Formation chitosan-based hydrogel film containing silicon for hops β-acids release as potential food packaging material

Hydrogel film composed of chitosan (CS) as raw material was prepared by free radical polymerization. Silicon was introduced into the hydrogel film in different ways (covalent/non-covalent) to improve the physical properties of the film, and beta-acids were loaded to enhance the antibacterial activity of the film. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis were used to characterize the structure of films. The mechanical results indicated that when nano-silica (0.3%) was introduced into film (containing 0.2% beta-acids) by non-covalently bond, the tensile strength increased to 8.59 MPa. Meanwhile silicon (0.3%) entered the film by covalent bonding, the tensile strength increased to 7.99 MPa. The films loaded with beta-acids had well ability to blocks ultraviolet rays and exhibited inhibitory effect on E. coli and S. aureus. In the PBS (37 degrees C, pH = 7.4) simulant solution, the release mechanism of most films to release the beta-acids followed non-Fick diffusion (n > 0.5). It could be concluded that the prepared hydrogel films loading with beta-acids had broad application prospects in food packaging material with antibacterial property and controlled release.