All fruits used to make the fresh fruit juices in the experiment were purchased fresh so heat and length of time wouldnt have affected the vitamin C content too much. All the commercially sold juices were bought on the basis of popularity among teenagers in Japan. They were bought to represent the likely amount of vitamin C intake that Japanese teenagers would have during the winter when cooked vegetables would lose a lot of their vitamin C content. The fewer amounts of millilitres of juice it took to turn DCPIP from blue to clear, the larger the amount of vitamin C there was in the drink.
In procuring commercial fruit juices, it soon became apparent that all was not what it seemed. Some were heavily supplemented with vitamin C (e.g. the commercially sold lemon drink “C1000 Lemon” and other, while labeled as fruit juices, contained only 10% juice!) When the commercially sold lemon drink was first measured, the colour changed with a mere 0.1ml of lemon drink, or just four drops. So the experiment was repeated with a one in ten dilution of the lemon drink, this time giving a reading of 1.3ml.
Tinned mikan (tangerine) juice was used and juice prepared for other fruits, i.e. the tin juice was discarded and the mikan sections squeezed and filtered. The carton of grapefruit juice was labeled as containing 20% real fruit juice. This may be why the amount of ml of juice it took to turn the DCPIP from blue to clear was not established. Over 50ml’s of this grapefruit juice was titrated into the beaker containing DCPIP with little colour change observed. This was shown as more than 50ml on the bar chart, but in each case 75ml was run in without colour change observed.
After the DCPIP was too dilute to read the colour. The more than 50ml readings should be interpreted as effectively zero vitamin C content. The juice prepared with a fresh grapefruit showed that there was nearly as much vitamin C content as in the fresh lemon juice. Therefore, real grapefruit is high in vitamin C content.
The lemon drink tested was supposed to provide the daily intake of vitamin C. It only contained 10% real fruit juice. This means that vitamin C that was not naturally produced was inserted into the drink. This is obvious because when compared to the commercially sol lemon juice, the amount of fresh lemon juice needed to turn DCPIP from blue to clear was almost five times the mount of the commercially sold lemon juice. The commercially sold orange juice contained 100% real fruit juice. It is easy to tell that this juice was either heat treated or old, as it is 100% as real as the fresh orange juice made, but it took 0.6 more ml to turn the DCPIP from blue to clear.
The vitamin C content in the commercially sold orange juice was probably broken down a bit by being heat treated and being in storage and on a shelf for too long. It is because vitamin C is heat labile that the vitamin C broke down under these conditions. The carton of pomegranate ‘water’ contained 10% real juice. More than 50ml of the pomegranate ‘water’ were used to measure the change of DCPIP from blue to clear. On the bar chart it is shown as greater than 50ml though. However, this change was not observed even with that amount of the drink being used, therefore the effective vitamin C content was zero.
In the case of fresh pomegranate juice the change in colour was hard to observe/measure as the colour of the pomegranate juice and the pink stage of DCPIP was similar in colour. The difference in colour between the pomegranate juice with the DCPIP pink stage and the pomegranate juice by itself was observed better using a white tile beneath the beaker containing the DCPIP and a beaker of fresh pomegranate juice was place on an other white tile right beside it to make a clearer comparison. The apple drink (acerola) contained 10% real fruit juice. The acerola apple is different from the common eating apple used in the fresh fruit juice comparison. It is more closely related to the crab apple. It was found, after some more research, that acerola apples have a very high vitamin C content, more so than the common eating apple.
Although extra vitamin C may have been introduced into the drink [the package label was not helpful], the vitamin C content was still very high. It contained twenty times the mount of the fresh apple juice tested. Another popular Japanese apple drink called Ringo No Oishii Mizu (delicious apple water) was tested for vitamin C content. It contained 20% real fruit juice made of apples similar to those used for the fresh fruit juice tested.
With this apple drink it took 26.9ml before DCPIP turned clear. The mikan juice extracted from tinned mikan contained 100% real fruit juice. Tinned goods are heat treated, and are normally cooked as part of the canning process. Thins tend to have longer shelf and storage lives too, that would probably account for the decomposition of vitamin C that gave the relatively low reading in comparison to the fresh mikan juice. However, given the famed lability of vitamin C, the readings for canned mikan were surprisingly high and confound the accepted wisdom that “canned fruit contains no vitamin C”. The graph shows the different amount of each juice in millilitres needed to turn DCPIP from blue to clear.
i.e. a lower reading means more vitamin C. Showing it in graph from makes it easier to see the differences between the commercially sold drink in comparison the fresh fruit juice. The Amount of Each Drink in Millilitres Needed to Fulfill the Required Daily Allowance (RDA) of Vitamin C Commercially Sold Drinks Drink Amount of Juice in ml’s Needed to Turn 2ml’s of DCPIP from blue to clear Amount of Juice in ml’s Needed to Fulfill the RDA of Vitamin C Lemon (C1000) 0.13ml 8.4ml Orange 2.9ml 187.34ml Apple (acerola) 1.4ml 90.44ml Mikan 6.5ml 419.9ml Apple ( Oishii Mizu) 26.9ml 1737.74ml The above chart shows the amount of each commercially sold drink needed, in millilitres, to fulfill the required daily allowance (RDA) of vitamin C, which is 60mg of vitamin C.
This was figured out because the lemon drink contained 1000mg of vitamin C and was a bottle of 140ml. The following equation was then used to figure out how many millilitres of the lemon drink would provide a person with the RDA for vitamin C. The amount of mg’s of vitamin C in drink = The required daily allowance The amount of ml’s of drink x 1000 = 60 140 x In this equation x was 8.4. Then 8.4 was divided by 0.13 (the amount of lemon C1000 in ml’s needed to turn DCPIP from blue to clear). The number gotten by doing this was 64.6. This number was then multiplied by the amount of juice, in ml’s, needed to turn DCPIP from blue to clear to get the amount of juice in ml’s needed to fulfill the RDA of vitamin C.
This also applies to the next chart. For the lemon, orange, and apple (acerola) drink, the amounts needed to fulfill the RDA are relatively small. These are amount that could be easily consumed without much effort and disgust. For the mikan and apple drinks, the amounts needed to fulfill the RDA are sizeable in comparison to the lemon, orange, and acerola drinks. Pomegranate and grapefruit juice were not included in this chart since the amount of juice needed to turn DCPIP clear was more than the 75ml’s measured.
The amount of apple juice needed to fulfill the RDA is impractical for somebody. Drinking almost two litres of the apple juice in one day would be highly unlikely. Fresh Fruit Juices Drink Amount of Juice in ml’s Needed to Turn 2ml’s of DCPIP from blue to clear Amount of Juice in ml’s Needed to Fulfill the RDA of Vitamin C Lemon 2.0ml 129.2ml Orange 2.3ml 148.58ml Apple 23.1ml 1492.26ml Grapefruit 2.2ml 142.12ml Pomegranate 11.3ml 729.98ml For the lemon, orange, mikan, and grapefruit, the amounts needed to fulfill the RDA are relatively small. For the apple and pomegranate and apple juices, the amounts needed to fulfill the RDA are quite large. It would be impractical to drink that much apple juice just to get the RDA of vitamin C. The juice also tasted bad.
It would be fairly hard or expensive to get enough pomegranate juice to fulfill the RDA of vitamin C. However, it is also impractical to have about 130 millilitres of fresh lemon juice as it is very sour and not that tasty. Evaluation From the two types of drinks (commercially sold drinks and fresh fruit juices), fresh fruit juices tended to contain more vitamin C than the commercially sold juices of the same fruit. The commercially sold juices that had a larger vitamin c content than its equivalent fresh fruit juice were the lemon juice and the first apple juice tested. The lemon juice contained a lot more vitamin C because it was a vitamin C supplement drink for those in the winter with colds that don’t want to drink the hot cough drinks.
However, no other commercially sold lemon drink, that wasn’t a vitamin C supplement drink, was found. The first apple drink tested for vitamin C had extra vitamin C added and the type of apple used in the drink had a higher amount of vitamin C than the normal apple, which was used for the fresh fruit juice. Not all commercially sold drinks had a lower vitamin c content than their equivalent fresh fruit juice. This was especially not expected for the first apple juice tested.
Therefore, the hypothesis: since vitamin C is labile (susceptible to change and unstable), the commercially sold juices, which have most likely been heat treated and stored in various conditions for various periods of time, should have lower vitamin c content than fresh fruit juices, was not fully supported. This was due to the fact that assumptions were made on the vitamin C content of apples. It was thought that all apples would have toughly the same vitamin C content, as a result the expected measurements were not as expected. However, this was somewhat remedied by testing a different popular apple drink. The results from this test proved to be like those expected that were stated in the hypothesis.
If the experiment were to be repeated, the most likely change would be to get a wider variation of commercially sold drinks of the same fruit and, if possible, fresher fruit. Testing for the vitamin C content in, for example, three different commercially sold apple drinks may have given a more accurate picture of the vitamin C content in commercially sold apple drinks. The amount of vitamin C broken down in the canning or packaging process, along with the shelf life, may have also become more apparent. To get more accurate results, the experiment should have been done several times. With all t he results collected an average should have been calculated to give a more concise amount of vitamin C in the drinks tested, but time was limited. Another thing that would be good to do if the experiment were repeated would be to test how much pure vitamin C (ascorbic acid) it takes to turn DCPIP from blue to clear.
This was not achieved because there was no ascorbic acid powder available. Had it been available, it would have been used as a control. As a result, the amount of each juice in millilitres to meet the recommended daily allowance of vitamin C was figured out which served a purpose almost as good as the control method. In some cases it is conceivable that the volume of fruit or commercially sold drinks needed to meet the RDA would not be practicable. In short, it took from 50 – 500 millilitres less of fresh fruit juice than commercially sold drink to fulfill the RDA of vitamin C. This is for all fruits except the lemon and acerola commercially sold drinks as they had vitamin C added.
The results that were accumulated through this experiment were nearly all backed up by the hypothesis, with the exception of the lemon drink comparison for reasons stated earlier on in the paper. The conclusion was made, in answer to the research question: are commercially sold and popularly consumed juices (in Japan) a good substitute for fresh fruits in terms of dietary vitamin C? That commercially sold and popularly consumed juices (in Japan) are not a good substitute for fresh fruits (in the form of juices for the purpose of this experiment). This is because the vitamin C content for all, except the lemon juice and the first apple (acerola) juice tested, was higher in the fresh fruits than it was in the commercially sold drinks. So, it would benefit the majority of teenagers who buy the commercially sold drinks (thinking they contain more vitamin C among other vitamins and minerals) to drink fresh fruit juices if they want the proper amount of vitamin C.
Bibliography Endnotes 1) “Vitamin C Content of a Lemon ” The Chemicals of Life p.47 2) Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.11 3) Pitt, George “The Dark Side of Vitamins” Biological Science Review May, 1994, p.38 4) Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.12 5) http://www.cforyourself.com 6) http://www.cforyourself.com ; Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.12 7) http://www.cforyourself.com 8) “Vitamin C Content of a Lemon” The Chemicals of Life p.47 9) http://www.cforyourself.com Endnotes 1) “Vitamin C Content of a Lemon ” The Chemicals of Life p.47 2) Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.11 3) Pitt, George “The Dark Side of Vitamins” Biological Science Review May, 1994, p.38 4) Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.12 5) http://www.cforyourself.com 6) http://www.cforyourself.com ; Bates, Chris “Vitamin C, The Chameleon of the Vitamins” Biological Science Review November, 1991, p.12 7) http://www.cforyourself.com 8) “Vitamin C Content of a Lemon” The Chemicals of Life p.47 9) http://www.cforyourself.com.
