The products from digestion are released at the apical membrane and diffuse into the enterocyte. Pancreatic lipase, phospholipase A2 and cholesterol ester hydrolase (3 major enzymes involved in lipid digestion) hydrolyse the micelles, breaking them down into fatty acids, monoglycerides, cholesterol and lysolecithin. Here, bile aids digestion by emulsifying the fat goblets into smaller chunks, called micelles, which have a much larger surface area. The remainder of the lipids are digested in the small intestine. Their digestion is started by lingual and gastric lipases, but this only digests 10% of ingested lipids. Lipids are hydrophobic, and thus are poorly soluble in the aqueous environment of the digestive tract. Fructose enters the cell by facilitated diffusion via GLUT5 and is transported into the blood via GLUT2 receptors. Both glucose and galactose exit the cell via GLUT2 receptors across the basolateral membrane into the blood. Glucose and galactose are absorbed across the apical membrane by secondary active transport (along with Na +) through the Sodium-Glucose cotransporter ( SGLT1). Brush border enzymes (lactase, sucrase, trehalase) hydrolyse these compounds into molecules of glucose, galactose and fructose. The disaccharides produced (maltose, maltotriose, and α-dextrins) are all converted to glucose by brush border enzymes.ĭisaccharides occurring naturally in food do not require amylase to break them down.

The main enzyme is pancreatic amylase, which yields disaccharides from starch by digesting the alpha 1-4 glycosidic bonds. The majority of carbohydrate digestion occurs in the small intestine. There are three carbohydrate products which are absorbed by the small intestine glucose, galactose and fructose.ĭigestion of starch is initiated in the mouth, facilitated by salivary amylase.

Are carbs digested in the stomach