5 - Milk and Dairy Polar Lipids: Occurrence, Purification, and Nutritional and Technological Properties

Abstract

Cow's milk contains 12.8–40 mg/L of total Polar Lipids (PLs), which is equivalent to 0.32–1.0% of the total lipids of milk. A major part of PLs in milk is the membrane surrounding fat globules, which is called the Milk Fat Globule Membrane (MFGM). In the dairy industry, processing techniques, such as churning cream into butter or homogenizing (phase conversion) the concentrated cream into butter oil break the fat globules and the resulting MFGM fragments are preferentially distributed to aqueous phases, such as buttermilk and butter serum. Technologies are available for isolation of MFGM fragments and for further purification to obtain PL concentrate from the byproducts. Recently, milk PLs have gained attention because of the beneficial health properties they possess. In addition, PLs are amphiphilic molecules that can be used as emulsifiers for food product development. This chapter discusses the occurrence, composition, and factors influencing composition of PLs in milk, explains the distribution of MFGM and PLs during dairy processing, and this helps determine which processing-derived streams/fractions can serve as a good sources for isolation of MFGM and purification of PLs. It also presents isolation and purification techniques, reviews nutraceutical and technological properties of PLs, and discusses the possible applications of MFGM material and PL concentrate. The chapter elucidates the possibilities of obtaining MFGM material and PL concentrate from dairy processing–derived streams and the potential uses of such ingredients for development of functional foods and nutraceuticals.