Overview
This study compared crude and refined soybean oil from two factories in Benue State, Nigeria, for physicochemical quality, aflatoxins, solvent residues and six metals by AAS. Cadmium, arsenic and lead were found only in the crude oils and were not detected after refining.
Key numbers
- Crude oil, factory A and B: cadmium “0.82±0.01” and “0.86±0.01” mg/kg; arsenic “0.46±0.01” and “0.50±0.01” mg/kg; lead “0.08±0.01” and “0.09±0.01” mg/kg (Table 2, p. 11).
- Refined oils: cadmium, arsenic and lead “ND”; nickel “0.01±0.01” mg/kg (Table 2).
Methods (brief)
Oils bought at the factories were analyzed by AAS following AOAC methods; the digestion step is not described. Results are means of triplicate determinations on one sample per oil. No detection limits, reference materials or recoveries are reported, and the wavelength list omits cadmium.
Evidence Fitness
Four samples from two producers, with weak QA and no stated detection limits, so the “ND” values are uncensored-unknown. The discussion gives lead and iron in mg/g while the table uses mg/kg; the table units are used. Soybean oil is a vegetable oil ingredient proxy for italian-dressing and for rice-bran-oil (no dressing or rice bran oil was measured), so those pages are not linked.