Isolation of Starch from Potatoes

This is the Practical protocol of Isolation of Starch from Potatoes. This belongs to Nutrition sciences. Now check the protocol on “Isolation of Starch from Potatoes“.

How to make potato starch

How to make potato starch?

Isolation of Starch from Potatoes


To isolate starch from potatoes


  •  Scrap the clean surface of potatoes with a knife and cut into pieces and place them in a mixture and stir for one to two minutes.
  • The grinding process is repeated three to four times until we get a homogenous suspension.
  • Then strain through fine cheesecloth into another beaker.
  • Allow standing for a few minutes and then noting the weigh deposition of starch at the bottom.
  • Pour the supernatant fluid and fill the beaker with water containing the starch in it.
  • Stir well and again allow the starch to settle down.
  • Repeat four to five times by separating starch that can be washed thoroughly.
  • Collect the white deposited starch on to watch glass.
  • Dry it in an oven and then weigh the sample gravimetrically.


  • Examine a little starch under microscopic. Note down the characteristic shape of granules.
  • Boil to a little amount of starch with water. Cools then add iodine Solution, note the color


  •  Suspend three grams of raw potato in 100ml re distilling 95% alcohol. Add 0.75ml of Concentrated HCI.
  • Heat it over boiling water with a reflux condenser for twenty minutes.
  • Add at once 1N NaHCO3Solution to neutralize 0.75ml of acid using methyl orange as an indicator.
  • Decant through a filter paper and wash with several portions of alcohol. Dry at room temperature and pressure it.


The experiment shows that starch can be extracted from potatoes having asymmetric rings and rounded rings. They show a blue color with iodine, which indicates the presence of starch.

Isolation of Starch from Potatoes
Observation of starch granules under the light microscope

The net yield of starch from potatoes in 250 grams of potatoes Solution is __________ /250 grams.

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