1. National Research Institute of Vegetables, Ornamental Plants and Tea, 2769 Kanaya, Shizuoka 428-8501, Japan, Laboratory of Food Science, Department of Food Science and Technology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan, and Faculty of Human Life Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502, Japan