Postharvest melatonin treatment reduces chilling injury and enhances antioxidant capacity of tomato fruit during cold storage

Abstract

 In this study, tomato fruit was treated with 50, 100 or 200 µM melatonin and then stored at 5°C for 28 days to investigate the effect of melatonin treatment on chilling injury, nutritional quality and changes in the antioxidant system. Tomato fruit developed chilling injury, manifested as surface pitting and irregular red color development during storage. These chilling injury symptoms, ion leakage and malondialdehyde content were significantly reduced, and proline and carotenoids contents were significantly increased by melatonin treatment. Meanwhile, melatonin substantially reduced O2- production rate and H2O2 content, which result from significantly higher activities of superoxide dismutase, catalase, and peroxidase than control during the storage. These results suggest that melatonin treatment can effectively enhance chilling tolerance and reduce chilling injury. The reduction in chilling injury by melatonin may be associated with enhanced enzymatic and non-enzymatic antioxidants, in favor of membrane integrity and thus low cellular and tissue damage.