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FIG. 6. Effect of Lipozyme content on the initial rate of esterification of
glycerol with caprylic acid. The initial reaction rate was defined by the
conversion of caprylic acid at 15 min. For reaction conditions see Fig-
ure 2. For manufacturer see Figure 1.
The yields of 1,3-DAG synthesis were comparable to those
of the other enzymatic methods (10–12). Higher yields can
be expected if the method is optimized for each FA employed.
This direct method has the advantage of starting from the
cheapest reactants without employing organic solvents as re-
action media.
Chemical synthesis of 1,3-dicapryloyl-2-eicosapen-
taenoylglycerol. Purified 1,3-dicapryloylglycerol (95%) was
used for the chemical synthesis of the structured glyceride
with an eicosapentaenoyl group in position 2. The yield of
1,3-dicapryloyl-2-eicosapentaenoylglycerol after purification
was 42%. The purity of the product was checked by GC and
HPLC analysis. GC analysis could differentiate triacylglyc-
erols according to their molecular weights only, giving 98%
purity for the product, but two positional isomers, 1,3-di-
capryloyl-2-eicosapentaenoylglycerol and 1,2-dicapryloyl-3-
eicosapentaenoylglycerol, were included. Silver ion HPLC
analysis was used to determine the ratio of the two isomers.
The ratio of 1,3-dicapryloyl-2-eicosapentaenoylglycerol to
1,2-dicapryloyl-3-eicosapentaenoylglycerol (and/or 1-eicosa-
pentaenoyl-2,3-dicapryloylglycerol) was 9:1.
16. Srisiri, W., H.G. Lamparski, and D.F. O’Brien, Syntheses of
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Catalyzed Transesterification Between Eicosapentaenoic Acid
Ethyl Ester and Tricaprylin by Silver Ion High-Performance-
Liquid Chromatography and High-Temperature Gas Chroma-
tography, J. Am. Oil Chem. Soc. 76:31–39 (1999).
ACKNOWLEDGMENTS
Novo Nordisk A/S is acknowledged for the generous gift of the en-
zyme for this study. Roxana Rosu is a recipient of a scholarship for
foreign students from the Ministry of Culture and Education of Japan.
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[Received November 23, 1998; accepted March 2, 1999]
JAOCS, Vol. 76, no. 7 (1999)