A bread wheat zinc biofortification project - Assessment of low-technology processing methods to reduce the phytate content of cereals

Improving the nutritional quality of food crops and animal feedstuffs involves not only increasing the concentration of minerals through breeding and fertilization initiatives (biofortification) but also improving their bioavailability, since only 5-15% of the mineral content in unprocessed seeds is metabolized by humans or animals. The main reasons for this low bioavailability are the cell compartmentalisation and the natural occurrence of absorption inhibitors (such as phytate and phenolic compounds). Processing techniques can be improved in order to maximize the bioavailability of minerals, but the fortified crop and food must be supervised in order to avoid mineral contaminants. In developing countries, the major part of the population lives in rural areas and the access to centrally processed food is quite limited. As a result, home-based strategies to reduce antinutritional factors, such as phytate and phenolic compounds, may be the most feasible methods to improve mineral bioavailability. In this work, several methods of decreasing the phytate content of cereals with relatively low technological requirements are reviewed and compared in Zn biofortified wheat genotypes (to be selected after a thorough biochemical and physiological evaluation). These methods include fermentation, germination and soaking. Products will be compared in terms of nutritional, dietary bulk and acceptability criteria. Soaking may be a more effective method at the household level as the dependent factors are non-biological, easier to control and culturally more acceptable. But removal of other water soluble nutrients (such as vitamins) should be further elucidated.