LAUSR

BACKGROUND Traditional soy protein gel products such as tofu, formed from calcium sulfate or magnesium chloride, have poor textural properties and water retention capacity. Soy glycinin (SG) is the main component affecting the gelation of soy protein and can be cross-linked with polysaccharides, such as sugar beet pectin (SBP), and can be modified by changing system factors (e.g., pH) to improve the gel's properties. SG/SBP complex double network gels were prepared under weakly acidic conditions using laccase cross-linking and heat treatment. The structural changes of SG and the properties of complex gels were investigated. RESULTS SG exposed more hydrophobic groups and free sulfhydryl groups at pH 5.0. Under the action of laccase cross-linking, SBP could promote SG tertiary structure unfolding. The SG/SBP complex gels contain 46.77% β-fold content and had well-gelling properties of hardness 290.86 g, adhesiveness 26.87, springiness 96.70 mm at pH 5.0. The T22 relaxation time had the highest peak, and MRI showed that the gel had evenly water distribution. Scanning electron microscopy (SEM) and confocal scanning laser microscopy (CLSM) displayed that the SG/SBP complex network structure was uniform, and the pore walls were thicker and contained filamentous structures inside. CONCLUSION SG/SBP complex network gels have good water-holding, rheological and textural properties at pH 5.0. The properties of soy protein gels can be improved by binding to polysaccharides with laccase cross-linked and adjusting the pH of the solution. This article is protected by copyright. All rights reserved.