Abstract
To evaluate the changes of total phenolic content and antioxidant capacities of five peach cultivars, this work measured them separately in extractable polyphenols and non-extractable polyphenols during the last month of ripening. Total phenolic content was detected using the Folin-Ciocalteau reagent, while total antioxidant activity was detected by DPPH and FRAP assay. In addition, the contribution of extractable polyphenols and non-extractable polyphenols to the total antioxidant activity of peaches was investigated. It is noted that ripening caused a decrease of total phenolic content associated to extractable polyphenols and non-extractable polyphenols by 45.1%–74.6%, 20.7%–41.7%, respectively. Additionally, total antioxidant activity decreased over the ripening period with a high correlation with total phenolic content. Extractable polyphenols contributed more than 50% to the total antioxidant activity, while the non-extractable antioxidants contributed around 31.3%–45.7% (DPPH) or 12.6%–25.4% (FRAP), which suggests that the antioxidant properties of peaches may be undervalued in previous researches.
