1. Laboratory of Food Chemistry, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
2. Corresponding author. Phone: (+32)-16-321634. Fax (+32)-16-321997. E-mail: kristof.brijs@agr.kuleuven.ac.be
3. Grain Research Laboratory, Canadian Grain Commission, 1404-303 Main Street, Winnipeg MB R3C 3G8, Canada.