Liyansan, Segun Michael, Fatunsin, Oluwatoyin Tirenioluwa, Olayinka, Kehinde Ololade

Keywords: Palm oil, physicochemical, limit, adulteration, food quality

Abstract

Background: The evaluation of the physicochemical properties of palm oil is a reliable means of ascertaining its quality and suitability for certain applications. Aim: This study was therefore carried out to examine the physicochemical parameters of sixty (60) unbranded palm oil samples collected from major markets in Lagos, Nigeria. Method: Nine physicochemical parameters such as viscosity, specific gravity, moisture content, refractive index, impurity level, acid value, iodine value, peroxide value and saponification value were analyzed in this study employing standard laboratory methods. Results: The results obtained from the properties analyzed for all the samples had the following ranges: Moisture contents (0.199 ± 0.19 %- 6.209 ± 3.83 %), specific gravities (0.91 ± 0.004 – 0.916 ± 0.002), refractive indices (1.46 ± 2.34E-16 0Bx- 1.454 ± 0.019 0Bx), viscosities (23.536 ± 15.37 cP- 672.486 ± 1836.06 cP), impurity levels (0.145 ± 0.06 %- 15.618 ± 4.39 %), acid values (3.6634 ± 0.950 %- 5.4471 ± 2.80 %), iodine values (45.533 ± 1.79 Wijs- 98.974 ± 22.50 Wijs), free fatty acid value (1.8317± 0.48 %- 2.72355± 1.40 %), peroxide values (1.968 ± 2.81 meq/kg- 17.826 ± 17.09 meq/kg) and saponification values (121.483 ± 44.56 mg KOH/g- 200.559 ± 9.82 mg KOH/g). P-value of 0.74237 obtained for all the parameters were more than the traditional p-value of 0.05 showing that there is no notable difference between the values of the physicochemical parameters of all the palm oil samples. The refractive index and specific gravity values for all the samples agrees the Standard Organization of Nigeria (SON) limit. However, the other parameters analyzed exceeded the standard set by SON and was associated with the primitive processing techniques, poor storage practice, the usage of bad palm fruits, climatic and soil conditions. Conclusion: There should therefore be adequate sensitization of palm oil traders and manufacturers along with enforcement to ensure best practices are employed during processing, transportation, and storage of the palm oil products.