1. Department of Physical Chemistry, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
2. Department of Chemistry, Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739, Japan
3. Department of Food Science, Stocking Hall, Cornell University, Ithaca, New York 14853