Self-assembled Chitosan/Polyvinyl alcohol hydrogel film incorporated with TiO2 with excellent stability, mechanical and antibacterial properties for the preservation of chilled pork

The antibacterial active packaging's highly effective bacteriostatic property is essential for extending the shelf life of chilled meat. The present study fabricated an antibacterial hydrogel film by utilizing chitosan (CS) and polyvinyl alcohol (PVA) as the substrate supplemented with TiO₂. The SEM results revealed that the PVA/CS hydrogel film, cross-linked with citric acid as a cross-linking agent, exhibited smooth surface and consistently cross-sectional morphology. The FTIR analysis revealed that the incorporation of TiO₂ resulted in a reduction in the cross-linking effect of CS and PVA, as well as a decrease in the film's break elongation. The incorporation of 0.20 % TiO₂, however, significantly enhanced the tensile strength, water barrier property, water absorption capacity, and thermal stability of the film. The 0.20 %TiO₂/PVA/CS composite exhibited significant antibacterial activity against Pseudomonas and Acinetobacter putrefaction in chilled pork meat, as demonstrated by in vitro experiments. The preservation experiment demonstrated a synergistic antibacterial effect between CS and TiO₂, leading to a significant reduction in microbial growth during storage. The addition also enhanced the water retention properties of meat and effectively extended the shelf life of pork to 15 d. The findings indicate that the TiO₂/PVA/CS demonstrates significant potential for application as an innovative packaging material.