1. Technical University of Munich, Department of Chemical-Technical Analysis and Chemical Food Technology, Weihenstephaner Steig 23, D-85354 Freising-Weihenstephan, Germany, Research Center Weihenstephan for Brewing and Food Quality, Alte Akademie 3, D-85354 Freising-Weihenstephan, Germany, and Adalbert-Raps Research Center, Am Forum 3, D-85350 Freising-Weihenstephan, Germany