1. Department of Nutritional Toxicology, Institute for Nutrition, Friedrich-Schiller-University, Dornburger Strasse 25, D-07743 Jena, Germany, Geisenheim Research Center, Section Wine Chemistry and Beverage Technology, Ruedesheimer Strasse 28, D-65366 Geisenheim, Germany, and Department of Food Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany