Question:
I am doing an experiment on vitamin C and oxidation. I
have an experiment set up, and i know oxidation is due to the reaction
between oxygen and vitamin C, and that the vitamin looses hydrogen
molecules. I am wondering though, what exactly happens between the oxygen
and vitamin C to cause loss of hydrogen molecules, and why does putting
your orange juice in the fridge slow down oxidation?
The second question is easier to answer. The rule of thumb chemists use in
the absence of any other data is that the rate of a chemical reaction
approximately doubles for every 10 C. increase in temperature. So cooling
orange juice from 25 C. to say 0 C. would decrease reactions by about 2.5
times.
Replies:
Your first question: How does ascorbic acid (vitamin C) work is much
more complicated, and a quick Google search only made that more evident.
There does not seem to be any simple chemical reaction(s) for the quenching
of free radical chain reactions by vitamin C or other anti-oxidants for that
matter. One can write down some "paper" chemical reactions, but seldom is
the body's biochemistry so simple. I think it is safe to say that the exact
mechanism is not known.
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