Starch is a colourless and odourless polysaccharide that is found in plants as stored carbohydrates. It is a polymer of glucose monomers that are linked with each other to form polysaccharide.
Starch is composed of two types of polysaccharide molecules:
Amylose and Amylopectin
Amylose is a polysaccharide made of several D-glucose units. They are linked by 1,4-glycosidic bonds. When iodine is added to starch, the colour changes to dark blue or black due to the presence of amylose present in the starch. Amylose is soluble in water and can be hydrolyzed into glucose units by the enzymes α- amylase and β-amylase.
Amylopectin is a polymer of several D-glucose molecules. 80% of amylopectin is present in starch. Amylopectin molecules are linked by α-1,4-glycosidic bonds and α-1,6-glycosidic bonds. When iodine is added to starch, it gives reddish-brown appearance due to the presence of amylopectin. It readily dissolves in hot water. On cooling, it forms a starch paste or starch gel.
Let us discuss the difference between amylose and amylopectin.
Also Read: Carbohydrates
Difference Between Amylose and Amylopectin
Following are the important difference between amylose and amylopectin:
|It is a straight-chain polymer of D-glucose units||It is a branched-chain polymer of D-glucose units|
|Constitutes 20% of starch||Constitutes 80% of starch|
|Solubility in water is less||More soluble in water|
|Straight chain structure||Branched structure|
|Amylose stains blue with iodine||Amylopectin stains reddish-brown with iodine|
|Soluble in hot water without swelling||Soluble in hot water with swelling|
|Does not form a gel when hot water is added to it||Forms a gel when hot water is added to it|
Also Read: Difference between Osmosis and Diffusion
Thus we see how amylose and amylopectin are different from each other. For more information on the difference between the two, keep visiting BYJU’S website or download BYJU’S app for further reference.