不同分子量魔芋葡甘露低聚糖的流变特性

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tanδ则相应减少,即形成凝胶的弹性和稳定性增加。%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（Rg）decreases and the relative stiffness paramete（rβ）increases from 0.38 to 0.80 with the decrease of molecular weight（Mw）,which means KOGM chains become short and stiff.The storage shear modulus G＇ and the loss shear modulus G＇＇ increase and loss factor tanδ decrease with the increasing of KOGM Mw,KOGM concentration and alkali concentration,which indicates that the gels get more elastic and stable.