Abstract:
We aimed to investigate the effect of methyl jasmonate (MeJ) treatment on the antioxidant system and browning of post-harvest jujube (Zizyphus jujuba Mill.) fruit during cold storage. Fruits were treated with 50, 100, and 200 μmol/L MeJ for 24 h. Control fruits and MeJ-treated fruits were sealed in air and stored at 2±0.5 ℃. Fruit firmness, decay index, respiration rate, superoxide anion production rate,and the content levels of hydrogen peroxide, malonaldehyde (MDA), ascorbic acid (AsA), glutathione (GSH), and total phenols (TP), as well as the activity levels of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO) were evaluated for all groups. Results showed that, during cold storage, MeJ treatments significantly delayed the decrease of fruit firmness; inhibited the respiration rate and decay index; decreased the accumulation of superoxide anion, hydrogen peroxide, and MDA; maintained higher activities of SOD, CAT, and POD; maintained levels of AsA and GSH; lowered the level of PPO activity; and increased TP content. Principal component analysis showed that the decay index, superoxide anion production rate, hydrogen peroxide content, MDA content, and PPO activity were the main factors that influenced the efficacy of MeJ. Furthermore, the 100 μmol/L MeJ treatment was most effective in maintaining fruit quality, enhancing antioxidant capacity, and inhibiting browning during cold storage.
