⇑ Corresponding author. Present address: Food Research Institute, National
Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki
305-8642, Japan. Tel.: +81 29 838 8094; fax: +81 29 838 8041.
E-mail address: ippoushi@affrc.go.jp (K. Ippoushi).