Food Tests: Protiens and Lipids

Question 1

How do we test for protiens?

Answer 1

• Take 2cm^2 of food solution + add 2cm^3 of biuret solution (blue colour).
• ## Protien is present: Changes from blue to purple/lilac.

Question 2

How do we test for lipids and fats? Information on food solutiom.

Answer 2

• We still grind our food with distilled water using a mortar and pestle.
• BUT: We do not filter the solution.
• ## Because: Lipid molecules can stick to filter paper.

Question 3

What is the method for testing fats and lipids?

Answer 3

• 2cm^3 of food solution into test tube.
• Add a few drops of distilled water + few drops of ethanol.
• Gently shake the solution.
• Lipids present= White cloudy emuision forms.
• Ethanol is very flammable so make sure no flames are present.