It is intended to easily separate saponins from isoflavones extracted from
starting soybeans thereby giving highly pure saponins at a high yield on
an industrial scale. Saponins can be highly efficiently separated from
isoflavones by performing multistage extraction under mild conditions
such that malonyl isoflavone glycoside, from among isoflavones contained
in the starting soybeans, is not converted into isoflavone glycoside,
acetyl isoflavone glycoside or isoflavone aglycon. Thus, highly pure
saponins can be obtained at a high yield on an industrial scale.
