Each major nutrient in food has its own dedicated digestive enzyme, and matching salivary amylase to its actual target settles this question.
- Fats: Handled by lipase enzymes, not amylase, since fat molecules and starch molecules have completely different chemical bonds that need different enzymes to break them.
- Vitamins: Absorbed largely as they are, without any enzyme needed to chop them into smaller pieces first.
- Starch: A chain of linked glucose units, and amylase is the enzyme built specifically to cut the bonds joining those glucose units together, releasing maltose as the first product right in the mouth.
- Proteins: Broken down by enzymes like pepsin and trypsin further along the digestive tract, working on peptide bonds that amylase cannot touch.
Because amylase is shaped to act only on the glycosidic bonds in carbohydrates like starch, it plays no role in digesting fats, vitamins, or proteins. The correct answer is Starch.