ABSTRACT The solubility of phytate and protein in soy extracts as influenced by pH, NaCl, calcium and EDTA was measured. The behavior of phytate is explained in terms of its binding to calcium‐magnesium and/or to proteins. Three processes for preparing low‐phytate soy protein products were derived from this theory, at both the laboratory and pilot plant scale. The nutritional properties of isolates prepared with these processes were examined.