1. Division of Human Nutrition and Epidemiology, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands; Department Food Processing, Agrotechnological Research Institute (ATO), P.O. Box 17, 6700 AA Wageningen, The Netherlands; and State Institute for Quality Control of Agricultural Products (RIKILT), P.O. Box 230, 6700 AE Wageningen, The Netherlands