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. 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 ).
What is the consequence of cooking on the sum of vitamin C in nutrients?
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:
- 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.
- 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.
- 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.
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
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.
