LAUSR

BACKGROUND Blueberries are considered a "functional food" because they contain bioactive compounds such as flavonoids, phenolic acids, tannins, and anthocyanins. It is one of the most consumed berries in the world and is highly appreciated by consumers because of its unique taste and sensory properties. Fresh blueberries decay rapidly due to mould and water losses. To preserve qualitative and nutraceutical traits of fresh highbush blueberries during storage, the efficacy of 1 mM melatonin treatment was investigated at 5 °C for 3 weeks. RESULTS The results demonstrated that melatonin treatment reduced weight loss and delayed postharvest ripening. Compared to control, melatonin treatment induced an overproduction of polyphenols, flavonoids, anthocyanins, and ascorbic acid, consequently increasing antioxidant activity. The enzymatic antioxidant system was also affected by the treatment. An increase in the activity of catalase, superoxide dismutase, and ascorbate peroxidase was observed in treated fruit compared to that in control fruit. Enzymatic browning, controlled by assaying the content of malondialdehyde and hydrogen peroxide, polyphenol oxidase, guaiacol peroxidase, and lipoxygenase activities, appeared to slow down under melatonin treatment. CONCLUSION Melatonin coating is a valid tool to delay the perishability and qualitative decay of highbush blueberry fruit during cold storage. Furthermore, this treatment increases the production of secondary metabolites such as polyphenols, flavonoids, anthocyanins, and ascorbic acid, improving the nutraceutical traits of this fruit during storage. Melatonin treatment can be considered an environmentally sustainable, non-harmful-to-human-health alternative for postharvest preservation of highbush blueberry fruit. This article is protected by copyright. All rights reserved.