Nanoscale Engineering of the Structure and Functionality of Fat and Oleogel Systems

A.G. Marangoni, N.C. Acevedo, M.F. Peryonel, D.A. Pink
University of Guelph,
Canada

Keywords: nanostructure, triaclyglycerol, crystalline nanoplatelet, mesoscale, crystallization

Summary:

Fats and oils are extremely useful natural products which are widely used in foods, cosmetics and industrial applications. As the concern for the environment and health grows, consumers are demanding more natural, green and sustainable materials in everyday consumer products. Fats and oils are complex multicomponent mixtures of triacylglycerol molecular species. The nature of these molecular species are a function of both fatty acid composition and distribution within the TAG molecule. The purpose of this talk is to discuss the structure of fats and oils, from constituent TAG molecules to the crystals they form. Upon crystallization, TAG molecules form lamellae which stack epitaxially to form highly asymmetric nanoplatelets. These nanoplatelets rapidly aggregate into colloidal structures of differing morphologies and size depending on external fields and concentration, forming networks which are responsible for the binding of oil, water vapour barrier properties, and mechanical properties of the fat. Our work has focused on developing and understanding of the functionality of fats from a structural perspective. Early work focused on the quantification of structure using small deformation rheological techniques. More recent work has focused on the use of scattering methods, in particular Ultra-Small Angle X-ray Scattering at synchrotron facilities to quantify atomic scale structure to mesoscale structure simulataneously, in a non-destructive fashion. These scattering patterns yield information on the size of the scattering units and the spatial distribution of mass of these scatterers. We then relate this structural fingerprint to macroscopic functionality. In this talk we will outline the discovery of the nanoscale in fat crystal networks, the development of techniques to characterize it and finally attempts at relating this structural length scale to functionality of fats. The design of fat mimetics that possess functional characteristics similar to those of edible fats minus excessive amount of saturated fats and zero trans fats is a very important field of food materials science endeavor. Here we will briefly summarize the different strategies available to structure liquid oil into a semi-solid gel-like structure, i.e., an oleogel, to replace edible fats. Nanoscale design considerations will be highlighted. A final perspective of future challenges will be offered.