Milk fat microencapsulation using whey proteins

The effects of homogenisation conditions (pressure and number of passes) and emulsion composition (fat, whey protein, lactose, salts and water) on the properties of emulsions and microencapsulated milk fat powders were measured. The emulsions were assessed by fat globule diameter and size stability over time. The properties of the powders measured were particle diameter, reconstituted emulsion fat globule diameter, free fat, surface fat and fat oxidation. As expected, increasing homogenisation pressure reduced the fat globule diameter and increasing the number of homogenisation passes reduced the diameter of the largest globules. Increasing fat and salts reduced fat globule diameter stability after 2 homogenisation passes but the reduction in stability was less after 4 passes. Increasing the lactose : whey protein concentrate ratio reduced free fat and fat globule aggregation after powder reconstitution, but not the surface fat. The higher level of fat increased the surface fat on powder particles and the level of oxidation during storage.