The Effects of Main Formulation and Process Parameters on Characteristics of Frankincense Essential Oil Microemulsions

The frankincense essential oil was successfully incorporated into nano-sized microemulsions systems through low energy self-emulsification technique. The effects of main formulation parameters, namely, surfactant, co-surfactant, essential oil, and water concentrations, as well as the mixing rate and temperature on mean particle size, polydispersity (PDI), turbidity and antioxidant activities of colloidal frankincense essential oil nanoparticles, were investigated. The results show that all studied independent parameters affect the most characteristics of frankincense essential oil microemulsions, significantly. The antibacterial activities of essential oils were also considerably increased as incorporated into nano-sized microemulsions. It resulted that the most desired frankincense essential oil microemulsions, with desired characteristics (less particle size, size distribution, turbidity, and greater antioxidant activity) could be obtained using high concentrations of surfactant (0.7 g), medium concentrations of co-surfactant, essential oil and water (0.2 g, 0.1 g, and 9.2 mL, respectively), and medium levels of mixing rate and temperature (500 rpm and 40 °C). Thus, by tuning the formulation or process parameters the most desired nano-sized essential oils can be prepared as natural preservers or health-promoting agents for various food and beverage applications.