1. United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan.
2. Department of Research, Kumamoto Flour Milling Co., Ltd., Hanazono-1, Kumamoto 860-8625, Japan.
3. Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
4. Corresponding author. E-mail: takeda@chem.agri.kagoshima-u.ac.jp. Phone and fax: +81-99-285-8641.