Controlled assembly of crystalline triglyceride nanoplatelets

食用脂肪是一类特殊的软凝聚物质，其结构为结晶甘油三酯纳米片的分形胶体聚集体。 这种结构是分层的，从分子组成到定义明确的纳米尺度，再到定义不太明确的中尺度结构。为了控制和工程材料的结构和性能，有必要了解和控制所有长度尺度的结构形成。根据我们最初的长期目标，建立食品结构和功能之间的关系，在这里，我们建议学习如何使用上一轮资助期间开发的技术和原理来控制晶体纳米片的介观组装。纯甘油三酯（TAG）的同源系列将用于将分子结构与所得的纳米级和中尺度结构相关联。随后将对饱和和不饱和TAG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。反过来，这将为创造更接近真实的油的多组分TAG混合物铺平道路。然后，我们将能够建立分子组成，纳米结构和介观结构之间的关系。还将确定外场对结构形成的影响，包括过饱和度、冷却速率和剪切速率。我们的同步辐射超小角X射线散射（USAXS）技术将是在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比较，在结构和宏观功能方面。高反式，化学酯交换和棕榈油基材料将进行比较，试图定义不同应用的理想结构（在所有长度尺度）。这不仅可以针对特定的结构，还可以让公司用更健康的脂肪取代生理上“坏”的脂肪。该项目的第二阶段将侧重于研究食品基质中脂肪的结晶行为和结构。食品基质中的非甘油三酯组分和分散状态可以影响成核和生长事件，以及大规模结构的形成。我们建议在分散系统，面团和肉类基质的脂肪晶体网络的结构特征。这些信息将对食品基质中脂肪的原位结构进行指纹识别，负责最终产品的特性。有助于更好地了解约束，成核抑制和增强，以及多晶材料的生长调制的影响。最后，在真实的食品系统中所需的结构和功能上获得的知识将使我们能够设计具有与脂肪相似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.