High-barrier cellulose-based packaging material for enhanced food preservation with visual freshness monitoring

In recent years, there has been a growing interest in the development of cellulose or nanocellulose (CNF) materials in food packaging industry due to their green and processable nature, while the inherent hydrophilicity of cellulose presents significant challenges in meeting the high barrier requirements essential for food packaging applications. In this study, a dual strategy of internal cross-linking and external functional coating was employed to fabricate high-barrier nanocellulose-based packaging. Dialdehyde CNF (DCNF) was incorporated into pristine CNF to form a dense cross-linking network containing hemiacetal linkages and hydrogen bonds. Additionally, an ethyl cellulose (EC)/curcumin (Cur) coating was applied to further improve hydrophobicity while leveraging curcumin’s pH-responsive properties for visual monitoring. The influence of DCNF oxidation time and CNF incorporation ratio on film crystallinity and water resistance was systematically studied. The synergistic interaction of DCNF/CNF crosslinking and surface coatings endows the composite membrane (DCNF 1-75 /CNF/ECCur) with exceptional barrier properties, achieving a 44% reduction in water vapor transmission rate and 99% suppression of oxygen transmission rate. Moreover, the film demonstrated multifunctional properties: over 99.9% antibacterial efficacy against Escherichia coli and Staphylococcus aureus , 91% antioxidant activity, effective food preservation capability along with visual monitoring functionality. This work provides a novel approach for designing multifunctional nanocellulose-based intelligent packaging materials.