Palm oil fractionation and carotene extraction
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Date
1978-04
Authors
Boey, Peng Lim
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A novel method of fractionation of vegetable, animal and fish oils
and in particular palm oil is described. The method involves the
a·ddition to the oils a medium made up of two common solvents. On
centrifugation the olein and stearin are separated by tne medium in the
middle. Twelve solvent systems or media which are made up of a combination
of two from eight common solvents viz. water, propylene glycol,
glycerine, acetone, ethanol, n-propanol, isopropanol and butanone are
found to be effective in olein-stearin separation. However, the
water-isopropanol system was studied in great details. The fractionation
process can oe carried out at any suitable temperature and is
independent of the method of crystal] isation of the oil. Fractionation
of the Special Prime Bleached (SPB) crude palm oil at 16°C using the
water-isopropanol system, yielded an olein fraction with a cloud point
of 4.8°C. The used medium can be re-used up to seven times. Fractionation
of hydrogenated palm kernel oil yielded a stearin fraction similar in
melting characteristic (36°C) to that of cocoa butter. This fractionation
process could also be extended with suitable modifications to include
degumming and neutralisation. The olein fractions obtained after
fractionation were found to be free from phosphatides and the free
fatty acid content was reduced to as low as 0.02%. The development
of this fractionation into a continuous process has been demonstrated
using the Alfa-Laval LAPX 202 Separator. From the fractionation study of the various oil from hybrid palms,
the Interspecific Hybrid F1 ( E. oleifera x E. guineensis (Pisifera based) ) was found to be promising. When the oil was fractionated at
15°C, the yield of olein was 87.7%, its cloud point 1.7°C and its iodine
value 66.7 and the total unsaturation was 63% whilst the corresponding
stearin obtained has a melting point of 49.0°C .
Fractionation of crude palm oil using density graqients yielded
six stearin fractions of different melting-characteristics (47.5°C to
55.3°C) and fatty acid composition (unsatur~tion 48.4% to 34.9%).
Besides fractionation, this finding could also be applied to the
determination of the olein content of palm oil. A reasonable relationship
was found to exist between the percentage of olein thus determined at
29°C and the fatty acid composition. A mixture of 80% water and 20% isopropanol containing sodium
hydroxide was found to effect neutralisation of palm oil and palm kernel
oil without the formation of emulsion, while minimising oil loss to
4.8% . Oil loss using aqueous sodium hydroxide was 7.6% .
A study on the synergistic effect-of lecithin with various common
antioxidants in stabilising oils showed that the amount of antioxidants
used could be very much reduced. It was found that when 0.05% of
lecithin was added only 1/8 of the original concentration of buty
hydroquinone (TBHQ) or 1/20 of the original concentration of butylated
hydroxy anisole (BHA) or butylated hydroxy toluene (BHT) when used
singly was required to give the same AOM-stabil ity.
Normal refining of crude palm oil destroys the carotenes present in
it. Here, a method of extracting the carotenes with locally produced activated carbons is described. The carotene extract obtained (using S51 I carbon) is about six times that of the concentration of carotene in
the original oil. The extracted carotenes are biologically active and
not toxic to animals as confirmed by feeding experiments using albino
rats and a histological study of their organs. The sorption study on the
activated carbons shows that carbons of pH around 10.8 ~ith large surface
area and possessing large numbers of mesopores are suitable for carotene
extraction.
Description
Keywords
Palm oil