Recent advances and critical insights of cellulose nanocrystals in active food packaging

With the growing demand for food safety and environmentally sustainable packaging, the development of active packaging materials that combine preservation performance with ecological compatibility has become a major research focus. Cellulose nanocrystals (CNCs), owing to their high crystallinity, excellent mechanical properties, barrier potential, surface functionalizability, and biodegradability, have emerged as promising bio-based building blocks for active food packaging. This review systematically summarizes recent advances in CNC-based active food packaging, with emphasis on their sources and production methods, structure-function characteristics, and roles in barrier enhancement, active-compound loading and controlled release, antimicrobial and antioxidant performance, and multifunctional synergistic systems. Current studies show that CNCs can improve structural stability and gas-barrier performance while also serving as Pickering emulsion stabilizers, carriers of active compounds, and interfaces for release regulation, thereby enhancing the dispersion stability and sustained efficacy of essential oils, natural extracts, and inorganic active components. With these properties, CNC-based active packaging has shown considerable potential in preserving fruits and vegetables, meat products, dairy products, aquatic foods, and ready-to-eat foods. Future advances in interfacial engineering, processing technologies, multifunctional stability, and standardized regulatory and safety evaluation are expected to support broader practical application and industrial translation.