ABSTRACT
Dairy foods span the entire range from powdered solids through viscoelastic gels to emulsions and liquid dispersions. This chapter is concerned with fluid milk, the liquid milk as secreted by the cow. The major constituent of cow’s milk is water; the remainder consists largely of lipids, proteins, and carbohydrates synthesized within the mammary gland. Also present are mineral components and some water-soluble and lipid-soluble materials transferred directly from blood plasma, specific blood proteins, traces of enzymes, and intermediates of milk component synthesis. Central to any discussion of milk as a colloidal dispersion is the nature of the micellar interaction potential. In the classical Deryaguin-Landau-Verwey-Overbeek theory of colloidal stability, dispersion stability is ensured when electrostatic repulsion contributions dominate over van der Waals attraction in the interaction free energy equation. The viscosity of milk shows no appreciable difference from Newtonian behavior and a value perhaps one-third greater than that of water.
