Particle size and fat encapsulation define the colloidal dispersibility and reconstitution of growing-up milk powder

Abstract Growing-up milk (GM) powders of contrasting colloidal behavior in aqueous suspension were studied by laser diffraction under wet and dry conditions. The reconstitution of the GM powders considered the interdependencies between particle size and the presence of encapsulated fat. A low dispersibility of a GM powder was associated with the association of fines with large particles. By contrast, the colloidal stability of highly dispersible GM powder resulted from the encapsulation of fat in the fine particles. Together with complementary thermal (differential scanning calorimetry), spectroscopic (Fourier transform scan analysis) and morphological (scanning electron microscopy) analyses, we find that the reconstitution ability, as measured by a dispersibility parameter (% D), strongly correlates with the presence of unencapsulated or free fat.