| Abstract Scope |
Petroleum-derived films dominate food packaging yet are non-renewable, non-degradable, and functionally passive. We present a fully biobased, compostable nanocomposite film platform that pairs natural-fiber reinforcement with melanin-based hybrid nanoparticle microcapsules to deliver combined antioxidant, antimicrobial, and UV-shielding functionality. Melanin nanoparticles—produced by natural sepia and synthetic dopamine-oxidation routes—are integrated with biogenic MgO/ZnO and with nanocellulose and nanochitin to form inorganic and organic hybrids, then encapsulated by chitosan–gelatin complex coacervation and spray drying into 1–10 µm microcapsules. Capsules are dispersed at 0.25–2 wt% in poly(lactic acid)–PHBV matrices by solvent casting and twin-screw extrusion using MA-g-PLA/OLA compatibilizer, and demonstrated as paper coatings. Films are evaluated for mechanical, thermal, barrier, and optical performance, targeting ≥30% oxygen- and ≥15% water-vapor-permeability reductions with ≥90% visible transmittance, alongside ASTM D6400 compostability. A parallel technoeconomic assessment benchmarks biogenic versus chemical nanoparticle routes. Collectively, this work advances natural-fiber biocomposites toward safe, sustainable, high-performance active food packaging. |