Preparation and characterization of highly stable pH-sensitive multifunctional films based on co-pigment-anthocyanin conjugate system for pork monitoring and preservation

Although there is a large volume of literature on pork quality monitoring and bacteriostatic film preparation, the successful development of a packaging film that performs both functions still faces significant technical challenges. In this study, a highly stable pH-sensitive smart packaging film with freshness preservation function was prepared by using anthocyanin-co-pigment (polylysine, catechin, and ferulic acid) complex as the active ingredient and potato starch-carrageenan as the matrix. The pi-pi stacking and hydrogen bonding interactions between the introduced co-pigments and anthocyanins significantly improved the shelf life and color stability of anthocyanins compared to pure anthocyanin films. In addition, the introduction of co-pigments effectively improved the tensile strength (38.37%similar to 87.49%) and barrier properties of the films, and maintained the high anthocyanin retention (38.37%similar to 91.07%), antioxidant (70%) and antimicrobial (especially against Staphylococcus aureus) properties of the films under extreme conditions (prolonged exposure to light and 55 degrees C). The epsilon-polylysine-anthocyanin composite film effectively extended the shelf life of pork by up to 40 h compared to pork stored at 25 degrees C (24 h). In addition, the color variation of the film (RGB values) was combined with pork freshness through the "Color Coll" mobile application, which effectively reduces the variability of visual identification between individuals and enables visual quantitative analysis of pork quality. Therefore, this study has great potential for monitoring changes in meat quality and extending its shelf life.