Nanocellulose for sustainable food packaging: Progress, challenges, and future directions

Nanocellulose (NC) has emerged as a promising functional component for sustainable food packaging systems because of its renewable origin, biodegradability under controlled conditions, and reinforcing and barrier-forming capacity. Based on a structured literature search and descriptive synthesis, this review provides a critical and integrative assessment of: (i) the structural and physicochemical fundamentals of NC, including cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial nanocellulose (BNC); (ii) recent advances in NC-containing food packaging; (iii) bioactive and sensing functionalities for active and intelligent packaging; (iv) techno-economic, environmental, regulatory, and scalability challenges; and (v) future research priorities. Comparative evidence indicates that NC-containing composites can improve tensile strength and oxygen barrier performance relative to selected bioplastics, particularly under low-humidity conditions. However, practical implementation remains constrained by moisture sensitivity, high production costs, limited industrial scalability, non-harmonized regulations for food-contact nanomaterials, and insufficient validation under real-use and shelf-life conditions. Life cycle assessment (LCA) studies indicate that NC-containing systems can reduce environmental burdens when lignocellulosic residues and optimized production routes are used, although these benefits depend on feedstock, processing route, functional modification, and end-of-life scenario. Emerging directions include green extraction, artificial intelligence (AI)-assisted design, circular-economy alignment, migration and safety assessment, and application-specific validation. Overall, this review provides actionable guidance for advancing NC-containing packaging systems from laboratory feasibility toward industrially relevant, safe, and environmentally responsible applications.