Pullulan/chitosan-based functional film incorporated with curcumin-integrated chitosan nanoparticles

We report the preparation of curcumin-integrated chitosan nanoparticles (CNP@Cur) and utilize them to fabricate functional films based on mixed biopolymers (pullulan and chitosan). Curcumin is a well-known bioactive functional filler in food packaging, so we developed CNP@Cur as a functional nanofiller. The fabricated nanofillers were approximately spherical with a size of about 20-50 nm, as observed by FE-SEM. Additionally, the developed CNP@Cur was very stable in an aqueous solution (zeta potential -50 mV). The chemical interaction of curcumin and chitosan was checked using FTIR spectra and XRD. The bio-based active packaging film was fabricated by adding different content of CNP@Cur (0, 1, 2 & 4 wt%) to the pullulan/chitosan (50:50) polymer matrices using a solution casting process. The addition of functional nanofillers remarkably enhanced the mechanical strength (-15 %), UV-light shielding properties (-80 %), and hydrophobicity (-18 %) without much reducing the transparency (-20 %) of the film. The water vapor barrier property of the film was also slightly improved. In addition, CNP@Cur on nanocomposite films showed significant improvement in antioxidant activity (DPPH and ABTS assays) and slightly increased antibacterial activity against E. coli and L. monocytogenes. Thus, blending bioactive functional nanofillers improved the bio-based film's physical and functional properties, which could be applied for active food packaging and biomedical purposes.