Comparative Evaluation of in vitro Antioxidant Activities and High‑Performance Liquid Chromatography Fingerprinting of Fruit Peels Collected from Food Processing Industry Wastes

Background: An enormous quantity of fruit peel is obtained from food processing industry as leftover materials which cause environmental pollution if not used judiciously. Objective: The present study was focused to explore antioxidant activities and detect bioactive compounds of three different fruit peel wastes (orange, mango, and pomegranate) collected from fruit processing centers. Materials and Methods: Peel extracts were primarily investigated for total phenolic and total flavonoid content (TFC) in three different solvent systems, namely aqueous–methanolic (20:80, v/v), ethanolic, and aqueous. These were examined for in vitro antioxidant potential by 2,2‑diphenyl‑1‑picrylhydrazyl hydrate (DPPH) and ferric reducing antioxidant power (FRAP) test. Peel waste extracts were further characterized by high‑performance liquid chromatography. Results: Pomegranate peel (PP) wastes exhibited significantly (P < 0.01) high concentration of total phenolic content (TPC) and TFC followed by mango peel (MP) wastes and orange peel (OP) wastes. DPPH and FRAP tests revealed significantly (P < 0.01) high antioxidant activity in aqueous–methanolic and aqueous extract of PP. The degree of antioxidant activities in each type of solvent was in the order of PP >MP >OP. Pearson’s correlation coefficient analysis revealed a strong association between antioxidant activity and TPC. High concentration of gallic acid, salicylic acid, chlorogenic acid, rutin, and catechin was observed in aqueous–methanolic (20:80, v/v) extracts of PP, and these might be the reason behind the higher antioxidant activities of PP. Conclusion: Results of this study clearly suggest that PP waste contains strong antioxidant molecules and might be used as additive in commercial feed to ameliorate oxidative stress in animals.