Tesfaye and Abebaw 2016 - Essential metals in edible oils from Ethiopia

Tesfaye and Abebaw measured physico-chemical quality parameters and selected essential metals in four edible oil samples from the Ethiopian market. The metals table reports Cu, Zn, and Fe concentrations in mg/L after wet digestion and FAAS, with Na and K measured by flame photometry. This is not a toxic-metal occurrence paper for Pb, Cd, arsenic, or mercury, but it provides primary oil-matrix concentration data for copper, zinc, and iron in imported palm oil and Ethiopian nuog/niger seed oil.

Key numbers

Essential metals in edible oils

Table 5 reports mean +/- SD in mg/L. The original table uses commercial sample names; this source page relabels them by oil category and sample number to preserve the brand firewall.

The source states that the calibration curves for Na, K, Cu, Zn, and Fe had correlation coefficients from 0.9977 to 0.9999. Method detection limits were Na 0.0306 mg/L, K 0.0191 mg/L, Cu 0.0246 mg/L, Zn 0.0151 mg/L, and Fe 0.0283 mg/L. Limits of quantitation were Na 0.306 mg/L, K 0.191 mg/L, Cu 0.246 mg/L, Zn 0.033 mg/L, and Fe 0.075 mg/L.

Physico-chemical quality parameters

Table 1 reports mean +/- SD for four oil samples:

The authors state that all acid values and peroxide values were within the FAO/WHO comparators they used, while the saponification value for one niger-seed-oil sample and the iodine value for one imported palm-oil sample and one niger-seed-oil sample were outside their cited comparator ranges.

Methods (brief)

The study selected two imported palm-oil samples and two Ethiopian processed nuog/niger-seed-oil samples from the Merkato commercial center. For metal analysis, triplicate 1 g oil samples were digested with concentrated nitric acid/hydrogen peroxide (2:1 v/v) plus sulfuric acid on a Kjeldahl digestion furnace at 250 C until clear. The solution was evaporated, redissolved in 0.2 M nitric acid, filtered, diluted to 50 mL, and analyzed for Cu, Zn, and Fe by flame atomic absorption spectroscopy. Sodium and potassium were measured by flame photometer.

The metal values are reported in mg/L in the diluted oil digest solution. The source does not report Pb, Cd, arsenic, mercury, nickel, aluminum, chromium, or tin.

Implications

Certification: This source is not a primary source for the HMTc toxic-metal analytes, but it provides edible-oil matrix context for Cu, Zn, and Fe in Ethiopia-market palm oil and niger seed oil. Do not use it as evidence of absence for Pb, Cd, arsenic, or mercury.

Courses: Useful for showing the difference between oil quality parameters and contaminant occurrence: the paper combines acid, peroxide, iodine, and saponification values with essential-metal measurements.

App: Adds category-level essential-metal context for palm oil and niger seed oil. Brand names from the source should remain excluded.

Microbiome: Not addressed.

Wiki pages this source may touch

• copper
• zinc
• iron
• palm-oil
• niger-seed-oil
• vegetable-oil
• vegetable-oils
• cooking-oils-other

Verification notes

• PDF title page identifies the article as Advances in Chemistry, Volume 2016, Article ID 3480329, 7 pages, with DOI 10.1155/2016/3480329.
• The PDF states that the article is open access under the Creative Commons Attribution License.
• The source names four commercial oil samples; this page omits those brand names and assigns category-level labels.
• The abstract reports Cu and Zn values as “mg”, while Table 5 labels the concentration columns as mg/L. This page follows Table 5 and treats mg/L as the source-reported unit.
• sample_n: 4 counts the four market oil samples; the analytical measurements were performed in triplicate.
• Provisional ingredient scaffolds were created for palm-oil and niger-seed-oil because neither exact ingredient slug existed before this ingest.

Page history

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