Tuesday, July 31, 2012
Grand Ballroom
The apple (Malus x domestica Borkh.) is one of the most popular fruit in the world and its consumption is highly recommended for a healthy diet. Polyphenolic compounds of apple fruit play an important role in physiologic functions related to human health. Different polyphenolics have varied biological activities including antioxidant activity. However, information about biological changes in polyphenol compounds during fruit ripening is still lacking. The objectives of this study were to investigate the qualitative and quantitative changes in polyphenolic compounds in apples and to evaluate the effect of 1-MCP treatment on the polyphenolic compounds during fruit ripening. To better understand fruit ripening and effect of 1-MCP on polyphenolic compounds, “Golden Delicious” apples harvested at pre-climacteric stage were allowed to naturally ripen, or ripening was inhibited by 1-MCP treatment (1.0 µL·L-1 for 16 h). Postharvest physiological indices including respiration, ethylene production, firmness and chlorophyll fluorescence were monitored for 47d. Six major polyphenolic groups with a total of 16 identified individual compounds were identified and quantified. Total antioxidant capacity, total phenolic, flavonols and dihydrochalcones were not significantly changed. Total hydroxycinamics and procyanidin were significantly decreased. No significant change in quercetin and most of its conjugates (quercetin galactoside, rhamnoside, arabinoside and xyloside) were found, except for quercetin-3-glucoside which was increased by 1-MCP treatment at a late stage. Significant decrease in chlorgenic acid, phloridzin, epicatechin, and procyanidin B2 were found during fruit ripening and were also decreased by 1-MCP treatment. p-Cumarylquinic acid level decreased in response to fruit ripening but was maintained by 1-MCP treatment. Neo-chlorgenic acid was higher in 1-MCP treated fruit than control. The results obtained in this study demonstrated that the complex changes in polyphenolic compounds in apples during ripening. 1-MCP treatment may have limited effect on these changes. This research provided further understanding about polyphenolic compounds in relation to fruit ripening and regulation, which will be helpful for postharvest management on enhancement of health-promoting physiological functions in apple fruit.