Sucrose

OVERVIEW

Sucrose (SUE-krose) is a white crystalline solid or powder with no odor but a characteristic sweet taste. It is the most widely used sweetener in the world. When heated, it tends to decompose, breaking down into carbon and water. The presence of carbon accounts for the increasing dark color of the compound as it caramelizes (changes from sucrose to caramel).

Sucrose is a disaccharide, a carbohydrate that consists of two monosaccharides. The carbohydrates are a large family of organic compounds that contain carbon, hydrogen, and oxygen, the latter two in a ratio of about two to one (as is the case with water). Thus the name "carbo-hydrate." Some familiar monosaccharides are glucose, fructose, and galactose; while the disaccharides include sucrose, maltose (malt sugar), and lactose (milk sugar). Sucrose molecules consist of a molecule of glucose joined to a molecule of fructose.

KEY FACTS

OTHER NAMES:

Saccharose; table sugar; beet sugar; cane sugar

FORMULA:

C₁₂H₂₂O₁₁

ELEMENTS:

Carbon, hydrogen, oxygen

COMPOUND TYPE:

Carbohydrate; disaccharide (organic)

STATE:

Solid

MOLECULAR WEIGHT:

342.30 g/mol

MELTING POINT:

185.5°C (365.9°F); begins to decompose at about 160°C (320°F)

BOILING POINT:

Not applicable

SOLUBILITY:

Soluble in water; slightly soluble in ethyl alcohol

The use of sugar is thought to have originated in Polynesia, from where it later spread to India. Probably the first recorded reference to sugar dates to 510 bce when the Persian emperor Darius referred to sugar cane growing on the banks of the Indus River as "the reed which gives honey without bees." Knowledge of sugar later spread across Asia into North Africa, but reached Europe only in the eleventh century. Warriors returning from the Crusades brought back stories about a new spice with a very pleasant flavor. Since growing sugar cane in Europe was difficult, the "new spice" was difficult to obtain and very expensive.

The sugar cane plant was brought to the New World on the earliest voyages of Christopher Columbus. His crew found that the plant grew easily in the congenial climate of the West Indies, and it rapidly became one of the most important crops cultivated by Europeans. Indeed, some authors have observed that the profits from sugar exportation to Europe far exceeded the vast treasurers of gold for which early explorers searched, and never found.

HOW IT IS MADE

Sucrose occurs naturally in a number of plants, primarily sugar cane and sugar beets. Sugar cane is the source of about 70 percent of the world's sucrose, and sugar beets account for the remaining 30 percent. Small amounts of sucrose are also obtained from sugar maple trees and sorghum, a cereal grain crop.

The process of making sugar depends on the source from which it is extracted. With sugar cane, the plant stalks are crushed to obtain the sweet juice they contain. The juice is treated with lime to remove impurities and then boiled until the juice thickens into a syrup. Evaporation of the syrup produces crystals of sucrose. Juice remaining after the evaporation step is sold as molasses. Stalks remaining after the juice has been extracted can be used as a fuel in the plant's boilers.

Sugar beets are harvested in the fields, washed, and cut into small pieces. The beet chips are then soaked in water and pressed to extract the sweet juice in them. The juice is boiled and the liquid evaporated to obtain crystalline sucrose. The solid material remaining from this process can be used as animal feed.

COMMON USES AND POTENTIAL HAZARDS

Sucrose is used almost entirely for human consumption in one form or another. The compound has two important functions. First, its sweet flavor makes foods more palatable and pleasant to eat. Second, its digestion results in the release of energy used by the body for growth, development, and everyday activities. When sucrose is digested, it first breaks down into the monosaccharides of which it is composed, glucose and fructose, with the release of energy stored in chemical bonds. Next, each of these monosaccharides is itself digested, resulting in the formation of carbon dioxide, water, and additional energy for body functions.

Sucrose is available in many forms, ranging from cubes to crystalline granules to finely ground sugar to powdered sugar. All forms of sucrose have identical chemical and biological properties. Impure forms of sugar are also available. Brown sugar, for example, contains small amounts of molasses that are not removed during the sugar refining process.

Sucrose is used as a food additive in an almost unlimited variety of food products, including jams and jellies, candies, cakes and pies, ice cream and sherbet, and all types of canned and frozen foods. It serves a number of purposes in processed foods, including:

• To add sweetness to foods;
• As a preservative in jams and jellies;
• To increase the boiling point or reduce the freezing point of foods;
• To make possible the fermentation of foods by yeast;
• To improve the color or flavor of certain food products;
• As a demulcent, a substance that soothes the mucous membranes; and
• To add crispness to food products that do not have sufficient natural moisture.

Interesting Facts

• Early European physicians recommended sugar for the treatment of diseases. Both Buddha and Mohammad suggested its use as a medicine.
• The alcoholic drink rum was first produced in the West Indies in the early sixteenth century by the distillation of sugar juice. Rum was first considered a drink suitable only for common people, but eventually spread to Europe and became popular among the upper classes as well.

Sucrose also has a limited number of industrial applications unrelated to the food industry. It is used in the production of some plastics, such as rigid polyurethane foams, in the manufacture of inks, and in the production of some types of soap.

Consumed in moderate amounts, sucrose poses no health hazards to humans or other animals. Eating excessive amounts of sucrose, however, is related to a number of health problems, most important, dental caries (tooth decay) and obesity. Sucrose is an important factor in the development of tooth decay because it provides the primary nutrient needed by bacteria living in the mouth. Cleaning one's teeth regularly is the best single way of preventing dental caries caused by the consumption of sucrose. Obesity is a problem that develops when a person consumes more foods than needed for normal healthy body function. When those foods are not utilized by the body, they are stored as fatty deposits, resulting in obesity and a number of health problems related to it, such as diabetes and heart disease.

FOR FURTHER INFORMATION

Mardis, Anne L. "Current Knowledge of the Health Effects of Sugar Intake." Family Economics and Nutrition Review (Winter 2001): 88-91. Also available online at http://www.cnpp.usda.gov/FENR/FENRv13n1/fenrv13n1p87.pdf.

"Sucrose." J. T. Baker. http://www.jtbaker.com/msds/englishhtml/s7394.htm (accessed on November 15, 2005).

"Sugar. Sweet by Nature." The Sugar Association. http://www.sugar.org/ (accessed on November 15, 2005).

"Welcome to the World of Sugar Technology." Sugar Knowledge International. http://www.sucrose.com/ (accessed on November 15, 2005).

"What Is Sugar?" The Accidental Scientist. http://www.exploratorium.edu/cooking/candy/sugar.html (accessed on November 15, 2005).

See AlsoFructose; Glucose; Lactose; Sucrose Polyester

sucrose (C₁₂H₂₂O₁₁) Common, white, crystalline sugar, a disaccharide sugar consisting of linked glucose and fructose molecules. It occurs in many plants, but its principal commercial sources are sugar cane and sugar beet. It is widely used for food sweetening and making preserves.

sucrose (sewk-rohz) n. a carbohydrate consisting of glucose and fructose. It is the principal constituent of cane sugar and sugar beet. The increasing consumption of sucrose in the last 50 years has coincided with an increase in the incidence of dental caries, diabetes, coronary heart disease, and obesity.

sucrose Cane or beet sugar. A disaccharide composed of glucose and fructose.

sucrose A disaccharide, composed of fructose and glucose, which is a common storage and transport sugar in plants. It is known commercially as cane or beet sugar.