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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 2 Mechanism by which one phenolic free radical scavenger can inactivate two<br />

peroxyl radicals.<br />

copherylquinone <strong>and</strong> the regeneration of tocopherol (Fig. 4) [6]. Formation of tocopherylquinone<br />

is also thought to occur by the transfer of an electron from a tocopheroxyl<br />

radical to a phospholipid peroxyl radical, to form a phospholipid<br />

peroxyl anion <strong>and</strong> a tocopherol cation. The tocopherol cation hydrolyzes to 8�-hydroxytocopherone,<br />

which rearranges to tocopherylquinone (Fig. 5) [8].<br />

Under condition of more extensive oxidation, high concentrations of peroxyl<br />

radicals can favor the formation of tocopherol–peroxyl complexes. These complexes<br />

can hydrolyze to tocopherylquinone. Of less importance are interactions between<br />

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

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