9.4.2 ABA-type sTAG
Pure ABA-type sTAG can be produced by several methods, including a two-step
reaction (Soumanou et al., 1998; Schmid et al., 1998) as shown in Equations (7)
and (8).
TAG + AlcoholR2-MAG + FA Esters (7)2-MAG + FARABA-type sTAG + H 2 O (8)The first step [Equation (7)] is an alcoholysis (ethanolysis) of TAG (triolein, trili-
nolein, peanut oil or fish oil) in an organic solvent (e.g. methyl-t-butyl ether or acet-
one) using a 1,3-regiospecific lipase. 2-MAG was obtained in up to 80–90 % yield at
>95 % purity by crystallization. The second step [Equation (8)] is an esterification
of these 2-MAG which in hexane, again with 1,3-regiospecific lipase, gave almost
pure ABA-type sTAG. For example, Betapol (OPO) was obtained in>78 % yield
and 96 % purity.
The author’s group reported a chemo-enzymatic synthesis of C 8 (EPA)C 8 ,as
shown in Equations (9) and (10) (Rosu et al., 1999a).
164 9 Lipase-Catalyzed Synthesis of Structured Triacylglycerols
Figure 5. Effect of water activity (aw) control during vacuum application on molar yield of C 8 C 8 (EPA)
[and/or (EPA)C 8 C 8 ] (Han and Yamane, 1999). The reaction was performed without vacuum at normal
pressure in a closed vessel (*), reaction under 3 mmHg pressure applied at 9 h (indicated with a vertical
arrow) thereafter with no awcontrol (&), and reaction under 3 mmHg applied at 9 h (indicated with a
vertical arrow) thereafter with awcontrol at 0.07–0.17 (~).