Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: SYBM Bioinspired Materials

MM 35.22: Poster

Donnerstag, 29. März 2007, 18:45–20:45, H16

Effect of calcium concentration on the structure of casein micelles in thin films — •Ronald Gebhardt¹, Ali Ezzeldin Metwalli², Stephan Volkher Roth³, Wolfgang Doster², and Peter Müller-Buschbaum² — ¹European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France — ²TU München, Physik Department LS E13, James-Franck-Str.1, 85748 Garching (Germany) — ³HASYLAB at DESY, Notkestr. 85, 22603 Hamburg (Germany)

Caseins are organized in poly-disperse, roughly spherical aggregates with diameters ranging between 150 and 300 nm. They represent with about 80% the largest protein component in milk. The casein micelle of bovine milk consists of four different phosphor-proteins which can be divided into two groups: the calcium insensitive κ-casein and the calcium sensitive αS1-, αS2- and β-caseins. Casein micelles are the raw material for the production of gelled and flocculated milk products, such as cheese, yogurt and ice-cream. Additionally, casein micelles find a broad application in casein films as adhesives or paint, prepared with solution casting or spray coating techniques.

We have investigated the effect of calcium on the structure of casein micelles in thin films using grazing incidence small angle x-ray scattering (GISAXS) at the BW4 USAXS beamline at HASYLAB/DESY in Hamburg. The GISAXS measurements are complemented with optical microscopy and atomic force microscopy to picture the surface structure [1].

[1] Müller-Buschbaum P., Gebhardt R., Maurer E., Bauer E., Gehrke R., Doster W. (2006) Biomacromolecules 7, 1773-1780