IRON-BINDING ACTIVITY OF SOY-SAUCE

The iron-binding activities of components in soy sauce were examined b y using gel filtration chromatography. Soy sauce was separated into 5 fractions (P l-P 5) by Sephadex G-25 column chromatography monitored b y the absorbance at 275 and 400nm. Iron in soy sauce was mainly bound to high-molecular-weight components (P I and P 2). Simulated soy sauce consisting of sugars, amino acids, organic acids, and minerals was an alyzed by the same column chromatography. Iron in the simulated soy sa uce was eluted near P 3. Irons bound to P 1 and P 2 were released by a scorbic acid and ethylene diamine tetraacetic acid, but they were litt le liberated by the treatment of trypsin, pronase, sodium dodecylsulfa te, and 2-mercaptoethanol. About half amount of bound iron was release d by the treatment of NaIO4. The iron-binding components were consider ed to be mainly formed in the process of Koji preparation, heating of soy bean and aging of soy sauce.