Changes in ascorbic acid content and ascorbate metabolism-related enzyme activities during storage in cucumber (Cucumis sativus L.) and balsam pear (Momordica charantia L.)

Investigating the trends of ascorbic acid reduction in fruits at low temperature storage would importantly elucidate the reasons for occurrence of chilling injury (CI) physiological disorder. Cucurbita fruits stored at 5,10, and 20°C were analyzed for ascorbic acid (ASA) content, and activities of ascorbate oxidase (AOX), ascorbate peroxidase (APX), and monodehydro ascorbate reductase (MDR). CI was observed in cucumber fruits at 5°C, as well as in balsam pear fruits at 5 and 10°C. The cucumber fruits at 10°C also developed core browning. ASA content decreased in cucumbers but remained constant in balsam pears when the fruits were stored at 5 and 10°C. However, it quickly declined in balsam pear fruits stored at 20°C.[...]