Food Tests & Labellings

• Test for starch:

  ● Add drops of iodine solution

  ● Observe colour change

  ● Positive result: Blue - Black Coloured Solution

  ● Negative result: Brown Coloured Solution
• Test for proteins:

  ● Add few drops of Biuret reagent

  ● Observe colour change

  ● Positive result: Mauve or Purple Coloured Solution

  ● Negative result: Blue Coloured Solution
• Test for Reducing Sugars:

  ● Add Benedict's solution and heat it

  ● Observe colour change

  ● When reducing sugars are detected in a solution, the colour change

  happens based on the increasing concentration of sugar so blue → green → yellow → orange → red

  ● Positive result: Brick-Red Coloured Solution

  ● Negative result: Blue Coloured Solution
• Test for fats:

  ● Known as the Emulsion Test

  ● Crush the food sample in a mortar with ethanol

  ● Take a sample in a test tube

  ● Add drops of distilled water

  ● Observe a milky-white emulsion showing the presence of fats
• Labels should point directly to the image or specific part

  ● Use a ruler to draw the label line.