Physical and functional properties of whole milk powders prepared from concentrate partially acidified with CO2 at two temperatures

Effects of carbonation of whole milk concentrate on spray dried powder properties were investigated. Concentrate acidification by CO2 addition (2000 ppm) was found to strongly modify the functional properties (solubility, dispersibility) and structural/physical properties (porosity, free fat) of the resulting powders. For concentrates treated at low temperature (where the majority of emulsified fat is in a solid state at 4 °C), colloidal calcium phosphate (CCP) release, casein dissociation and fat coalescence were observed. For warm CO2 treated concentrates (30 °C) only CCP release was observed. The best functional properties (higher solubility and dispersibility) were found for powders produced from the warm treated concentrates, which were possibly due to the high porosity and better fat globule preservation.