Preparation of chitosan/peony (Paeonia suffruticosa Andr.) leaf extract composite film and its application in sustainable active food packaging.

Considering the problem of food perishability and the environmental pollution of plastic packaging, the natural active packaging prepared by incorporating plant leaf (e.g. peony leaf) extract into biodegradable food packaging materials may be a key to addressing these issues. In the study, a novel green bioactive composite film (CS-PLE) with antioxidant and antibacterial propertiese was developed by blending peony leaf extract (PLE) into chitosan (CS) film through the solution casting method. The physical properties and biological activities of a series of films, including CS film and CS-PLEs incorporated with different concentrations of PLE, were studied by appropriate experimental protocols. The results demonstrated that addition of PLE improved thermal stability, the barrier performance of UV-A and total phenolic content of CS film, and the antioxidant activities of CS-PLEs increased by 60.6 % ~ 73.2 % with the appending proportion of PLE from 0.1 wt% ~ 0.7 wt% compared to CS film. Furthermore, CS-PLEs had better inhibiting effect on bacteria. Notably, CS-PLE (0.7 wt%) wrapping apples showed the least degree of browning among all the groups. Hence, the study of CS-PLEs can provide a new strategy for the preparation of food packaging materials that are green alternatives and reduce environmental pollution.