Studies on palm oil with special reference to interestterification
Abstract
Interesterification which can be considered as the removal of
fatty acids at random from glyceride molecules, the shuffling
of these acids and their replacement of the glyceride molecules,
has been investigated for palm oil, palm oil fractions and palm
oil mixed with other vegetable oils. The reaction has been
effected at 90
C in the presence o£ sodium methoxide as a
catalyst. Pancreatic lipolysis has been ernployed to check the
completeness of the reaction. On complete randomisation,
the fatty acid composition of the 2-position is the same as that
of the whole fat either before or after interestelification.
The changes in the glyceride composition resulting from
interesterification have been exarnined by various standard
techniques. Silver ion thin layer chromatography which
separates glycerides according to their degree of unsaturation
has been used extensively. Using luethyl heptadecanoate as
an internal standard various component glycerides have been
quantified. GLG of glycerides has also been used to study the
changes in glyceride composition of fats containing a wide
range of fatty acid composition.
The application of thin layer chromatography, using methyl
heptadecanoate as an interncll standard, has also been extended
to deterrnine the esters formed during interesterification when
sodium methoxide is used as a catalyst.
The changes in physical properties which result from
interesterification have been determined by NMR (solids fat
content) and DSC (thermal behaviour).
Attempts to prepare a mixture of fats and oils containing
palm oil and / or palm oil fractions which simulates vanaspati
have been made. Many mixtures have been subjected to
interesterification and the physical properties of the products
have been investigated using NMR for all the mixtures and
DSC of selected mixtures. The SFC curve of each mixture
has been compared with that of vana spati.
useful mixtures are recognised.
Some potentially
Stereospecific glyceride analysis of various types of palm
oils has also been carried out using Brockerhoff's method.
This involves partial deacylation of the triacylglycerols,
isolation of the a,B-diacylglycerols, conversion of these
diacylglycerols to phospholipid derivatives and finally
stereospecific hydrolysis by Phospholipase A
2
from snake
venom, The possible component glycerides have then been
computed as suming a i-random, z- random, 3-random
distribution of the fatty acids found in each of these positions.
The results have been discussed in tenus of double bond
number and of carbon number: The latter has been compared
with results obtained by gas chromatography of the whole oil.
Type
Thesis, PhD Doctor of Philosophy
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