Texture and rheological characterization of kappa and iota carrageenan in the presence of counter ions
Texture and rheological characterization of kappa and iota carrageenan in the presence of counter ions
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DOI：
10.1016/j.carbpol.2010.04.024
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发表时间：
2010-08
影响因子：
11.2
通讯作者：
T. Thrimawithana;S. Young;D. Dunstan;R. Alany
中科院分区：
文献类型：
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作者：
T. Thrimawithana;S. Young;D. Dunstan;R. Alany
分别采用质构仪、低温扫描电镜和振荡流变仪研究了阳离子浓度和离子价态（0 ~ 0.2%（w/v）KCl或CaCl 2·2 H2O）对κ（κ）和ι（ι）卡拉胶水分散体的力学、微观结构和流变性能的影响。探针渗透法表明，随着阳离子浓度的增加，卡拉胶系统的“硬度”降低，表现出初始最大值后。使用单轴压缩方法测定κ-卡拉胶凝胶的杨氏模量（E）。E是在相同实验条件下记录的剪切模量的约3倍;表明通过使用粗糙化的平行板来消除滑移。具有Ca 2+的1-卡拉胶凝胶的储能模量表现出与机械性质类似的趋势。然而，在储存的κ-卡拉胶系统中观察到的脱水收缩可能降低了探针渗透法的灵敏度。冷冻-SEM观察凝胶揭示了与所观察到的机械性能相一致的微观结构。
The effect of cation concentration and ion valency (0–0.2% (w/v) of KCl or CaCl2·2H2O) on the mechanical, micro-structural and rheological properties of aqueous kappa (κ) and iota (ι) carrageenan dispersions were investigated using a texture analyzer, cryo-SEM and an oscillatory rheometer, respectively. The probe penetration method demonstrated a decrease in “hardness” of carrageenan systems with increasing cation concentration, after exhibiting an initial maximum. The Young's modulus (E) of κ-carrageenan gels was determined using the uniaxial compression method. E was approximately 3 times the shear modulus recorded under the same experimental conditions; indicating the elimination of slip by the use of roughened parallel plates. The storage modulus of ι-carrageenan gels with Ca2+demonstrated a similar trend to mechanical properties. However the syneresis observed in κ-carrageenan systems with storage, may have reduced the sensitivity of probe penetration method. Cryo-SEM observation of gels revealed a microstructure consistent with the observed mechanical properties.