The formation of the crystalline structure of milk fat, palm oil and cocoa butter under controlled shear, temperature and cooling rate conditions was observed in-situ using synchrotron x-ray radiation diffraction and a Couette-Taylor cell. The shear rates explored ranged from 45 s -1 to 2880 s-1, at selected temperatures between 17 and 25°C. Most experiments were conducted at cooling rates of 3°C/min, but some were done at 0.5°C/min.

We developed methods to analyze the asymmetric 2D images, and thus we documented for the first time the orientation of crystallites and the generality of the acceleration of phase transitions due to shear, and proposed a conceptual model to understand the effect of shear in the progressive variation of the diffraction peak position.

We discovered a new shear induced phase in cocoa butter, obtained a low temperatures and shear rates, that we called phase X. Phase X was found under static conditions and slow cooling rate as well. We reported for the first time that under shear cocoa butter can go to phase V through phase IV.