Food Tests

  • Created by: Khadija
  • Created on: 17-02-20 15:46

Identifying food molecules a sample contains


  • Piece of food
  • Pestle and mortar
  • Beaker 
  • Distilled water
  • Glass rod
  • Funnel
  • Filter paper

1. Get a piece of food & break it up using a pestle and mortar.

2. Put ground up food in a beaker & add some distilled water.

3. Give mixture a good stir with a glass rod to dissolve food.

4. Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food.

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Use the Benedict's Test to test for reducing sugar


  • Food sample
  • Test tube
  • Water bath
  • Benedict's solution
  • Pipette
  • Test tube holder

1. Prepare a food sample & transfer 5 cm³ to a test tube.

2. Prepare a water bath set to 75°C.

3. Add about 10 drops of Benedict's solution to the test tube using a pipette.

4. Place test tube in the water bath using a test tube holder and leave it for 5 minutes. Make sure the tube is pointing away from you.

5. If the food sample contains a reducing sugar, the solution in the test tube will change from normal blue colour to green, yellow, or red, depending on how much sugar is in the food.

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Use Iodine solution to test for starch


  • Food sample
  • Test tube
  • Iodine solution

1. Make a food sample.

2. Transfer 5 cm³ of sample to a test tube.

3. Add a few drops of iodine solution and gently shake the tube to mix the contents.

4. If the sample contains starch, the colour of the solution will change from browny-orange to blue-black.

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Use the Biuret Test to test for proteins


  •  Food sample
  • Test tube
  • Biuret solution

1. Prepare food sample.

2. Transfer 2 cm³ of sample to a test tube.

3. Add 2 cm³ of biuret solution to the sample.

4. Mix the contents by gently shaking it.

5. If the food sample contains protein, the solution will change from blue to purple.

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Use the sudan test to test for lipids


  • Food sample
  • Test tube 
  • Sudan stain solution
  • Pipette

1. Prepare a food sample.

2. Transfer 5 cm³ into a test tube.

3. Use pipette to add 3 drops of sudan stain solution to test tube and gently shake the tube.

4. Sudan stain solution stains lipids. If the sample contains lipids, the mixture will seperate out onto two layers. The top layer will be bright red. If no lipids are present, no separate red layer will form at the top of the liquid.

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