Development of functional, sustainable pullulan-sodium alginate-based films by incorporating essential oil microemulsion for chilled pork preservation

Developing safe, eco-friendly, and functionally edible packaging materials has attracted global attention. Essential oils, can be incorporated into packaging materials as antioxidant and antibacterial agents. However, their high volatility and discontinuous film matrix issues may cause a rough film surface, limiting the application in food packaging. In this study, thyme essential oil microemulsion (TEO-M) was prepared and incorporated into a pullulan-sodium alginate (PS) film. The TEO-M incorporation endowed the PS film with antioxidant and UV protection properties. The antioxidant activities of the TEO-M-incorporated PS film were significantly better than those of the TEO-C (thyme essential oil coarse emulsion)-incorporated PS film. In comparison to TEO-C, the distribution of TEO-M in the film is more uniform. Lipid oxidation and the growth of microorganisms in chilled pork were inhibited by incorporating TEO-M at a concentration of 50 mg/mL in the PS film (PS-50M). After 10 days of storage at 4 °C, the total viable count (TVC) of chilled pork preserved in the PS-50M material was significantly reduced compared to the control group (P < 0.05). This study shows that incorporating TEO-M in the PS film provides a method for applying essential oils in food packaging, which may have great potential in the food industry.