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Food tests
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  • 1. Food Tests
  • 2. Test for Starch
    Place a little starch powder in a depression on a spotting tile.
    Add a few drops of iodine.
    Positive Result :
    Blue/Black colour
    Negative results:
    Browncolour
  • 3. Test for Glucose
    Take 10ml of glucose solution in a test tube.
    Add 5 drops of Benedict’s solution to the test tube.
    Lower the test tube into a water bath kept at 70oC.
  • 4. Test for Glucose
    Strong Positive Result :
    Brick Red precipitate
    Medium Positive Result
    Yellow orange precipitate
    Weak Result
    Green colour
    Negative results:
    Blue colour
  • 5. Test for proteins
    Dissolve a little milk powder in a test tube.
    Add a few drops of Biuret reagent
    Positive Result :
    Purple Colour
    Negative results:
    Blue colour
  • 6. Test for oil and fat
    Place about 1cm3 of ethanol in a test tube.
    Add a few drops of oil and mix by shaking.
    Add an equal amount of water and shake again.
    Positive Result :
    A cloudy emulsion forms
    Negative results:
    Liquid remains clear
    Note
    Food with solid fats can be tested
    by crushing them in ethanol.