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During storage, winter jujube often experiences physiological disorders that can result in postharvest quality deterioration. To address this concern, a combination of 1% chitosan (CTS) and varying concentrations (0.02, 0.2, and 2 mg mL-1) of ε-polylysine (ε-PL) was applied. The findings indicated that the treatment involving the combination of 1% CTS with 0.2 mg mL-1ε-PL exhibited superior efficacy in preserving the hardness and titratable acid content of winter jujube. Additionally, the jujube fruits of this treatment exhibited a deceleration in the rise of decay incidence, red index, and weight loss rate. Simultaneously, the application of CTS combined with ε-PL treatment improved the levels of antioxidant enzyme activities (SOD, CAT, POD, and APX) and enhanced contents of antioxidant compounds (AsA and GSH). Moreover, the generation of reactive oxygen species (H2O2 and O2-.) was suppressed. Consequently, CTS combined with ε-PL treatment effectively enhanced postharvest quality and regulated antioxidant status of winter jujube. [ABSTRACT FROM AUTHOR]

Melatonin (MT), as a putative pleiotropic signal molecule, could participate in inducing postharvest disease resistance and inhibiting postharvest pathogen infection in fruit. In this study, we investigate the mechanism of induced resistance by MT treatment against Alternaria rot of jujube. The results showed that 2 and 20 μmol/L MT did not have direct antimicrobial activity, 200 μmol/L MT had little influence on antifungal activity against Alternaria alternata in vitro. MT significantly reduced the lesion area of fruit inoculated with A. alternata. MT decreased the relative electrolytic leakage, malondialdehyde content, hydrogen peroxide, and the rate of superoxide anion production, while enhanced the ascorbic acid and reduced glutathione contents. Furthermore, MT observably increased the defensive enzyme activities of superoxide dismutase, the catalase, ascorbate peroxidase, peroxidase. Accordingly, these results indicated that MT treatment increased the disease resistance of jujube fruit by regulating reactive oxygen species metabolism. Novelty impact statement: The results showed that MT treatment could inhibit the expansion of lesion diameter, reduce the decay rate of winter jujube, and reduce the accumulation of reactive oxygen species by activating the oxidase system, thus enhancing the resistance of winter Jujube fruit to Alternaria alternata infection by adjusting the ROS mechanism. [ABSTRACT FROM AUTHOR]