Effect of storage conditions on phenolic composition, vitamin C and antioxidant activity of 'Golden Delicious' and 'Red Delicious' apples

This study aimed to investigate the effects of 1-methylcyclopropene (1-MCP) treatment and storage atmosphere on phenolic composition, vitamin C, and antioxidant activity of 'Golden Delicious' (GD) and 'Red Delicious' (RD) apple cultivars during a 5-month refrigerated storage period. The results showed a significant decrease in vitamin C content in both cultivars (between 40 to 85%), regardless of the storage atmosphere, with a higher reduction observed for RD apples treated with 1-MCP. However, the impact on phenolic composition varied depending on the apple cultivar and storage conditions. In the case of RD apples, the flesh exhibited increased content of total hydroxycinnamic acids; total monomeric flavan-3-ols; total oligomeric flavan-3-ols, and total dihydrochalcones when treated with 1-MCP and stored under controlled atmosphere. On the other hand, GD apples experienced a smaller reduction in total phenolic compounds compared to storage under controlled atmosphere without 1-MCP treatment (32% vs. 57%). Both GD and RD apples showed a decrease in total phenolic compounds during storage compared to initial harvest (40% and 24% reduction for GD and RD with 1-MCP treatment, respectively). These changes in phenolic composition had a significative impact on the antioxidant activity observed in both the flesh (r = 0.721, p < 0.011), associated with changes in hydroxycinnamic acids and oligomeric flavan-3-ols, and the peel (r = 0.811, p < 0.0146), associated with changes in the sum of total anthocyanins and total flavonols. Overall, the study concluded that the health-promoting properties of apples are influenced by the specific storage conditions and the application of 1-MCP, with variations dependent on the apple cultivar. These results highlight the importance of tailored storage approaches to optimize the preservation of phenolic compounds and antioxidant activity in apples.