Orange You Glad You Have Vitamin C? Citrus Fruits: Their Absolute Vitamin C Content and How It Is Affected by Storage

Overview

Objectives/Goals Which citrus fruit contains the highest absolute vitamin C content? Is that value affected if it is covered or uncovered? My objective is to find which type of citrus fruit contains the highest absolute vitamin C content and to see if over time having the fruit juice covered or uncovered affects the vitamin C content. Methods/Materials 5cc Syringe, Plastic containers with lids, Plastic containers without lids, 500mL of 1% starch solution, Iodine, 250mg vitamin C tablets, 25mL Pipettte, 100mL Burette with stop cock, 250mL of distilled water, Juicer, 2125mL of juice of the following: Florida grapefruit, Lemons, Valencia oranges, Limes, Minello Tangerines. I used the titration method to test for the absolute vitamin C conent in the juices. Results Results were as follows: for the fresh test, the oranges had the highest vitamin C content, followed by lemons, grapefruits, tangerines, and limes. When looking at the vitamin C content in the stored juice both the covered and uncovered samples had about the same amount of vitamin C contentby day 8, though it was lost at different rates. Conclusions/Discussion Valencia oranges had the highest absolute vitamin C content when freshly squeezed. This disproved my hypothesis that the lemons would have the highest content. I have also concluded that the environment in which juice is stored can affect its vitamin C content but not as significantly as I expected. At first the covered juice lost vitamin C slower than the uncovered, however, it kept loosing each day. The uncovered lost vitamin C content very rapidly within the first few days but was then able to stabilize itself to the point that by day 8 it had basically the same vitamin C content as the covered.

Competition history

• CSEF 2004 Chemistry · Entry J0512

Resources

• CSEF project summary ↗

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