food tests

• test for sugars

  1. crush up food and place in a beaker of water - stir to dissolve it
  2. filter out using a funnel and filter paper
  3. transfer 5 ml of the filtered solution to a test tube
  4. heat a water bath at 75 degrees
  5. add 10 drops of benedict’s solution into the test tube and place inside the heated water bath
  6. if sugars are present then benedict's solution will change from blue to orange
• test for starch (carbohydrate)

  1. crush up food and place it in a beaker with water - stir to dissolve it
  2. filter out using a funnel and filter paper
  3. place 5 ml of filtered solution into a test tube
  4. add a few drops of iodine solution
  5. if starch is present iodine solution will turn from orange to blue / black
• test for protein

  1. crush up food and add to a beaker of water - stir to dissolve it
  2. filter out using a funnel and filter paper
  3. add 2 ml of the filtered solution to a test tube and add another 2 ml of biuret solution
  4. shake it
  5. if protien is present then biuret solution will change from blue to pink
• test for fats/ lipids

  1. crush food up in a beaker of water - stir to dissolve
  2. filter out using a funnel and filter paper
  3. add 5 ml of filtered solution to a test tube
  4. add 2 ml of ethanol
  5. shake it
  6. add 2 ml of water
  7. if fats are present it should turn a cloudy white
• food tests

  1. fats / lipids - ethanol turns cloudy white
  2. starch / carbohydrates - iodine turns from orange to black
  3. protien - biuret turns from blue to pink
  4. sugars - benedict's turns from blue to orange
• biuret test

  Test for protein

  If protien is present it will change from blue to pink
• benedicts test

  test for sugars

  if sugars are present it will change from blue to orange
• iodine test

  test for starch

  if starch is present it will change from orange to blue / black
• ethanol test

  test for fats

  if fats are present it will turn cloudy white
• what must you do to prepare a food test solution ( first steps of any food test)

  1. crush up food and add to a beaker of water
  2. stir to dissolve
  3. filter using a funnel and filter paper
  4. add filtered solution to a test tube