Chemistry Vitamin CEssay Preview: Chemistry Vitamin CReport this essaytamin C, ascorbic acid, is one of the most important vitamins found in citrus juices, including orange juice.Often projects find that orange juices made from frozen concentrated orange juice (FCOJ) have the highest vitamin C levels as compared to freshly squeezed or not-from-concentrate (NFC) juices. This is probably due to the fact that vitamin C degrades over time in fresh and NFC, but doesnt degrade as much in FCOJ due to it being frozen until reconstitution. If one is comparing a NFC product that has been stored for about 3 weeks versus a newly reconstituted FCOJ, the FCOJ would almost certainly have a higher vitamin C concentration. Also another thing to consider is if the FCOJ is reconstituted to the same strength as fresh or NFC. If one doesnt add enough water, then the vitamin C (and other compounds) would be more concentrated. Another consideration is that the vitamin C content changes through the harvest season and orange variety also plays a part. Since most FCOJ is blended to a larger extent than some NFCs, it is entirely possible that the NFC is produced from a variety/season that has a lower vitamin C content.
According to Nagy and Smoot, temperature and storage time affects the percent of vitamin C content of orange fruits and orange juice. Different varieties of oranges also have different levels of vitamin C. The mid-season variety, Pineapple Orange had the highest levels, followed by the main early-season variety, Hamlin Orange. The late-season Valencia Orange had the lowest vitamin C content. Additionally, it was found that the longer the Valencia Orange fruit stayed on the tree, the lower the vitamin C level. (Additional details on these orange varieties can be found from links in The Story of Florida Orange Juice – From the Grove to Your Glass.) Nagy and Smoot also found that in orange juice containers, vitamin C loss was due to oxidation by a residual air layer trapped within the container during processing. The loss was faster in the first 2 weeks and was more evident at higher storage temperatures. Therefore, orange juice must be kept cool to prevent vitamin C degradation as it is excellerated at high storage temperatures.
Nagy, in his Review of Vitamin C Contents of Citrus Fruit and Their Products, investigated what factors affected the vitamin C contents of citrus fruits. Vitamin C levels depend on six main factors:
Production factors and climate conditionsMaturity state and position on the treeType of citrus fruit (species and variety)Parameters used for processing into different productsType of containerHandling and storageProduction factors and climate conditions: High nitrogen fertilizer rates can lower vitamin C levels in citrus fruits. Proper potassium levels are also needed for good vitamin C levels. Additionally, climate, especially temperature — total available heat — affect vitamin C levels. Areas with cool nights produce citrus fruits with higher vitamin C levels. Hot tropical areas produce fruit with lower levels of vitamin C. Environmental conditions that increase the acidity of citrus fruits also increase vitamin C levels.
Maturity state and position on the tree: Vitamin C decreases during the ripening process. Immature fruit has the highest levels. The position on the tree also affects vitamin C levels. Since sunlight exposure enhances vitamin C levels, fruit positioned on the outside of the tree and on the south side have higher levels. Shaded inside fruit has the lowest.
Type of citrus fruit (species and variety): Early maturing varieties have higher levels that late maturing types. Early Hamlin and Navel fruits have more vitamin C than the late maturing Valencia. Tangerines tend to have lower levels of vitamin C than oranges due to its lower acid levels. Studies have found that the peel had the highest levels of vitamin C followed by the pulp then the juice. Only 26% of vitamin C of a citrus fruit can be found in the juice. The peel had 53% and the pulp and rag had 21%.
Parameters used for processing into different products: Frozen concentrated orange juice (FCOJ) and reconstituted FCOJ almost always have higher levels of vitamin C and is above the 100% US RDA values. This is most likely due to blending of early-season fruit with late season fruit. Canned single strength orange juice will have lower vitamin C levels due to heating during the canning process. NFC, Not -From-Concentrate, will vary due to the varieties being processed.
Type of container: In cans, which are not used very much today, it was found that enamel-lined cans had higher losses of vitamin C than plain tin cans. This was due to residual oxygen and vitamin C reacting with the tin. Glass packed orange juice provides poor retention of vitamin C, losing 10% after 4 months of storage. Older cardboard cartons lost up to 20%. (Today, most cartons have specially designed multi-layered oxygen and light barriers to protect both loss of vitamin C, flavor, and to enhance shelf-life.) FCOJ packed in foil-lined cardboard cans retained greater than 90% of their vitamin C after 12 months at -20oC.
Handling and storage: Oxygen is the most destructive ingredient in juice causing degradation of vitamin C. However, one of the major sugars found in orange juice, fructose, can also cause vitamin C breakdown. The higher the fructose content, the greater the loss of vitamin C. Conversely, higher acid levels of citric and malic acids stabilize vitamin C. Orange juice must be stored at proper cool temperatures with oxygen barriers for best retention of vitamin C levels. When fresh citrus is stored at 38oF for 12 weeks, there was no loss of vitamin C, but when stored at high temperatures, the loss was great.
“However, pasteurized orange juice is processed based on fruit availability at the time, and this could reflect the natural variability of vitamin C throughout the growing season for the fruit.” Pasteurized orange juice showed higher levels of vitamin C during the months of December through March, when vitamin C-rich Hamlin oranges were a major contributor to the orange juice market. Samples collected between May and July generally had lower values of vitamin C. “This probably reflected the use of larger amounts of Valencia oranges which have lower amounts of vitamin C of the three major Florida sweet oranges,” said Lee. the current study did not take into account any changes in vitamin
” the fruit was not consumed in the premarketing season.”Lee said he plans to continue to monitor the market and improve data collection. he also said he wants to see a broader level of investigation to study different fruit sources and different season to ensure consistency in the findings.‟Although the study was based on a sample of 11 healthy women, Lee believes that more attention is being paid to differences in vitamin C levels.‟Lee says that many of the reported differences between fruits and beverages come down to variation of fruits, while others reflect differences in the number of vitamin C molecules present in the fruit and the availability of orange juice.Lee says it is not possible to have accurate and representative data about the distribution of vitamin C in food components, whether they are consumed in different or different parts of an area, but Lee says that what is said, and what is not said can vary. he said he also will be updating his and other studies to reflect changes in variation or to allow a way for people to control for potential confounding factors.‡Lee notes that when an individual in such a high risk group of individuals has very low vitamin C levels, he or she tends to tend to consume other foods like fresh fruits, vegetables and whole grains. he said that as he does research in a different field of health, he hopes to expand the study to include new sources of vitamin C to get an unbiased picture and to get a clearer picture of the health impacts on those living in the same area as he/she.Lee has not given any comment on the conclusions of this research but said that the current results are consistent with other findings from other research and will be presented in coming months. He says that with the increased number of women using the vitamin C supplement today, it’s important to remember that most of these consumers use the same form of Vitamin C and that there are people outside the United States that are in some way similar either to or far from those who get vitamin C to supplement. He wants to encourage such consumer purchasing by limiting Vitamin C exposure to 5% or less.Lee was not able to provide any other detail about the findings of the current study and other research.In terms of other types of consumer items consumed, he feels that there are some things which could be taken out of the food supply which may or may not be beneficial as a result of other factors such as lack of sunlight or heat. He noted that this research and his approach to measuring the nutrient content of fruits and beverages could help in finding different benefits associated with using different fruits and beverages. however, he admits that he could easily see that it doesn’t reflect the