Characterization of black pepper essential oil nanoemulsion fabricated by emulsion phase inversion method

Recently, essential oils have been become popular materials in many research on food, drug and cosmetic production. In this study, black pepper essential oil (Piper nigrum L.) was loaded in nanoemulsion by Emulsion Phase Inversion method. For understanding clearly phase behavior of this system, pseudo-ternary phase diagram was constructed and suitable parameters relating to components concentration were found: 10% (v/v) of essential oil and 2.0 surfactant-oil ratio. Besides, the difference in physical characteristics between frozen-thawed nanoemulsion and control nanoemulsion was indicated by thermal analysis, chemical components determination and stabilized test. Especially, the frozen-thawed step (frozen at -15 degrees C for 24 hr then thawed at room temperature) not only remained volatile compounds well, but also improved black pepper essential oil nanoemulsion stabilization during five-week storage. Last but not least, Tween 80 was really reasonable for fabricating the most stable nanoemulsion among four testing Tweens. Novelty impact statement In our work, the EPI process for formulation of black pepper nanoemulsion was studies in order to obtain optimum parameters. The SOR of 2.0 and utilization of Tween 80 as surfactant was proved suitable in forming this system. Especially, a frozen step combined with thawing at room temperature of EPI nanoemulsion not only affected the system characteristics including thermal behavour, chemical components, but also effectively stabilized our nanoemulsion by decreasing both of droplet size and polydispersity index. Therefore, BPEO nanoemulsion could prolong the storage period for application.