Digestion of Fats

Digestion of Fats:

Stomach:

Lipase present in the stomach is unable to hydrolyze fats owing to the high acidity of the gastric contents. Therefore, the major part of the ingested fat is digested in the small intestine.

Small Intestine:

The ingested fat reaching the duodenum is mixed with the bile and pancreatic juice which contains lipase. The bile salts emulsify the fat before the action of lipase. The emulsification is also brought about by monoglycerides, phos­pholipid and lysolecithin.

The secreted inactive pancreatic lipase is acti­vated by bile and Ca. The surface area of the emul­sified fat becomes increased for which the rate of reaction of lipase is increased. Pancreatic lipase hydrolyzes 1- and 3-positions of the triglycerides leaving a mixture of 2- monoglycerides, 1, 2- and 2, 3-diglycerides as well as the soaps of the free fatty acids.

The pancreatic juice also contains phospholipase and cholesterol-esterase which hydrolyze phospholipid and esterified cholesterol. Intestinal juice also contains a lipase whose action is not of much importance as most of the fat is hydrolyzed by the pancreatic lipase.