VITAMIN C ASSAY
Vitamin C also known as ascorbic acid which is found in citrus fruit such as orange, lemon, lime, grapefruit, grapes, guava, kiwi and many more. From the study, fresh orange juice contains the highest concentration of vitamin C among the others. Some people they thought that vitamin C (ascorbic acid) and citric acid are same but, after several reading I have found that they are not that similar. Citric acid also being found in citrus fruit and play its role as acid but it do not similar with ascorbic acid because citric acid play its role as additive while ascorbic acid as preservatives. This vitamin C also water-soluble and always being digest from human body because it does not stay in human body for a long time. So, some people might have a vitamin C deficiency that can lead to several diseases such as scurvy and so on if they are not consuming and taken a diet containing vitamin C.
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CONCEPTS
In our last lab session, we have been test the concentration of vitamin C in peeled and non-peeled guava. Usually people love to it guava without removing the guava peel. So, we handled this experiment to prove either peeled or non-peeled guava have the highest vitamin C. The redox-titration reaction was used in this experiment through the interaction between iodine-starch and vitamin C (ascorbic acid).
Methods
A. Extraction of guava juice
At first, we have chopped the guava and divide it into two parts. Half of the guava was peeled while another half left unpeeled. Then each part was weighted for 20 g to be grinded with 100ml of distilled water using a blender and then being filtrated. The debris from grounded guava was separated to get a clear extract.
B. Preparation of guava with HCl & starch solution
Next steps, both 30 ml of the guava extract was measured and transferred into 250 ml of Erlenmeyer flask separately. We have added 2 drop of the 0.1 M HCl and 5 ml of the starch solution into each flask.
C. Titration
Before the titration begun, the iodine should be filled into the burette without specific amount as long as we record the initial volume reading. Make sure to put white A4 paper under the flask to help in observation. The titration of iodine into the flask contained guava extraction for peeled guava was begun slowly until the green colour of guava turn pale green. Then this titration was repeated for the unpeeled guava. At last, the final volume of iodine used in the burette was recorded.
RESULTS
Volume of Iodine used (ml)
Peeled guava = 20 ml
Unpeeled guava = 22 ml
The concentration of Vitamin C in peeled guava is higher than unpeeled guava.
Peeled guava = 20 ml
Unpeeled guava = 22 ml
The concentration of Vitamin C in peeled guava is higher than unpeeled guava.
Idea !!
So, from the vitamin analysis we can conclude that eating unpeeled guava can give us more vitamin C for our body rather than peeled guava.