Composition and structure of starch
It has 2 components -
1. Unbranched component (Amylose) -
It consists of 200 - 1,000 glucose molecules (alpha-D-glucose molecules bonded with alpha 1-4 glycosidic linkage). It is helical (each turn consists of 6 glucose units).
2. Branched component (Amylopectin) -
It consists of alpha-D-glucose molecules bonded with alpha 1-4 glycosidic linkage in straight chain and alpha 1-6 glycosidic linkage at branching points. It consists of 2,000 to 200,000 glucose molecules in straight chain and branches after every 25 glucose units.
Hello Ram Mohan,
Starch is a homopolymers by units of glucose and the storage form of carbohydrates plants.
It is synthesized by the most part of vegetable cells and stored especially in seeds (e.g. cereals and legumes), tubers (e.g. potatoes), roots (e.g. those of carrots) and some fruits (e.g. green banana).
It is present into vegetable cells and contains two types of homopoly saccarides amylose and amylopectin.
Amylose is an unbranched homopoly
saccharide formed by about 5-600 glucose units, linked by α-(1→4) glycosidic bonds.
It has a helix structure with six glucose units for turn, is soluble in water and places in the core of the starch granules.
Amylopectin represents about 80% of polysaccharide taken up with diet.
It is a branched molecule formed by thousands of glucose units, up to 50000, that, in main chain, are joined by α-(1→4) glycosidic bonds.
Thank you
