To investigate the effect of different Ethiopian soil types on the total iron content of cereals and investigate the potential bioaccessibility of the extrinsic and intrinsic iron
Two separate analysis were conducted, one for cereals (red teff, white teff, white wheat and white sorghum) and the other for the soil types (andisol, cambisol, nitisol and vertisol) To determine the total iron content and iron fractions (exchangeable, carbonate bound, oxide bound, organic bound and residual) fractions by using sequential extraction procedures.
The study result showed that the total iron content of the four soil types were significantly different (p<0.05) and clay rich nitisol had high amount of iron content (6972.63± 25.56 mg/100g DM). Alkaline soil andisol had low amount of iron content (3163.36± 22.33 mg/100g DM). Vertisol had total iron content of 4483.4± 52.93 mg/100g DM and cambisol had total iron content of 6390.49± 47.84 mg/100g DM. The iron content of non-contaminated cereals were significantly different (p<0.05) except red teff (6.48± 0.19 mg/100g DM) with white teff (6.52± 0.2 mg/100g DM). The iron content of white sorghum was lower (4.04± 0.13 mg/100g DM) followed by white wheat (4.49± 0.13 mg/100g DM). Very small amount of iron from cambisol (0.001%) and vertisol (0.004%) had potential bioaccessibility but not in nitisol and andisol when analyzed alone. Intentional contamination of white teff (50%) with equal amounts of the four soil types had highest exchangeable fraction than the non-contaminated one (increased by 2.6%) from the total iron in case of cambisol contamination and (increased by 0.3%) in case of nitisol contamination. A significant difference was observed on the fractionation profile of soils and cereals (p<0.05).
Soil type variation had an impact on the potential bioaccessibility of cereals and soil with cereal combination had better bioaccessibiliy potential than cereals alone.