Food Lipids: Chemistry, Nutrition, and Biotechnology

Solid:
Liquid:
SSS, 33.3%
OOO, 8.3%
OOL, 24.99%
OLL, 24.99%
LLL, 8.3%
The segregation of saturated fatty acids into trisaturated species is necessarily
accompanied by a corresponding tendency for unsaturated fatty acids to form triunsaturated
species [47].
VIII. KINETICS OF CHEMICAL INTERESTERIFICATION
Random interesterification is usually conducted until equilibrium has been reached.
There are many conflicting reports in the literature concerning interesterification reaction
rates. Coenen [41] stated that once a sufficient concentration of catalyst in
solution had been reached in the reaction mixture, the actual interesterification reaction
was extremely fast, requiring only a few minutes, unless operations had to
proceed at very low temperatures. The kinetics were modeled in several ways to
support this theory. The first example was a model system consisting of short chain
fatty esters (C8, C10) of ethylene glycol (Fig. 9). The induction period was long,
yet the reaction itself was rapid, even at 32�C. In the second example, interesterification
of palm oil was evaluated using solid fat content determinations (Fig. 10).
The reaction rate was faster at higher temperatures. These data confirm that an activation
period is indeed required and agree with Weiss et al. [24] and Rozenaal [11],
who reported that the catalyst formation phase was longer than the interesterification
Figure 9 Theoretical interesterification kinetics of glycol esters of C8 and C10 as a function
of time and temperature. 42�C (�); 37�C) (●); 32�C (▫). (Adapted from Ref. 41.)
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.