Final answer:
The salivary α-amylase enzyme is responsible for initiating carbohydrate digestion in the mouth by breaking down starch into smaller molecules like dextrins, maltose, and glucose.
Step-by-step explanation:
The principle enzyme that begins carbohydrate digestion is salivary α-amylase, also known as salivary amylase. This enzyme is secreted by the salivary glands in the mouth and initiates the breakdown of carbohydrates by attacking the α-glycosidic linkages in starch, which is the predominant carbohydrate consumed by humans. As a result, a mixture of dextrins, maltose, and glucose is produced. Although salivary α-amylase continues to act on the chewed food as it passes through the esophagus, its activity is halted in the stomach due to the acidic gastric juices.
The digestion process resumes in the small intestine where pancreatic amylase, secreted by the pancreas, further breaks down the carbohydrates. The breakdown products eventually include monosaccharides like glucose, fructose, and galactose, which are readily absorbed into the bloodstream through the intestinal walls.