Question

How can we test presence of proteins in food​

Answer 1

Protein Test Materials

Calcium oxide (sold as quicklime in building supply stores)

Red litmus paper (or another method to test pH)

Water

Candle, burner, or another heat source

Eye-dropper

Test tube

Milk or other foods to test

Procedure

Because milk contains casein and other proteins, it's a good food to start your testing with. Once you understand what to expect from testing milk, you can examine other foods.

Add a small amount of calcium oxide and five drops of milk to a test tube.

Add three drops of water.

Dampen the litmus paper with water. Water has a neutral pH, so it should not change the color of the paper. If the paper does change color, start again using distilled water rather than tap water.

Carefully heat the test tube over a flame. Hold the damp litmus paper over the mouth of the test tube and observe any color change.

If protein is present in a food, the litmus paper will change color from red to blue. Also, smell the test tube: If protein is present, you should be able to detect the odor of ammonia. Both of these indicate a positive test for protein. If protein is not present in the test sample (or is in insufficient concentration to produce adequate ammonia during testing), the litmus paper will not turn blue, resulting in a negative test for protein.

Answer 2

Answer:

Because milk contains casein and other proteins, it's a good food to start your testing with. Once you understand what to expect from testing milk, you can examine other foods.

1.Add a small amount of calcium oxide and five drops of milk to a test tube.

2.Add three drops of water.

3.Dampen the litmus paper with water. Water has a neutral pH, so it should not change the color of the paper. If the paper does change color, start again using distilled water rather than tap water.