Digestion of carbohydrates − mouth and small intestine
Digestion of fats − small intestine
Digestion of proteins − stomach and small intestine
Digestion of carbohydrates: Starch is digested in the mouth by salivary amylase. Other forms of carbohydrates are digested in the small intestine.
Starch + Salivary Amylase → Sucrose
Maltose + Maltase → Glucose
Lactose + Lactase → Glucose + Galactose
Digestion of Proteins: Partial digestion of protein takes place in the stomach by gastric enzyme pepsin. Further digestion of protein happens in the small intestine.
Protein + Pepsin → Peptone + Proteose
(Protein + Peptone + Proteose) + (trypsin + chymotrypsin) → Dipeptides
Digestion of Fat: Fat is at first emulsified by bile and then its digestion happens in the small intestine.
Fat + Lipase → Fatty acids + Glycerol