Global Small-Angle X-ray Scattering Data Analysis of Triacylglycerols in the α-Phase (Part II).

Abstract

The early-stage crystallization behavior in a triacylglycerol mixture has been investigated on the nanoscale with a novel global small-angle X-ray scattering analysis technique. This method has been tailored for the determination of the electron density profiles (EDPs) replicating both (i) the nanostructural texture of molten triacylglycerols (TAGs) (refer to "Global Small-Angle X-ray Scattering Data Analysis of Triacylglycerols in the Molten State (Part I)" of this publication series) and (ii) the lamellar structure of the metastable α-polymorph. In a first stage, the α-phase scattering contribution alone was examined by classical Fourier analysis as well as by globally fitting the data, leading to practically identical EDPs. On the basis of these findings, we extended our analysis to the entire X-ray scattering contribution arising from molten TAGs and the solid α-phase fraction. Remarkably, the experimental and theoretical data agree very well, providing for the first time a detailed nanostructural understanding about the coexisting molecular assemblies. This, in turn, also allowed us to quantitatively determine the solid fat content (SFC) with X-ray scattering data. Our new theoretical approach for measurement of SFC is based on the global analysis of small-angle scattering/diffraction patterns, and the SFC results are in good agreement with values obtained from other techniques such as NMR spectroscopy.