Proteins Testing for protein- the Biuret Test

Proteins are essential in the diet of all organisms. They form the main structural part of animal cells, therefore foods high in protein usually originate from animal tissue (i.e. meat, eggs an dairy products). Some plant based foods are also high in protein, especially seeds. 

Protein is required for: . growth
                                      . to repair damaged tissues 
                                      . control of chemical reactions (enzymes.) 
                                      . sending messages around the body (hormones). 
                                      . providing an emergency energy source

Protein is made up of Amino acids





Aim: To test if a sample of food contains protein

Equipment: Test Tube, sodium hydroxide (NaOH), copper sulfate (CuSO), food sample.

Method:

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


Conclusion:  The food sample was: Egg , and after adding the sodium hydroxide and copper sulfate it turned purple

For the second sample food we used milk. and after adding the sodium hydroxide and copper sulfate it turned purple. After a couple of drops of sodium hydroxide



Why did the milk and eggs change to purple? Because Both eggs and milk contained protein. And if it didn't it wouldn't turn purple but instead turn blue.