Tobacco – Tobacco treatment – With electrical or radiant energy
Reissue Patent
2001-05-22
2003-05-27
Colaianni, Michael (Department: 1731)
Tobacco
Tobacco treatment
With electrical or radiant energy
C131S294000, C131S295000, C131S290000, C131S347000, C204S158200, C204S158210, C204S157600
Reissue Patent
active
RE038123
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of treating tobacco to reduce the content of, or prevent formation of, harmful nitrosamines which are normally found in tobacco. The present invention also relates to tobacco products having low nitrosamine content.
BACKGROUND OF THE INVENTION
Others have described the use of microwave energy to dry agricultural products. Use of microwave energy to cure tobacco is disclosed in U.S. Pat. No. 4,430,806 to Hopkins. In U.S. Pat. No. 4,898,189, Wochnowski teaches the use of microwaves to treat green tobacco in order to control moisture content in preparation for storage or shipping. In U.S. Pat. No. 3,699,976, microwave energy is described to kill insect infestation of tobacco. Moreover, techniques using impregnation of tobacco with inert organic liquids (U.S. Pat. No. 4,821,747) for the purposes of extracting expanded organic materials by a sluicing means have been disclosed wherein the mixture was exposed to microwave energy. In another embodiment, microwave energy is disclosed as the drying mechanism of extruded tobacco-containing material (U.S. Pat. No. 4,874,000). In U.S. Pat. No. 3,773,055, Stungis discloses the use of microwave to dry and expand cigarettes made with wet tobacco.
Prior attempts to reduce tar and harmful carcinogenic nitrosamines primarily have included the use of filters in smoking tobacco. In addition, attempts have been made to use additives to block the effects of harmful carcinogens in tobacco. These efforts have failed to reduce the oncologic morbidity associated with tobacco use. It is known that fresh-cut, green tobacco has virtually no nitrosamine carcinogens. See, e.g., Wiernik et al, “Effect of Air-Curing on the Chemical Composition of Tobacco,” Recent Advances in Tobacco Science, Vol. 21, pp. 39 et seq., Symposium Proceedings 49th Meeting Tobacco Chemists' Research Conference, Sep. 24-27, 1995, Lexington, Ky. (hereinafter “Wiernik et al”). However, cured tobacco is known to contain a number of nitrosamines, including the harmful carcinogens N′-nitrosonornicotine (NNN) and 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK). It is widely accepted that such nitrosamines are formed post-harvest, during the curing process, as described further herein. Unfortunately, fresh-cut green tobacco is unsuitable for smoking or other consumption.
In 1993 and 1994, Burton et al at the University of Kentucky carried out certain experiments regarding tobacco-specific nitrosamines (TSNA), as reported in the Abstract, “Reduction of Nitrite-Nitrogen and Tobacco N′-Specific Nitrosamines In Air-Cured Tobacco By Elevating Drying Temperatures”, Agronomy & Phytopathology Joint Meeting, CORESTA, Oxford 1995. Burton et al reported that drying harvested tobacco leaves for 24 hours at 71° C., at various stages of air curing, including end of yellowing (EOY), EOY+3, EOY+5, etc. resulted in some reduction of nitrosamine levels. Reference is also made to freeze drying and microwaving of certain samples, without detail or results. Applicant has confirmed that in the actual work underlying this Abstract, carried out by Burton et al at the University of Kentucky, the microwave work was considered unsuccessful. Certain aspects of Burton et al's 1993-94 study are reported in Wiernik et al, supra, at pages 54-57, under the heading “Modified Air-Curing”. The Wiernik et al article postulates that subjecting tobacco leaf samples, taken at various stages of air-curing, to quick-drying at 70° C. for 24 hours, would remove excess water and reduce the growth of microorganisms; hence, nitrite and tobacco-specific nitrosamine (TSNA) accumulation would be avoided. In Table II at page 56, Wiernik et al includes some of Burton et al's summary data on lamina and midrib nitrite and TSNA contents in the KY160 and KY171 samples. Data from the freeze-drying and the quick-drying tests are included, but there is no mention of the microwaved samples. The article contains the following conclusion:
It can be concluded from this study that it may be possible to reduce nitrite levels and accumulation of TSNA in lamina and midrib by applying heat (70° C.) to dark tobacco after loss of cell integrity in the leaf. Drying the tobacco leaf quickly at this stage of curing reduces the microbial activity that occurs during slow curing at ambient temperature. It must be added, however, that such a treatment lowers the quality of the tobacco leaf.
Id. at page 56. The Weirnik et al article also discusses traditional curing of Skroniowski tobacco in Poland as an example of a 2-step curing procedure. The article states that the tobacco is first air-cured and, when the lamina is yellow or brownish, the tobacco is heated to 65° C. for two days in order to cure the stem. An analysis of tobacco produced in this manner showed that both the nitrite and the TSNA values were low, i.e., less than 10 micrograms per gram and 0.6-2.1 micrograms per grams, respectively. Weirnik et al theorized that these results were explainable due to the rapid heating which does not allow further bacterial growth. Weirnik et al also noted, however, that low nitrite and TSNA values, less than 15 micrograms per gram of nitrite and 0.2 microgram per gram of TSNA, were obtained for tobacco subjected to air-curing in Poland.
SUMMARY OF THE INVENTION
One object of the present invention is to substantially eliminate or reduce the content of nitrosamines in tobacco intended for smoking or consumption by other means.
Another object of the present invention is to reduce the carcinogenic potential of tobacco products, including cigarettes, cigars, chewing tobacco, snuff and tobacco-containing gum and lozenges.
Still another object of the present invention is to substantially eliminate or significantly reduce the amount of tobacco-specific nitrosamines, including N′-nitrosonornicotine (NNN), 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), N′-nitrosoanatabine (NAT) and N′-nitrosoanabasine (NAB), in such tobacco products.
Another object of the present invention is to treat uncured tobacco at an appropriate time post-harvest so as to arrest the curing process without adversely affecting the tobacco's suitability for human consumption.
Another object of the present invention is to reduce the content of tobacco-specific nitrosamines in fully cured tobacco.
The above and other objects and advantages in accordance with the present invention can be obtained by a process for reducing the amount of or preventing formation of nitrosamines in a harvested tobacco plant, comprising
subjecting at least a portion of the plant to microwave radiation, while said portion is uncured and in a state susceptible to having the amount of nitrosamines reduced or formation of nitrosamines arrested, for a sufficient time to reduce the amount of or substantially prevent formation of at least one nitrosamine.
It is preferred that in the process of the invention, the step of subjecting to microwave radiation is carried out on a tobacco leaf or portion thereof after onset of yellowing in the leaf and prior to substantial accumulation of tobacco-specific nitrosamines in the leaf.
It is also preferred that in the process of the invention, the step of subjecting to microwave radiation is carried out prior to substantial loss of the leaf's cellular integrity.
In additional preferred embodiments of the process, the tobacco is flue tobacco and the step of subjecting to microwave radiation is carried out within about 24 to about 72 hours post-harvest, even more preferably within about 24 to about 36 hours post-harvest.
In still other embodiments of the process, the harvested tobacco is maintained under above-ambient temperature conditions in a controlled environment prior to the step of subjecting to microwave radiation.
Preferred aspects of the process include a step, prior to subjecting a tobacco leaf which preferably includes the stem to microwave radiation, of physically pressing the leaf to squeeze excess moisture therefrom, to ensure more uniform dryin
Banner & Witcoff , Ltd.
Colaianni Michael
Regent Court Technologies, LLC.
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