Physicochemical Properties, Heavy Metals and Aflatoxins Content of Crude Palm and Groundnut Oils Produced and Marketed in Benue State, Nigeria

Abstract

The study aims at assessing the physicochemical properties, heavy metals, and aflatoxins content of crude palm and groundnut oils produced and sold in the Adikpo, Wadata, and Otukpa areas of Benue state, Nigeria. Specific gravity, refractive index, acid value, saponification value, peroxide value, moisture content, and smoke point are the physicochemical properties evaluated. The heavy metals analyzed include; Lead, Nickel, Copper, Iron, Arsenic, and Iron. Total aflatoxins were determined by Enzyme-linked immunosorbent assay (ELISA).  Findings revealed that most of the physicochemical properties of palm and groundnut oils from these areas deviated from the Food and Agricultural Organization/World Health Organization (FAO/WHO) standard range. A high amount of Cadmium (0.89 mg/kg, 1.01 mg/kg, and 0.92 mg/kg) was detected in the local groundnut oil samples but lesser in palm oils from Adikpo, Wadata, and Otukpa respectively, while Copper content was within the FAO/WHO safe limits. The arsenic content of palm oil produced in the region was not as high as those in groundnut oil but was higher than the recommended maximum limit of 0.1 mg/kg. The Nickel content in the oil samples was higher than the 0.50 mg/kg permissible limit, but Lead was within the safe limits. Total Aflatoxin content in crude groundnut oil was within the range of 9.05 ppm to 10.13 ppm, while a range of 2.03 ppm to 2.74 ppm was recorded in crude palm oil. The locally produced oils are of lower quality, suggesting that refining should be adopted and quality seeds should be used for the extraction of oils.