PRESENCE OF TETRAHYDRO-BETA-CARBOLINE-3-CARBOXYLIC ACIDS IN FOODS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY AS THEIR N-METHOXYCARBONYL METHYL-ESTER DERIVATIVES

Various tetrahydro-beta-carboline-3-carboxylic acids (TH beta C-3-COOH ) are identified in commercial foods and drinks by GC-MS. Positive ide ntification of hyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) is demonstrated in and tabasco sauces, wine, beer, wine vinega r, cider, orange juice, toasted bread, blue cheese and yoghurt. 1,2,3, 4-Tetrahydro-beta-carboline-3-carboxylic acid (THCA) occurs in toasted bread, beer, cider, wine vinegar, soy and tabasco sauce, orange juice and blue cheese. MTCA and THCA are reported for the first time in sev eral of these products. MTCA appears as a mixture of two diastereoisom ers with the same mass spectra. MTCA is the major TH beta C-3-COOH in foodstuffs except for toasted bread that contains more THCA. GC-MS ana lysis of N-methoxycarbonyl methyl ester derivatives of TH beta C-3-COO Hs was used for chemical identification. Those derivatives were synthe sized in a qualitatively using methyl chloroformate or methyl chlorofo rmate and diazomethane reagents. Electron impact mass spectra of N-met hoxycarbonyl-TH beta C3-COOH methyl esters are reported and fragmentat ion assigned and discussed. These results prove the presence of TH bet a C-3-COOHs in commercial foodstuffs suggesting their uptake during th e daily consumption of foods.