Polydopamine-immobilized lysozyme for the fabrication of antibacterial films and its application in the preservation of fresh pork

Immobilized antibacterial packaging provides a long-term fresh-keeping effect for food. This study prepared a novel antimicrobial active packaging film by grafting lysozyme with polydopamine (PDA). XPS, ATR-FTIR, and SEM confirmed that PDA and lysozyme were immobilized on PE film. The mechanism may be that PDA (rich in catechol and quinone groups) undergo amide and Schiff base reactions with lysozyme. The modified film's barrier properties (UV, water vapor, oxygen transmittance) and antibacterial function significantly improved. Afterward, the pork was packed with the films (4 °C, 10 d) and monitored for freshness. The films significantly reduced the total viable count and total volatile basic nitrogen of pork and increased the shelf life by 3 days. In summary, this novel immobilized technique can be applied effectively for film modification and enhancing food preservation performance.