Abstract:

Rheological property of konjac oligo-glucomannan（KOGM）with various molecular weights in the presence of alkali（sodium carbonate）was studied by dynamic viscoelastic measurements. Molecular weight and other molecular parameters of KOGM were determined by SEC-MALS. The results show that radius of gyration（R_g）decreases and the relative stiffness parameter（β）increases from 0.38 to 0.80 with the decrease of molecular weight（M_w），which means KOGM chains become short and stiff. The storage shear modulus G' and the loss shear modulus G'' increase and loss factor tand decrease with the increasing of KOGM M_w，KOGM concentration and alkali concentration，which indicates that the gels get more elastic and stable.

摘要：

探讨了碱存在下不同分子量魔芋葡甘露低聚糖（KOGM）的流变特性。采用高级旋转流变仪和凝胶渗透色谱-静态光散射联用仪（SEC-MALS）测定魔芋葡甘露低聚糖的分子量、相关分子参数和流变性质。SEC-MALS分析结果表明，随KOGM分子量的下降，均方根旋转半径迅速减小，相对刚性参数β从0.38增加到0.80，即分子链由半柔顺性链向短小的刚性链转变。流变分析结果表明，所形成凝胶的储能模量G'和耗能模量G''均随着KOGM相对分子量、KOGM浓度和碱浓度的增加而增加，损耗因子tand 则相应减少，即形成凝胶的弹性和稳定性增加。