MTGase聚合的酪蛋白酸钠生物聚合物的物化性质

Physicochemical Properties of MTGase-induced Biopolymers of Sodium Caseinate

研究了微生物转谷氨酰胺酶 (MTGase)对酪蛋白酸钠 (SC)的聚合作用 ,以及相应形成的生物聚合物的一些物化性质 ,包括分子质量范围、粘度及热稳定性等 .SDS PAGE和GPC分析显示 ,SC经MTGase聚合后 ,生成分子质量更高的生物聚合物 .MTGase的催化时间不同 ,生成的生物聚合物分子质量及其分布也有所不同 .布拉班德粘度计分析显示 ,在相同蛋白质量分数下 ,经MTGase聚合形成的SC -生物聚合物溶液的表观粘度显著高于SC溶液的表观粘度 (达 2～ 4倍 ) .加热处理实验显示 ,SC -生物聚合物溶液的热稳定性显著高于未经聚合的SC溶液 ,而DSC分析则显示不同温度下MTGase聚合形成的SC -生物聚合物的耐热性能有所不同 ,更高温度 (5 0℃ )下形成的生物聚合物的耐热性能更强 (与 37℃相比 ) .

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 is 2～4 times that of SC solution with the same protein mass fraction. Heat-treatment 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 at 37℃.