Glyðmol%Þ¼100 n^3ð 1 þnÞ
3 ð^12 ÞThe relationship between the four species and the substrate molar ratio (n) can be
depicted in Figure 5 to illustrate the tendency. It can be seen that the highest content
ofmonoacylglycerolscan be obtained at the substrate molar ratio (n) of 2 with the
content of 45 % at reaction equilibrium. Further improvements of the yield of mono-
acylglycerols have to resort to other techniques such as solid-liquid glycerolysis orin
situseparations, which was summarized in a review by Bornscheuer (1995). These
calculations can be used as a guide for process design or experimental set-up. The
calculation is based on the reaction at equilibrium and those assumptions as the
premise, such as absolute nonspecificity of lipases and no preferences toward cer-
tain fatty acids. Therefore, again calculation from these equations cannot be used
without limitations.
196 11 Modification of Oils and Fats by Lipase-Catalyzed Interesterification
Figure 4. Reaction schemes of enzymatic randomization by alcoholysis between a triacylglycerol
(LLL) and a glycerol (Gly). The acylglycerol species in each of the rectangles have the same proportions
if the lipase has the same preference to the three positions of the glycerol backbone.
Figure 5. The relationships between substrate molar ratio (n) and the contents of acylglycerol species at
equilibrium during reactions catalyzed by nonspecific lipases, which are assumed to have the same pre-
ference to the three positions. LLL, triacylglycerol; DAG, diacylglycerol; MAG, monoacylglycerol; Gly,
glycerol.