Assessment of home-based processing methods to reduce the phytate content and phytate/zinc molar ratio of white maize (Zea mays).
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Various methods of processing maize suitable for household use in rural Malawi, Central Africa, were investigated for their ability to reduce its phytate content and phytate/zinc molar ratio. These methods included fermentation, germination, and soaking. Penta- and hexainositol phosphates were measured by HPLC, and zinc was measured by atomic absorption spectrophotometry. Natural lactic fermentation of maize flour slurries resulted in 88% phytate retention compared to unprocessed, unrefined maize flour porridges, whereas lower phytate retention was observed when a starter culture (61%) or germinated flour (71%) was also used. Fermentation of cooked maize flour porridges with germinated flour added resulted in 54-85% retention of phytate compared to controls. Soaking maize flour or pounded maize and decanting excess water resulted in 43 and 49% retention of phytate, respectively. The latter soaking procedures were simple and effective and were suitable for household use in rural Malawian communities.