Effect of storage temperature on chilling injury and activity of antioxidant enzymes in carambola “Arkin” fruit

Abstract

Carambola fruit at yellow–green stage were stored at 2, 5, 10, 15, and 20°C for 21 days then transferred to 20°C for 7 days. Fruit at 20°C reached the overripe associated with soft flesh and surface blemishes. Fruit at 15°C ripened due to slight differences in maturity. Fruit at 2 or 10°C ripened slowly, however, speed up once transferred to 20°C along with chilling injury and lost shelf life. Fruit at 5°C ripened slowly even after transfer to 20°C, and maintained the color and firm texture. Activities of peroxidase, superoxide dismutase, and catalase increased during storage at 20°C, but had lowest values at 5°C. Activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase increased in fruit at 5°C. The results implied 5°C storage extended shelf life and enhanced ascorbate–glutathione cycle which protected fruit from damage. Practical applications Carambolas stored at 5°C did not ripen and their quality was kept after transfer to 20°C. Carambolas stored at 2°C then to 20°C ripened but showed physiological disorder. Chilling storage specially at 5°C enhanced the ascorbate–glutathione cycle. At suitable ripening condition, scavenge of reactive oxygen species (ROS) in carambola fruit was more effective. As a result, these fruit had a high scavenging capacity for ROS, which causes chilling damage to the fruit and affects the process of fruit ripening. Therefore, we suggest that storing the carambola at 5°C results in prolonged shelf life and improved visual quality and appearance, and therefore, greater commercial acceptability.