Polyphenol‑rich Fruit Peel Composite as a Potential Source of Antioxidants: Phytochemical Profile and In vitro Antioxidant Activity

Fruit peels constitute a large fraction of agro-industrial waste and are rich in bioactive phytochemicals which represent a potential source of antioxidants for food waste valorization and nutraceutical applications. In this study, banana, pineapple, orange, and watermelon were collected, peels separated, shade-dried, milled, and homogenized to form a composite powder (BPOW) in 1:1:1:1 mass ratio, which was extracted with methanol and analyzed following AOAC guidelines. Phytochemical screening confirmed the presence of alkaloids, phenols, tannins, flavonoids, and terpenoids, with quantitative analysis revealing high concentrations of alkaloids (366.28 mg/g), phenols (351.86 mg/g), tannins (178.30 mg/g), and terpenoids (215.61 mg/mL). Antioxidant activity was evaluated using DPPH, ABTS, and FRAP assays, yielding potent results with DPPH IC50 at 0.0060 µg/mL, ABTS IC50 at 16.942 µg/mL, and FRAP reducing power at 351.43 µg/mL Trolox equivalents. These findings highlight strong phytochemical density and antioxidant potency. In conclusion, the BPOW composite emerges as a potential source of antioxidants with potential applications in nutraceuticals, functional foods, and circular economy strategies aimed at reducing food waste and creating value added substances. Further in vivo assessment and human trials are recommended to establish in vivo activities.