Test for Proteins in Food Component – Class 7 Science Experiment

Chapter Name: Food Component

Activity Name: Test for Proteins in Food Component

Activity Description:

Test for Proteins in Food Component - Class 7 Science Experiment

This experiment is designed to test the presence of proteins in a substance using chemical reagents.

Required Items:

  1. Copper sulphate (CuSO4) – 2 grams
  2. Sodium hydroxide (NaOH) – 10 grams
  3. Water – 200 ml
  4. Test tubes
  5. Stirring rod

Step by Step Procedure:

  1. Preparation of 2% copper sulphate solution: a. Measure 2 grams of copper sulphate (CuSO4). b. Add the measured copper sulphate to 100 ml of water. c. Stir the solution well until the copper sulphate is completely dissolved.
  2. Preparation of 10% sodium hydroxide solution: a. Measure 10 grams of sodium hydroxide (NaOH). b. Add the measured sodium hydroxide to 100 ml of water. c. Stir the solution well until the sodium hydroxide is completely dissolved.
  3. Testing for proteins: a. If the substance to be tested is a solid, grind it into a fine powder or make a paste. b. Take a small amount of the substance in a test tube. c. Add 10 drops of water to the test tube containing the substance and stir well to make a solution. d. Take 10 drops of this solution and transfer them to a clean test tube. e. Add 2 drops of the prepared copper sulphate solution to the test tube. f. Add 10 drops of the prepared sodium hydroxide solution to the test tube. g. Shake the test tube well to mix the contents.

Experiment Observations:

If the substance being tested contains proteins, a change of color to violet or purple will be observed in the test tube.


  1. Handle copper sulphate and sodium hydroxide with care as they can be irritants to the skin and eyes. Wear gloves and safety goggles while handling these chemicals.
  2. Perform the experiment in a well-ventilated area to avoid inhaling any fumes.
  3. Be cautious while using glassware to avoid breakage and injury.
  4. Dispose of the chemical solutions properly according to laboratory guidelines.

Lesson Learnt from Experiment:

The experiment demonstrates a simple chemical test to identify the presence of proteins in a given substance. Proteins are an essential component of our food and are present in varying amounts in different types of food items.

This experiment provides a basic understanding of how to test for proteins and introduces students to the concept of food components and their presence in various food types.

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