BG65186B1 - Method for tobacco processing for reducing the content of nitrosamines and products turned out by this method - Google Patents

Abstract

The method finds application in the tobacco industry. The products turned out by it are used for the manufacture of cigarettes, cigars, chewing tobacco, tobacco for snuffing, for tobacco chewing gumsor toffees. The method includes subjecting at least part of the tobacco plant to microwave irradiation or irradiation with higher frequency at a suitable moment during its drying whilst it is in a state allowing the reduction of the content of nitrosamines specific for the tobacco including N'-nitrosonornicotine, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanon, N-nitrosoantabine and N'-nitrosoanabasin, other cancerogens, or retention, or prevention of their formation. The turned out products have lower or insignificant content of these substances in comparison with the products dried by the traditional methods. The irradiation of the tobacco leaves is made after the commencement of their yellowing or before the accumulation in them of considerable quantities of nitrosamines specific for the tobacco for a time sufficient for their effective drying without any parching. Irradiations from the distant infrared region, from the infrared region, from the ultraviolet region, soft X-rays or lasers, beams of electrons and gamma irradiation can be used as alternative sources of irradiation.

Description

The present invention relates to a method of processing tobacco to reduce the content of harmful nitrosamines or prevent their formation. The invention also relates to tobacco products low in nitrosamines.

BACKGROUND OF THE INVENTION

The use of microwave energy for drying agricultural products is known. US Patent 4 430 806 to Hopkins describes the use of microwave energy for tobacco drying. Wochnowski U.S. Patent No. 4,898,189 discloses microwave treatments for green tobacco in order to regulate the moisture content required for storage or transportation. US Pat. No. 3,699,976 describes the use of microwave energy for the destruction of insects in tobacco. Moreover, methods using tobacco impregnation with inert organic liquids (U.S. Pat. No. 4,821,747) for the extraction of present organic materials by washing agents are known, treating the mixture with microwave energy. In another embodiment, microwave energy is used to dry tobacco-derived materials — US $ 4,874,000. Stungis discloses US 3 773 055 for microwave irradiation for drying and increasing the volume of cigarettes prepared from moist tobacco.

Previous attempts to reduce the tar content and harmful carcinogenic nitrosamines in smoking tobacco have used filters. To block the effects of harmful carcinogens in tobacco, attempts have been made to use additives. These efforts do not result in the reduction of cancer-related cancers associated with tobacco use. Freshly sliced green tobacco is known to contain no carcinogenic nitrosamines, see, for example, Wiemik 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 49 ^{th Meeting Tobacco Chemists' Research Conference,} Sept. 24-27, 1995, Lexington, Kentucky, hereinafter referred to as Wiernik et al. It is also known that dried tobacco contains various nitrosamines, including the harmful carcinogens N'-nitrosonornicotine (NNN) and 4 (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK). It is recognized that these nitrosamines are subsequently formed during drying, as described below. Unfortunately, freshly cut green tobacco is unsuitable for smoking or other consumption.

As reported in the article "Reduction of Nitrite-Nitrogen and Tobacco N'-Specific Nitrosamines in Air-Cured Tobacco by Elevating Drying Temperatures", Agronomy & Phytopathology Joint Meeting, CORESTA, Oxford 1995, 1993 and 1994. Burton et al. from the University of Kentucky are conducting some experiments on tobacco-specific nitrosamines (TSNA). They reported that drying air on harvested tobacco leaves for 24 hours at 71 ° C at various drying stages, including at the end of yellowing, resulted in a decrease in the amount of nitrosamines. Low-temperature drying and microwave treatment of some samples without details or results are also mentioned. The applicant confirms that the actual work done by Burton et al. at the University of Kentucky, which underlies this essay, was unsuccessful. Some aspects of the study by Burton et al. 1993-1994 are cited in the work of Wiemik et al., pages 54 to 57 under the heading "Modified Air-Curing", where it is understood that the sampling of tobacco leaves taken at different stages of drying with air, accelerated drying at 70 ° C for 24 h would eliminate excess water and reduce the multiplication of microorganisms, avoiding the accumulation of nitrites and tobacco-specific nitrosamines (TSNA). In Table II on page 56 Wiemik et al. some data on the content of nitrites and TSNA in the leaf part and in the veins for samples KY 160 and KY171 are shown. Data from low temperature and accelerated drying tests are also shown, but no mention is made of samples subjected to microwave treatment. The following conclusion is reached in the article:

"From the study, it can be concluded that it is possible to reduce the nitrite content and accumulation of TSNA in leaf and veins by heating darkened tobacco (70 ° C) after destroying the integrity of leaf cells. At this stage, the rapid drying of the tobacco leaves reduces the microbial activity that is experienced by slow drying at ambient temperature. It should be added that this treatment impairs the quality of the tobacco leaves. "

As an example of two-step drying, the article also discusses the traditional method of drying Skroniowsky tobacco in Poland, in which the tobacco is first air-dried and when the leaves turn yellow or the brown color reaches a temperature of 65 ° C to dry the veins. The analysis of tobacco thus obtained shows that the nitrite and TSNA content is low, i. E. respectively less than 10 microg / g and 0.6-2.1 microg / g. Wiemik et al theoretically conclude that these results can be explained by rapid heating, which does not allow for rapid bacterial propagation. It is also noted that for air-dried tobacco, low nitrite values of less than 15 microg and TSNA of less than 0.2 microg were achieved in Poland.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method of processing tobacco for smoking or for consumption by other means, in which the content of nitrosamines is reduced or substantially eliminated.

Another object of the invention is to reduce the carcinogenic risk of tobacco products, including cigarettes, cigars, chewing tobacco, snuff, tobacco chewing gum and candy.

Another object of the invention is to substantially reduce the amount of tobacco-specific nitrosamines including N'-nitrosonornicotin (NNN) and 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK), N'- nitrozoanabatin (NAT) and N'-nitrozoanabasin (NAB) or substantially eliminate their content in these tobacco products.

It is another object of the invention to provide a method of treating non-dried tobacco at an appropriate time after harvesting so as to maintain the drying process without impairing the usability of the tobacco.

It is another object of the invention to reduce the content of tobacco-specific nitrosamines in fully dried tobacco.

Another aim is to provide a consumer-friendly tobacco product that contains a substantially reduced amount of tobacco-specific nitrosamines, which results in a reduced content of NNNs and NNKs and their metabolites in particular, which uses tobacco in various forms, such as tobacco. this reduces the carcinogenic risk. The tobacco product may be cigarettes, cigars, chewing tobacco, snuff, tobacco chewing gum or candy.

These and other objects and advantages of the present invention are achieved according to a method of reducing the content of nitrosamines or preventing their formation in a harvested tobacco plant, the method comprising the following steps:

subjecting at least a portion of the tobacco plant to high frequency irradiation for a fixed period of time, using the radiation method according to the method while the portion is dry, the yellow and tobacco leaves of the plant are in the yellowing stage before becoming brown and before substantial destruction of the cell integrity occurs, which allows the formation of the same nitrosamines to be blocked. According to the invention, the irradiation administration time is sufficient to prevent substantially the formation of at least one nitrosamine.

According to the invention, the high frequency irradiation is microwave and is applied to the tobacco leaf or part thereof after the leaf yellowing begins and before the tobacco specific nitrosamines are accumulated, the tobacco leaves or parts thereof being arranged in a layer with a thickness of one leaf.

In addition, according to the method prior to irradiation, the tobacco plants are pre-removed with leaf stalks and pressed to remove excess moisture or treated with steam.

The method is also applicable to tobacco plants with handles pre-pressed to remove excess moisture or treated with steam before irradiation.

Furthermore, according to the invention, high frequency radiation is at a frequency higher than the microwave regions of the electromagnetic spectrum.

The method is also applicable to tube-dried tobacco plants, irradiation being carried out over a period of 24 hours to about 72 hours after harvesting, irradiation being performed for at least 1 s at a predetermined power.

According to the method, drying is carried out after the irradiation step.

In addition, irradiation can be accomplished with a laser beam or an electron beam generated by an electron accelerator (gamma radiation).

It is also possible that the applied radiation has a higher frequency and a shorter wavelength than the microwave region of the electromagnetic spectrum.

The invention also relates to a tobacco product obtained by the said method, which product contains dried non-green or yellow edible Virginia tobacco for essentially tubeless drying, used to extract bulk organic materials, and which product has a total content of N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N'-nitrozoanabasin less than 0.2 µg / g.

It is possible that the total content of N'nitrozonornicotin, 4- (N-nitrosomethylamino) -1 (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N'nitrozoanabasin is 0.05 µg / g or less, such as dried non-green or yellow tobacco was selected from the group containing Virginia tubing and Burley varieties.

In another embodiment, the tobacco product containing dried non-green or yellow edible Virginia tobacco for tubular leaf drying has a total content of N'-nitrosonornicotin, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1 -butanone, N'-nitrosoanatabine and N'-nitrosoanabasin less than 0.2 µg / g.

It is also possible that the total content of N'nitrozonornicotin, 4- (N-nitrosomethylamino) -1 (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N'nitrozoanabasin may be 0.05 µg / g or less, such as dried non-green or yellow tobacco is selected from the group consisting of Virginia tubing and Burley varieties.

According to the invention, the tobacco product, including dried non-green or yellow, edible tobacco free of organic liquids used to extract bulk organic materials, contains 4- (No. nitrosomethylamino) -1- (3-pyridyl) 1-butanone 0.002 microg / g or less.

In another embodiment of the invention, the tobacco product, including dried non-green or yellow edible tobacco in leaf form, contains 4-O-nitrosomethylamino) -1- (3-pyridyl) -1-butanone 0.002 microg / g or more less, these values may also be 0.001 microg / g or less.

According to the invention, the dried non-green or yellow tobacco is a Virginia tubing or Burley variety.

In the tobacco product obtained according to the invention, the total content of N'-nitrosonornicotine, 4- (N-nitrosomethylamino) 1- (3-pyridyl) -1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasin is 0.15 microg / g or more less or 0.1 microg / g or less.

In addition, the tobacco product of the invention contains at least one tobacco-specific nitrosamine selected from the group consisting of N'-nitrosonornicotine, 4- (Ν-ΗΗτροzomethylamino) -1- (3-pyridyl) -1-butanone, N'nitrozoanabatin and N ' -Nitrozoanabasins whose content is at least about 75 wt% lower than the content of the same tobacco-specific nitrosamine in dried brown tobacco of the same crop as that of dried non-green or yellow tobacco but which has been traditionally dried in the absence of brown tobacco at least one content reduction step n specific nitrosamine tobacco.

In addition, the content of at least one tobacco-specific nitrosamine is at least about 90% or 95% less than the content of the same tobacco-specific nitrosamine in dried brown tobacco of the same crop, but which brown tobacco has traditionally been dried at the absence of steps to reduce the content of at least one tobacco-specific nitrosamine.

According to the present invention, microwave irradiation is applied to the sheet or part of it for a time sufficient to effectively dry it without being burnt so that it is suitable for consumption.

In preferred embodiments, the non-green tobacco product has a TSNA content (NNN, NNK, NAB and NAT) of less than 0.2 µg / g, preferably less than 0.15 µg / g, and more preferably less than 0.1 microg / g; an NNN content of less than 0.15 µg / g, preferably less than 0.10 µg / g, and even more preferably less than 0.05 µg / g; and an NNK content of less than 0.002 [mu] g / g, preferably less than 0.001 [mu] g / g, and more preferably less than 0.0005 [mu] g / g.

In other embodiments, the non-green or yellow tobacco product contains non-green or yellow tobacco suitable for consumption that has a TSNA content (NNN, NNK, NAB and NAT) of about 25% by weight.

In other embodiments of the invention, the non-green or yellow tobacco product contains non-green or yellow tobacco suitable for consumption that has a TSNA content (NNN, NNK, NAB and NAT) of at least about 75% by weight, preferably at least about 90 t , preferably at least about 95% by weight, and most preferably at least about 99% by weight, by weight of these substances in a tobacco product of the same variety produced from the same crop as the product of the invention, but which is dried without microwave irradiation or without the use of other methods of reducing the nitrosamines content. Preferably this non-green or yellow tobacco product contains non-green or yellow tobacco suitable for consumption that contains at least one TSNA selected from the group of NNN, NNK, NAB and NAT weighing at least about 75% by weight, preferably at least about 90% wt.%, preferably at least about 95 wt.%, and preferably at least about 99 wt.% less than the weight of the corresponding substance in a tobacco product of the same type produced from the same crop as the product of the invention but which is dried without microwave irradiation or without the use of other methods of reducing nitroxide content ins.

Brief description of the attached figures

Figure 1 shows a photograph illustrating a tubular dried "Virginia" yellow tobacco when it has passed from 24 to 72 hours after harvest.

Figure 2 shows a photograph illustrating microwave irradiation of tubular dried "Virginia" low tobacco nitrosamines according to the invention.

Figure 3 is a side elevational perspective view of an industrial type mobile device by which the treatment of the present invention can be carried out.

Detailed description of the invention

It could be said that tobacco drying is more of an art than a science, since every drying condition must be chosen to take into account factors such as differences in varieties, differences in harvested leaves, depending on their position. on the stem, different drying parameters, changes in atmospheric conditions during one season or different seasons during such drying. For example, the optimum condition for tube drying is determined empirically by specialists who have gained experience over a considerable period of time. See, for example, Peele et al., “Chemical and Biochemical Changes during the Flue Curing of Tobacco,” Recent Advances in Tobacco Science, Vol. 21, pp. 81 et seq., Symposium Proceedings 49 ^{th Meeting Chemists' Research Conference, September} 24-27,1995, Lexington, Kentucky ( hereafter referred to as "Peele et al"). Therefore, one skilled in the art of tobacco drying would appreciate that the other parameters of the present invention within its broadest range vary to some extent, depending on the accurate consideration of the above factors for a particular type of harvested tobacco.

According to a preferred embodiment of the present invention, it is found that during drying there is an interval during which the tobacco can be processed to prevent the formation of TSNA. Of course, the precise determination of this interval during which TSNA formation can be effectively prevented or substantially reduced depends on the type of tobacco, the method of drying, and various other factors, including those mentioned above. .

According to a preferred embodiment of the present invention, this interval corresponds to the time when the collected tobacco stayed for some time and the tobacco leaf far after the state of "freshly sliced" or "green", but before substantial accumulation of TSNA or nitrites in the leaf. Usually, this time interval corresponds to the time during which the leaf is in the yellowing stage before it turns brown and before the essential destruction of the cell integrity. The terms "substantially" and "substantially" used in the description generally denote a dominant or greater part in a conditional "presence or absence" scale. During this time interval, the formation of nitrosamines can be substantially prevented or the content of already formed ones can be substantially reduced by subjecting the microwave irradiated tobacco to a specified power for a specified time, as explained below. This microwave treatment essentially prevents the natural formation of TSNA and makes it possible to obtain an edible, dry golden yellow leaf. If substantial accumulation of TSNA has started, usually in the final yellowing phase, microwave treatment of the leaves according to the invention substantially retains the natural cycle of their formation and prevents their further formation. With such treatment of yellow or yellowing tobacco for optimum drying time, the resulting tobacco product has a TSNA level substantially similar to that of freshly harvested green tobacco, retaining its aroma and taste.

Another embodiment of the invention relates to the treatment of dried (brown) tobacco to effectively reduce the content of TSNA in it, the dried tobacco being re-hydrated and then subjected to microwave irradiation, as explained below.

The present invention is applicable to the treatment of harvested tobacco leaves for consumption. Much research has been done on tobacco, in particular tobacco-specific nitrosamines. Freshly harvested tobacco leaves are called "green tobacco" and do not contain known carcinogens, but this tobacco is not suitable for consumption. Drying green tobacco depends on its type. For example, the Virginia variety of light is usually tubular dried, while the Burley and some dark varieties are air-dried. Usually, pipe drying takes five to seven days, while air drying takes more than two months. As indicated by Peele et al, tube drying generally involves three steps: yellowing (35 ° C - 40 ° C) for about 36 to 72 hours, although yellowing has been reported to start earlier than 36 hours, e.g. for some Virginia varieties, 24 h; step of drying the leaves (40 ° C - 57 ° C) for 48 h and drying the medium veins (handle) at temperature (57 ° C - 75 ° C) for 48 h. During yellowing, many significant chemical and biochemical changes begin, which continue even during the initial phases of leaf drying.

In a typical tube-drying process, the yellowing step is carried out in ovens under natural climatic conditions, whereby the green leaves gradually lose their color due to chlorophyll decay, yielding corresponding yellow carotene pigments. According to an article by Peele et al, tube-dried tobacco is yellowed when the outside air vents of the oven are closed and maintained at a temperature of about 35 ° C to 37 ° C. This process is carried out under regulated conditions, maintaining the relative humidity in the oven at approximately 85% by weight to limit the moisture loss in the leaves and continuing the metabolic processes that began in the field. The operator monitors the drying process first and foremost by observing the loss of chlorophyll and green from the leaves and the transition to the desired lemon-yellow to golden-orange color.

In one Virginia-type tubular dried tobacco, in which the test is carried out as described herein, freshly harvested green tobacco is placed in an oven for about 24 48 h at a temperature of about 100-110 ° F (37.8 ° C - 43 , 3 ° C) until the leaves turn more or less entirely yellow (see Figure 1). Yellow tobacco has a reduced moisture content, ie from about 90 wt% for green tobacco to about 70 wt% - 40 wt% for yellow tobacco. At this stage, yellow tobacco is essentially free of carcinogens, with the TSNA content being the same as that of freshly cut green tobacco. This Virginia tobacco stays in the yellowing stage for about 6-7 days, after which the leaves turn brown. Typically, Virginia Virginia tobacco has a moisture content of 11% to about 15%. The conversion of tobacco from yellow to brown leads to the formation and substantial accumulation of nitrosamines and increased microbial content. The exact mechanism by which tobacco-specific nitrosamines are formed is unclear, but is thought to be favored by microbial activity due to the involvement of microbial nitrite reductases in the generation of nitrites during drying.

Tobacco-specific nitrosamines are thought to be formed by the reaction of amines with nitrosating nitrite derivatives such as NO ₂ , N ₂ O ₃ and N ₂ O ₄ in acidic media. Wiemik et al discuss the accepted way of forming the TSNA on pages 43 - 45, from which a brief summary is provided below.

Tobacco leaves contain an abundance of amines in the form of amino acids, proteins and alkaloids. The tertiary amine nicotine (referred to in the formula below is (1)) is the major alkaloid in tobacco, while the other nicotine alkaloids are the secondary amino nornicotine (2), anatabine (3) and anabazine (4). Tobacco generally contains up to 5% by weight of nitrates and traces of nitrites.

Nitrosation of nornicotine (2), anatabine (3) and anabazine (4) yields the corresponding nitrosamines: N′-nitrosonornicotine (NNN, 5), N′-nitrozoanatabine (NAT, 6) and N′-nitrozoanabazine (NAB, 7). Nitrosation of nicotine (1) in aqueous solution results in a mixture of 4 (N'-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK, 8), (NNN, 5) and 4- (L- nitrosomethylamino) -4- (3-pyridyl) -1-butanal (NNA, 9). Less common nitrosamines include NNAL (4-N-nitrosomethylamino) -1- (3-pyridyl) -1-butanol, 10), iso-NNAL (4-1M-nitrosomethylamino) 1- (3-pyridyl) -1-butanol, 11 ) and iso-NNAC (4- (N-nitrosomethylamino) -4- (3-pyridyl) -butyric acid 12). The formation of these TSNAs from the respective tobacco alkaloids is shown schematically below using the accepted designations 1 to 12 (reproduced by Wiemik et al, p. 44).

stunned

VH, Ν · ΝΟ

It is now generally accepted that green freshly harvested tobacco does not actually contain nitrite or TSNA, and these ingredients are formed by drying or storing tobacco. In the last decade, studies have been conducted in an attempt to determine the circumstances surrounding the formation of TSNA during tobacco drying. Several important factors have been identified, including the genotype of the plant, the maturity of the plant when harvesting the leaves, drying conditions, and microbial activity.

Studies have shown that nitrites and TSNA accumulate upon drying with air in the interval after the end of yellowing until the leaves turn completely brown, ie. 2-3 weeks after picking the leaves for certain varieties subjected to ordinary air drying, and approximately one week after picking for varieties subjected to tube drying. This is the time during which cell integrity is destroyed due to loss of moisture, as the cell content goes into the intercellular space. Therefore, air drying has a short time during which the cells are disintegrated and there is an opportunity to feed the microorganisms. Wiernik et al suggest that then, as a result of dissimilatory nitrate reduction, nitrite accumulation can become significant, thereby making TSNA possible.

There are few publications on the effects of microbial flora on tobacco leaves during growth and on drying, as cited by Wiernik et al., But the involvement of microbial nitrate reductases in the generation of nitrates during drying is suggested. When, after the yellowing phase, the cellular structure is destroyed, the nutrient medium becomes accessible to the entry of microorganisms capable of producing nitrites under favorable conditions, i. high humidity, optimum temperature and complete lack of oxygen. Usually this is a very short time interval during which the water activity is high enough and the cellular structure is deintegrated.

According to the present invention, the formation of TSNA in tobacco is prevented or delayed by subjecting the collected tobacco leaves to microwave irradiation under the conditions described herein. According to a preferred embodiment, the tobacco leaves are subjected to microwave irradiation for the time from the onset of yellowing to the onset of substantial destruction of cellular integrity. For optimum results, it is preferable to feed the collected leaves one at a time into the microwave field rather than to piles or bales. Treatment of the leaves in this manner has wholly or substantially prevented the formation of tobacco-specific nitrosamines, including the known carcinogens NNN and NNK.

In accordance with preferred embodiments of the present invention, non-green and / or yellow tobacco products which are suitable for consumption and which have a lower content of at least one tobacco-specific nitrosamine than tobacco dried by the conventional method can be obtained. Usually green or freshly cut tobacco is not fit for consumption, as noted above. The term "non-green" means tobacco that has lost at least a large portion of chlorophyll, and contains yellow leaves, wholly yellowed leaves, and leaves that turn brown in places. In preferred embodiments, non-green tobacco contains a TSNA (NNN, NNK, NAB and NAT) of less than 0.2 microg / g, preferably less than 0.15 microg / g, better than 0.1 microg / g; the NNN content is less than 0.15 µg / g, preferably less than 0.10 µg / g, preferably less than 0.05 µg / g; an NNK content of less than 0.002 microg / g, preferably less than 0.001 microg / g, more preferably less than 0.0005 microg / g. As noted above, given a number of factors that may influence the formation of TSNA in tobacco, one of ordinary skill in the art would appreciate that the number is not absolute, but rather the scope.

The present invention also relates to a tobacco product containing dried yellow tobacco that is suitable for consumption and which has a lower content of at least one tobacco-specific nitrosamine than conventional dried tobacco. In preferred embodiments, the yellow tobacco product comprises TSNA (NNN, NNK, NAB and NAT), of NNN and of NNK within the abovementioned limits.

In other embodiments, the non-green or yellow tobacco product contains non-green or yellow tobacco suitable for consumption that has a TSNA content (NNN, NNK, NAB and NAT), which is about 25% by weight of these substances in fresh harvested green tobacco from which this product is made. Preferably this non-green or yellow tobacco product has a TSNA content of about 10 wt.% By weight, another preferred content is about 5 wt.%, And it is best to be substantially close to the TSNA content of the freshly harvested tobacco from which is produced (for example up to several percent by weight). For example, according to the present invention, products having a TSNA content may be obtained within the abovementioned limits, whereas, in typically dried tobacco of the same crop, there are normally many times greater amounts of TSNA than in freshly cut tobacco. According to the present invention, the low content of nitrosamines present in freshly cut tobacco is maintained. In addition, the non-green or yellow tobacco product according to the invention contains non-green or yellow tobacco suitable for consumption that contains 25% by weight of at least one TSNA selected from NNN, NNK, NAB and NAT, preferably 10% by weight, according to another a preferred embodiment is 5% by weight, and preferably has a content substantially close to that of the corresponding TSNA or nitrosamines in the freshly harvested tobacco from which the product is produced (eg in amounts up to several weight percent). In other words, the content of, for example, the NNN in tobacco according to the invention is within the abovementioned limits, which is the amount of NNN in the freshly cut green tobacco, and the content of NNN + NNK in the tobacco according to the invention is within the abovementioned amounts, which is of NNN + NNK in freshly cut green tobacco, etc. These comparisons were made by analyzing freshly sliced green tobacco for TSNA content up to 24 h after harvest.

According to other embodiments of the invention, the non-green or yellow tobacco product contains a non-green or yellow tobacco having a TSNA content (NNN, NNK, NAB and NAT) of at least about 75%, preferably at least about 90, by weight. preferably at least about 95% by weight, and most preferably at least about 99% by weight by weight of these substances in a tobacco product of the same variety produced from the same crop as the product of the invention but which is dried without microwave irradiation or without the use of other methods of reducing the content of nitrosamines. Preferably this non-green or yellow tobacco product contains non-green or yellow tobacco suitable for consumption that contains at least one TSNA selected from the group of NNN, NNK, NAB and NAT weighing at least about 75% by weight, preferably at least about 90% wt.%, preferably at least about 95 wt.%, and most preferably at least about 99 wt.% less than the weight of the substance in a tobacco product of the same type (eg when comparing a cigarette with another cigarette) produced of the same crop as the product of the invention but which is dried without microwave irradiation or without the application of another methods for reducing the content of nitrosamines. In these embodiments, weight comparisons of TSNA were made for a cigarette made from yellow tobacco dried according to the invention and a cigarette made from tobacco of the same crop but dried by conventional methods without microwave irradiation.

The yellowing stage during which the tobacco leaf is subjected to microwave irradiation can generally be determined in one of the following ways: (a) by examining the color of the leaf when the green color turns substantially yellow; (b) by measuring the percentage conversion of chlorophyll to sugars; (c) by observing the onset of nitrite or nitrosamines formation, which usually coincides with the end of the yellowing stage; or (d) by measuring the moisture content of the leaves, for example when they have a moisture content of 40% to about 70%. If green tobacco is subjected to microwave irradiation, no inhibition of the formation of nitrosamines or retention of their formation is observed. But when microwave energy is applied after the onset of yellowing or before loss of cellular integrity or after substantial accumulation of TSNA in the leaf, the observed decrease in the amount of nitrosamines or prevent their formation is categorical and unexpected, as shown by the data commented on. -down.

The optimum time to subject a harvested microwave tobacco to tobacco during yellowing varies and depends on a number of factors, including differences in varieties, climatic conditions, etc. Therefore, one skilled in the art would be able to determine the optimum microwave treatment time for each tobacco variety in the time interval from the onset of yellowing (determined, for example, by the loss of the predominant green color of the leaf) to the time at which the leaf loses substantially cellular integrity (including brown). For example, to determine for a genotype the relative time in the drying cycle at which significant accumulation of TSNA begins, or to determine the transient phase of cellular integrity loss, leaf samples can be tested using the measurement procedures described herein. of nitrite content or TSNA. Just as subjecting the leaves to microwave irradiation before significant accumulation of TSNA is the most preferred form of the process according to the invention, so the principles of the invention can also be applied to tobacco leaves that are in the process of formation and have already accumulated significant amounts of TSNA. When microwave irradiation is applied at this stage, effective inhibition of the further formation of tobacco-specific nitrosamines TSNA is achieved. However, when the leaves are completely dried, the TSNA level is substantially stabilized and microwave irradiation is ineffective in reducing their content, except under rehydration conditions, as described below.

Upon microwave irradiation according to the invention, the tobacco leaf has a reduced moisture content of less than 10% by weight, often approximately 5% by weight. If desired, before the production of tobacco products, such as cigarettes, the tobacco leaf can be rehydrated to the normal moisture content for brown dried tobacco, for example, about 11 wt.% -15 wt.% For tube-dried Virginia tobacco.

The present invention is applicable to all tobacco varieties, including those under tubular drying logs, light varieties, Burley varieties, dark varieties, Oriental tobacco, etc. Following the guidance given herein, one skilled in the art would be able to determine the most effective period during drying in order to apply the microwave irradiation step to achieve the objectives and advantages of the invention.

According to preferred aspects of the process, prior to microwave irradiation, the tobacco leaf, usually with a handle and veins, is mechanically pressed to remove excess moisture and to ensure a more even drying in the microwave. This step is usually accomplished as before the insertion into the chamber of the microwave device, the sheet passes through a pair of rotating cylindrical rollers spaced at a suitable distance from each other. This compression helps to squeeze out moisture from the handle, to a lesser extent than the midrib and larger ones, resulting in a better and more evenly dried product. The rolls can be made of solid rubber, plastic or steel and can be of the selected length. Preferably, they can be spaced 1/8 to 1/4 (0.3175 cm to 0.635 cm) apart, but the distance is chosen to accommodate the thickness of one sheet, which may be different. The rollers can be driven by belt or chain drive with a suitably selected motor. As will be apparent to one skilled in the art, in addition to rotating rollers, other methods of squeezing or pressing may be used to obtain the same result.

The preferred embodiment for pressing the leaves described above allows for greater productivity since no cutting of the handles is necessary and may reduce the time for microwave irradiation. This embodiment is particularly suitable for tobacco leaves, which are made of cigarettes, which typically contain a certain amount of handles as part of the tobacco mixture. Of course, the compression step can be removed when the leaf handle is cut and discarded.

In another preferred embodiment, prior to microwave irradiation, the leaves are treated with steam instead of compressing or cutting the handles. As with the pressing step, steam treatment of the whole leaves, including the handles, is carried out in order to obtain a more even distribution of moisture in the handles and larger veins, which in turn results in a more even drying of the the whole sheet in microwave irradiation. As a result of applying this method, whole leaves, including handles, can be used in tobacco products. Although a detailed embodiment would be obvious to one skilled in the art, successful results can be obtained when the leaves are placed in a suitable steam container for a time sufficient to allow them to become soft and supple to a degree, typically of about 30 s. , up to about 5 min.

The principles of the present invention can also be applied to brown and already dried tobacco that has been re-hydrated. In cases where re-hydrated brown tobacco is subjected to microwave irradiation, there is a significant and unexpected decrease in the content of TSNA, in particular NNN and NNK, but these results are not as impressive as in the case of the invention applied to unripe yellow tobacco before substantial amounts of TSNA or nitrites have accumulated in the leaves. However, adding moisture to the dried leaves, for example by spraying with enough water to moisten them effectively, followed by microwave irradiation of the re-hydrated leaves, reduces the content of TSNA, as shown in the following examples.

As noted above, microwave treatment of dried or brown tobacco alone has little effect on nitrosamines content. Re-hydration of the dried tobacco leaves prior to irradiation has been found to contribute to the reduction of nitrosamines content. In one preferred embodiment, the dried tobacco product is rehydrated by directly adding to the leaves an appropriate amount of water, typically at least about 10% by weight, to maximize absorption. Exposing the re-hydrated sheets to microwave irradiation as described in the non-dried tobacco way results in a decrease in the nitrosamines content, which is shown below. The leaves can be moistened in any suitable way. If the dried tobacco is not in separate sheets, for example in the form of a whole "restored" sheet, it can be re-hydrated in a similar way, for example by 10 wt% to 70 wt% water, and then subjected to microwave irradiation . Depending on the degree to which the leaves are moistened, the appropriate irradiation conditions and parameters are also chosen, but they are usually within the limits of yellow tobacco treatment cited above.

According to the present invention, in the microwave treatment of re-hydrated brown tobacco, the content of TSNA (NNN, NNK, NAB and NAT), measured separately or in total, is reduced by at least 25% by weight, preferably by about 35%, and even more well, at least about 50% by weight of these substances in the dried brown tobacco before re-hydrating.

As used herein, the term "microwave radiation" means electromagnetic energy in the form of microwaves with frequency and wavelength falling within the microwave region. The term "microwave" generally defines that part of the electromagnetic spectrum that lies between the far infrared region and the ordinary radio frequency spectrum. The microwave range is located between a wavelength of approximately 1 mm and a frequency of 300,000 MHz to a wavelength of 30 cm and a frequency of less than about 1000 MHz. According to the present invention, high power microwaves are preferably used, generally at the lower end of this frequency range. In this preferred frequency range, there is a fundamental difference between microwave heating processes and in the classical way, such as infrared heating, for example when cooking. Due to the greater penetration, microwaves tend to heat up to a few centimeters in depth, while infrared heating is much more superficial. In the US, commercially available microwave devices, such as kitchen microwave ovens, operate at standard frequencies of 915 MHz and 2 450 MHz. These are also the standard industrial frequencies. In Europe, frequencies of 2 450 MHz and 896 MHz are commonly used. Of course, the objectives and advantages of the present invention may also be achieved by microwaves of other frequencies and wavelengths, with due regard for the conditions.

Depending on the desired application, microwave energy of different power can be generated. Typically, microwaves are manufactured from a 600 W to 1000 W microwave magnet for conventional kitchen microwaves (typically 800 W) to several hundred kilowatts for industrial appliances, most often by adding a 1 kW modular source. The magnetron can generate pulsed or continuous waves at a suitably high frequency.

The microwave device (or dryer) requires the connection between the microwave generator and the heated material. For the purposes of the present invention, any such device may be used insofar as it is adapted for the effective irradiation of the tobacco plant. The microwave device must be compatible with the microwave generator to optimize power transmission and avoid energy wastage. When the specimens are large, tumble dryers with multiple modes with dimensions several times larger than wavelengths are appropriate. To ensure the sheet is evenly heated to the device, there may be a so-called mode stirrer, a movable metal device that continuously changes the field distribution, and a moving surface, such as a conveyor belt. Best results are obtained by microwave irradiation of tobacco material with a single sheet thickness instead of piles or bales.

In preferred embodiments of the invention, microwave irradiation conditions for kitchen-type devices are: microwave frequencies from about 900 MHz to about 2,500 MHz, preferably from about 915 MHz to about 2450 MHz, and power from about 600 W to 300 kW, for preferably from 600 W to 1 000 W, and for industrial multimode devices from 2 kW to 75 kW, preferably from 5 kW to 50 kW. The heating time is at least one second, usually from 10 s to about 5 min. For the treatment of single sheets (not piles or bales) at a power of 800 W to 1000 W it is from 1 min to about 2.5 min. For high-power industrial microwave heating, for example, new high-power devices, for example in the range of 2 to 75 kW, are shorter - from 5 s to about 60 s, usually between 10 s and 30 s at 50 kW, with leaves once again thickness, not piles or bales. Of course, given the volume of the camera, the power and the amount of moisture in the leaves, one skilled in the art could determine the optimum field intensity for each microwave device. Generally speaking, using more power would require less time to microwave the leaves.

The conditions described above are not absolute and given the principles and methods of the present invention, one skilled in the art would be able to determine the appropriate microwave irradiation parameters. It shall be applied to or on a part of the leaf for a period sufficient to allow it to be effectively dried without burning the leaf so that it is fit for consumption. In addition, microwave irradiation is preferably applied to a sheet or part of it for a time and power that is sufficient to reduce the moisture content below 20%, preferably less than 10%.

Figure 3 is a side perspective view of an industrial type mobile device. Specifically, a Microdry microwave drying system of 300 kW of tobacco 1 is shown, which includes a mobile platform 2 (right front not shown), a conveyor microwave dryer 3, in the interior of which there are four modular chambers with a single wall structure (which can be made from aluminum grade 30003H14). Each chamber is approximately 16 (40.64 cm) long, 84 (213.36 cm) wide, and 48 (121.92 cm) high, and has four access doors, two on each wall, the doors being locked double, to avoid accidental exposure to microwave radiation.

Figure 3 also shows an automatic cutting mechanism 5 having a plurality of rotating blades to remove the leaf handles 4. The cutting mechanism may be a straight strip approximately 3.4 (8.636 cm) wide, pointing downward towards the center of the leaf, which are submitted manually. A remedy may also be provided to protect the operator's hands from possible injury. Although the figure depicts a cutting mechanism for removing the handles, in accordance with other embodiments of the invention, whole leaves can be used as indicated above. For this purpose, a container with steam or a pair of rollers can be fitted in place of the cutting mechanism to remove moisture from the leaves by pressing.

As shown in Figure 3, the leaves with cut handles 6 are fed through a belt conveyor 7 to the main microwave dryer 3 with four chambers. According to one embodiment of the invention, the length of the dryer in this system is about 78 feet (23.77 m). The conveyor system may have several belts at different speeds, such as polypropylene belts, arranged in such a way as to allow the material to be brought into the dryer and to remove it from the conveyor, so that the cut handles fall between the pairs of belts and fall on the receiver below the belts. (not shown). The tapes then transfer the tobacco leaves without handle through one of the two traps located in each second chamber in order to retain microwave energy, and then to a selected chamber where each sheet is microwave irradiated according to the principles of the invention described above. The conveyor then transports the leaves through the outlet of the chamber and through the outlet door of the oven outside it, where they are unloaded in appropriate containers for further processing.

To remove the humidified air from the chambers and the dryer, a contaminated air extraction system is provided, including suitable fans for recirculating the air (see the moisture extraction openings indicated in heading 8). In addition, the temperature inside the oven can be controlled by suitably positioned sources to heat the circulating air so that the desired temperature is maintained at a constant temperature, such as 160 ° F, during transport of the leaves on the conveyor inside the oven outside the microwave chambers. -180 ° F (71 ° C - 82 ° C). In a mobile system such as the one shown in Figure 3, which is intended for use in the field, the electric power is supplied by two ordinary diesel generators 9 and 10. Of course, the microwave oven can also operate stationary, powered by a traditional source of electricity.

Each of the four chambers of the dryer 3 receives microwave energy from a corresponding Microdry Model IV - 75 source, which enters the respective chamber through a divider and through two inputs located above each chamber. Below the entrances is a mode mixer that helps to distribute microwave energy. Each microwave power supply unit is a separate cabinet that houses the necessary components for the operation of a 75 kW microwave generator. The controls for the microwave generator are located on the cabinet. The units are designed to function continuously in industrial conditions without supervision. Each microwave generator can be located in or at any distance from the camera. At a distance of 50 '(127 cm), transmission losses are about 2%. In addition, each microwave generator allows industrial energy to be adjusted. The output energy can be from 0 to 75 kW at 915 MHz and can be manually adjusted via a button on the control panel or remotely from a controller by a control signal from 4 mA to 20 mA. When controlling output power from zero, the frequency spectrum becomes wide at levels below about 5 kW. Typically, the power generator for each camera is a DC source that feeds an industrial magnetron whose operation and protection are performed by circuits designed for automatic and manual mode. The electrical functions of the generator are monitored by measuring instruments located on the control panel on the cabinet door. Anode current, anode voltage, output power, heating current, electromagnetic current and reflected power are measured. The operation of electromechanical interlocks is monitored by pointing lamps located on the control panel. Each microwave cabinet has a door with a maximum width for maximum accessibility to the components. The magnetron and the respective microwave components are housed in a built-in protective housing to protect against electromagnetic interference. Installation of magnetron and electromagnet can be done through the door. The system incorporates a circulating water source installed in the cabinet that acts as an insulator in the event of high reflected power. Compressed air and water are used to cool the heat-generating components. Water cooling of the magnetron and the electromagnet is carried out with demineralized water circulating in a closed circuit, the cooling of which is carried out by a separate water source and a heat exchanger. This separate water source passes through a water and air heat exchanger into the air cooler cabinet. A high-pressure centrifugal fan is used to cool the output of the magnetron and the cathode part. Water temperature and cabinet temperature are included in the control circuit. Typical data for a microwave generator in a system of the type described are as follows:

95 KVA Input Power, 440 480 VAC, 3 Phases, 60 Hz;

75 kW output power at 915 +/- 10 MHz;

CTL magnetron tube, CWM 751;

Typical magnetron gain data are:

AC 11.4 V;

Heating current 85 A;

DC current anode voltage of 17 KV;

Anode current 5.0 A;

4.3 A direct current electromagnet;

80% efficiency;

In addition, a conventional microwave generator can use a carbon steel sheath and have a waveguide output (for example, WR 975 type) conveniently located on the top of the cabinet.

In a precision test, a microwave tobacco drying system, designed as described above, eliminates over 80% of the moisture in the leaves. In particular, a single measured sample of a 15-pound (about 6.8 kg) sheet with an approximate initial moisture content of 85% and a solids content of about 15% is carried by the thickness of a single sheet on a conveyor through a microwave chamber at a speed of about 180 pounds per hour (0.023 kg / s). The ultimate leaf weight after leaving the camera is 4.6 pounds (about 2.09 kg) or 31% of the original weight. Thus, with an estimated initial water content of leaves and a final content of 2.35 pounds (1,066 kg), a reduction of up to 18.5% is obtained.

As illustrated in Figure 2, microwave treatment of yellow tobacco in accordance with the present invention produces a dried tobacco product of golden color. According to the data cited herein, the content of carcinogenic nitrosamines, in particular NNN and NNK, in the tobacco thus dried is substantially reduced in comparison with that in conventional dried tobacco.

It has also been found that concentrated forms of electromagnetic radiation (i.e., concentrated, as opposed to simple sun exposure, can also be used to achieve the main objectives and effects of the present invention - the reduction or substantially elimination of TSNA in tobacco products). light or electric light in the visible spectrum) at higher frequencies and shorter wavelengths than the microwave regions discussed above to treat persistent collected tobacco for almost the same time with the same microwave volume. equipment. In other words, the same general and preferred methods as those discussed with respect to microwave processing when using such alternative energy sources may be applied; for example, such radiation treats tobacco at the same time after harvesting, and the leaf handles can then be removed and pressed between squeeze rolls or moistened.

To the extent that such alternative energy sources have been found to significantly reduce or substantially eliminate or prevent the formation of TSNA, none of the other embodiments tested so far is as effective in drying the leaves as the microwave irradiation described in detail herein. When using such alternative energy sources to complete the drying cycle, the irradiated tobacco leaves are preferably subjected to further treatment, for example, combining the irradiation step with a subsequent drying in a conventional oven or in an oven dryer.

In particular, it is considered that any source of electromagnetic radiation or accelerated particle beams, such as electron beams with a frequency higher than the microwave region in the standard electromagnetic spectrum, can substantially reduce or substantially eliminate or prevent the formation of TSNA when the tobacco is in a condition suitable for reducing or stopping the formation of TSNA. On the scale of the electromagnetic spectrum, where microwaves are generally defined as containing those forms of electromagnetic radiation having a frequency of 10 ¹¹ Hz and a wavelength of 3 x 10 ' ³ w, such a source of electromagnetic radiation includes, without limitation, long-range radiation infrared and infrared bands with frequencies from about 10 ¹² Hz to 10 ¹⁴ Hz and wavelengths from about 3 x 10 ³ to 3 x 10 ' ⁶ meters; UV radiation with frequencies from about 10 ¹⁶ Hz to 10 ' ⁸ Hz and wavelengths from 3 x 10' ⁸ m to 3 x 10 t; soft X-rays or lasers; cathode rays (flux of negatively charged electrons emitted by a cathode of a vacuum tube perpendicular to the surface); X-rays and gamma rays, which typically have frequencies of 10 ²¹ Hz and higher, and the corresponding wavelengths.

It will be apparent to one of ordinary skill in the art that the higher the radiation dose is supplied by the energy source, the less time the leaves are irradiated to achieve the desired results. Typically, when using such a source at a higher frequency, the irradiation time is less than 1 min, preferably less than 30 s, and in another preferred embodiment, less than 10 s. In other words, irradiation times of at least 1 s are preferred. As shown in the examples below, the radiation rate can be adjusted so that the radiation dose can be transmitted over a longer period if desired. For example, 1 megarad radiation can be delivered instantly (with an electron beam accelerator, as explained later in Example 17) or for a predetermined degree of irradiation (as in Example 19 for gamma irradiation testing in a closed chamber, where 1 megarad (10 kGrey) is transmitted at an exposure rate of about 0.8 megarad / h). In the case of high-frequency radiation sources, it is preferable to use an amount of radiation that achieves at least a 50% reduction in TSNA content compared to untreated samples. Since the specific doses of radiation and the degree of irradiation depend on the equipment in question and the type of radiation source used, it is clear to one of ordinary skill in the art that tobacco samples are preferably irradiated at doses of about 0.1 megarad up to about 10 megarads; according to another preferred embodiment, from 0.5 megarad to 5 megarad, more preferably from 0.75 megarad to about 1.5 megarad.

As shown in the following examples were made tests of various tobacco samples exposed to different sources - a beam of accelerated electrons, CO ₂ laser and gamma radiation. For each of the exemplary samples of non-dried irradiated tobacco, it is shown that it contains a substantially reduced amount of TSNA and / or substantially their content is eliminated.

In another embodiment of the invention, tobacco treatment, while still suitable for such treatment, is shown in a conventional recirculating air dryer, thereby reducing the TSNA content, albeit with poor leaf quality. Unlike a conventional baking oven, which is not as effective at reducing TSNA content and which degrades the quality of tobacco, it is heated in a conventional recirculating air dryer at about 100 ° F to about 500 ° F. (about 37.8 ° C to about 260 ° C) for 1 hour to about 5 minutes at the highest temperature can significantly reduce the content of TSNA or retain their formation in tobacco when it is in a sensitive state. treatment. According to an even more preferred embodiment, using a dryer that combines convective heating with recirculating air and microwave irradiation, the heating time can be reduced while improving the quality of the leaves. For example, when using only a convection dryer, the veins and handles are not as well dried as the rest of the leaf, resulting in dried and brittle patches. Combining microwave treatment and heating in a convection oven with recirculating air can improve the quality of the leaves as a more uniformly dried product is obtained.

Another aspect of the present invention relates to a method of reducing or substantially eliminating the content of tobacco-specific nitrosamines in tobacco for smoking, chewing or otherwise consumed, to yield a product with a substantially reduced or substantially eliminated TSNA content .

This illustrates the exposure of microwave or other irradiated tobacco to tobacco with a surprisingly low nitrosamines content. These methods are facilitated by peeling and separating the handle from the tobacco leaf from one-third to one-half its length, in particular where the steps of removing the handle and the moisture or treating the handle are not applied. When the handles are removed in this way, the microwave-treated tobacco leaves obtained do not require the use of a threshing machine, since the unwanted part of the handle is already removed. As a result, typical tobacco product losses inherent in this type of treatment are eliminated, reducing tobacco waste by approximately 10% to 30%.

The improved tobacco according to the present invention may replace wholly or partially normally dried tobacco used in any tobacco product, including cigarettes, cigars, chewing tobacco, snuff, tobacco chewing gum or sweets, pipe tobacco, or bags. a tobacco flavor additive or in foods. When used for smoking, the product of the present invention provides a less unpleasant odor while maintaining good smoking characteristics and an intact aroma with a normal nicotine content. When used for chewing, sniffing, shrinking, or as a nutritional supplement, the tobacco of our invention has a rich and pleasant aroma.

The present invention is further illustrated by the following examples which do not limit its scope.

Example 1.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F 110 ° F (38 ° C - 43.3 ° C). Samples 1 to 3 were taken from the dryer after yellowing the leaves after about 24-36 hours. Sample 1 is a leaf-free sheet and dried in a convection oven with air at about 400 ° F - 500 ° F (152 ° C - 190 ° C) for about 1 hour, at which point the leaf turns brown. Sample 2 was a yellow sheet placed in a Goldstar microwave oven, model MA-1572M (2450 MHz), heated to a maximum power of 1000 W at a simultaneous rotation of about 2.5 minutes. Sample 3 is an untreated yellow leaf used as a checklist. Samples 4 and 5 remain in a conventional oven at an increasing temperature of about 1800 ° F (82 ° C), with tobacco from sample 4 being dried outside the rack and sample 5 in the rack. Sample 6 is a dried brown sheet that has been subjected to ordinary tube drying.

Each sample was analyzed to determine the content of NNN, NAT, NAB and NNK. In this and the following examples, "TSNA" will refer to the sum of these four nitrosamines. Following a typical procedure for TSNA analysis, laboratory tests and extraction are applied - see, for example, Burton et al., “Distribution of Tobacco Constituents in Tobacco Leaf Tissue. 1. Tobacco-specific Nitrosamines, Nitrates, Nitrite and Alkaloids ”, J.Agric. Food Chem., Volume 40, No. 6, 1992, determining the amount of individual nitrosamines in a TEA analyzer, model 543 of Thermedics Inc., coupled to a Helwett-Packard model 5890A gas chromatograph. The results obtained are shown in Table 1. All data in the following tables are in micrograms of nitrosamines in one gram of the sample, i. microg / g.

Table 1

Sample # NNN NAT + NAB NNK TSNA 1 - yellow dried leaf part 0.0310 0.843 <0.0004 0.1157 2 - yellow subjected to microwave irradiation <0.0004 <0.0006 <0.0005 <0.0014 3 - yellow control 0.0451 0.1253 0.0356 0.2061 4 - quickly dried outside the rack 0.6241 1.4862 1.2248 3.3351 5 - quickly dried in the rack 0.7465 1.5993 1.3568 3.7044 6 -normal tube-dried 1.0263 1.7107 2.2534 4.9904

Example 2.

Virginia varietal tobacco was harvested. Sample 7 is a freshly sliced green leaf used as a control, and Sample 8 is a freshly sliced green leaf subjected to microwave irradiation for about 20 s in a multiple-mode microwave device manufactured by MicroDiy of Louisville, Kentucky, 2.5 kW. and frequency 2450 MHz. Samples 9 to 12 are made from normal tube-dried brown tobacco. Sample 9 is tobacco-shaped tobacco; sample 10 - free-cut tobacco for the manufacture of cigarettes; samples 11 and 12 are the same as samples 9 (cigarette) and sample 10 (free tobacco) except that they have been subjected to microwave irradiation under the same conditions as sample 8. TSNA content was analyzed in the same way , as in Example 1, with the results shown in Table 2.

Table 2

Sample # NNN NAT + NAB NNK TSNA 7 - freshly cut checklist <0.0104 0.126 0.0005 0.126 8 - freshly sliced microwave irradiated 0.029 0.135 0.0004 0.164 9 - cigarette control 1,997 3,495 2.735 8.226 10 - control free 2.067 3.742 2,982 8.791 11 - from a cigarette microwave irradiated 2,056 3.499 2,804 8.359 12 - free microwave irradiation 2.139 3.612 2,957 8,707

Example 3.

The tobacco cigarette blends shown in Table 3 were purchased arbitrarily from various retailers in Lexington, Kentucky, and their TSNA content was analyzed according to the procedure described in Example 1.

Table 3

Sample # Code # NNN NAT + NAB NNK TSNA 13 - Marlboro king - pc 288292 3.565 4.538 1.099 9.202 14 - Marlboro king - pc 288292 4.146 4,992 1.142 10.27 9 15 - Marlboro -king pc 288292 3.580 4.290 1.106 8.977 16 - Marlboro-king pc 288292 3.849 4,748 th most common 1.130 9.728 17 - Marlboro - lights 100's-bx 288192 4,604 5,662 1.223 11.48 9 18 - Marlboro - lights - 100's - pc 288182 3,471 3.859 1.211 8.541 19 - Marlboro - lights - 100's - pc 288182 3,488 4.136 I 1,074 8.698 20 - Marlboro - lights 100's-pc 288182 3.566 4.240 1.164 8.970 21-Winston 100's pc 123143 2.311 2,968 th most common 1,329 6,608 22 - Winston - king 123103 2.241 2.850 1.256 6.348 23 - Winston - king - bx 125123 2.162 2.831 1,326 6.319 24 - Winston - king - bx 123123 2.577 3.130 1.207 6.914 25 - Winston - king - pc 123103 1,988 2.563 1.234 5,786 26 - Winston - lights - 100's - pc 123133 2.161 2.706 1.258 6.124 27 - Winston lights - 100's - pc 123133 2.189 2.699 1.262 6.150 28 - Winston lights - 100's pc 123133 2,394 3,385 2.330 8.109

Example 4.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F -110 ° F 40 (38 ° C - 43.3 ° C). After yellowing the leaves for about 24 to 36 hours of drying, they are removed and microwave irradiated for about 2.5 minutes in a Goldstar type MA1572M (2450 MHz) dryer at a maximum power of 1000 45 W and simultaneously rotated. In this procedure, the leaves are effectively dried, although they do not turn brown but retain their golden yellow color. Then they are cut and cigarettes are made. Samples 29 to 33 were taken from the “Red Full Flavor” batch, and samples from 34 to 38 were taken from the “Blue Light” batch. Samples 39 to 42 are cigarettes purchased from a specialty store for health-friendly products under the Natural American Spirit brand. The content of TSNA in samples 29 to 42 was analyzed in the same manner as in example 1, with the results shown in Table 4.

Table 4

Sample # NNN NAT + NAB NNK TSNA 29 - RED FULL FLAVOR REP 1 0.138 0.393 <0.0005 0.532 30 - RED FULL FLAVOR REP 2 0.192 0.231 <0.0005 0.423 31 - RED FULL FLAVOR REP 3 0.129 0.220 <0.0007 0.349 32- RED FULL FLAVOR REP 4 0.145 0.260 <0.0007 0.406 33 - RED FULL FLAVORREP 5 0.140 0.239 <0.0006 0.434 AVG 0.149 0.279 <0.0006 0.429 STD 0.022 0.062 0.0001 0.059 34-BLUE LIGHT REP 1 0.173 0.162 <0.0005 0.335 35-BLUE LIGHT REP 2 0.046 0.229 <0.0005 0.275 36-BLUE LIGHT REP 3 0.096 0.188 <0.0005 0.285 37 - BLUE LIGHT REP 4 0.067 0.215 <0.0005 0.282 38 - BLUE LIGHT REP 5 0.122 0.218 <0.0005 0.341 AVG 0.101 0.202 <0.0005 0.304 STD 0.044 0.024 0.0000 0.028 39 - NATURAL AMERICAN SPIRIT 0.747 1.815 1,455 4,017 40 - NATURAL AMERICAN SPIRIT 0.762 1,805 1,458 4.025 41 - NATURAL AMERICAN SPIRIT 0.749 1.826 1.464 4.039 42 - NATURAL AMERICAN SPIRIT 0.749 1.760 1.462 3,971 AVG 0.752 1,802 1.460 4,013 STD 0.006 0.025 0.004 0.025

The AVG table indicates the average of the samples and the STD the standard deviation from the average.

Example 5.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F - POT (38 ° C - 43.3 ° C). Samples 43 and 44 were taken from the dryer after yellowing the leaves - about up to 36 h after drying, and were microwave irradiated for 20 and 30 s in the described device with multiple modes

MicroDry at about 6 kW. After irradiation, samples 43 and 44 are dried golden yellow leaves. Samples 45 to 51 are dried brown leaves that have been subjected to ordinary tube drying. Sample 45 was control and samples 46 and 47 5 were dried in a conventional oven heated to about 400 ° F - 500 ° F (152 ° C - 190 ° C) for 1 min and 3 min, respectively. Samples 48 and 49 were subjected to 915M Hz microwave irradiation at 50 kW for 10 and 40 s in a 10 Waveguide device, model WR-975, a large multi-mode dryer manufactured by MicroDry capable of adjusting power from 0 to 75 kW. Samples 50 and 51 are sliced (reconstituted) tobacco made from tubular dried leaves. Sample 50 was microwave irradiated in a Waveguide dryer at 50kW for approximately 1.5 min, and sample 51 was dried in a conventional oven heated to about 400 ° F 500 ° F (152 ° C - 190 ° C) for 3 min. . The content of TSNA in these samples was analyzed in the same way as in Example 1, with the results shown in Table 5.

Table 5

Sample # NNN NAT + NAB NNK TSNA 42 - 20 sec. microwave radiation <0.0106 <0.1068 <0.0007 <0.1181 44 - 30 sec. microwave radiation <0.0103 <0.1065 <0.0004 <0.1172 45 - control; without radiation 0.92 2.05 3.71 6.68 46 - conv. dryer I min. 1.14 2.41 5.10 8.66 47 conv. oven 3 min. 0.89 2.06 2.68 5.64 48 - Waveguide 10 sec. 50kW 1.00 2.31 3.29 6.59 49 - Waveguide 10 sec. 50kW 0.62 1.55 1.69 3.86 50 - Waveguide sliced tobacco, 1.5min. 50 kW 4.22 4.91 0.99 10.12 51 - cut tobacco, conv. oven 3 min. 4.76 5.60 1.08 11.44

Example 6

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F -110 ° F (38 ° C - 43.3 ° C). Samples 52 to 55 were cigarettes from 40 yellow tobacco removed from the oven after about 24-36 h and subjected to 2 minutes of irradiation in a Goldstar microwave oven model MA-1572M (2450 MHz) at a maximum power of 1000 W. by comparison, samples 61 and 62 are 45 cigarettes made from the leaves after ordinary tube drying without microwave treatment. Sample 56 is a dried leaf; sample 57 - yellow leaf after the ordinary atmospheric drying step, but not wholly dried; sample 58 is a dried sheet and samples 59 and 60 are dried veins. The content of TSNA in these samples was analyzed in the same way as in Example 1, with the results shown in Table 6.

Table 6

Sample # NNN NAT + NAB NNK TSNA 52 - Goldsmoke cigarettes 0.12 0.23 0.03 0.38 53 - Goldsmoke II, 85 mm 0.062 0.326 0.016 0.404 54 - Goldsmoke 85 mm 0.128 0.348 0.029 0.504 55 - Goldsmoke 100's Type B 0.166 0.317 0.047 0.531 56 - Type M-M 3.269 4,751 0.833 8.853 57-type B-C 0.267 0.720 th most common 0.954 1.941 58 - sheet M-C 0.933 1,456 1.968 4,356 59-WM 0.996 1.028 0.408 2.432 60-SM 1.745 1,753 0.306 3,804 61 - Goldsmoke control 1,954 1.544 0.492 3.990 62 - Goldsmoke control 1,952 1,889 0.424 4.265

Example 7.

Virginia tobacco is harvested. Samples 63 and 64 are dried fresh sliced green tobacco, although more than one week elapsed before TSNA measurement, so some atmospheric drying has taken place. The other sample leaves were placed in a conventional tube-dryer at about 100 ° F -110 ° F (38 ° C - 43.3 ° C). Sample 68 is a sheet removed from the dryer after yellowing for about 24 to 36 hours and then subjected to microwave irradiation for 40 s in the previously described 25 kW kW-type Waveguide.

Samples 64 and 65 (leaves) and 67 and 70 (reconstituted tobacco leaf or "sliced" tobacco) show the effects of the invention when the dried tobacco is rehydrated and subjected to microwave irradiation. Samples 64 and 65 are leaves that have undergone ordinary tube drying. Sample 64 is a 20 15 sheet, rehydrated by passing through a water jet for about 5-10 s, during which time a considerable amount of moisture is absorbed. Each of the samples 64 and 65 is then microwave irradiated for 40 s in a 25 kW multiple waveguide mode device. Samples 67 and 70 are a recovered tobacco leaf made from dried leaves. Sample 67 was re-hydrated by adding water to absorb a significant amount after being subjected to microwave irradiation under the same conditions as sample 64. Sample 70 was not irradiated. Samples 69, 71 and 72 are further dried leaves serving as control samples. The content of TSNA in these samples was analyzed35 in the same manner as in Example 1, with the results shown in Table 7.

> persons 7

Sample # NNN NAT + NAB NNK TSNA 63 - control, not dried 0.010 0.263 0.000 0.274 64 - dried 40 sec., Moistened 0.737 1.252 1.893 3,882 65 - dried 40 sec. 0.767 1.520 2.229 4.516 66 - not dried 40 sec. 0.010 0.261 0.000 0.272 67 - cut tobacco, dried, 40 sec., Moistened 0.769 1,328 0.308 2,405 68 - not dry for 40 seconds, 25kW WAVEGUIDE 0.051 0.244 0.014 0.308 69 - dried, control 0.866 1.548 2.545 4,960 70 - Control, sliced tobacco 1.872 2.536 0.789 5.197 71 - control, "AL" whole sheet 0.230 0.606 0.746 1,582 72 - SML full sheet 0.413 0.884 1.514 2.810

Example 8.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F -110 ° F (38 ° C - 43.3 ° C). Sample 73 is a leaf taken from the dryer after standing for about 24-36 hours and turning yellow. It is microwaved for about 2 minutes in a Goldstar type MA-1572M dryer at its highest setting. Samples 74 to 76 are normally tube-dried tobacco, 1C as sample 74 is a control. Samples 75 and 76 were re-hydrated as described in Example 7 (sample 64), then microwave irradiated in a MicroDry (2450 MHz) device for 20 s and 40 s, respectively, at a power of about 6 kW. Samples 77 to 79 were reconstituted tobacco leaf obtained from tubular dried leaves. Sample 77 was control and samples 78 and 79 were re-hydrated as described in Example 7 (sample 67). Each of the samples 78 and 79 was microwave irradiated for about 30 s in a MicroDry device. Sample 78 was placed at the bottom of the oven and sample 79 several inches higher, with the sheet placed on a styrofoam cup to achieve more uniform heating. The content of TSNA was analyzed in the same way as in Example 1, with the results shown in Table 8.

Table 8

Sample # NNN NAT + NAB NNK TSNA 73 - yellow, irradiated 0.052 0.260 <0.0004 0.313 74 - A - checklist, dried 1.168 1,904 1.662 4,734 th most common 75 - B - irradiated 20 sec. 0.791 1,705 1.115 3.611 76 - With an irradiated 40 sec. 0.808 1.624 1.160 3,592 77 - checklist, sheet 4.417 3.697 0.960 9.073 78 - 30 sec. 2,755 2,553 0.644 5,952 79 - 30 sec., Higher 1,606 1.732 0.350 3.687

Example 9.

Samples 80 and 81 are chewing tobacco brand Redman purchased at retail. Sample 80 is a control and Sample 81 is microwave irradiated for about 1 - 2 min in a Goldstar type MA-1572M dryer at the highest power. Samples 82 and 83 are Skoal sniffing tobacco purchased at retail. Sample 82 is control and sample 83 is irradiated in the same manner as sample 81. The measured content of TSNA is shown in Table 9 below.

Table 9

Sample # NNN NAT + NAB NNK TSNA 80 - chewing tobacco before irradiation 0.712 0.927 0.975 1.713 81 - chewing tobacco after irradiation 0.856 0.906 0.122 1,884 82 - Smoking tobacco before irradiation 4,896 10.545 1,973 17.414 83 - post-irradiation snuff tobacco 6.860 th most common 14.610 1.901 23.370

Example 10.

In order to check that more TSNAs accumulate over time even after the yellow tobacco was subjected to microwave irradiation according to the invention, additional samples (indicated by - A) of the cigarettes tested in Example 4, samples 29, 35 and 39 were tested control. Re-testing for TSNA content was performed more than seven months after the first measurement as indicated in 5 Example 4. The results obtained are shown in

Table 10.

Table 10

Sample # NNN NAT NAB NNK TSNA 29A-RED FF REP # 1 0.1109 0.1877 0.1078 0.0015 0.4079 35 A - BLUE LIGHT REP # 2 0.0508 0.1930 0.1075 0.0012 0.3525 39A - NATURAL AMERICAN SPIRIT REP # 1 0.6151 1.2357 0.1072 0.9302 2.8882

An example. 11.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F -110 ° F (38 ° C - 43.3 ° C). After a stay of about 24 - 36 hours and yellowing, they are removed and subjected to microwave irradiation for about 2 to 2.5 minutes in a Goldstar type dryer, MA-1572M model set to its highest power. Each leaf is effectively dried to a golden yellow color. Some of the samples referred to as "basic" are then processed as finely ground substances, which are used, for example, as chewing gum supplements, suction candy and nutritional supplements. The TSNA content of the samples shown below was measured more than six months after microwave irradiation of the leaves using the procedure described in Example 1. The results are shown in Table 11.

Table 11

Sample # NNN NAT NAB NNK TSNA 84 - basic 0.0013 0.0018 0.0018 0.0015 0.0064 85 - basic 0.0469 0.0011 0.0011 0.0009 0.0831 86 - basic 0.0009 0.0013 0.0013 0.0011 0.0615 87 - basic 0.0113 0.1078 0.1078 0.0015 0.2284 88 - basic 0.0569 0.1071 0.1071 * 0.0009 0.3051 89 - basic 0.0109 0.1073 0.1073 0.0011 0.2835 90 - basic 0.0008 0.0011 0.0011 0.0009 0.0038 91 - basic 0.0009 0.0012 0.0012 0.0010 0.0044 92 - basic 0.0012 0.0017 0.0017 0.0014 0.1101 93 - basic 0.0013 0.0019 0.0019 0.0015 0.0576 94 - basic 0.0012 0.0017 0.0017 0.0014 0.0657 95 - basic 0.0506 0.0013 0.0013 0.0010 0.1518 96 - basic 0.0017 0.0024 0.0024 0.0019 0.0954 97 - basic 0.0012 0.0017 0.0017 0.0014 0.0061 98 - basic 0.0016 0.0023 0.0023 0.0019 0.0082 99 - basic 0.0342 0.0016 0.0016 0.0013 0.0386 100 - basic 0.0014 0.0020 0.0020 0.0016 0.0070 101 - sheet 0.0013 0.0539 <0.0019 <0.0016 0.0587 102 - sheet 0.0009 0.0012 <0.0012 <0.0010 0.0043 103 - cut leaves 0.0202 0.0327 <0.0007 <0.0006 0.0542

Example 12.

Virginia varieties were harvested and the leaves were placed in a regular tube oven at about 100 ° F -110 ° F (38 ° C - 43.3 ° C). Samples 104 and 105 are normally 5 tube-dried sheets without microwave irradiation. Sample 104 is dried veins and example 105 is a dried leaf portion. Sample 106 is yellow tobacco removed from the dryer after yellowing the leaves after about 24-36 hours of drying. 10

The leaves were then microwaved for 2 to 2.5 minutes in a Goldstar type MA-1572M type oven at highest power. All leaves are effectively dried and have a golden yellow color. Some of them were further processed in the traditional way to obtain a tobacco extract, which in the analyzes was designated sample 107. The content of TSNA in samples 104 to 107 was measured according to the procedure described in Example 1, and the results are shown in Table 12.

Table 12

Sample # NNN NAT & NAB NNK TSNA 104 - control veins 0.083 0.180 <0.003 0.266 105 - control leaf part 0.928 1.367 2,613 4,908 106 - irradiated leaves <0.004 <0.006 <0.005 <0.015 107 - irradiated extract <0.004 <0.005 <0.004 <0.013

Example 13.

Virginia varieties were harvested and the leaves were placed in a conventional tube oven at about 100 ° F -110 ° F 25 (38 ° C - 43.3 ° C). Samples 108 and 109 are normally tube-dried sheets without microwave irradiation. Sample 108 represents the dried leaf portion and sample 109 the dried veins. Samples 110 and 111 are yellow tobacco extracted from the dried 30 shoots after yellowing of the leaves after about 24-36 hours of drying. They are then heated in an air-circulation convection oven, type Sharp Carousel Convection / Microwave, model No. R-9H84B. The tobacco from sample 110 is heated rapidly to about 300 ° F (149 ° C) for 5 - 10 minutes. Sample 111 tobacco is heated much slower at lower temperatures, starting from 100 ° F (38 ° C) in steps to about 150 ° F (66 ° C) for more than 10 minutes, with a total heating time of over 20 min. The content of TSNA in samples 108 to 111 was measured according to the procedure described in Example 1, the results being shown in Table 13.

Table 13

Sample # NNN NAT & NAB NNK TSNA 108 - control sheet 1.267 2,509 1,377 5.153 109 - control veins <0.004 0.464 <0.004 0.472 110 - convection; quickly <0.004 <0.005 <0.004 <0.013 111 - convection; slow <0.003 <0.004 <0.003 <0.010

Although the content of TSNA when heated in a convection oven is reduced, the quality of tobacco is worse than that under microwave irradiation according to preferred embodiments of the invention. In addition, the heating time should be longer than that of microwave treatment or other forms of high-frequency 50 radiation. In particular, convection heating cannot leave the desired golden yellow color, with a tendency to dry and break the leaves, and the veins are not well dried. In contrast to the most preferred embodiments of the present invention, microwave irradiated leaves are effectively dried and retain their golden yellow color after treatment, remaining flexible and elastic for further treatment, in particular for cigarettes. The tobacco leaf portion in the sample, dried in a convection oven, tends to break into small powder particles.

Example 14.

After collecting Kentucky Burley tobacco at the beginning of the yellowing of the leaves about 24 to 48 hours after traditional drying, they were treated as follows: Samples 112 to 117 were leaves of the same batch, leaves of sample 112 being irradiated at approximately the same time. conditions as sample 106 in Example 12. The leaves are effectively dried and have a golden yellow color. The leaves of samples 113, 114 and 117 were heated in the same convection oven with air circulation as described in Example 13, with sample 113 being heated under approximately the same conditions as sample 110; sample 114 as sample 111, and sample 117 was heated at about 5 350 ° F (177 ° C) for about 20 minutes. Samples quality 113,114 and 117 is similar to samples 110 and 111 of Example 13. Samples 115 and 116 were heated in a Sharp Carousel Convection / Micro wave dryer described in Example 13, using a 10 microwave combined (3 0%) / convection 300 ° F (149 ° C) heating to a golden yellow color and effectively drying the leaves. The content of TSNA in samples 112 to 117 was measured according to the procedure described in Example 1 15, the results being shown in Table 14.

Table 14

Sample # NNN NAT & NAB NNK TSNA 112 microwave <0.007 <0.010 <0.008 <0.025 113 - convection heating <0.003 <0.004 <0.003 <0.010 114 - convection heating <0.012 <0.017 <0.014 <0.043 115 - microwave (30%) / convection heating. <0.002 <0.003 <0.003 <0.008 116 - microwave (30%) / convection heating. <0.002 <0.003 <0.002 <0.007 117 - convection heating 0.131 0.156 <0.003 0.290

Example 15.

A Virginia crop was harvested and the leaves were placed in a regular tube oven at about 100 ° F-110 ° F (38 ° C-43,3 ° C). Samples 118 to 120 are leaves taken from the dryer after the onset of yellowing, and shortly thereafter subjected to microwave irradiation in a conventional kitchen type microwave for about 2 to 2.5 min until effective drying and a golden yellow color without burning. . Samples 121 to 123 were of Kentucky Burley tobacco, treated after the onset of yellowing as follows: the leaves of sample 121 were placed in a traditionally used tobacco oven with an eccentric axis of rotation at about 200 ° F (93 ° C). until they start to turn brown and somewhat dry. The leaves of sample 122 were microwave irradiated in the high-power Goldstar dryer described above for about 2 min, re-hydrated, and placed in the dryer with an eccentric axis of rotation until they became a little brown when considered brown. the aroma increases. Sample 123 was treated in the same way as sample 122 except that the irradiation was for about 1 min and was not re-hydrated before being placed in the dryer with an eccentric axis of rotation. The content of TSNA was measured in the same way as in Example 1, with the results shown in Table 15.

Table 15

Sample # NNN NAT & NAB NNK TSNA 118 <0.003 0.150 <0.003 0.156 119 <0.003 <0.004 <0.003 <0.010 120 <0.002 <0.003 <0.003 <0.008 121 0.486 1,059 <0.003 1.548 122 <0.004 <0.005 <0.004 <0.013 123 <0.003 <0.004 <0.004 <0.011

Example 16.

After standing for about 2-3 days on the North Carolina Burley tobacco, when the leaves begin to turn yellow, they are treated as follows. The leaves of sample 118 were microwave irradiated in the Goldstar type dryer described above with high power for about 2 min, after which they were effectively dried and turned a golden yellow color. The content of TSNA was measured in the same way as in Example 1, with the results shown in Table 16.

Table 16

Sample # NNN NAT & NAB NNK TSNA 118 0.024 0.048 <0.001 0.073

Example 17.

This example demonstrates the effectiveness of using an electron beam to reduce the content of TSNAs or substantially prevent their formation in yellow tobacco leaves. The North Carolina Burley tobacco was harvested. Samples 119 to 122 are leaves normally dried under atmospheric conditions until effectively dried when they turn brown. Sample 119 was untreated and control. Samples 120 and 121 were pipelined and electron beam irradiated using a Dynamitron-type electron accelerator manufactured by Radiation Dynamics, Inc., Edgewood, N. Y. at a radiation level of 1 megarad. The leaves of sample 122 were microwave irradiated in the Goldstar type dryer described above at high power for about 2 minutes. Sample 123 is tobacco taken from the top of a Burley leaf after it has started to turn yellow. Sample 124 is part of veins taken from the same plant as sample 123, which are still somewhat green. Samples 125 and 126 are whole Burley leaves in yellow. Each of the samples 123 to 126 was irradiated with an electron beam in the Dynamitron accelerator cited above under the same conditions as samples 120 and 121. The TSNA content of all samples was then measured by the procedure described in Example 1, the results being shown in Table 17.

Table 17

Sample # NNN NAT & NAB NNK TSNA 119 - control, dried 3.6351 1.0847 0.0470 4.7668 120 - high power; dried 6.5718 3.7037 0.4368 10.7123 121 - low power, dried 4.4771 1.6112 0.7468 6.8369 122 - irradiated, dried 4.8974 1.6393 1.1200 7.6567 123 - yellow, leaf tip 0.1812 0.3667 0.0013 0.5492 124 - green, veins 0.1918 0.8310 0.0016 1.0243 125 - whole sheet 0.0014 0.1019 0.0016 0.1048 126 - whole sheet 0.0646 0.2465 0.0019 0.3130

The above data indicate that electron beam irradiation proves effective in preventing the formation of significant amounts of tobacco-specific nitrosamines in yellow leaf samples, but they are not sufficiently dried as when microwave leaves are in the same state. the radiation described in the other examples of the application. Therefore, in the industrial application of electron beam irradiation, an additional drying step may be required, such as passing the irradiated leaves through a conventional dryer.

Example 18

Through this example, it is shown that the objectives of the present invention for low TSNA content are also achieved by laser beam irradiation with high energy beams. A CO ₂ laser model LX-20SP, manufactured by Luxar Corporation, was used to irradiate yellow tube-dried tobacco leaves of Virginia variety when about 2-3 days after harvesting. A NovaScan device is used that works with the Superpulse E program, which10 determines the degree of irradiation by the number of crawls per second. Option E10 is used which provides 10 bypass per second. Eight sub-samples from sheets T-1 to T-8 were irradiated according to the following protocol:

E10-2W T-1 - 1 detour on each side T-2 - 2 rounds on each side T-3 - 3 rounds on each side T-4 - 4 rounds on each side E10-4W T-5 - 1 detour on each side T-6 - 2 rounds per side T-7 - 3 rounds on each side T-8 - 4 rounds on each side

At 2W, approximately 120 mJ of energy is supplied at each scan or crawl, while at approximately 4 W, approximately 240 mJ of energy is supplied.

Sub-samples T-1 to T-4 were combined and mixed, and a sheet 127 was obtained, which was tested for TSNA content by the method described in Example 1. Sub-samples T-5 to T8 were also combined and mixed and a sample sheet 128 was obtained from them. The content of TSNA in the two samples was similarly studied and the results are shown in Table 18.

Table 18

Sample # NNN NAT & NAB NNK TSNA 127 0.1031 0.2025 0.0006 0.3061 128 0.1019 0.1287 0.0010 0.2315

As the samples of Example 17, and the samples irradiated with CO ₂ laser, are not dried as effectively as those subjected to microwave irradiation, although the content of TSNA is low. It is therefore necessary to include an additional drying step in order to accelerate the drying process. After irradiation with a laser beam from the _CO2 laser, but prior to testing for content of TSNA six of the eight samples were somewhat brown, without affecting the content of TSNA.

Example 19.

This example shows that gamma radiation is also effective in preventing the production of significant amounts of TSNA in yellow tobacco. The Virginia tobacco tuber was sampled for study about 2–3 days after normal atmospheric drying just after yellowing the leaves. Each of the samples 129-132 represents the leaf portion of the yellow tobacco leaves and is subjected to a gamma radiation of 10 kGrey (1 megarad) in a closed chamber 50 ra at an intensity of 8kGrey (0.8 megarad) per hour, samples were examined in the same manner as reco total irradiation time is about 75 min. the results are given in Table 19.

The TSNA content is then irradiated

Table 19

Sample # ΝΝΝ ΝΛΤ & ΝΛΒ ΝΝΚ TSNA 129 0.098 0.225 0.057 0.380 130 <0.001 <0.001 <0.001 <0.003 131 <0.001 <0.001 <0.001 <0.003 132 0.033 0.079 <0.001 0.113

It will be apparent to those skilled in the art that various changes and modifications may be made to preferred embodiments without departing from the scope and spirit of the invention. Therefore, the above description is given by way of illustration only and does not limit the invention.

Claims

Claims (28)

1. A method of treating tobacco to reduce the content of nitrosamines or substantially prevent their formation in a harvested tobacco plant, the method 25 comprising subjecting at least a portion of the tobacco plant to high frequency irradiation for a certain period of time, characterized in that the radiation is applied until the portion is dry, the yellow and tobacco leaves of the plant are in yellowing stage 3 0 before it turns brown and before there is a significant destruction of cellular integrity, allowing the condition to block and the formation of the same nitrosamines, the irradiation administration time being sufficiently precise to prevent substantially the formation of at least one nitrosamine. Method according to claim 1, characterized in that the high frequency irradiation is microwave and is applied to the tobacco leaf or part thereof after the leaf yellowing begins and before the tobacco specific nitrosamines in the leaves, such as tobacco, have accumulated the leaves or parts thereof are arranged in a layer with a thickness of one leaf. 45 A method according to claim 2, characterized in that, prior to irradiation, the tobacco plants have pre-removed leaf handles and are pressed to remove excess moisture or treated with steam. 50 Method according to claim 2, characterized in that the tobacco plants with handles are pre-pressed to remove excess moisture or treated with steam prior to irradiation. A method according to claim 2, characterized in that the high frequency radiation is at a frequency higher than the microwave regions of the electromagnetic spectrum. 6. A method according to claim 5, wherein the tobacco plants are tubular dried and irradiation is carried out over a period of 24 hours to about 72 hours after picking. Method according to claim 5, characterized in that the irradiation is carried out for at least 1 s at a predetermined power. A method according to claim 1, characterized in that at least one tobacco-specific nitrosamine is selected from the group consisting of N'-nitrosonornicotine, 4- (Ν-ΗΗτροzomethylamino) -1- (3-pyridyl) -1-butanone, N 'nitrosoanatabine and N-nitrosoanabasin. A method according to claim 2, characterized in that drying is carried out after the irradiation step. 10. The method of claim 2, wherein the irradiation is performed by a laser beam. 11. The method of claim 2, wherein the irradiation is carried out by an electron beam generated by an electron accelerator (gamma radiation). A method of producing a tobacco product according to claim 1, characterized in that the applied radiation has a higher frequency and a shorter wavelength than the microwave region of the electromagnetic spectrum. A tobacco product obtained by the method of claim 1, comprising a dried non-green or yellow, edible Virginia tobacco tubing that is substantially free of organic liquids used to extract bulk organic materials, characterized in that has a total N'-nitrosonornicotine, 4- (T4-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N'-nitrozoanabasin content of less than 0.2 µg / g. Tobacco product according to claim 13, characterized in that it has a total content of HaN'-nitrosonornicotin, 4- (L1-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrozoanatabine and N ' -Nitrozoanabasin 0.05 µg / g or less, in which the dried non-green or yellow tobacco is selected from the group consisting of Virginia tubing and Burley varieties. A tobacco product obtained by the method of claim 1 comprising dried non-green or yellow, tobacco-grade tobacco for leaf tube drying, characterized in that it has a total content of HaN'-nitrosonornicotin, 4 (N- nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasine less than 0.2 µg / g. Tobacco product according to claim 15, characterized in that the total content of N'-nitrosonornicotine, 4- (L-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N ' -Nitrozoanabasin is 0.05 µg / g or less, the dried non-green or yellow tobacco being selected from the group consisting of Virginia tubing and Burley varieties. Tobacco product according to claim 13, characterized in that the dried non-green or yellow tobacco is selected from the group consisting of US Virginia varieties for tube drying and US Burley varieties. 18. The tobacco product of claim 15, wherein the dried non-green or yellow tobacco is selected from the group comprising U.S.A. Virginia tubing and Burley varieties. A tobacco product obtained by the method of claim 1 comprising dried Sunday or yellow edible tobacco substantially free of organic liquids used to extract magnifying organic materials, characterized in that it contains 4- ( N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone 0.002 µg / g or less. 20. A tobacco product obtained by the method of claim 1 comprising dried non-green or yellow edible tobacco in the form of a leaf, characterized in that it contains 4- (1 N-nitrosomethylamino) -1- (3pyridyl) -1-butanone 0.002 µg / g or less. The tobacco product according to claim 19 or 20, characterized in that it contains 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1 butanone 0.001 µg / g or less. 22. Tobacco product according to any one of claims 19,20 and 21, characterized in that the dried non-green or yellow tobacco is a Virginia pipe-drying variety. 23. Tobacco product according to any one of claims 19,20 and 21, characterized in that the dried non-green or yellow tobacco is a Burley variety. A tobacco product according to any one of claims 13 or 15, characterized in that the total content of HaN'-nitrosonornicotin, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrozoanabatin and N'-nitrozoanabasin is 0.15 µg / g or less. A tobacco product according to claim 24, characterized in that the total content of N'-nigrosonornicogin, 4- (N-nitrosomethylamino) -1 (3-pyridyl) -1-butanone, N'-Ngrozoanagabine and N-nitrosoanabasin is 0.1 microg / g or less. 26. A tobacco product obtained by the method of claim 1 comprising dried non-green or yellow tobacco for consumption, characterized in that it contains at least one tobacco-specific nitrosamine selected from the group consisting of N'-nitrosonornicotin, 4 ( N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasins whose content is at least about 75% lower than that of tobacco-specific nitrosamine in dried brown tobacco of the same crop that is not dried green or yellow tobacco, but which brown tobacco is traditionally cured in the absence of steps to reduce the content of said at least one tobacco-specific nitrosamine. 27. The tobacco product of claim 26, wherein said content of at least one tobacco-specific nitrosamine is at least about 90% lower than the content of the same tobacco-specific nitrosamine in the dried brown tobacco of the same crop, but which brown tobacco has traditionally been dried in the absence of the steps of reducing the content of at least one tobacco-specific nitrosamine. 10 28. The tobacco product of claim 27, wherein said content of at least one tobacco-specific nitrosamine is at least about 95% lower than the content of the same tobacco-specific nitrosamine in dried brown tobacco of the same crop but which is brown tobacco has traditionally been dried in the absence of the steps of reducing the content of at least one tobacco-specific nitrosamine given.