Enzyme-responsive core-shell nanofibers based on zein/gelatin with controlled release of carvacrol for salmon preservation.

This study presents an enzyme-gated, core-shell fibrous packaging system engineered for intelligent, on-demand salmon preservation. Utilizing coaxial electrospinning, carvacrol (CAR) was encapsulated within a zein (ZN)/gelatin (GA) matrix with a 63.94% encapsulation efficiency, producing uniform, highly hydrophobic films (water contact angle: 125.2°). The packaging functions as an "intelligent gate," where spoilage-associated bacterial proteases induce proteolytic hydrolysis of the shell, triggering the precise release of the antimicrobial payload. Mechanistically, release kinetics shifted from passive diffusion (Higuchi model) under enzyme-free conditions to an enzyme-catalyzed, first-order process at 3 U/mL protease, enhancing cumulative CAR release from 40.4% to 88.4%. In 4 °C storage trials, this dynamic responsiveness effectively inhibited bacterial proliferation and extended salmon shelf life by 2 days. This approach offers a sophisticated, targeted solution for intelligent food packaging, successfully overcoming the limitations of conventional burst-release systems.