Evaluation of physiochemical and antioxidant activity changes during fruit on-tree ripening for the potential values of unripe peaches

• The phytochemicals and antioxidant activity decreased rapidly during peach growth.
• Antioxidant activity was highly affected by hydroxycinnamate and (+)-catechin content.
• Dropped unripe peaches could be utilized as antioxidant resources.
• There are significant differences in antioxidant activity among peach cultivars.

The changes of physiochemicals associated with fruit quality, ascorbic acid and polyphenol content, and antioxidant properties during the last month on-tree ripening were investigated. Identification and quantification of ascorbic acid and polyphenols were performed using HPLC method. The antioxidant activities were evaluated by means of several in vitro assays, such as the β-carotene/linoleate model system, ABTS, DPPH and FRAP. The fruit growth resulted in statistically increased content of TSS and the reductions of the acidity (p < 0.05). Concurrently, the ascorbic acid and polyphenol content as well as antioxidant activities decreased (p < 0.05) dramatically over the ripening period. The results indicated that dropped unripe peaches are excellent sources of bioactive and antioxidant compounds, and can be explored for their health promoting values in food products. Furthermore, the antioxidant activity may be highly affected by hydroxycinnamates (chlorogenic and neo-chlorogenic acid) and flavan-3-ols contents.