Food Lipids: Chemistry, Nutrition, and Biotechnology

Figure 22 Preparation of wax esters by lipase-catalyzed esterification of fatty acids with
long chain alcohols.
Butyl esters of fatty acids are useful as lubricants, hydraulic fluids, biodiesel
additives, and plasticizers for polyvinylchloride. Butyl oleate has been obtained in
high yields by lipase-catalyzed esterification of oleic acid with n-butanol (158).
Long chain alkyl esters of ricinoleic acid have been prepared in high yields by
lipase-catalyzed reactions, such as esterification of castor oil fatty acids with a long
chain alcohol or transesterification of castor oil triacylglycerols with a long-chain
alcohol (159).
Steryl esters of polyunsaturated fatty acids have been obtained by esterification
catalyzed by lipase from Pseudomonas sp., but at rather low reaction rates (160).
Recently, fatty acyl esters of phytosterols and phytostanols have been obtained at
high rates and in near-quantitative yields by esterification of the sterols with the fatty
acids or their transesterification with alkyl esters of fatty acids, both under vacuum
using Candida rugosa lipase as biocatalyst (161). Such steryl esters are being used
recently as blood cholesterol–lowering food supplements added to margarines (162).
4. Monoacylglycerols and Diacylglycerols
Lipase-catalyzed partial hydrolysis of oils (163,164) and esterification of fatty acids
with glycerol (165–174) have been carried out for the production of monoacylglycerols
(Fig. 24). Lipase-catalyzed esterification of glycerol with fatty acids under
vacuum provides symmetrical 1,3-diacylglycerols in good yields (175). Moreover,
lipase-catalyzed transesterification of glycerol with an alkyl ester of a fatty acid
(170,171) or of triacylglycerols with an alcohol, such as ethanol (176) or n-butanol
(177), provides good yields of monoacylglycerols.
Interesterification (glycerolysis) of triacylglycerols with glyceroglycerol, catalyzed
by lipases, as shown in Fig. 25, has been by far most successful for the
preparation of monoacylglycerols (178–187). Diacylglycerols have also been prepared
in high yields by glycerolysis of hydrogenated beef tallow, catalyzed by lipase
from Pseudomonas sp. (188).
Figure 23 Preparation of wax esters resembling jojoba oil by alcoholysis of triacylglycerols
of oils high in erucic acid with very long chain alcohols, catalyzed by sn-1,3-specific triacylglycerol
lipases.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.