Effects of melatonin treatment on maintenance of the quality of fresh-cut pitaya fruit

Abstract

The present work investigated the effects of different concentrations of melatonin (0, 50, 100, and 200 μmol L-1) on the quality and antioxidant activity of fresh-cut pitaya (Hylocereus undatus) fruits. Results revealed that melatonin treatments significantly increased the firmness, total soluble solids, and titratable acidity of post-harvest fruits, and inhibited the rate of weight loss. When compared with the control treatment, the application of melatonin maintained higher contents of vitamin C and total phenolics in fresh-cut pitaya fruits during storage. Melatonin also decreased cell membrane electrolyte leakage and polyphenol oxidase activity, with 100 μmol L-1 melatonin treatment showing the best effects. In addition, 100 μmol L-1 melatonin significantly increased the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (APX), thus decreasing the accumulation of H2O2 and O2 during storage. Collectively, these findings indicate that melatonin treatment could contribute to delaying the ripening and senescence of fresh-cut pitaya fruits, and has potential application in the preservation of fresh-cut pitaya fruits during storage.