Abstract:
ABSTRACT
Palm kernel oil has been deodorized using medicinal plants (fresh and dry
cinnamon leaves, fresh lemongrass) and the changes monitored using optical
(absorbance (ABS), surface reflectance (SR), laser induced fluorescence
(LIF)) and conventional (phosphor molybdate method using ascorbic acid)
techniques. Changes were again monitored when the oil was exposed to
sunlight with samples protected and not protected from ultraviolet radiation
(UV). The ABS measurements were conducted using a spectrophotometer
while for the SR measurements, white light source was focused into a two-
way optical fibre probe and the reflected light channelled into a spectrometer
on to the sample. The LIF was measured at longer wavelengths using a
spectrometer at 90o to a 445 nm laser source. Principal component analysis
was computed using the fluorescence data in discriminating between the
refined deodorized and refined non-deodorized oils. The ABS increased with
increasing deodorant mass while the SR decreased. The conventional
technique established an increase in antioxidant capacity (AC) as deodorant
mass increased. This corresponded to an increase in vitamin E and chlorophyll
contents, associated with longer wavelengths in the fluorescence emission
spectrum. Correspondingly, increase in deodorant mass resulted in increase in
florescence intensity (FI) at longer wavelengths. The fresh cinnamon and the
lemongrass deodorant had 169 % and 78 % in AC respectively. There was
reduction 91 % in AC after exposure to sunlight protected and not protected
from UV, with the reduction of 91.4 % being greater for samples not
protected. FI peaks at longer wavelength of the samples decreased after
exposure to sunlight
