Alleviation of postharvest rib-edge darkening and chilling injury of carambola fruit by brassinolide under low temperature storage

Carambola fruit produced in the tropical and subtropical region could easily suffer the postharvest loss in low temperature storage and cold chain logistics owing to the hazard of chilling injury (CI). Here, the effects of brassinolide (BR) on phenolic metabolism, rib-edge darkening and CI of carambola fruit were studied. The present results showed that BR treatment effectively delayed the CI and weight loss, maintained peel color and flesh firmness, and inhibited the increases of electrolyte leakage, malondialdehyde and reactive oxygen species production, induced total phenols and proline accumulation. Moreover, BR treatment raised the activities of antioxidant enzymes and higher content of individual phenolic compounds, inhibited membrane lipid peroxidation and safeguard cellular membrane integrity. This study for the first time demonstrated that BR could alleviate CI in carambola fruit during low temperature storage and cold chain circulation.