Vitamin C besides known as ascorbic acid is synthesized by works tissues, every bit good as mammals except guinea hog and Primatess ( including adult male ) . Experiment by Lind in 1753 were the first to demo the powers of vitamins when he examined that the slayer disease scorbutus could be prevented or quickly cured by feeding patients fresh citrous fruit fruits. Many nutrients in this universe contain vitamin C.

Ascorbic acid is a powerful cut downing agent giving up 2 H atoms to go dehydroascorbic acid.

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The usual method for the finding of ascorbic acid content is based upon its stableness to cut down the dye 2-6 dichlorophenol indophenols ( D.C.P.I.P ) to a colourless compound. The concentration of D.C.P.I.P is set by an international criterion.

The mass of ascorbic acerb equivalent to 1 cm? of D.C.P.I.P is given as 0.05 milligram ( International Data Standard July 1980 )

RESEARCH Question: What is the consequence of cooking on the sum of vitamin C in nutrients?

HYPHOTESIS: If the cookery clip for the lemon juice is longer, than the concentration of ascorbic acid contain in the lemon juice will go lower.

This is because, when much clip is spent to boil the lemon juice, the vitamin C will destruct and as the consequence it lessens the concentration of the ascorbic acid. Therefore, higher volume of solution* is needed to decolor the bluish coloring material of the D.C.P.I.P solution.

## Variable:

Mugwump: The clip period for the lemon juice to be cooked. Those lemon juices are cooked for three different clip period 0 minute ( fresh lemon juice ) , 10 min and 60 minute ( 1 hr ) .

Dependant: The concentration of ascorbic acid in the lemon juice. The concentration is measured by ciphering the volume of solution* used to cut down the bluish coloring material of D.C.P.I.P to colourless. By utilizing a burette, the mixture of lemon juice, distilled H2O and glacial acetic acid is titrated into the D.C.P.I.P solution. The volume is noted when the bluish coloring material alteration to colourless.

Control: 1. The volume of appropriate lemon juice used for each experiment. 4.00 cm? of appropriate lemon juice is poured into the 100 cm? mensurating cylinder for each three experiment.

2. The volume of D.C.P.I.P used for every test. By utilizing a syringe 1 cm? of D.C.P.I.P is being assorted with distilled H2O and lemon juice.

3. The volume of glacial acetic acid used to blend with distilled H2O and lemon juice. For each experiment, merely 10.0 cm? of glacial acetic acid is being poured in the solution.

## Apparatus:

## Apparatus

## Measure

10 cm? mensurating cylinder

1

100 cm? mensurating cylinder

1

Burette

1

Conic flasks

1

Retort base

1

Syringe

1

50 cm? beaker

1

Table 1: The list of setup

## Material:

## Material

## Measure

Glacial acetic acid

Some

Distilled H2O

Some

D.C.P.I.P

Some

Lemon juice

4.0 cm? for each sort of juice

Table 2: The list of stuff

## Method:

Refer to the fond regard.

## DATA PROCESSING AND PRESENTATION

## QUANTITATIVE DATA:

Number

Juice sample ( lemon )

Tests

The volume of solution* usage to cut down the blue of D.C.P.I.P to colourless, V, cm? , ( ±0.05 cm? )

Initial

Concluding

1

Fresh

1

2

3

4

5

3.90

0.00

1.00

0.00

11.00

9.50

8.00

6.20

6.00

16.50

2

Boiled for 10 min

1

2

3

4

5

6.10

0.00

9.90

0.00

1.00

12.80

8.90

17.50

7.80

10.00

3

Boiled for 1 hr

1

2

3

4

5

0.00

0.00

8.50

0.00

7.00

9.50

13.70

16.80

9.10

15.30

Table 3: The volume of solution* used to cut down the bluish coloring material of D.C.P.I.P to colourless, V, cm? utilizing different sort of lemon juice.

Uncertainty for mensurating cylinder = ( ± 0.1 cm? )

Volume of glacial acetic acid = ( 10.0 ± 0.1 ) cm?

Volume of appropriate lemon juice = ( 4.0 ± 0.1 ) cm?

Volume of D.C.P.I.P = ( 1.0 ± 0.1 ) cm?

Volume of solution* = ( 100.0 ± 0.5 ) cm?

## QUALITATIVE DATA:

Observation:

The coloring material of D.C.P.I.P alterations from blue to colourless when the lemon juice is being titrated into it.

The juice is xanthous in coloring material and go lighter when it is diluted with acid and H2O.

## DATA Processing:

## The volume of solution*

The volume of solution* is calculated by utilizing the measure below ;

( Concluding volume – initial volume ) cm3

For illustration, the volume of solution for the first test which tested upon the fresh lemon juice:

9.50cm? – 3.90 cm? = ( 5.60 ± 0.10 ) cm?

The volume of solution for other tests for each appropriate lemon juice is calculated utilizing the same method as above.

## The mean volume of solution*

The mean volume of solution is counted by spliting the volume ( calculated in ( a ) ) with 5 tests. The expression is illustrated below:

Volume for ( test 1 + test 2 + test 3 + test 4 + test 5 ) cm?

5

The fresh lemon juice is taken as the illustration for this expression.

= ( 5.60 + 8.00 + 5.20 + 6.00 + 5.50 ) cm?

5

= 30.30 cm?

5

= ( 6.06±0.10 ) cm?

The computation for the other two appropriate lemon juices will be utilizing the same method as shown in ( 2 ) .

## The concentration of ascorbic acid in each lemon juice

The computation to find the concentration of ascorbic acid in each juice is shown below ;

The mass of ascorbic acerb equivalent to 1 cm3 D.C.P.I.P = 0.05 milligram

Now n cm3 of the juice solution* = 1 cm3 D.C.P.I.P

So, n cm3 of the solution* = 0.05 milligram ascorbic acid

Therefore, 1 cm3 of the solution* = milligram ascorbic acid

Therefore, 1 cm3 of the original juice = milligram ascorbic acid

Therefore, concentration of ascorbic acid in original juice

= mg/100cm3

For illustration, the computation for finding the concentration of fresh lemon juice.

Average volume for solution* = 6.06 cm?

The mass of ascorbic acerb equivalent to 1 cm3 D.C.P.I.P = 0.05 milligram

Now 6.06 cm3 of the juice solution* = 1 cm3 D.C.P.I.P

So, 6.06 cm3 of the solution* = 0.05 milligram ascorbic acid

Therefore, 1 cm3 of the solution* = milligram ascorbic acid

Therefore, 1 cm3 of the original juice = milligram ascorbic acid

Therefore, concentration of ascorbic acid in original juice

= mg/100cm3

= 20.63 mg/100 cm?

The computation of concentration ascorbic acid for other appropriate lemon juice is counted utilizing the stairss in no ( 2 ) above.

## The computation of standard divergence

The computation of standard divergence for the concentration of ascorbic acid in each lemon juice is measured by utilizing the expression below.

? M = ?V1 + ?V2 + ?V3 + ?V4 + ?V5 x M

V1 V2 V3 V4 V5

?M = the uncertainness for the concentration of ascorbic acid in the lemon juice

M = the concentration of ascorbic acid in the lemon juice

?V1 = the uncertainness for the volume of D.C.P.I.P ( syringe )

V1 = the volume of D.C.P.I.P ( syringe )

?V2 = the uncertainness of the volume of glacial acetic acid ( 10cm? mensurating cylinder )

V2 = the volume of glacial acetic acid ( 10cm? mensurating cylinder )

?V3 = the uncertainness for the volume of appropriate lemon juice ( 10cm? mensurating cylinder )

V3 = the volume of appropriate lemon juice ( 10cm? mensurating cylinder )

?V4 = the uncertainness for the volume of solution* ( 100 cm? mensurating cylinder )

V4 = the volume of solution* ( 100 cm? mensurating cylinder )

?V5 = the uncertainness for the mean volume of solution in burette

V5 = the mean volume of solution in burette

An illustration for finding the standard divergence of the concentration of ascorbic acid in the lemon juice is shown below.

Fresh lemon juice,

? M = 0.1 + 0.1 + 0.1 + 0.5 + 0.10 x 20.63

1.0 10.0 4.0 100.0 6.06

= ± 3.23 mg/100 cm?

The computation for other standard divergence will be utilizing the same expression as above.

## The tabular arraies for informations processing and graph

Number

The cookery clip for the sample of juice ( lemon )

The mean volume of solution* usage to cut down the blue of D.C.P.I.P to colourless, V, cm? , ( ±0.10 cm? )

The concentration of ascorbic acid in each lemon juice, M, mg/100 cm?

The standard divergence for the concentration of ascorbic acid in each lemon juice, M, mg/100 cm? ( ± )

1

0 min ( fresh )

6.06

20.63

3.23

2

10 min

8.00

15.63

2.38

3

1 hr

9.78

12.78

1.92

Table 4: The concentration of ascorbic acid in the lemon juice, M, mg/100 cm? for each sample.

## Discussion

D.C.P.I.P is used as an index for vitamin C. If more vitamin C or ascorbic acid is found in the nutrient, so the rate for the D.C.P.I.P to alter its bluish coloring material will go faster.

D.C.P.I.P ( blue ) + ascorbic acid D.C.P.I.P.H2 ( colourless )

The saloon graph shows the relationship between the cookery clip for the juice sample and the concentration of ascorbic acid in these lemon juice, M, mg/100 cm? .

Harmonizing to the saloon graph, the highest concentration of ascorbic acid is in the fresh lemon juice which is 20.63 mg/100 cm? . This shows that, a fresh uncooked fruits contain a batch of vitamin C which is besides known as the ascorbic acid. By detecting the saloon graph above, we can state that there is about 100 % of vitamin C contain in the fresh lemon juice or other fruits.

If the concentration of ascorbic acid contain in the lemon juice is higher, so less solution* is needed to undergo this titration. By mentioning to the Table 4, merely 6.06 cm? of solution* is required for altering the bluish coloring material of D.C.P.I.P to colourless.

15.63 mg/100 cm? of the concentration of ascorbic acid has been measured in the lemon juice boiled for about 10 proceedingss. This shows that even though the liquid is boiled for a short clip period, but it has affected the vitamin C in the juice rather much.

The poached lemon juice ( 1 hr ) has lowest concentration of ascorbic acid which is 12.78 mg/100 cm? and it is clearly shown by the saloon graph. From this observation, we can state that, when the lemon juice is being cooked, the sum of ascorbic acid is reduced because a batch of vitamin C has been destructing while boiling the juice.

Ascorbic acerb nowadays in about all fruits and vegetable that adult male chows. For illustration, Psidium littorale, citrous fruit fruits, Spinacia oleracea, Brassica oleracea italica and murphies. They are best devouring when they are still fresh. However, if people still want to cook them, do certain they set the fruits and vegetable on fire less than 10 proceedingss. This is of import in order to maintain the vitamin C concentration in the fruits or vegetable which is indispensable for our organic structure system.

## LIMITATION AND SUGGESTION

Restriction

Suggestion

The manner of agitating the D.C.P.I.P in the conelike flask. The D.C.P.I.P in some mixture turns to colourless faster than it should be. This has affected the mass of ascorbic acid used in the experiment.

Shake the conelike flask which contains the D.C.P.I.P easy. For each experiment, merely one individual is assigned to agitate the D.C.P.I.P as to synchronise the force incurred onto the solution. Thus the accurate volume of ascorbic acid can be obtained during the experiment.

The solution is non good mix. When the liquid is poured into the burette, some of the lemon juice assembles at the top of the setup. Therefore, when it is being titrated, the concentration of ascorbic acid is non to the full obtained.

Before seting the solution* into the burette, stir the distilled H2O, glacial acetic acid and lemon juice good by utilizing a glass rod. The procedure can be done in the 100 cm? mensurating cylinder.

The color alteration of D.C.P.I.P is rather hard to be seen. Student could sometimes misinterpret the exact clip when the alterations of coloring material occur. This may take to a fluctuation in the volume of solution* used during titration.

Placed a white tile under the conelike flasks as to do it easy to see the color alteration of the solution. This may assist in acquiring the accurate volume of solution used to titrate the D.C.P.I.P.

Parallax mistake may happen while reading the volume of solution* in the burette. This is more complicated particularly when the bubble accumulate at the surface of the solution* .

Make sure the oculus is parallel to the semilunar cartilage of the solution ( H2O ) . For both initial and concluding volume, see the reading below the bubble. By making so, an accurate volume may be achieve

## Decision

Therefore as the decision, when longer clip is spent to boil the lemon juice, so the concentration of vitamin C in that lemon juice will cut down. As the consequence, higher volume of solution* is needed to titrate with the D.C.P.I.P. Higher measure of solution* is besides used to discolor the bluish solution of D.C.P.I.P during the experiment. Therefore, the hypothesis is supported.

*solution = appropriate lemon juice + distilled H2O + glacial acetic acid