Effect of Medium-High Energy Emulsification Condition on Physicochemical Properties of β-Sitosterol Multiple Emulsion

Phytosterols are used to lower the blood cholesterol. beta-Sitosterol is one of the most important phytosterols with very poor water solubility and bioaccessibility. The main goal of the current research was to investigate the effects of different emulsification variables (i.e. shear, time, pressure and cycle) on the physicochemical properties, release behaviour and encapsulation efficiency of beta-sitosterol in water-in-oil-in water (W/O/W) emulsion. Initially, 19 beta-sitosterol emulsions were prepared under different experimental conditions (shear 3000 and 6000 rpm; time 2.5 and 5 min; pressure 100, 200 and 300 bar; cycle 1-3). In this study, the beta-sitosterol emulsion prepared at 6000 rpm, 5 min, 300 bar and 3 cycles had the smallest average droplet size (139 nm) among all prepared samples. The interaction between shear and time showed the most significant (P < 0.05) effect on the polydispersity index (PDI) and turbidity of the beta-sitosterol emulsion. Increasing homogenization pressure and cycle led to improving emulsion stability and encapsulation efficiency. The beta-sitosterol emulsion homogenised at 100 bar for 1 cycle had the highest encapsulation efficiency (81.7%) among all samples. The optimization study showed that the emulsification at 300 bar for 3 cycles resulted in the most desirable beta-sitosterol emulsion.