Effect of natamycin treatment on physiological metabolism and quality of postharvest sweet cherry

In order to explore the effects of natamycin combined with Vc treatment on the physiological metabolism and quality of postharvest sweet cherry and its mechanism, fresh sweet cherries were dipped in 10 mg/L natamycin solution, 100 mg/L Vc solution, as well as 10 mg/L natamycin + 100 mg/L Vc solution for 10 min, respectively, and then transferred to 5℃ condition for storage. During the period of storage, respiration rate and the activities of some disease resistance-related enzyme such as polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL) were measured. Meanwhile, fruit color, firmness, Vc and phenolic substances content as well as decay rate of quality index were analyzed. The results indicated that natamycin treatments with/without Vc extended the storage period of up to 10 d or more. In particular, treatment with 10 mg/L natamycin + 100 mg/L Vc significantly increased PPO, POD, PAL activity and the polyphenol content, reduced fruit respiration rate and decay rate, and maintained a high Vc content and firmness. The individual natamycin treatment also had a certain role in regulating metabolism and preservation, while the sole Vc treatment had no obvious effects on disease control. These data suggest that natamycin combined with Vc treatment may be used as natural preservatives in the practical application of sweet cherry storage and transportation.