Use of whey protein ingredients to produce milk fat simulants

The article deals with the problem of thermomechanical processing conditions influence on the properties of dry whey protein ingredient solutions: whey protein concentrates and isolates. The initial stage of obtaining fat property mimics is heat treatment of protein solutions to the temperature exceeding the denaturation threshold (65-75 °C). The next mechanical impact on the aggregates obtained leads to the formation of the particles similar to the fat globules. Protein mass fraction has a significant influence on the denaturation process. When its value becomes larger, the number of collisions between primary aggregates increases as well as the coagulation probability. In isolate solutions the denaturation rate was high, and it was observed intensive, irreversible coagulation at all protein concentrations. Aggregates were characterized as porous, branched, and polydisperse. Shear rate increase under mechanical impact resulted in even greater aggregates growth. Samples obtained at high shear rates were characterized by apparent physical instability. Large size of the protein aggregates was confirmed by a high degree of sedimentation. Suspensions were characterized as granular. The denaturation rate and coagulation intensity were lower in concentrate solutions. Presence of lactose helped to protect proteins from rapid loss of solubility by stabilizing their structure against thermal unfolding. The aggregates were characterized by a round compact shape, and the particle size didn’t differ a lot. Protein mass fraction change of the concentrate suspension samples did not have significant influence on the aggregates size and shape. Rotor rotation speed increase contributed to the particle size decrease. The solutions were characterized by the sedimentation stability and they had a uniform thick consistency imitating properties of the fat-containing products.