Abstract: In order to explore the effect and underlying mechanism of exogenous p-coumaric acid (p-CA) on chilling injury (CI) in postharvest peach fruit, ‘Shahong’ peach fruit were immersed in 0, 0.5 and 1 mmol/L p-CA to investigate the effect of p-CA on CI index and malondialdehyde (MDA) content during subsequent storage at 4 ℃. It turned out that 0.5 mmol/L p-CA was selected as the optimal treatment concentration. In this case, we further studied the effect of p-CA treatment on phenylpropanoid metabolism and antioxidant capacity in postharvest peach fruit. The results showed that p-CA treatment significantly delayed the development of CI and the generation of MDA in peach fruit. p-CA treatment stimulated the activity of shikimate dehydrogenase, phenylalanine ammonia lyase, cinnamate-4-hydroxylase and 4-coumarate coenzyme A ligase, but inhibited polyphenol oxidase and peroxidase activities, which contributed to higher total phenolic content in peach fruit and thus enhanced 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radical scavenging capacity. This study indicated that the alleviating effect of p-CA on CI was associated with its ability to regulate phenylpropanoid metabolism and antioxidant capacity in peach fruit.

Key words: p-coumaric, peach fruit, chilling injury, phenylpropanoid metabolism, antioxidant capacity