Difference between Amylose and Amylopectin

Difference between Amylose and Amylopectin

Amylose is a straight-chain polymer of D-glucose units. Amylopectin is a branched-chain polymer of D-glucose units. Amylose is a glucose polymer with long chain-like molecules, while amylopectin consists of larger highly branched molecules (1 to 6).

Amylose

• It is a linear polymer of a-glucose. It is a polysaccharide made out of several monosaccharide units. The monosaccharide involved in the formation of amylose is D-glucose.
• It is water-soluble.
• It is a straight-chain structure.
• It constitutes about 10-20% of the starch.
• It forms a blue color with iodine. It gives a dark blue/black color when an iodine solution is added.
• It has 60-300 glucose units.
• It forms by C₁ – C₄ glycosidic linkage. It has α 1-4 glycosidic linkages.
• Soluble in hot water but does not form a starch gel or paste. It does not form a gel when hot water is added.
• Hydrolysis with Enzymes – It can be hydrolyzed with α amylase and β amylase enzymes completely.

Amylopectin

• It is a branched-chain polymer of a-glucose. It is a polysaccharide that is composed of monosaccharides. Monosaccharides are D-glucose molecules. Starch contains about 80% of amylopectin.
• It is water-insoluble.
• It is a branched structure.
• It constitutes about 90-80% of the starch.
• It forms a red color with iodine. It gives a reddish-brown color when an iodine solution is added.
• It has 2000-200,000 units of glucose.
• It forms by C₁ – C₆ glycosidic linkage. It has α 1-4 glycosidic linkages and α 1-6 glycosidic linkages.
• Soluble in hot water with swelling. It forms a gel when hot water is added.
• Hydrolysis with Enzymes – Amylopectin cannot be hydrolyzed with α amylase and β amylase enzymes completely.

So, Amylose and amylopectin are two types of polysaccharides that can be found in starch granules. The main difference between amylose and amylopectin is that amylose is a straight-chain polymer whereas amylopectin is a branched-chain polymer. Amylose is usually insoluble in water, whereas amylopectin is soluble in water