Difference Between Starch and Cellulose

Introduction: Starch and Cellulose

Polysaccharides are the most abundantly available in nature among carbohydrates and perform a variety of functions, such as energy storage or as components of plant cell walls.

Polysaccharides are very large polymers made up of tens to thousands of monosaccharides, linked by glycosidic linkages. 

Ccommon polysaccharides: Starch, glycogen, and cellulose.

Heteropolymers can include, in addition to monosaccharides, sugars, amino sugars, or non carbohydrate substances. 

Heteropolymers are common in nature and are non reducing carbohydrates (with no sweet taste).


Starch:

Starch is a glucose polymer in which all repeat units are directed in one direction and connected by alpha bonds. Starch is edible and can be eaten safely by humans as we have the enzymes which can break it down into glucose.

It is a grain, with the main source for starch being potatoes, wheat, corn, and rice. These carbohydrates are broken down into glucose and used as a source of energy and a metabolism aid when reaching our bodies.

Starch is less crystalline and is weaker than cellulose. Despite the fact that raw starch is not soluble in cold water, it can be dissolved in warm water and can be used in different ways.

It's most commonly used as food but has other uses as well. It can be used as a glue, for tightening up clothes and weaving linen, for thickening sauces and for paper treatment.


Cellulose:

Cellulose is a glucose polymer whose units can be rotated around the axis of a backbone of glucose unit polymer chains, and are connected by beta links. It is the most natural organic compound and is a fundamental component of plant cells.

While humans can easily consume any type of cellulose, such as the outer shells of corn, the only animals that can digest cellulose are termites and cud-chewing goats, deer, or buffalo because they have some enzymes that can break down cellulose into glucose.

It has many commercial uses and is the main component of the paper and the fiber used to make clothes such as linen and cotton. Cellophane and rayon are also made from cellulose through dissolving the pulp by viscose, causing it to degrade and then dissolve it into cellulose xanthate in caustic soda.


Structural Difference Between Starch and Cellulose

Starch consists of two ingredients-amylose and amylopectin. Amylose is a long linear chain of ­-D-(+)-glucose units joined by glycosidic association C1-C4 (along-link).

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Amylopectin is a branched-chain polymer consisting of ‐D-glucose units in which the chain is formed by glycosidic connection C1-C4 and glycosidic connection C1-C6 branches..

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Cellulose, on the other hand, is a straight - chain polysaccharide with β - D-glucose units joined by glycosidic linkage C1-C4 (β-link).

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There are some parameters to differentiate between starch and cellulose.


Starch vs Cellulose

Parameter

Starch

Cellulose

Background

This word was derived from German language and it means strength, or to stiffen something.

It was discovered in 1838 from the plant matter and was used to produce thermoplastic for the first time

Glucose Range

Uses about 200-1000 glucose molecules to form one starch molecule

Takes up 500 glucose molecules to form one starch molecule.

Bonding

Hydrogen bonding

None

Role

To store energy in the form of carbohydrates

To form a specific structure of plants

Type of chain

They are coiled and unbranched (amylose) or long, branched (amylopectin)

These are long, straight, unbranched chains forming H-bonds with the adjacent chains

Solubility in water

Amylose is soluble in water, and amylopectin is insoluble in water.

Insoluble.

Forms

Grain form.

Fibres form.

Found in

It  is found in plants

it is found only in plants (cell wall).

Glucose unit linkages

Starch contains glucose residues as α(1-4) glycosidic bonds in amylose, while glycosidic bonds at branching points in amylopectin α(1-6), otherwise α(1-4) bonds.

Cellulose constitutes their residues of glucose as glycosidic bonds with β(1-4).

Molar mass

The molar starch mass varies.

162.1406 g/mol.

FAQ (Frequently Asked Questions)

1. How are Starch and Cellulose Similar and Different?

Starch and cellulose are two similar polymers commonly occurred. In fact, both are made of the same monomer, glucose, and have the same replicate units based on glucose. Only one difference does exist. All glucose-repeat units in starch are oriented in the same direction.

2. Why can Humans Digest Starch but not Cellulose?

Starch has a bond whereas a rubber has a cellulose. Bond cannot be digested by our intestines. The bond is for supporting structure. We do not want to be able to break down our structural support and that is why we need it in our food.

3. Explain the Structural Difference Between Starch and Cellulose?

Cellulose is mostly linear chains of glucose molecules bound by beta 1,4 glycosidic bonds while starch is present in both linear and branched chains.

Why is Cellulose Stronger than Starch?

They are bound together in cellulose, so that opposite molecules are rotated 180 degrees from one another. This seemingly minor change makes cellulose much stronger than starch, since parallel cellulose fibers stack up just like corrugated sheets stacked on top of each other.

What are Similarities Between Starch and Cellulose?

Starch and cellulose are two Polymers that are very similar. In addition, they are both made from the same monomer, glucose, and have the same glucose-based repeat units. Only one distinction does occur. In starch, all the repeat units of glucose are directed in the same direction.