Difference Between Glucose and Sucrose

Main Difference – Glucose vs Sucrose

Both glucose and sucrose are simple sugars. They are very sweet tasting compounds and dissolve well in water. These compounds have different uses due to their sweetness. The main difference between glucose and sucrose is that glucose is a monosaccharide whereas sucrose is a disaccharide. A monosaccharide occurs as a single molecule. A disaccharide is composed of two monosaccharide molecules bonded to each other through a glycosidic bond. Sucrose is a disaccharide composed of one glucose molecule and one fructose molecule.

Key Areas Covered

1. What is Glucose
      – Definition, Structure, Properties, and Uses
2. What is Sucrose
      – Definition, Structure, Properties, and Uses
3. What is the Difference Between Glucose and Sucrose
      – Comparison of Key Differences

Key Terms: Disaccharide, Fructose, Glucose, Glycosidic Bond, Monosaccharide, Sucrose, Sugar, Sweetness

What is Glucose

Glucose is a simple sugar having the chemical formula C₆H₁₂O₆. It is a monosaccharide that is useful in the formation of important disaccharides and polysaccharides. The molar mass of glucose is about 180 g/mol. It appears as a white powder. Glucose dissolves well in water. The melting point of this compound ranges from 146^oC to 150^oC depending on the chemical structure of the molecule.

The structure of glucose can be given in different forms such as Fischer projection, Haworth projection, and chair conformation. Let us consider the Fischer projection which is easier to study. The following image gives the Fischer projection of the two forms of glucose. Glucose can be found in the forms of D-glucose or L-glucose. They are enantiomers and are mirror images of each other.

Figure 1: Fischer Projection of Glucose Molecule

The most abundant form is D-glucose whereas L-glucose is less abundant. D-glucose is also called dextrose which is found as an ingredient in commercially available food items. Glucose is an important compound used in the food industry; it also has medical uses such as in the production of drugs to treat patients with hypoglycemia.

Sources of glucose include most of the carbohydrates that we consume. Here, glucose may be included either in monosaccharide form or as a building block of polysaccharides. Glucose is a good energy source for athletes to gain energy.

What is Sucrose

Sucrose is a disaccharide sugar having the chemical formula C₁₂H₂₂O₁₁. It is made up of two monosaccharide molecules. They are glucose and fructose. The linkage between these two monosaccharides is called a glycosidic bond. The molar mass of sucrose is about 342.29 g/mol. Sucrose is a non-reducing sugar molecule found in the solid form. Sucrose is a white, odorless and crystalline solid compound.  

Figure 2: The Chemical Structure of Sucrose

The major source of sucrose is sugar cane. Sugarcane plant is processed to obtain sucrose in the form of table salt that we consume in our day to day life. Sucrose has a high degree of sweetness. Therefore, it is used as a sweetener for soft drinks and many other food items. However, the glycemic index of sucrose is comparatively low. That is due to the presence of 50% fructose in the structure of sucrose. Therefore, sucrose has a minimal effect on the blood sugar.

The melting point of sucrose is around 185^oC. Upon further heating, sucrose decomposes into invert sugar. Invert sugar includes glucose and fructose molecules. Therefore, decomposition of sucrose is the breakdown of sucrose molecules into glucose and fructose.

Difference Between Glucose and Sucrose

Definition

Glucose: Glucose is a simple sugar having the chemical formula C₆H₁₂O₆.

Sucrose: Sucrose is a disaccharide sugar having the chemical formula C₁₂H₂₂O₁₁.

Nature of Molecule

Glucose: Glucose is a monosaccharide.

Sucrose: Sucrose is a disaccharide.

Reduction

Glucose: Glucose is a reducing sugar.

Sucrose: Sucrose is a non-reducing sugar.

Glycosidic Bond

Glucose: Glucose has no glycosidic bonds.

Sucrose: Sucrose has glycosidic bonds between glucose and fructose molecules.

Molar Mass

Glucose: The molar mass of glucose is about 180 g/mol.

Sucrose: The molar mass of sucrose is about 342.29 g/mol.

Melting Point

Glucose: The melting point of glucose is about 146-150^oC.

Sucrose: The melting point of sucrose is about 185^oC.

Glycemic Index

Glucose: The glycemic index of glucose is relatively high in D-glucose.

Sucrose: The glycemic index is relatively low in sucrose.

Conclusion

Glucose and sucrose are very common forms of sugars. They are sweet tasting compounds. Therefore, these compounds are used as sweeteners in the food industry. However, these sugars are different from each other according to their chemical structure and other properties. The key difference between glucose and sucrose is that glucose is a monosaccharide whereas sucrose is a disaccharide.

References:

1. “What is Sucrose? – Function, Structure & Chemical Equation.” Study.com, Available here.
2. “D-Glucose.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
3. “Sucrose.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “DL-Glucose” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Sucrose structure formula” By Bas – Self-made with Sucrose-inkscape.svg from the Commons (CC BY-SA 3.0) via Commons Wikimedia (Color Changed)