Testing for Protein - the Biuret Test

Aim; To test if a sample of food contains protein

Equipment: Test type, sodium hydroxy(NaOH), copper sulfate(CuSO4), food sample

Method: 1. Place about 2ml 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 from side to side.

Results: egg went from yellow to light blue and then purple.
Milk went white to purple.

Conclusion: Changes proteins molecule means changing colour.