Disclosed is a process of producing a soy protein product having a protein content of at least 60 wt% (N x 6.25 ) on a dry weight basis, which includes: (a) extracting a soy protein source with an aqueous calcium salt solution at a pH of 4.5 to 11 to cause solubilisation of soy protein from the soy protein source and to form a mixture of aqueous soy protein solution and residual soy protein source (b) optionally diluting the mixture of aqueous soy protein solution and residual soy protein source, (c) adjusting the pH of the mixture of aqueous soy protein solution and residual soy protein source to a pH of 1.5 to 4.4, (d) separating the acidified aqueous soy protein solution from the residual soy protein source, (e) optionally concentrating the acidified aqueous soy protein solution while maintaining the ionic strength substantially constant using a selective membrane technique, (f) optionally diafiltering the optionally concentrated soy protein solution, and (g) optionally drying the optionally diafiltered and optionally concentrated soy protein solution.
