Testing for Protein- the Biuret Test- Science

Testing for Protein- The Biuret Test

Aim: To test if a sample of food contains protein.
Equipment: Test tube, sodium hydroxide ( NaOH ), copper sulfate ( CuSO4 ), food sample.

Result: If the solution remains blue, then no protein is present. If the solution changes to a purple color then protein is present in the sample.



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

Result:
egg: went from white to light blue to purple because it shows protein.
milk: went from white to light blue to light purple because it shows protein.

Conclusion: 
 The egg changes to purple and the milk changes to light purple because it shows protein. The reason why the milk changes to light purple because of the milk.



Aim: To test if a sample of food contains protein.
Equipment:Test tube, sodium hydroxide ( NaOH ), copper sulfate ( CuSO4 ), food sample.

Method:
Protein:
1.) Place about 2ml of the sample into the test tube and add 5 drops of  NaOH
2.) Add 5 drops of copper sulfate
3.) Shake the tube gently side to side

simple:
1.  Place about 2mL of the sample into test tube and add 5 drops of sodium hydroxide.
2. Heat with a bunsen burner until it changes color.

complex:
1.)  Place about 2mL of the sample into test tube 
2.) add 305 drops of iodine and mix

Results:
Protein-
simple-
complex-
Conclusion: