Question
Explain the structure of starch.
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Answer
Starch is found in cereal grains, roots, tubers, potatoes, etc. It is a polymer of $\alpha$-D-glucose and consists of two components, amylose and amylopectin.
Amylose is water soluble component forms blue coloured complex with iodine. It constitutes about $20 \%$ of starch. Amylose contains 200 to $1000 \alpha$-D-glucose units linked together by glycosidic linkage between C-I of one unit and C-4 of another unit. i.e. $\alpha-1,4$ glycosidic linkages.
Amylopectin is insoluble in water and constitutes about $80 \%$ starch which forms blue-violet coloured complex with iodine. It is a branched chain polymer. In amylopectin, $\alpha$-D-glucose molecules are linked together by glycosidic linkage between $C _1$ - of one unit and $C -4$ of another unit to form long chain and branching acurs by glycosidic linkage between C-I and C6 glycosidic linkage.
Amylose is water soluble component forms blue coloured complex with iodine. It constitutes about $20 \%$ of starch. Amylose contains 200 to $1000 \alpha$-D-glucose units linked together by glycosidic linkage between C-I of one unit and C-4 of another unit. i.e. $\alpha-1,4$ glycosidic linkages.
Amylopectin is insoluble in water and constitutes about $80 \%$ starch which forms blue-violet coloured complex with iodine. It is a branched chain polymer. In amylopectin, $\alpha$-D-glucose molecules are linked together by glycosidic linkage between $C _1$ - of one unit and $C -4$ of another unit to form long chain and branching acurs by glycosidic linkage between C-I and C6 glycosidic linkage.
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