Morphometry and textural surface properties of heat induced whey protein microparticles

The present work focuses on the study of four key factors controlling the process of whey protein microparticulation: protein suspension concentration (%WPI 2.5 % vs. 5.0 %); medium acidity (pH 4.5 vs. 5.5); denaturation temperature (80◦C vs. 90◦C); and particle size reduction method (180 bar x 1, 2 or 3 cycle(s); 1800 bar x 1 cycle). The effects of the microparticulation process were studied by analysing the degree of protein aggregation, morphometry, and surface textural characteristics of the microparticles. The results obtained indicate that the most favourable treatments to achieve a higher proportion of particles within the optimal range required by the food industry (1–10 μm) can be obtained by gentle protein denaturation (80◦C) using a medium with a pH lower than the isoelectric point of β-lactoglobulin and moderate concentrations of whey protein (2.5–5.0 %). Under these premises, it is necessary to use a high intensity particle size reduction method (1800 bar) to achieve the average diameter and the adequate homogeneity in a consistent fashion.