Anthocyanins loaded bilayer films based on polysaccharides assisted by machine learning for fish freshness monitoring

Novel multifunctional packaging for monitoring and maintaining food freshness has been developed. Bilayer films based on polysaccharides incorporating red cabbage anthocyanins were prepared. Anthocyanins were encapsulated in the inner layer based on κ-carrageenan or alginate hydrogel, while the chitosan hydrogel was used as a protective outer layer. Carrageenan-anthocyanin-chitosan films demonstrated homogeneity, and fast pH and NH₃ responsiveness. The film exhibited significant antimicrobial activity and excellent antioxidant activity (87 %). To establish a quantitative relationship between film color and fish freshness using machine learning models, the films were exposed to different ammonia concentrations, and the corresponding color responses were recorded. The artificial neural network demonstrated the best performance, achieving a R² score of 0.984. Finally, storage of trout fillets was monitored for 12 days at 4 °C. The results confirmed the excellent potential of the bilayer films, which could be, in combination with machine learning models, effectively applied for monitoring food safety.