Biochemical tests

• Describe test for reducing sugars

  • Add food sample and grind up
  • Add Benedict’s reagent
  • Heat gently
  • Will go from blue to orange
• Describe the test for a non-reducing sugar

  • Add Benedict’s and it will stay blue if non-reducing
  • Boil with an acid (HCl)
  • Neutralise with Sodium Hydrogencarbonate
  • Re-test with Benedict’s and heat
  • Will turn orange
• Describe the test for lipids

  • Add ethanol to sample and shake
  • Add water and shake
  • White/milky emulsion forms
• Test for Amylase (a protein)

  • Add Biuret reagent
  • Will change from blue to purple
  • Add starch and test for absence of starch