1. Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden, Division of Food Biotechnology, Department of Food Sciences and Technology, BOKU-University of Natural Recources and Applied Life Sciences Vienna, Muthgasse 18, A-1190 Wien, Austria, and Research Centre Applied Biocatalysis, Petersgasse 14, A-8010 Graz, Austria