Abstract:  The polymerization process of sodium caseinates （SC） induced by microbial transglutaminse （MTGase）and some physicochemical properties of the new-forming biopolymers such as the relative molecular mass‚the viscosity and the heat stability were investigated．SDS-PAGE and GPC analyses showed that biopolymers with higher molecular mass can be produced after the polymerization of SC induced by MTGase．The relative molecular masses and their distributions of the biopolymers change with the incubation time with MTGase．Brabender analysis shows that the apparent viscosity of SC-biopolymer solution is2～4times that of SC solution with the same protein mass fraction．Heat -treat -ment experiment shows that the heat stability of SC-biopolymer solution is markedly higher than that of SC solution．DSC analysis indicates that the heat resistance of SC-biopolymers polymerized at different temperatures is variable‚and better heat resistance will be obtained at a highter temperature （50℃） rather than at37℃．

Key words:  sodium caseinate, microbial transglutaminase, biopolymer, physicochemical property