Food Lipids: Chemistry, Nutrition, and Biotechnology

Figure 48 Enzymatic production of long chain aldehydes and ketones.
with water to disrupt the oil-bearing cells, followed by centrifugation to separate the
oil from the solids and the aqueous phase (350).
Extensive mechanical rupturing of the cells of oil-bearing seeds is the prerequisite
for efficient oil extraction (351). Several reports have suggested the use of
enzymes for the rupture of the plant cell walls to release the oil contained in the cell
prior to recovery of the oil by mechanical pressing, solvent extraction, or aqueous
extraction. Plant cell walls are generally composed of unlignified cellulose fibers to
which strands of hemicellulose are attached; the cellulose fibers are often embedded
in a matrix of pectic substances linked to structural protein (352). Since substantial
differences are observed in the polysaccharide composition of the cell walls of different
plant species (Table 10), different combinations of cell wall–degrading enzymes
(carbohydrases and proteases) have to be used for individual seeds or fruits
(107,352,353). Enzymes used in cocktails for cell wall degradation include amylase,
cellulase, polygalacturonase, pectinase, hemicellulase, galactomanase, and proteases
(107,353).
Enzyme pretreatment followed by mechanical expelling for improved oil recovery
has been used for rapeseed (107,354) and soybean (355). Typically, treatment
of flaked rapeseed with commercial enzyme preparations (SP 249, Novo Nordisk
Figure 49 Preparation of dihydroxy fatty acids by epoxide hydrolase.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.