Difference Between Sucrose and Fructose

December 2022 · 5 minute read

Glucose forms the basis of life. Our body consumes sugar to generate energy that we need to function. Due to complex chemistry, it comes in many forms. Sucrose and fructose are two forms of sugar that are present naturally and can be found in fruits. Glucose is found in complex and simple forms. Sucrose is a complex form of glucose as it has more than one monosaccharide unit in it. Fructose on the other hand is simple glucose as it is a monosaccharide. 

Sucrose vs Fructose  

The main difference between sucrose and fructose is that sucrose is a polysaccharide with two different units of monosaccharide in it, on the other hand, fructose is a monosaccharide. Two monosaccharides that form the part of sucrose are one unit of glucose and one unit of fructose.  Fructose is the basic unit that forms sucrose and other sugars. These two sugars are present naturally and can be found in plants and fruits.

A synthesized form of fructose and glucose is called sucrose. It is a natural sugar and falls under the category of polysaccharides. Sucrose is the sugar that we use every day in our food. This sugar form is bad for our oral health as it is the main ingredient that bacteria use to form a sticky substance and helps form plaque. As it is a type of natural sugar it is extracted from plants for our needs. Usually, we extract it from plant sources like beetroot and sugarcane.

Fructose is a simple natural sugar that has only one component in it. Fructose can be found in plants and fall under the ketonic sugar group due to the presence of a ketone group in its base structure. This monosaccharide is directly consumed by the body after consumption. Its excessive consumption causes obesity and also makes the body resistant to insulin among other ailments. It also leads to a cluster of diseases collectively called metabolic syndrome.  

Comparison Table Between Sucrose and Fructose

Parameters of ComparisonSucroseFructose
Saccharide typeIt is a disaccharide.It is a monosaccharide.
SweetnessIt is less sweet than fructose.It is sweeter than sucrose.
ComponentsIt has two components, fructose, and glucose. It has one component, Fructose.
Consumption after digestionIt is not consumed directly.It is consumed directly by the body.
Plaque formationIt causes plaque formation. It doesn’t cause plaque formation.

What is Sucrose?

Sucrose is a type of disaccharide that exists only in 𝛼 from, unlike one of the monosaccharide components in it called glucose which exists in both forms. Sucrose is formed with two components, glucose, and fructose which are attached with each other by a glycosidic bond. Sucrose is not a reducing sugar as the glycosidic bond utilizes the hydroxyl groups.

The bond formation between the two components is unique as both the reducing ends of the monosaccharides are utilized. Sucrose forms caramel when exposed to high temperatures which is a departure from the melting property of many compounds. It is a form of carbohydrate so the end result of its combustion is water and carbon dioxide.

Sucrose decomposes at a temperature of 367° F. Specific parts of plants such as fruits, roots, flowers contain sucrose. It is a natural sugar but can be synthesized through chemical processes as well. Ripe fruits contain a higher amount of sucrose and during the process of ripening the sucrose content rises rapidly.

Sucrose, however, may not be present in all types of fruits and flowers. Fruits such as lime, lemon, tomatoes, etc. do not contain any sucrose. The table sugar that we use in our homes for cooking comes mainly from two plant sources namely sugar beets and sugarcane. Other sugar crops are also available such as date palm, etc. 

What is Fructose?

Fructose is also known by the name levulose and the word fructose is formed of two parts. Fructus and a suffix -ose combine together to make the word. It means fruit sugar as the word fructus means fruit in Latin. Fructose when fermented anaerobically (in absence of air) forms drinking alcohol and carbon dioxide.

It is chemically present as a polyhydroxy ketone which takes a cyclical shape in crystalline form. In solution, it exists in an equilibrium of its cyclic forms and the open-chain form. When it is dehydrated it gives hydroxymethylfurfural which after further processing can give dimethylfuran in liquid form.

Dimethylfuran is an alternative to the carbon fuel such as petrol we use today. As of now, this is not used at a commercial scale as the refining process is costly. This is a commercially viable form of sugar for the beverage industry. It is relatively sweeter when compared to other carbohydrates like sucrose and can be twice as sweet as sucrose.

Its sweetness, however, depends on temperature, if the temperature increases its relative sweetness decreases. The decrease in sweetness with temperature is because the six-membered ring converts to a five-membered ring which is less sweet than the five-membered forms. The taste of sweetness is short-lived when compared with sucrose but at the peak, it gives a strong sweet taste.

Main Differences Between Sucrose and Fructose

  •  Sucrose falls under the category of disaccharides as it is formed of two monosaccharides whereas, fructose is a monosaccharide.
  • The sweetness of sucrose lasts for a long period when compared to the sweetness of fructose which lasts for a small moment.
  • Sucrose is a non-reducing sugar as it has no reducing anomeric hydroxyl group whereas, fructose is a reducing sugar as it has a free hydroxyl group.
  • Sucrose is less sweet in comparison to fructose and fructose can be twice as sweet as sucrose.
  • Fructose is the form of carbohydrate that is consumed directly by the body whereas, sucrose is not consumed directly by the body.
  • Conclusion

    Sugars are an essential part of our lives as we consume them every day in one form or the other. After technological advances, we have been able to extract a huge amount of sugars from different parts of plants. Plants are the only natural source of sugar and are found in many forms.

    All forms of natural sugar differ from each other on the basis of chemical and physical properties. Fructose and sucrose are two different forms of sugars that differ in many ways from each other. Fructose is a monosaccharide whereas, sucrose is a polysaccharide. This is one of the distinctions between them based on their chemistry. 

    References

  • https://academic.oup.com/ajcn/article-abstract/58/5/724S/4732301
  • https://www.degruyter.com/document/doi/10.1351/pac197850111409/html
  • https://www.sciencedirect.com/science/article/pii/S0065231808602838
  • https://books.google.com/books?hl=en&lr=&id=TYTnheXYWpUC&oi=fnd&pg=PA1&dq=sucrose+&ots=q0AtZvdF81&sig=c1wd9NQPJ9oYo-fxG-d8sdceP5A
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