Effect of abscisic acid (ABA) and chitosan/nano-silica/sodium alginate composite film on the color development and quality of postharvest Chinese winter jujube (Zizyphus jujuba Mill. cv. Dongzao)

The color change of the jujube fruit after harvest is used as a quality indicator. The effects of abscisic acid (ABA) and a chitosan/nano-silica/ sodium alginate composite film on the color development and qualitative properties of harvested jujube in cold storage were investigated. The results indicate that a composite film could prolong the shelf life of post-harvested winter jujube for approximately 1 month, while the ABA treatment induced ripening and reduced the quality. A significant positive correlation between the a*/b* values, water loss and the malondialdehyde (MDA) content was found for fruits in cold storage. In comparison with the control and ABA-treated fruit, superoxide dismutase (SOD), polyphenol oxidase (PPO) and peroxidase (POD) activities were lower than those in a composite film-treated fruit. In addition, the dihydroflavonol-4-reductase (DFR) is the primary gene that regulates the expression of anthocyanin.