PURPOSE: To perpare soybean or soybean protein having improved quality, free from soybean smell and unagreeable odor and taste, by extracting soybean or soybean protein with a liquid obtained by the alkali- and active carbon-treatment of an alcohol-containing solvent used in extraction process.

CONSTITUTION: Soybean or soybean protein is extracted with an alcohol-containing solvent to improve the quality of the soybean or the soybean protein. The circulation ethanol containing the components having unagreeable taste and odor is introduced through the line 1 into the thermal reactor 3, and an alkali is introduced through the line 2 into the reactor in the form of an aqueous solution. The amount of the alkali is ≥0.1wt% based on ethanol. The mixture of the ethanol and alkali is mixed under heating at 40W82°C to react a part of the ill-odor component with the alkali. After the completion of the reaction, the reaction solution is transferred to the concentrator 4, and distilled under atmospheric or reduced pressure. The concentrated residue is discharged from the outlet 5, and the ethanol vapor is condensed in the condenser 6. The condensed ethanol is passed through the active carbon adsorption column 7 to remove the remaining ill-odor component completely.