Final answer:
The enzyme responsible for breaking down starch into disaccharides and trisaccharides is amylase. It begins the digestion of carbohydrates in the mouth and continues in the small intestine.
Step-by-step explanation:
The enzyme that digests starch into disaccharides and trisaccharides is amylase. Amylase is involved in the digestion of carbohydrates and starts its action in the mouth, where it is present in saliva. In the small intestine, pancreatic amylase continues the breakdown of starch into maltose, which is a disaccharide. Other enzymes such as maltase, sucrase, and lactase subsequently break down disaccharides into monosaccharides, which can be absorbed by the body.