Modification of physicochemical, antioxidant, and antibacterial properties of chitosan films with cinnamaldehyde-tannic acid-metal particles

This study aimed to develop and characterize novel chitosan (CS)-based composite films by incorporating metal-phenolic networks (MPNs) assembled from cinnamaldehyde (CA), tannic acid (TA), and five different metal ions (Ca 2+ , Mg 2+ , Zn 2+ , Cu 2+ , or Fe 3+ ). The objection was to evaluate the impact of metal ion type on the films' physicochemically and functional properties for potential active packaging application. The results demonstrated that the incorporation of cinnamaldehyde-tannic acid-metal (CTM) particles significantly enhanced the films’ performance. Notably, the Zn 2+ -based (CTZn) film exhibited the most pronounced improvement in tensile strength (269 % increase) and hydrophobicity (water contact angle = 97.50°). All CTM composite films showed enhanced thermal stability, reduced water vapor permeability, and excellent UV-blocking capacity compared to the pure CS film. Furthermore, the composite films displayed stronger antibacterial activity and higher antioxidant activity than the control. In conclusion, CTM networks, especially those involving Zn 2+ , effectively enhance the multifunctional properties of CS films, making the developed composite promising candidates for high-performance, active food packaging materials.