Pomegranate peel extract as a bioactive inhibitor of polyphenol oxidase: a green alternative for extending fresh-cut produce preservation.

Abstract

Natural plant extracts, particularly those rich in flavanols, are promising alternatives to prevent enzymatic browning in fresh-cut fruits and vegetables. Pomegranate peel, an abundant agro-industrial byproduct, has been recognized as a potential source of bioactive compounds with antioxidant and enzyme inhibitory activities. This study investigates the inhibitory effects of a phenolic extract from the peel of Hicaz variety pomegranate on polyphenol oxidase (PPO) and its impact on the quality attributes of fresh-cut produce. The extract, obtained by ultrasound-assisted extraction with a yield of 33.55%, was analyzed using liquid chromatography-tandem mass spectrometry, revealing seven major phenolic compounds. Molecular docking studies confirmed strong binding interactions with PPOs. Enzyme inhibition assays demonstrated IC₅₀ values of 0.86, 0.95 and 0.73 mg mL-1 for potato, mushroom and apple PPOs, respectively, indicating a mixed-type inhibition mechanism. Fresh-cut samples treated with 2 mg mL-1 extract and stored at 4 °C showed improved preservation, maintaining quality attributes and reducing browning for up to 7 days in potato and apple, and up to 3 days in mushroom. The findings demonstrate that Hicaz pomegranate peel extract is an effective natural PPO inhibitor capable of extending the shelf life of fresh-cut produce. Its potential applications in food preservation highlight both its economic value as a waste-derived resource and its contribution to sustainable food processing. © 2025 Society of Chemical Industry.