A process for increasing the free fat content of spray-dried whole milk powder

Exposing spray-dried whole milk powder to high shear and elevated temperature in a twin-screw continuous mixer increased the free fat content. The effects of operating conditions (powder feed rate, processor screw speed, and process temperature) on lactose crystallinity, particle size distribution, color, and moisture content of spray-dried whole milk powder were investigated using response surface methodology. Exposure to elevated temperatures and high shear: (a) increased the free fat to more than 80%, (b) crystallized the lactose, (c) reduced the average volume-based particle size, and (d) broadened the particle size distribution. The raw whole milk powder with creamy-white color turned into an oily paste with bright-yellow color. Processing enhanced the functional properties of spray-dried whole milk powder for milk chocolate manufacture.