Effects of Ozone Treatment on Reactive Oxygen Species Metabolism and Storage Quality of Flat Jujubes (Ziziphus jujuba Mill. cv. Panzao)

Moderate ozone exposure has emerged as a sustainable strategy to enhance postharvest quality in perishable fruits. This study investigated the effects of ozone treatment (2.14–19.27 mg/m3) on flat jujube during 70-day cold storage (0 °C). Results demonstrated that following 70 days of storage, the ideal ozone concentration (10.72 mg/m3, T2) led to a decrease in weight loss of 44.8% and preserved 66.7% firmness when compared to the control check (CK) group. The T2 group suppressed the respiration rate and delayed declines in total soluble solids (TSSs) and titratable acid (TA). Mechanistically, ozone enhances enzymatic activity, with T2 elevating superoxide dismutase (SOD), catalase (CAT), and peroxiredoxin (POD) activities while reducing the accumulation of reactive oxygen species (ROS) and lipid peroxidation. Total phenolics and flavonoids in T2 remained 42% and 52% higher than CK at 56 days, correlating with elevated 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) scavenging activities. Browning inhibition (25% lower than the CK group) is linked to suppressed polyphenol oxidase (PPO) activity and phenolic oxidation. Principal component analysis (PCA) confirmed ozone’s efficacy in delaying senescence via ROS homeostasis and antioxidant synergy. These findings establish moderate ozone as a novel, eco-friendly intervention to extend jujubes’ shelf life, emphasizing its dual role in quality preservation and oxidative stress regulation.