Intelligent indicator film integrated with Vitis amurensis anthocyanin for fish freshness monitoring

As a functional extract of green agricultural resources, anthocyanins possess significant potential as a source of intelligent packaging materials. A novel intelligent indicator film was developed by combining Vitis amurensis anthocyanins (VAA) with soy protein isolate (SPI) and chitosan (CS). The incorporation of anthocyanins enhanced both the mechanical and barrier properties of the films. Furthermore, the optimized concentration VAA had a beneficial effect on crystalline structure and could provide VAA/SPI/CS film with excellent DPPH scavenging ability. Packaging fresh fish with the film significantly improved quality parameters. Additionally, as the pH changes, the films exhibited noticeable color changes, transitioning from fuchsia to dark green. These findings suggest that VAA/SPI/CS intelligent indicator films can effectively monitor fish freshness in real-time through color changes, precisely because fish spoilage can cause color changes in the film.