored under room temperature (21±3ºC for autumn production; 24±2ºC for spring production) and cold storage (2±1ºC) for 40 days. Samples of two regions of the tubers (central and peripheral) were collected from the two storage conditions, at a ten-day interval, starting on the storage day of the tubers (time zero) during 40 days. In each sampling, the starch, sucrose, total soluble carbohydrates and reducing sugar content were evaluated. The starch content was not affected by storage temperature, while the other carbohydrates showed a rise in the cold stored tubers, mainly between 10 and 20 days. However, the changes due to low temperatures differed with genotype, crop season and region of the tuber.
Solanum tuberosum; reducing sugars; low temperature sweetening; storage
