In addition to lubricating food for easier swallowing and to protecting against bacteria entering the mouth with food, saliva contains a large amount of amylase. And then starch and glycogen in your meals are broken into oligosaccharides by amylase . After the oligosaccharides entering the small intestine, they are completely decomposed by amylase, and disaccharidase. Finally, the monosaccharide is absorbed by the small intestine.