food tests

• What are the 7 food groups

  carbohydrates, proteins, lipids, vitamins, minerals, fibre, water
• What do you use to test for starch?

  Iodine
• when there is a positive test for starch what colour does iodine change from?

  yellow/brown to Blue/BLack
• what is used to test for reducing sugar?

  Benedict's solution
• what is the method for testing for reducing sugars?

  add a few drops of benidicts solution into a test tube and heat into a water bath
• when there is a positive test for reducing sugars what is the colour change?

  blue to brick red/orange
• what is used to test for protein?

  Biuret solution
• what is the positive result when testing for protein?

  blue to purple
• what is used to test for fat?

  Ethanol emulsion test (clear)
• what is the method for testing for fat ?

  add 2cm3 of ethanol to a food dissolved in fat (filter if needed)at 2cm3 of water into test tube and then shake the test tube
• what is the positive test for fat?

  milky white emulsion forms