T Nagata1, Y Ando1,2, A Hirota1,3. 1. a Kyushu National Agricultural Experiment Station , Nishigoshi-cho , Kumamoto 861-11 , Japan. 2. b National Research Institute of Vegetables, Ornamental Plants, and Tea , Kanaya-cho , Shizuoka 428 , Japan. 3. c School of Food and Nutritional Sciences, University of Shizuoka , Yada , Shizuoka 422 , Japan.