Konu: The Importance of Food pH in Commercial Canning Operations

Introduction
The pH value of a food is a direct function of the free
hydrogen ions present in that food. Acids present in foods release
these hydrogen ions, which give acid foods their distinct sour
flavor. Thus, pH may be defined as a measure of free acidity.
More precisely, pH is defined as the negative log of the hydrogen
ion concentration.
Therefore, if a food has a pH value of 3, then the
concentration of hydrogen ions present in that food is equal to 10-3
(0.001) moles/liter. If the pH value is 6, then the concentration of
hydrogen ions equals 10-6 (0.000001) moles/liter.
These examples show the concentration of hydrogen ions
decreases as the pH value of the food increases. This explains
why a low-pH food is a high-acid food and vice versa.
The range of pH is commonly considered to extend from
zero to 14. A pH value of 7 is neutral, because pure water has a
pH value of exactly 7. Values less than 7 are considered acidic,
while those greater than 7 are considered basic or alkaline. Figure
1, below, shows the approximate pH values of several types of
foods. A more detailed list is given in Appendix 1. A few foods,
such as egg whites, sweet corn and some baked goods may be
basic. Most foods are naturally acidic, with a pH value less than
7.0. Even so, the pH value of a particular food may have a
dramatic effect on the type of processing needed to safely
preserve it.
The Importance of Food pH in Commercial Canning Operations
William McGlynn
Extension Horticultural Foods Scientist

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