Effect of Grinding Plates (GUK, Parpela and Premier) on Maize Flour Milled within Samaru, Nigeria

This research work was carried out to determine the concentration of Cu, Mn, Pb and Fe in maize flour milled by different types of milling plates in Samaru, Zaria, Nigeria. Three different types of milling plates with the trade names GUK (Gibraltar upgrade kit), Parpela and Premier were identified at different locations where the dry maize grains bought from Samaru market were milled three times to obtain a smooth texture. Sample of the maize was also ground using porcelain mortar and pestle to serve as control. Wet digestion was carried out on the flour samples and the concentration of Cu, Mn, Pb and Fe determined using atomic absorption spectroscopy. The results showed that the concentrations of the metals were higher than those of the control. Using one-way ANOVA, there was a significant difference (P < 0.05) between the metal levels in maize flour milled with grinding plate and those ground with mortar and pestle. This implies that the grinding plates have contributed significantly to the heavy metals in the maize flour. Pb and Mn levels from the three milling plates were higher than the recommended limit set by the FAO/WHO, but the Pb level from Premier plate which is foreign was much higher than others which are locally fabricated. This could be undoubtedly injurious to the human body. Therefore, the quality of the grinding plates imported or fabricated locally in Nigeria should be checked by the relevant agency such as Standard Organisation of Nigeria (SON).