Food tests

• What is the first test for reducing sugars called?

  Benedict's Test
• What are the steps involved in Benedict's Test for reducing sugars?


  1. Add 5 cm³ of food sample into a test tube.
  2. Heat in a water bath at 75°C.
  3. Add 10 drops of Benedict's solution to the test tube.
  4. Place the test tube back in the water bath for 5 minutes.
  5. Observe color change: blue to green, yellow, or brick red indicates reducing sugar.
• What color indicates the presence of reducing sugars in Benedict's Test?


  Green, yellow, or brick red
• What is the second test mentioned for starch?

  Iodine Test
• What are the steps involved in the Iodine Test for starch?


  1. Add 5 cm³ of food sample into a test tube.
  2. Add a few drops of iodine solution.
  3. Gently shake the test tube.
  4. Observe color change: browny-orange to blue-black indicates starch presence.
• What color change indicates the presence of starch in the Iodine Test?


  Browny-orange to blue-black
• What is the third test mentioned for proteins?

  Biuret Test
• What are the steps involved in the Biuret Test for proteins?


  1. Add 1 cm³ of food sample into a test tube.
  2. Add 1 cm³ of Biuret solution.
  3. Gently shake the test tube.
  4. Observe color change: blue to purple indicates proteins.
• What color change indicates the presence of proteins in the Biuret Test?


  Blue to purple
• What is the fourth test mentioned for lipids?

  Sudan III Test
• What are the steps involved in the Sudan III Test for lipids?


  1. Add 5 cm³ of food sample into a test tube.
  2. Add 2-3 drops of Sudan III stain solution.
  3. Gently shake the test tube.
  4. Observe separation: a bright red layer indicates the presence of lipids.
• What indicates the presence of lipids in the Sudan III Test?


  A bright red layer
• What is the fifth test mentioned for solid lipids?


  Ethanol Test
• What are the steps involved in the Ethanol Test for solid lipids?


  1. Add food sample to a test tube and add ethanol.
  2. Extract and mix the solution with a pipette.
  3. Transfer the mixture to a second test tube containing cold water.
  4. Observe: a cloudy appearance indicates the presence of solid lipids.
• What indicates the presence of solid lipids in the Ethanol Test?


  A cloudy appearance