Melatonin maintains the storage quality of fresh-cut Chinese water chestnuts by regulating phenolic and reactive oxygen species metabolism

Abstract

Fresh-cut Chinese water chestnuts (CWCs) are prone to quality deterioration during storage, which does not meet consumer demand. In this study, the effect of exogenous melatonin (5 mmol L-1) on the quality and potential mechanisms in fresh-cut CWC was investigated. The results showed that melatonin treatment alleviated the cut-surface discoloration of CWCs. Not only did this treatment significantly slow down the increase in browning degree and yellowness (b*) as well as the decrease in lightness (L*), but it also significantly delayed the loss of weight and total soluble solids. Further investigations indicated that melatonin-treated fresh-cut CWCs exhibited significantly lower total phenolics and soluble quinones and suppressed the activities of phenylalanine ammonia-lyase, polyphenol oxidase, and peroxidase. Meanwhile, when fresh-cut CWCs were treated with melatonin, the total flavonoid concentration was significantly decreased compared to the control. Additionally, melatonin significantly inhibited the accumulation of H2O2 and malondialdehyde as well as enhanced the activities of superoxide dismutase and catalase by promoting the production of O2- . In summary, melatonin treatment may delay the surface discoloration of fresh-cut CWCs by inhibiting phenolic compound metabolism and improving antioxidant capacity, thereby effectively maintaining the quality and prolonging the shelf life of fresh-cut CWCs.