For this experiment A range of fruit juices
I will be using Orange juice, Apple juice, Pineapple juice and Pink Grapefruit juice.
Standard 1% Vitamin C Solution
1% DCPIP solution
Pipette, syringe or burette to measure volumes accurately
Standard laboratory glass ware and apparatus
Hypothesis
The fruit juice that will contain the most vitamin C will be orange juice; this is because it has been known as one of the primary sources of vitamin C.
Process
Firstly, I will put 1ml of DCPIP measured out using a syringe into a test tube. I will then add the vitamin C drop by drop using a burette into the test tube until the DCPIP’s original colour disappears. After that, I will record the exact amount of vitamin C used to change the colour. I will repeat this 3 times to develop a good set of results and produce an average, with the average I will be able to work out the content of vitamin C in each fruit juice. I will now repeat this using the fruit juices and record how many millilitres of vitamin C used to change the colour.
Results (DCPIP)
- 9ml of vitamin C, before it went clear the final measurement was 8.4ml – 0.6ml used to change colour
- 9ml of vitamin C, before it went clear the final measurement was 8.3ml – 0.7ml used to change colour
- 9ml of vitamin C, before it went clear the final measurement was 8.9ml – 0.1ml used to change colour (this may have happened because the test tube was not cleared out properly or the DCPIP used was an older batch)
- 9ml of vitamin C, before it went clear the final measurement was 8.6ml – 0.4ml used to change colour
- 9ml of vitamin C, before it went clear the final measurement was 8.6ml – 0.4ml used to change colour
Results (fruit Juice)
Apple Juice (100% from concentrate)
-
0.5ml used to change
- 0.4ml used to change Starting point on Burette 37ml
- 0.2ml used to change
Pink Grapefruit Juice (100% from concentrate)
-
0.2ml used to change
- 0.3ml used to change Starting point on Burette 37ml
- 0.3ml used to change Colour changed to a pink
Pineapple Juice (100% from concentrate)
- 0.1ml used to change
- 0.2ml used to change Starting point on Burette 37ml
- 0.3ml used to change Colour changed to a cloudy pink
Orange Juice (100% from concentrate)
-
0.1ml used to change
- 0.2ml used to change Starting point on Burette 37ml
- 0.3ml used to change Colour changed to a pale orange
Plant sources
Though plants are generally a good source of vitamin C, the quantity in foods of plant derivation depends on: the exact selection of the plant, the soil state, the climate in which it grew, the duration of time since it was picked, the storage conditions, and the process of preparation.
I have obtained the following information on vitamin C content in fruit from Wikipedia.
This table indicates the amount of Vitamin C (milligrams) on average per 100g of fruit.
From the averages here I can clearly see that orange provides the most Vitamin C, 7 times more than an average apple. However there were twenty-four other fruits and vegetable that contained considerably more than orange, surprisingly broccoli was one of them containing 90mg per 100g.
Comparing my results with the ones in the table I can see that I have successfully proved that the orange juice has the highest vitamin C content. Also from my results I can see pineapple juice is the second highest in concentration and that the apple juice provides the least. My results are identical with the information in the table.
I can now also tell that I correctly performed the experiment and proved my hypothesis correct.
Conclusion
From the question I was given at the beginning, I have found out that the hypothesis I drew up was accurate. The orange juice provided 30mg3cm vitamin C content whereas the apple provided only 16.2mg3cm. I believe that using the DCPIP on the individual juices three times was exceptionally helpful as it gave me reasonably accurate results.
