摘要
配制总质量分数为1%的CMC与瓜尔胶的复配溶液,两者质量分数比例分别为0.1%∶0.9%,0.2%∶0.8%,0.3%∶0.7%,0.4%∶0.6%,0.5%∶0.5%,0.6%∶0.4%,0.7%∶0.3%,0.8%∶0.2%,0.9%∶0.1%。通过稳态流动、应变扫描、频率扫描及动态粘弹性温度扫描与动态黏度温度扫描,观察复配溶液的黏度特性随剪切速率与温度的变化,粘弹性随不同应变、不同频率与温度变化,以及考察模量频率相交点、松驰时间及构象转变温度等与结构特性相关的各因素。试验结果表明：CMC与瓜尔胶之间存在明显的协同增效作用,两者复配有利于增加零剪切黏度、黏度及粘性模量与弹性模量。复配比例改变溶液的粘弹性质,当瓜尔胶的比例达到0.4%后溶液的模量频率相交点均低于单一的瓜尔胶溶液,而松驰时间却比后者高。复配溶液改变了动态粘弹性温度扫描时的凝胶点温度,其均高于单一瓜尔胶溶液的凝胶点温度。根据动态黏度温度扫描结果,复配溶液中CMC的加入改变了瓜尔胶溶液的粘温特性,当瓜尔胶的含量在0.1%~0.6%时出现明显的构象转变温度。
On a basis of total concentration 1% with CMC and guar gum a series of complex solutions are prepared, where the ratio between them are 0.1% ∶ 0.9%, 0.2% ∶ 0.8%, 0.3% ∶ 0.7%, 0.4% ∶ 0.6%, 0.5% ∶ 0.5%, 0.6% ∶ 0.4%, 0.7% ∶ 0.3%, 0.8% ∶ 0.2%, 0.9% ∶ 0.1% respectively. Through the experiments like steady flow, strain sweep, frequency sweep, dynamic visco-elasticity and viscosity temperature sweep, we observe the viscosity characteristic of the mixed solution varies with shear rate and temperature, the visco-elasticity varies with oscillation strain, frequency and temperature, also investigate several factors like cross-point of modulus and the relaxation time in frequency sweep and the conformational transition temperature etc. associated with the structural characteristics as the proportion of mixed solution changes. The results show that there exists obvious synergies between CMC and guar gum, and the complex of them helps to increase the zero-shearing viscosity, viscosity, viscous modulus and elastic modulus. The complex proportion changes the visco-elastic properties of solution, and after ratio of guar reaches 0.4% and above the cross-point of modulus are all below than a single guar solution, while the relaxation time higher than the latter in the experiments of frequency sweep. Similarly, the gelling temperature when G′=G″ in the experiments of dynamic visco-elasticity temperature sweep are also changed, which are all higher than a single guar solution. According to the dynamic viscosity temperature sweep, the addition of CMC in mixed solution changes the viscosity-temperature characteristics and when the ratio of guar is in range from 0.1% to 0.6% the significant conformational transition temperature are observed.
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2014年第2期118-126,共9页
Journal of Chinese Institute Of Food Science and Technology
基金
2011年浙江省公益性技术应用研究(分析测试)项目(No.2011C37023)
