pH-responsive zein/chitosan composite film containing cinnamon essential oil-loaded Pickering emulsion and black wolfberry anthocyanin: Physicochemical properties, and application in packing salmon.

With the rapid development of smart packaging, traditional systems that only extend shelf life or monitor freshness no longer meet consumer demands. This study developed a pH-responsive zein/chitosan composite film incorporating cinnamon essential oil-loaded Pickering emulsion (CEOP) and black wolfberry anthocyanins (BWAN) to extend salmon shelf life and monitor freshness. The composite films' structure, physical properties, pH sensitivity, antioxidant, and antimicrobial characteristics were evaluated. Incorporating 1 % CEOP enhanced the film's mechanical strength (from 11.44 MPa to 25.49 MPa), antioxidant capacity (from 61.9 % to 85.6 %), and antimicrobial effects. FTIR, XRD, and SEM confirmed strong molecular interactions between CEOP, BWAN, and the film matrix, improving stability. The composite film extended salmon's shelf life by 6 days and exhibited dynamic color changes, providing real-time freshness monitoring. This multifunctional film offers an innovative solution for food preservation with intuitive indicators of food quality.