Digestion and Absorption of Lipids

What are the sites for Lipid Digestion

Mouth,

Stomach

Small intestine

How is Lipids digested in the mouth

Mechanical Digestion: chewing your foos

Emulsification: Breakdown of large droplets of lipid into tiny droplets

Chemical Digestion

Saliva contains lingual lipase which is a serine protease. It hydrolyses medium and long chained triglycerides

Products are diglycerides, monoglycerides and fatty acids

How is lipid digested in the stomach

2 enzymes act on the stomach: lingual lipase and gastric lipase

They hydrolyze the ester bonds in medium and long chained triglycerides. The products are some diglycerides and fatty acids

How is lipid digested in the small intestine

•Mechanical digestion

•Emulsification continue

•Increase surface area of lipid droplets so enzymes can work at lipid/aqueous interface

•Achieved by

–Peristalsis: mechanical mixing

–Bile salts: secreted by the gall bladder; they has detergent properties

Chemical Digestion:

Pancreas secretes pancreatic lipase and pancreatic col-lipase. The pancreatic lipase binds to the surface of the droplets in the presence of co lipase

The lipase and collapse complex spreads over the surface of the droplet

These enzyme hydrolyses triglycerides into monoacylglycerol and fatty acids= lipid digestion products

What are the other pancreatic enzymes that’s involved in lipid digestion

Cholesterol esterase- hydrolyses cholesterol ester to cholesterol and fatty acids

Phospholipase A2- digests phospholipid to lyse-phospholipid, activated by trypsin

Lysol-phospholipase-

What are the products of fat digestion form into mixed micelles

•Bile salts

•Free fatty acids

•Free cholesterol

•2-monoacylglycerol

•Phospholipid