REQUIRED PRACTICAL 4: FOOD TESTS

• test for sugar

  • put 2cm(^3) of glucose solution in test tube
  • add an equal volume of benedict's solution
  • put hot water (NOT BOILING) into beaker
  • test tube in beaker for 5 minutes
• test for starch

  • put approximately 2cm(^3) of starch solution in a test tube
  • add a few drops of iodine solution
  • record colour change
• test for protein

  • put approximately 2cm(^3) of egg white solution in test tube
  • add 2cm(^3) of biuret solution into test tube, shake gently to mix
  • record colour change
• test for fat (fats-emulsion)

  • add ethanol to a grinded food sample (this dissolves the fat if present)
  • add water
  • record if cloudy (white emulsion) it's positive, colourless if negative