Isolation of starch from potatoes is a time taking, temperature sensitive and chemically unstable process. Combined with the isolation of starch from potatoes may result in the formation of unwanted potato proteins. This blog highlights the protocol of isolation of starch from potatoes, including the isolation of starch from the potatoes converted into flakes (defatted flakes).

This is the practical protocol for the isolation of starch from potatoes. This belongs to the 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


  • Scrape the clean surface of potatoes with a knife, cut them into pieces, 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 note the weighted deposition of starch at the bottom.
  • Pour the supernatant fluid and fill it with water containing the starch.
  • 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 the watch glass.
  • Dry it in an oven and then weigh the sample gravimetrically.

Properties of starch

  • Examine a little starch under a microscope. Note down the characteristic shape of the granules.
  • Boil a small amount of starch with water. Cools, then add iodine solution. Note the color.

Preparation of Soluble Starch

  •  Suspend three grams of raw potato in 100ml of redistilled 95% alcohol. Add 0.75ml of concentrated HCI.
  • Heat it over boiling water with a reflux condenser for twenty minutes.
  • Add at once 1 N 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.

Final words

The isolation of starch from potatoes is a time taking, temperature-sensitive, and chemically unstable process. There are three methods of obtaining starch from potatoes: the acid-treated process, the enzyme process, and the cold-water process. The acid-treated process, which is the oldest method, is the most expensive.

The enzyme process is the most widely used method today. In this process, the potatoes are steamed and then treated with enzymes. The cold-water process, used in some developing countries, involves washing the potatoes in cold water to remove starches.