Abstract
1-Methyl-1, 2, 3, 4 tetrahydro-β-carboline-3-carboxylic acid (MTCA) and 1-furyl-β-carboline (1-F-BC) in 25 brands of soy sauce were determined by high-performance liquid chromatography. The concentration of MTCA in Koikuchi Shoyu (regular fermented) and Koikuchi Shoyu (semi-fermented) was 486 (mean) and 252 (mean) μg/ml, respectively, and the concentration of 1-FC-BC was 0.159 (mean) and 0.072 (mean) μg/ml, respectively. Although the contents of MTCA were not changed by heating, those of 1-F-BC were increased. Soy sauce was mutagenic to S. typhimurium TA100 without S-9 mixture before and after nitrite treatment. The mutagenic activities of Koikuchi Shoyu (regular fermented) and Koikuchi Shoyu (semi-fermented) were 21, 000 (mean) and 13, 900 (mean) His+ revertants/ml, respectively. The mutagenic activities were increased by heating in both cases before and after nitrite treatment. The relationship between the contents of MTCA and 1-F-BC and mutagenicity is also discussed.
