1. Research and Development Division, Kagome Co., Ltd., 17 Nishitomiyama, Nasushiobara, Tochigi 329-2762, Japan.
2. Functional Biomolecules Research Group, NARO Institute of Livestock and Grassland Science, Tsukuba, Ikenodai 2, Ibaraki 305-0901, Japan.
3. Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba, Sendai 981-8555, Japan.