高速射流改性木薯淀粉及其与瓜尔豆胶的界面行为研究

Starch and hydrocolloids as two kinds of important functional polymer, which usually common used in food system. Researches found that the starch-hydrocolloids compound substitution with single hydrocolloids which does not change the original flavor, the sensory characteristics of food, and also reduce the production cost. In addition, studies also found that hydrocolloids combination with some of the modified starch is better than the native starch. However, the mechanism is still not completely known between starch and hydrocolloids. Thus, the study intends to select cassava starch as raw materials and investigate the interaction between modified cassava starch and guar gum. The physicochemical properties of rheological, viscosity, thermodynamics, etc, are measured by such as rheometer, rapid viscosity analyzer, differential scanning calorimetry. The structure change are determined with such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy, etc. Based on the technical methods of molecular simulation, dielectric relaxation spectroscopy, nuclear magnetic resonance, etc, the interface behavior between guar gum and modified cassava starch would be revealed. Our study may provide theoretical basis for starch-hydrocolloids mixed system and has the good practical significance to explore the application value of starch and hydrocolloids.

淀粉与亲水性胶体作为食品体系中两类重要的功能性高分子, 通常被共同应用于食品体系。研究表明将淀粉-亲水胶体复配物替代单一的亲水胶体，其复配物在替代胶体的同时不改变食品原有的风味、感官特性，并且还减低了生产成本。另外，还发现亲水胶体与一些改性后的淀粉复配效果较原淀粉要更好。然而，淀粉与亲水胶体之间的作用机理仍未完全可知。为此，本项目拟选用木薯淀粉为原料，经过改性之后，研究其于瓜尔豆胶的相互作用，借助流变仪、快速粘度分析仪、差示扫描量热仪等技术分析其理化性质（流变、粘度、热力学等）；采用扫描电镜、透射电镜、原子力显微镜等技术表征其结构变化；并结合分子模拟，介电松弛谱，核磁共振等手段揭示其与瓜尔豆胶的界面行为。本项目可为淀粉-亲水胶体复配体系提供理论基础，并对开拓淀粉和亲水性胶体的应用价值具有很好的现实意义。

淀粉与亲水性胶体作为食品体系中两类重要的功能性高分子,常被同时应用于食品体系。研究表明将淀粉-亲水胶体复配物替代单一的亲水胶体，复配体系不仅保持食品原有的风味以及感官特性，而且还降低了生产成本。另外，还发现亲水胶体与一些改性后的淀粉复配效果较原淀粉要更好。然而，淀粉与亲水胶体之间的作用机理仍未完全可知。本项目选用木薯淀粉为原料，经过高速射流处理后，研究其与瓜尔豆胶的相互作用，并深入揭示其作用机理。主要研究内容和结果如下：(1)高速射流改性木薯淀粉研究：研究了木薯淀粉经不同压力(60、100、140、180、220 MPa)高速射流处理2次对木薯淀粉的粒度、微观结构、冻融稳定性、溶解性、热力学、流变特性以及羟基变化的影响。结果表明木薯淀粉的粒度显著增加，颗粒结构严重破坏，发生部分糊化，但是晶体类型不变，结晶度降低；溶解性提高，冻融稳定性下降，羟基暴露，出现剪切变稀现象。(2)高速射流改性木薯淀粉-瓜尔豆胶体系研究及机理分析：研究了不同质量配比(高速射流改性木薯淀粉:瓜尔豆胶=0.1:0、0.09:0.01、0.08:0.02、0.07:0.03、0.06:0.04 g)的高速射流改性木薯淀粉-瓜尔豆胶混合体系的流变特性以及以质量配比(0.06:0.04 g)高速射流处理改性木薯淀粉-瓜尔豆胶混合体系为研究对象，研究高速射流对混合体系流变特性以及结构的影响。结果表明随着瓜尔豆胶添加量的增加，混合体系的粘度、剪切应力、贮能模量(G′)、损耗模量(G″)逐渐增加，且G′＞G″，tanδ 逐渐减小。同时随着高速射流处理压力的增加，高速射流处理改性木薯淀粉-瓜尔豆胶混合体系(高速射流改性木薯淀粉：瓜尔豆胶=0.06:0.04 g)的粘度、剪切应力、G′、G″逐渐增加，且G′＞G″，tanδ 逐渐减小，晶体类型没有发生变化，结晶度逐渐上升，氢键逐渐减少，凝胶结构增强。另外，利用流体动力学对高速射流装置进行了模拟分析，同时，结合分子模拟手段对木薯淀粉与瓜尔胶的相互作用方式进行了初步的探讨。本项目可为淀粉-亲水胶体复配体系提供理论基础，并对开拓淀粉和亲水性胶体的应用价值具有很好的现实意义。