What are Polysaccharides? | Brief introduction to Polysaccharides

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What are Polysaccharides?

Introduction to Polysaccharides

Polysaccharides play an important role in the human body. They are mostly used to store energy in the human body. There are many other functions of polysaccharides. In this article I will completely discuss polysaccharides, what are polysaccharides, the importance of polysaccharides, what is Starch, what is Glycogen, the Role of Cellulose and what is Agar. This article will focus only on Polysaccharides instead of other types of carbohydrates. If you want to know about the importance of carbohydrates, then click on the given link and read our article about the Importance of Carbohydrates in the body:

Video about what are Polysaccharides?

What are polysaccharides?  Definition:

Polysaccharides are polymers of many monosaccharides. When a large number of disaccharides and monosaccharides combine with each other they form polysaccharides. Polysaccharides have a huge role in our body they play important functions in the form of starch, glycogen, cellulose, pectins, and agar. Some of them are digestible and some are not.


Polysaccharides have an important role in the human body. Some most common functions are given below:

Store energy:

Polysaccharides are used to store energy in the form of starch and glycogen.

To improve the digestive system:

Polysaccharides are used in the diet to improve the digestive system. Such cellulose.

Important types of polysaccharides are given below one by one:

What is Starch?

Starch is a white tasteless powder. These are non-crystalline polysaccharides. Starch is also called Homoglycans because if we discuss the structure of starch, they are polymers of glucose. According to some researches, starch is the polymer of 4000 to 15000 units of glucose. It is a big molecule. There is alpha-(1 to 4) linkage is present between glucose to glucose.

There are further two types of starch:

  1. Amylose
  2. Amylopectin


Amylose is straight-chain carbohydrates. It has alpha – (1 – 4) linkage between their molecules.


Amylopectin is branched-chain polysaccharides. It has alpha – (1-4) linkage and branch on alpha – (1-6) linkage.

Nutritional Value of Starch:

They are used as energy in the diet because they have a large amount of energy in the form of glucose. They are only present in plants because of plan store energy in the form of glucose or starch. On consumption, they hydrolyzed in the stomach and used as a source of energy. After digestion, they convert into glycogen and stored in the liver or converted into fats and stored in adipose tissues.

Sources of starch:

They are found in:
  • Wheat
  • Rice
  • Barley
  • Maize
  • Tubers etc.

One gram of starch gives about 16kJ calories. But their excessive use may cause obesity.

What is Glycogen?

Glycogen is also another example of polysaccharide. These are only found in animals. Glycogen has the same structure as starch. Glycogen is also used for energy purposes. Starch stores as glycogen in animals. Glycogen has bigger structure than starch. They are polymers of 3,000 to 60,000 glucose units. They are found in animal liver and muscles. According to some researches 7% glucose found in the liver and 1% glucose found in muscles. This stored glucose in the form of glycogen is used in an emergency condition.

Excessive storage may cause diabetes.

Role of Cellulose:

Cellulose is also polymers of glucose. They combine with the Beta – (1 – 4) linkage. They are insoluble in water. And the human digestive system cannot digest it. Cellulytic is an enzyme used to digest it. They are used to improve the digestive system. It is also important for the proper functioning of the intestine. Dietary fibers are also cellulose. If you want to know about dietary fibers, then click on this link and visit our article:

Cellulose should be consumed it an appreciable quantity. For example, CMC carboxymethyl cellulose is used as a thinking and bulking agent.


Commonly they are found in Fruits and Vegetables.

What is Agar?

Agar is another interesting type of polysaccharides this is also called agar and vegetable gelatin. This was discovered from seaweed, Gelidium algae and genera and agar is also used to improve the digestive system. And for the proper functioning of intestine like cellulose. This gives the adhesive and gummy appearance. It is used in jellies, ice creams, etc and it assists in the passage of digestible materials and wastes through the intestines.


In the end in light of the above discussion, we can say that polysaccharides are very important for the human body. Their different types give different functions. They are used as a source of energy. But their excessive use may cause some diseases.

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