food tests

• what tests for lipids

  sudan iii
• what is the method when testing for lipids

  1. add 5cm cubed of food sample into a test tube
  2. use a pipette and add 3 drops of sudan iii stain solution into the tube
  3. the solution will stain the lipids and if present it will create a red layer on the top
• what tests for sugars

  benedict solution
• what is the method when testing for sugars

  1. prepare a food sample and put 5cm cubed into a test tube
  2. prepare a water bath to 75 degrees
  3. add benedict solution to the test tube using a pipette
  4. place the test tube in the water bath for 5 minutes
  5. if there is a reducing sugar the solution will turn from a blue to a green/yellow or brick red
• what are the 2 types of sugars

  reducing and non-reducing
• what is the test for protein

  biuret solution
• what are the steps to test for protein

  1. prepare a food sample and put 2cm cubed into a test tube
  2. add 2cm cubed of biuret solution to the test tube and mix contents
  3. if protein is present it will turn from blue to purple
• what is the test for starch

  iodine solution
• what are steps to test for starch

  1. make food sample and transfer 5cm cubed into a test tube
  2. add a few drops of iodine solution into a test tube and shake to mix. if starch is present it will go from a browny orange to a blue black