Black pepper essential oil nanoemulsions formulation using EPI and PIT methods

In this study, black pepper essential oil nanoemulsions formulated using low-energy methods (emulsion phase inversion and phase inversion temperature) were compared. In both the methods, optimum components' concentration was 10% of essential oil, 20% of Tween 80, and 70% of distilled water. All nanoemulsions were unchanged after centrifuging at 825 or 1,467 g for 10 min and were more stable when kept at 30°C. Phase inversion temperature nanoemulsions quickly increased droplet size and polydispersity index after 2 weeks, then separated, and created creaming layer on the top after 4 weeks while emulsion phase inversion nanoemulsions were still homogeneous for 4 weeks. However, phase inversion temperature nanoemulsions were more stable than emulsion phase inversion nanoemulsions during heating–cooling cycles. In addition, the loading efficiency of emulsion phase inversion samples was also higher than phase inversion temperature samples, 92.13% and 81.52%, respectively. Practical applications Black pepper essential oil such as other plant essential oils has proved their bioactivity of antimicrobial, antioxidant. Therefore, utilization of essential oil in food industry has set a new trend as a natural food additive. However, essential oils are not easy to add into food products due to the presence of hydrophobic and volatile components. Nanoemulsion is expected to be one of suitable systems for dispersing essential oil in food environment. Essential oil nanoemulsion made from black pepper, very popular spice all over the world, has potential for using as a food preservative for not only many food techniques, but also many kinds of food: dripping fresh food material, spraying on food material, using as seasoning for canning food, or other processing food. Novelty impact statement In this study, Vietnamese black pepper (Piper nigrum) essential oil nanoemulsions were successfully formulated using the phase inversion temperature (PIT) method. Both the emulsion phase inversion (EPI) and PIT methods formed small droplet of 32.4 and 82.4 nm, respectively. However, EPI nanoemulsions were not only more homogeneous, but also more steady than PIT nanoemulsions in our experiment condition.