Glucose, << GLOO kohs, >> is a type of sugar. It is sometimes called grape sugar or blood sugar. Glucose is a product of photosynthesis in green plants and is the chief source of energy for most living organisms, including human beings. Honey and such fruits as grapes and figs contain large amounts of glucose. Pure glucose is a white crystal. It is about three-fourths as sweet as sucrose (table sugar).
Glucose belongs to a class of foods called carbohydrates. It is the most abundant of the monosaccharides, which are the simplest carbohydrates. Because of its simple chemical structure, glucose can be absorbed directly into the blood from the intestine. Most complex carbohydrates, such as glycogen and starch, must be broken down into monosaccharides before they can be absorbed into the blood.
The blood normally is about 0.1 per cent glucose. After a meal rich in carbohydrates, the amount of glucose in the blood rises and remains higher than normal for a brief period. The extra glucose is rapidly removed from the blood and stored in the liver and muscles as glycogen. When quick energy is needed, stored glycogen is converted back into glucose. If the glycogen storage areas are full, excess glucose may be converted into fat.
In the disease diabetes mellitus, glucose is not efficiently used by the body cells, and the amount of glucose in the blood remains abnormally high. As the blood moves through the kidneys, some excess glucose passes into the urine. Urine is analyzed for the presence of glucose as a test for diabetes mellitus.
Glucose is made commercially from starch by treating the starch with acid under steam pressure. If all the starch is converted into glucose, the product is sold under the name dextrose. If the conversion is not complete, and a mixture of glucose and other sugars results, the product is sold as corn syrup. Manufacturers use dextrose and corn syrup in a wide variety of foods and beverages, including baked goods, candy, canned fruits, and soft drinks.
