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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Poster: Biopolymers and Biomaterials

CPP 28.2: Poster

Mittwoch, 24. März 2010, 17:30–19:00, Poster C

Modification of casein films by rennin enzyme action — •Ronald Gebhardt^1,2, Ulrich Kulozik¹, Christian Riekel², Manfred Burghammer², and Peter Müller-Buschbaum³ — ¹TU München, Chair for Food Process Engineering and Dairy Technology, Weihenstephaner Berg 1, 85354 Freising-Weihenstephan, Germany — ²European Synchrotron Radiation Facility, Grenoble, France — ³TU München, Physik Department E13, Garching, Germany

The aim of our research is the development of new functional materials on the basis of natural products. As a model system we investigated films of casein micelles whose properties were consciously changed. Beside imaging techniques like AFM, we used grazing incidence small angle X-ray scattering with a micrometer-sized X-ray beam (so called microGISAXS) to investigate the micro- and nanostructure of protein films. The method provides information about the multilevel-structure of casein micelles with high positional accuracy and statistical relevance. We used two different approaches in order to modify the casein film structure by rennin. When added to casein solution prior to film preparation, rennin generated homogeneous particle films by transforming casein micelles into para-casein micelles. Contrary, the coating of casein films by rennin led to a surface near transformation into para-casein-micelles only, while casein micelles inside the film kept their native structures. The latter results will be explained on the basis of a diffusion model (1). (1) R. Gebhardt, M. Burghammer, C. Riekel, U. Kulozik, P. Müller-Buschbaum: Dairy Sci. Technol. (2009) accepted