What are Polysaccharides_ Polysaccharides_Definition_structure

What are Polysaccharides?

Introduction:

Polysaccharides plays important role in human body. They are used to store energy in human body. There are many other functions of polysaccharides. In this article I will completely discuss about polysaccharides, what are polysaccharides, importance of polysaccharides, what is Starch, what is Glycogen, 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 importance of carbohydrates, then click on given link and read our article about Importance of Carbohydrates in body:

What are polysaccharides?

Definition:

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

Importance of Polysaccharides:

Polysaccharides have important role in 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 digestive system:

Polysaccharides are  in diet to improve 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 polysaccharide. Starch is also called Homoglycans, because if we discuss about structure of starch, they are polymers of glucose. According to some researches starch is 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:

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

Amylopectin:

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 diet, because they have large amount of energy in the form of glucose. They are only present in plants, because plan store energy in the form of glucose or starch. On consumption they hydrolyzed in stomach and used as a source of energy. After digestion they convert into glycogen and store in liver or convert into fats and store 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. They have same structure like starch. They are also used for energy purposes. Starch stores as a glycogen in animals. They have 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 liver and 1% glucose found in muscles. This stored glucose in the form of glycogen is used in 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 human digestive system cannot digest it. Cellulytic is an enzyme used to digest it. They are used to improve digestive system. It is also important for the proper functioning of 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 appreciable quantity. For example: CMC carboxymethyle cellulose is used as thinking and bulking agent.

Sources:

Commonly they are found in Fruits and Vegetables.

What is Agar?

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

Conclusion:

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