Electrodialysis (ED), bipolar-membrane electro-acidification (BMEA), and a combination of ED followed by BMEA (ED+BMEA) were evaluated for magnesium (Mg) and protein recovery and electrical energy consumption when processing soy tofu whey that was manufactured using magnesium chloride as a protein coagulant. ED processing for 30 min and BMEA processing for 60 min recovered 18.4% and 14.3% of the soy tofu whey Mg respectively. BMEA processing for 60 min recovered 22.7% of the soy tofu whey protein. The combination of ED processing for 60 min followed by BMEA for 60 min recovered 65% and 34.7% of the soy tofu whey Mg and protein, respectively.