Antibacterial Activity of Black Pepper Essential Oil Nanoemulsion Formulated by Emulsion Phase Inversion Method

Black pepper essential oil has been proved to inhibitthe growth of microorganisms in many recent studies. However, free essential oils are often lipophilic and difficult to use in food products. The nanoemulsion has some advantages such as good dispersion, long-termstability, and transparency. In our study, the Emulsion Phase Inversion method was utilized to formulate black pepper essential oil nanoemulsion. After 6 months, the nanoemulsion retained the droplet size about 18 nm and there was a rise in polydispersity index from 0.087 to 0.608. Besides, concentrations of important components (alpha-pinene, beta-pinene, D-limonene, 3-carene, and beta-caryophyllene) in the BPEO phase of nanoemulsion were similar to pure essential oil. This study was also showed that Escherichia coli and Salmonella entericawere sensitive to black pepper essential oil nanoemulsion than free essential oil. Minimal Inhibitory Concentrations of nanoemulsion for E. coli and S. entetica (137 and 273 mu g/mL, respectively) were higher than those of free essential oil (547 mu g/mL). In addition, nanoemulsion inhibited these bacterial growth on pork samples. When utilizing nanoemulsion as a meat preservative, meat samples, which contained nanoemulsions, observed significantly lower aerobic microbial counts than control samples.