1. Science of Polymeric Materials, Department of Biomaterial Sciences; Graduate School of Agricultural Life Sciences, The University of Tokyo; 1-1-1 Yayoi, Bunkyo-ku Tokyo 113-8657 Japan
2. Ensuiko Sugar Refining Co., Ltd; 1-1-1, Fukuura, Kanazawa-ku, Yokohama Kanagawa 236-0004 Japan
3. Department of Applied Biological Chemistry; Graduate School of Agricultural and Life Sciences, The University of Tokyo; 1-1-1, Yayoi, Bunkyo-ku Tokyo 113-8657 Japan