1. Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden; Rapid Methods Section, Leatherhead Food RA, Randalls Road, Leatherhead, Surrey KT22 7RY, United Kingdom; and Institut für Technische Chemie - TC 8, Technische Universität Berlin, Strasse d. 17 Juni 124, 10623 Berlin, Germany