The longest day... at ESRF!

Like the SOLEIL synchrotron, also frequented by STLO teams, the ESRF is one of the “big” physics instruments available to European scientists. It carries out the same type of measurements as our “zeta” and “Malvern” light scattering and diffraction equipment, but with exceptional ranges of angles, wavelengths and resolutions. The principle of these measurements is based on the interaction between radiation and matter: as the rays penetrate the material, they are deflected at angles that reveal the intimate structures of the material and their movement, much as the sun reveals the micro-droplets of a fog and their agitation. With its extreme angles and powerful beam, the “ID02” X-ray line can reveal “bricks” of the order of ten nanometers within casein micelles, right down to interactions between micelles, or even between flocs in a gel being formed on the micrometer scale. All this in a single spectrum, and every 20 seconds during gelation!

Several experiments followed one another during these 72 hours, providing new data for the work of Erik Juste (phD student in PSF team at STLO) and Julien Bauland (former STLO doctoral student, currently a post-doctoral fellow at École Nationale Supérieure de Lyon). Thanks to the performance of the ID02 line, Erik hopes to be able to distinguish the respective behaviors of casein micelles and serum protein aggregates during the formation of a rennet gel under different conditions. Julien and Thomas are investigating the role of calcium phosphate nanoclusters in casein micelle structuring and dynamics during coagulation.

A tiring mission... but well accomplished!