Although known as an important source
of nutritive protein, these fermented soybeans have been described
to possess biological activities such as anticancer [3], antidiabetic [4],
antimicrobial [5], and antioxidant activities [6]. Such activities can
be described by the ability of antioxidants present in soy-fermented
foods to scavenge free radicals responsible for oxidative damage of
biomolecules (i.e., lipids, nucleic acids, and proteins). Recently, more
and more researchers have paid a great attention to natural antioxidants
of fermented soybeans [1,2,6]. Most of these antioxidants are poly
phenolic compounds functioning as metal chelators, reducing agents,
and singlet oxygen quenchers. Of these, isoflavones (i.e., genistein and
daidzein) are found at high concentration and they are known to act
against some diseases such as cancer [7] and atherosclerosis