Comparison of low energy and high energy methods in fabrication of pomegranate seed oil nanoemulsion containing mixed non-ionic surfactants

Pomegranate seed oil (PSO) is an edible oil extracted from industrial wastes of pomegranate processing presented a wide range of biological effects because of its high punicic acid and polyphenolic compounds. Due to its low solubility and high oxidation sensitivity, nanoemulsion (NE)-based delivery systems are recommended to use this oil in the food and beverage industries.  NEs can be fabricated from high-energy or low-energy methods, which each have advantages and limitations. In this study, we compared a high-energy method (sonication) with a low-energy method (spontaneous emulsification) to form PSO NEs based on mixed non-ionic surfactants (Span 80, Tween 80). The effect of surfactant concentration on NE droplet size showed that both methods were able to produce emulsions with ultrafine droplets (d < 150 nm), but the low energy required higher surfactant. Moreover, the effect of various storage temperatures (4, 25 and 55 ºC) on the physical stability of the selected NEs highlighted the stimulated droplets coalescences at higher temperature (55 ºC) leading to relatively unstable NEs in contrast to complete stable ones achieved at mild condition (4 ºC). Furthermore, the oxidative studying (30 days) showed that NE produced by high energy method was significantly (p<0.05) more sensitive compared to similar counterparts formed by low energy method.