1. Katholieke Universiteit Leuven, Laboratory of Food Chemistry, Kardinaal Mercierlaan 92, B-3001 Heverlee, Belgium.
2. Corresponding author. E-mail: annemie.loosveld@agr.kuleuven.ac.be
3. Department of Food Science, Wageningen Agricultural University, P.O. Box 6700 EV, Wageningen, The Netherlands.
4. Center for Surface Chemistry and Catalysis, Kardinaal Mercierlaan 92, B-3001 Heverlee, Belgium.