Quantitative Assessment of Triacylglycerol Crystallite Thickness by 1H Spin-Diffusion NMR

Properties and consumer appreciation of fat containing food products are greatly influenced by the growth of the. fat crystalline domains and their morphology. Various analytical methods can be exploited to provide insight into the multilength scale microstructure of fat networks, but very few are able to discriminate structural features between different ways of processing fats. We selected in this work methods that highlight the mesostructure of fat crystalline systems. In this respect, spin diffusion NMR and XRD methods were employed to-determine the fat crystallite thicknesses (crystalline domain size). This is the first attempt to quantify the mesostructure domains of triglyceride:based fat crystals, by means of H-1 spin-diffusion NMR experiments. The crystalline domain sizes determined by spin-diffusion NMR were found to be in good agreement with the crystallite thickness determined by the Scherrer analysis of the first order diffraction line from SAXS data. These results demonstrate the ability of the NMR technique to characterize the mesostructure of fats in a quantitative manner. This method is of particular interest for the structure analysis of fats, especially because of the possibility to quantify the size of the crystalline domains in diluted systems where scattering techniques struggle with the amount of diffracting material.