Bioavailability of iron in fermented soybeans

A rat bioassay method based on hemoglobin depletion-repletion assay was used to assess the relative biological value (RBV) of iron (Fe) in different test diets containing fermented or non-fermented soybeans, in mixtures with casein, and corn oil in a glucose monohydrate matrix, that were either boiled or autoclaved. The Fe RBV was lowest (60%) in the boiled non-fermented soybean diet; however, the RBV level was increased by fermentation by lactic acid-producing microorganisms to 87% and by Rhizopus oligosporus fermentation to 88% (relative to ferrous sulfate as 100%), suggesting that such fermentation of soybeans increases Fe bioavailability.(wz)