Development of multifunctional green food packaging based on chitosan and quercetin for visual monitoring of fish spoilage

A significant surge has occurred in the utilization of the active films sourced from biopolymers, which help to improve the preservation period of foods. In this study, a chitosan-quercetin (Chit-Quer) active packaging film with excellent adhesion, tensile properties, and shape memory was developed, which are conducive to enhancing the sealing and stability of packaging, and are able to adapt to complex shapes and irregular surfaces. The incorporation of quercetin resulted in a rougher and more porous structure of the Chit-Quer composite film with enhanced hydrophilicity and reduced swelling index. The addition of quercetin increased the antimicrobial activity of the composite film to over 90 %. Furthermore, both the oxidized and reduced states of quercetin significantly improved the film’s oxidative resistance. The reduced Chit-Quer film showed the strongest free radical scavenging ability, reaching 80 % within just 5 min, which was a tenfold improvement over the pure chitosan film. In addition, the Chit-Quer film can be completely degraded in about 70 days. Based on the colorimetric alteration of the Chit-Quer film in different pH environments, we further demonstrate that it can be served as an intelligent packaging film for the instant monitoring of crucian carp spoilage. These results indicate that the developed Chit-Quer film is expected to have a substantial impact in the realm of active food packaging, providing more efficient and sustainable protection for food preservation and safety.