1. 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; Food Research Laboratories, Mitsui Norin Company Ltd., 223-1 Miyabara, Fujieda-shi, Shizuoka 426-0133, Japan; and Graduate School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan