Preparation of chitosan/lignin nanoparticles-based nanocomposite films with high-performance and improved physicochemical properties for food packaging applications.

Chitosan (CH)-based composite films have attracted increasing attention as promising green food packaging materials due to their biodegradability and ease of fabrication. Additionally, lignin (LN) has been widely used as additive for chitosan-based films to improve their physicochemical properties. In this study, a series of composite films made of chitosan nanoparticles (NCH) as a matrix and alkali lignin nanoparticles (LNPs) as functional filler were prepared. The NCH-LNPs composite films exhibited a more uniform appearance and enhanced crystallinity compared to NCH-LN films. The maximum pyrolysis temperature of NCH-LNPs films, determined by TG, reached 309 °C. Moreover, the antioxidant capacity of NCH-LNPs film was 1.5 and 3.4 times higher than those of NCH-LN and NCH films, respectively. The tensile modulus of NCH-LNPs films increased by 8.9 % and 36.5 %, while the tensile strain decreased by 16.0 % and 52.8 % compared to NCH and NCH-LN films, respectively. Finally, the suitability of prepared films for food preservation was studied on grape and cheese samples. The ability of NCH-LNPs films to inhibit lipid peroxidation in cheese was 2 times higher than that of NCH-LN films. These results showed that the improvement of physicochemical properties of NCH-based films by LNPs was significantly higher than that observed with LN.