This experiment was planned to analyze how different temperatures can impact the loss of vitamin C in orange juice stored for a fixed period of clip. Equal volume of freshly squeezed orange juices with known ( initial ) vitamin C concentration were stored at different temperatures i.e. 10oC, 20 oC, 30 oC, 40 oC, 50 oC and 60 oC for a changeless continuance of 5 yearss. After the storage period, the vitamin C concentration for each temperature was measured by DCPIP titration and the difference relation to the initial concentration was calculated to cipher the sum of vitamin C reduced.
The consequence of this experiment showed that the sum of vitamin C lost additions with the addition in temperature and 10oC was the best temperature that gave the least decrease in vitamin C concentration. An analysis utilizing Pearson product-moment correlativity coefficient has revealed a strong positive linear relationship between the two variables with the deliberate R value exceeds the critical value at 5 % important degree therefore, back uping the experimental hypothesis.
Keywords: vitamin C, ascorbic acid, DCPIP ( dichlorophenolindophenol )
Research and Rationale:
Vitamin C is a singular compound derived from one of the ascorbic enantiomorphs, L-ascorbate. It is a H2O soluble vitamin that can non be of course synthesized in human body.1 Therefore, it is critical to hold our diet balanced with equal sum of it every twenty-four hours. There are two of import functions played by vitamin C ; antioxidant and collagen formation.2 These two characteristics have placed vitamin C in a category of its ain as a future potency in furthering better wellness.
A old research sing relationship between vitamin C and human encephalon has shown that vitamin C could assist drugs to go through the blood encephalon barrier.6 This would enable encephalon diseases such as Parkinson to be efficaciously treated as unreal Dopastat can be delivered straight to the encephalon. At the same clip, the biggest challenge in bone marrow intervention i.e. acquiring adequate cells, could perchance be solved as a recent survey by Dunagqing Pei13 on vitamin C, has found that it can hike the production and pluripotency of root cells in human organic structure.
However, Vitamin C is besides known to be really vulnerable towards heat. The precursor of vitamin C, ascorbic acid, has molecular of C6H8O6. The propinquity of extremely negatively charged O atoms on the hydroxyl ( OH ) groups makes the H atoms to go easy detached from the construction. Meanwhile, the presence of heat causes the hydroxyl bond to interrupt the ascorbic acid is said to undergo “ devastation ” or oxidization by losing H atoms, organizing dehydroascorbic acid. Therefore, it is suggested that the rate of ascorbic acerb devastation is significantly greater at higher temperature. *
Diagram 1. The construction of Ascorbic Acid.7
Diagram 2. Oxidation of Ascorbic Acid.8
Most of the surveies on vitamin C debasement are chiefly based on the consequence of storage status and period, and really few were done on placing the debasement tendency within a specific scope of temperature.
Previous research3, on the consequence of storage methods and conditions on vitamin C keeping in human milk revealed that stop deading reduces the least sum of vitamin C as compared to other storage methods, followed by infrigidation which is better than cold H2O. Another survey at Ankara University4, has shown an opposite relationship between temperature and keeping rate of vitamin C in citrous fruit fruit dressed ores, while orange fruit was found to hold higher keeping ability than the others.
Therefore, this experiment was aimed to happen a specific tendency sing the consequence of temperature on the loss of vitamin C. Citrus fruits ( orange ) were used in this experiment due to appreciable sum of vitamin C that they have, therefore, increasing the dependability of the consequences. The consequences from this survey can be used to exemplify how certain temperatures can do drastic alteration in vitamin C hence, increasing the consciousness on appreciating the attempt of continuing vitamin C content in nutrient for optimal wellness benefit. For case, in agricultural tropical parts that grow citrous fruit fruits, it becomes really critical to continue the fruits at low temperature if possible due to higher opportunity of vitamin C devastation than other parts.
The higher the temperature, the higher the debasement of vitamin C in newly squeezed orange juice.
There is no important relationship between the different temperature and the debasement of vitamin C in newly squeezed orange juice.
1 ) Choosing the best citrous fruit fruits:
Volume of Juice Titrated / milliliter
4.2 Five types of citrous fruit fruits were indiscriminately chosen, namel: lemon, calcium hydroxide, Citrus paradisi, Clementine and orange. The fresh juice of each fruit was obtained through cutting and squashing. The vitamin C content for each juice was determined by titration against 1 milliliter of 1 % DCPIP. The titration was repeated two times to acquire an mean volume of the juice needed to bleach DCPIP. The consequence:
Table 1. Vitamin C content in some citrous fruit fruits
The least volume of orange was needed to bleach DCPIP, bespeaking that it has the highest vitamin C content. Therefore, orange fruit was chosen as it would give important response towards different temperatures.
3 ) Determining the best storage period:
Several orange fruits were squeezed to obtain fresh orange juice that would be plenty for its vitamin C content to be measured on day-to-day footing. First, the initial vitamin C content of the juice was measured and 4.8 milliliter was needed to bleach 1 milliliter of DCPIP solution. Equal volume of the staying juice was divided into two beakers and each was stored in an brooder of different temperatures ( 10 oC and 60 oC ) . Two typical temperatures were chosen to let easy comparing of the tendency in each temperature. The consequence:
Volume of Juice Titrated / milliliter
Table 2. Change in vitamin C content for juice stored in two temperatures for a hebdomad
The consequence shows no more alteration in volume of juice required after 5 yearss for 60 oC. Therefore, storage period of five yearss were chosen for the chief experiment.
Manipulated variable: Different temperatures ( oC )
( 6 brooders were set at different temperatures of
10 oC, 20 oC 0, 30 oC, 40 oC, 50 oC and 60 oC )
Reacting variable: Sum of vitamin C lost
( By DCPIP titration, the difference between initial and concluding vitamin C concentration in each juice was
calculated to find the concentration of vitamin C reduced )
Fixed variables: Storage period, volume and concentration of DCPIP, type of fruits
( The storage period was five yearss. 1ml of 0.1 % DCPIP
Used for each titration )
Beakers, knife, trial tubings, panpipes, Parafilm, aluminium paper, brooders, howitzer and stamp, mensurating cylinder.
Orange fruits, 1 % dichlorophenolinophenol ( DCPIP ) solution, distilled H2O, 500 milligram vitamin C tablet.
Real Experimental Procedures:
Standardizing Vitamin C Concentration:
1 ) A tablet of 500 milligrams vitamin C tablet was crushed into all right pulverizations utilizing a howitzer and a stamp.
2 ) The powdered signifier of vitamin C was so dissolved into 100 milliliter of distilled H2O in a beaker to organize 5 mg/ml of ascorbic solution.
3 ) 1 milliliter of 1 % DCPIP solution was measured and placed into a trial tubing by utilizing a syringe.
4 ) 1 milliliter of 5 mg/ml of ascorbic acerb solution was so taken utilizing a syringe and added bead by bead into the measured DCPIP solution until decolourised.
5 ) The volume of ascorbic acerb solution needed to bleach the DCPIP solution was recorded.
6 ) The titration procedure was repeater three times to acquire an mean volume.
The consequence of titration is as follows:
Volume of Juice Titrated / milliliter
Table 3. Volume of ascorbic acerb solution titrated
Hence, 2.5 milliliter of 5 mg/ml of ascorbic acerb solution was needed to bleach 1 milliliter of 1 % DCPIP solution
To happen a expression to cipher vitamin C concentration in orange juice,
Conc. of orange juice ( mg/ml ) Vol. of orange juice ( mg/ml )
5 mg/ml 2.5 milliliter
Since the volume needed to bleach is relative to vitamin C concentration. So.
Conc. of orange juice ( milliliter ) 2.5 milliliter
5 mg/ml Vol. of orange juice ( mg/ml )
Concentration of orange juice ( mg/ml ) = X 5 mg/ml
Vol. of orange juice ( milliliter )
Therefore, this computation would be used to cipher the vitamin C concentration.
Determining vitamin C loss:
10 orange fruits were cut and squeezed to obtain fresh juice.
1 milliliter of 1 % DCPIP solution was measured and placed into a trial tubing by utilizing a syringe.
1 ml syringe was filled with the orange juice and added bead by bead into the DCPIP solution until it decolourised. The volume of juice added was recorded.
The titration was repeated five times to acquire an mean volume and its vitamin C concentration was calculated utilizing the derived expression.
The juice was so divided into 6 equal volumes and each placed into 100 milliliter beaker.
The top of each beaker was sealed with Parafilm and its surface was wrapped with aluminium paper and labelled with different temperatures.
The beakers were placed in six brooders of different temperatures harmonizing to the label and left for five yearss.
After five yearss, the beakers were sealed off.
1 milliliter of 1 % DCPIP solution was measured and transferred into a trial tubing by utilizing a syringe.
The orange juice stored in 10 oC was taken by a syringe and added bead by bead into the DCPIP until it decolourised. The volume of juice added was recorded
The titration was titrated three times to acquire an mean volume and its vitamin C concentration was calculated utilizing the expression:
Concentration of orange juice ( mg/ml ) = X 5 mg/ml
Vol. of orange juice ( milliliter )
Stairss 8-10 were repeated but this clip utilizing the orange juices stored in oC, 30 oC, 40 oC, 50 oC and 60 oC.
The difference between the initial concentration and the concluding concentration of each juice was calculated to find the sum of vitamin C lost.
The procedure of cutting the orange fruits required the usage of knife, so it was done carefully to avoid any hurt. The fruits were so squeezed really gently to understate heat production. The juice was merely prepared right before the experiment was about to be carried out. DCPIP is a strong dye which is difficult to be removed so lab coat was worn. During the titration of juice against DCPIP, the trial tubing was non shaken smartly to avoid O from fade outing. The juice was discarded instantly after the experiment.
The initial vitamin C concentration:
Volume Needed to Decolourise DCPIP Solution ( milliliter )
Table 3. Average volume of fresh orange juice titrated
Therefore, 4.6 milliliter of the fresh orange juice needed to bleach DCPIP. So,
Initial vitamin C concentration = X 5 mg/ml
= 2.7174 a‰? 2.72 mg/ml
Hence, the vitamin C reduced:
= 2.72 – Ten
* ten is Vitamin C concentration left.
Vitamin C concentration lost in different temperatures:
( oC )
Volume Needed to Bleach
( milliliter )
( mg/ml )
Reduced ( mg/ml )
Table 5. Sum of vitamin C loss ( mg/ml ) with regard to different temperatures ( oC )
Based on the consequence from the tabular array, it is known that there is an obvious tendency and correlativity between the temperature and vitamin C loss. Therefore, Pearson product-moment correlativity coefficient ( PMCC ) was chosen to mensurate the strength of this relationship.
In this method, the value of correlativity coefficient, R demands to be calculated which ranges from -1 to 1. The inside informations of its values are as follow:
0 & lt ; r a‰¤ 1 = positive linear relationship
-1 a‰¤ R & lt ; 0 = negative linear relationship
a?‘x = 210
a?‘ x2= 9100
a?‘y = 6.61
a?‘ y2= 10.9659
a?‘ xy= 308.3
*S= Summation of ( a?‘ )
Sxx = a?‘x2 – ( a?‘x ) 2
= 9100 – ( 210 ) 2 = 1750
Syy = a?‘y2 – ( a?‘y ) 2
= 10.9659 – ( 6.61 ) 2 = 3.68388
Sxy = a?‘xy – ( a?‘x ) ( a?‘y )
= 308.3 – ( 210 ) ( 6.61 ) = 76.95
a?s ( Sxx X Syy )
R = = 0.9584 ( & gt ; 0.811 ( critical part ) for 5 % significance degree )
a?s ( 1750 X 3.68388 )
* Critical values for PMCC in appendix 1
Therefore, the value of correlativity coefficient, R, utilizing Pearson product-moment correlativity coefficient has shown a strong positive linear relationship between temperatures and loss of vitamin C. Hence, void hypothesis is rejected.
Table 4 shows the volume of the freshly-squeezed orange juice needed to bleach 1ml of 1 % DCPIP solution. The mean volume was used to cipher the concentration of vitamin C nowadays ab initio. Meanwhile, Table 5 shows the sum of vitamin C concentration reduced after being stored at different temperatures for five yearss. From the tabular array, there is an reverse relationship between the vitamin C concentration left and the sum of vitamin C lost. There is besides a immense difference in the sum of vitamin C left between the juice stored in 10 oC andt the one stored at 60 oC, which is 2.11 mg/ml. This represents 77.6 % of the original concentration of vitamin C. The deliberate statistical correlativity coefficient, R of 0.9584 is perfectly a strong index to back up this relationship.
Graph 1 illustrates the tendencies and correlativity between the two variables. From the graph, it can be concluded that by and large, the higher the temperature, the higher the sum of vitamin C lost. 10 oC is the best temperature that gave the least decrease in vitamin C degree with merely 0.12 mg/ml ( 4.4 % ) lessening after five yearss. Meanwhile, 60 oC caused maximal bead in concentration after five yearss with 2.23 mg/ml ( 82 % ) of vitamin C had lost. The largest spread in vitamin C loss occurred between 40 oC and 50 oC with 1 mg/ml ( 37 % ) of addition recorded.
Based on the graph, the sum of debasement at 20 oC and 30 oC opposed the general tendencies when 0.6 mg/ml vitamin C had lost at 10 oC which is greater than 0.56 mg/ml at 30 oC. However, the difference is so little which suggests that this anomalousness might be due to several grounds:
Higher rate of oxidization of ascorbic acid by O in the ambiance.
False end-point titration
Apart from that, the consequences obtained have besides shown that there is merely a small alteration in vitamin C concentration from 10 oC to 30 oC. However, drastic alteration in concentration started to happen after 40 oC. This suggests that orange fruits should be kept below 30 oC with better vitamin C keeping at lower temperature.
From the consequences of the experiment, the immense difference in vitamin C lost between 40 oC and 50oC could be explained by the presence of enzyme ascorbate oxidase in citrous fruit fruits. The map of this enzyme is still non to the full understood, but one best suggestion is that it might affect in commanding the oxidization procedure of ascorbic acid.12 Just like any other enzymes, when the optimal temperature is exceeded, the bonds keeping the ascorbate oxidase together get down to interrupt and it is said to be denatured. Therefore, the “ devastation ” of ascorbic acid takes topographic point without any control.
Measurement of vitamin C in this experiment was done by titrating the juice against dichlorophenolindophenol ( DCPIP ) . It is a strong oxidizing agent with typical bluish coloring material and decolourised when being reduced by vitamin C.15 Therefore, the devastation of vitamin C by heat agencies that more is needed to bleach DCPIP solution.
Oxidation of DCPIP by O in the ambiance is one of the restrictions of this experiment. Hence, the trial tubings were non shaken smartly during titration in order to understate this restriction as vigorous moves can increase the rate of O dissolution in a solution.
The other restriction could be the side decomposition of vitamin C due to the presence of visible radiation and air. Just like temperature, ultraviolet beam from incidence visible radiation causes the hydroxyl bond in ascorbic acid to interrupt, therefore become oxidized. To cut down this restriction, the beakers incorporating orange juice to be stored at different temperatures were neatly wrapped with aluminum paper which is a good reflector of visible radiation and heat. The surfaced of the beakers were besides sealed with Parafilm. This would forestall the entry of air and significantly cut down unneeded oxidization of vitamin C in the juice.
Several alterations can be made in the hereafter to better the truth and dependability of the consequences of this experiment. Iodine titration could be used as an option for DCPIP titration. Although this technique may necessitate the usage of more reagents, the consequence from the test experiment has shown that the terminal point of titration is much easier to be identified. Besides, orange juice could be obtained by intermixing the bare-assed orange fruits alternatively of squashing them. This ensures maximal sum of juice obtained from each fruit every bit good as forestalling devastation of vitamin C by heat. Finally, per centum of vitamin C degraded can be used as the response variable alternatively of concentration. This would let clearer illustration of the sum of vitamin C reduced for the readers and besides make the comparing procedure easier.
Based on the consequence of this experiment, it can be concluded that the higher the temperature, the greater the debasement of vitamin C in newly squeezed orange juice. The statistically calculated R value utilizing Pearson product-moment correlativity coefficient, 0.9584, is significantly higher than the critical value at 5 % significance degree therefore, supplying a strong grounds to back up the hypothesis.
The tabular array of significance values for PMCC
Degree of freedom = n-2
n = figure of informations braces
= 6-2 = 4
Significance degree for two-tailed trial ( % )
Several resorts were used in supplying me of import information in finishing this assignment. Sources 1 and 2 are books that are specially made about fruit direction and besides detailed information about vitamin C every bit good as obliging research on it. Both books were published after twelvemonth 2005, so the information available is largely up to day of the month.
Besides, I have besides accessed diaries available online. Sources 3 and 4 come from two good known web sites for nutrient and nutrition based diaries. The American Journal of Clinical Nutrition is a trustable web site with over 3100 members, printing up to day of the months research related to nutrition and homo.
Beginnings 7, 8 and 9 are chemical science based web sites, functioning tremendous information on the constructions and reaction of biological compounds. Chemwiki is a practical online based chemical science text edition, accessed by 1000000s of people seeking for chemical science cognition. Sources 10 and 11 are web sites entirely made for vitamin C. The Vitamin C Foundation, for case, is recognised by Internal Revenue Service, IRS in protecting huge information about vitamin C for public mention.
Beginning 12, Scientific American magazine is a popular scientific magazine established for about two centuries since 1845 with more than 3.5 million readers all over the universe. Therefore, there would be no uncertainty in dependability of the content in this magazine.
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