Milk Lipids | Milk Fat Globule Membrane

Abstract

The cellular formation and composition of the milk fat globule membrane (MFGM) begin when milk lipid droplets acquire the MFGM during their assembly and secretion from mammary epithelial cells during lactation. Elements of the MFGM may be derived from the endoplasmic reticulum, other intracellular organelles, the cytoplasm, and the apical plasma membrane. The secreted membrane has a tri-layer of phospholipids consisting of an inner layer that also contains proteins, which is in direct contact with the triglyceride globule core; an interstitial protein coat, and an outer phospholipid bilayer with an associated glycocalyx. Major lipid components of the MFGM include a complex mixture of polar lipids (i.e., phospholipids, sphingolipids and gangliosides) and neutral lipids, as well as sterols and liposoluble vitamins. Around six hundred different proteins have been identified in bovine MFGM and 1100 in human MFGM, including eight that are relatively the most abundant, namely, the mucins MUC-1 and MUC-15, the redox enzyme xanthine oxidoreductase, CD36, Butyrophilin,PAS 6/7 (lactadherin), adipophilin, and fatty acid-binding protein. Research to this date, indicates that the MFGM, with its intricate composition and structure; exerts important bioactivities that potentially improve aspects of human health, such as intestinal, neuronal and immune well-being.