Final answer:
Starch digestion begins in the mouth with salivary α-amylase breaking down α-glycosidic linkages into simpler carbohydrates. It continues in the small intestine with pancreatic amylase until it is reduced to monosaccharides like glucose.
Step-by-step explanation:
Partial digestion of starch begins in the oral cavity through the action of salivary α-amylase. This enzyme attacks the α-glycosidic linkages in starch, which is the main carbohydrate consumed by humans, and starts breaking it down into simpler carbohydrates such as dextrins, maltose, and glucose. As the food is chewed and mixed with saliva, the enzyme remains active even as the food passes through the esophagus; however, it is rapidly inactivated by the acidic environment in the stomach.
The chemical digestion of starches continues in the small intestine, where pancreatic amylase plays a significant role. The digestion process reduces the polysaccharides into shorter chains and eventually into monosaccharides like glucose that can be absorbed by the small intestine.
It's important to note that saliva not only provides the enzyme for starch digestion but also mucous for lubrication, making it easier for the bolus to travel down to the stomach.