Sucrose: The Chemical Name for Table Sugar
When most people refer to sugar, they are thinking of sucrose. This disaccharide is composed of one glucose molecule and one fructose molecule bonded together. Its chemical formula is C₁₂H₂₂O₁₁, and it is extracted commercially from sugarcane or sugar beets. It is the standard against which the sweetness of other sugars is measured and is used extensively in food products.
Common Monosaccharides: The Simple Sugars
Monosaccharides are the basic units of carbohydrates. In food, the most important are glucose, fructose, and galactose.
Glucose
Glucose (dextrose or blood sugar) is a simple sugar with the chemical formula C₆H₁₂O₆. It is the body’s primary energy source. Glucose is found naturally in fruits and plant juices and is a component of sucrose, lactose, and starches. Industrially, it is produced from starch hydrolysis. Glucose is a reducing sugar and involved in the Maillard reaction.
Fructose
Fructose (fruit sugar) is a monosaccharide, C₆H₁₂O₆, with a different structure than glucose. It is the sweetest natural sugar found in fruits, honey, and some vegetables. High-fructose corn syrup is also a common source.
Galactose
Galactose does not typically occur freely but is part of the disaccharide lactose. Its primary source in the diet is milk sugar. Lactase breaks down lactose into glucose and galactose during digestion.
Disaccharides: The Double Sugars
Disaccharides form when two monosaccharides link. Besides sucrose, lactose and maltose are common food disaccharides.
Lactose
Lactose (milk sugar) is a disaccharide of glucose and galactose found in mammalian milk and dairy. Lactose intolerance results from insufficient lactase.
Maltose
Maltose (malt sugar) is two linked glucose molecules. It is produced during grain fermentation and found in products like beer. Maltase breaks it into two glucose molecules.
Comparison of Common Food Sugars
| Feature | Sucrose (Table Sugar) | Glucose (Dextrose) | Fructose (Fruit Sugar) | Lactose (Milk Sugar) |
|---|---|---|---|---|
| Chemical Type | Disaccharide | Monosaccharide | Monosaccharide | Disaccharide |
| Composition | Glucose + Fructose | Single Unit | Single Unit | Glucose + Galactose |
| Formula | C₁₂H₂₂O₁₁ | C₆H₁₂O₆ | C₆H₁₂O₆ | C₁₂H₂₂O₁₁ |
| Key Source | Sugarcane, Sugar Beets | Corn, Starch | Fruits, Honey | Dairy Products |
| Sweetness (vs. Sucrose) | 1.0 (Reference) | ~0.6 | ~1.2 - 1.5 | ~0.35 |
| Classification | Non-reducing sugar | Reducing sugar | Reducing sugar | Reducing sugar |
The Role of Sugars in Food and Health
Sugars provide sweetness and contribute to browning, flavor, and texture in food. They also help preserve food by controlling moisture. Different sugars have different properties; for example, fructose retains moisture well, and both glucose and fructose are key to caramelization.
Naturally occurring sugars in whole foods come with fiber, vitamins, and minerals. Added sugars are concentrated, offering energy without significant nutrients. Excessive added sugar intake is linked to health issues like obesity and type 2 diabetes. The WHO suggests limiting free sugars to less than 10% of total energy intake.
Conclusion
There isn't a single chemical name for all sugar in food. Table sugar is sucrose, but food contains various sugars like glucose, fructose, and lactose. Recognizing these forms helps in understanding nutrition and food science. The source of sugar—whole foods versus processed—is more critical for health than the specific chemical name. For further reading on sugar's role in food, visit the Institute of Food Science and Technology.
