University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
Carbohydr Polym. 2015 May 5;121:254-64. doi: 10.1016/j.carbpol.2014.12.059. Epub 2015 Jan 3.
The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).
本文旨在研究不同浓度（2-5%）和糊化度的普通马铃薯淀粉（NPS）糊的流变性不稳定性（触变性和/或反触变性）。进行了带有滞后环的流动曲线、恒剪切率下的表观粘度和剪切结构恢复试验。还研究了颗粒大小分布、相应淀粉悬浮液的糊化特性以及糊的透光率、颗粒淀粉的分子量和多分散性及其在 80、95 和 121°C 下制备的糊的透光率。糊化度取决于温度和浓度，并强烈影响糊的流变性。所有的糊都属于剪切变薄的非牛顿液体，在不同程度上表现出流变不稳定性。触变性与糊中淀粉颗粒的大小和数量有关，并取决于所使用的测量方法。在 80°C 糊化的 2%和 3%的样品中，颗粒的溶胀占主导地位，而破坏则次之（观察到触变性）。在其他样品中，破坏占主导地位，溶胀则次之（观察到反触变性）。
