Preparation and characterization of citric acid crosslinked konjac glucomannan/surface deacetylated chitin nanofibers bionanocomposite film

Novel bionanocomposite films were prepared by combining konjac glucomannan/surface deacetylated chitin nanofibers (KGM/S-ChNFs) with different concentrations of citric acid (CA) (10%–25%) via a solution casting method. The effect of CA-induced crosslinking on the rheological behavior of film-forming solutions (FFS) as well as the structural and physicochemical properties of the resulting bionanocomposite films were evaluated. The results revealed that the increased CA loadings increased the shear viscosity of FFS. Fourier transform infrared spectra and scanning electron microscopy results confirmed the successful crosslinking between CA and S-ChNFs. The addition of 20 wt% CA was defined as the optimal condition, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile strength and antimicrobial properties. This work supported the conclusion that CA crosslinking was an effective pathway for the preparation of polysaccharide-based bionanocomposite films with improved properties, which may be a promising material for active food packaging applications.