The objective was to analyze the emulsifying capacity of different soybean wheys as integral products. The following samples were tested: lyophilized soybean whey (LSW), heated LSW (HLSW), lyophilized tofu whey (LTW) and heat-dried tofu whey (HDTW). The emulsions were carried out at same level of total protein (0.1–1.0% w/v, phosphate buffer 10 mm, Φw=0.33, Ul- traturrax T-25). Emulsion stability (measured by the separated oil) decreased in the order: HLSW> HDTW> LTW> LSW. These results are correlated with emulsifying activity index (EAI) with and without SDS. Assays of backscattering and laser diffraction showed a reduction of particle size in emulsions prepared with heated whey (HLSW and HDTW in comparison with LSW and LTW, respectively). The differences between HLSW and TDTW can be attributed to the glycosilated products generated during thermal treatment under anhydrous conditions, factors which prevent the flock formation postulated as the main mechanism to destabilize these emulsions.