Investigation on the phenolic composition, related oxidation and antioxidant activity of thinned peach dried by different methods

The effects of five drying treatments on the polyphenol composition and antioxidant activity of thinned peach, as well as the enzymatic oxidation-related interactions of chlorogenic acid (CA), neochlorogenic acid (NCA) and catechin (CT) were studied. NCA, CA and CT were the dominant polyphenols in the thinned peach, and polyphenol oxidation was the main factor that affected the changes of polyphenol profiles in thinned peach treated by natural drying (ND) and hot air drying (HAD). Specifically, CT was more susceptible to oxidation than CA and NCA in polyphenol oxidase -catalysed oxidation. Furthermore, there was competitive inhibition between CA, NCA and CT in the polyphenol enzymatic oxidation process. In addition, the antioxidant activity of the thinned peach extracts was significantly affected by polyphenol oxidation and their concentrations, and the antioxidant activity of NCA, CA and CT were higher than that of the polyphenol derivatives formed after enzymatic oxidation. This work illustrated that freeze drying (FD) and HAD at 50 degrees C are suitable for making thinned peach, with retained polyphenol contents and antioxidant activity.