LUNAM, Université du Maine, IMMM UMR CNRS 6283, PCI, 72085 Le Mans cedex 9, France.
LUNAM, Université du Maine, IMMM UMR CNRS 6283, PCI, 72085 Le Mans cedex 9, France.
Carbohydr Polym. 2014 Nov 4;112:10-5. doi: 10.1016/j.carbpol.2014.05.048. Epub 2014 May 27.
The effect of the addition of calcium or sodium ions on the potassium induced gelation of κ-carrageenan (κ-car) is investigated using oscillatory shear rheology and turbidimetry. Both the gelation kinetics and the steady state shear moduli are investigated. Gelation in mixed salt solutions is compared with that in pure potassium and calcium solutions. It is shown that the elastic shear modulus increases with increasing pure KCl concentration, but decreases with increasing pure CaCl2 concentration. In mixed salts, gelation of κ-car is induced by potassium and addition of CaCl2 leads to an increase of the elastic modulus with increasing CaCl2 concentration. κ-Car gelled at low mixed salt concentrations for which it remained liquid in pure salt. At equivalent ionic strengths, the effect of adding NaCl on potassium induced gelation is much weaker. In pure KCl solutions, κ-car gels are transparent, but in pure CaCl2 they become increasingly turbid with increasing CaCl2 concentration. The turbidity of gels formed in mixed salts is intermediate.
使用振荡剪切流变仪和浊度法研究了钙离子或钠离子的加入对κ-卡拉胶(κ-卡拉)的钾诱导凝胶化的影响。研究了凝胶化动力学和稳态剪切模量。将混合盐溶液中的凝胶化与纯钾和钙溶液中的凝胶化进行了比较。结果表明,弹性剪切模量随纯 KCl 浓度的增加而增加,但随纯 CaCl2 浓度的增加而降低。在混合盐中,κ-卡拉的凝胶化是由钾诱导的,加入 CaCl2 会导致弹性模量随 CaCl2 浓度的增加而增加。κ-卡拉在低混合盐浓度下凝胶化,而在纯盐中仍为液体。在等离子强度下,添加 NaCl 对钾诱导凝胶化的影响要弱得多。在纯 KCl 溶液中,κ-卡拉凝胶是透明的,但在纯 CaCl2 中,随着 CaCl2 浓度的增加,凝胶变得越来越浑浊。混合盐形成的凝胶的浊度处于中间状态。