Comparative Effect of Melatonin and 1-Methylcyclopropene Postharvest Applications for Extending ‘Hayward’ Kiwifruit Storage Life

Abstract

Kiwifruit, like many other fruits, is susceptible to dehydration, leading to texture changes and a loss of flavour during storage. Exposing kiwifruit to suboptimal temperatures can control these changes but can cause internal browning. Postharvest treatments with substances such as 1-methylcyclopropene (1-MCP) are some of the most successful commercial technologies in the conservation of fruits and vegetables. In recent years, there has been a growing interest among researchers in alternative technologies based in postharvest treatments with plant growth regulators. In this sense, melatonin (MT) has been shown to improve fruit quality, extending shelf life. The aim of this study was to compare these two different technologies applied at postharvest to evaluate the impact on kiwifruit quality. Optimal 1-MCP fumigations and MT solutions were assayed on ‘Hayward’ kiwifruit under similar conditions. Quality parameters were evaluated at 14-day intervals during 84 days of cold storage plus 5 days at 20 °C. The results showed that both treatments were similarly effective in maintaining quality parameters such as weight loss, respiration, firmness, and acidity. Although 1-MCP treatments delayed the evolution of kiwifruit colour and chlorophyll degradation as compared to MT, MT treatments controlled chilling injury better than 1-MCP. This effect was not related to a greater cell membrane integrity since fruit batches treated with 1-MCP were the ones that showed the lowest electrolyte leakage level. In conclusion, both treatments maintained fruit quality and delayed ripening in a similar way. In this sense, the results suggest that MT immersion treatments could act as efficient delaying senescence as fumigations with 1-MCP maintaining kiwifruit quality during refrigerated storage.