Final answer:
The digestion of carbohydrates begins in the mouth with the enzyme salivary amylase. Chewing breaks down the food into smaller pieces, allowing it to be swallowed as a bolus. The acidic stomach environment then stops the action of salivary amylase.
Step-by-step explanation:
Digestion of carbohydrates begins in the mouth by the action of an enzyme called salivary amylase. This enzyme starts the breakdown of starches, which are complex carbohydrates, into maltose, which is a simpler disaccharide. As you chew, the food is broken down into smaller pieces, increasing its surface area and making the enzyme's job easier. When you swallow, the food, now formed into a bolus, travels through the esophagus. There is no significant digestion of carbohydrates in the esophagus, since it does not produce digestive enzymes, only mucous for lubrication. Upon entering the stomach, the acidic environment halts the activity of salivary amylase, ceasing the carbohydrate digestion that began in the mouth.