Development of a functional composite film based on pomelo peel waste and sodium hyaluronate for mango preservation

In response to environmental pollution and resource depletion caused by petroleum-based plastics, safe and renewable bio-based food packaging materials are increasingly sought. In this study, pomelo peel was utilized as a biopolymer matrix, sodium hyaluronate as the film-forming framework, and the natural antibacterial peptide nisin was incorporated to develop an eco-friendly functional film with enhanced barrier, antioxidant, and biocompatible properties, and its application in mango preservation was evaluated. Optimization identified an optimal pomelo peel powder content of 0.6 wt%, producing a film with low water vapor permeability (2.2 × 10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹), high tensile strength (23.68 MPa), excellent UV shielding, a water contact angle of 104°, and a DPPH scavenging activity of 79.17%. Incorporation of 1.5 mg/mL nisin achieved 100% inhibition of Staphylococcus aureus without significantly affecting barrier performance or thermal stability. Biosafety assays demonstrated its preliminary biocompatibility. In mango storage trials, the composite film effectively delayed ripening and senescence; after 12 days, fruit firmness loss was significantly reduced, soluble solids accumulation was postponed with moderate decline, titratable acidity remained at 0.82%, and brightness exceeded that of PE-packaged fruit. This work presents a potentially environmentally friendly bio-based packaging film that integrates waste valorization, multifunctional preservation, and biosafety, offering a promising strategy for fruit preservation and the high-value utilization of agricultural by-products.