一株融合菌株G23产胞外多糖的流变学特性

Rheological properties of the exopolysaccharide produced by fusion strains G23

融合菌株G23是由植物乳杆菌C88和发酵乳杆菌F6通过原生质体融合获得的菌株。采用动态流变仪,在不同多糖质量浓度、温度、pH值条件下测定融合菌株G23所产生的胞外多糖的流变学性质。所产胞外多糖溶液是典型的非牛顿流体,胞外多糖质量浓度的增大可提高溶液体系的黏度。在10～80℃的较大温度范围内黏度变化较小,在所测温度范围内溶液黏度基本保持不变。在不同pH值条件下,胞外多糖溶液均表现为剪切力作用下黏度迅速下降趋势。胞外多糖加入脱脂乳溶液中能够明显的增加脱脂乳的黏度,且溶液的黏度下降变慢。在试验的频率范围内,随着胞外多糖溶液质量浓度的增加,对应的交叉频率的值相应变大,胶体特征越明显。

Fusion strain G23 was obtained by protoplast fusion of Lactobadllus plantarum C88 and Lactobacillusfermentum F6. The solution rheology of exopolysaccharide produced by fusion of strain G23 was measured by dynamic rheometer at different polysaccharide concentration, temperature, pH values. The exopolysaccharide solution is a typical non-Newtonian fluid. The increasing the concentration of extracellular polysaccharides can improve the viscosity of aqueous solution. The viscosity of extracellular polysaccharide solution produced by fusion mutants G23 had httle change at the range of 10-80℃, the extracellular polysaccharide display a thermal stability properties in the measured tempera- ture range. And the viscosity of the extracellular polysaccharide solution remained unchanged with the shearing time extension. In different pH values, the extracellular polysaccharide solution showed the rapid decline when the shear rate increased. The skim milk solution by adding exopolysaccharide can significantly increase the viscosity, and with the shear rate increases, the decrease rate of viscosity of skim milk added exopolysaccharide became slow. In the measured frequency range, with the increasing concentration of exopolysaccharide increased the corresponding value of the crossover frequency, which meant that the higher the concentration of exopolysaccharide solution showed the more obvious colloid features.