OCCURRENCE OF TETRAHYDRO-BETA-CARBOLINE-3-CARBOXYLIC ACIDS IN COMMERCIAL FOODSTUFFS

The occurrence of tetrahydro-beta-carboline-3-carboxylic acids (TH bet a C-3-COOHs) in foodstuffs was investigated. Spectral and chromatograp hic data showed the occurrence of 1,2,3,4-tetrahydro-beta-carboline-3- carboxylic acid (THCA) and hyl-1,2,3,4-tetrahydro-beta-carboline-3-car boxylic acid (MTCA) in foodstuffs. The content of TH beta C-3-COOHs gi ven as a sum of both THCA and MTCA was as follows: soy sauce, 94-517 m g/L; seasoning, 0.75-32.8 mu g/g; table wine, 1.7-6.6 mg/L; beer, 0.3- 17.9 mg/L; cider, 0.06-0.2 mg/L; liquor, 0-7.6 mg/L; nine vinegar, 3.9 -9.7 mg/L; cider vinegar, 0.19-1 mg/L; yogurt, 0.05-0.15 mu g/g; chees e, 0-3.4 mu g/g; soft drinks, 0-0.45 mg/L; fruit juices, 0.1-5.1 mg/L; smoked fish, 0.08-0.4 mu g/g; and bread, 0.16-3 mu g/g. Usually MTCA was the major substance within TH beta C-3-COOHs, but bread and smoked fish contained more THCA. Experiments in which foodstuffs were spiked with formaldehyde and acetaldehyde proved the chemical formation of T HCA and MTCA, respectively. It is concluded that the exogenous intake of these substances during the human ingestion of foods may be partial ly responsible of the reported endogenous presence of TH beta C-3-COOH s in the human biological tissues and fluids.