1. Department of Applied Molecular Biosciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
2. Shizenshokken Co. Ltd., 293 Sakai, Bungotakada, Oita 879-0615, Japan
3. Sasaki Food Co. Ltd., 276 Sakai, Bungotakada, Oita 879-0615, Japan
4. Faculty of Education and Welfare Science, Oita University, 700 Dannoharu, Oita, Oita 870-1192, Japan