1. Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, U.S.A.
2. Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany.
3. Corresponding author. Phone: +49-721-608-4-2936. Fax: +49-721-608-4-7255. E-mail: mirko.bunzel@kit.edu