Postharvest melatonin treatment reduces chilling injury in sapota fruit

BACKGROUND Sapota is a popular tropical fruit characterized by a very short postharvest life. Low-temperature storage prolongs postharvest life of sapota fruit, but chilling injury symptoms can develop if the storage temperature is less than 14 degrees C. There have been no reports on the effects of postharvest melatonin application on the development of chilling injury in sapota fruit during cold storage. The objective of this study was to investigate the effects of different concentrations of postharvest melatonin application (0, 30, 60 and 90 mu mol L-1) during cold storage (8 degrees C) for up to 30 days with an additional 1-day shelf life at ambient temperature. RESULTS All melatonin treatments reduced chilling injury symptoms, reduced electrolyte leakage, malondialdehyde (MDA) content, H2O2 and superoxide anion (O-2(-)), and increased proline content and the activity of superoxide dismutase (SOD), catalase (CAT) and gamma-aminobutyric acid (GABA), and reduced the activities of phospholipase D (PLD) and lipoxygenase (LOX) compared to the control. CONCLUSION Postharvest melatonin treatment could be a useful strategy for reducing chilling injury during cold storage and transport of sapota fruit. The results indicate that melatonin reduces chilling injury of sapota fruit through maintaining membrane integrity, SOD and CAT activities, and reducing PLD and LOX activities. (c) 2019 Society of Chemical Industry