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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 33 Preparation of concentrates of �-linolenic acid (GLA) via lipase-catalyzed selective<br />

esterification of fatty acids from borage oil or evening primrose oil with n-butanol.<br />

taining the two CLA isomers in equal amounts was subjected to esterification with<br />

dodecanol using lipase from Geotrichum c<strong>and</strong>idum as catalyst (277). This resulted<br />

in selective esterification of the cis-9,trans-11 isomer <strong>and</strong> enrichment of the trans-<br />

10,cis-12 isomer in the unesterified fatty acid fraction. Separation of the two fractions<br />

by molecular distillation yielded an ester fraction containing 91% cis-9,trans-11 isomer<br />

<strong>and</strong> a fatty acid fraction containing 82% trans-10,cis-12 isomer.<br />

Selective hydrolysis of high-erucic oils, catalyzed by lipases from Geotrichum<br />

c<strong>and</strong>idum (278,279) <strong>and</strong> C<strong>and</strong>ida rugosa (279,280), leads to enrichment of erucic<br />

acid in the unhydrolyzed acylglycerols, as outlined in Fig. 35. The diacylglycerols<br />

formed by hydrolysis using the lipase from C<strong>and</strong>ida rugosa contain as much as 95%<br />

of erucic acid (279). In the esterification of individual fatty acids with n-butanol,<br />

catalyzed by lipase from Geotrichum c<strong>and</strong>idum, erucic acid is discriminated against<br />

(281,282).<br />

The selectivity of commercial lipases towards very long chain monounsaturated<br />

fatty acids (VLCMFAs) in hydrolysis <strong>and</strong> transesterification reactions has been determined<br />

using high-erucic oils from white mustard (Sinapis alba), oriental mustard<br />

(Brassica juncea), <strong>and</strong> honesty (Lunaria annua) seeds (127). The lipases from C<strong>and</strong>ida<br />

rugosa <strong>and</strong> Geotrichum c<strong>and</strong>idum selectively cleave the C 18 fatty acids from<br />

Figure 34 Enrichment of �-linolenic acid (GLA) from borage oil fatty acids by selective<br />

esterification with n-butanol, catalyzed by triacylglycerol lipase from Rhizomucor miehei<br />

(Lipozyme) according to Ref. 275: reaction temperature, 60�C; reaction time, 2 hours; degree<br />

of esterification, 91%.<br />

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

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