Characterization and comparative analysis of metallic inclusions in dry, paste and wet ground maize (zea mays) forms and its health implication on human

T. O. Daniel, D. Azaki, C.N. Nwosu, A.O. Olaoye, G.E. Sule


This study investigates metallic inclusions in ground maize forms of dry, paste and wet using domestic grinding machine and its health implications to human. With progressive maize processing using the grinding machine, metals are introduced as contaminants into ground maize due to wear and tear of the grinding discs and other machine parts. Maize samples of 1 kg each were grinded in wet, paste, and dry forms. The metallic inclusions were extracted from the ground maize forms using magnetisation, sedimentation and decantation. The extractions were quantified using an Electronic weighing balance and were characterised using, Scanning Electron Microscopy, Optical Emission Microscopy and Energy Dispersive Spectroscopy. Iron fillings were discovered to be the dominant metallic inclusion present in the various food forms and also in the grinding disc with 88.48% by weight in the grinding disc. The extracted metallic inclusions is 0.157g/kg, 0.196g/kg and 0.268 g/kg for dry, paste and wet ground maize forms which exceeded the World Health Organisation limit of 15 mg/kg. The EDS result show that the wet form has the highest amount of metallic inclusions of 95.97 at. %, the paste form with 91.39 at. % and dry form with 83.35 at. %. From the SEM analysis of particle size, the dry, paste and wet ground maize had 17μm, 27μm and 36μm particle sizes respectively. When in excess the Iron filling metallic inclusions from the ground maize accumulates in body organs since there is no physiological mechanism to eliminate excess iron thereby leading to health complications. The accumulated iron in the heart causes increased risk of cardiovascular diseases, siderosis and hemochromatosis in the liver leading to hepatoma-the primary cause of cancer of the liver among others. Elevated levels of free iron also predisposed individuals to high risk of bacterial and viral infections leading to death.


Maize, Metal inclusion; Iron fillings; Scanning electron microscopy (SEM); Energy dispersive spectroscopy (EDS); Optical emission spectrometer (OES); Health implication.

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