RP04 food tests

• what is the aim of this practical?

  foods that contain carbs, lipids and proteins
• METHOD test for starch

  put some of the food sample into test tube

  add a few drops of IODINE solution

  colour changes from BROWN to BLUE-BLACK
• starch summary


  iodine

  brown to blue black
• METHOD test for sugar

  place a small food sample into test tube and add water

  add a few drops of BENEDICTS SOLUTION

  place the test tube in a HOT water bath for 10 minutes at around 80oC

  Colour changes from blue to brick red
• sugar summary

  BENEDICTS SOLUTION

  blue to brick red
• METHOD test for lipids

  Put a small food sample into a test tube

  Add a few drops of ethanol

  Shake and leave for a minute and add water

  Goes CLOUDY
• Lipids summary 


  ETHANOL

  Clear to cloudy
• why is ethanol dangerous to use?

  highly flammable
• METHOD test for protein


  small food sample in test tube

  add 1cm^3 of Biuret solution OR add 1cm^3 of sodium hydroxide and then add a few drops of copper sulfate

  blue to purple
• Protein summary 


  Biuret solution

  Blue to purple
• why is Biuret solution dangerous?

  copper sulfate; poisonous

  sodium hydroxide; corrosive