Development and Application of a Novel pH-Responsive Bilayer Indicator Film for Yellowfin Seabream Preservation and Freshness Monitoring

A pH-responsive bilayer film was developed for real-time freshness monitoring and preser- vation of yellowfin seabream. The emulsified layer contained chitosan (CS) and flaxseed oil (FO), while the indicator layer comprised carrageenan (CAR), gelatin (GEL), grape seed anthocyanins (GSA), and curcumin (CUR). Optimization via response surface method- ology determined the ideal formulation: CAR/GEL mass ratio 1.11:1, CS concentration