Abstract:
To enhance the utilization potential of polyphenolic resources in persimmon peel waste, electron beam irradiation (EBI) coupled with conventional solvent extraction (CE) and subcritical extraction (SE) (EBI-CE, EBI-SE) were explored to investigate the effects of different extraction methods on polyphenol yields from persimmon peel. Based on this, the crude polyphenolic extracts from persimmon peel were purified, and the composition and in vitro antioxidant activity of the purified persimmon peel polyphenols were further analyzed. The results showed that the contents of persimmon peel polyphenols in SE and EBI-SE were 34.93 mg GAE/g DW and 31.93 mg GAE/g DW, respectively, which are 4.92 and 4.49 times that of CE. After purification, the content of persimmon peel polyphenols extracted by SE was 661.39 mg GAE/g DW and the antioxidant activity was also 4~5 times higher than that extracted by CE. 455 phenolic compounds, including 134 phenolic acids and 177 flavonoids were identified by UPLC-MS/MS. Gallic acid (5.73 mg/g DW) and quercetin (1.48 mg/g DW) contents in the polyphenols extracted by SE were extremely higher when compared to CE (0.02 mg/g DW and 0.30 mg/g DW, respectively). The EC
50 values of DPPH radical scavenging of these two monophenols were 35.83 μg/mL and 67.97 μg/mL, respectively. Multivariate statistical analysis indicated that quercetin and gallic acid are the key antioxidant monophenols in persimmon peel polyphenol extracts, with their concentrations exhibiting a positive correlation with total phenolic content. This study provides valuable insights for the valorization of persimmon peel waste as a sustainable source of natural antioxidants.