Multifunctional packaging film with sustained release behavior triggered by pH microenvironment for efficient preservation of pork

To tackle microbial contamination and spoilage during pork storage, transportation, and sales, a novel packaging film with exogenously driven controlled release behavior was designed through the demand-directed preparation of the emulsion of shellac-encapsulated cinnamaldehyde nano-capsules (SNCs) and the ingenious integration of chitosan (CS) film matrix. Among them, the SNCs were synthesized using the solvent exchange method, allowing controlled release of cinnamaldehyde (CA) in response to volatile alkaline substances present in the meat. The electrostatic interaction between SNCs and CS molecules improved the thermal stability, water resistance, tensile strength, and viscosity of the film-forming solution, while the CA in SNCs enhanced UV resistance and antimicrobial properties of the film. Notably, the CS film with SNC-100 loaded (CSNCs-100 film) achieved 99% inhibition against both E. coli and S. aureus, regulated environmental moisture, and prolonged the freshness duration of pork by an impressive six days.