Abstract:

A novel method of preparing transparent cold-set hydrogels by soybean glycinin (11S）was developed.Addition of dextran sulphate (DS）to soybean glycinin (11S）in the first step induced the 11S/DS solution to form soluble complexes with higher negatively charged, which had a significant effect on improving transmittance after the preheat process.Cross-linking with microbial transglutaminase (MTGase）was used in the second step, and transparent gels were formed by ε-(γ-glutamyl）lysine isopeptide bonds at pH 7.0 with low ionic strength.The result indicated that transparency markedly increased at DS/11S (mass ratio）of 0.005 or more and decreased when NaCl was involved and much better hardness was achieved by covalent bond crosslinked with MTGase.Scanning electron microscopy showed finer and more intensive networks of gels were formed by addition of DS.Water holding capacity (WHC）increased when more DS was added.The combined effects of DS concentration and ionic strength influenced the rheological properties, and determined texture properties of gels.The inhibitory effect of DS would be ascribed to the formation of firmer and transparent soybean glycinin gels with better characteristics.