Structural characterization of casein micelles: shape changes during film formation.
The objective of this study was to determine the effect of size-fractionation by centrifugation on the film structure of casein micelles. Fractionated casein micelles in solution were asymmetrically distributed with a small distribution width as measured by dynamic light scattering. Films prepared from the size-fractionated samples showed a smooth surface in optical microscopy images and a homogeneous microstructure in atomic force micrographs. The nano- and microstructure of casein films was probed by micro-beam grazing incidence small angle x-ray scattering (μGISAXS). Compared to the solution measurements, the sizes determined in the film were larger and broadly distributed. The measured GISAXS patterns clearly deviate from those simulated for a sphere and suggest a deformation of the casein micelles in the film.
Technische Universität München, Chair for Food Process Engineering and Dairy Technology, Weihenstephaner Berg 1, 85354 Freising-Weihenstephan, Germany. ronald.gebhardt@tum.de
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Vendrely
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Kulozik
D000818:Animals; D002364:Caseins / Q000032:analysis* / Q000737:chemistry; D002614:Chelating Agents / Q000032:analysis* / Q000737:chemistry; D008823:Micelles; D018625:Microscopy, Atomic Force; D008892:Milk / Q000737:chemistry; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry; D010316:Particle Size; D053838:Scattering, Small Angle; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D014961:X-Ray Diffraction
D002364:Caseins; D002614:Chelating Agents; D008823:Micelles; D012996:Solutions