Food tests

• Food groups


  • Starch
  • Sugars
  • Protein
  • Fat
  • Vitamins
• Starch


  • Starch is a carbohydrate made up of long chains of glucose molecules
  • Its a food store in plants
  • Test : Iodine solution which has a brown/orange colour
  • When it is added to starch, it forms a complex with the molecules and forms a blue black colour
• Sugars


  • Reducing sugar: glucose and fructose form
  • Found in plant material
  • Test : Benedict's solution
  • If the food is solid, you will have to grind it up with water and a pestle then add it to benedict's solution
  • Heat the water bath
  • Blue - Green - Orange Brick red if reducing sugars are present
• Protein


  • Test : Biuret solution
  • Pale blue - Purple
• Fats and oils


  • Test : Ethanol test
  • Clear - Cloudy
• Vitamin C

  • Test : DCPIP
  • Add drops of DCPIP to solution
  • Count the amount of drops it takes until the solution turns blue
  • The more drops added the more vitamin C the sample contained