Whey protein solutions (70 mg mL−1) were subjected to heat and subsequent mechanical treatments at different conditions of temperature (80–90 °C), holding time (0–50 min), pH (4.0–7.0), pressure (10–30 MPa) and number of passes (1–3) through a homogeniser, the resultant products being analysed in terms of particle size [D (v, 0.5)], viscosity (at 100 s−1 shear rate) and aggregation yield. Predicting the final characteristics of the microparticles is of paramount importance to ensure their correct performance in food products. As a result, different microparticulated products, with particle sizes ranging from 1 to 17 µm, viscosities between 4.5 and 65 mPa s and up to 100 % aggregation yield, were produced by taking advantage of the optimisation properties provided by different factorial designs. The reliability of the statistical model was tested, leaDing to acceptable errors, between 4.0 and 27.5 %, for the purposes sought.