Does cooking reduce the level of Vitamin C in fresh hand-squeezed fruit juice? Knowing the answer to this can help you make better nutritional choices when preparing meals. For example, avoid boiling citrus fruits to preserve the Vitamin C content of the foods you eat.
     
  MY HYPOTHESIS: I think that when you cook the fresh hand-squeezed fruit juice, it reduces the level of Vitamin C and my research supports this. Therefore, I would anticipate that the fresh juices would have a higher Vitamin C content than cooked fruit juice.  
     
  The Vitamin C detective: In order to figure out the relative content of Vitamin C in fruits, I discovered an indicator solution that can easily be made from common household ingredients. The indicator solution binds to the Vitamin C. The more Vitamin C there is in a substance, the darker the color. And presto! You now have a way to discover the difference in Vitamin C content between cooked and fresh hand-squeezed juice.  
     
  MATERIALS:  
 
  • Cornstarch
  • 2% iodine solution
  • Tap water
  • Measuring spoons
  • An eyedropper
  • Test tubes
  • A papaya, an orange and a grapefruit
  • A blender to obtain the juice from the fruits
  • A stove (make sure to ask an adult for help)
  • Pots
  
     
  METHOD:  
 
  1. Take the fresh hand-squeezed grapefruit, papaya and orange juice and boil each one separately in a different pot for precisely 3 minutes.
  2. Put them aside and let them cool.
  3. Mix 1 tablespoon of cornstarch into enough water to make a paste.
  4. To this paste, add at exactly 250 milliliters of water and boil for five minutes. Allow to cool.
  5. Add 10 drops of the starch solution to 75 milliliters of water by using your eyedropper.
  6. Add enough iodine to produce a dark purple-blue color. Now your indicator solution is ready.
  7. Put 5 milliliters of indicator solution (roughly 1 teaspoon) in a 15-milliliter test tube (one for each sample).
  8. To the test tube, use a clean eyedropper to add 10 drops of juice from your fresh fruits. For solids, pulp them in a blender and strain the juice well. Wash and clean the eyedropper for each sample. Shake well.
  9. Place all of your test tubes against a white background.
  10. Line up the tubes from lightest to darkest purple. The lighter the solution, the higher the level of Vitamin C content. That’s because Vitamin causes the purple indicator solution to lose its color.
 
     
  OBSERVATIONS:  
 
  1. I observed that when I combined the iodine with the cornstarch solution, the iodine swirled around the cornstarch solution. As well, there were tiny bubbly balls that had been created by the iodine.
  2. I saw that when I boiled the fresh hand-squeezed fruit juices, they produced tiny clear bubbles.
  3. In the test tube with the cooked (fresh hand-squeezed) orange juice, I remarked that it’s color was a dark violet while that fresh hand-squeezed orange juice was rather peach-colored, brown, blue and clear.
  4. When I was watching the test tube with the cooked grapefruit juice, I observed that the color was a clear purple-blue. In the test tube with the fresh hand-squeezed grapefruit juice, it’s was also a purple-blue color, however, the color was a bit darker.
  5. When I looked deeply in the test tube with the fresh hand-squeezed papaya juice, I saw that the color was orange and clear. It resembled watered orange juice. With the cooked papaya juice, its color was a rather pale orange-brown. Also, there were small splotches of the indicator substance because I did not shake the test tube very well.
 
     
  THE RESULTS:  
 
  1. The fresh hand-squeezed papaya juice against the cooked papaya juice: The fresh hand-squeezed papaya juice has the most Vitamin C as it is the most clear!
  2. The fresh hand-squeezed orange juice against the cooked orange juice: The cooked orange juice does not contain the most Vitamin C as it is a dark violet, compared to the orange-brown-blue colored fresh hand-squeezed juice.
  3. The fresh hand-squeezed grapefruit juice against the cooked grapefruit juice: The fresh hand-squeezed grapefruit juice does have the most clearly as it contains the most Vitamin C!
  
     
 
 
     
  CONCLUSION:
In conclusion, my hypothesis was correct as the fresh hand-squeezed juice from the fruits contain the most Vitamin C. Cooking definitely reduces the Vitamin C in the fruits I tested. So, if you want to ensure you get the maximum Vitamin C content from fruits eat them raw. Do not cook the juice from your fruits!		  
     
     
       
     
       
       
         
         
         
         
         
         
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