Sodium Phytate‐Enhanced Chitosan Films: Preparation, Characterization and Cherry Tomato Preservation

The pursuit of high‐performance and sustainable food packaging films requires the development of materials based on environmentally friendly resources. Here, we proposed a multi‐cross‐linking strategy based on sodium phytate and prepared chitosan‐sodium phytate (CS‐PA) film. The strategy enhanced the mechanical and functional properties of chitosan films while allowing them to have a denser structure and a thinner thickness. The results of mechanical properties showed that the addition of sodium phytate increased the tensile strength of chitosan film to 1.79 times and the elongation at break to 1.45 times. CS‐PA films exhibited better hydrophobicity, UV, and water vapor barrier compared to CS films. The FTIR examination of the films and their stability in NaCl and urea revealed that the amino group in chitosan and the phosphate group in sodium phytate interact. Importantly, the CS‐PA‐3.2 film had a 99% inhibition rate against Escherichia coli and Staphylococcus aureus , and a 98.43% scavenging rate against ABTS + . Moreover, CS‐PA film can significantly reduce the weight loss rate and titratable acid degradation of cherry tomatoes as well as inhibit microbial growth and the reduction of total phenol content, thus extending shelf‐life and providing a potential alternative to synthetic packaging.