Excerpt
Assignment Chemistry Food
I. Introduction
II. Sources
A.Vegetables
B. Fruits
C. Others
III. Chemical Structure
IV. Functions
A.Formation of Collagen
B. Antitoxin
C. Immune System
D. Others
V. Uses
A. Common Cold
B. Cancer
C. Cardiovascular Health
D. Others
VI. Deficiency and Toxicity
A. Scurvy
B. Side effects
VII. Requirements
VIII. Conclusion
IX. Bibliography III
I. Introduction
The discovery of ascorbic acid, better known as Vitamin C in1928 by the Hungarian Dr. Szent-Gyorgyi, a later Nobel Prize winner, was one of the biggest achievements in the biochemical area. It was without doubt a huge step for the improvement of the human health and well-being. With that discovery however a strong debate started around that important water-soluble vitamin. Another famous scientist, Dr. Linus Pauling proposed in 1970 that the daily intake of Vitamin C needs to be much higher than the officially recommended daily intake of 60mg per day. In his books, Pauling claims that mega doses of Vitamin C can treat the common cold efficiently. This arose a big controversy between scientists in the last years. But what is Vitamin C, what is its function in the human body, and can it really improve our health? Is it really a universal medicine or just another “usual” vitamin?
Certain is, that Vitamin C is a very important nutrient, which the human body has to obtain from outside sources; this is different to most animals, except guinea pigs, which can produce ascorbic acid in their livers from glucose. If we don’t get enough Vitamin C, it can cause severe damage to our bodies. Therefore we must ensure, that we obtain enough of it from our diet.
II. Sources
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Ascorbic acid is a water-soluble vitamin and is found mainly in fresh vegetables and fruits. Cooking can destroy Vitamin C, as it is one of the least stable vitamins.
A.Vegetables
Important vegetables, which contain Vitamin C are red & green peppers, spinach, Brussels sprouts, tomatoes, asparagus, kohlrabi and cabbage. Grains, seeds and beans don’t carry much of it.
B. Fruits
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The best known sources for Vitamin C are citrus fruits, like oranges, lemon, limes and grapefruits. Other fruits with high concentration of Vitamin C are rose hips, strawberry, black currants and papayas.
C. Others
Animal foods hardly contain Vitamin C. If only the liver parts have a high dose of it, as this is the organ, where animals produce their Vitamin C. In Pharmacies you can buy naturally produced Vitamin C supplements, usually made out of rose hips, peppers or citrus fruits. Synthesised ascorbic acid can be made out of corn syrup, which is high in dextrose, and sago palm. It can be produced in larger amounts than the natural products.
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Ascorbic acid (AA) is a highly polar compound; it is therefore soluble in aqueous conditions. AA is readily and reversibly oxidized to Dehydroascorbic acid. The Vitamin C, which occurs in most of our food, is the so-called L-Ascorbic Acid. The oxidation of L-AA to L-DehydroAA depends on several circumstances, e.g. Oxygen partial pressure, pH, temperature and the presence of heavy metal ions, like Cu2+ or Fe3+. The destruction of AA proceeds much faster in metal-catalysed reactions. The loss is therefore much higher. The whole procedure itself is very complex and won’t be discussed in detail.
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