The effects of temperature and homogenization pressure on flow characteristics of whey protein-stabilized O/W emulsions

The effects of temperature and homogenization pressure on flow characteristics of whey protein-stabilized oil-in-water emulsions and emulsion stability were investigated. A 6 wt% water solution of the commercial whey protein concentrate (WPC) was mixed with sunflower oil at an oil phase volume concentration of 30%, then homogenized by 2-stage homogenizer at the desired temperature (30, 45, or 60 degrees C) and pressure (30/3, 60/6, or 90/9 MPa). The rheological properties of model emulsions were measured at 30, 45, or 60 degrees C, depending on the homogenization temperature, using a rotational rheometer with a concentric cylinder measurement cell (Rheotest RV). The data obtained fitted a power law model and results were referred to the consistency and flow behavior indices. The temperature and pressure of the homogenization process affected both parameters of the power law model. High correlations were found between emulsion stability and the flow behavior and consistency indices (r=0.87 and r=-0,72, respectively).