1. Testing for Organic Compounds in Foods: Protein 1.Using Biuret to Identify Presence of a Protein 2.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 Negative Control Positive 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. The experiment has the variable. The variable is Protein. Is there protein present?

4. Proteins Are organic polymers composed of monomers called amino acids. Strands of amino acids are called polypeptide chains. Where are the peptide bonds? Proteins are many chained structures.

5. Amino Acids Polypeptide Chain Protein with two Polypeptide chains Where is the complete protein?

6. Parts of an Amino Acid

9. 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.