Glucose can be obtained from starch by hydrolysis. Hydrolysis is a chemical reaction in which water is used to break down a compound into smaller molecules. In the case of starch, hydrolysis breaks down the long chains of glucose molecules into individual glucose molecules. This reaction is often catalyzed by enzymes such as amylase, which are found in saliva and the pancreas. The resulting glucose molecules can then be used by the body as a source of energy.