Self-assembly technology engineering multi-functional slow-release packaging system with self-starting program for prolonged preservation of perishable products

The inadequacies in the release kinetics of extant active packaging films and coatings present formidable challenges in addressing issues pertaining to food waste and food safety, particularly in the context of microbial infections that occur during the storage and transportation of food. In response to this pressing challenge, this work pioneered an innovative multifunctional packaging system, distinguished by its autonomous and sustained release properties, denoted as TA/CA-CS films. This innovative system is constructed through the self-assembly of acid-sensitive tannin-cinnamaldehyde multifunctional fillers (TA/CA) in conjunction with a judicious selection of a weakly acidic chitosan (CS) film substrate, endowed with an intrinsic “built-in initiator”. Given that the weak acidity of the CS film can trigger the reverse disassembly of TA/CA by destroying the dynamic C–O bonds that serve as bridges inside TA/CA, the TA/CA-CS film achieved the controlled and slow release of active substances. The TA/CA-CS films preserved the intended functionalities of both TA and CA components throughout the assembly-disassembly process, thereby manifesting enhanced antibacterial, antifungal, and antioxidant properties. Notably, the DPPH· and ABTS· + scavenging rate of the TA/CA 0.3 -CS film surpassed 89.7%, and its efficacy in eliminating bacteria and fungi exceeded 99.9%. Consequently, the TA/CA 0.3 -CS film exhibited exemplary preservation capabilities, significantly prolonging the shelf life of citrus by approximately 1.9 times. Furthermore, the augmented mechanical strength, heightened barrier properties, and demonstrated safety profile laid a robust foundation for its practical deployment. The gratifying attributes of the TA/CA 0.3 -CS film underscore its suitability for the efficient preservation of perishable products.