Fat globules in milk

The milk fat included in the globules is the major native form of milk fat. The milk fat globule is a spherical particle that is the form in which milk fat is secreted in milk. The physical, chemical and technological properties of milk fat globules are influenced by their size.

In milk as secreted by the cow these globules average about 10 microns in diameter, with a range from 0.1 microns to ~15 microns. The globules were significantly higher in the milk with the highest fat content.

Milk fat globule membrane is a delicate structure and can easily be ruptured by either physical or thermal shock. It forms around fat globules as they pass from secretory cells in the cow’s udder into the milk. All interactions between fats and plasma must take place through the membrane.

When the milk fat globule membrane is intact, it protects the fat exposure to naturally occurring lipase enzymes and the resulting development of a rancid off-flavor. T

he density of the milk fat globules is much lower than that of the m ilk serum and as a result, milk fat globules rise at form a fat rich phase, a process commonly called creaming.

In the globule, fatty fractions e.g. sterols, triglycerides that are less soluble in water are found in the interior of the globule.

The lipids of milk fat serve nutritionally as an energy source, act as a solvent for the fat soluble vitamins and supply essential fatty acids.
Fat globules in milk