Green fabrication of lignin nanoparticles/chitosan films for refrigerated fish preservation application

Maximizing the waste valorization of renewable resources to develop biocomposite materials is highly desirable regarding environmental sustainability and food chain security. Herein, lignin nanoparticles (LNPs) obtained using deep eutectic solvent (DES) by anti-solvent strategy were employed as nanofillers in the chitosan matrix to fabricate novel bioactive packaging films. The results showed that adding LNPs reduced the swelling degree and water vapor transmittance of chitosan films. Upon introduction of LNPs content, the tensile strength of the composite films significantly increased by about 40%, whereas the elongation at break showed an opposite trend. When the content of LNPs was 10 wt %, the UV shielding and free radical scavenging ability of the composite films reached the maximum point. However, the diameter of the inhibition zone only increased at the addition of 1 wt%. Furthermore, the refrigerated (4 ± 1 °C) grass fish wrapped with composite films revealed better quality and the shelf life was extended to 10 days. Therefore, nanocomposite films provide an attractive and promising pathway for high value-added commercial utilization of lignin and chitosan for food packaging applications.