Fat globule membrane
Milk fat - Composition, organization and properties

Each fat globule is surrounded by a very thin protective layer, usually called the globular membrane. Without the presence of this membrane, the existence of the globules would be impossible, as the oil micro-droplets would have coalesced through a process of coalescence. The study of the membrane is very important in explaining many technological problems, as all interactions between fat globules and plasma take place through it. The physical stability of fat globules depends largely on the properties of the membrane.