Food and nutrients

Illustrating the presence of simple carbohydrates

Illustrating the presence of simple carbohydrates

Slide

Illustrating the presence of simple carbohydrates

Objective:

Show that apples contain sugars (simple carbohydrates).

Instructions:

  • Cut up an apple into small pieces, about  5mm square.
  • Put fifteen or so pieces into a test tube.
  • Add some distilled water and several drops of Fehling's solution.
  • Heat the tube for a few minutes over a Bunsen burner.

 

Be careful! Never point the top of the test tube at someone. Fehling's solution can cause severe burns. In case of contact with your eyes, rinse them carefully with plenty of water and see a doctor. Wear suitable protective clothing, gloves and eye protection. Should there be an accident or should you feel ill, consult your doctor immediately.

 

Result:

Initially the Fehling's solution is blue.

A brick-red precipitate forms if sugar is present.