Effect of salts on soy storage proteins defatted with supercritical CO2 and alcohols

The primary objective was to determine whether salts will stabilize soy storage proteins against the denaturing effects of alcohols or the heat and pressure used in supercritical CO2 during the defatting process. Nitrogen solubility index (NSI) and differential scanning calorimetry (DSC) were used to monitor the denaturation of proteins. A variety of salt solutions used to hydrate full‐fat soy grits increased the thermal stability of both 7S and 11S storage proteins. DSC was used to monitor their denaturation temperature. Neutral salt hydrations followed the lyotropic series for protein stabilization. Of the salts evaluated, the test results indicate that the reducing salt, sodium sulfite, and the neutral salt, sodium sulfate, when used to steep beans, yielded significantly higher NSI than did the water‐steeped controls or other salt treatments after partial defatting with absolute isopropanol or ethanol and supercritical CO2. However, these same salt treatments did not as effectively stabilize the proteins against the denaturing effects of ethanol more aqueous than 84% when these alcohols were used as the defatting medium.