Abstract: The changes in carbohydrate enzyme activity and amyloplast membrane structure in potato tubers during storage were. studied by taking tile species. Kexin No.1 as example. The significant increase of level of total sugar and reducing sugar. Which caused the low. temperature sweetening and the colour darkening of fried-chip. was observed in the tubers stored at 4℃ The activities of amylase Starch-phosphorylase and invertase were different during storage at 4℃and 10℃.with the catalytic reaction much favoratable to the conversion from starch to reducing sugar at 4℃. Changes in integrity of amyloplast membrane were observed during storage .The injury to the amyloplast membrane was significant and the electrolyte leakage was higher in the tubers stored at 4℃

Key words: Potato Sweetening, Reducing sugar, Amyloplast