Caloric Sweeteners

Sweeteners can be classified into two general groups: caloric (or nutritive) and noncaloric (or non-nutritive) products. Caloric sweeteners are natural products, such as sucrose, fructose, glu-

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Year

Per capita consumption of caloric sweeteners

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Chemical structures of three sugars: sucrose, glucose, and fructose

cose, sorbitol, and mannitol, that provide between 2.6 and 4 calories per gram. Noncaloric sweeteners are synthetic products, such as saccharine and aspartame, that provide very few or no calories. Noncaloric sweeteners are also called artificial sweeteners or sugar substitutes. The graph on page 58 shows trends in the consumption of sugar and other sweeteners in the United States from 1980 to 2003. The graph shows trends in consumption of three kinds of sweeteners: refined sugar from sugarcane and sugar beets; corn sweeteners, which include glucose and dextrose; and high-fructose corn syrup.

Unless otherwise indicated, the term sugar usually refers to the disaccharide sucrose, whose chemical structure is shown above. Disaccharides consist of two molecules of one or more simple sugars bonded to each other. The two components of sucrose are two molecules of glucose (also known as dextrose, grape sugar, or corn sugar). When a molecule of sucrose is metabolized, it produces two

molecules of glucose, the molecule primarily responsible for the release of energy in the human body:

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sucrose glucose

Glucose is a monosaccharide, the simplest type of sugar. Although glucose is the name chemists prefer, it is frequently referred to as dextrose. The structural formula of glucose is shown on page 59, with that of sucrose. It is obtained commercially from the hydrolysis of corn starch or other cellulose-containing materials, with either acids or enzymes used as catalysts in the reaction.

High-fructose corn syrup (HFCS) is a liquid mixture of glucose and fructose made by treating glucose-rich corn syrup with enzymes. Fructose occurs naturally in many kinds of fruit and is also known as fruit sugar or levulose. It is very desirable as a sweetener because it is about 75 percent sweeter than sucrose. High-fructose corn syrup may contain anywhere from about 42 to 99 percent fructose. Fructose is a monosaccharide with a chemical structure very similar to that of glucose. The structural formula for fructose is shown on page 59 with that of sucrose and glucose. Many nutrition experts classify HFCS as a synthetic food because it is produced by industrial means and is not a natural product itself.

HFCSs first became commercially available in 1967, but they did not become widely popular until the late 1970s. This increase in popularity came about when makers of the sweetener significantly increased the concentration of fructose in HFCS mixtures. As a result, HFCSs became highly desirable as substitutes for both sucrose and glucose in soft drinks, jams and jellies, confectionery products, frozen desserts, condiments, bakery products, and canned fruits and juices. The substitution of HFCSs for sucrose and glucose in food products has raised concerns among nutritionists, however, because they may contribute to the increasing amount of sweet foods in the average American's diet.

In fact, health concerns about the growing proportion of sweet foods in the American diet have led to greater interest in the use of artificial sweeteners as substitutes for glucose, fructose, and sucrose in processed foods. The other important reason for such interest is the problem of diabetes, the inability of some persons to metabolize glucose. An excess or deficiency of glucose in a diabetic's diet is not just a long-term concern; it can lead to serious short-term health problems, including coma and death.