Protein Hydration and Viscosity of Dairy Fluids

Abstract

The rheological properties of milk, dairy products, dairy process streams and food ingredients derived from milk are important for the efficient processing of dairy products, as well as yielding products with desirable properties. For protein-rich dairy powders, it is generally more economic to process concentrated streams. Consequently, knowledge of the factors that affect their viscosity and performance as ingredients is important. The viscosity of concentrated solutions can be very sensitive to relatively minor alterations to any protein interactions, such as the degree of aggregation or altering the ratio of whey protein to casein, within the protein phase of the mixture. Many of the observed effects can be traced back to the fundamental properties of the particular proteins involved and follow well-known physical principles. In each section of this chapter, the fundamental aspects of the behaviour of the relevant milk proteins are outlined, followed by a brief consideration of the interactions (including processing-induced interactions) and concluding with a more detailed review of the known characteristics of a range of milk protein product solutions.