Bioactive chitosan/ellagic acid films with UV-light protection for active food packaging

Homogeneous, translucent and flexible films of chitosan (CH) and ellagic acid (EA) were prepared by solvent casting. Various concentrations of EA (0.5, 1.0, 2.5 and 5.0% w/w relative to CH) were used in order to evaluate their UV-blocking properties. In addition, the photochemical stability of the films was also studied via artificial solar light irradiation. These set of films display high mechanical properties (Young’s modulus = 3.21–3.57 GPa), thermal stability up to 215–220 °C, UVA- and UVB-barrier properties, moderate water vapor permeability (WVP = 2.82–3.70 g mm m−2 day−1 kPa−1) and maximum antioxidant activity around 28% (DPPH scavenging activity). Furthermore, all CH/EA films show antimicrobial activity against food-borne pathogens such as Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria due to the CH antimicrobial effectiveness. These bioactive UV-blocking CH/EA films open the way to materials with potential for eco-friendly active packaging.