Starch is a naturally occurring polysaccharide found in plants. It's a colorless, tasteless complex carbohydrate that plants use to store energy. It's a polymer made up of glucose monomers that are joined together to form a larger structure.
There are two types of polysaccharides that make up starch:
Amylose is a polysaccharide composed of many D-glucose units. These units are connected by 1,4-glycosidic bonds. When iodine is added to a starch containing amylose, the resulting color change to dark blue or black indicates the presence of amylose. Amylose is water-soluble and can be broken down into glucose units by enzymes like α- amylase.
On the other hand, Amylopectin is a polymer that's also made up of several D-glucose molecules. It makes up about 80% of starch and is connected by α-1,4-glycosidic and α-1,6-glycosidic bonds. Unlike Amylose, Amylopectin is not soluble in water.
When starch is heated with water, the starch granules swell, producing a colloidal suspension. This suspension can easily dissolve in hot water, forming a starch paste or starch gel as it cools.
Let's delve into the differences between amylose and amylopectin.
Also Read: Carbohydrates
Here are the key differences between amylose and amylopectin:
| Amylose | Amylopectin |
| This is a linear polymer of D-glucose units | This is a branched polymer of D-glucose units |
| Makes up 20% of starch | Makes up 80% of starch |
| Soluble in water | Insoluble in water |
| Has a linear structure | Has a branched structure |
| Contains α-1,4-glycosidic bonds between the glucose units | Contains α-1,4-glycosidic bonds in the straight chain and α-1,6-glycosidic bonds at the branching points |
Also Read: The Difference between Osmosis and Diffusion
Therefore, as we can see, amylose and amylopectin, while both being components of starch, have distinct differences. Stay tuned for more information on the differences between these two polysaccharides.
What is Amylose?
Amylose is a polysaccharide made of several D-glucose units. They are linked by 1,4-glycosidic bonds. Amylose is soluble in water and can be hydrolyzed into glucose units by the enzymes α- amylase.
What is Amylopectin?
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. It is a water-insoluble fraction.
What are the main differences between Amylose and Amylopectin?
Amylose is a straight-chain polymer of D-glucose units and constitutes 20% of starch, while Amylopectin is a branched-chain polymer of D-glucose units and constitutes 80% of starch. Amylose is soluble in water, whereas Amylopectin is insoluble.