What is the basic structural difference between starch and cellulose?
Solution and Explanation
Starch consists of two components - amylose and amylopectin. Amylose is a long linear chain of ∝-D-(+)-glucose units joined by C1-C4 glycosidic linkage (∝-link).
Amylopectin is a branched-chain polymer of ∝-D-glucose units, in which the chain is formed by C1-C4 glycosidic linkage and the branching occurs by C1-C6 glycosidic linkage.
On the other hand, cellulose is a straight-chain polysaccharide of β-D-glucose units joined by C1-C4 glycosidic linkage (β-link).
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Concepts Used:
Polysaccharides
Polysaccharides are the most abundant hydrocarbons that exist in our food. They are long chains of hydrocarbons inclusive of smaller units called monosaccharides or monomers, related to each other through glycosidic linkages. Cellulose, starch, chitin, and glycogen are the most common polysaccharides found in food.
Characteristics of Polysaccharides:
- Desiccation does not cause Polysaccharides to structure crystals.
- They do not have a candied flavor.
- Water cannot infiltrate the molecules due to the numerous hydrogen bonds, making them hydrophobic.
- They are osmotically inactive and close-packed inside the cells. Many are water-insoluble.
- They are collections of hydrogen, carbon, and oxygen. 2:1 is the ratio of hydrogen to oxygen.
- They are carbohydrates with a molecular weight comparatively more excessive than other compounds. It is also possible to extract a white powder out of it.
Types of Polysaccharides:
- Homopolysaccharides
- Heteropolysaccharides