Food preservation principles

Reduction-oxidation (or short: Redox) potential is an indication of the oxidation state of a product. Oxidation state refers to the balance between oxidation and reduction in a food product. Oxidation is the loss of electrons, and reduction is the gain of electrons. Foods that are most sensitive to oxidation-reduction potential (ORP) are those with high moisture content, as water molecules can easily give away and accept electrons, as well as foods like nuts and oils, which posess free radicals. Free radicals are molecules with unpaired electrons that react quickly and seek out other electrons to pair with. During this process, free radicals can oxidize the fatty acids in fats, which can lead to off-flavors and off-odors, as well as a decrease in nutritive value.

The redox potential in food can be controlled by adding antioxidants such as ascorbic acid or vitamin E to the product, limiting the amount of oxygen available to the product, or controlling the temperature and humidity.

Redox potential meters can be used to constantly monitor the product and adjust processing parameters as needed.