Food Chemistry and Fish in Nutrition

4.1.2.Digestion

The digestion of triglycerides begins in the small intestine. In this region the zymogen, prolipase is secreted by the pancreas (Fig.1). There it is converted into lipase, which in the presence of bile salts and a special protein called colipase, binds to droplets of triglycerides and catalyzes the hydrolytic removal of one or both of the outer fatty acid residues. Monoglycerides remain unhydrolyzed. The fatty acids and the uncleaved gycerides are emulsified into fine droplet by peristalsis, the churning action of the intestine, aided by the detergent effect of the bile salts and the monoglycerides, which are amphipathic molecules. Phospholipids are split by phospholipases to the acyl chains, glycerol and choline. Cholesterol esters are converted to cholesterol and free fatty acids.