Preparation of tuna skin gelatin-polyphenol intelligent packaging film and its application in the preservation of tuna.

To address aquatic product preservation challenges, this study developed an intelligent label leveraging natural pigments' antibacterial and responsive properties. A composite film integrating purple sweet potato anthocyanins and curcumin was fabricated via blow-spinning technology. The gelatin-polyvinyl alcohol-chitosan interpenetrating polymer network significantly enhanced film properties, including hydrophobicity (water contact angle: 102.8° ± 1.56°), thermal stability (Peak heat absorption:123 °C), and elongation at break (stress: 1.18 kg/mm2, stain: 43 %). The film delayed tuna spoilage through synergistic mechanisms: curcumin disrupted bacterial biofilm integrity (total bacterial count reduced by 3.37 log CFU/g), inhibited lipid oxidation, while the curcumin/anthocyanin composite film (GC-CR/ATH) reduced metmyoglobin content to 21.8 g/s and delayed browning. The PVA-incorporated GCP-CR/ATH film optimized sustained release of active compounds and maintained fish texture (springiness: 0.42 mm, hardness: 12.5 N) via "antibacterial-antioxidant-pH responsive" synergy. This work provides theoretical support for real-time freshness monitoring and active packaging in aquatic products.