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: veerle.derycke@biw.kuleuven.be
3. Master Foods, Industrielaan 5, B-2250 Olen, Belgium.
4. R&R Research Services Inc., 8831 Quail Lane, Manhattan, KS 66502, USA.