Pomegranate seed oil nanoemulsion enriched by alpha-tocopherol; the effect of environmental stresses and long-term storage on its physicochemical properties and oxidation stability

Abstract

In this study, pomegranate seed oil (PSO) nanoemulsions loading different amounts of alpha-tocopherol (0-40) were produced. The nanoemulsions were fabricated by ultra-sonication method and the influence of thermal treatment (20-90 degrees C), pH (2-8) and ionic strength (0-500 mM NaCl) were investigated on physicochemical properties of all treatments. Moreover, the oxidative stability and alpha-tocopherol degradation were also assessed on optimal enriched nanoemulsion formulation during 50-day storage. The droplet diameter, viscosity, antioxidant activity, encapsulation efficiency and loading capacity of optimal formulation were 37.5 nm, 514 cp, 92, 3.45 and 92.5, respectively. The peroxide value changed in the range of 4.5-5.3 and 6.7-10.5 meq O-2/kg in loaded and unloaded nanoemulsions, respectively. Transmission electron microscopy demonstrated spherical morphology of nanoemulsion droplets with diameter average of 40 nm. This study suggested that PSO nanoemulsion loading alpha-tocopheml could be introduced as delivery system with favorable features under severe environmental conditions.