Biuret test

Aim: To test if a sample of food contains protein.

Method:
1. Place about 2 ml of the sample into a test tube and add 5 drops of sodium hydroxide
2. Add 5 drops of copper sulfate.
3. Shake the test tube gently for side to side

Results: If the solution remains blue then there is no protein. If the solution changes to a purple colour then protein is present
 




Discussion: We dropped 5 drops of copper sulfate onto our food sample( egg white ). We shook gently it and heated it. We saw how both of the two samples turned into a lighter purple colour. This occurred because we know that both of the milk and the egg white contains protein.

Conclusion:  The milk and the egg white contains protein