Vitamin C Practical Experiment Hypothesis; Based on knowledge already at hand, My hypothesis will be that freshly squeezed juice willcontain more vitamin C compared to juices that are from concentrate and that juice from lemons will contain more vitamin C due to their acidity. Vitamin C content in Juices No of drops of juice need to decolourise the DCPIP solution 7 6 5 4 3 2 1 0 Orange Cherry Tropical Lychee Mango Vitamin C 1% Types of juices Variables; Variables such as temperature could affect the results that are collected, as much as can be done to control the temperature to make the results accurate will be done, holding samples with hands can increase the temperature slightly so they will be handled by the lip of the vial and placed into a rack. When testing samples multiple times I will ensure that the equipment cleaned and dried or if possible new as the pH of water might affect the reaction of DCPIP and ascorbic acid, water can also affect the results depending on whether it is ‘hard water’ or ‘soft water’, hard water contains more mineral and more chlorine is present. Measuring will be as close to as possible accurate, this will include re-measuring samples. I will be measuring the amount of juice sample solution it takes to decolourise 1cm of DCPIP, first I will use a controlled sample of 1% vitamin C to decolourise the DCPIP, and with this I can compare results from the other juice samples. The measurements will be taken with a probably a greater accuracy then using a pipette. they are also smaller then Pyrex beakers which would spread the solution over a large surface where as a test tube would make it easier to establish decolourisation. A glass rod would allow a fair mixing of the solution but the effects on the results are unknown. which is a dye used to monitor light reaction in photosynthesis Apparatus & Chemicals. Pipette Fruit Juice Samples DCPIP 1% Solution Test tubes Test tube rack Burette (Possibly) Glass Rod (Possibly) I have decided to use test tubes because they provide a clear sight into the experiment at hand.2ml when measuring solutions. A burette would allow an accurate measure of how much solution has been added into the DCPIP. and this will be repeated on till decolourisation.6-dichlorophenolindophenol. . Vitamin C (Ascorbic Acid) has a pH of under 4-5 when diluted with water DCPIP. each time 1ml is released it will be shaken to allow a fair mix of solution. it is a suitable and vital piece of apparatus however there might be a probably with used pipettes as they can have dents from previous experiments and would only be accurate to around 0.pipette and released into the DCPIP 1ml at a time. Safety. 2. Pipettes are a fast way to measure the solution with a limited amount of time.0ml-0. Sanitise experimental area after. It shows the amount of juice required to decolourise the DCPIP.Take care of glassware. I will measure 1% DCPIP 1cm(3) from a beaker to a pipette. It was input into the table below.. Outliers will be excluded to keep the test accurate. The time allocated during this experiment is 1/2 hour. Do not drink juice samples as dangerous chemicals may be present after experimentation. with another pipette I will add the 1% vitamin C solution which is the control of the experiment 1cm(3) at a time to a test tube. The next juice two sample will be tested with the same amount of DCPIP. each time 1cm(3) is added. Wear eye protection at all times. I will repeat this on till the DCPIP solution is decolourised. The samples will be kept in a test tube rack to compare different colours. Accuracy could be improved but due to this some apparatus and time will be put aside in order to complete the experiment There are some ethical issues with testing these chemicals and releasing them into the sewer as they are not helpful to the environment due to their pH. To get a fair and accurate result I will repeat this 3 times and then average the results. Results. 3 tests were conducted and from that you can then work out the . I will gently stir the test tube to make sure then the reaction takes place. Pre-Experiment Method. The method I will be conducting is simple. T1+T2+T3 3 Once all of the data was collected. care will be taken so that any DCPIP and Vitamin C is not wasted and only what is needed is used. Care when handling juice samples or chemicals as they may stain. first placed into a test tube via pipette then another unused Pipette will extract the juice sample and will be added into the DCPIP 1ml at a time then stirred gently and this will continue on till the DCPIP is decolourised. 5ml 14ml 15ml 18ml 15. From this we can see that for pure orange juice and Vitamin C samples that there is a steady rise from test 1 to test 3. This line graph shows the plot of the tests carried out.3ml to decolourise the DCPIP which was 1. this could be due to a number of factors that I will include in my limitations. The results also prove my hypothesis is right that lemons contain more Vitamin C.13g Vitamin C the Jiff. This graph also shows standard deviation. 1% Solution did. . Solution took 7.3ml 0. to get the average. However the Jiff tests shows to be accurate and consistent from test 1 to test 3. The Vitamin C.8ml more than Jiff. There is a 4ml difference from test 1 to test 3 in the pure orange juice tests.average with a formula result from all 3 of the trials. Due to their acidity which is the sign of ascorbic acid (Vitamin C) and their low pH levels.5ml 5ml 6ml 5.06g Pure Orange to turn the Juice DCPIP 5. Of Juice Required to Decolourise 1cm(3) of 1% DCPIP Test 1 Test 2 Test 3 6ml 7ml 9ml Average Vitamin C. These results prove my hypothesis in that freshly squeezed fruit will contain more vitamin C. Vol. There is a 2ml difference from test 1 to test 2 in the Vitamin C 1% Solution Test.5ml 0.18g Jiff decolourised compared to the 15.6ml 0. The equation for the standard deviation used is. This suggests to me that Jiff contains less water than the Vitamin C. with an Solution average of 5. the average can be used to conclude a fair These results show that the juice sample that contains the most Vitamin C was 7. from the bars we can see the average of the test. I then calculated the Content of Vitamin C in each of the samples by Dividing them by the 1ml of 1% DCPIP Solution which gave the sum then converted to grams. Content With the average. it measures the spread of data from the mean. this is because it will not have been watered down by manufacturers for a higher quantity. The results conclude that the deviation is a Low standard deviation because the valves are not spread out so much.6ml of pure orange Juice. so these juice samples do quite well in the RDA perspective The graph shows that on all samples tested.05g more than the 1% vitamin C solution. From the results we can see that the Jiff has the highest amount of Vitamin C.5 G PER DAY From this we can see that Jiff reaches two times the amount of RDA in males.This pie chart shows the content of vitamin C. However the DCPIP was to a degree harder to measure due to the darkness of the . Post-Experiment Method. It has 3 times more than the Pure Orange Juice Sample. The pure orange juice reaches 66. Using the average of the volume of solution required to turn DCPIP into.0 G PER DAY RECOMMENDED DIETARY ALLOWANCE (ADULT FEMALE) 7. Present.6% of the RDA. Limitations and Variables. As planned the measurements of the juice solutions were accurately measured and did not obscure sight in the pipette. RECOMMENDED DIETARY ALLOWANCE (ADULT MALE) 9. it also contains 0. This RDA does include food intake. the vitamin C (ascorbic acid) content of 7 different types of fruit juices purchased from a supermarket. the solution did decolourise the solution but it turned to a yellow colour which was the original of the juice sample. gains an oxygen molecule. however all the of solutions would have had some water in them so this shouldn’t affect the results in a significant way. the result was that they did turn brown and that was expected to be the end of the trial. I will analyse by titration. I ended up having to clean them with tap water. Another Improvement is to be more careful with the juice samples and to keep them contained so that they are not affected by the elements. Post-Experiment Method. and enough so that other factors like water don’t come into play. In this investigation. One improvement that could be made to the experiment is the equipment. it was unknown that the 1% Vitamin C solution Control would turn into a brown colour when decolourised. The Pure Orange Juice also produced different than expected appearance. the pH of the water could affect the experiments outcome. having a larger choice to use from. Although this happened I still recorded the results and then continue to see if any difference would appear but after 5 minutes of no change they were placed into a test tube rack to be observed later on and compared with the other trials. as Vitamin C is a reducing agent it adds electrons therefore its used in this experiment because it will change colour. Oxidation is the opposite. We also do not know if Vitamin C is lost during ageing or through heat treatment which often products go through to ensure that it’s free from harmful bacteria. As this was the first time carrying out an experiment like this. One problem that I was faced with was the limited amount of apparatus. Other problem in the experiment that I later picked up on from observation was that the DCPIP and Juice solutions’ were left open meaning that oxidation could affect the results which is a loss of electrons and a gain in hydrogen.e.solution. Limitations and Variables-Continued. The experiment took slightly longer due to this as I had to wait for the solution to settle into the solution. One modification that could used is that now we know that after a certain colour in the process of decolourisation we know that the trial is finished therefore saving us time for something else. The amount of juices used to turn the DCPIP colourless will be recorded and the vitamin C content will be determined by measuring the . loses a hydrogen atom or loses electrons. this will cause the DCPIP to turn blue again. Reduction is where a molecule losses an oxygen molecule. more results would have given better accuracy in results and given me the chance to spot outliers in the experiment. at the presence of vitamin C. which will be reduced to a colourless form from dark blue. it covered the pipette in a dark blue colour and was hard to tell where and how much solution was being measured. they were dried but to a certain extent. I will test for the presence of vitamin C using an organic indicator solution called DCPIP (dichlorophenol indophenol). The limitation of this experiment is that it was only repeated three times due to the amount of time available. gains a hydrogen atom or gains electrons. i. but too much oxidation can be damaging to tissues and organs. into which the DCPIP and the juice is added. characteristics of scurvy. 3. etc. to measure out the DCPIP. 2. Method The experiment was performed at room temperature. List of equipment Volumetric flask to measure out the correct volume of DCPIP. Vitamin C prevents too much oxidation from occurring. bone.amount of drops of a known vitamin C concentration solution. Electronic balance to weight the correct amount of DCPIP. There are 4 ways in which vitamin C considerably benefits the body: 1. Oxidation of haemoglobin in the blood is necessary to survive. Vitamin C Vitamin C plays a vital part in the correct functioning of the living body (most animals synthesise their own vitamin C. This is the principal component of tendons. the body will be very susceptible to disease. we don t). Collagen. ligaments. 2ml syringe. fright or fight. 1 to containing the juice you wish to test and 1 for the DCPIP solution. Beaker. and cartilage. Immune system. Without vitamin C. This is for flight. . to measure out the quantity of juice added to the DCPIP. to hold the test tubes. loosening of gums and teeth. teeth. used to turn the DCPIP colourless. Vitamin C is involved in the production of white blood cells. blood vessel fragility. Test tube rack. 4. in addition to being the ground substance between cells. Vitamin C has also been linked in the prevention of heart disease and cancer. which are the main defence against disease. Inadequate vitamin C levels will lead to weakening of these areas leading to skin lesions. When the body is exposed to stress. Homeostasis. skin. 10 test tubes. the adrenal grand uses vitamin C to produce adrenaline in response to the stress by which blood will be moved to the muscles from the digestive system. 1ml syringe. Antioxidant. By doing this. by the amount of fruit juice needed to reduce the DCPIP. This is then multiplied by 0. The amount of 0. This procedure was repeated 10 times to provide an adequate level of accuracy to the experiment.05% vitamin C solution needed to reduce the DCPIP is recorded. The level was read from the bottom of the meniscus. Any difficulties or anomalies were also recorded.The juices used were: Orange juice Grapefruit juice Lemon juice Pineapple juice Mixed fruit juice Cranberry and raspberry juice Apple juice The first task was to measure out 1% DCPIP solution in the volumetric flask and to make sure it is completely mixed (distilled water is used so not to effect the accuracy of the experiment and a squeeze bottle can be used to top up the measurement for further accuracy). Calculation example: Volume of 0.55ml . 2ml of DCPIP are then put into each test tube using the 2ml syringe.05% vitamin C solution and is added drop by drop to each tube individually until the DCPIP has been reduced and the blue colour has disappeared. the vitamin C content of the fruit juices can be determined. The DCPIP can then be put in to a beaker to ease the filling of the syringes (DCPIP must not be left overnight to avoid oxidation which may affect the results).05% vitamin C solution is to determine the vitamin C concentration in the fruit juices by dividing the amount of 0.39ml Volume of orange juice needed to reduce DCPIP = 1.05 (the known concentration of the first solution). The relevance of testing the 0.05% vitamin C solution needed to reduce DCPIP = 0.05% vitamin C solution needed to reduce the DCPIP. The 1ml syringe is then filled with the 0. The test was then performed on the fruit juices of unknown vitamin C content. Juice with the most vitamin C: 52% orange juice 34% lemon juice 10% mixed fruit juice 2% cranberry and raspberry juice 2% grapefruit juice (0% for the rest) Juices with the least vitamin C: 32% apple juice . and a cross in the box beside the juice with the lowest vitamin C content.55 = 0.05% vit.05 1. C solution X 0.Vitamin C content of orange juice = volume of 0.05% Volume of orange juice = 0.39 X 0.013% Questionnaire Put a tick in the box beside the juice that you think has the highest vitamin C content. Orange juice Apple juice Lemon juice Pineapple juice Grapefruit juice mixed fruit juice Cranberry and raspberry juice Questionnaire The questionnaire was given to a sample of 50 people to get an idea on general thoughts on fruit juices vitamin C content. people believe the citrus fruits contain the most vitamin C. . Graph showing questionnaire results Juices with the most vitamin C content Juice a = orange juice Juice b = lemon juice Juice c = mixed fruit juice Juice d = cranberry and raspberry juice Juice e = grapefruit juice Juices with the least vitamin C content Juice a = apple juice Juice b = cranberry and raspberry juice Juice c = pineapple juice Juice d = mixed fruit juice Juice e = lemon juice Students T-test 1 Calculating the significant difference between the means of orange juice and pineapple juice.28% cranberry and raspberry 24% pineapple juice 10% mixed fruit juice 6% lemon juice (0% for the rest) Generally. To see if there is more or less than 95% confidence that the difference between the means has not occurred by chance alone. 00753 N Sx2 + Sy2 = 0. Students T-test 2 Calculating the significant difference between the means of orange juice and grapefruit juice.0750 Sx2 = 0.075295 Sy2 = 0. there is 99. In fact. Orange juice mean = 1.08996 T = 54.005625 Sx2 = 0.88 Standard deviation of orange juice = Sx =0.2744 Sy2 = 0.55 Pineapple juice mean = 6.43 Difference between them = 4.0080925 NN Standard error = 0.247 There is 95% confidence that the difference has not occurred by chance alone.93 Difference between them = 0.62 .Orange juice mean = 1.55 Grapefruit juice mean = 0.0005625 N Standard deviation of pineapple juice = Sy = 0. To see if there is more or less than 95% confidence that the difference between the means has not occurred by chance alone.9% confidence that the difference has not occurred by chance. the larger the deviation.0432 Sy2 = 0.9% confidence that the difference has not occurred by chance. Eventually. The standard deviation was calculated for the results obtained.Standard deviation of orange juice = Sx =0.653 There is 95% confidence that the difference has not occurred by chance alone.0750 Sx2 = 0. This greatly affected the results. there was a problem because one of the volumetric flasks had been filled with an incorrect amount of DCPIP. In fact. This had a significantly higher standard deviation because the apparatus was not accurate enough to measure .125ml of DCPIP was used in order for the complete reduction of the DCPIP. I found that after adding 15ml of juice to 2ml of 1% DCPIP. 0.0018662 Sy2 = 0. Analysis During the experiment. there was no change. When the apple juice was tested. the problem was swiftly rectified and the experiments were tested again with the correct DCPIP volume.005625 Sx2 = 0. The results found had relatively small standard deviations except for the apple juice.0001866 N Sx2 + Sy2 = 0. there is 99.2737 T = 22. The larger the spread.0005625 N Standard deviation of grapefruit juice = Sy = 0. This measures the spread of the individual measurements about the mean. Fortunately. This alteration decreased the accuracy of the results because very small volumes of DCPIP had to be measured out.00749 NN Standard error = 0. but still there was no change. This problem could have been avoided with more care and attention put into the measuring of the DCPIP. 1ml was tested. Use freshly squeezed juices so not to contain preservatives. But. The modern diet may lack vitamin C because most produce is preserved. This means that the results did not show how much vitamin C is in those two juices. This is probably from variations in procedure and the juices used. Blackcurrant juice was going to be tested because it is a well-known. In MEDCs (more economically developed countries). The levels of confidence found were 99. with a high vitamin C content.9% that difference between the two means were not by chance alone. However. The lemon juice found to have low vitamin C content. Also. but different brands contain different amounts of vitamin C so it has not proved a great deal. the vitamin C content may slightly under the correct amount because of preservation techniques (explained earlier). More repetitions could have been made with less amounts of DCPIP to reduce the spread and increase the accuracy. Vitamin C is added to some juice as an antioxidant to prevent the deterioration of the substance. The amount of vitamin C in different diets can vary tremendously. Nutrition and Health). in LEDCs (less economically developed countries). This means that the cranberry and raspberry juice and the mixed fruit juice did not have sufficient vitamin C in it originally. The reason why this test was not performed on this juice was because of its colour. but it may not prevent the breakdown of the vitamin C. had added vitamin C. but the ability to import fruits with high vitamin C content. This preservation may have affected the results but damaging the vitamin C in the juice. it contained preservatives (e. and food supplements (vitamin tablets) make up for that lack. so more had to be added. Their method in measuring the vitamin C content of juices could be very much different and so differences between the two experiments can occur. It would have been extremely difficult to accurately measure when all the DCPIP had been reduced to its colourless form because of blackcurrants deep colour. I found from the data that I collected that my vitamin C reading were a great deal higher than the data shown in the table (Food Science. non-citrus fruit drink. E220 V E227) to prevent the growth of any bacteria and to be able to last a long time without decay. but how much is in the cartons. adding preservatives may prevent the decay of the juice.g. The carton did not state how much vitamin C was added so it was not possible to allow for the addition. A more extensive investigation has to be carried out in order to get a better idea of the general trends in vitamin C content in fruit juices. . Conclusion This experiment has shown the vitamin C content of a small variety of juices. Ways in which to improve: Do more repetitions on different makes of juice in order to get a broader set of results.such low levels of vitamin C. The mixed fruit juice and cranberry and raspberry juice (the two highest results). where importation of fruit and food supplements are scarce. people do not understand the necessity of vitamin C (4 factors explained earlier) and the consequences of its deficiency (scurvy). but its deficiency could be reduced if people learned about its importance in the correct functioning of the human body.there is a high deficiency of vitamin C. This will reduce the levels of vitamin C in the body eventually resulting in scurvy. for a great deal of people. . e. Luckily. DCPIP (dichlorophenol-indophenol) is a blue dye which is decolourized by ascorbic acid on account of its reducing properties. Generally. The average person with a well balanced diet will be in the necessary requirement of vitamin C V between 75-100mg per day. However. a person with an unbalanced diet. due to its chemical structure. DCPIP is a redox dye usually used as a monitor of the light reactions in photosynthesis as it is an electron acceptor that is blue when oxidized and colourless when reduced. 30mg of vitamin C per day. a lot of food contains vitamin C.g. The dye changes colour when it is reduced. may be under this level.