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Polysaccharides also called as poly-carbohydrates are the most abundant carbohydrate found in food. they are long chain of polymeric carbohydrate which is composed of monosaccharide unit linked Together by glycosidic bond. Polysaccharides can react with water using an enzyme known as amylase, which acts as a catalyst. Their structure range is from linear to highly branched. Storage polysaccharide includes starch, glycogen and gallactogen. Whereas, structural polysaccharides include hemi cellulose and chitin.
What is the Structure of Polysaccharides?
Polysaccharides are made of repeating monosaccharide units joined together by glycosidic links. The bond consists of a molecule of oxygen that bridges two carbon rings. A bond is formed when a carbon of one molecule is a Hydroxide group and the hydroxyl group of another monosaccharide loses hydrogen.
This reaction is known as the hydration reaction because one molecule of oxygen in 2 molecules of hydrogen are removed. Therefore the structure of molecules combined define the structure of the polysaccharides.
Polysaccharides can differ in the structure depending on the position of monosaccharides as linear and branched. As the name defines the linear polysaccharide has sugars arranged from end to end In a linear fashion. Whereas, the branch of polysaccharides have sugars arranged in the branch form, off from the main chain.
The structure of polysaccharides influences the chemical and physical properties like – solubility, digestibility, and interaction with other molecules.
Types of Polysaccharides
Polysaccharides are divided based on their function, that is storage and structural polysaccharides. Let us discuss them briefly.
Also Check: Importance of Polysaccharides
Storage polysaccharides
Storage polysaccharides have the function of storing food and utilizing them when required. These polysaccharides are broken down into simpler sugars and metabolized when used.
Starch
- They are the primary energy storage in plants.
- It comprises two types of polysaccharides namely – amylose(linear) and amylopectin(branched).
- Found in seeds, tubers, and roots, in plants.
- It serves as an essential dietary source of carbohydrates for humans and animals.
Glycogen
- Main energy storage polysaccharide in animals and fungi.
- They are highly branched polysaccharides.
- In animals, glycogen is mostly stored in the liver and muscles.
- Plays an important role in blood sugar regulation.
Structural Polysaccharide
These polysaccharides provide support and protection to cells and tissues in plants, animals, and some microorganisms.
Cellulose
- Forms the primary structural component of the cell wall.
- Glucose molecules are linked together by β-1,4-glycosidic bonds, forming strong, rigid fibers.
- They are insoluble in water.
- Resistant to digestion to humans, and aids in digestion.
Chitin
- They provide strength and protection to organisms.
- Found in the exoskeleton of arthropods (e.g., insects, crustaceans) and the cell walls of fungi.
- Composed of N-acetylglucosamine units linked by β-1,4-glycosidic bonds.
Functions of Polysaccharides
Polysaccharides serve different functions to the organisms. Here are the functions mentioned below.
- Starch in plants and glycogen in animals are storage polysaccharides that can be used when required.
- Cellulose in plants and chitinin a arthropods and fungi help in providing structure support.
- Certain polysaccharides operate as protective barriers. Bacteria, for example, use capsular polysaccharides to protect themselves from host immunological reactions.
- Polysaccharides found on the cell surface like glycoproteins and glycolipid helps in cell to cell recognition and signalling and communication.
- They also help in immune responses, fertilization, and tissue development.
- Polysaccharide such as h hyaluronic acid helps in retaining the moisture in the tissues.
- Also, it helps in providing lubrication to the joints and hydration in the skin.
Do Check: Heteropolysaccharides
Application of Polysaccharides in the Food Industry
Polysaccharides are widely used in a variety of industries due to their different advantages. Its application in food industries is widely known and is being acknowledged worldwide.
Their property of providing stability, increased shelf life and quality enhancing properties makes it an ideal component in the food industry. Let us discuss the applications of polysaccharides below.
- Starch, pectin, and agar are used as thickening agents in the food industry. They are used in the production of sauces, desserts, jams, and dairy products.
- Alginate, derived from brown seaweed, has applications in wound dressings.
- Chitosan, a derivative of chitin, is used for its antimicrobial qualities and capacity to improve drug absorption.
- Hyaluronic acid is used as a moisture retention polysaccharide in the cosmetic industry.
- Polysaccharide such as chitosan is used in agriculture as a natural pesticide and fertilizer.
- Also, alginates are used to improve soil quality and water retention in soil.
Chitosan is used in water treatment to eliminate heavy metals and other pollutants.
FAQs on Polysaccharides
What are polysaccharides?
Polysaccharides, also known as poly-carbohydrates, are the most numerous carbohydrates present in diet. They are lengthy chains of polymeric carbohydrates made up of monosaccharide units joined together by glycosidic bonds
What are the two main types of polysaccharides?
Polysaccharides are divided based on their function, that is storage and structural polysaccharides. Storage polysaccharides include starch and glycogen, whereas, structural polysaccharides include cellulose and chitin.
What is cellulose, and where is it found?
Cellulose acts as a structural polysaccharide that helps provide support to the plants. It is found in the cell walls of plants.
What are some common examples of structural polysaccharides?
Common structural polysaccharides include cellulose in plants, chitin in arthropod and fungal exoskeletons, and peptidoglycan in bacterial cell walls.
What role do polysaccharides play in the food industry?
Polysaccharides help enhance the quality of food products by providing them longer shelf life, and stability and also act as thickeners.
