How are fats digested?
In the small intestine, bile salts (exist in the bile that is secreted by the liver and temporarily stored in the gall bladder)emulsify fats. The bile salts lower the surface tension of the fats, that is, they reduce the attractive forces between the fat molecules. This causes the fats to break into tiny fat droplets suspended in water, forming an emulsion. Note that this is only a physical break-up of the fats; no chemical break-up of the fats has occurred yet. Emulsification increases the surface area to volume ratio of the fats, speeding up their digestions by lipase (both pancreatic lipase and intestinal lipase) to fatty acids and glycerol.
