Abstract:
Physiochemical properties of oils depend on the quality of the raw material
and the extraction method. White coconut oil (WCO) and virgin coconut oil (VCO)
which are extracted by different extraction methods are widely used in Sri Lankan
cuisine and in folk medicine. The study aimed to determine the physiochemical prop-
erties of WCO and VCO and to evaluate the effects of extraction methods on the
quality of coconut oils. Mature coconuts of the ‘Tall’ cultivar from plantations in
North-West were used in oil extraction. Unrefined VCO and WCO were extracted
from fresh coconut kernel and copra, respectively using small-scale oil expellers.
Fatty acid profiles, colour, refractive index (RI), relative density (RD), free fatty acid
content (FFA), moisture, and peroxide values (PV) were determined according to the
Sri Lankan Standards 313: Methods for analysis of vegetable fats and oils. Statistical
analysis was performed using 2- sample t-test. The extraction method had a signifi-
cant influence on the physiochemical properties of WCO and VCO. The fatty acid
composition of WCO and VCO were similar (P>0.05). White coconut oil had a higher
colour index than VCO (9.67±2.82 vs. 0.77±0.23, P<0.01), probably due to extraction
of copra with the testa intact. Free fatty acid content, PV and moisture content were
higher in WCO when compared to VCO (0.39±0.12 vs. 0.08±0.02, 0.19±0.01 vs.
0.00±0.00, 0.13±0.02 vs. 0.06±0.01), respectively (P<0.05). Results indicated a lower
oxidative stability, increased acidity and initiation of oxidation in WCO. The low
moisture content of VCO indicated a longer shelf life and the potential to naturally
preserve. No significant differences were observed between RI and RD. All values of
both oils except the colour index of WCO complied with SLS standards. In conclu-
sion, based on physiochemical properties, VCO is superior in quality to WCO. Co-
conut being a main agricultural produce of Sri Lanka, promotion of more beneficial
and productive practices in processing of coconut for human nutrition is emphasized.
