Multielement analysis of wheat flour: comparison of conventionally and organically grown crops

There has been an increasing consumer interest in organically produced food due to concerns regarding use of pesticides in farming and general efforts to use more environmentally compatible production methods. Although food products from organic origin are believed to be more nutritious than conventional foods, clear experimental evidence supporting this assumption is still lacking. Considering the high worldwide average consumption of cereal products, these foodstuffs have received considerable attention because of their potential role as vehicles of major and trace elements in the human diet, both essential and toxic ones. Analysis of these elements in flours is therefore important from nutritional and toxicological point of view. In this work we examined possible influence of conventional and organic agricultural practice on the content of major and trace elements in wheat flour. An optimized and validated ICP-MS method was used for multielement analysis of microwave digested wheat flour samples obtained from eight wheat cultivars. The mass fractions of major elements Ca, Mg, K and trace elements Al, As, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr, V, Zn were measured. The accuracy of the method was evaluated by analysing certified reference materials IAEA H-9 (mixed human diet) and NIST 1567a (wheat flour). The recoveries were within the range 85-115%. Statistically significant differences between conventional and organic wheat flour samples were found for Mg, As, Cd, Cr, Cu, Fe, Mn, Mo and V.