Final answer:
The amylase enzyme in saliva breaks down the starch in crackers into simpler sugars like maltose, making them taste sweet as they are chewed longer.
Step-by-step explanation:
If you chew a cracker long enough, it eventually tastes sweet because the amylase enzyme in your saliva is breaking down the complex carbohydrates (starches) into simpler sugars. This process of breaking down starch occurs because amylase specializes in cleaving the bonds within the long starch molecules. The starch in the cracker is essentially a long chain of glucose units, and while your sweet taste buds cannot detect the whole molecule, they are sensitive to individual glucose units or short chains of glucose. As you chew, the amylase enzyme in saliva breaks down these long starch molecules into smaller chains, e.g., maltose, which is composed of two glucose molecules. This enzyme is integral to the digestive process, beginning its work in the mouth and continuing in the small intestine with the help of pancreatic amylase.