Engineering a Natural Multifunctional Biomass-Based Composite Nanosystem for Active Smart Packaging and Colorimetric Labels

Here, a series of novel multifunctional active smart packaging films (CPTAn) 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(n) 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(n) film in banana preservation showed that the shelf life of bananas packaged with CPTA(n) 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.