Controlled assembly of crystalline triglyceride nanoplatelets

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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.**