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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 3 Proposed reaction mechanisms for chemical interesterification: carbonyl addition<br />

<strong>and</strong> Claisen condensation. (Adapted from Ref. 30.)<br />

During an attack, a new triacylglycerol is not necessarily formed. The transition<br />

complex (glycerylate � fatty acid) will decompose, either to regenerate the original<br />

species <strong>and</strong> active catalyst or to form a new triacylglycerol <strong>and</strong> a new active catalyst<br />

ion. This process continues until all available fatty acids have exchanged positions<br />

<strong>and</strong> an equilibrium composition of acylglycerol mixture has been achieved [1]. Support<br />

for this mechanism was provided by Coenen [41] who presented the kinetics<br />

between a simple mixture of S 3 <strong>and</strong> U 3. The kinetics were described with six possible<br />

reactions between various triacylglycerol <strong>and</strong> diacylglycerol anions, with a rate con-<br />

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

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