Carboxymethyl chitosan incorporated with gliadin/phlorotannin nanoparticles enables the formation of new active packaging films

Advanced carboxymethyl chitosan (CMCS) based functional films were fabricated by involving some amounts of gliadin/phlorotannin nanoparticles (GPNPs) using a solution casting method. GPNPs were synthesized by an antisolvent precipitation approach, and they presented a spherical morphology with a mean diameter of 145.30 ± 2.06 nm. The effect of GPNPs concentration on the structural, physical, antioxidant and antimicrobial properties of CMCS-GPNPs (C-G) functional films was evaluated. It was found that the added GPNPs were homogeneously distributed over the whole CMCS matrix, allowing to reduce the free volume of the nanocomposite matrix and subsequently improve the physical properties of the final film (evidenced by mechanical and water barrier properties). FT-IR spectra indicated the intermolecular interactions, such as hydrogen bonds and electrostatic interaction, within the matrix of the nanocomposite films were increased. Impressively, the anti-ultraviolet properties, antioxidant activity and antimicrobial behaviors of the as-formed C-G functional films were greatly enhanced compared to the pure CMCS film. All these results suggested that our as-prepared C-G nanocomposite films could be a promising food packaging material.