DEPARTMENT
OF BIOLOGY
FACULTY
OF SCIENCE & MATHEMATICS
UNIVERSITI
PENDIDIKAN SULTAN IDRIS
SBK3013
PRINCIPLE
IN BIOCHEMISTRY
LABORATORY PROJECT 3:
MEASURING VITAMIN C USING STARCH-IODINE TEST AND
MAGIC WRITING
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NAME
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MATRIC NO.
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MUHAMMAD FARIS BIN ISMAIL SAZEMI
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D20141067089
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MAYURIE PHUTHARANT A/P SURIN
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D20141067078
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NUR AFIQAH SYAHMINA BT MOHD KAMAL
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D20141067091
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GROUP: A
LECTURER’S NAME: DR. ROSMILAH MISNAN
INSTRUCTOR NAME: NUR ATIEKAH BT AZAHARI
INTRODUCTION
Experiment conducted to measure the amount of vitamin
C in different type of foods. The amount of vitamin C been measured to know how
many vitamin C we will use in the chemical proses in our body. The vitamin C
involved in our cell oxidation-reduction reaction in body. For this experiment
we use iodine to test the present of vitamin C. The vitamin C will be react
with iodine solution. When there are no more vitamin C in the solution, the
iodine will react with starch and produced bluish-black colour.
MATERIAL & PROCEDURE
(1)
Measuring Vitamin C using starch-iodine test.
1.
The food material is chopped and placed into blender.
2.
100 ml of distilled water is added to the blender.
3.
The material is blended using the highest speed until thoroughly ground.
4.
The ground extract is strained
5.
30 ml of the strained extract is measured into a 250 ml Erlenmeyer flask or
beaker.
Measuring vitamin C in the standard and
food sample:
i.
30 mL of the Vitamin C Standard placed in a 250 ml flask or beaker.
ii.
2 drops of the 0.1 M HCl is added to the flask.
iii.
5 ml of the starch solution is added to the flask.
iv.
Burette is filled with the iodine solution.
v.
The initial volume reading is recorded.
vi.
The iodine solution is added in 1 ml increments to the flask while swirling the
flask.
vii.
Iodine is added until the solution stays blue-black for 15 seconds.
viii.
The volume is recorded reading on the burette.
ix.
Step i to viii is repeated to measure the vitamin C in the food sample.
x.
The amount of Vitamin C in the food sample is calculated using this formula:
Amount
of Vitamin C in food sample = (Amount of Vitamin C in standard / volume of iodine used in standard) x Volume of iodine used in food sample
(2)
Magic writing
STEP A: IODINE SOLUTION
1.
100 ml water is poured into a 500ml-beaker.
2.
10 ml of Iodine is added to the water and stir.
STEP B:
1.
A section is cut from the notebook paper.
2.
The paper must fit inside a 500ml-beaker
STEP C: VITAMIN C SOLUTION
1.
The juice of the lemon/lime is squeeze into another beaker
STEP D:
1.
The art brush is dip into the lemon/lime juice
2.
A message is wrote on the piece of paper.
3.
The juice is allowed to dry on the paper.
4.
The paper is submerged in the iodine solution in the bowl.
RESULT
Measuring
Vitamin C using starch-iodine test.
Vitamin C standard:
The amount of iodine used = 13.7 mL, 15.4 mL
Average amount of iodine used =(13.7 mL += 15.4 mL) / 2
= 14.55 mL
Vitamin C in food sample for treated and untreated:
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Food Sample
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Amount of Iodine used (mL)
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Treated
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Untreated
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Broccoli extract
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7.2
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12
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Papaya extract
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11
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15.5
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Cooked rice
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-
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2.0
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Orange extract
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15
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16.5
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Chrysanthemum extract
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12
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33.5
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Chrysanthemum (packet drink)
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-
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0.5
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Food Sample
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Amount of Vitamin C (In 100 g)
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Treated
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Untreated
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Broccoli extract
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0.66
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1.07
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Papaya extract
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1.00
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1.40
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Cooked rice
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-
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0.18
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Orange extract
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1.33
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1.53
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Chrysanthemum extract
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1.07
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3.07
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Chrysanthemum (packet drink)
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-
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0.05
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Standard
Vitamin C before titration
Standard
Vitamin C after titration
Untreated food sample :
Papaya
extract before titration
Papaya
extract after titration
Broccoli
extract before titration
Broccoli
extract after titration
Chrysanthemum
in can (drink sample from home) before titration
Chrysanthemum
in can(drink sample from home) after titration
Treated food sample:
Food
sample before treated with heat for 5 minutes
Food
sample after treated with heat for 5 minutes
Calculation:
Amount of Vitamin C in food sample = (Amount of Vitamin C in standard / volume of iodine used in standard) x Volume of iodine used in food sample.
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For untreated orange
extract ;
=
(0.2/14.55) x 16.5 mL
=
0.23 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In 30 mL extract = (50/100) x 30 = 15 g orange
In 15 g orange = 0.23 Vitamin C
In
100 g orange = 1.53 Vitamin C
|
For treated orange
extract;
=
(0.2/14.55) x 15 mL
=
0.20 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100) x 30 = 15 g orange
In
15 g orange = 0.20 Vitamin C
In 100 g orange = 1.33 Vitamin C
|
|
For untreated papaya
extract ;
=
(0.2/14.55) x 15.5 mL
=
0.21 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.21 Vitamin C
In
100 g orange = 1.4 Vitamin C
|
For treated papaya
extract ;
=
(0.2/14.55) x 11 mL
=
0.15 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.15 Vitamin C
In
100 g orange = 1 Vitamin C
|
|
For untreated broccoli
extract ;
=
(0.2/14.55) x 12 mL
=
0.16 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.16 Vitamin C
In
100 g orange = 1.07 Vitamin C
|
For treated broccoli
extract ;
=
(0.2/14.55) x 7.2 mL
=
0.099 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.099 Vitamin C
In
100 g orange = 0.66 Vitamin C
|
|
For untreated cooked
rice ;
=
(0.2/14.55) x 2.0 mL
=
0.027 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.027 Vitamin C
In
100 g orange = 0.18 Vitamin C
|
|
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For untreated Chrysanthemum extract;
=
(0.2/14.55) x 33.5 mL
=
0.46 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.46 Vitamin C
In
100 g orange = 3.07 Vitamin C
|
For treated Chrysanthemum
extract ;
=
(0.2/14.55) x 12 mL
=
0.16 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.16 Vitamin C
In
100 g orange = 1.07 Vitamin C
|
|
For untreated Chrysanthemum
in packet (food sample from home) ;
=
(0.2/14.55)
x 0.5 mL
=
0.00687 mg/mL Vitamin C in food sample
Extract
= 50 g food sample + 100 mL H2O
In
30 mL extract = (50/100)
x 30 = 15 g orange
In
15 g orange = 0.00687Vitamin C
In
100 g orange = 0.05 Vitamin C
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Magic
writing
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Name
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Before
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After
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FARIS
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 |
 |
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MAYURI
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 |
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SYAHMINA
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DISCUSSION
Untreated
juices
For juices of untreated Broccoli extract, Papaya
extract, Cooked rice, Orange extract ,Chrysanthemum extract and Chrysanthemun
juice (from packet drink), we obtained that Chrysanthemun extract has the
highest amount of vitamin C which is 3.07mg (per 100g). Theoretically,
Chrysanthemun only have low amount of Vitamin C which is 1.4mg (per 100g).
Secondly, Orange extract has lower amount of vitamin C compared to
Chrysanthemun extract which is 1.33 mg.
Theoretically the amount of vitamin C in orange are 53.2mg (per 100g).
The value obtained differ from the theoretical value due to some errors. Next,
the amount of vitamin C obtained in papaya are 1.40mg compared to theoretically
which is 60.9mg. Next, the amount of vitamin C extract for broccoli extract is
1.07 mg/ml. Theoretically, broccoli have highest amount of vit C (per 100g)
which is 89.2mg, higher than orange and papaya. But in our experiment the value
obtained for broccoli extract are less than the amount of vitamin C in orange
and papaya. Cooked rice and chrysanthemum (packet drink) are among the lowest
amount of vitamin C which is 0.18mg and 0.05mg respectively. Theoretically both
don’t have any vitamin C content in them. The presence of vitamin C in them in
this experiment might be due to some technical errors.
The value obtained are quite differ from theoretically
value due to some errors. First and foremost, the extract obtained might have
been contaminated due to being left to the environment. Furthermore, the juices
extract are not being handle with appropriate materials for example using bare
hands to squeeze for the juices without wearing gloves. Next is, the materials
are not cleansed thoroughly before used. Last but not least, we are using the
same apparatus for all the extract, hence they might mix with each other can
cause some errors to the experiment.
Treated
juices.
Treated orange have lower amount of vitamin C which is
1.33mg compared to untreated orange. The amount of Vitamin C is lower in
treated Chrysanthemun extract which is 1.07mg compared to treated Chrysanthemun
extract. This is followed by papaya extract and broccoli extract which both
also have lower amount of vitamin C 1.00mg and 0.66mg respectively compared to
their untreated juices. The amount of Vitamin C in treated juices is lower
because high heat can reduce the vitamin C contents. This is because the
vitamin might leached out of the food into the water when we put the extract
into water bath for 5 minutes, and then degraded by the heat. Heat also can
cause the vitamin C to be oxidized.
QUESTION AND ANSWER
1.
In
our experiment, Chrysanthemun has the highest amount of vitamin C.
Theoretically, citrus juices will have most amount of Vitamin C.
2.
The
drinks had 0 amount of Vitamin C in the labels but in our experiment we
obtained a little amount of Vitamin C.
3.
Red
peppers had the most vitamin C with is 242.5mg (per 100g).
4.
Citrus
families had the most Vitamin C.
5.
The
plants that we usually eat have Vitamin C for example, broccoli.
6.
Heat
does affect Vitamin C content in food.
7.
Heat
decreases the amount of Vitamin C levels.
8.
Steaming
is recommended cooking methods to preserve vitamin in foods.
9.
We
can get more vitamins from our meals by eat locally grown food after it being
picked up.
CONCLUSION
As the conclusion, untreated Chrysanthemum extract has
the higher amount of Vitamin C which is 3.07 in 100 g. While the untreated rice
has the lower amount of Vitamin C with only 0.18 in 100 g.
REFERENCES
Ronald Eitenmiller, Lin Ye, W.O. Landen, Jr. 2008.
Vitamin analysis for the health and food
sciences. 2nd ed. Boca Raton, FL: CRC Press.
sciences. 2nd ed. Boca Raton, FL: CRC Press.
N. A. Khan and K. N. Singh. 2014. Laboratory manual of
biochemistry. New Delhi: Daya
Pub. House
Pub. House
Moran, Laurence A., Horton, H. Robert, Scrimegeour, K. G. and Perry,
Marc. 2014. Principle in
Biochemistry. 5th ed. Upper Saddle River, NJ: Prentice Hall.
Biochemistry. 5th ed. Upper Saddle River, NJ: Prentice Hall.
