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

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.