1. Laboratory of Food Chemistry, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
2. Nippon Del Monte Corporation, 3748 Shimizu-cho, Numata, Gunma 378-0016, Japan
3. Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands