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Food Lipids: Chemistry, Nutrition, and Biotechnology

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4. 6-Ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (Ethoxyquin)<br />

Ethoxyquin may be used as an antioxidant for the preservation of chili powder,<br />

paprika, <strong>and</strong> ground chili at levels not to exceed 100 ppm (CFR 21, 172.140). It can<br />

be used in animal products at much lower levels. A primary role of ethoxyquin in<br />

the feed industry is the protection of carotenoids. Similarly, it stabilizes the color in<br />

paprika <strong>and</strong> chili powder. In oils, it exists primarily in the form of a radical that acts<br />

as a free radical terminator. Dimerization of this radical occurs in oil <strong>and</strong> will inactivate<br />

the antioxidant.<br />

5. Gallates<br />

Propyl gallate (PG), octyl gallate, <strong>and</strong> dodecyl gallate are approved for use as antioxidants<br />

in foods. PG, octyl gallate, <strong>and</strong> dodecyl gallate are, respectively, the npropyl,<br />

n-octyl, <strong>and</strong> n-dodecyl esters of 3,4,5-trihydroxybenzoic acid. Commercially,<br />

PG is the only gallate used in substantial quantity. A slightly water-soluble, white<br />

crystalline power, PG is used widely in foods for which lipid-soluble BHA, BHT,<br />

<strong>and</strong> TBHQ are not suitable. PG is not stable at high temperatures, degrading at<br />

148�C, <strong>and</strong> it is not suitable for frying applications. Octyl <strong>and</strong> dodecyl gallate are<br />

more lipid soluble, more heat stable, <strong>and</strong> have better carry-through. Gallates are sold<br />

as mixtures with metal chelators because they will form undesirable, dark-colored<br />

complexes with iron <strong>and</strong> copper [3]. Gallates act synergistically with primary antioxidants<br />

<strong>and</strong> some secondary antioxidants, <strong>and</strong> are often included in mixed antioxidant<br />

preparations.<br />

6. Tocopherols<br />

�-, �-, �-, �-Tocopherols <strong>and</strong> the corresponding tocotrienols (vitamin E homologs)<br />

are natural, monophenolic antioxidant constituents of vegetable oils. Tocopherols are<br />

described in detail in Section III.B. (Natural Antioxidants).<br />

7. Erythorbic Acid <strong>and</strong> Ascorbyl Palmitate<br />

Erythorbic acid (D-ascorbic acid) is often used as an antioxidant in fruits <strong>and</strong> as a<br />

curing accelerator in cured meats [2]. It is very soluble in water <strong>and</strong> insoluble in oil.<br />

It has Generally Recognized as Safe (GRAS) status with the U.S. <strong>Food</strong> <strong>and</strong> Drug<br />

Administration, but unlike L-ascorbic acid, it is not a natural constituent of foods. It<br />

has minimal vitamin C activity.<br />

Ascorbyl palmitate <strong>and</strong> ascorbyl stearate are synthetic derivatives of ascorbic<br />

acid. Ascorbyl palmitate is used in fat-containing foods because its solubility in<br />

hydrophobic media is superior to that of ascorbic acid <strong>and</strong> its salts; it is still fairly<br />

insoluble, however, <strong>and</strong> requires the aid of solubilizing magnets <strong>and</strong>/or high temperatures<br />

for solubilization [3]. Ascorbyl palmitate is usually used in combination<br />

with tocopherols. Ascorbyl palmitate has GRAS status, <strong>and</strong> the United States imposes<br />

no restrictions on usage levels. Ascorbyl palmitate is hydrolyzed by the digestive<br />

system to provide nutritionally available ascorbic acid <strong>and</strong> palmitic acid, but health<br />

claims cannot be made for its vitamin C contribution [13].<br />

B. Natural Antioxidants<br />

Extensive research has been dedicated to identification of antioxidants from various<br />

natural sources. Ascorbic acid <strong>and</strong> tocopherols are the most important commercial<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

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