Ascorbic acid (vitamin c) vs. citric acid
On Jun 6, 4:26 pm, "The Joneses" > wrote:
> Gentle friends: here's the answer to the questions I raised a few weeks ago:
>
> From: Elizabeth Andress
>
> "Why can't we substitute ascorbic acid (vitamin C) for citric acid (sour
> salt) or lemon juice for acidifying canned goods? And if it is possible,
> what is the substitution rate?"
>
> The quick answer is that it cannot be substituted because there are no
> established levels to provide the proper pH control in the canned foods
> where we have it required to assure safe boiling water processing instead of
> pressure processing.
>
> Ascorbic acid is not as efficient of an acidifier for the needed purposes
> (decreasing the pH of the food tissue). It is more expensive (in pure form)
> and the economics would then be compounded by needing to use more. For
> acidifying tomatoes, for example, the researchers worked out citric acid,
> lemon juice and vinegar options, but did not determine an acidification
> amount for ascorbic acid. There is no general conversion factor; different
> amounts would have to be tested in the actual food to be acidified. Foods
> contain natural components that can cause buffering with different acids in
> solution, and thereby prevent desired pH changes until a threshold is
> reached.
>
> I was not in the profession when the tomato acidification studies were done,
> but there could have also been some decision-making related to the fact that
> pure ascorbic acid was not very available to consumers so it was not
> considered. Three acidulants that were known to be effective food acidifiers
> and available to consumers were used. It is my understanding, however, that
> the reasoning has mostly to do with the fact that it is (and was) known that
> ascorbic acid is not known to be an effective acidifier in the foods being
> studied, fairly large amounts would be needed and there is a substantial
> cost difference compared to the chosen compounds.
>
> Citric acid is by far the most preferred and commonly used acidulant in the
> food processing and food canning industry.
>
> (And on the other hand, for many foods, ascorbic acid is a more effective
> anti-darkening agent than citric acid.)
>
> Elizabeth
>
> Elizabeth L. Andress, Ph.D.
> Project Director, National Center for HFP
> Professor and Extension Food Safety Specialist
> Department of Foods and Nutrition
> The University of Georgia
> 208 Hoke Smith Annex
> Athens, GA 30602-4356
> Phone: (706) 542-3773
> FAX: (706) 542-1979
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