Practical investigations
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I was investigating the content of Vitamin C in orange. I had made some orange juice and then did an experiment. I would really appreciate if you could tell me how much Vitamin C there is in 10 ml of orange juice. I searched on the internet and I don't feel so confident about the information given there. Also I would really appreciate if you could inform me about how much Vitamin C I lose when I am making orange juice: I mean how much do I lose in the residue that is left after making juice - those membranes and all that inside orange that is not part of a juice.
Igloo says ....
A typical freshly made sample of orange juice contains about 1.5-2.5 mg of vitamin C in each 10 ml of juice. This value depends of course on the variety and age of the oranges used.
Using a machine to extract the juice from oranges tends to break up the cell walls and allow the enzyme, ascorbic acid oxidase, to mix freely with the juice As a result degradation of the vitamin C begins almost immediately, but it is likely that most of the vitamin C remains if the juice is drunk immediately afterwards, e.g. at breakfast. Commercial fruit juice - supplied in bottles and cartons - contains antioxidants which serve to prevent the vitamin C degradation from taking place as rapidly.
To answer your second question, when the juice is separated from the pulp, virtually all the vitamin C is retained within the juice. The pulp largely consists of insoluble cellulose material.
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Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
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updated: 09 September 2007
