Chapter 2 The nutrients in food
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I have questions on the Vit C content of cabbage experiment.
1. What is the dye factor for? Is it some kind of comparison?
2. Is the enzyme ascorbic acid oxidase present all the time in cabbage. Doesn't it just destroy all the Vit C?
Ulex writes …
Ascorbic acid is a reducing agent; the dye used in this experiment oxidises ascorbic acid. The dye factor tells you how much ascorbic acid, in mg, reacts with 1cm3 of the dye and thus enables you to work out how much ascorbic acid is present in the sample you are titrating.
The enzyme is present in the cells of cabbage all the time, but teh internal structure of the cells keeps the enzyme and the Vitamin C apart. When you homogenise the cabbage you break up the cells and free up the chemicals so that they can mix.
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updated: 19 September 2003
