Abstract:

This study aimed to examine the effect of 60Co γ-irradiation on postharvest physiological and storage quality
of Pleurotus ostreatus. Pleurotus ostreatu was treated with different doses of 60Co γ-irradiation (0.5, 0.8, 1.0, 1.3, 1.6 and
2.0 kGy, respectively), and the changing patterns of the physiological and biochemical parameters and the storage quality
during storage at 6 ℃ were observed. The results showed that the quality of Pleurotus ostreatus was improved with doses of
60Co γ-irradiation in the range of 0.5–1.0 kGy, and the freshness was 0.5 by 1.0 kGy irradiation at the end of storage, which
was best preserved under this condition. The 60Co γ-irradiation at optimal doses of 0.5–1.0 kGy could effectively inhibit
the browning and polyphenol oxidase (PPO) activity of Pleurotus ostreatus, and the browning degree (BD) was positively
related with PPO activity by statistical analysis as shown in the following formula: BD = 0.018 3 PPO activity − 0.152 7
(R2 = 0.753 9，P ＜ 0.05). Moreover, the 60Co γ-irradiation could also suppress the decreases in the activities of superoxide
dismutase (SOD), catalase (CAT) and peroxidase (POD), and decrease the accumulation of malondialdehyde (MDA)
and superoxide anion (O2
－·) and the weight loss. It is summarized that 60Co γ-irradiation at 0.5–1.0 kGy can reduce the
browning of Pleurotus ostreatus, delay the senescence, maintain its storage quality and prolong its shelf-life to 10–12 d.

Key words: 60Co γ-irradiation, Pleurotus ostreatus, postharvest physiology, storage quality