Intelligent active packaging of sodium alginate and pectin mixed with Aronia melanocarpa anthocyanins and tea polyphenols for shrimp freshness monitoring and preservation.

In this study, an intelligent active packaging film was developed using sodium alginate (SA) and pectin (PC) as the film matrix, with Aronia melanocarpa anthocyanins (AMA) as a pH-sensitive indicator and tea polyphenol (TP) added to stabilize the anthocyanins. The results demonstrated that AMA and TP formed hydrogen bonds with polysaccharides, which reduced the surface roughness of the film and enhanced the compatibility of the component. The interaction between TP and AMA improved the stability of AMA, leading to an increase in anthocyanin retention rate from (29.56 ± 1.22)% to (40.67 ± 1.83)% after 4 days of UV irradiation. The addition of TP significantly enhanced the tensile strength (from 3.13 MPa to 4.26 MPa), UV-blocking properties, and antioxidant activity (with DPPH and ABTS radical scavenging activities being 4.8 and 9.6 times higher than those of the SA/PC film), as well as the antibacterial properties of the film. Additionally, the film exhibited a distinct color response to pH changes. Finally, the films were successfully applied to preserve shrimp and provide real-time visual monitoring of freshness. The results indicated that the SA/PC/AMA-2/TP film extend the shelf life of shrimp by approximately 12 h compared with the control group, making it a promising new food packaging material with potential applications.