Glucose is a white crystalline sugar found in many fruits, animal tissues and fluids. It has half the sweetness of ordinary sugar, or sucrose, and is also referred to as a starch syrup, according to Dictionary.com.
German chemist Andreas Marggraf first isolated glucose from raisins in 1747. Glucose is a major energy source for many types of organisms, including humans and bacteria, and can be used in aerobic respiration, anaerobic respiration or fermentation. In plants, glucose can be stored as the polymers starch and as cellulose. In addition to being found naturally in food, glucose is heavily used in the manufacturing candy, jam, jelly and chewing gum.