1. Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
2. Kumamoto Flour Milling Co., Ltd. Hanazono-1, Kumamoto 860-8625, Japan.
3. Corresponding author. Phone and Fax: (81)992858641. E-mail: takeda@chem. agri.kagoshima-u.ac.jp