Characterization of the microstructure of phase segregated amylopectin and β-lactoglobulin dry mixtures
Characterization of the microstructure of phase segregated amylopectin and β-lactoglobulin dry mixtures
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DOI：
10.1007/s11483-007-9041-8
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发表时间：
2007-12-01
期刊：
影响因子：
3
通讯作者：
Bergenstahl, Bjoern
中科院分区：
文献类型：
--
作者：
Quiroga, Carmen Carla;Bergenstahl, Bjoern
采用原子力显微镜（AFM）和透射电子显微镜（TEM）研究了不同浓度、不同多糖和蛋白质比例的溶液在干燥过程中形成的相分离的支链淀粉（AP）和β-乳球蛋白（β-lg）混合物的微观结构。以原子力显微镜（AFM）为主要技术手段，用透射电镜（TEM）对结果进行了验证。只有一种组分，AP或β lg的系统，显示出均匀的结构。当多糖和蛋白质处于同一体系中时，它们发生相分离，相之间存在尖锐的边界。根据相分离样品的表面形态的类型，它们被分组为：域润湿的空气-水表面和域似乎是沉浸在固体膜。域的尺寸范围从约几纳米到约几微米变化很大，这是由动力学原因或由样品的膜结构给出的限制决定的。两相体系是AP与β Ig比率高于约1：3的AP-连续相和比率低于约1：6的β Ig-连续相。在这些比率之间，系统似乎或多或少是双连续的。的形态，以及其在相图中的位置建议的旋节相分离。在亚稳区（AP与β Ig的比率为3：1）中也观察到相分离，尽管域较小且不太发达，并且其被解释为双节点相分离。
The microstructure of phase-segregated amylopectin (AP) and beta-lactoglobulin (beta lg) mixtures formed during drying from solutions with different concentrations and different polysaccharide and protein ratios have been studied using atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM was used as the main technique and TEM was used to confirm the results. Systems with only one of the components, AP or beta lg, displayed even structures. When the polysaccharide and the protein were in the same system they phase segregated with a sharp boundary between the phases. According to the type of surface morphology of the phase-segregated samples, they were grouped into: domains wetting the air-water surface and domains appearing to be immersed in the solid film. The size range of the domains varied widely from about some nanometers to about a few micrometers which was determined by kinetic reasons or by restrictions given by the film structure of the sample. The two phase systems were AP-continuous phase at AP to beta lg ratios above about 1:3 and beta lg-continuous phase at ratios below about 1:6. Between these ratios, the systems appeared more or less bicontinuous. The morphology as well as its position in the phase diagram suggested a spinodal phase separation. Phase separation was also observed in the metastable region (AP to beta lg ratio 3:1), although the domains were smaller and less developed and it was interpreted as binodal phase separation.