Role of Milk Fat in Dairy Products

Milk contains approximately 3.5% (w/v) fat. Since the manufacture of many dairy products involves removal of moisture, or in some other way concentration of the lipid fraction, milk fat is often a major component of dairy products. This chapter discusses the role of milk fat in butter and related spreads, cream products, cheese, ice cream, ingredient powders, infant milk formulae and milk chocolate. Milk fat gives butter its structure in the form of a three-dimensional network of fat crystals and also contributes to its flavour. Cream is a fluid milk product comparatively rich in fat, and the contribution of fat to cream is important for its mouthfeel and flavour. The significance of milk fat in different cream products is based on their fat content, fat distribution, the physical state of the fat and the chemical, physical and sensory properties of the non-fat ingredients. Cheese is essentially a concentrated protein gel containing fat globules which act as points of weakness in the gel matrix, and thus milk fat contributes to the texture of the product in addition to contributing to flavour, colour and functional behaviour. Fat and fat structure development in ice cream and related frozen dairy desserts are critical to its optimal structure and physical properties, stability, flavour and texture. In the case of ingredient powders, lipid levels can vary greatly depending on the type of dairy powder and the procedures involved in their processing. The role of milk fat in various dairy powders is discussed, with a particular focus on those with functional properties affected markedly by surface fat. Infant milk formula is a highly specialized powder with specific nutritional requirements for the neonate, and much work has been done in recent years to structure triacylglycerols to make the fat components mimic those of human milk. Chocolate is a complex suspension of cocoa solids, sugar crystals and milk powder, and milk fat influences its flavour, texture and quality.