Valorization of Larix decidua Mill. bark by functionalizing bioextract onto chitosan films for sustainable active food packaging

The present study explored the use of chitosan films functionalized with antioxidants extracted from Larix decidua Mill. bark for active packaging. The pristine chitosan and extract-incorporated chitosan films were evaluated for their structural, physico-mechanical, thermal, viscoelastic and antioxidant properties using advanced characterization techniques. The infrared spectroscopy revealed hydrogen bonding between the extract polyphenolic antioxidants and chitosan, whereas the surface microscopy studies indicated good compatibility between them. The addition of bark extract caused a significant increase in color parameters and solubility with reduction in swelling and elongation at break of the films. The thermal analysis indicated a drop in thermal stability of chitosan films modified with the extract. The dynamic mechanical analysis confirmed the extract-polymer interactions and the viscoelastic nature of the films. The incorporation of bark extract caused remarkable enhancement in the antioxidant activity of chitosan films. Overall, larch bark extract-functionalized chitosan films demonstrated promising potential for food packaging. •Active packaging films developed with larch bark extractives and chitosan•Extract altered the physico-mechanical properties and microstructure of the films.•Non-covalent interactions observed between bark extractives and chitosan•Huge increase in antioxidant activity of extract-functionalized chitosan films•Good compatibility found between bark extract and chitosan matrix