1. Testing for Organic Compounds in Foods: Protein
Using Biuret to Identify Presence of a Protein
Learning the Chemical Structure of an Amino Acid

2. Protein Testing 1. Involves an indicator, Biruet Solution
2. Biuret reacts with the amino acids in the protein
3. Solution color goes from blue to violet
4. Color change indicates a chemical reaction between the biuret and the bonds between the amino acids of a protein
Chemistry of the Biuret Test

3. The Protein Test Uses Controls
Positive Control
The experiment has the
variable. The variable is
Protein. Is there protein present?
Negative Control
Experiment
A control is a setup that yields the desired result. In the negative control, biuret is
Mixed with distilled water. Distilled water has no proteins so the color should not change as seen in the picture. Because there is not change, this is a negative result and therefore, the setup is a negative control. A positive control has protein and changes.

4. Lab Safety & Cleanup Test tubes are glass.
Biruet Solution is a base. Wash hands with water.
Goggles on at all times
Use special glassware soap and water with test tube brush to wash all test tube
Return all materials to appropriate location
Complete data table.
On back of lab, construct (5) observation statements and then write a conclusion.

5. Protein Test Results

6. Which would represent the experimental setups?

7. Proteins Are organic polymers composed of monomers called amino acids.
Strands of amino acids are called polypeptide chains. Where are the peptide bonds? They are where each individual balls touch.
Proteins are many chained structures.

8. Where is the complete protein?
Amino Acids
Polypeptide Chain
Protein made of two
Polypeptide chains
And has a specific shape
Where is the complete protein?

9. Parts of an Amino Acid

10. Each amino acid different
Colored areas make