On the Formation of the Particle Surface Composition during Spray Drying of Milk Powder

Millions of tons of whole milk, skim milk and infant formula are yearly processed into powder form. A common challenge for the dairy industry is, however, that milk fat accumulates at the powder surface during spray drying, leading to reduced storage stability and solubility. This thesis studied which physical mechanism is responsible for the formation of surface fat and how this can be inhibited for more desirable powder properties. The surface fat was identified to be formed during disintegration of the milk emulsions into droplets, and the amount of surface fat was reduced by emulsion stabilization prior to spray drying.