Abstract:

The effect of 10 mmol/L glycine betaine (GB) treatment on active oxygen metabolism in loquat fruits (Eriobotrya
japonica Lindl. cv. Jiefangzhong) during cold storage was investigated. The results showed that GB treatment effectively
reduced internal browning, inhibited the increase of electric conductivity and malonaldehyde (MDA) content, maintained the
low level of superoxide anion (O2－·) production and hydrogen peroxide (H2O2) content. Moreover, GB treatment enhanced
the activities of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) and inhibited the activities
of polyphenol oxidase (PPO) and peroxidase (POD). High levels of total phenols and total flavonoids were also observed in
GB-treated loquat fruits. These results suggest that GB treatment may maintain the balance of active oxygen metabolism and
reduce the lipid peroxidation and membrane damage, thereby reducing the chilling injury and extending the storage time of
cold-stored loquat fruits.

Key words: loquat, chilling injury, glycine betaine, active oxygen