Characterization of the Chemical Properties of Some Selected Refined Vegetable Oils Commonly Sold in Nigeria

Aims: To ascertain the suitability for consumption of some selected refined vegetable oils commonly found and sold in most of the markets located in Nigeria.
Study Design: Five different brands of vegetable oils commonly sold in Nigeria market, namely; Grand ground nut oil obtained from groundnut seed, turkey refined palm olein oil obtained from palm fruit, gino refined palm olein oil obtained from palm fruit, ideal refined palm kernel oil obtained from palm kernel seed and baron refined palm kernel oil obtained from palm kernel seed were subjected to Chemical analysis via determination of iodine value, acid value, peroxide value, saponification value and ester value of these oils.
Place and Duration of Study: The chemical analysis was carried out in the Chemistry laboratory of the National Open University of Nigeria suited on Ahmadu Bello Way, Victoria Island, Lagos State between May – June, 2014.
Methodology: The iodine value, acid value, Peroxide value and saponifcation value were determined by standard procedures described by AOAC (1980) while the ester value was determined by baltes, 1964 method.
Results: The analysed chemical parameters shows that the iodine value of the oils are in the range of 21.83 g/100g to 79.95 g/100g, while the Saponification values of the oils are in the range of 235.62 mg/kOH/g to 274.19mg. The acid values and peroxide values of the oils are in the range of 0.39 mgKOH/g to 1.54 mgKOHg and 0.26 meq/kg – 1.17 meq/kg respectively while the ester value range from 206.70 mgKOH/g to 272.65 mgKOH/g.
Conclusion: The result of the study shows that the oils are non drying oils of low saturation, slow to oxidation and rancidity, will remain liquid for a long time and are suitable for consumption.