Abstract
The iron-binding activities of components in soy sauce were examined by using gel filtration chromatography. Soy sauce was separated into 5 fractions (P1-P5) by Sephadex G-25 column chromatography monitored by the absorbance at 275 and 400nm. Iron in soy sauce was mainly bound to high-molecular-weight components (P1 and P2). Simulated soy sauce consisting of sugars, amino acids, organic acids, and minerals was analyzed by the same column chromatography. Iron in the simulated soy sauce was eluted near P3. Irons bound to P1 and P2 were released by ascorbic acid and ethylene diamine tetraacetic acid, but they were little liberated by the treatment of trypsin, pronase, sodium dodecylsulfate, and 2-mercaptoethanol. About half amount of bound iron was released by the treatment of NaIO4. The iron-binding components were considered to be mainly formed in the process of Koji preparation, heating of soy bean and aging of soy sauce.
