What is Amylose vs Amylopectin?
Starch is a nutritional compound stored in plants as carbohydrates. It consists of heteropolysaccharides such as amylose and amylopectin.
The article provides the core difference between amylose and amylopectin. Take the time to read through it for deeper understanding.
Amylose is a linear polymer of D-glucose units. The polysaccharide is made up of several monosaccharide units.
The combination of monosaccharide units results in the formation of amylose of D-glucose. It normally contains about 20-25% of starch content. α 1-4 glycosidic linkage is a chemical bond found between glucose monomers.
This is because the OH group attached to the first carbon of a glucose molecule is removed along with an H atom attached to the fourth carbon of another glucose molecule in the formation of amylose.
The process is known as condensation reaction since it deals with the removal of OH group and H atom together forms a water molecule.
The testing of starch in amylose is done by adding a few drops of iodine solution to the starch content. The colour tends to change to black or dark.
Amylose is soluble in water and it can be hydrolyzed into glucose units by enzymes such as α amylase and β amylase.
Amylopectin is a branch of chain polymer of D-glucose units. The polysaccharide normally contains several units of monosaccharide.
The starch content of amylopectin is about 80% and the molecules are bonded together by a chemical bond known as α 1-4 glycosidic linkages and α 1-6 glycosidic linkages.
These α 1-6 glycosidic linkages cause the branched structure of amylopectin. The glucose molecules are bonded to each other through the fourth carbon atom as well as the sixth carbon atom.
The present of amylopectin is tested by the use of iodine solution which normally changes to reddish-brown colour.
Amylopectin is less soluble in water but quite soluble in hot water. It comes from starch gel or pastes when it cools down.
Comparison Chart: Amylose Vs Amylopectin
|Meaning||It is a straight-chain polymer of D-glucose units.||It is a branched-chain polymer of D-glucose units.|
|Percentage in Starch||20%||80%|
|Structure||Linear chain polymer||Branch chain polymer|
|Glycosidic Bonds||Has α 1-4 glycosidic linkages||It has α 1-4 glycosidic linkages and α 1-6 glycosidic linkages.|
|Solubility in Water||Less soluble||Quite soluble|
|Colour Change with Iodine||Dark blue-black||Reddish-brown color|
|Hydrolysis with Enzymes||Tend to be hydrolyzed with α amylase and β amylase enzymes completely.||It cannot be hydrolyzed with α amylase and β amylase enzymes completely.|
|Formation of Gel||Does not form a gel when hot water is added||Forms a gel when hot water is added.|
|Energy Content||Great storage system for energy.||It only stores a small amount of energy.|
|Units Of Glucose||It has 300-several thousand units of glucose.||Has 2000-200,000 units of glucose.|
Core Differences Between Amylose and Amylopectin
- Amylose has about 20% of starch while amylopectin contains 80% of starch.
- Amylose is a linear chain polymer while amylopectin is a branch chain polymer
- Amylose change color to dark blue-black with iodine while amylopectin change to reddish-brown color
- Amylopectin is less soluble in water while amylose is more soluble in water.
- Amylose is less soluble in hot water while amylopectin is soluble in hot water
- Amylose has 300-several thousand units of glucose whereas Amylopectin has 2000-200,000 units of glucose.
- Amylopectin only stores a small amount of energy while Amylose is a great storage system for energy.
- Amylose has α 1-4 glycosidic linkages whereas amylopectin has α 1-4 glycosidic linkages and α 1-6 glycosidic linkages.
Similarities between Amylose and Amylopectin Content in Starch
- Both have starch granules
- Both have composed of D-glucose units.
- Both are polysaccharide molecules
- Both molecules have α 1-4 glycosidic linkages
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Amylose and amylopectin are types of polysaccharides of starch granules. However, they have structural differences and similarities.
The core difference between amylose and amylopectin highlighted above are worth reading for deeper understanding.
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