Difference Between Starch and Cellulose

Introduction

Carbohydrates or macromolecules are made up of elements carbon, hydrogen and oxygen, cellulose, and starch are the basic examples of carbohydrates. Starch has been used for a variety of uses for several years ago. But the proper understanding of this chemical constituent and its molecular structure has been obtained after the discovery made by Leeuwenhoek by discovering it microscopically as a discrete granule. Several types of research made in the field lead to the proper understanding of its molecular structure and architectural arrangement. Cellulose is the most abundant organic polymer. The French chemist Anselme Payen 1838 discovered cellulose which is the basic unit of plant cells. He isolated it from plants and determined chemical formulas. Hermann Staudinger 1920 discovered the polymeric structure of cellulose.

Starch

White organic granule produced by plants with the chemical formula (C₆ H₁₀ O₅ )_n. It is a complex carbohydrate found naturally in plants. Most fruits and vegetables store their energy in the form of starch. This is an important source of Carbohydrates, and it is edible and has some other vitamins, and minerals too. It is a polymer and is also given the name amylose. It contains two glucose molecules one which is linear chain amylose and the other which is in the coiled form amylopectin. Amylopectin is in crystalline form while amylose is not. This unit varies with varying plants. It consists majorly of D-glucose. Starch is produced by plants by using dehydration synthesis. At first, the plants convert the glucose present in them to glucose-1-phosphate by the phosphorylation process. And plants store the starch produced in the form of granules. Starch is present in all plant seeds and tubers where they store starch to store the extra glucose they obtained, and it can further release energy when photosynthesis is not happening by oxidative phosphorylation. A plant and animal also store this glucose in the form of glycogen which is also called animal starch. Animal starch is also present, but it has no chemical similarities with starch because it is a glycogen unit present in animals which has some structural similarities with the molecule amylopectin.

Structure of Starch

There are two structures for starch and are amylose and amylopectin. About 20-30 percent of starch is made up of Amylose while 70-80 percent is made up of amylopectin. The linear chain of glucose units is amylose while the amylopectin contains branched glucose units so more glucose is present. But the bonding is weak compared to amylose. So, amylopectin dissolves in water while amylose does not dissolve in water. The structure of amylose and amylopectin is,

Cellulose

Cellulose is a polysaccharide or carbohydrate that contains more than 3000 units of glucose. Polysaccharides are synthesized naturally in plants and animals. The chemical formula of cellulose is (C₆ H₁₀ O₅ )_n. Cellulose is present naturally in plants. About 33 percent of all vegetables, 50 percent of wood, and 90 percent of cotton are composed of cellulose. So, it is the most abundant naturally occurring organic component. It is a food for herbivorous animals and termites which is an insect. But it is indigestible to human beings. In animals, the microorganisms present in the alimentary tract help in the digestion process, but it is absent in human beings. In humans, the breakdown of beta acetal linkages of cellulose is not possible. But it has some other applications in human life such as it helps in the production of paper, plastics, photographic films, and fibres. Other cellulose derivatives are also used in the manufacture of explosives, thickening agents for foods, adhesives, etc.

Structure of Cellulose

In the structure of cellulose, there is a long chain of glucose is present and these glucose units are connected by beta acetal linkage. It is a straight-chain polymer unit consisting of glucose that does not have any branching or coiling. So, the structure of cellulose consists of a rod-like appearance. Therefore, the tensile strength of the cellulose is very high. And is also due to the presence of multiple hydroxyl groups. The presence of this cellulose is responsible for the strength of wood and stems of plants. The subunits present in cellulose are glucose and the bond is present in beta 1-4 glycosidic bonds. The hydroxyl group in the anomeric carbon of these compounds is directed above the plane of the glucose ring and shows a beta orientation. It has an inverted structure in which 4th carbon will be directed upwards. The structure of cellulose is,

Structural Difference Between Starch and Cellulose

Starch is a coiled structure while cellulose is a straight chain polymer. Starch contains two types of structural units one is straight chain while the other is in a coiled form. The linear one is amylose and the coiled one is amylopectin. And cellulose contains 1-4 linkage of β glucose monomers. While in starch 1-4 linkage of α glucose monomers are found. And in starch, the glucose units are in the same direction while in cellulose it has an inverted structure. The structure of cellulose makes it thicker and possesses high tensile strength while the structure of starch makes it a soft chemical compound.

Difference Between Starch and Cellulose

The differences between starch and cellulose are tabulated below.

Cellulose	Starch
It is odourless and tasteless.	White and
Cellulose is insoluble in water and organic solvents.	Amylopectin is water-soluble while amylopectin is not soluble in water.
Straight chain polymer.	Coiled polymer.
It is more crystalline.	Less crystalline, also converted to amorphous by the supply of more heat.
The digestion process is difficult.	Easy digestion is present.
Humans are not consumed.	Humans can easily consume and are a good source of energy.
It contains only one type of beta glucose.	It contains two types of alpha glucose.
It gives structural rigidity to plants and trees.	It is used as a storage of energy.

Conclusion

Starch and cellulose are two different types of polysaccharides found in plants. The major difference between stars and cellulose is that cellulose is found in plants for giving proper structure and rigidity and is consumed by herbivorous animals. While starch is present in a plant cell to store the glucose for further energy production. There are generally two types of starch they are amylopectin and amylose. They are different in function and different in structure even though it contains the same glucose units. They are structurally different in the way that starch contains 1-4 linkage of α glucose and in cellulose 1-4 linkage of β glucose. Cellulose is more abundant than starch.

FAQs

1. Which food is high in starch?

Starch may be in amylopectin or amylose in food. Foods that are rich in starch are bananas, yams, potatoes, oats, pasta, pasta, bread, etc.

2. What does starch do to your body?

Starch is edible food that has an important function in humans. From starch, energy is obtained. The breaking of starch leads to the formation of glucose units. And glucose is an important source of energy. Depending on the type of starch they may be quickly digested, or it may take some time.

3. What are the types of starch?

Starch is classified into three types under its nutritional and digestive properties. They are Rapidly digestible starch, Resistant starch (RS), and slowly digestible starch. The starch that is commonly found in potatoes in the cooked form is rapidly digestible. The body that doesn't digest is resistant to starch. While the complex structure that slowly digests is slowly digestible starch.

4. What is saccharification?

The process of converting polysaccharides into corresponding saccharides is saccharification. And is present in starch.

5. Why is cellulose very stable?

Cellulose is very stable because of the strong hydrogen bonding present in the polysaccharide units. Thereby forming a network structure.