Ferulic acid-regulated anthocyanin-based intelligent film: A promising strategy to improve stability, sensitivity, and biological activity.

The attractive color of anthocyanins makes them highly desirable in active intelligent food packaging. However, the poor stability has significantly restricted their applications. In this study, a novel collagen hydrolysate-chitosan-red cabbage anthocyanin-ferulic acid (CH-CS-RCA-FA) intelligent film with high stability and bioactivity was prepared. The addition of FA not only changed structural characteristics of the film, but also endowed it with functional benefits. FA cross-linked with CH-CS-RCA through hydrogen bonding, electrostatic, and hydrophobic interactions, improving mechanical properties and water resistance of the film. FA significantly enhanced the color rendering and storage stability of the film, resulting in pronounced color change in pH 7.0-8.0 range and the increase of ammonia (NH) sensitivity of the film. Owing to high bioactivity of FA, the radical-scavenging and bacterial inhibition rates of the CH-CS-RCA-FA film were significantly higher than those of the CH-CS-RCA film. In salmon preservation, the shelf-life of salmon after CH-CS-RCA-FA coating treatment was extended from 6 d to 12 d at 4 °C. The freshness indication sensitivity of the CH-CS-RCA-FA film was higher than that of CH-CS-RCA, especially at the medium-fresh stage. Therefore, this work provides an effective idea for the optimization of anthocyanin-based intelligent packaging systems.