Controlled assembly of crystalline triglyceride nanoplatelets

可食用脂肪是一种特殊的软凝聚物质，由结晶性甘油三酯纳米小片组成的分形胶体聚集体构成。但这种结构是分层次的，从分子组成到定义明确的纳米级，再到定义不那么明确的中尺度结构。为了控制和设计材料的结构和性能，有必要在所有长度尺度上了解和控制结构的形成。按照我们最初的长期目标，即在食品中建立结构和功能之间的关系，我们在这里建议学习如何使用在上一轮资助中开发的技术和原理来控制晶体纳米小片的中尺度组装。一系列同源的纯甘油三酯(TAG)将被用来将分子结构与所得到的纳米和中尺度结构联系起来。接下来将对饱和和不饱和标签的简单二元混合物进行研究，这将使我们更接近真实的系统。这反过来将为创造更接近真正的油的多组分标签混合物铺平道路。然后我们将能够建立分子组成、纳米结构和中尺度结构之间的关系。还将确定外场对结构形成的影响，包括过饱和度、冷却速度和剪切速度。我们的同步加速器超小角X射线散射(USAXS)技术将是这些研究中使用的主要工具。另一组实验将集中在不同化学成分但功能相似的材料之间的结构和宏观功能方面的比较。高反式、化学酯交换和棕榈油为基础的材料将进行比较，试图定义不同应用的理想结构(在所有长度的尺度上)。这不仅允许针对特定的结构，还将允许公司用更健康的脂肪取代生理上“不好的”脂肪。该项目的第二阶段将专注于研究食品基质中脂肪的结晶行为和结构。食物基质中的非甘油三酯成分和分散状态会影响成核和生长事件，以及大规模结构的形成。我们建议描述分散体系、面团和肉类基质中脂肪晶体网络结构的特征。这些信息将对食品基质中脂肪的原位结构进行指纹识别，从而决定最终产品的性质。将有助于更好地理解限制、成核抑制和增强的影响，以及多晶材料的生长调节。最后，在实际食品系统中所需的结构和功能方面所获得的知识将使我们能够设计具有与脂肪相似的功能的聚合物油凝胶系统，然而，主要由液体油组成。

Edible fats are a special category of soft condensed matter, structured as fractal colloidal aggregates of crystalline triglyceride nanoplatelets.  This structure is hierarchical, from molecular composition to a well-defined nanoscale, to a less well-defined mesoscale structure. In order to control and engineer material structure and properties, it is necessary to understand and control structure formation at all length scales. Following our original long-term objective to establish relationships between structure and functionality in foods, here we propose to learn how to control the mesoscale assembly of crystalline nanoplatelets using the techniques and principles developed during the last round of funding. A homologous series of pure triglycerides (TAGs) will be used to relate molecular structure to resulting nanoscale and mesoscale structure. This will be followed by studies on simple binary mixtures of saturated and unsaturated TAGs, which should get us closer to real systems. This, in turn, will pave the way for the creation of multicomponent mixtures of TAGs that more closely resemble real oils. We will then be able to establish relationships between molecular composition, nanoscale structure and mesoscale structure. The effects of external fields on structure formation, including supersaturation, cooling rate and shear rate will also be determined. Our synchrotron ultra-small angle X-ray scattering (USAXS) technique will be the main tool used in these studies. Another set of experiments will focus on the comparison between materials of different chemical compositions but similar functionalities, in terms of structure and macroscopic functionality. High trans, chemically interesterified and palm oil based materials will be compared to try to define the ideal structure (at all length scales) for different applications. This will not only allow for specific structures to be targeted but also would allow companies to replace physiologically "bad" fats with more healthful ones. A second stage in the project will focus on the study of crystallization behavior and structure of fat in food matrices. Non-triglyceride components and dispersion state in a food matrix can affect nucleation and growth events, as well as large scale structure formation. We propose to characterize the structure of fat crystal networks in dispersed systems, dough and meat matrices. This information will fingerprint the in-situ structure of fat in food matrices, responsible for final product properties. Contributions towards a better understanding of the effects of confinement, nucleation inhibition and enhancement, as well as growth modulation of polycrystalline materials will be made. Finally, knowledge gained on the required structures and functionality in real food systems will allow us to design polymer oleogel systems with similar functionality as fat, however, composed mainly of liquid oil.**