1. Technische Universität München, Physik Department E13, James-Franck-Str.1, 85747 Garching, Germany, European Synchrotron Radiation Facility, bp 220, 38043 Grenoble Cedex, France,Institute Laue-Langevin, 6 rue Jules Horowitz, bp 156, 38042 Grenoble, France, and Technische Universität München, Chair for Food Process Engineering and Dairy Technology, 85354 Freising-Weihnstephan, Germany