It is well known that vitamin C is an antioxidizer, it means that it neutralizes oxidizers. To have an idea of its antioxidizing power you can go here.

We are going to do a very simple experience allowing to know if a substance (orange juice, lemon, kiwi….) contains vitamin C.

Materials
 
-Orange juice or lemon or blister of vitamin C (in chemist's shop)
- white vinegar
- coffee filter
- potassium permanganate (in chemist's shop)
- pipette
- coffee spoon

process

-Manufacture of the permanganate solution

Dissolve a cofee spoon of potassium permanganate in a glass of white vinegar. You point out that the solution is purple. You are going to see that if your substance contains vitamin C your purple solution will become uncolored.

-Detect the vitamin C

You can begin the experience with a product which contains vitamin C as a lemon juice or a orange juice

Take a little juices of orange with your pipette and count the necessary number of drops to acquire the discoloration of the permanganate of potassium solution. You can now make the same experience with the orange juice bought in trade and compare the number of drops added with the true orange juice made at home.

Of course, the more you will have added drops of juice in the solution of potassium permanganate, the less the product will contain vitamin C The potassium permanganate is purple in the oxidized state and becomes uncolored when it is reduced. The vitamin C reduce the potassium permanganate and become uncolored. The equation of this phenomenon is the following bellow