Chitosan/alginate dialdehyde trilayer films with cinnamaldehyde nanoemulsions for grass carp preservation

Chitosan (CS) cross-linked films were prepared using the Maillard reaction (CMR). Layer-by-layer casting created additional layers using alginate dialdehyde (ADA) containing cinnamaldehyde nanoemulsions (CANE) and CS. The ability to preserve grass carp fillets was evaluated along with the effects of CANE concentration on the microstructure, physicochemical properties, controlled-release behavior, antioxidation, and antibacterial activities of the films. In all films, Schiff base-induced bonds, electrostatic interactions, and hydrogen bonds brought the layers closer together, improving the mechanical properties (e.g., a 70% increase in tensile strength and a 34% increase in breaking elongation) and barrier capacity (e.g., inhibiting ultraviolet, water vapor, and oxygen transmission). CANE can improve the antioxidant activity, antibacterial activity, and sustained release characteristics of films. More importantly, over the 8-day storage period, the fish packaged using the active films were better than those in the control, commercial PE, and CS films in terms of thiobarbituric acid reactive substances, pH, texture, total viable counts, and volatile basic nitrogen with indicator species. Fish could have a prolonged shelf life due to the prepared CMR/ADA-CA/CS film. In other words, it may be used as a sustainable food packaging material, with the performance of the film being regulated by different CANE concentrations.