Food tests

• How to test for starch?

  • Put some starch solution into a test tube.
  • add a few drops of iodine solution.
  • if starch is present iodine turns from orange/brown to blue/black
• How to test for glucose?

  • put some glucose solution into a test tube.
  • add a few drops of Benedict's solution.
  • put the test tube in a beaker of boiling water or a water bath.
  • if glucose is present Benedict's turns from blue to brick red.
• How to test for protein?

  • put some protein solution into a test tube
  • add a few drops of biurets solution to the test tube
  • biurets turns from blue to purple if protein is present
• How to test for fat?

  • add equal volumes of ethanol and water to the fat solution
  • shake the solution
  • if lipids/fats are present then the solution will become a cloudy white emulsion.