Food Lipids: Chemistry, Nutrition, and Biotechnology

Table 4 Fatty Acid Composition of Typical Lipid Emulsions and Medium
Chain Triacylglycerol
Fatty acid
Composition (%)
FE emulsion 73403 Intralipid 20% MCT
8:0 27 — 65–75
10:0 10 — 25–35
12:0 — — 1–2
16:0 7 13 —
18:0 3 4 —
18:1n-9 13 22 —
18:2n-6 33 52 —
18:3n-3 5 8 —
Other 2 1 1–2
MCT, Medium chain triacylglycerol.
for specific applications. Unfortunately, many enzymatically synthesized SLs are not
commercially available, although the potential is there. This technology needs to be
commercialized.
3. Enzymatic Synthesis
a. Lipases in Fats and Oils Industry. Triacylglycerol lipases, also known as
triacylglycerol acylhydrolases (EC 3.1.1.3), are enzymes that hydrolyze TAGs to
DAGs, MAGs, free fatty acids (FFAs), and glycerol. They can catalyze the hydrolysis
of TAGs and the transesterification of TAGs with fatty acids (acidolysis) or direct
esterification of FFAs with glycerol (47–49). Annual sales of lipases presently account
for only $20 million, which corresponds to less than 4% of the worldwide
enzyme market estimated at $600 million (50). Two main reasons for the apparent
misconception of the economic significance of lipases are as follows: (a) lipases have
been investigated extensively as a route to novel biotransformation, and (b) the diversity
of the current and proposed industrial applications of lipases by far exceeds
that of other enzymes such as proteases or carbohydrases (51).
Although enzymes have been used for several years to modify the structure
and composition of foods, they have only recently become available for large-scale
use in industry, mainly because of the high cost of enzymes. However, according to
enzyme manufacturers, progress in genetics and in process technology may now
enable the enzyme industry to offer products with improved properties and at reduced
costs (51). For lipases to be economically useful in industry, enzyme immobilization
is necessary to enable enzyme reuse and to facilitate continuous processes. Immobilization
of enzymes can simply be accomplished by mixing an aqueous solution
of the enzyme with a suitable support material and removing the water at reduced
pressure, after which small amounts of water are added to activate the enzyme.
Suitable support materials for enzyme immobilization include glass beads, Duolite,
acrylic resin, and Celite.
In spite of the obvious advantages of biological catalysis, the current level of
commercial exploitation in the oleochemical industry is disappointing, probably be-
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.