Food Tests

• Food tests


  Can be used to identify the food types present in food
• Food tests


  • Starch test
  • Benedict's test
  • Biuret test
  • Ethanol test
• Starch test


  Add iodine solution
• Benedict's test


  Add Benedict's solution and heat in a water bath
• Biuret test


  Add sodium hydroxide, then a few drops of copper sulfate and shake
• Ethanol test


  Shake the fat with ethanol (alcohol), then add an equal amount of water
• Starch test


  • Iodine turns from yellow-brown to blue-black
• Benedict's test


  • The solution changes from blue to a brick-red precipitate
• Biuret test


  • The solution turns from blue to purple/lilac
• Ethanol test


  • The colourless ethanol changes to a cloudy white emulsion
• The Benedict's test is the only food test that requires heating
• The Benedict's test is the only food test in the table that is partially quantitative - i.e. it can give an estimate of the amount of sugar present
• Most foods contain more than one food type - e.g. bacon contains protein and fat
• Reagent used to test for protein


  Sodium hydroxide, then a few drops of copper sulfate