Abstract: In this study, xuanhua-milk,, grapes were soaked in chitosan coating solution before harvest, and stored at 0 ℃ for 100 d. The respiration intensity, ethylene production, total phenolics content, polyphenol oxidase activity, chlorophyll content, titratable acidity, soluble solids content, weight loss, decay rate and browning index of the grapes were investigated during storage. The results showed that the coating treatment had good effect on inhibiting the respiration intensity, ethylene production and polyphenol oxidase activity. Compared with untreated grape, respiration intensity of grape treated with preharvest-coating were reduced by 42.5% at 50 day and 53.8% at 75 day, respectively. After storage for 100 days, decay rate was 5.2% in coating-treated group, and 92% in the control group. Browning index was reduced by 81.6% at 75 day compared with untreated grape. Meanwhile, higher soluble solids, titratable acid, chlorophyll and total phenolics content remained in grapes of coating-treated group than in the control. Furthermore, preharvest coating increased the shelf life and maintained the sensory quality of grape fruits, resulting in a 2-fold prolongation of shelf-life compared with untreated grape.

Key words: grape, preharvest-coating, storage physiology, storage quality