CHEMISTRY COLLOQUIUM 2013

Analysis of vitamin c (ascorbic acid) in fruit juices

Name: Ysabel DeborahTeacher advisor: Pn Betty Wong

To determine the content of vitamin c (ascorbic acid) in

different types of fruits juices

To investigate the importance of vitamin c (ascorbic acid) to

human body

To investigate the deficiency of vitamin c (ascorbic acid) in the

human bodyObje

ctive

s

Vitamin C ( Ascorbic Acid)

Structure of vitamin c/ ascorbic acid

Do different fruit juices of the same brand contain the same content of vitamin c?

The pH value of the different fruit juices from same brands was measured using a pen type pH meter to know the content of vitamin c (ascorbic acid) in each type of fruit juices

Instruments/Apparatus: Pen type pH meter, four 250ml beakers, polystyrene cup, paper towels

Materials: Different types of fruit juices of the same brand, buffer solution

Procedure

1. Four 250ml beakers are prepared and labelled A, B, C, D.

2. 200ml of the fruit juices of different flavours are poured into the following labelled beakers.

3. 100ml of buffer solution is measured and poured into a polystyrene cup. The cap of the pen type pH meter is removed and turned on. The probe end of the pen type pH meter is immersed into the buffer solution.

6. The pen type pH then is immersed into the fruit juice labelled A to obtain its pH value.7. The pen type pH meter is swirled in the fruit juice to prevent air bubbles and is left in the solution until a stable reading is displayed.8. The value shown on the pen type pH meter is recorded in a table.

9. The steps 6 to 9 are repeated using the other sample of fruit juices in beaker B, C, and D.

4. The pen type pH meter is swirled in the buffer solution to prevent air bubbles and is left in the solution for at least 30 seconds until it reads pH 7.

5. The pen type pH is rinsed under running water and excess liquid is dried with a paper towel.

Results:A

(Apple juice)B

(Orange juice)

C(Guava juice)

D(Grape juice)

Reading 1 3.1 3.1 3.2 3.3

Reading 2 3.1 3.0 3.2 3.3

Results:

A B C D2.85

2.92.95

33.05

3.13.15

3.23.25

3.33.35

3.1 3.1

3.2

3.3

3.1

3.0

3.2

3.3

Reading 1 Reading 2

Food with high amount of vitamin c (ascorbic acid)

Fruits Vegetables

Benefits of vitamin c (ascorbic acid) to human body

Growth And Repair Of Tissues

Prevent the build-up of radicals

Maintains healthy bones andteeth

Deficiency of vitamin c (ascorbic acid)

Anaemia

Bleeding gums

Nose bleedingScaly skin

Weight gain

Conclusion• All the fruit juice A, B, C, D, had the same vitamin C

content due to the insignificant difference in the pH. • Form our observation of the nutritional information of

the fruit juices on the back of the box, our conclusion was also strengthened. We saw that all the vitamin C contents in the fruit juice were the same (39mg) for juice A, B, C and D.

• Different types of fruit juice of the same brand do contain the same content of vitamin C. The vitamin C content is not affected by the type of fruit juice if the fruit juice came from the same brand.

Bibliography

1. http://www.nlm.nih.gov/medlineplus/ency/article/002404.htm

2. http://www.ehow.com/how_7900217_use-pen-ph-meter.html

3. http://www.ehow.com/how_5494207_calibrate-ph-pen.html

4. http://nutritiondata.self.com/foods-009101000000000000000-4w.html?

APPRECIATION

We would like to express our heartfelt gratitude especially to:

1. Pn Betty Wong, our beloved teacher advisor for giving us a lot of guidance and advices. Not only that, we will not forget the help she gave us in solving the problems we encountered throughout the research.

2. The school computer lab, for following us to access the Internet with

ease in order to obtain the information that we were looking for. Besides that, we would also like to thank the school library for providing us with a wide range of reading materials.

3. All parties that also succeeded this research.

 © ysabeldeborah@gmail.com