practicals

• what is the test for glucose?

  Benedicts solution
• what is the test for starch?

  Iodine solution test
• what is the test for protein?

  Biuret test.
• what is the test for fats? (lipids)

  The test for fats is called the Sudan III test.

  Ethanol test
• What is the Benedicts test method?

  . prepare a 5cm food sample in test tube

  .prepare 75 degree water bath

  .Add 10 drops of Benedicts solution using a pipette

  .Place tube in water and leave for 5 minutes

  . Record colour change
• Biuret test: method

  .Prepare 2cm food sample in test tube

  . Add 2cm of biuret solution and gently shake

  .Record colour change
• Iodine test: method?

  .Prepare 5cm food sample in a test tube

  .Add a few drops of iodine solution and gently mix

  .Record colour change
• Sudan III test: method?

  .prepare food sample in test tube

  .Add 3 drops of Solution using a pipette, gently shake to mix

  . Record layer change
• How do you know if a sample is containing simple sugars?

  The solution will change from blue to brick red
• How do you know if a sample contains starch?

  The solution will change from brown to blue-black
• How do you know if a solution contains protein?

  The colour will change from blue to purple
• how do you know if a sample contains lipids?

  The mixture will separate into two layers and the top layer will be bright red colour
• how do you know if the same contains fats? (ethanol test)

  The mixture will go from clear to cloudy