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Encyclopedia of Physical Science and Technology EN010B-472 July 16, 2001 15:41

Natural Antioxidants In Foods

Eric A. Decker
University of Massachusetts

I. Free Radical Scavengers
II. Metal Chelators
III. Antioxidant Enzymes

GLOSSARY oxygen and nitrogen species. However, during the pro-
cessing of biological tissues into foods, the formation of
Antioxidant A compounds that can inhibit oxidative pro- oxidizing species can increase and antioxidant systems
cesses. can be overwhelmed leading to uncontrolled oxidative
Free radical A compound with an unpaired electron that reactions resulting in loss of quality, decrease in shelf-
can promote oxidative reaction. life, and formation of potentially toxic oxidation products.
Free radical scavenger A compound that can absorb a To protect food quality and safety, antioxidants are often
free radical to decrease the radical energy thus making added to processed foods. These antioxidants can be syn-
it less likely to cause oxidation. thetically derived compounds, such as butylated hydroxy-
Metal chelators Compounds that can bind metals and toluene and ethylene diaminetetraacetic acid. Concern
decrease their reactivity. over the use of synthetic food additives has driven the
Phenolic A group of chemical compounds primarily food industry to find effective natural antioxidants addi-
found in plants that act as antioxidant and are bene- tives that are derived from biological sources. In addition,
ficial to health. efforts to decrease oxidative deterioration have focused
on the development of food processing techniques that
preserve endogenous antioxidants and nutritional schemes
ATMOSPHERIC (TRIPLET) oxygen is a low energy that increase natural antioxidants in animal-derived
biradical (i.e., contains two unpaired electrons). How- foods.
ever, during metabolism of oxygen as well nitrogen, al- In addition to the association of natural antioxidants
terations can occur to produce highly reactive oxygen and with food quality, these compounds have also been as-
nitrogen species that will react with and cause damage sociated with health benefits. The association of the pro-
to biomolecules. In foods, this can cause oxidation of tective effects of fruits and vegetables in the diet against
lipids, pigments, vitamins, and proteins, leading to off- diseases, such as cancer and cardiovascular disease, has
flavor formation, discoloration, and loss of important nu- been established for years. Comprehensive reviews on the
trients. Foods,which are derived from a variety ofdifferent consumption of fruits and vegetables with cancer rates
biological tissues, contain a host of different antioxidant have shown that 60–85% of the studies have a statisti-
defense systems to prevent the damaging effect of reactive cally significant association with the decrease of cancer

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