Dual-enzyme-responsive fibers for chilled mutton preservation

Extracellular enzymes secreted by predominant microorganisms play a crucial role in accelerating meat spoilage. Developing responsive antibacterial packaging that targets these enzymes offers a promising strategy to extend shelf life. In this study, the extracellular enzyme production of typical spoilage and pathogenic bacteria of mutton was confirmed. Building on this, a dual-enzyme-responsive antibacterial pad was fabricated using lipase-responsive polycaprolactone (PCL), protease-responsive zein, and the antibacterial agent cinnamaldehyde (Cin) via electrospinning technology. Results showed that all tested bacteria exhibited extracellular enzyme production under varying temperature (37℃, 4℃) and pH (5.5, 6.0, 6.5) conditions. SEM and FTIR analyses confirmed the successful embedding of Cin through physical interaction. Compared to PCL/Zein, the antibacterial activity of the PCL/Zein@7 %Cin reached 99.9 %, and the antioxidant capacity increased from 18.06 % to 65.55 %. Furthermore, when fibers were exposed to P. aeruginosa extracellular enzymes, which degrade ester and peptide bonds in the substrate, a 57.67 % decrease in thickness occurred within 48 h, accompanied by respective reductions of 24.86 % in tensile strength and 82.16 % in elongation at break. P. aeruginosa secreted enzymes also increased Cin release by 62.5 %. Preservation tests demonstrated that enzyme-triggered fiber degradation released Cin, exerting antibacterial and antioxidant effects that extended chilled mutton shelf life by 6 d. These findings offering a novel approach to tackle the critical issue of the limited shelf life of chilled mutton.