Structure improvement of milk powder for chocolate processing

A mechanical–thermal treatment was applied to improve processing suitability of spray-dried milk powders for milk chocolate manufacture. Skimmed and whole milk powder were treated in a twin-screw extruder at 75 °C. A die was not installed to avoid compacting of powder. Results of sorption tests confirmed that the amorphous lactose in the powders was re-crystallized due to this treatment. Powder particles possessed a higher density and fragments refined to the final particle size during chocolate manufacturing immobilized less fat on their surfaces. Milk chocolate made from these powders exhibited lower viscosity and yield value compared with chocolate made with corresponding untreated powders.