Characterization of the Nanoscale in Triacylglycerol Crystal Networks

Abstract

Here we report on the characterization of the nanoscale in triacylglycerol crystal networks of edible fats. Blends of tristearin and triolein were prepared in proportions between 20 and 100% w/w to achieve a wide range of supersaturations. Crystal networks were subjected to mechanical disruption using isobutanol at 10 °C and visualized using cryogenic transmission electron microscopy (cryo-TEM). This method allowed the breakdown of spherulitic structures into their primary crystals: nanoplatelets of approximate sizes 150 × 60 × 30 nm to 370 × 160 × 40 nm depending on supersaturation conditions, and a length to width aspect ratio of 2.3. The method also allowed the visualization of bimolecular triacylglycerol lamellae within a cross-section of a nanoplatelet. The tristearin d-spacing (∼4.5 nm) and domain size (30−50 nm) of the (001) plane, by cryo-TEM and small-angle X-ray diffraction, agreed quantitatively. Scherrer analysis provided an accurate estimate of the cross-sectional thickness of the nanoplatele...