How to test for vitamin C at home
Detecting vitamin C in fruits and vegetables
Wear protective gloves, a mask, and safety glasses. Perform this experiment in a well-ventilated area.
Reagents and equipment
- 3% aqueous solution of iodine in potassium iodide;
- a sheet of watercolor paper;
- a kiwi;
- an orange;
- a bell pepper;
- a knife;
- a cutting board;
- a cotton ball;
- a disposable plastic cup.
Use the cotton ball to apply the 3% aqueous solution of iodine in potassium iodide to the sheet of paper. Slice the orange, kiwi, and bell pepper. Arrange the slices on the paper, with the fresh-cut sides facing downwards. In 15 minutes, watch as the paper discolors right under the fruit slices.
Many fruits and vegetables contain ascorbic acid, also known as vitamin C. It plays a key function in biological processes in the body as a strong antioxidant. Antioxidants are compounds that absorb various free radicals (oxidizing agents that can cause mutations and destruction in cells). Iodine can be used to test vegetables and fruits for ascorbic acid content. Iodine is an oxidant, so when it reacts with ascorbic acid, it is reduced to colorless iodide ions.
C₆H₈O₆ + I₂ → C₆H₆O₆ + 2HI