Double-encapsulated modified silica/nanocellulose composite film with cherry preservation

Ordinary nanocellulose films suffer from poor barrier properties, rendering them ineffective at preventing microbial invasion of food. Herein, double-embedded modified silica/copper nanoparticles/E2H preservative (NE) was obtained by in-situ immobilized copper nanoparticles (CuNPs) and simultaneously loading trans-2-hexenal (E2H) onto modified hollow mesoporous silica through imine bonds and pore channels. Subsequently, a high-barrier nanocellulose-based film (NE/CNF) capable of sustained release of copper active factors and E2H was developed by integrating the NE preservative with nanocellulose. The results demonstrate that modified silica exhibits controlled-release effects on both active factors: the cumulative release of E2H reached 77.98% within 7 days, while that of copper active factors reached 0.67% over 15 days. Benefiting from this controlled-release design, NE/CNF film has excellent antibacterial and antioxidant activities. Additionally, NE/CNF films possess excellent mechanical and barrier properties, especially showing a very low oxygen transmission rate (0.388 10^-8 g/s·m²). Therefore, NE/CNF films demonstrate effective preservation performance on cherries, significantly extending their shelf life to 12 days at room temperature.