Abstract:The physicochemical properties and structural characteristics of chitosan (CS)/pullulan (LP)/polyvinyl alcohol (PVA)/collagen (GL) food packaging films were studied using CS, LP, PVA, and GL as raw materials and mixed at certain proportions. A multi-component composite film was prepared using the film casting method, and the mechanical properties, water solubility, swelling rate, chromaticity, and light transmittance of the composite film were measured. The structure of the film was characterized via infrared spectroscopy, X-ray diffraction spectroscopy, and scanning electron microscopy. When CS, LP, and CS-LP membranes were added to PVA-GL in that order, the thickness and elongation at break of the composite film increased gradually but tensile strength decreased gradually. The thickness of the quaternary membrane was 142.50 μm, its tensile strength was 11.21 MPa, and elongation at break was 169.24%. The expansion rate of the composite film was increased but its solubility was reduced. The expansion rate of the quaternary film was the highest and its solubility was the lowest, at 368.16% and 58.64%, respectively. The measurements of chromaticity and opacity revealed that the quaternary film was brighter and showed a smaller color difference, with the lowest opacity of 2.28 UA/mm. The transmittance of UV and visible light in the wavelength range of 200~800 nm was measured, and the film showed excellent UV-blocking ability. Finally, infrared spectroscopy, X-ray diffraction spectroscopy, and scanning electron microscopy revealed that CS and LP interacted with PVA-GL, reduced the crystallinity of CS and LP, and formed a dense homogeneous system. These findings provide a scientific basis for further research on CS/PL/PVA/GL food packaging films.
