Eat 'Yer Fruits & Veggies
by Jessie B.
2nd Place (Tie) - Chemistry
QUESTION - What food source has the most Vitamin C?
RESEARCH - Vitamin C is essential for growth in the human body. It is necessary if you want healthy teeth, bone, and red blood cell formation. Vitamin C is an important anti-oxidant that helps protect against cancers, heart disease, stress and it helps maintain a healthy immune system. During the research process the vitamin C content of different fruits and vegetables was looked at from several different sources. Each source had a different level of Vitamin C content for the same fruit or vegetable. In some sources broccoli was listed as having the highest Vitamin C content while in others strawberries had the highest listing. It was finally determined that some of the sources studied listed raw fruits and vegetable while other listed cooked. As we know cooking destroys vitamin C content so for the purpose of this experiment I will test only raw fruits and vegetables and try to determine which has the most vitamin C. Based on most of the research broccoli has a lot of vitamin C.
HYPOTHESIS - Broccoli will have more Vitamin C than oranges, grapefruit, strawberries, green peppers and potatoes.
EXPERIMENT - The materials used were Iodine, Cornstarch, Water, Eyedropper, 15-milliliter medicine cup, Blender, Glass Jar, and a Cooking Pot. The fruits and vegetables tested were Oranges, Potatoes, Grapefruit, Strawberries, Broccoli, and Green Peppers.
The steps in the experiment were
1. Mix 1 tablespoon of cornstarch into enough water to make a paste.
2. To this paste, add 250 milliliters of water and boil for 5 minutes.
3. Using an eyedropper add 10 drops of the starch solution to 75 milliliters of water
4. Add 10 drops of iodine to the starch solution to produce a dark purple-blue color. This is the indicator solution.
5. Put 5 milliliters of indicator solution in each 15-milliliter medicine cup.
6. Cut up fruit or vegetable being tested.
7. Blend samples in blender to extract juice
8. Add 10 drops of juice from the fruit or vegetable being tested to the test tube.
9. Clean the eyedropper between each test.
10. Let samples sit for 45 minutes. Note speed with which solution fades.
11. Hold the test tube against a white paper.
The lighter the solution, the higher the Vitamin C content.
12. Take picture of each test.
ANALYSIS - It should be noted that all tests were done in the same way There were three tests done, taking a sample from three of each fruit and vegetable tested. While doing my experiment I observed the following; first I tested potatoes. I took three different samples from 3 different potatoes. The iodine solution did not clear very much. There was still a purple color after 45 minutes of sitting. Next I tested oranges. Just like the potatoes the iodine solution did not clear very much at first but after sitting for 45 minutes it became color that was lighter than the potatoes. Then I tested grapefruit; it was slower to turn than oranges so I listed oranges, grapefruit and potatoes. The next batch tested were strawberries, green peppers and broccoli. The strawberries and green peppers turned the iodine solution clear immediately; no waiting was really necessary. The broccoli was slower to turn than strawberries and green peppers. In conclusion it appeared that the order in which the highest to lowest vitamin C content went as follows, green peppers, strawberries, broccoli, oranges, grapefruit and potatoes.
DISCOVERY - In this experiment I learned how to mix chemicals in precise amounts then test a variety of fruits and vegetables. What I thought was going to have the highest vitamin C content, broccoli actually by my experiment came in third with vitamin C content. I wouldn't have guessed that green peppers had so much vitamin C as to change the solution immediately. While doing this experiment I observed when you put the juice of the fruit or vegetable in the solution the iodine color dissolves depending on how much Vitamin C is in each fruit or vegetable. The more vitamin C, the lighter the solution. Also the higher the vitamin C content the quicker the solution will clear. I also have an appreciation for how important a variety of fruits and vegetables are in our diet.
BIBLIOGRAPHY -
Health Garden. Fruit and Vegetables Compared and ranked by Vitamin C content. Revised 2005.www.health-garden.com/vitamin-c-
Dr. J. D. Decuypere. Vitamin Chart. Revised 2002-2008 www.healthalternatives2000.com/vitamins-nutrition-chart.html
Lenntech. Vitamin C content in Fruits and Vegetables. Revised 1998-2008 www.lenntech.com/fruit-vegetable-vitamin-content.htm
Science Made Simple. Science projects about nutrition and health.Revised 2006.http://www.sciencemadesimple.com/nutrition_projects.html
