Structural stability and antibacterial activity of gelatin/zein composite films loaded with thirteen-spices essential oil for chilled pork preservation

Chilled pork exudate provides a nutrient-rich, high-humidity microenvironment that promotes microbial spoilage. To address this, an antibacterial gelatin/zein (GZ) composite film incorporated with thirteen-spices essential oil (TSEO) was developed by solution casting. The effects of GZ mass ratio and TSEO loading on film properties and preservation efficacy were investigated. The GZ 1:3 film with 1 mL/dL TSEO exhibited optimal performance, showing an elongation at break of 103.08 ± 2.26%, solubility of 52.94 ± 4.09%, volatile mass fraction of 18.21 ± 0.51%, and a TSEO retention rate of 80.39 ± 1.49% during 4 °C storage. Hydrogen bonding and electrostatic interactions between G and Z formed a dense matrix that effectively loaded TSEO, yielding strong antibacterial zones against E. coli and S. aureus (28 ± 1 mm/27 ± 2 mm). This film significantly slowed quality deterioration in chilled pork, maintaining acceptable color, pH, and total viable count for up to 9 days at 4 °C. In conclusion, the optimized 1 mL/dL TSEO loaded GZ 1:3 composite film exhibited enhanced structural stability and sustained antimicrobial activity, thereby extending the shelf life of chilled pork, which contributes to the development of environmentally friendly natural active packaging materials for meat preservation.