Microporous chitosan/polyvinyl alcohol based active packaging materials with integrated gas-transmission, radiation-cooling, anti-microbial, and ultraviolet shielding features

Active packaging materials transform the packaging from a passive barrier to active control, responding to consumers' demand for safer, healthier, and higher quality food and prolonging the shelf life of foods. Herein, a novel microporous chitosan/polyvinyl alcohol (CS/PVA) based biodegradable active packaging material (microporous membrane doped with 0.3 wt% nanometer TiO2, referred as MT3) was nanoengineered with integrated gas transmission, radiation cooling, anti-microbial and quality control characteristics. The particle leaching method realized the on-demand microporous structure, enabling an impressive CO2 permeability. Furthermore, TiO2 nanoparticles were filled in MT3 as functional fillers to achieve good radiation cooling, anti-bacterial and ultraviolet shielding functions. In addition, MT3 exhibited the typical features of packaging materials, such as sufficient hydrophobicity and mechanical and barrier performances. Interestingly, the superficial temperature of MT3 reduced by ∼ 6.4 °C due to its excellent radiation-cooling properties under a sub-ambient atmosphere. Thus, the on-demand comprehensive material design enabled MT3 to exhibit an enhanced shelf life of 168 h, which is difficult to achieve with conventional preservative films at room temperature. These results encourage the further use of MT3 films as multi-functional active packaging materials. This study provides a green and feasible method for the production of promising active packaging functional materials, which can be widely used in fresh fruit and vegetable preservation packaging.