Abstract: To evaluate the effect of exogenous melatonin on the quality preservation of strawberry during storage, this work studied the influence of melatonin at different concentrations (100, 300 and 500 μmol/L) on the decay and nutritional quality of strawberry during postharvest storage at 20 ℃. The results showed that melatonin at all concentrations could inhibit fruit decay, delay the decrease of firmness and total soluble solids, and maintain ascorbic acid (ASA) with 300 μmol/L being the most effective concentration. In addition, 300 μmol/L melatonin had a significantly positive effect on the antioxidant capacity of strawberry during storage for up to 12 days at low temperature (4 ℃). It could also slow down the accumulation of malondialdehyde (MDA) and hydrogen peroxide, inhibit superoxide anion radical production, and maintain glutathione (GSH), ascorbic acid content and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX). Moreover, the scavenging capacities of strawberry on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical and hydroxyl radicals were significantly increased after treatment with melatonin. Therefore, melatonin treatment proved to be effective in extending the storage life and maintaining the quality of strawberry.

Key words: strawberry; melatonin; quality; reactive oxygen species metabolism