Digestion in the Buccal Cavity

Both mechanical and chemical digestion begin in the mouth. Mastication (chewing), carried out with the teeth and tongue, crushes and grinds the food — the teeth crush and grind while the tongue manipulates the food, which becomes moistened by saliva, making crushing easier. The mucus in saliva lubricates the food and binds the food particles into a rounded mass called a bolus. This bolus is swallowed by deglutition: the tongue presses against the palate and pushes the bolus into the pharynx, from where it passes into the oesophagus.

Chemically, the only digestion that occurs in the mouth is carried out by salivary amylase, which converts starch into maltose:

Salivary amylase: Starch (polysaccharide) -> Maltose (disaccharide), at pH 6.8

About 30% of the starch in a meal is converted to maltose while still in the mouth. Although food itself remains in the mouth only briefly, the action of salivary amylase actually continues for a further 15-30 minutes, until gastric juice mixes thoroughly with the food in the stomach and stops it. …