Assessment of the Quality of Palm Oil Sold in Benue State, Nigeria
H. E. Otanwa *
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
F. G. Okibe
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
D. A. Itodo
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
E. Omale
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
F. H. Omotehinwa
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
J. Isa
Department of Chemistry, Federal University of Health Sciences Otukpo, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Palm oil is a critical dietary fat in Nigeria, yet growing evidence suggests extensive quality degradation and adulteration in local markets. This study assessed the physicochemical quality of palm oil sold in major Benue State markets (Makurdi, Otukpo, Benue Zone C) and compared it with oils obtained directly from rural production sources within Benue (Otukpa, Akpa, Edumoga, Igumale) and neighbouring states (Ankpa, Olamaboro, Ogoja). Thirty‑six samples were collected from twelve markets and seven source locations and analysed for moisture content, saponification value, peroxide value, iodine value, free fatty acid (FFA) content and specific gravity, benchmarked against Codex Alimentarius and Standards Organization of Nigeria specifications. Makurdi, particularly North Bank market, exhibited the most severe deterioration and likely adulteration, with moisture up to 0.91%, saponification values up to 239.95 mg KOH/g, peroxide values up to 17.84 meq/kg and FFA as high as 13.15%, all far exceeding recommended limits. Otukpo markets showed comparatively better quality, with moisture 0.29–0.50%, saponification 186.45–201.50 mg KOH/g, peroxide 5.70–11.05 meq/kg and FFA 2.71–5.00%, indicating reduced but still notable quality concerns. Benue Zone C samples had consistently low peroxide values (3.52–5.90 meq/kg) and generally acceptable FFA (2.30–7.35%), but several oils displayed markedly low iodine values (39.35–44.45 g I₂/100 g), strongly suggesting adulteration with highly saturated fats. In contrast, most source oils from Benue and non‑Benue locations showed saponification values within 190–209 mg KOH/g, peroxide values below 10 meq/kg, and FFA below or near the 5% limit for crude palm oil, implying that serious adulteration and oxidation occur primarily during distribution and retail rather than at production sites. These findings highlight significant public health risks from consumption of oxidised and adulterated palm oil in Benue markets and underscore the urgent need for strengthened regulatory surveillance, rapid field testing of key quality indices, certification and traceability systems, improved storage and handling practices, and consumer education to safeguard the palm oil value chain.
Keywords: Palm oil, adulteration, oxidation, peroxide value, public health risks