Tobacco curing

We thus assume, that the biochemical processes during tobacco curing may be different from the ui vitro N-nitrosation of secondary and tertiary amines (30). 

NT181 Hecht, S. S., C. B. Chen, N. Hirota, R. M. Omaf, T. C. Tso, and D. Hoffmann. Tobacco-specific nitrosamines formation from nicotine in vitro and during tobacco curing and carcinogenicity in strain A mice. J Natl Cancer Inst 1978 60(4) 819-824. 

NT195 Kinsler, S., D. H. Pence, W. K. Shreve, A. T. Mosberg, P. H. Ayres, and J. W. Sagartz. Rat subchronic inhalation study of smoke from cigarettes containing flue-cured tobacco cured either by direct-fired or heat-exchanger curing processes. Inhal Toxicol 2003 5(8) 819-854. 

Liquefied petroleum gas (LPG) is used for domestic and industrial heating, flame weeding, tobacco curing, grain drying, and in motor vehicles, as well as for the petrochemical industry. 

H. Jensen thinks that in so far as tobacco curing proceeds in the presence of formalin and chloroform, it. is not a bacterial process. 

Hecht et al. (1576) reported the level of NNN in tobacco paralleled the nitrate level. They also suggested the TSNA levels in tobacco may be controllable by appropriate selection of the curing process. Flue-cured tobaccos usually show the lowest NNN level vs. the levels in tobaccos cured by other methods, e.g., air-curing. 

Rormation from nicotine in vitro and during tobacco curing and carcinogenicity in Strain A mice J. Natl. Cancer Inst. 60 (1978) 819-824. 697. 

Herrmann, K. A review of literature on phenols, phenolic acids, and related compounds in green tobacco, cured tobacco, and tobacco smoke Deut. Apotheker Ztg. 101... 

Meikle, R.W. Fate of Diamidafos (phenyl N,N -dimethylphosphordiamidate) in tobacco, cured tobacco, and in smoke J. Agr. Food Chem. 25 (1977) 746-752. Meins, R, H. Shinshi, H. C Wenzler, J. Hofsteenge, J.A. Ryals, and C. Sperisen DNA sequences encoding polypeptides having beta-l,3-glucanase activity U.S. Patent No. 6,632,981 (October 14, 2003). 

Burley tobacco Cured leaves after harvest, 50-day-old whole plants 0.42 0.38 Sims Atkinson (1976) Sims et al. (1975)... 

As fuel for such operations as poultry brooding, cotton and grain drying, tobacco curing, crop dehydration, weed burning, and orchard heating. 

Potassium nitrate Tempering steel, tobacco curing, glass manufacture, explosives... 

Food apphcations utilize first and second molasses in baking (bread, cakes, cookies) for the molasses flavor. Molasses is also used in curing of tobacco and meats, in confections such as toffees and caramels, and in baked beans and glazes. 

C. O. Jensen, Chemical Changes During the Curing of Cigar Eeaf Tobacco, The Pennsylvania State College, American Chemical Socief, State College, Pa., Sept. 1951. 

The analysis of combustion products presents problems of complexity similar to that of feedstock and raw fuel analysis. A highly complex matrix of aliphatic material often exists (as unburnt fuel in the combustion exhaust), whilst the species of interest, for example, carcinogens or mutagens are often at very low concentrations. A classic example of multidimensional GC is its use in the analysis of flue-cured tobacco essential oil condensate. 

Neither endosulfan nor endosulfan sulfate was detected in surveys of the milk supply of the southern region of Ontario, Canada conducted in 1970-1971 and 1973 (Frank et al. 1975). In Burley tobacco, when the crop was harvested immediately after treatment with 0.5 pound/acre of endosulfan, the total endosulfan residue levels (isomers and sulfate) were reported to average 23.2 ppm after curing for 4 months. Average total residues decreased to 2.2 ppm when the time between treatment and harvest was increased to 28 days (Dorough et al. 1973). 

In Tobacco. At the time of harvesting, fresh tobacco leaves do not contain measurable amounts of nitrosamines (<5 ppb). However, these compounds are formed during curing, aging and fermentation. Their concentrations depend primarily on the content of proteins, alkaloids, agricultural chemicals and nitrate in the tobacco, as well as on the processing conditions which lead to the reduction of the nitrates. 

In a study for precursor determination, we stem-fed individual Burley leaves with nicotine-2 - C or nornicotine-2 - C (29). Subsequently, the leaves were air cured, dried and analyzed for NNN and NNN- C. Recovery of the p-activity in the form of NNN- C amounted to 0.009% and 0.007%, respectively of the stem-fed label. This demonstrates that both alkaloids give rise to NNN. More importantly, it points to the fact that the tertiary amine, nicotine, which constitutes 0.5-2.6% of commercial tobaccos (26,27), is the major precursor for the carcinogenic tobacco-specific NNN, while the secondary amine, nornicotine is of lesser importance because it amounts to only 0.005-0.06% in tobacco (Figure 8). 

Nonvolatile Nitrosamines In Tobacco. A method which we developed several years ago for the analysis of tobacco-specific nitrosamines (TSNA 31) involves extraction of tobacco with buffered ascorbic acid TpH 4.5) followed by partition with ethyl acetate, chromatographic clean-up on silica gel, and analysis by HPLC-TEA (Figure 9). Results obtained with this method for a large spectrum of tobacco products (Table IV), strongly support the concept that the levels of nitrate and alkaloids, and especially the methods for curing and fermentation, determine the yields of TSNA in tobacco products. Recent and as yet preliminary data from snuff analyses indicate that aerobic bacteria play a role in the formation of TSNA during air curing and fermentation. 

In April of 1982 (flue-cured tobacco) and 1983 (soybean and sunflower), treatments were set up as follows (1) mulch removed ... 

Nicotine is distilled from bnming tobacco and carried proximally on tar droplets (also called particnlate matter), which are inhaled. Absorption of nicotine across biological membranes depends on pH. Nicotine is a weak base with a p fa of 8.0. In its ionized state, snch as in acidic environments, nicotine does not rapidly cross membranes. The pH of smoke from fine-cured tobaccos, found in most cigarettes. 

Tobacco use is primarily due to psychopharmacological effects of nicotine (Henningfleld et al. 2006). Nicotine is a tobacco alkaloid, a basic substance that contains a cychc nitrogenous nucleus. In Nicotiana plants, most alkaloids are 3-pyridyl derivatives In cured leaf of Maryland Robinson Medium Broadleaf, 24 pyridine derivatives were identified, including nicotine, nomicotine, anabasine, oxynicotine, myosmine, 3-acetylpyridine, 2,3 -dipyridyl, iticotinamide, anatabine, nicotinic acid, and unidentified pyridine alkaloids of derivatives thereof (Tso 1990). Nicotine is the principal alkaloid in commercial tobacco (this was confirmed in 34 out of 65 Nicotiana species) nomicotine, rather than nicotine, appears to be the main alkaloid in 19 out of 65 species and anabasine is the third most important. In addition to the above-mentioned principal and minor alkaloids, the presence of many trace amounts of new alkaloids or their derivatives were frequently reported, including, for example, 2.4 -dipyridyl, 4,4 -dipyridyl, N -formylanabasine, A -formylanatabine, N -acetylanatabine, N -hexanoyl-nomicotine, N -octanoyl-nomicotine, T-(6-hydroxyoctanoyl) nomicotine, and l -(7-hydroxyoctanoyl) nor-nicotine. 

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