质构仪及流变仪研究k-卡拉胶的凝胶特性

Study on the Gelling Properties of k-Carrageenan with Textural Analyzer and Rheometer

本文研究了1.5%k-卡拉胶溶液(质量浓度)的粘度以及水凝胶与钾凝胶的凝胶特性,分别从凝胶强度、弹性模量及动态粘度等指标进行考察。同时,研究了卡拉胶自身含有的离子对粘度以及凝胶特性的影响。实验结果表明k-卡拉胶中K、Na、Ca、Mg含量存在差异性,这些元素含量,特别是K、Ca含量的高低影响卡拉胶溶液的粘度以及水凝胶的凝胶强度、弹性模量值、动态粘度值。水凝胶在凝胶强度测定中出现脆性,增加钾离子明显提高凝胶体的凝胶强度、弹性模量及动态粘度,形成的钾凝胶易析水收缩而未出现脆性。水凝胶耐剪切能力强于钾凝胶,流动时应变高于钾凝胶,应力亦相应低于钾凝胶。另外,水凝胶与钾凝胶的弹性模量基本不随频率增加而增加,而动态粘度却随频率出现明显的剪切稀化现象。

In this paper the viscosity of 1.5% k-Carrageenan solution（m/m）as well as the gelling properties of hydro-gel and potassium-gel were studied separately,investigated from the gelling strength,elastic modulus and dynamic viscosity etc. The influences of ion content contained in carrageenan on viscosity and gelling properties were studied. The experimental results showed that there existed the difference on K,Na,Ca and Mg content in k-Carrageenan,which would affect the viscosity of carrageenan solution and gelling strength,elastic modulus and dynamic viscosity of hydro-gel especially the content of K and Ca. In the determination of gelling strength of hydro-gel the brittleness occurred. The increase of potassium in the carrageenan solution would significantly improve the gelling strength,elastic modulus and dynamic viscosity of gel which were easy to show syneresis and not brittleness. The hydro-gel was more resistant to shear and the value of strain was higher than that of the potassium-gel on the occurrence of flow while the value of stress was lower than that of potassium-gel. In addition,the elastic modulus of the hydro-gel and potassium-gel was not increased with the increase of frequency,but the dynamic viscosity increased with the frequency showing the characterization of shear thinning.