Engineeringa Natural Multifunctional Biomass-BasedComposite Nanosystem for Active Smart Packaging and Colorimetric Labels

Here, a series of novel multifunctional active smart packaging films (CPTA<i>n</i>) with ammonia sensing and extended food freshness were prepared by using chitosan (CS) and poly(vinyl alcohol) (PVA). Titanium dioxide nanoparticles (TiO₂ NPs) and purple cabbage anthocyanins (PKA) were used as functional additives. The CPTA(<i>n</i>) has excellent physical and mechanical properties, antimicrobial properties, UV-blocking properties, and antioxidant activity. Especially, when in a subambient atmosphere, the surface temperature of the CPTA-3 film is reduced by ∼9.6 °C, offering significant advantages for food storage and low-temperature transport over traditional packaging materials. The application of CPTA(<i>n</i>) film in banana preservation showed that the shelf life of bananas packaged with CPTA(<i>n</i>) film could reach at least 10 days. Similarly, the colorimetric dipsticks prepared from CPTA-0 and CPTA-3 were successfully applied to the freshness monitoring of shrimp. This investigation provides a novel perspective on the development of intelligent active packaging with broad applications in seafood and fruit preservation.