Experiment 1: Test for carbohydrates


Test the presence of carbohydrates in common food items


Materials required:

  • Food items: Bread slice, Potato slice, Soaked chickpea seeds
  • 3% iodine solution
  • Dropper


  • Place a bread slice, a potato slice and a few chickpea seeds (with seed coat removed) in separate and clean test tube
  • With the help of a dropper, place 2-3 drops of iodine solution on each item
  • Note the change in colour and record your observations


  • Blue-black colour appears on bread slice and potato slice, whereas, chickpea seeds do not show any change in colour.


  • Bread and potato contain starch which gives blue-black in colour on addition of iodine solution. Whereas, chickpea seeds do not contain starch and thus do not show any change in colour.
  • Starch is a type of carbohydrate present in many of our food items.
  • Carbohydrates are energy-yielding components of food