Question
Describe about the structure, nature and properties of starch.
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Answer
- Starch is used for energy storage in plants. Potatoes, corn, wheat and rice are the rich sources of starch.
- It is a polymer of glucose in which glucose molecules are lined by α (1,4) glycosidic bonds.
- Starch can be separated into two fractions namely, water soluble amylose and water insoluble amylo pectin. Starch contain about 20% of amylase and about 80% amylopectin.
- Amylose is composed of unbranched chains upto 4000 α – D glucose molecules joined by α (1,4) glycosidic bonds.
- At branch points, new chains of 24 to 30 glucose molecules are linked by α (1,6) glycosidic bonds with iodine solution amylose gives blue colour while amylo pectin gives a purple colour.
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