food tests

• Iodine test for starch


  1. Put the food sample in the test tube

  2. Add a few drops of iodine solution using pipette

  3. If starch is present the solution will turn from orange to blue/black
• Test for Protein


  1. Add a few drops of biuret solution to the food sample

  2. Shake the solution

  3. If protein is present the solution will turn from blue to purple
• Testing for Lipids


  1. Add a few drops of distilled water and a few drops of ethanol to the test tube

  2. Gently shake the solution

  3. If lipids are present a white cloudy emulsion forms
• Ethanol


  • Highly flammable
• Testing for Sugars (glucose)


  1. Add 10 drops of Benedict's solution to the test tube

  2. Place the test tube in a beaker of hot water from a kettle

  3. Leave for 5 minutes

  4. If sugars are present the Benedict's solution will change colour from blue to (green for small amount, brick red for a lot)