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CORESTA Meeting, Smoke Science/Product Technology, Jeju, 2007, SSPT 40

The effect by the side chain structure of amino acids on the generation of aromatic amines in tobacco pyrolysis

YOSHIDA S.; UWANO Y.; KUSAKABE T.
Japan Tobacco Inc., Tobacco Science Research Lab., Yokohama, Kanagawa, Japan.

2-Aminonaphthalene (2-AN) and 4-aminobiphenyl (4-ABP), which constitutes a part of aromatic amines in cigarette smoke, are listed as Group1 "human carcinogens" on IARC monograph. It has been reported that the amount of nitrogenous compounds in tobacco, especially protein which is a polymer of amino acids (AAs), contribute to the yields of aromatic amines in tobacco pyrolysis. The aim of this study is to examine the effect of AAs on the generation of 2-AN and 4-ABP by focusing on the side chain structure of AAs.For preparation of the sample, aqueous solutions of asparagine, proline, alanine, and phenylalanine were sprayed onto cut flue-cured tobacco (5% w/w respectively). The control sample was prepared by adding water to the same tobacco as mentioned above. Individual AAs and five tobacco samples were pyrolyzed respectively by an infrared furnace in nitrogen atmosphere up to 800°C. 2-AN and 4-ABP collected on Cambridge pad were determined by GC/MS after solid phase extraction and derivatization. The results showed that; 1) Addition of asparagine, proline, and alanine to tobacco increased yields of 2-AN and 4-ABP, although pyrolysis of three AAs yielded quiet small amounts of aromatic amines. 2) Addition of phenylalanine to tobacco increased the generation of 4-ABP higher than that of the other AAs, but increased 2-AN generation only 1.5-fold, although pyrolysis of phenylalanine yielded both aromatic amines 150-fold, an amount that was as large as that of the other AAs. Considering the results; a) Yields of 2-AN in tobacco pyrolysis were only slightly affected by the side chain structure of AAs, and estimated that it depends mainly on the nitrogen content of AAs. b) There is a possibility that the amount of 4-ABP in tobacco pyrolysis may be affected by phenyl structure in the side chain of AAs.