Physico-chemical properties and characteristics of palm oil
Abstract
A survey of the literature revealed that most
palm oil imports carried the exporter's
specifications which created undue disputes that took
long periods to settle while the oil remained stored
under varying conditions at the point of destination;
that such imports were likely to be affected by
certain conditions of storage, transportation and
handling; and that no comprehensive studies had been
carried out to establish critical parameters that
could be used to characterise these imports and hence
provide a correct assessment of their market value
and appropriate tax, valuation in Kenya.
Palm oil samples from eight ex-Malaysia and
Indonesia shipments were collected from twenty-three
storage tanks at Mombasa port over a period of ten
months. The objective was to investigate the
characteristics of the oil in relation to possible
effects of handling, storage and transportation.
Mean density and refractive index when
determined at 50 ± O.l°C were found to be 0.8905 g/ml
and 1.4548, respectively. The iodine value and
softening point'were found to be 52.2 and 36.8°C,
respectively; whIle saponification value and
unsaponifiable matter content fluctuated around 197
mgKOH/g and 0.43%, respectively. Further
investigations with unsaturated fatty acids using the
Wij's iodine addition method revealed that the iodine
value (Y) for varying amounts of palm oil (X) can be
corrected using the equation: Y = -0.6203X + 52.666,
thus enabling an optimum standardization of the
weight range (0.31 < X < 1.21 g) of the oil for
testing. The content of carotenoids (expressed as
beta-carotene) was found to be 496 + 21 ppm; while
the free fatty acid content (as palmitic acid
equivalent and volatile matter were 3.47% and 0.12%,
respectively.
The values of density, softening point,
saponification value and refractive index were
generally higher t~an those reported from palm oil
surveys in Malaysia; while refractive index, iodine
value. - free fatty acid content. unsaponifiable
mat.t.er-,' carotenoids content and volatile matter were
lower. A study of the variation of viscosity of palm
oil. measured at temperatures between 25 and 90°C
yielded data which gave two regression lines that
intersected at 48.1°C, a valhe taken as the critical
temperature for.viscous flow of-palm oil.
These results can be used as reference
properties for -the grading of palm oil imports as
well as correct tax'valuation; and for categorizing
those imports that may require further processing in
this country. Strategies and priorities have also
been proposed for further investigations
concentrating on the iodine value, carotenoids
content and the viscosity-temperature relationship,
as critical parameters that can be used to assess
palm oil imports. In this way constraints on revenue
collection by the relevant tax agencies will be
identified and alleviated.
Citation
MScPublisher
School of Biological Sciences, University of Nairobi
Description
Degree of Master of Science