food tests

• What are the food tests covered in the video?

  Benedict's, iodine, Biuret, Sudan 3 tests
• What is the purpose of the Benedict's test?

  To test for reducing sugars
• What is the iodine test used for?

  Testing for starch
• What does a positive result in the iodine test indicate?

  Presence of starch in the sample
• What is the Biuret test used for?

  Testing for proteins
• What color change indicates the presence of protein in the Biuret test?

  From blue to pink or purple
• What is the Sudan 3 test used for?

  Testing for lipids
• What indicates a positive result in the Sudan 3 test?

  A bright red layer at the top
• What is the Emulsion test used for?

  Testing for lipids
• What color change indicates the presence of lipids in the Emulsion test?

  Cloudy white color
• What is the procedure for preparing a food sample for testing?

  • Break food using a mortar and pestle
  • Add crushed food to distilled water in a beaker
  • Stir with a glass rod until dissolved
  • Filter the solution using a funnel and filter paper
• What temperature should the water bath be set to for the Benedict's test?

  75° C
• What happens to the solution in the Benedict's test if reducing sugars are present?

  It changes to green, yellow, or brick red
• How does the preparation of the food sample differ for the Sudan 3 test compared to the other tests?

  No filtration is needed for Sudan 3 test
• What are the two types of sugars mentioned in the study material?

  • Reducing sugars
  • Non-reducing sugars
• What are the key steps in the Biuret test for proteins?

  1. Add 2 cm³ of food sample to a test tube
  2. Add 2 cm³ of Biuret solution
  3. Gently shake the mixture
  4. Observe color change from blue to pink or purple
• What are the key steps in the Sudan 3 test for lipids?

  1. Add 5 cm³ of food sample to a test tube
  2. Add 3 drops of Sudan 3 solution
  3. Gently shake the mixture
  4. Observe for a bright red layer at the top
• What are the key steps in the Emulsion test for lipids?

  1. Add food sample to a test tube
  2. Add 2 cm³ of ethanol
  3. Shake vigorously
  4. Add equal volume of distilled water
  5. Observe for a cloudy white color