amylose & amylopectin

1. Isolation of amylose and
amylopectin from starch
Dr .Waseem Safdar (Assistant Professor) NDBS NUMS
Biochemistry-II
(Practical-2)

2. Content
Introduction & Principal
Materials
Method
Result
Interpretation
Conclusion
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

3. Introduction
Starch is a colorless and odorless solid substance that can be found in
plants as their storage carbohydrate.
In starch a number of glucose monomers are bound to each other
through glycosidic bonds in order to form polysaccharide.
Starch is composed of two types of molecules: amylose and amylopectin.
Amylose is formed of several glucose units arranged in a linear manner.
Amylopectin is formed from several glucose units arranged in a branched
manner.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

4. Difference
Amylose: Amylose is a straight chain polymer of D-glucose units.
Amylopectin: Amylopectin is a branched chain polymer of D-glucose units.
Amylose: Amylose content in starch is about 20%.
Amylopectin: Amylopectin content in starch is about 80%.
Amylose: Amylose is a straight chain structure.
Amylopectin: Amylopectin is a branched structure.
Amylose: Amylose has α 1-4 glycosidic linkages.
Amylopectin: Amylopectin has α 1-4 glycosidic and α 1-6 glycosidic linkages.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

5. Difference (cont…)
Amylose: Amylose is less soluble in water.
Amylopectin: Amylopectin is more soluble in water.
Amylose: Amylose gives a dark blue/black color when iodine solution is added.
Amylopectin: Amylopectin gives a reddish brown color with iodine
Amylose: can be hydrolyzed with α amylase and β amylase enzymes completely.
Amylopectin: cannot be hydrolyzed with α and β amylase enzymes completely.
Amylose: Amylose does not form a gel when hot water is added.
Amylopectin: Amylopectin forms a gel when hot water is added.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

6. Principal
The aim of this experiment is to separate the two fractions of starch, amylose
and amylopectin.
It is well known that potato starch granules are formed of a matrix of
amylopectin throughout amylose is dispersed.
Under mild basic conditions, the amylose leaches out leaving the
amylopectin network unaltered.
Several modified potato starches with slow digestibility are being developed
that may provide nutritional benefits for humans.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

7. Materials
• Potatoes (4-5)
• NaCl
• NaOH
• HCL (0.6 M)
• 1-butanol
• Centrifuge
• Potato peeler/shredder
• Conical flasks
• 2 Glass Beaker (1000 mL)
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS
• Heating plate
• Distilled water
• Test tubes (6)
• Electrical balance (0.1 g)
• Measuring cylinder (100 ml, 250 ml)
• Iodine solution

8. Methods
• Grind a Potato into 40% aqueous slurry of potato prepared by using
distilled water in a conical flask.
• Then mix 20ml of 40% aqueous slurry of potato with 60ml of NaOH (40%)
• swirl gently and leave 5 minutes for suspension separation
• After 5 minutes, add 20ml of 5% NaCL in 0.6M HCL and mixed gently
• centrifuge at 10,000rpm for 15 minutes
• supernatant will be seeped in different conical flask,
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

9. Methods
• wash pellet with 20ml of 1% of NaCL overnight.
• centrifuge at 10,000 revolutions per minute (rpm) for 15 minutes,
• discard supernatant and keep amylopectin pellet.
• Amylose precipitated with 1-butanol from the original supernatant that
separated in the different conical flask and stands for overnight the same
as amylopectin pellet.
• Then collect amylose after centrifugation at 5,000 rpm for 15 minutes.
• Add Two drops of iodine solution to amylose and amylopectin respectively.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

10. Results & interpretation
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS
Time Iodine Test
Amylose Color Amylopectin Color
0-1 minutes Blue black Reddish brown
2-3 minutes Pale Blue black Pale Reddish brown
4 minutes Retain original sample color Retain original sample color

11. Conclusion
Conclusively, Starch is a highly hydrophilic polymer that consists of linear
amylose and highly branched amylopectin. Starch can be easily isolated
using environmentally friendly processing technologies like sedimentation
phase done in isolation of amylose and amylopectin from potato starch in this
experiment.
Dr .Waseem Safdar Biochemistry-II (MIC-635) NDBS - NUMS

12. THANKS