Exogenous Melatonin Treatment Delays Senescence of Guava Fruit by Modulating Antioxidant Activities

Abstract

Guava (Psidium guajava L.) is an important subtropical fruit, demanded for its unique flavour and rich nutritional value. The fruit is highly perishable and has a limited postharvest life of 2–3 days at ambient conditions. The present study aimed to investigate the effect of postharvest melatonin treatments (200, 400, 600 and 800 µM) on ripening and senescence of guava during storage under ambient conditions (25 ± 1 °C). It was observed that melatonin treatment delayed the increase in soluble solids content and minimized loss of chlorophyll, total phenols and ascorbic acid. Lower malondialdehyde content was recorded in melatonin treated fruits, while showing increased antioxidant capacity and reduced oxidative damage to fruit. Melatonin treatment significantly enhanced the activities of catalase, superoxide dismutase, and delayed increase in polyphenol oxidase and peroxidase enzyme activities. These results showed that exogenous melatonin treatment can maintain desirable quality attributes of guava fruit by preserving various physico-chemical and antioxidant parameters of fruit. © The author(s), exclusively licensed to Springer-Verlag GmbH Germany, a part of Springer Nature 2025.