In vitro antioxidant activity and punicalagin content quantification of pomegranate peel obtained as agro-waste after juice extraction

Abstract

The aim of current investigation was to assess total phenolics (TPC), total flavonoids (TFC) and punicalagin content (PC) of pomegranate peel extracts (PPEs) for its utilization as functional ingredient in food processing industry. Antioxidant rich fractions were extracted from Punica granatum L. (pomegranate) peel using methanol, ethanol and ethyl acetate. Furthermore, the extracts were characterized to assess their antioxidant potential using in vitro DPPH assay model. Methanolic extracts inhibited 78.23% free radicals; however ethyl acetate extracts showed least antioxidant activity. Maximum phenolic and flavonoid contents were extracted in methanolic extracts that were documented as 289.40 ± 12.75 mg/g GAE (Gallic acid equivalents) and 58.63±3.41 mg/g RE (Rutin equivalents), respectively, whereas punicalagin (110.00 ± 5.10 mg/g) was the major ellagitannin detected and quantified. Significant correlation (r = 0.981, 0.958; N = 3) was observed between total phenolics, total flavonoids and antioxidant activity of respective extracts. Correlation analysis (r = 0.982; N = 3) suggested that punicalagin might be the reason for potent antioxidant activity of PPEs. Conclusively, the outcomes of this study could serve as baseline information for fruits and vegetable processors in formulation of nutraceutical and therapeutic designer foods.