Abstract
This study investigated the postharvest changes in the activities of invertase (EC ; 3. 2. 1. 26), sucrose synthase (SS ; EC 2. 4. 1. 13) and sucrose phosphate synthase (SPS ; EC 4. 4. 1. 14) in cucumber fruits (Cucumis sativus L. cv. Project X) stored at 13 and 25°C for 20 days to understand the changes in fruit quality in relation to firmness and color after harvest. The acid invertase activities in the soluble and cell-wall-bound fractions in the cucumber stored at 25°C were significantly higher than those stored at 13°C from days 4 to 16. The acid invertase activity was 30-35 times higher than the SS activity on day 8 of storage at 25°C. The SS and SPS activities in the cucumber fruits stored at 25°C showed the highest activity on day 8. Low-temperature storage was effective in decreasing invertase activity in both fractions, thereby suppressing sucrose degradation. Low-temperature storage at 13°C caused no chilling injury to the cucumber. It was effective in maintaining sucrose content, color and firmness of cucumber fruits.
