Vitamin C -- also called ascorbic acid -- is a water soluble vitamin. Your body excretes excess amounts of water soluble vitamins and does not store them. Therefore, you must consume vitamin C daily for good health. Although nearly all fruits are good sources of ascorbic acid, some fruits have higher amounts of ascorbic acid than others. You can conduct a simple experiment at home using fruit juices -- which contain the same amount of ascorbic acids as the whole fruit -- to measure the relative amount of ascorbic acid.
Step 1
Mix 2 tbsp. cornstarch with 1 tbsp. water to form a paste. Put the paste in a saucepan.
Step 2
Pour 1 cup of water in the saucepan.
Step 3
Bring the water and cornstarch mixture to a boil, then immediately reduce the heat. Allow the mixture to simmer for three minutes.
Step 4
Remove the saucepan from the heat and allow the mixture to cool for 10 minutes.
Step 5
Mix 15 drops of the cornstarch solution with 2 1/2 oz. of water in the graduated cylinder using the eyedropper.
Step 6
Add iodine solution three drops at a time to the graduated cylinder using the eyedropper. Stop adding iodine when the solution turns dark purple. This solution will be your indicator solution.
Step 7
Label each test tube with masking tape and a pen with the type of fruit juice you will be testing in it. Each fruit juice requires its own test tube. Fill each test tube with 5 ml of the indicator solution.
Step 8
Mix fruit juice three drops at a time in its labeled test tube with the indicator solution. Stop adding fruit juice to the solution when the indicator solution starts to change colors. Repeat this step for all fruit juices you are testing.
Step 9
Arrange the test tubes in order from lightest color to darkest. The test tube with the lightest color contains the fruit juice with the most ascorbic acid. The test tube with the darkest color contains the fruit juice with the least ascorbic acid.
Things You'll Need
- Fruit juices
- Water
- Cornstarch
- Saucepan
- Eye dropper
- Graduated cylinder
- Masking tape
- Pen
- Test tubes
- Iodine solution
References
- "Food and Nutrition for Every Kid: Easy Activities That Make Learning Science Fun;" Janice VanCleave; 1999
- "Contemporary Nutrition;" Gordon M. Wardlaw, et al.; 2007
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