1. Laboratory of Food Chemistry, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, B-3001, Heverlee, Belgium.
2. Corresponding author. Phone: +32-16-321634. Fax: +32-16-321997. E-mail: wim.veraverbeke@agr.kuleuven.ac.be
3. Grain Quality Research Laboratory, CSIRO Plant Industry. P.O. Box 7, North Ryde, NSW 1670, Australia.