11.2.2 Acidolysis between triacylglycerols and free fatty acids
with regiospecific lipases
The reactions between triacylglycerols and fatty acids withregiospecific lipasescan
be depicted as shown in Figure 3. This reaction has been used for the production of
CBE, Betapol, and other specific structured lipids (SSL). For a reaction between a
triacylglycerol (XXX) and a fatty acid (Y), there will be an equilibrium between the
three main triacylglycerol species: XXX,sn-YXX/XXY, andsn-YXY in the main
reaction scheme. Since the lipases aresn-1,3-specific, there will be no other isomers
formed theoretically. Provided that the lipases have the same specificity towards both
X and Y andsn-1 andsn-3 positions and that no side reactions occur, the content of
the three main species after equilibrium will only depend on the substrate molar
ratios and can be calculated theoretically. The following equations can be used
for the calculation:
XXXðmol%Þ¼400
ð 2 þSrÞ
2 ð^5 ÞYXX=XXYðmol%Þ¼200 Srð 2 þSrÞ
2 ð^6 Þ194 11 Modification of Oils and Fats by Lipase-Catalyzed Interesterification
Figure 2. Reaction schemes of enzymatic randomization by ester – ester exchange between two tria-
cylglycerols (LLL and MMM). The triacylglycerol species in each of the rectangles have the same pro-
portions if the lipases have the same specificity towards different fatty acids and the same preferences to
the three positions of the glycerol backbone.
Figure 3. Reaction scheme of lipase-catalyzed acidolysis between a triacylglycerol (XXX) and an acyl
donor (Y).