Ascorbic acid, also known as vitamin C, is an essential water-soluble vitamin that can only be obtained through your nutritional intake. Vitamin C is important for a number of biological processes, including immune function, cardiovascular health, collagen production, wound healing and bone health. It has also been implicated as a protective agent against certain diseases including hypertension, heart disease and cancer. The amount of vitamin C in your food can vary, depending upon the source, preparation and storage of the vitamin C source. You can determine the relative amount of vitamin C content in food.
Step 1
Dissolve cornstarch in the saucepan. Add approximately 2 to 3 tbsp. cold water to 1 tbsp. cornstarch and stir to make a paste.
Step 2
Boil the cornstarch solution. Add approximately 250 ml cold water, mix thoroughly, and bring it to a boil in a small saucepan over medium to high heat. Reduce heat and simmer for five minutes. Remove from heat and allow the solution to cool for five minutes.
Step 3
Dilute the cornstarch solution. Use an eyedropper to add approximately 10 equal-sized drops of the cornstarch solution to 75 ml distilled water.
Step 4
Mix in iodine. Adding drops, mix in the 2 percent iodine solution to the diluted cornstarch solution until a deep, dark purple color has developed. This is your indicator solution.
Step 5
Measure fruit juices. Add 2 to 5 ml cornstarch-iodine indicator solution to a new test tube. Add one to 15 drops of your desired fruit juice until you see a color change. Set aside. To measure the difference between fruit juices, add the same amount of drops to another test tube with the same amount of indicator solution. The lighter the solution, the more the vitamin C.
Step 6
Measure different foods. Use a blender to puree the food and strain the liquid with cheesecloth. Test the blended liquid the same as you did with the fruit juice.
Tips and Warnings
- Make sure you use the same amount of indicator solution and food product between successive tests to ensure that you don't get false results between foods. Cold water is the key to dissolving cornstarch initially; hot water will make it clump.
- Avoid accidental poisoning by iodine by storing it away from food products and out of the reach of children.
Things You'll Need
- Distilled water
- Cornstarch
- Saucepan, small
- 2 percent iodine solution
- Eye dropper
- Graduated cylinder, small
- Blender
- Cheesecloth
- Test tubes
- Fruit juices
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