Elevated Iron Levels in Machine-Grinded Cassava (Manihot esculenta, Euphorbiaceae) in Iwo, Southwest Nigeria as Determined by Atomic Absorption Spectrometry

Abstract

The potential of trace amounts of elements to contaminate food during processing in some local communities of Nigeria has since been a subject of concern. In Iwo, South West Nigeria, the processing method of converting the highly perishable cassava tubers to more stable products such as the roasted granular product, Gari involves grating/grinding of peeled cassava tubers and this process is suspected to introduce trace elements into the final product. This study determined and compared the levels of trace elements in peeled and machine-grinded cassava tuber samples. Peeled cassava tuber samples and machine-grinded cassava tuber samples were collected, prepared by acid digestion and filtration. Elemental analysis was carried out using PG-990 Atomic Absorption Spectrophotometer in the flame configuration mode. Iron (9.500 ± 0.025 mg/kg), Copper (11.200 ± 0.025 mg/kg) and Magnesium (251.317 ± 0.038 mg/kg) were present in the peeled cassava tubers; while for the machine-grinded cassava tubers, Iron (63.075 ± 0.025 mg/kg), Copper (11.650 ± 0.025 mg/kg), Magnesium (250.500 ± 0.250 mg/kg) and Manganese (0.650 ± 0.025 mg/kg) in addition were present. Comparison of these results revealed that Iron concentrations for machine-grinded cassava tubers were significantly higher than peeled cassava tubers (p < 0.05). This result suggests that the grinding process during cassava preparation might have introduced Iron, a trace element contaminant to the product (Gari). This report reveal that the appropriate health authorities and regulatory agencies need to set limits with a view of safeguarding consumers’ health.