1. Research Center for Basic Science, Research and Development, Quality Assurance Division, Nissin Seifun Group Inc., 5-3-1 Tsurugaoka, Oi-machi, Iruma, Saitama 356-8511, Japan.
2. Present address: Production Control Section, Production Department, Chilled and Frozen Products, Nisshin Foods Inc., 1-25, Kanda-Nishiki-cho, Chiyoda, Tokyo, 101-8441, Japan.
3. National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
4. Corresponding author. Phone: +81-29-838-8033. Fax: +81-29-838-7996. E-mail: mitsuru@nfri.affrc.go.jp