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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]

Abstract: The effect of ultraviolet irradiation combined with chitosan coating on fresh jujube under ambient temperature was investigated. In the first period, the jujubes were irradiated for 4, 6, 8, 10 min at 253.7 nm ultraviolet, or coated with 1%, 1.5%, 2% and 2.5% of chitosan, respectively. In the second period, the jujubes were firstly irradiated 6 min, and then coated with 1.5% of chitosan. The result showed that combined treatment could reduce decay incidence of jujubes and restrain increase of respiration rate, weight loss, malonaldehyde content and electrolyte leakage of jujubes. Furthermore, the activities of superoxide dismutase, peroxidase, and catalase were maintained at higher level, and the decrease of ascorbic acid and chlorophyll was restricted. The present data indicated that treating post-harvest jujubes with ultraviolet irradiation combined with chitosan coating was an effective method, and might be considered in commercial application for preservation of postharvest fruit. [Copyright &y& Elsevier]

Background To effectively extend the shelf life of fresh jujube, carbon monoxide (CO), as a small molecular gas, was applied to fumigate fresh jujube. The quality and antioxidant activity of jujubes fumigated with carbon monoxide at concentrations of 0 (control), 5, 10, 20 and 40 µmol L−1 for 1 h under ambient temperature were investigated. Results The jujube fumigated with 10 µmol L−1 CO showed the best preserving effect amongst all samples. At 30 days, the decay incidence of jujube fumigated with 10 µmol L−1 CO is only two-thirds of that of control sample; its red index and weight loss rate were 22.8% and 19.4% lower, and its firmness, soluble solids content (SSC) and acidity were 18.7%, 5.4% and 12.2% higher than that of control samples, respectively. Its vitamin C and total flavonoid contents were also the highest. However, no significant difference in total polyphenol content was found. The jujubes treated with 10 µmol L−1 CO exhibited the highest antioxidant activity in terms of reducing power and 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl radical scavenging activity. However, the jujubes fumigated with 40 µmol L−1 CO showed inferior characteristics compared with the control sample. Conclusion Fumigating jujubes with proper concentration of CO probably is a potential novel method for post-harvest jujube preservation in the future. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: The effect of 1% chitosan film with 0.04% nano-silicon dioxide on the qualitative properties of harvested jujube under ambient temperature was investigated. After 32d, the red index, decay incidence, weight loss, and respiration rate of the coated jujubes were lower compared with those of the control. The lower phenylalnine ammonialyase activity and higher activities of scavenger antioxidant enzymes (i.e., superoxide dismutase, peroxidase, and catalase) of the coated jujubes can be attributed to the compound coating. Increased malonaldehyde in the coated jujubes was restrained. Composite coating had shown to be superior in preserving total flavonoid than chitosan coating alone. But no differences were observed in terms of vitamin C loss and total polyphenol content between composite coating and control. Coating jujubes with chitosan+nano-silicon dioxide will be a promising alternative if nano-silicon dioxide is allowed for food use. [Copyright &y& Elsevier]