Analysing the vitamin C content in different fruit juices

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Title               : The Vitamin C Content in Fruit Juices

Name             : Yii Seng Ong

Date               : 28 August 2011

Class              : 12M15

Student ID    : 2011200378

Name of lecturer : Madam Ida Muryany binti Md.



  1. To determine and compare the concentration of vitamin C in different kind of fruit juices
  2. To determine and compare the concentration of vitamin C in freshly prepared fruit juices and carton fruit juices


  1. Vitamin C

            Vitamin C or also can be known as ascorbic acid is the elonic form of 3-oxo-L-gulofuranolactone. It can be synthesized from glucose or extracted from other plant sources such as blackcurrants, rose hips or citrus fruits. The empirical formula for vitamin C is C6H8O6. Other than that, the molecular weight for ascorbic acid is 176.1. Its melting point is about 190°C( with decomposition). The appearance is white to slightly yellowish crystalline powder. It is practically odourless, with a strong acidic property and a sour taste.


 Figure 1 : 2D structure of vitamin C                     Figure 2 : 3D structure of vitamin C

Generally, vitamins are a group of complex organic compounds which play an essential role in animal metabolic process but which the animal cannot synthesis. Vitamins do not provide energy however, in their absence the animal develops certain deficiency diseases or other abnormal conditions. Vitamins together with proteins, carbohydrates, fats and mineral salts are essential components of the food of animals. Certain animals can synthesis certain vitamins. All animals which need vitamin D can synthesis it from ergosterol in the presence of UV light. With the exception of vitamin D, human body cannot make its own vitamins and some cannot be stored. Therefore, one must obtain vitamins from a food on a daily basis. A person’s diet must provide all the necessary vitamins.

          Vitamin C is a water-soluble vitamin, meaning human’s body does not store it. We get what we need, instead, from food. Besides, man is one of the few mammals unable to manufacture ascorbic acid in his liver. Excess vitamin C is eliminated through urine once the body has used up what it needs. Therefore, it is important to consume adequate quantities of fruits and vegetables containing vitamin C on a daily basis. 

         Vitamin C plays important role in the body in many aspects, including : boosting the immune system, healing cuts and wounds, promoting healthy teeth and gums, protecting body against lifestyle diseases, improving eye’s health and enhancing the absorption of fundamental iron and zinc. Besides, vitamin C also is needed for the growth and repair of tissues in all parts of the body. It helps the body makes collagen which is an essential protein for making skin, cartilage, tendons, ligaments and vessels.

          Vitamin C is an antioxidant, like vitamin E, beta-carotene and many other plant-based nutrients. When our bodies transform food into energy, the free-radicals are produced naturally. These free-radicals can cause damage to the body. The build-up of free radicals over long time may contributes to aging process and can lead to occurrence of health disease such as cancer , heart disease and arthritis. However, the intake of antioxidants into the body can block some of the damage caused by the free-radicals by stabilising them.

         The most prominent role of vitamin C is its immune-stimulating effect, e.g., important for defending against infections such as common colds. It also acts as an inhibitor of histamine, a compound that is released during allergic reactions. Besides, as a powerful antioxidant as mentioned above, it also aids in neutralizing pollutants and toxins. Thus it is able to prevent the formation of potentially carcinogenic nitrosamines in the stomach due to consumption of nitrite-containing foods, such as smoked meat.

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  1. Vitamin C content in fruit

     The best readily available vitamin C source in fruit is kiwifruit. Fruits like

orange are the most renown source of vitamin C. Freshly squeezed orange juice contains 26%  of vitamin C. Fruit juice can provide up to 33% of the vitamin in children’s diet. In fact, both adults and children rely more on fruit juice than fresh fruit for their daily supply of vitamin C.

            Commercial fruit juices may have sugar and other substances added. They also usually pasteurized to prevent fermentation and spoilage. ...

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***** A very detailed account of the investigation written in a concise style. A clear understanding of background theory demonstrated with A level terminology used throughout. Data presentation and analysis is of a high standard.