The effect of disperse phase viscosity in the emulsification of a semi-dairy beverage–combining emulsification experiments and numerical single drop breakup simulations

Due to the rise in the demand for semi-dairy beverages (vegetable fat in a de-fatted dairy matrix) as well as for fully plant-based formulations, there is a growing interest in better understanding how emulsification processes are influenced by raw material choices. Semi-dairy beverages, for example, utilize a wide variety of vegetable oils in their formulation. This contribution combines traditional emulsification experiments with high-resolution numerical drop breakup simulations to improve the understanding of how oil viscosity influences the emulsification process. It is concluded that the experimentally observed increase in drop diameter with oil viscosity is well predicted by the viscosity-corrected Kolmogorov Hinze theory. The numerical simulations are able to reproduce this trend and allow further insight into breakup mechanism; suggesting that it is the prolonging of the deformation phase that make more viscous oils more challenging to homogenize. From a beverage processing perspective, the homogenizing pressure (and energy cost) necessary to achieve the same physical stability needs to be 73% higher if using a typical high-viscosity vegetable oil than if using a typical low viscosity vegetable oil.