Changes in invertase activities and reducing sugar content in sweetpotato stored at different temperatures

Cured sweetpotato roots were stored at different temperatures (4.5, 15.6, a nd 24 degrees C) for 7 weeks and assayed for invertase activities and reduc ing sugar levels during two separate years. Invertase activities and reduci ng sugar concentration significantly increased in the roots kept at low tem perature. Of the three types of invertases assayed, acid invertase specific activity was the highest. Acid invertase was the most influential in deter mining reducing sugar levels in stored sweetpotato. Cultivar differences we re found in invertase specific activities and reducing sugar concentration. Reducing sugar content was highly-correlated to acid and total invertase a ctivity, regardless of cultivar.