Physical stability of spray-dried milk fat emulsion as affected by emulsifiers and processing conditions

The effects of emulsifiers, wall, carbohydrate, and processing conditions on the physical properties of encapsulated powders were studied. Unstable emulsion causes an increase in the surface fat of spray-dried powder. Surface fat decreased with increasing DE and was unaffected by drying outlet temperature. A seven-fold decrease in surface fat was observed when the off droplet size increased from 0.5 to 1.2 mum. At best, about 98% of the milk fat was encapsulated. Powder average particle size changed with outlet air temperature, oil droplet size, and DE. Particles contained air cells with some large voids and more spherical shape for 36 DE but dented and irregular shape for 10 DE.