food tests

• Benedict's test

  • test for sugars:
  • 5ml of food sample
  • prepare water bath set at 75 degrees
  • add Benedict's solution
  • place test tube in water bath for 5 mins
  • blue . green, yellow , brick red depending on how much sugar
• iodine solution test

  • test for starch
  • 5ml of food sample
  • add drops of iodine and shake lightly
• iodine solution result


  change from brick red to black or blue black
• biuret test

  • test for proteins
  • 2ml of food sample
  • add 2ml of biuret solution and gently shake
• biuret result


  change from blue to pink or purple
• sudan III test

  • test for lipids
  • 5ml of food sample
  • add 3 drops of Sudan III stain solution and gently shake
• sudan III result


  mixture becomes two layers, top layer is red as it stains lipids
• Benedict's test result

  blue to green, yellow, or brick red.