Ascorbic Acid Determination

A redox titration, involving an Iodometric method, has been used to do the analysis. L-Ascorbic acid was first isolated as a pure substance by Albert Agent-Gyorgi and Charles King 1928, an anti-oxidant and free radical scavenger, is found ubiquitously in fruit and vegetables such as citrus fruits (oranges, lemons, limes, tangerines, etc. ), melons, tomatoes, peppers, broccoli, green leafy vegetables such as spinach, potatoes, and turnips, its quantitative determination is especially important in the production of wine, beer, milk, soft drinks, and fruit juices, where it can be a quality indicator. Given the essential role played in the human diet and necessary to growth and repair of tissues in all parts of the human body. It is necessary to form collagen important skin proteins, scar tissue, tendons, ligaments, and blood vessels. vitamin C is essential for the healing of wounds, and for the repair and maintenance of cartilage, bones, and teeth. Since vitamin C is easily oxidized, storage, and cooking in air leads to the eventual oxidation of vitamin C by oxygen in the atmosphere. In addition, ascorbic acid is a water-solubility vitamin that means that a significant amount of vitamin C present in food can be lost by boiling and then discarding the cooking water. The formula for ascorbic acid is C6H8O6, It occurs as a white or slightly yellow crystal or powder with a slight acidic test, Ascorbic Acid is freely soluble in water; sparingly soluble in alcohol; insoluble in chloroform, ether, and benzene.

The amount of ascorbic acid can be determined by a redox titration with a standardized solution of iodine. The iodine is reduced by the ascorbic acid to form iodide. As shown in the other half of this redox equation. The titration endpoint is reached when a slight excess of iodine is added to the ascorbic acid solution. Vitamin C deficiency leads to scurvy, a disease characterized by weakness, small hemorrhages throughout the body that cause gums and skin to bleed, and loosening of the teeth. Vitamin C can not be synthesized through body cells, nor does it store it. It is therefore important to include plenty of vitamin C-containing foods in daily diet. vitamin C toxicity is very rare, because the body can not store the vitamin however, amounts greater than 2000 mg/day are not recommended because such high doses can lead to stomach upset and diarrhea. The minimum daily requirement is 30 mg. Well-balanced diets provide adequate amounts of the vitamin as measured by the Recommended Daily Allowance (RDA) of about 75 mg per day for adults (aged 15 or older), less for children, and more for pregnant and lactating women. The National Academy of Sciences recommends the consumption of 60 mg of ascorbic acid per day. The Federal Food and Drug Administration has adopted the recommended dietary allowance (RDA) of 60 mg/day A very small daily intake of vitamin C (10-15 mg/day for an adult) is required to avoid deficiency and stave off scurvy. However, there has been and continues to be, vigorous debate on what the optimum daily intake of vitamin C is. Some have argued that 200 mg/day is an optimal daily intake for adult humans.

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1. Transfer iodine solution to a 1L volumetric flask, making sure to rinse all traces of solution into the volumetric flask using distilled water, completed the volume up to the mark.
2. Preparation of 0. 5% starch indicator solution: Soluble starch (0. 25gm) to a 100 mL conical flask or beaker and 50 mL of distilled water was added. Solution heated with stirring at 79 0C for 5 minutes, care must be taken not to exceed the stated temperature. Allow the solution to cool to room temperature.
3. Preparation of food/drink sample: Industrial Packaged fruit juices Orange, Pineapple, Lemon, Tmrhend and Apple (Miso), Pepsi (Khaleel kadhai), Red grapes(Nektar), Seven-up (Kufa), Pomegranate (Linda), Tmrhend (Toti), Orange (Dalia), and Granules peach may also need to be strained through cheesecloth if it contains a lot of pulp or seeds.

Vitamin C tablets – type Krueger according to bulletin declared only that all (1) gm contains (45) mg of vitamin C, but the results we obtained the concentration is (69. 95) mg in (1) gm, an increase of about (25) mg. Either vitamins fruits tablets – type junior according to bulletin declared only that all (1) gm contains (8. 8) mg of vitamin C but we have received is (19. 995) mg in (1) gm, an increase of more than double. Where the study showed that the Tmrhend juice (Miso) was vitamin C focus as the results we obtained (25. 7) mg/100 ml, but according to the bulletin, attached descent rate and quality (1. 68) mg/100) ml, either alimonadah juice (Miso) was its focus as the results we obtained (15. 4)mg/100 ml, but according to the bulletin attached descent rate and quality (0. 1) mg/100 ml. comparing these results with a focus located on the packaging these juices, showing clearly that there was a difference in the percentage concentration of the company to company, And also because of industrial juices and wrong storage methods. The handling and preparation of food products adversely affect the quality of vitamin C in food. since it is vulnerable to heat, oxygen and acid, temperate, and alkalinity mediums. With regards to the manufacture of juices, the keeper's airtight containers made of sheet metal or glass do not cause the loss of what remains of vitamin C as a result of manufacturing processes only about 10 % while keeping cardboard containers, whether, with paraffin layer or polyethylene, they lead to the loss of around 75 % of the past three weeks, even if keeping it in the fridge because these containers do not prevent the access of oxygen to juice and oxidize it, in addition to the work of the upper-packaged juice or occupied by air to oxidize the proportion of juice again, while the addition of carbon alkalinity of the damage vitamin juice damage entirely.

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