1. Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, Box 2463, B-3001 Leuven, Belgium
2. German Research Center for Food Chemistry, Lise Meitner Strasse 34, D-85354 Freising, Germany