8 Production of Functional Lipids Containing
Polyunsaturated Fatty Acids with Lipase
Yuji Shimada, Akio Sugihara and Yoshio Tominaga
8.1 Introduction
Polyunsaturated fatty acids (PUFAs) have various physiological functions, and are
used as pharmaceutical substances, in cosmetics, food materials, and health foods.
For example, the ethyl ester of eicosapentaenoic acid (20 : 5n-3; EPA) has been used
in the treatment of arteriosclerosis and hyperlipemia since 1990 in Japan. Docosa-
hexaenoic acid (22 : 6n-3; DHA) plays a role in the prevention of a number of human
diseases, including cardiovascular disease (Kromhout et al., 1985), inflammation
(Lee et al., 1985), and cancer (Bravo et al., 1991; Stillwell et al., 1993). DHA
has also been reported to show an important function in the brain (Uauy and De
Andraca, 1995) and retina (Nuringer et al., 1984), and to accelerate the growth
of preterm infants (Carlson et al., 1993; Lanting et al., 1994). For this reason,
tuna oil containing DHA has been used as a food material, an ingredient of infant
formulas, and a health food. Arachidonic acid (20 : 4n-6; AA) is a precursor of local
hormones (prostaglandin, thromboxanes, and leukotrienes) involved in the AA cas-
cade (Minno et al., 1987), and accelerates the growth of preterm infants, as does
DHA (Carlson et al., 1993; Lanting et al., 1994). An AA-rich oil produced by a
microorganism has begun to be used in a formula for preterm infants in Europe
since 1998.c-Linolenic acid (18 : 3n-6; GLA) is a precursor of AA, and is effective
for atopic eczema (Bordoni, et al., 1988; Fiocchi et al., 1994) and rheumatoid ar-
thritis (Jantti et al., 1989; Zurier et al., 1996). Thus, borage oil rich in GLA is
used as an ingredient of infant formulas and a health food.
The first generation of PUFA-containing oils were natural oils themselves, but the
triglyceride structure and fatty acid composition were not always the most suitable
for humans. Thus improvement of oils has been strongly desired, and the second
generation of PUFA oils has emerged. The second generation oils include single
cell oils produced from microorganisms and oils modified by lipases. Lipases cat-
alyze not only hydrolysis, but also esterification and transesterification, and are very
useful for the modification of natural oils. In this chapter, we describe the improve-
ment of PUFA-containing oils with lipases, especially the production of PUFA-rich
oils and highly absorbable structured lipids.
8.2 Production of PUFA-rich oils by selective hydrolysis
Oils containing higher concentrations of PUFA have the following advantages: (i)
greater physiological effects can be expected from even a small amount of intake; (ii)
Enzymes in Lipid Modification.Edited by Uwe T. Bornscheuer
Copyright2000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. ISBN: 3-527-30176-3
