EL highly enriched with either EPA or DHA or both EPA and DHAwere obtained
by transesterification reactions with concentrates of EPA and DHA, using Lipozyme
in a manner identical to that described previously for cod liver oil. Direct esterifica-
tion of the 1-O-alkyl-sn-glycerols with EPA and DHA resulted in homogeneous EL,
when using theCandida antarcticalipase. These reactions are demonstrated in
Scheme 5 for EPA. It was interesting to notice that the EL were apparently far
less prone to acyl migrations as compared to the TG under the transesterification
conditions. This is presumably related to the fact that only one of the primary
end-positions is now available for the lipase.
10.5 Phospholipids highly enriched with EPA and DHA
PL are major constituents of cell membranes, and play essential roles in the biochem-
istry and physiology of cell functions (Mead et al., 1986). PL in fish and marine
species are highly enriched with the long-chain n-3 type PUFA, 40–50 % content
of EPA and DHA not being uncommon in some PL classes in fish (Haraldsson et al.,
1993a). The n-3 PUFA presumably play significant roles in adjusting the membrane
10.5 Phospholipids highly enriched with EPA and DHA 179
Figure 3. The chemical structure of chimyl, batyl and selachyl alcohols.
Scheme 5. Lipozyme-catalyzed enrichment of 1-0-alkyl-2, 3-diacyl-sn-glycerols by transesterofoca-
topm reactopms (top) and direct esterification of 1-0-alkyl-sn-glycerols with EPA using CAndida antarc-
tica lipase (bottom). R1 refers to the 1-0-alkyl group composition. FOr further abbreviations see Scheme 1.