A study reported in Food Research International suggests that microparticulated whey protein (MWP) could be used as a replacement for fat in reduced calorie sauces and dressings.

The researchers from University of Massachusetts, examined the influence of solution composition (pH and salt) and processing (homogenization and heating) on the properties of MWP (0-20%) suspensions. Amongst the findings were that high-pressure homogenisation (6000 psi, 1 pass) of MWP suspensions significantly reduced protein particle size and improved the stability to sedimentation. The lightness and viscosity of the suspensions increased with MWP concentration, which was attributed to the influence of the protein particles on light scattering and fluid flow. Thermal treatment (90°C for 5 min) of MWP suspensions increased their viscosity, which was attributed to aggregation of the protein particles induced by thermal denaturation. Such large aggregates formed after heating proved to be highly unstable to sedimentation, and this would limit their use in low viscosity food and beverage products.

The researchers report that addition of calcium chloride (10 mM) to these heated systems did not cause significant changes in suspension rheology, and this is assumed to be due to the existing denaturation of the MWP. The electrical characteristics of the MWPs were similar to those of protein-coated fat droplets, going from positive at low pH to negative at high pH.

Overall, this study highlights conditions where MWP can be used as a fat mimetic in low calorie food emulsions such as sauces, dressings, and desserts.