Formation kinetics and rheology of alginate fluid gels produced by in-situ calcium release
Formation kinetics and rheology of alginate fluid gels produced by in-situ calcium release
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DOI：
10.1016/j.foodhyd.2014.02.005
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发表时间：
2014-10-01
影响因子：
10.7
通讯作者：
Norton, I. T.
中科院分区：
文献类型：
--
作者：
Farres, I. Fernandez;Norton, I. T.
研究了使用原位钙释放和定义的剪切场产生的藻酸盐流体凝胶的形成和性质。结果表明，虽然在形成过程中颗粒生长速率在降低剪切速率时显着增加，但生成后颗粒间相互作用的速率不受剪切强度的影响。较长的聚合物链允许每条链有更多数量的可能的钙交联位点，这增强了渗透网络的形成并增加了流变有效的网络交联的数量。因此，高 M-w 海藻酸盐流体凝胶比低 M-w 海藻酸盐流体凝胶表现出更快的凝胶动力学和更大的粘度。颗粒硬度随着 CaCO3 浓度的增加而增加，直到达到临界值。静态凝胶显示出相同的 CaCO3 临界值，表明单个流体凝胶颗粒内的交联数量与其对应的静态凝胶相当。这是由于快速的线圈二聚体转变，在施加的剪切场下，导致动力学捕获的流体凝胶结构。然而，它们的结构响应与静态凝胶不同，这可能是由流体凝胶颗粒之间的桥接引起的。除了增进对藻酸盐生产流体凝胶的理解之外，这项工作还首次展示了如何通过选择藻酸盐分子量和 CaCO3 浓度来控制排序动力学和所得颗粒特性，从而有可能允许设计和交付具有所需属性的特定结构。 (C) 2014 Elsevier Ltd. 保留所有权利。
The formation and properties of alginate fluid gels produced using in-situ calcium release and a defined shear field are investigated.Results show that, while the rate of particle growth during formation increases significantly upon lowering the shear rate, the rate of inter-particle interaction post-production remains unaffected by the magnitude of shear.The longer polymer chain allows a greater number of possible sites for calcium crosslinking per chain which enhances the formation of a percolating network and increases the number of rheologically-effective network crosslinks. As a result, high M-w alginate fluid gels exhibit faster gelation kinetics and greater viscosities than those of low M-w alginate fluid gels.Particle stiffness increases with increasing CaCO3 concentration until a critical value is reached. Quiescent gels display the same CaCO3 critical value, suggesting that the number of crosslinks within an individual fluid gel particle is equivalent to that of their counterpart quiescent gel. This is due to the fast coil-dimer transition which, under the applied shear field, leads to kinetically trapped fluid gel structures. However, their textural response differs from that of a quiescent gel which is likely caused by the bridging between fluid gel particles.In addition to advancing the understanding of the production of fluid gels from alginates, this work shows for the first time how the ordering kinetics and the resulting particle properties can be manipulated by the choice of alginate M-w and CaCO3 concentration, potentially allowing the design and delivery of specific structures with desirable attributes. (C) 2014 Elsevier Ltd. All rights reserved.