Effect of Emulsifier Type and Disruption Chamber Geometry on the Fabrication of Food Nanoemulsions by High Pressure Homogenization

Production of food nanoemulsions by high pressure homogenization (HPH) is investigated, focusing on the effect on droplet nanonization of emulsifier type and concentration, as well as of the geometry of the homogenization chamber. Several food-grade emulsifiers were characterized, in comparison with artificial ones, in terms of their interfacial and dynamic properties, by pendant drop measurements. The kinetics of the emulsification process was determined by dynamic light scattering measurements on the emulsions produced at different pressure levels (70-280 MPa) and number of HPH passes, in four different homogenization chamber geometries. The results show that the kinetic parameters of the emulsification process can be primarily correlated with the interfacial and dynamic properties of the emulsifiers, while the fluid-dynamics regime establishing in the homogenization chamber contributes only to a lesser extent. Nevertheless, the correct design of the homogenization chamber may help in obtaining uniform fluid-dynamic conditions, which ensure a narrow droplet size distribution.