Effect of Aqueous-alcohol Leached Soybean Protein Concentrate on Dough and Its Protein Properties

To investigate the effect of aqueous-alcohol leached soybean protein concentrate (SPC) addition (0%~8%) on dough and its protein properties, the gluten properties, tensile properties and dynamic rheological properties, protein components, disulfide bonds, and microstructure of dough were studied, and soybean protein isolate (SPI) was used as control. The results showed that with the increase of SPC addition, the wet gluten content and the resistance to extension of dough increased significantly (P<0.05), and the gluten index and the extensibility decreased significantly (P<0.05). Addition of SPC could improve the storage modulus (G') and loss modulus (G'') of dough, and the dough with 8% SPC exhibited a lowest loss tangent (tanδ) which indicated the prominent elasticity of the dough. The addition of SPC increased the relative contents of SDS-soluble proteins and decreased alcohol-soluble proteins and glutenin macropolymers significantly (P<0.05). Furthermore, it promoted the formation of new disulfide bonds in the dough. Image of the confocal laser scanning microscopy demonstrated that SPC disrupted the gluten network. In conclusion, SPC linked with glutenin by disulfide bonds to form small aggregates which induced the change of protein composition and gluten network structure and subsequently modified the dough properties, and significant differences in dough properties were observed with different SPC addition levels.