emulsify

In biology, to disperse fat as millions of microscopic globules suspended in water. Emulsification is an important stage prior to digestion of fat in the human gut.

Fat is an important food, but it has to be digested to produce molecules small enough to be absorbed into the body. The enzyme that does this is soluble in water, but the fat itself is not soluble in water. To bring the fat molecules near to the dissolved enzyme, the fat has to be dispersed into millions of tiny globules. The enzyme works on the surfaces of these globules and fat is digested relatively quickly. Chemicals in bile, produced by the liver, coat the fat and emulsify it. These chemicals act rather like a detergent with one part of the molecule dissolving in the fat and the other dissolving in water.