Coconut Waste as a Functional Platform for Biopolymer-Based Food Packaging Films: A Comprehensive Review

Petroleum-based plastic packaging has led to severe environmental concerns, whereas biopolymer films, despite their sustainability, often suffer from limited mechanical strength, poor moisture resistance, and insufficient functional activity. Coconut by-products represent an abundant and renewable resource with significant potential to address these limitations and support circular economy strategies in food packaging. This review provides a comprehensive and critical synthesis of recent advances in coconut-based functionalized biopolymer films, systematically covering the sources, extraction, and modification of key coconut-derived materials, including cellulose, coconut oil, polyphenol-rich extracts, and coconut proteins. A structure-property-function perspective is adopted to elucidate how these components influence the mechanical, barrier, and functional performance of composite films. Coconut nanocellulose serves as an effective reinforcing phase, enhancing mechanical strength, barrier properties, and thermal stability, while also enabling active and intelligent packaging functionalities. Coconut oil improves hydrophobicity, flexibility, and antimicrobial activity, although its compatibility with hydrophilic matrices remains a key challenge. Polyphenol-rich extracts impart antioxidant and antifungal properties and, in anthocyanin-rich systems, enable pH-responsive colorimetric sensing. Coconut proteins exhibit intrinsic film-forming capability and contribute to structural integrity. Overall performance is strongly governed by component selection, interfacial compatibility, and compositional balance within multicomponent systems. However, key challenges remain, including raw material variability, instability of bioactive compounds, limited scalability, and concerns regarding migration safety. Future research should focus on interfacial engineering, stabilization of multicomponent systems, and the development of scalable processing strategies to facilitate practical applications in sustainable food packaging.