Difference Between Glucose and Fructose

Dhristi JEE 2022-24

Glucose and Fructose Difference

Glucose and Fructose are two Simple Sugars. Simple carbohydrates are classified in two ways:

Monosaccharide: A monosaccharide is the most basic form of carbohydrates. The most fundamental source of carbohydrates is a monosaccharide. Within cells, monosaccharides have various roles. Monosaccharides are, first and foremost, used to generate and store energy. Most of the species produce energy by breaking down the monosaccharide glucose and processing the energy released from the bonds. Ex. glucose and Fructose.

Disaccharide: A molecule formed by two monosaccharides, or simple sugars, is a disaccharide, also called a double sugar. Disaccharides are formed by dehydration reactions in which a total of one water molecule is separated from the two monosaccharides. Ex. Sucrose, maltose, and lactose.


Glucose is a monosaccharide, also known as grape sugar. It is an aldohexose. Glucose is the preferred source of energy for our muscles and brain. 

Preparation of Glucose

1. From Sucrose (cane sugar): By boiling sucrose in an alcoholic solution with dilute HCl and H2SO4, we can obtain glucose and fructose in exactly equal amounts. 

C12H22O11(Sucrose)+ H2O → C6H12O6 (Glucose)+ C6H12O6 (Fructose)

2. From Starch: Glucose can be obtained by the hydrolysis of starch in boiled and dilute H2SO4 at 393 K under pressure.

(C6H10O4)n (Starch or cellulose) + nH2O + H+ → nC6H12O6 (Glucose)

Uses of Glucose

  • It is provided to patients who are extremely ill and unable to feed because it offers calories from carbohydrates

  • It is used in the treatment of low blood sugar. 

  • It is used for the synthesis of matter as a precursor.


Fructose is naturally found in fruits and vegetables, primarily metabolized in our livers.  Via glycolysis, fructose is used to generate energy. However, fructose is also involved in lipogenesis, which is how fat is formed, unlike glucose. Fructose belongs to a group called ketose. Oligosaccharides are formed when fructose interacts with other monosaccharides. With the help of a glycosidic bond, Sucrose has a fructose molecule joined with a glucose molecule.

Uses of Fructose

  • Crystalline fructose is used in the food industry to improve flavour.

  • It is found in flavoured water, energy drinks, items that are low in calories, etc.

  • In the manufacture of smooth, moist cookies, nutrition bars, low-calorie products, etc., fruit sugar is used.

How can fructose be harmful to your health?

Fructose can be harmful to your health in the following ways: 

Fructose alters blood sugar levels more slowly than glucose and appears to have no effect on insulin levels. Unlike glucose, which is digested throughout the body, fructose is metabolised almost exclusively by the liver. Overeating can lead to a fatty liver and visceral fat around vital organs over time. The increased frequency of nonalcoholic fatty liver disease is linked to the fructose-rich Standard American Diet. Insulin resistance and type 2 diabetes can be triggered by this disorder.

Furthermore, whereas glucose boosts the hormone of fullness, there is some evidence that fructose has the opposite effect. As a result, some specialists believe that high-fructose diets contribute to eating disorders. Simply put, if you do not feel satisfied, you will eat more.

Is this to say that we should not eat fruit because it is high in fructose? The answer is (for the most part) no. There are more aspects to consider in nutrition than just one unit of measurement, such as fructose content. Fruits, unlike fructose-rich but nutritionally deficient junk foods and drinks, include a variety of other beneficial components. Because they're high in water and fibre, their fructose is released slowly. Candy and drink, on the other hand, instantly flood the liver with sugar.

Fruits are also nutrient-dense, including a wide range of vitamins, minerals, antioxidants, and polyphenols. Diets high in fruits and vegetables have been linked to a lower incidence of heart disease, diabetes, and strokes in studies. They have even been connected to better mental wellness.

Having said that, veggies, rather than fruits, should provide the majority of your carbohydrates. While most people can tolerate fructose from fruits, diabetics should be cautious. Consult your doctor to determine the amount of fructose that is safe for you to consume.

Solved Examples

1. How Can We Obtain Glucose from the Starch?

Ans: Glucose can be obtained by the hydrolysis of starch in boiled and dilute H2SO4 at 393 K under pressure.

(C6H10O5)n (Starch or cellulose) + nH2O + H+ → nC6H12O6 (Glucose)

2. What are Some of the Common Differences Between Glucose and Fructose?

Ans: Glucose is a 6 membered ring, whereas fructose is a 5 membered ring. Glucose produces less fat compared to fructose in our bodies. Glucose is aldohexose, whereas Fructose is Ketohexose. 

3. What is Fructose Used for?

Ans: The basic natural sugar present in bananas, honey, and vegetables is fructose. Fructose has been used as a sweetener for a long time in its pure form and has benefits for certain groups of people, including individuals with diabetes and those seeking to control their weight. 

4. What are Some of the Physical Properties of Glucose?

Ans: Glucose has the chemical formula C5H12O6 with a molecular weight of 180.16 g/mol. It’s a monosaccharide, with a density of 1.54 g/cm3.

5. What are the Properties of Fructose?

Ans: Compared to other carbohydrates, such as glucose, which has a melting point of 146 ° C, fructose has a lower melting point. The fructose compound has a molar mass of 180.16 mol / g and a density of 1.69 g / cm2. Refined fructose that is crystallized is pure and powdery. 

Fun Facts

  • Fructose has been used as an artificial sweetener for the past 20 years in foods and beverages. 

  • Natural fructose is a natural form of sugar. However, in junk foods, artificially produced fructose is used as a preservative, causing weight gain if so much is eaten over time.

  • Fructose is sweeter than sucrose, but less is required to obtain the same sweetness by providing calorie reductions.

  • Glucose is classified as a Hexose due to the presence of 6 carbons. 

  • Pure glucose is crystalline or in the form of white powder. 

This is all about glucose, fructose, and their differences. Focus on the conceptual points and understand the differences well. Check out how they are used in daily life and prepare the topic well. 

FAQs on Difference Between Glucose and Fructose

1. What are the primary differences between glucose and fructose?

The primary differences between glucose and fructose are:

Both fructose and glucose are monosaccharide sugars that are straightforward to make. When starch and sugar, whether sucrose or high-fructose corn syrup (HFCS), are digested, they produce a lot of glucose.

The tricarboxylic acid (TCA) cycle absorbs and transports glucose directly to body cells, where it fuels metabolism and finally forms water and carbon dioxide. It does not undergo hepatic absorption, and when there is an excess of energy, another pathway is utilised to store it as glycogen, and a third mechanism is used to convert it to fatty acids and deposit it in fat tissue as triglycerides.

When chronic energy overconsumption occurs, both muscle and fat cells become insulin resistant, and glucose absorption at the periphery decreases, resulting in increased insulin production as the cells require more glucose. Type 2 diabetes mellitus develops as a result of this process.

2. How is fructose used for commercial purposes?

Fructose, dextrose, and small amounts of oligosaccharides make up high-fructose syrups (HFS). The most common commercial syrups include between 42 and 55 percent fructose. Concurrent breakthroughs in refining, isomerization, and separation technologies in the 1960s enabled HFS manufacture. 

Sweetness, flavour enhancement, humectancy, colour and flavour development, freezing-point reduction, and osmotic stability are only a few of the physical and functional properties of fructose in food and beverage applications. Carbonated beverages, baked items, canned fruits, jams and jellies, and dairy products all use HFS. The usage of crystalline fructose and crystalline fructose syrup in popular food and beverage applications has lately extended from pharmaceutical and specialised food items.

3. How to consume sugar without harming your health?

The greatest approach is to eat full, natural foods. Sugar can be found in fruits, vegetables, and cereals. However, they are all high in fibre, which slows the absorption of sugar. Furthermore, consuming a wide range of fresh produce broadens the range of critical vitamins and minerals absorbed and processed by your body.

However, as previously said, sugar is sugar. Whether you receive it from cupcakes or carrots, you should talk to your doctor about your individual safe consumption limit. Inflammation and gastrointestinal issues are caused by consuming too much sugar. Sugar-sensitive people frequently adopt a low-FODMAP diet, which mostly eliminates fructose, to help prevent this.

The lesson here is to eat foods in their most natural state. For example, instead of refined grains, use brown rice or a piece of fruit that contains all of the plant's fibre. This will provide the body with the glucose it requires for energy while also supplying fibre, which is an important component of a balanced diet. 

4. How does Glucose raise sugar levels in your body?

You will note that each of these foods is quite filling. This is because glucose elevates blood sugar levels once it is absorbed by the small intestine. This increases insulin synthesis, which leads to the development and secretion of leptin. The "fullness hormone," or leptin, does exactly what it says on the tin: it makes you feel full.

When we speak of blood sugar, we are actually talking about blood glucose. The amount of glucose in your bloodstream is measured here. Glucose passes through your bloodstream, delivering energy to all of your body's tissues that require it. That is why, of the three macronutrients (carbohydrates, fats, and proteins), we refer to carbohydrates as our primary energy source. Common sources of glucose are oats, rice, pasta, bread, and starchy vegetables.

5. Which Foods are Having Fructose in it?

Sugars, including fructose, are naturally present in all fruits, which is why fructose is also found in 100% of fruit juices. If the fructose part of sucrose (glucose + fructose) is not taken into account, the amount of fructose in the fruit section varies, depending on the type, from 1 to 6 g for citrus fruits, about 7 g for pineapple, and 3 to 10 g for apples and pears.

The fructose content of fruit juices, as predicted, represents the entire fruit composition and ranges from 0.5 to 7 g per 100 g of typical juices. 100 ml of orange juice, for example, contains 2.4 g of fructose, while 100 g of whole orange juice contains 2.2 g of fructose. The fructose content for apples is 6.7 g in the whole fruit and 5.5 g in the juice.

6. What are Sugars?

Sugars are carbohydrates that are chemically classified as monosaccharides and disaccharides that act as the body’s primary supply of nutrition. There are a variety of sugar types. In many foods, they exist both naturally and as ingredients. The most familiar sugar is sucrose. It is made of two simple sugars, fructose, and glucose. Fruits and vegetables contain fructose and glucose naturally. Inverted sugar, corn syrup, high fructose corn syrup, butter, lactose (milk sugar), and other syrups are other sugars used in foods. All those sugars except lactose break down into fructose and glucose during digestion. Lactose disintegrates into glucose and galactose.