Two different fabrication method of high-hydrophobic Bi-layer indicators based on sodium alginate-polyvinyl alcohol/chitosan-zein incorporated with alizarin@ZIF-8 for beef freshness visualization.

Intelligent films are essential for real-time monitoring of food spoilage. However, the application is often limited by challenges such as hydrophilicity and color instability. In this study, two high hydrophobic bilayer indicators based on sodium alginate-polyvinyl alcohol/chitosan-zein with alizarin grafted onto ZIF-8 carrier (AL@ZIF-8) were fabricated using the casting method and electrospinning, respectively.