Manufacture and application of high milk protein powder

A procedure was developed for the production of a high milk protein powder that was rich in both milk proteins, casein and whey proteins, and free of lactose. The method utilized ultrafiltration and diafiltration with no pH adjustment and a relatively low temperature. Spray drying was conducted at lowtemperatures (120 to 125degreesC inlet air temperature, 75 to 80degreesC outlet air temperature). The resulting powder contained at least 84% total protein (casein and whey proteins). Microstructural studies of the high protein powders revealed that the surface structure of the powders became smoother as lactose was reduced. The surface of the powders with the most lactose, such as skim milk powder, had the most wrinkles. The virtual absence of lactose in this powder allows storage at room temperature for a long time without deterioration or caking. Solubility index of the powder decreased (solubility increased) as temperature of reconstitution increased from 25 to 60degreesC. Foaming capacity was highest at pH 10. Because of the similarity of the proteins of this powder to those of skim milk, and due to the absence of lactose, it was possible to use it in the manufacture of nonfat yogurts with good body and texture. Traditionally, nonfat yogurts have poor body and frequently have excessive whey separation. Use of gelling and stabilizing agents is therefore almost mandatory. The high milk protein powder, while adding protein to yogurt, served as a stabilizer to improve body and texture. The suitability of this powder as a medium for bulk starter was also investigated. The high buffering capacity of this powder in combination with nonfat dry milk made possible the production of an active bulk starter, which was subsequently used in the manufacture of Gouda cheese.