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I have read that vitamin C is highly sensitive to light. So, how could parsley, for instance keep its vitamin C as it's flooded with sunlight?

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up vote 3 down vote accepted

UV light promotes the photo-oxidation of ascorbic acid (AsA) to dehydroascorbic acid (DHA).

enter image description here

DHA can be reduced to AsA by a specific dehydrogenase using reduced glutathione as reductant. I'm pretty sure that all cells are able to carry out this recycling of ascorbate.

Interestingly, in plants it appears that ascorbate acts as an electron donor to photosystem II (which is equivalent to it being oxidised).

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Thanks a lot for that! So would it be correct to say that parsley only contains DHA? (Or most of it) (AsA should logically have been already reduced just after the DHA syntheses) – Guillaume Combot Feb 7 '14 at 18:42

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