Effect of Intermittent Treatment with Different Concentrations of Ozone on Preservation and Antioxidant System of Kiwifruit

In order to study the effect of intermittent ozone treatment on the storage quality and preservation of kiwifruit, ‘Hayward’ kiwifruit were fumigated with different concentrations (0, 21.4, 42.8 and 64.2 mg/m³) of ozone once every seven days during storage at (0.0 ± 0.5) ℃. Quality indexes and the antioxidant enzyme activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) were measured regularly during storage. The results showed that compared with the control group, ozone treatment at all concentrations effectively reduced fruit mass loss rate, soft fruit rate and decay rate, inhibited the increase of total soluble solid (TSS) and malondialdehyde (MDA) contents, delayed the decrease of titratable acid (TA) content and fruit hardness, and maintained higher vitamin C (VC), total phenol and flavonoid contents. The preservative effect of ozone at 42.8 mg/m³ was better than those at 21.4 and 64.2 mg/m³ concentrations. After 140-day storage, the hardness and VC content in the 42.8 mg/m³ treatment group were 76.92% and 43.10% higher than those in the control group, respectively. The peak values of catalase (CAT) and peroxidase (POD) activity were 36.53% and 89.31% higher than those of the control group, respectively. Ozone treatment also effectively controlled the soft fruit rate and decay rate of kiwifruit during the shelf-life period. On the 9th day, the decay rate of the 42.8 mg/m³ treatment group was 16.67%, which was 63.77% lower than that of the control group. It is concluded that intermittent ozone treatment at a concentration of 42.8 mg/m³ can effectively slow down the senescence process and improve the storage quality and nutritional value of kiwifruit.