Structural characterization and physicochemical properties of protein extracted from soybean meal assisted by steam flash-explosion with dilute acid soaking

•Effect of SFE-acid soaking pretreatment on protein structure was studied.•The pretreatment changes the molecular weight distribution of SPI.•Acid soaking treatment only induced the loss of tertiary structure of SPI.•SFE treatment dramatically affected second structure of SPI.•The change of protein structure alters the physicochemical properties of protein.