Study on the gel properties and secondary structure of soybean protein isolate/egg white composite gels

Abstract

The gel properties and secondary structures of soybean protein isolate/egg white composite gels with different blend ratios and protein concentrations were investigated in this paper. The hardness, springiness and water-holding capacity of composite gels were all increased with the increase in the protein concentrations. When total protein concentration was above 0.03 g mL−1, the soybean protein isolate/egg white proteins blended in ratio of 1:1 showed higher enhancement in springiness and water-holding capacity. The hardness and storage modulus of gels increased gradually with the increase in egg white in the composite gels. The content of α-helical structures of the gels were increased firstly and then decreased, whereas the content of β-sheet was increased gradually with the increase in egg white ratio. The tendencies of α-helical and β-sheet were in accordance with springiness and hardness of gels, respectively. The microstructure investigations showed that gels formed an even structure with less large particles at the soybean protein isolate/egg white ratio of 1:1, which was related to the higher springiness and water-holding capacity. The relationship between changes in the protein structure and the texture properties could be used to design product systems.