Palm Frond Phenolic Extract-Loaded PVA Films as Active Packaging for Barhi Dates: Structure, Antioxidant Properties, and Quality Preservation

Abstract

This study developed bioactive polyvinyl alcohol (PVA) films loaded with palm frond phenolic extract (PFX) and evaluated their use as active packaging for fresh Barhi dates. HPLC identified catechin (12.3 mg/g), epicatechin (9.8 mg/g), gallic acid (8.4 mg/g), and procyanidin B1 (6.5 mg/g) as the main phenolics, consistent with high total phenolic content (287.4 mg GAE/g) and DPPH activity (90.25%). PFX incorporation slightly increased film thickness (61.0–63.0 μm), caused mild yellowing, reduced water contact angle, decreased tensile strength, and improved elongation at break at moderate loading. Water vapor permeability and water solubility increased as PFX concentration increased, probably because polar phenolic compounds increased hydrophilicity and reduced polymer-network compactness. Conversely, antioxidant functionality improved markedly, with film phenolics reaching 2.16 mg GAE/g and DPPH activity reaching 65.11%. Among the formulations, PVA/PFX2, prepared with 0.50 g PFX per 100 mL film-forming solution, showed the best balance of mechanical performance, antioxidant activity, and handling properties. During refrigerated storage, PVA/PFX2 reduced weight loss, maintained firmness, slowed changes in soluble solids and acidity, and enhanced phenolic content and antioxidant activity compared with air and stretch-film controls. These results support palm fronds as a sustainable phenolic source for active packaging.