Antioxidant activity determines on-tree maturation in 'Golden Smootheé apples

Abstract

BACKGROUND: Harvest date clearly determines the postharvest storage behaviour and sensitivity of fruit to physiological disorders. Generally fruit are picked following theirmaturity indexes but often these indexes poorly represent the physiological state of the fruit. With this in mind, thiswork aimed to determine a biochemical marker capable of predicting on-tree maturation in 'Golden Smootheé apples. Changes in the non-enzymatic and in enzymatic antioxidant potential of fruit were assessed for different harvest dates. RESULTS: Significant differences in antioxidant levels, especially ascorbate and catalase, were found. These changes were related to climatic variations, especially relating to temperature, that appeared to determine the capability of the fruit to produce ethylene. Fruit exposed to higher temperatureproduced less ethylene andexhibited a significant delay inthe induction of their climacteric. In both seasons, changes in quality parameters during on-tree ripening were not related to the capability of the fruit to produce ethylene, but rather to endogenous levels of antioxidants, especially catalase and ascorbate, at the earliest picking date. CONCLUSION:We hypothesize that ascorbate and antioxidant activity play a role in changes inmaturity patterns exhibited by apples in orchards. Both parameters appear to be interestingmarkers to follow these changes. © 2009 Society of Chemical Industry.