KR100458405B1 - Method of Treating Tobacco to Reduce Nitrosamine Content, and Products Produced Thereby - Google Patents

Abstract

The present invention relates to a method of reducing or preventing the formation of carcinogenic nitrosamines in plants having leaves harvested, such as tobacco and cannabis. The method of the present invention relates to exposing the plant to microwaves and / or high frequency radiation at a suitable time during the ripening period. Tobacco products having nitrosamines specific to tobacco similar to those of freshly harvested green tobacco have produced tobacco products, such as cigarettes, cigars, and the like, suitable for human consumption in accordance with the present invention. Tobacco products prepared in the preferred embodiment are dried golden leaves that have little known carcinogens, NNN and NNK, compared to commonly aged tobacco.

Description

Methods of treating tobacco to reduce nitrosamine content and products produced thereby {Method of Treating Tobacco to Reduce Nitrosamine Content, and Products Produced Thereby}

Other documents describe how to use microwave energy to dry a harvest. The use of microwave energy to cure tobacco is described in Hopkins US Pat. No. 4,430,806. In US Pat. No. 4,898,189, Bochnowski teaches the use of microwaves to treat green tobacco to control the wet content in manufacturing for storage or transportation. U.S. Patent No. 3,699,976 describes that microwave energy can prevent insect infection of tobacco. Also described is a technique (US Pat. No. 4,821,747) for impregnating tobacco with an inert organic liquid by a sluicing method to extract effervescent organic material, where the mixture is exposed to microwave energy. In another embodiment, microwave energy is described as the drying mechanism of the material containing extruded tobacco (US Pat. No. 4,874,000). In US Pat. No. 3,773,055, Stungis describes the use of microwaves to dry and inflate cigarettes made from wet tobacco.

Previously, attempts were first made to use filters in smoking tobacco to reduce tar and harmful carcinogenic nitrosamines. Attempts have also been made to use additives to prevent the action of harmful carcinogens in tobacco. Despite these efforts, it has failed to reduce the tumor morbidity associated with tobacco use. Freshly harvested green tobacco is known to be virtually free of nitrosamine carcinogens. See, for example, Weinik et al., "Effect of Air-Curing on the Chemical Composition of Tobacco," Recent Advances in Tobacco Science, Vol. 21, pp. See below, Symposium Proceeding 49th Meeting Tobacco Chemists' Research Conference, Sept. 24-27, 1995, Lexington, Kentucky (hereinafter referred to as "Birnik et al."). However, aged tobacco contains harmful carcinogens N'-nitrosonornicotine (NNN) and 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK) It is known to contain various nitrosamines. It is widely accepted that after harvesting, such nitrosamines are formed during the aging process detailed herein. Unfortunately, freshly harvested green tobacco is not suitable for smoking or other consumption.

In 1993 and 1994, Burton et al., University of Kentucky, described "Reduction of Nitrite-Nitrogen and Tobacco N'-Specific Nitrosamine In Air-Cured Tobacco By Elevating Drying Temperature", Agronomy & Phytopathology Joint Meeting, CORESTA, As reported in the Abstract of Oxford 1995, certain experiments were carried out on tobacco specific nitrosamines (TSNA). Burton et al., At various stages of air-curing, including late yellowing (EOY), EOY + 3, and EOY + 5, dried harvested tobacco leaves at 71 ° C. for 24 hours to determine the amount of nitrosamines. Reported some reduction. It also mentions lyophilization and microwave methods without specific details or results. The Applicant was convinced that the microwave study was considered unsuccessful in an actual study conducted by Burton et al. At the University of Kentucky. A particular aspect of the 1993-94 study of Burton et al., Under the name "Modified Air-Curing", was published by Weinik et al., Supra, pp. 54-57. In Birnik et al., Tobacco leaf samples taken at different stages of air aging at high temperatures for 24 hours at 70 ° C. will remove excess moisture and reduce microbial propagation, thus nitrite and tobacco-specific nitros It is assumed that it is possible to prevent the accumulation of amines (TSNA). Birnik et al., Table II on page 56, included some of Burton's summary data on nitrite and TSNA contents in the lamina and midrib of KY160 and KY171 samples. This document contains lyophilization and fast drying test data, but no mention is made of microwave treated specimens. In this document, page 56 has the following conclusion:

"This study concludes that heat (70 ° C) on black tobacco after cell breakdown can reduce the amount of nitrite and TSNA accumulation in the veins and veins. Rapid drying reduces the microbial activity produced by slow ripening at external temperatures. However, it should be noted that this treatment degrades the quality of tobacco leaves. "

Bairnik et al. Also describe a typical aging method of Skroniowski tobacco in Poland as an example of a two-stage aging method. This document explains that tobacco is first air-aged, and when the leaf veins turn yellow or brown, the tobacco is heated to 65 ° C. for 2 days to ripen the stems. Analysis of cigarettes prepared in this manner revealed that both the nitrite and TSNA amounts were lowered to less than 10 μg / g and 0.6 to 2.1 μg / g, respectively. Bairnk et al. Theorized that these results could be explained by the rapid heating that prevents the bacteria from further breeding. However, Bairnik et al. Found that less than 15 μg / g nitrite and 0.2 μg / g TSNA, which had low amounts of nitrite and TSNA, were also obtained for air-aged tobacco in Poland.

<Overview of invention>

One object of the present invention is to substantially remove or reduce nitrosamines in tobacco for consumption by smoking or by other means.

Another object of the present invention is to reduce the carcinogenic potential of cigarettes, cigarettes, chewing tobacco, snuff, and tobacco products including tobacco containing gums and lozenges.

Another object of the present invention is to provide N'-nitrosonornicotine (NNN), 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK), Substantially eliminating or significantly reducing the amount of tobacco-specific nitrosamines, including N'-nitrosoanathabin (NAT) and N'-nitrosoanabasin (NAB).

It is another object of the present invention to treat tobacco that has not matured at a suitable time after harvest to undergo the aging process without adversely affecting tobacco suitability for human consumption.

Another object of the present invention is to reduce the content of tobacco specific nitrosamines in fully aged tobacco.

It is yet another object of the present invention to provide tobacco products suitable for human consumption which substantially reduce the amount of tobacco-specific nitrosamines, thereby lowering the carcinogenic potential of such products, thereby smoking, consuming some types of tobacco or To reduce the content of tobacco-specific nitrosamines, in particular NNN and NNK, and their metabolites, in humans otherwise consumed. Cigarette products are preferably cigarettes, cigar cigarettes, chewing tobacco, or tobacco-containing gums or lozenges.

The above and other objects and advantages of the present invention reduce the amount of one or more nitrosamines in at least a portion of an unmatured plant that is in a state that is likely to reduce the amount of nitrosamines or prevent the formation of nitrosamines. Or by reducing the amount of nitrosamines in the harvested tobacco plants or preventing the formation of nitrosamines in the harvested tobacco plants.

In the process of the invention, the microwave treatment step is preferably carried out on tobacco leaves or parts thereof after the leaves start to turn yellow and before the tobacco-specific nitrosamine accumulates significantly. In addition, the microwave treatment step in the method of the present invention is preferably carried out before the cell integrity of the leaves is significantly lost.

In another preferred embodiment of the present invention, the tobacco is flu tobacco and the microwave treatment step is performed within about 24 to about 72 hours of harvest, even more preferably within about 24 to about 36 hours of harvest.

In another embodiment of the present invention, harvested tobacco is placed under said external temperature conditions in a controlled environment prior to microwave treatment.

A preferred aspect of the present invention is to make the tobacco leaves with stems to be dried more uniformly by the microwave device by performing the step of squeezing excess moisture by physically compressing the leaves before microwave treatment. This step can be conveniently performed by passing the leaves through a pair of properly spaced rotating cylindrical rollers before entering the microwave zone.

In another preferred embodiment of the invention, the microwaves have a period of about 900 to about 2500 MHz and the plant is irradiated for at least about 1 second, preferably from about 10 seconds to about 5 minutes, at a given output. The output figures used generally determine the length of time that a cigarette should be irradiated to microwaves, ranging from about 600 to about 1000 watts using conventional household microwave ovens, and hundreds of kilowatts or more using commercial multimode irradiators. Can be until. When using an irradiator designed to handle one leaf, the output value is preferably from about 2 to about 75 kilowatts, more preferably from about 5 to about 50 kilowatts allowing the treatment to be carried out relatively quickly.

It is also preferred in accordance with the present invention to microwave the leaves or portions thereof for a time sufficient to effectively dry them without burning them, making them suitable for human consumption.

The present invention is also prepared by microwave treatment of tobacco leaves N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrosoanathabin And natural accumulation of one or more tobacco-specific nitrosamines, such as N'-nitrosoanabasin.

In its broadest form, the present invention also includes non-green tobacco suitable for human consumption and includes tobacco products in which the content of one or more tobacco-specific nitrosamines is lower than that of conventionally aged tobacco.

In a preferred embodiment, the non-green tobacco product has a TSNA (NNN, NNK, NAB and NAT) of less than 0.2 μg / g, more preferably less than about 0.15 μg / g, even more preferably less than about 0.1 μg / g. Content, less than about 0.15 μg / g, more preferably less than about 0.10 μg / g, even more preferably less than about 0.05 μg / g, and less than about 0.002 μg / g, more preferably about 0.001 μg It has an NNK content of less than / g, even more preferably less than about 0.005 μg / g.

The present invention also relates to tobacco products comprising dried yellow tobacco suitable for human consumption, wherein the content of one or more tobacco-specific nitrosamines is lower compared to tobacco which is typically aged. In a preferred embodiment, the yellow tobacco product has a TSNA (NNN, NNK, NAB and NAT) content, NNN content and NNK content within the above preferred ranges.

In another embodiment, a non-green or yellow tobacco product has a human whose TSNA (NNN, NNK, NAB and NAT) content is within about 25% by weight of the TSNA content in freshly harvested green tobacco harvests from which the product was sourced. This includes cigarettes that are not green or yellow suitable for consumption. Tobacco products that are not green or yellow have essentially no more than about 10% by weight of TSNA, more preferably about 5% by weight, and most preferably the content of TSNA in freshly harvested tobacco crops that were the source of the product. More preferably (eg, within a few percent by weight). Cigarette products that are not green or yellow have a content of at least one TSNA of NNN, NNK, NAB and NAT within about 25% by weight, preferably within about 10% by weight, more preferably within about 5% by weight, Preferably cigarettes that are not green or yellow, suitable for human consumption, that are intrinsically close to (e.g., within a few percent by weight) of TSNA or the content of TSNAs corresponding to the freshly harvested green tobacco harvest that was the source of the product. It is also preferred to include.

In another embodiment of the invention, a non-green or yellow tobacco product has a microwave treatment designed to lower the TSNA content although the TSNA (NNN, NNK, NAB and NAT) content is made from the same tobacco harvest as the product of the invention. Or at least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, most preferably of the content of TSNA in the same type of tobacco product aged without the use of other techniques. Cigarettes that are not green or yellow that are suitable for human consumption, at least about 99% by weight. Tobacco products that are not green or yellow use microwave treatment or other techniques designed to reduce the TSNA content, although the content of one or more TSNAs of NNN, NNK, NAB and NAT is made from the same tobacco harvest as the products of the present invention. At least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, most preferably about 99 than the content of at least one TSNA in the same type of tobacco product aged without It is also desirable to include cigarettes that are not more than green or yellow suitable for human consumption, at least by weight percent.

A preferred form of the invention is that the content of at least one tobacco specific nitrosamine produced by a process comprising microwave treatment of unaged tobacco which is susceptible to formation of at least one tobacco specific nitrosamine is A tobacco product comprising reduced tobacco.

In another embodiment, the present invention relates to one type of mature brown tobacco comprising rehydrating the matured brown tobacco, and microwave treating the rehydrated tobacco at a predetermined energy level for a predetermined time. The present invention relates to a method for reducing the content of nitrosamine peculiar to tobacco.

Similarly, the present invention is directed to a mature brown tobacco prepared by a process comprising the step of rehydrating the mature brown tobacco, and microwave processing the rehydrated tobacco at a predetermined energy level for a predetermined time. Tobacco products comprising aged brown tobacco having a reduced content of at least one tobacco specific nitrosamine are within the scope of the present invention.

In another embodiment of the present invention, the present invention provides a method for reducing the amount of tobacco-specific nitrosamines or reducing the amount of unripened harvested tobacco leaves on leaves that are susceptible to the formation of tobacco-specific nitrosamines. Microwave treatment, comprising: microwave treatment for a time sufficient to reduce or substantially prevent the formation of nitrosamines unique to species or tobacco, and to mold tobacco products comprising microwave treated leaves And a tobacco product selected from chewing tobacco, snuff, and tobacco containing gums and lozenges.

In addition, as described above with respect to an embodiment using microwaves, the radiation in the form of electromagnetic waves having a higher frequency and shorter wavelength than the microwave region described above and described in detail below, the cigarette in the form of electromagnetic energy at the same time after harvesting. It has been found that treatment can be used to achieve reducing or substantially eliminating TSNA in tobacco products, which is a primary object of the present invention. Accordingly, the present invention also relates to reducing or substantially reducing the amount of one or more nitrosamines in at least a portion of an unmatured plant that is in a state that is likely to reduce the amount of nitrosamines or prevent the formation of nitrosamines. A method of reducing or preventing the formation of nitrosamines in harvested tobacco plants, comprising treatment with radiation higher in frequency than the microwave region for a time sufficient to prevent it.

As in the embodiment using microwaves, the method of the present invention involves radiation of a higher frequency than the microwave region on the tobacco leaf or a portion thereof after the leaf begins to turn yellow and before the tobacco-specific nitrosamines in the leaf accumulate significantly. It is preferable to carry out the processing step. In the method of the invention, it is also preferred to carry out the step of treatment with such radiation before the cellular integrity of the leaves is considerably lost. Preferred energy sources capable of producing such radiation are further described below, examples of which are far infrared and infrared, UV (ultraviolet), soft x-rays or lasers, accelerated particle beams (eg electron beams), x-rays And gamma rays.

<Brief Description of Drawings>

1 is a photograph showing a "yellow" Virginia flu cigarette 24 to 72 hours after harvest. Figure 2 shows a photograph of a microwave treated low nitrosamine "yellow" Virginia flu cigarette in accordance with the present invention. 3 is a side perspective view illustration of a portion of a commercial size mobile microwave irradiator that may be used to perform microwave processing in accordance with the present invention.

The present invention relates to a method of treating tobacco to reduce the content of harmful nitrosamines normally found in tobacco or to prevent the formation of nitrosamines. The present invention also relates to tobacco products having a low content of nitrosamines.

<Reference to Related Application>

This application is a partial continuing application of Application No. 08 / 879,905, filed June 20, 1997, which is a partial continuing application of Application No. 08 / 757,104, filed December 2, 1996. Is a partial continuing application of Application No. 08 / 739,942, filed October 30, 1996, which is now abandoned, which is a partial continuing application of Application No. 08 / 671,718, filed June 28, 1996. The above-mentioned applications, except for this application, and Application No. 08 / 671,718, filed June 28, 1996, claim priority to Provisional Application No. 60 / 023,205, filed August 5, 1996.

Always take into account factors such as varietal differences, differences in leaves harvested at various positions of the stem, differences between ripening lights used, and environmental changes over a single season or several seasons, especially in the case of air ripening. Because the maturation conditions must be controlled, tobacco ripening is a technology rather than a science. For example, the practice of influenza aging is to some extent empirical and best performed by humans who have experience in this field over a significant period of time. See, eg, Peele et al., "Chemical and Biochemical Changes During The Flue Curing Of Tobacco," Recent Advances In Tobacco Science, Vol. 21, pp. See below, Symposium Proceedings 49th Meeting Chemists' Research Conference, September 24-27, 1995, Lexington, Kentucky, hereinafter referred to as "Peel et al.". Therefore, those skilled in the art of tobacco ripening will understand that the broadest form of external parameters of the present invention may vary to some extent depending upon the exact point of confluence of the elements for any given harvest.

In another preferred embodiment, the present invention has found that there is a time limit for treating tobacco in a manner that will substantially prevent TSNA formation during the tobacco ripening cycle. Of course, the exact time period for which TSNA formation is effectively excluded or substantially reduced depends on the type of tobacco, the method of aging, and various variables, including those mentioned above. According to this preferred embodiment of the invention, the time period corresponds to the period after harvest, after which the leaves are freshly harvested or "green" and before TSNA and / or nitrite accumulate in the leaves in equivalent amounts, which period This is typically the period during which leaves undergo a yellowing process or become yellow before they turn brown and noticeably lose their cell integrity. Unless otherwise stated from the context, the terms "substantial" and "fairly significant" as used herein generally refer to prevailing or pluralities in terms of relative scale, even though there are some differences. During this period, the tobacco may be microwave treated at a predetermined energy level for a predetermined time, as further described below, to substantially prevent the formation of TSNA in the leaves or to reduce the content of any already formed TSNA. This microwave treatment essentially inhibits the natural formation of TSNA and provides dried yellowish yellow leaves suitable for human consumption. If the TSNA has already begun to substantially accumulate, usually at the end of the yellow state, the application of microwave energy to the leaves according to the invention effectively stops the natural TSNA formation cycle, preventing further formation of large amounts of TSNA. do. When tobacco that is yellow or sulfiding is processed in this manner at the optimal time of the ripening cycle, the tobacco product obtained has a TSNA amount substantially similar to that of freshly harvested green tobacco while maintaining its aroma and taste.

In another embodiment, the present invention provides a treatment of aged (brown) tobacco that effectively reduces the TSNA content of the matured tobacco by rehydrating the aged tobacco and microwave treating the rehydrated matured tobacco as further described below. It is about.

The present invention is applicable to the treatment of harvested tobacco intended for human consumption. Numerous studies have been carried out on tobacco, in particular on nitrosamines specific to tobacco. Freshly harvested tobacco leaves are called "green tobacco" and contain no known carcinogenic substances, but green tobacco is not suitable for human consumption. The method of ripening green tobacco depends on the type of tobacco harvested. For example, Virginia influenza (bright) cigarettes are typically flu ripened, while Burley and certain darker strains are usually air aged. Flu ripening of tobacco typically occurs over a period of 5 to 7 days compared to 1 to 2 months or more of air ripening. According to Phil et al., Flu ripening is generally divided into three stages: sulfidation (35-40 ° C.) for about 36-72 hours (other studies report that sulphide is about 36 hours before, for example, for certain Virginia flu strains). Reported to start after 24 hours), leaf drying for 48 hours (40-57 ° C.), and vein (stem) drying for 48 hours (57-75 ° C.). Various major chemical and biochemical changes begin during the sulfidation phase and continue through the initial state of leaf drying.

In a typical flu aging method, the sulfidation step is performed on light. In this state, the green leaves gradually lose color due to chlorophyll decomposition, correspondingly the appearance of a yellow carotenoid pigment. According to Phil et al., The external air outlet of light is blocked and the temperature is maintained at approximately 35-37 ° C. to carry out the sulfidation of flu-aged tobacco. This method uses a controlled environment, maintains a relative humidity of approximately 85% in light, limits water loss from leaves, and allows leaves to continue metabolic processes initiated in the field. The operator constantly monitors the progress of ripening by observing the reduction in chlorophyll and green from the leaves and the color progression to the desired lemon to golden orange leaves.

For one particular Virginia influenza variety tested as disclosed herein, freshly harvested green tobacco can be grown 24-48 at about 37.8 to 43.3 ° C. (about 100-110 ° F.) until the leaves turn completely yellow. Place in the light for hours. Yellow tobacco has a reduced moisture content, ie about 90% by weight when green and about 70-40% by weight when yellow. At this stage, yellow tobacco is essentially free of carcinogens and the TSNA content is substantially the same as freshly harvested green tobacco. This Virginia flu tobacco typically is in the yellow phase for about 6-7 days after which the leaves turn from yellow to brown. Brown Virginia flu tobacco typically has a moisture content of about 11 to about 15 weight percent. Tobacco conversion from yellow to brown results in the formation and substantial accumulation of nitrosamines and elevated microbial content. The exact mechanism by which tobacco-specific nitrosamines are formed is not clear, but it is believed that microbial nitrate reductase is involved in the production of nitrite during the aging process and is enhanced by microbial activity.

Tobacco-specific nitrosamines are believed to be formed under acidic conditions by the reaction of amines with nitrified species derived from nitrite, such as NO ₂ , N ₂ O ₃ and N ₂ O ₄ . Bairnik et al. Discussed the formation of TSNA assumed in pp 43-45, an overview of which is outlined below.

Tobacco leaves contain abundant amines in the form of amino acids, proteins and alkaloids. Nicotine, the tertiary amine (referred to as (1) in the table below), is the main alkaloid of tobacco, while other nicotinic alkaloids are the secondary amines, nornicotine (2), anatabin (3), and anabacin (4). )to be. Tobacco also generally contains up to 5% nitrate and trace amounts of nitrite.

Nitrosolation of nornicotine (2), anatabin (3), and anabacin (4) results in the corresponding nitrosamines: N'-nitrosonornicotin (NNN, 5), N'-nitrosoanatabin (NAT). , 6), and N'-nitrosonavacin (NAB, 7). When nicotine (1) in the aqueous solution is nitrosified, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK, 8) (NNN, 5) and 4- (N- A mixture of nitrosomethylamino) -4- (3-pyridyl) -1-butanal (NNA, 9) is obtained. Less commonly seen TSNAs are NNAL (4-nitrosomethylamino) -1- (3-pyridyl) -1-butanol, 10), iso-NNAL (4-N-nitrosomethylamino) -4- (3-pyridyl) -1-butanol, 11) and iso-NNAC (4- (N-nitrosomethylamino) -4- (pyridyl) -butanoic acid, 12). The formation of such TSNA from the corresponding tobacco alkaloids is shown in the following scheme using the designations 1-12 above (above page 44 of Bairn et al.).

At present, green freshly harvested tobacco contains virtually no nitrite or TSNA, and it is generally agreed that these compounds are produced upon ripening and storage of tobacco. Research has been undertaken over the last few decades to identify the reactions associated with TSNA formation in tobacco ripening and several important factors have been identified. These include plant genotypes, plant maturity at harvest time, ripening conditions and microbial activity.

Studies have shown that nitrite and TSNA begin after the end of sulfidation in air ripening and the leaves turn completely brown, e.g. 2-3 weeks after harvest for certain air-aged strains, and after harvest in flu-aged varieties. Approximately one week later, it appears to accumulate in the ending period. This is the time when cell integrity is lost due to water loss and leakage of cell contents into the intercellular space. Therefore, during air ripening, there is a short period of time during which cells collapse and microorganisms can nourish. Byrnik et al. Suggested that nitrites may accumulate substantially as a result of nitrate reduction by catabolization, thereby enabling the formation of TSNA.

As cited in Baynik et al., There are few published reports on the effect of microflora on tobacco leaves and aged tobacco during growth and ripening. However, it is assumed that the microbial nitrite reductase is involved in the production of nitrate upon aging. If the cell structure is destroyed after the yellow state and the invading microorganisms have access to the nutrients, they can produce nitrite under favorable conditions of high humidity, optimum temperature and absence of oxygen. The "duration" during which water activity is still high enough and the cellular structure collapses is usually quite short.

According to the present invention, the formation of TSNA in tobacco is substantially prevented or prevented by microwave treatment of harvested leaves under the conditions described herein. In a preferred embodiment, tobacco leaves are exposed to microwave energy at the point between the onset of sulfidation and the substantial loss of cell integrity. For optimal results, it is desirable to pass the harvested leaves through the microwave field as a single leaf rather than a pile or large number of leaves. Treatment of the leaves in this manner has been found to completely or substantially prevent the formation of tobacco specific nitrosamines, including the known carcinogens NNN and NNK.

According to a preferred embodiment of the invention, a tobacco product which is suitable for human consumption and which has a lower content of at least one tobacco-specific nitrosamine than tobacco which has been aged in a conventional manner, is non-green and / or yellow. Green, or freshly harvested tobacco is generally unsuitable for human consumption, as mentioned above. As used herein, "non-green" is that tobacco has lost at least most of the chlorophyll, including but not limited to partially yellow leaves, leaves that are completely yellow, and leaves that begin to turn brown. In a preferred embodiment, the non-green tobacco product has a TSNA (NNN, NNK, NAB and NAT) content of less than 0.2 μg / g, more preferably less than about 0.15 μg / g, even more preferably about 0.1 μg. less than / g, NNN content is less than about 0.15 μg / g, more preferably less than about 0.10 μg / g, most preferably less than about 0.05 μg / g, and NNK content is less than about 0.002 μg / g Less, more preferably less than 0.001 μg / g, most preferably less than about 0.0005 μg / g. Given the values of factors that may affect TSNA formation of tobacco as mentioned above, those skilled in the art will understand that these values are not absolute and are in the preferred range.

The present invention relates to tobacco products comprising dried yellow tobacco suitable for human consumption and having a lower content of at least one tobacco specific nitrosamine than tobacco aged in a conventional manner. In a preferred embodiment, the yellow tobacco product has a TSNA (NNN, NNK, NAB and NAT) content, NNN content, and NNK content within the above preferred ranges.

In another embodiment, a tobacco product that is not green or yellow is suitable for human consumption and has about 25 weights of this TSNA content in freshly harvested green tobacco crops whose TSNA (NNN, NNK, NAB and NAT) content was the source of the product. Includes non-green or yellow cigarettes within%. Tobacco products that are not green or yellow have a TSNA content within about 10% by weight, more preferably within about 5% by weight, and most preferably essentially close to the TSNA content in the freshly harvested tobacco harvest that was the source of the product. (E.g., in an amount range of up to several percent by weight). For example, the present invention allows tobacco products having a TSNA content in the above ranges in amounts, whereas tobacco normally aged from the same harvest usually produces several times the amount of TSNA in freshly harvested tobacco. The present invention effectively guards the low amounts of nitrosamines found in freshly harvested green tobacco. Non-green or yellow tobacco products are suitable for human consumption and have at least about 25% by weight, preferably less than about 10% by weight, more preferably about 5% by weight, of at least one TSNA selected from NNN, NNK, NAB and NAT. Not green or yellow, in percent (e.g., in an amount range of up to several percent by weight) essentially close to the content of the corresponding TSNA or TSNAs of the freshly harvested green tobacco harvest that was most preferably the source of the product. It is also preferable to include tobacco. In other words, the content of NNN in the tobacco of the present invention is in the above range compared to the amount of NNN in freshly harvested green tobacco, or the amount of NNN + NNK in the tobacco of the present invention is compared with the amount of NNN + NNK in freshly harvested green tobacco. By the above range. In making this comparison, freshly harvested green tobacco is analyzed for TSNA content, preferably within about 24 hours of harvest.

In another embodiment of the present invention, tobacco products that are not green or yellow are suitable for human consumption and have a TSNA (NNN, NNK, NAB and NAT) content made from the same tobacco harvest as the products of the present invention. At least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight of the TSNA content of the same type of tobacco product aged without specially designed microwave treatment or other steps to lower the TSNA content, Most preferably, cigarettes that are not green or yellow are at least about 99% by weight. Cigarette products that are not green or yellow are suitable for human consumption, and although the content of one or more of TSNAs selected from NNN, NNK, NAB and NAT is made from the same tobacco harvest as the products of the present invention, At least about 75% by weight, preferably at least about 90% by weight, more preferably, than the content of the corresponding TSNA or TSNAs of the same type of tobacco product (eg, comparing cigarettes with other cigarettes) aged without microwave treatment or other techniques Also includes tobacco that is not green or yellow, which is at least about 95% by weight, most preferably at least about 99% by weight. In this embodiment, the TSNA weight percent comparison is, for example, aged by conventional means without microwave treatment from cigarettes made using dried yellow tobacco according to the invention, and from the same harvest from which the dried yellow tobacco was made. Cigarettes made from cigarettes can be used to compare TSNA weight percent.

The yellow step, where microwave treatment of the tobacco leaves is preferably carried out, is carried out by (a) examining the color of the leaves and (b) observing the percent conversion of chlorophyll to sugar when the green color turns substantially yellow, or (c) Typically observe the onset of nitrite formation or nitrosamine production occurring concurrently with the end of the yellow phase, or (d) measuring the moisture content of the leaves, for example their moisture content of about 40 to about 70 weight percent May be generally defined by any one of the methods. When microwave irradiation is applied to green tobacco, no inhibition or prevention of nitrosamine formation is observed. However, when applying microwave energy after the onset of sulfidation and before loss of cell integrity or substantial accumulation of TSNA in the leaves, the reduction in the amount of nitrosamines observed or the prevention of nitrosamine formation is shown in the data mentioned below. It is dramatic and unexpected.

The optimal time for microwave treatment of harvested tobacco during the yellow phase depends on a number of factors, including breed differences, environmental changes, and the like. Therefore, one of ordinary skill in the art can start at the onset of sulfidation (e.g., defined as the loss of most of the green color in the leaves) and until the time when the leaves lose substantial cell integrity (when they turn brown). The optimal time to perform microwave treatment on a given variety of cigarettes can be determined. For example, for a given genotype, sample leaves may be tested according to the procedures disclosed herein to determine nitrite or TSNA content, to identify relative time points at which significant TSNA accumulation begins in a given ripening cycle, or to lose cell integrity. Check the transition state that occurs. Although microwave treatment of the leaves prior to significant TSNA accumulation is the most preferred form of the method of the present invention, the principles of the present invention are at the stage of forming a significant amount of TSNA and applied to tobacco leaves with a significant amount of TSNA already accumulated. You may. If the microwave treatment is carried out in the latter step, further formation of TSNA can be effectively prevented. However, when the leaves are fully matured, the TSNA amount is essentially stabilized already, and the application of microwave irradiation is ineffective in reducing the TSNA content except under the rehydration conditions described below.

Upon microwave treatment in accordance with the present invention, the moisture content of tobacco leaves is generally reduced. That is, less than about 10% by weight, often about 5% by weight. If desired, the leaves may be rehydrated to a range of moisture typical of brown, mature tobacco (eg, Virginia flu about 11-15%) prior to making tobacco products such as cigarettes.

The present invention can be applied to all types of tobacco including flu or bright varieties, burley varieties, dark varieties, oriental / turkish varieties and the like. Within the guidelines described herein, those skilled in the art can determine the most effective time to perform the microwave step in the maturation cycle to achieve the objects and advantages of the present invention.

Preferred embodiments of the method of the present invention preferably comprise physically compacting the leaves to squeeze excess moisture from the leaves prior to microwave treatment of tobacco leaves comprising the stems to ensure more uniform drying by the microwave unit. do. This step is conveniently performed by passing the leaves through a pair of properly spaced rotating cylindrical rollers before entering the microwave zone. This compacting step helps to squeeze out moisture from the stems, and to a lesser extent the main and large leaf veins, and enables a better and evenly dried product. The rollers may be made of hard rubber, plastic or steel, may be of any desired length, and may preferably be positioned with a clearance of about 1/8 inch to 1/4 inch, although the distance may preferably vary. It is chosen to accommodate the thickness of a single leaf. The roller may be a belt or chain driven by a suitably selected motor. As will be apparent to those skilled in the art, in addition to rotating rollers, other types of squeezing or pressing means can be used for the same result.

The preferred embodiment described above of compacting leaves allows for faster production because the stem does not need to be cut and removed and the microwave time can be shortened. This embodiment is particularly advantageous for tobacco leaves intended for use in cigarettes, which usually contain some tobacco stems as part of the mixture. Alternatively, the compacting step may optionally be omitted in applications where the stem is cut off from the leaves and discarded.

In another embodiment, instead of compressing the leaves or cutting off the stems, the leaves may be steamed before applying the microwaves. As in the compacting step, steaming the entire leaf, including the stem, is described as more evenly distributing moisture to the stem and large leaf veins to allow more uniform drying of the entire leaf when applying microwaves. As a result, when this particular technique is used, whole leaves containing stems can be used in tobacco products. Details will be apparent to those skilled in the art, but successful results are obtained when the leaves are placed in a suitable steam container for a time sufficient to allow the leaves to be somewhat soft and flexible, typically from about 30 seconds to about 5 minutes.

The principles of the present invention can be applied to brown or already aged tobacco when rehydrated. In this case, although a significant and unexpected decrease in the amount of TSNA, especially NNN and NNK, is observed upon microwave treatment of rehydrated brown tobacco, the result is that before the time for the present invention to accumulate a significant amount of TSNA or nitrite in the leaves, However, it is not as dramatic as it is when applied to unmature yellow tobacco. Nevertheless, adding moisture to the aged leaves, such as by spraying the leaves with sufficient water to effectively wet the leaves, followed by microwave treatment of the rehydrated leaves, reduces the TSNA content as described in the following examples.

As mentioned above, microwave treatment alone has little effect on the nitrosamine content when treating aged or brown tobacco. However, rehydrating aged tobacco prior to microwave treatment facilitates the activity of microwave energy to reduce nitrosamines. In a preferred embodiment, the aged tobacco product is rehydrated by being added directly to the leaves in an appropriate amount of water, generally at least about 10% by weight, up to the maximum absorbent capacity. Microwave treatment of rehydrated leaves in the same manner as described for tobacco that has not been matured herein results in a decrease in nitrosamine content as shown below. The leaves may be wet in any suitable way. If the aged tobacco is in a non-leaf form, such as reconstituted "sheet" tobacco, it may be similarly rehydrated and microwaved, for example, with 10-70% by weight of water. Suitable microwave treatment conditions may be selected depending on the extent to which the leaves are rewet, but are typically within the parameter ranges mentioned above for the microwave treatment of yellow tobacco.

In accordance with the present invention, microwave treatment of rehydrated brown tobacco preferably results in a TSNA (NNN, NNK NAB and NAT) content, measured individually or collectively, about the amount of TSNA contained in the aged brown tobacco prior to rehydration. It may be reduced by at least 25% by weight, preferably at least about 35% by weight, more preferably at least about 50% by weight.

As used herein, the term “microwave treatment” refers to electromagnetic energy, which is in the form of microwaves, typically having frequencies and wavelengths that are believed to fall within the microwave region. The term “microwave” generally refers to the portion of the electromagnetic spectrum that lies between the far infrared region and the typical radio frequency spectrum. Microwaves range from approximately 1 mm wavelength and approximately 300,000 MHz in frequency to just under 30 cm and approximately 1,000 MHz in frequency. The present invention typically uses the application of a powerful microwave, preferably at the lower end of this frequency range. Within this preferred frequency range, there is a fundamental difference between heating methods by traditional methods such as microwave and infrared (eg in cooking). Because of the greater penetration, microwaves generally heat up quickly to a few cm depth, while heating by infrared radiation is much more surface area.

In the United States, commercial microwave devices such as home microwave ovens are available at standard frequencies of approximately 915 MHz and 2450 MHz, respectively. These frequencies are the standard industrial bands. In Europe, microwave frequencies of 2450 and 896 MHz are commonly used. However, under properly balanced conditions, microwaves of different frequencies and wavelengths will be useful to achieve the objects and advantages of the present invention.

Microwave energy can be generated at various power levels, depending on the intended use. Microwaves are typically generated by the Marknetron at 600-1000 watts (typically about 800 watts) of power level for typical household-level microwave devices, but commercial units typically add about 1 kW of module power. It can generate power up to several hundred kW. The magnetron can suitably be a high frequency pulse or generate a continuous wave.

The device (or oven) is the necessary link between the microwave output generator and the material to be heated. For the purposes of the present invention, any desired device may be used so long as it is adapted to allow the tobacco plant portion to be effectively radiated. The device should be in harmony with the microwave generator to optimize power transfer and to exclude energy leakage to the outside. For large samples, multimode zones (microwave ovens) can be useful if their dimensions can be larger than several times the wavelength. In order to ensure even heating of the leaves, the device may be equipped with a moving table surface such as a mode stirrer (metallic moving device which continuously changes the field distribution) and a conveyor belt. Best results are obtained by microwave treatment of the leaves to a single fold thickness rather than to a pile or bulk.

In a preferred embodiment of the invention, the microwave processing conditions include microwave frequencies from about 900 MHz to about 2500 MHz, more preferably from 915 MHz to about 2450 MHz, output levels from about 600 W to 300 Hz, for home-use devices. Is about 600 to about 1000 W, about 2 to about 75 Hz, more preferably about 5 to about 50 Hz for industrial multi-mode devices. The heating time is typically at least about 1 second, more typically from about 10 seconds to about 5 minutes. At an output of about 800 to 1000 W, the heating time is preferably from about 1 minute to about 2½ minutes when treated with a single leaf, not a pile or large quantities. When treated with a single leaf, not a pile or large quantities, for example, the heating time of a commercial scale instrument using a high power of 2 to 75 kW ranges from about 5 seconds to about 60 seconds, typically 10 to 30 seconds at 50 kPa. Will be shorter to the level. Of course, those skilled in the art will appreciate that for any given device, the optimal microwave field density can be determined based on the volume of the treatment space, the power used, and the amount of water in the leaves. Typically, using high power will shorten the time to microwave the leaves.

However, the above mentioned conditions are not absolute and in the context of the present invention, those skilled in the art will be able to determine appropriate microwave parameters. Microwave radiation is applied to the leaf or part thereof for a time sufficient to effectively dry without burning the leaf so that it is suitable for human consumption. It is also desirable to use microwave radiation at a power and time sufficient to reduce the moisture content to less than about 20 weight percent, more preferably less than about 10 weight percent, on the leaves or portions thereof.

An embodiment of a microwave irradiator of typical scale is shown in partial perspective in FIG. 3. In particular, four modular oven processing spaces with a movable transport frame 2 (not shown the right front end of the drawing) and a single wall structure (suitably made of 3003H14 aluminum) inside (each processing space is approximately 16 'long in width) A MicroDry 300 Hz microwave tobacco drying apparatus 1 comprising a conveyor microwave oven 3 having a height of 84 "x 48" is shown. Each treatment space is equipped with four doors, two on each side. The doors are double interlocked to prevent accidental irradiation of microwave energy.

3 shows an automatic cutting device 5 with multiple (eg, 12) rotating blades for removing the stem from the leaf 4. The cutter may be a straight strip about 3.4 "wide below the center of the manually fed blade. If necessary, a suitable safety device may be provided to prevent the operator's hand from being inserted. As noted above, as mentioned above, the whole leaf can be used according to another embodiment of the present invention, so instead of a cutting device, a steaming vessel or a pair of rollers can be used to squeeze moisture from the leaf in the device.

In FIG. 3, after the stem cutting operation, the cut tobacco leaves 6 are transported by the belt conveyor 7 to the main microwave oven 3 with four processing spaces. In one embodiment, the oven length of this device is about 78 feet. Introduced into the oven, the conveyor system comprises multiple, for example variable speed polypropylene belts, arranged such that the alternately cut stems fall through a pair of belts into a hopper (not shown) located beneath the belt. can do. The belt then passes the cut tobacco leaves through one of two traps, one located in each processing space designed to receive microwave energy, into each of the selected processing spaces where each leaf is microwaved in accordance with the principles of the present invention mentioned above. Will transport. After the microwave treatment, the leaves are transported by the conveyor through the treatment space outlet, the oven discharge trap, and out of the oven, and then to a suitable container for further processing to be performed.

In order to remove the moist air from the process space and the oven, an exhaust device comprising a suitable blower for recirculating the air may be included in the treatment device (moisture exhaust bin, see item 8 representatively shown in FIG. 3). In addition, if necessary, the temperature in the oven is controlled by means of a suitable spaced air convection heating source to allow the inside of the oven outside the microwave treatment space to be moved to a conveyor at a desired constant temperature, for example, 71.1 to 82.2 ° C. (160 To 180 ° F.). In mobile devices such as those shown in FIG. 3 for outdoor use, the electrical requirements can be met with a pair of conventional diesel-powered oscillators 9 and 10. Of course, if desired, the microwave drying apparatus can also be operated in a fixed position by powering a conventional power source.

Each of the four processing spaces in the oven 3 of FIG. 3 is supplied with microwave energy from a corresponding Microdry Model IV-75 microwave output source. Microwave energy is introduced into each treatment space through the splitter and through two outlets located at the top of each treatment space. A mode stirrer is placed below the outlet in each treatment space to help dissipate microwave energy. Each microwave output unit is a fully integrated processing space with the components needed to operate a 75 kW magnetron. The controller of the microwave output is located in the processing space. The unit is designed to operate continuously in an industrial environment without any intervention. Each microwave output oscillator may be located in or away from each processing space. However, if the distance is 50 ', the transmission line loss will be about 2%. Each output oscillator provides adjustable microwave energy for industrial operation. The output can be adjusted from 0 to about 75 Hz at FCC specified frequency of 915 MHz and controlled by solid state control circuit which is manually adjusted by remote control or control button on the panel with 4 to 20 Hz control signal from the process controller. do. Although the circuit is designed to adjust the output from zero, the frequency spectrum widens below about 5 kHz. The output oscillator for each processing space is a direct current power source operating an industrial magnetron that is operated and protected by circuit functions designed primarily for automatic and manual operation. The electrical function of the oscillator is monitored by an instrument on the control panel located at the door of the processing space. The instrument includes anode current, anode voltage, output, filament current, electromagnet current, and reflected power. The operation of the electric interlock function is monitored by a designated lamp located on the control panel. Each microwave output oscillator processing space is equipped with a full width door to provide maximum access to the part. The built-in electromagnetic interference shielding contents are equipped with a magnetron and associated microwave components. The door can be equipped with magnetrons and electromagnets. The system includes a circulator and water mounted in the processing space that serve as an insulator to protect the magnetron in high reflective output conditions. Microwave power oscillators use both forced draft and water to cool heat-generating components. Magnetrons and electromagnets are cooled by a closed loop demineralization system. Separate water sources and heat exchangers may be used to cool the water in this loop. In addition, a separate water source flows through the water to the air heat exchanger inside the processing space to cool the processing space air. A high pressure centrifugal blower cools the magnetron output window and the cathode structure. Water and process temperature are interlocked in the control power chain. Typical reference data for each microwave oscillator in the device is as follows:

Input (95 KVA, 440-480 VAC, 3 phase, 60 Hz), output (75 Hz at 915 ± 10 MHz), magnetron tube (CTL, CWM 75 I),

Typical magnetron operating reference data is as follows:

AC filament voltage (11.4 V), filament current (85 A), DC anode voltage (17 KV), anode current (5.0 A), DC electromagnet current (4.3 A), efficiency (80%)

In addition, conventional microwave oscillators may use a carbon steel sheath and have an output connection (WR 975 waveguide) at a suitable location at the top of the processing space.

In the throughput test, the microwave tobacco drying apparatus designed as generally described above was effective to reduce the moisture content of the leaves by at least 80%. In particular, in one measured sample, 15 pounds of leaves with an estimated initial moisture content of 85% by weight and a solids content of 15% by weight were moved through the microwave treatment space at a rate of about 180 lbs / h one leaf thickness. The weight of the leaves was measured after exiting the treatment space. Final weight is 4.6 lbs, 31% of initial weight. Thus, based on the estimated initial moisture content, 2.35 pounds of water remained in the leaves corresponding to 18.5% of the initial moisture content.

As shown in FIG. 2, treatment of the yellow tobacco with microwaves in accordance with the invention results in the formation of a dried, golden tobacco product. The data described herein show a dramatic reduction in carcinogenic nitrosamines, especially NNN and NNK, in tobacco in the unsmoked form compared to tobacco treated in a conventional manner.

Furthermore, in order to achieve the basic object of the present invention—reduction or substantial elimination of TSNA in tobacco products—agglomerates with higher frequencies and shorter wavelengths than the microwave regions mentioned above (i.e. sunlight or electro-light in the visible spectrum). It has been discovered that agglomerated electromagnetic radiation, which is distinguished from conventional exposure to, can be used to treat tobacco in the post-harvest period, approximately as mentioned above for the microwave embodiment. In other words, when using this alternative energy source, the same conventional and preferred techniques and principles mentioned above for microwave treatment can be applied. For example, tobacco is treated with this radiation at about the same time after harvest, leaves are removed from the stems, pressed between rollers or humidified before spinning.

However, although it has been found that this alternative energy source significantly and preferably reduces or substantially eliminates TSNA or inhibits its formation, any of the other embodiments tested so far are effective in drying leaves by the microwave technique described in detail. It wasn't. Thus, when using this alternative energy source, it would be desirable to combine the spinning step with subsequent oven-drying or tumble-drying steps to further process the spun tobacco leaves to complete the maturation cycle.

In particular, any electromagnetic radiation source having a higher frequency than the microwave region in the conventional electromagnetic spectrum, and an accelerated particle beam such as an electron beam, are in a state in which the tobacco is not ripe and the amount of TSNA is reduced or its formation is easy to be suppressed. Is effective to significantly reduce, substantially eliminate, and / or prevent the formation of TSNA. On a scale within the electromagnetic spectrum, where microwaves are typically defined as frequencies of 10 ¹¹ Hz and wavelengths of 3 × 10 ⁻³ m, these energy sources include frequencies of about 10 ¹² to 10 ¹⁴ Hz and 3 × 10 ⁻⁴ m to 3 × Far infrared and infrared radiation with a wavelength of 10 ^-6 m, ultraviolet radiation with a frequency of about 10 ¹⁶ to 10 ¹⁸ kHz and a wavelength of 3 × 10 ^-8 m to 3 × 10 ^-10 m, soft x-ray or laser, cathode ray (A stream of negatively charged electrons emitted perpendicularly to the surface from the cathode of the vacuum tube), including, but not limited to, x-rays and gamma radiation, which are typically characterized by having a frequency of at least 10 ²¹ Hz and a corresponding wavelength. Does not.

As will be appreciated by those skilled in the art, the more radiation delivered by an energy source, the less time is required to radiate onto the leaves to achieve the desired result. When using such high frequency radiation sources, radiation times of typically less than 1 minute, preferably less than 30 seconds, more preferably less than about 10 seconds are required. In other words, a radiation time of at least about 1 second is preferred. However, as shown in the examples below, radiation dose rates can be adjusted to deliver radiation doses for more than a specified time, if desired. For example, 1 Mrad of radiation is instantaneously (with an electron beam accelerator as described in Example 17 below) instantaneously or 1 Mrad (as illustrated by the closed chamber gamma radiation test described in Example 19 below). 10 kGrey) of radiation can be delivered at a predetermined radiation dose rate) by delivering a radiation dose rate of about 0.8 Mrad / h). When using high frequency radiation sources, it is desirable to use radiation doses that reduce the TSNA by at least 50% relative to the unaged sample. While the specific radiation dose and irradiation dose rate will depend on the particular device and the type of radiation source to be irradiated, those skilled in the art will appreciate about 0.1 to about 10 Mrad, more preferably about 0.5 to about 5 Mrad, more preferably, on tobacco samples. It will be appreciated that it is usually desirable to use radiation of about 0.75 to about 1.5 Mrad.

As described in the Examples below, tests are performed on various tobacco samples using examples of such additional radiation sources, accelerated braille beams, CO ₂ lasers and gamma radiation. In each example, it was demonstrated that the unaged, radiation treated tobacco samples had significantly reduced TSNA content and / or had been substantially removed.

Further, in another embodiment of the present invention, it has been demonstrated that the treatment of tobacco in a circulating air convection oven, while susceptible, reduces TSNA content while reducing leaf quality. Unlike conventional baking ovens, which are not very effective in lowering TSNA content and lowering the quality of tobacco, at temperatures of about 100 to about 500 ° F. in a circulating air convection oven, from 1 hour to the lowest temperature scale for about 5 minutes at the highest temperature scale. Heating can effectively reduce the content of TSNA in tobacco and inhibit its formation in the possible states described herein. More preferably, using an oven combined with circulating air convection heating and microwave irradiation can reduce the heating time while improving the quality of the leaves. For example, if only the convection oven is used, the leaf veins and stems are not completely dried during the time that the leaf veins are dried, so they are overdried and the leaf veins become broken. Combining circulating air convection oven heating with microwave treatment can improve leaf quality while providing a more uniformly dried product.

In another aspect, the present invention enables the consumption of tobacco products in which TSNA is significantly reduced or substantially eliminated, thereby reducing the content of tobacco-specific nitrosamines in the human or animal body that smokes, chews, or consumes tobacco. It is about a method of removing substantially.

It has been demonstrated herein that irradiation of unaged tobacco with microwaves or other radiation sources is effective in providing tobacco with significantly reduced nitrosamine content. This technique can be facilitated by stripping and lining the stems to 1/3 to 1/2 of the tobacco leaf length, especially when the stems are discarded to remove moisture or when the above mentioned humidification step is not used. For microwave treated tobacco leaves produced by removing the stem in this manner, the undesirable stem portion has already been removed and there is no need to use a thrasher. As a result, there is no typical loss of tobacco products associated with the threshing machine, thus reducing tobacco waste by about 10-30%.

The improved tobacco of the present invention is the overall tobacco for tobacco that is typically aged in any tobacco product, including cigarettes, cigars, chewing tobacco, tobacco chewing gums, tobacco containing tablets, tobacco wraps, snuff, or tobacco flavors and food additives. Or in part. For smoking purposes, the present invention provides a less toxic flavor while maintaining good smoking characteristics and providing complete fragrance with conventional nicotine content. For the purpose of chewing, snuff, tobacco wraps and food additives, the tobacco of the present invention has a rich and pleasant aroma.

The invention is now described with reference to the following examples, but is not intended to limit the scope of the invention in any way.

<Example 1>

Virginia flu tobacco was harvested, leaves were placed in a curing barn at about 33.8-43.3 ° C. (about 100-110 ° F.) and the flu-curing process started. After about 24 to 36 hours of harvesting, the leaves turned yellow and samples 1-3 were removed from the light. Sample 1 was a leaf vein sample, the vein was stripped off, and baked in the air convection oven at about 400 to 500 ° C. for about 1 hour until the leaf vein became brown. Sample 2 is a yellow leaf, placed in a Goldstar model MA-1572M microwave oven (2450 MHz) and heated to high power (1,000 W) while rotating for about 2½ minutes. Sample 3 is an unaged yellow leaf used as a control. Samples 4 and 5 were placed in aged light at elevated temperatures of about 82.2 ° C. (about 180 ° F.), Sample 4 dried outside the rack, and Sample 5 dried inside the rack. Sample 6 is brown leaf which has undergone the usual flu ripening process.

Each sample was analyzed to determine NNN, NAT, NAB and NNK content. In the examples, "TSNA" refers to the sum of these four tobacco-specific nitrosamines. Sampling and extraction are followed by conventional processes for analysis of TSNA (Burton et al., "Distribution of Tobacco Constituents in Tobacco Leaf Tissue. 1. Tobacco-specific Nitrosamines, Nitrate, Nitrite and Alkaloids", J Agric.Food Chem., Volume 40, No. 6, 1992), TEA connected individual TSNA to Hewlett-Packard Model 5890A gas chromatography from Thermedics. Inc. Quantification was performed on a model 543 thermal energy analyzer. The results are shown in Table 1 below. All data in each table below are expressed in μg (ie ppm or μg / g) of nitrosamine per gram of sample.

Sample number NNN NAT + NAB NNK TSNA 1-yellow grilled leaf vein 0.0310 0.843 <0.0004 0.1157 Microwave treatment to 2-yellow <0.0004 <0.0006 <0.0005 <0.0014 3-yellow counterpart 0.0451 0.1253 0.0356 0.2061 4-quickly dry outside 0.6241 1.4862 1.2248 3.3351 5- Quickly dry inside the rack 0.7465 1.5993 1.3568 3.7044 6-normal flu ripening 1.0263 1.7107 2.2534 4.9904

<Example 2>

Virginia flu tobacco was harvested. Sample 7 is freshly harvested green leaf used as a control, and Sample 8 is a 20-minute microwave irradiation of microwave radiation operated at 2.5 kHz at 2450 MHz in a microdryer's multimode microwave irradiator in Louisville, Kentucky. Harvested green leaves. Samples 9-12 were typically made from flu aged brown tobacco. Sample 9 is a cigarette formed from cigarettes, Sample 10 is an unpackaged piece of tobacco for manufacture of cigarettes, and Samples 11 and 12 are respectively sample 9 (cigarette) and 10 (except that the same microwave conditions apply as sample 8). Unpackaged tobacco). TSNA content was analyzed in the same manner as in Example 1. The results are shown in Table 2 below.

Sample number NNN NAT + NAB NNK TSNA 7-freshly harvested leaf counterparts <0.0104 0.126 0.0005 0.126 8-microwave freshly harvested leaves 0.029 0.135 0.0004 0.164 9-cigarette counterpart 1.997 3.495 2.735 8.226 10-unpacked control 2.067 3.742 2.982 8.791 11-microwave treated cigarette 2.056 3.499 2.804 8.359 12-microwave untreated cigarette 2.139 3.612 2.957 8.707

<Example 3>

Cigarette products of the following brands shown in Table 3 were randomly purchased from various retailers in Lexington, Kentucky, and analyzed for TSNA content using the method described in Example 1.

Sample number Code number NNN NAT + NAB NNK TSNA 13-Marlborough-pc 288292 3.565 4.538 1.099 9.202 14-Marlborough-pc 288292 4.146 4.992 1.142 10.279 15- Marlborough-pc 288292 3.580 4.290 1.106 8.977 16-Marlborough-pc 288292 3.849 4.748 1.130 9.728 17-Marlboro Rights 100's-bx 288192 4.604 5.662 1.223 11.489 18-Marlboro Rights 100's-pc 288182 3.471 3.859 1.211 8.541 19-Marlboro Rights 100's-pc 288182 3.488 4.136 1.074 8.698 20-Marlboro Rights 100's-pc 288182 3.566 4.240 1.164 8.970 21-winston 100's-pc 123143 2.311 2.968 1.329 6.608 22-Winston King 123103 2.241 2.850 1.256 6.348 23-winstoning-bx 125123 2.162 2.831 1.326 6.319 24-winstoning-bx 123123 2.577 3.130 1.207 6.914 25-winstoning-pc 123103 1.988 2.563 1.234 5.786 26-Winston Lights 100'-pc 123133 2.161 2.706 1.258 6.124 27-Winston Lights 100'-pc 123133 2.189 2.699 1.262 6.150 28-Winston Lights 100'-pc 123133 2.394 3.385 2.330 8.109

<Example 4>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) and the flu ripening process started. After about 24 to 26 hours of harvesting, the leaves turned yellow and then removed from the light and subjected to microwave treatment (1000 W) set to high power (1,000 W) while rotating for about 2½ minutes in a Goldstar model MA-1572M microwave oven. The leaves did not turn brown but instead remained golden but this process effectively dried them. The leaves were sliced and made into cigarettes. Samples 29-33 were taken from batch labeled Red Full Flavor and samples 34-38 were taken from batch labeled Blue Light. Samples 39-42 are natural American Spirit brand cigarettes purchased from health food stores. The TSNA content of Samples 29-42 was analyzed using the process described in Example 1 and the results are shown in Table 4 below.

Sample number 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 flavor REP 5 0.140 0.293 <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 STD in the table is the standard deviation of the mean of the samples.

Example 5

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) and the flu ripening process started. After about 24 to 36 hours of harvesting, the leaves turned yellow and samples 43 and 44 were removed from the light and microwaved at an output of about 6 Hz for about 20 to 30 seconds with the aforementioned microdry multimode irradiator. Samples 43 and 44 were dried to golden leaves after microwave treatment. Samples 45-51 were made from brown ripened leaves that had undergone the usual flu ripening process. Sample 45 is a control, Samples 46 and 47 are baked for about 1 and about 3 minutes, respectively, in a convection oven preheated to about 204.4 to 260.0 ° C. (about 400 to 500 ° F.), and Samples 48 and 49 from Microdryer Microwave radiation (915 MHz) was irradiated for about 10 and 40 seconds in waveguide irradiator model WR-975 (output setting 0-75 kW), which is a large multimode oven. Samples 50 and 51 are tobacco (reconstituted sheets) tobacco cut from flu aged leaves. Sample 50 was microwaved with waveguide microwave at 50 Hz for about 1.5 minutes, and sample 51 was baked for about 3 minutes in a convection oven preheated to 204.4 to 260.0 ° C. (400 to 500 ° F.). These samples were analyzed for TSNA content using the method described in Example 1 and the results are shown in Table 5 below.

Sample number NNN NAT + NAB NNK TSNA Microwave treatment for 43-20 seconds <0.0106 <0.1068 <0.0007 <0.1181 Microwave treatment for 44-30 seconds <0.0103 <0.1065 <0.0004 <0.1172 45-microwave untreated control 0.92 2.05 3.71 6.68 Bake in the oven for 46-1 minutes 1.14 2.41 5.10 8.66 Bake in the oven for 47-3 minutes 0.89 2.06 2.68 5.64 Microwave treatment with waveguide at 50 Hz for 48-10 seconds 1.00 2.31 3.29 6.59 Microwave treatment with waveguide at 50 Hz for 49-40 seconds 0.62 1.55 1.69 3.86 50-cut tobacco, microwave treated with waveguide at 50 μs for 1.5 min 4.22 4.91 0.99 10.12 51-cut cigarette, baked in the oven for 3 minutes 4.76 5.60 1.08 11.44

<Example 6>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Samples 52 to 55 are cigarettes made from yellow tobacco taken out of light after about 24 to 36 hours and microwaved for about 2 minutes in a Goldstar microwave oven, model MA-1572M (2450 MHz), set to high power (1000 watts). It was. For comparison, Samples 61 and 62 are cigarettes made from leaves that have undergone the normal flu ripening process, without microwave treatment. Sample 56 is the ripened leaf, Sample 57 is the yellowed, not fully matured, Sample 58 is the matured leaf vein, and Samples 59 and 60 are the matured veins. TSNA content was measured as in Example 1 and the results are shown in Table 6 below.

Sample number NNN NAT + NAB NNK TSNA 52-Gold Smoke Cigarette 0.12 0.23 0.03 0.38 53-gold smoke II, 85 mm 0.062 0.326 0.016 0.404 54-gold smoke 85mm 0.128 0.348 0.029 0.504 55-Gold Smoke 100's Specimen B 0.166 0.317 0.047 0.531 56-Sample M-M 3.269 4.751 0.833 8.853 57-Sample B-C 0.267 0.720 0.954 1.941 58-lobe 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-gold smoke counterpart 1.954 1.544 0.492 3.990 62-gold smoke counterpart 1.952 1.889 0.424 4.265

<Example 7>

Virginia flu tobacco was harvested. Samples 63 and 66 were freshly harvested, green tobacco that had not matured, but some had air aged after a week before TSNA measurements. The remaining leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Sample 68 is a leaf taken out of light after turning to yellow after about 24 to 36 hours of harvest and subjected to microwave treatment at 25 Hz for about 40 seconds with the waveguide multimode irradiator described above.

Samples 64/65 (leaves) and 67/70 (reconstituted sheet tobacco, or chopped tobacco) demonstrated the effect of the present invention on rehydrating aged tobacco, followed by irradiation of microwaves. Samples 64 and 65 are leaf specimens that have undergone the usual flu ripening process, while sample 64 is rehydrated with running tap water for about 5 to 10 seconds. The leaves absorbed significant moisture. Each of Samples 64 and 65 was then microwaved at 25 Hz for about 40 seconds in a waveguide multimode irradiator. Specimens 67 and 70 are reconstituted sheet tobacco specimens made from aged leaves. Sample 67 was rehydrated by addition of water to absorb a significant amount of water, followed by microwave treatment under the conditions described for Sample 64. Sample 70 was not microwaved. Samples 69, 71 and 72 were further aged leaf samples and used as controls. TSNA content was measured as in Example 1, and the results are shown in Table 7 below.

Sample number NNN NAT + NAB NNK TSNA 63-unaged control 0.010 0.263 0.000 0.274 64-aged, 40 seconds (wet) 0.737 1.252 1.893 3.882 65-aged, 40 seconds 0.767 1.520 2.229 4.516 66-not mature, 40 seconds 0.010 0.261 0.000 0.272 67-Mature Cut Tobacco (Wet), 40 sec 0.769 1.328 0.308 2.405 68-mature, irradiated for 40 seconds at 24 에서 on waveguide 0.051 0.244 0.014 0.308 69-aged counterpart 0.866 1.548 2.545 4.960 70-Control Cigarette 1.872 2.536 0.789 5.197 71-Control 'AL' Complete Leaf 0.230 0.606 0.746 1.582 72-SML Complete Blade 0.413 0.884 1.514 2.810

<Example 8>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Sample 73 was a leaf that turned yellow after about 24 to 36 hours of harvest and was microwaved for about 2 minutes on a Goldstar model MA-1572M set to high power. Samples 74 to 76 were flu aged in a conventional manner. Sample 74 is a matured control. Samples 75 and 76 were rehydrated as in Example 7 (Sample 64), and then each specimen was microdryed for about 20 seconds (sample 75) and about 40 seconds (sample 76), respectively, at an output reading of about 6 Hz. Microwave treatment was performed on an irradiator (2450 MHz). Samples 77-79 are reconstituted sheet tobacco prepared from flu aged leaves. Sample 77 is a control and samples 78 and 79 were rehydrated as in Example 7 (sample 67). Samples 78 and 79 were microwaved in a microdryer for about 30 seconds each, while sample 78 was placed at the bottom of the oven, while sample 79 was raised a few inches higher by placing a sheet sample on a styrofoam cup to allow for more uniform heating. It was. TSNA content was measured as in Example 1 and the results are shown in Table 8 below.

Sample number NNN NAT + NAB NNK TSNA 73-yellow / microwave treatment 0.052 0.260 <0.0004 0.313 74-A-controlled leaf, matured 1.168 1.904 1.662 4.734 75-B-20 seconds 0.791 1.705 1.115 3.611 76-C-40 seconds 0.808 1.624 1.160 3.592 77-control sheet 4.417 3.697 0.960 9.073 78-30 seconds 2.755 2.553 0.644 5.952 79-30 seconds, put on and heated 1.606 1.732 0.350 3.687

Example 9

Samples 80 and 81 are Redman chewing tobacco purchased in retail. Sample 80 is the control and Sample 81 was microwaved for about 1-2 minutes on Goldstar Model MA-1572M set to high power. Samples 82 and 83 are Scottal snuff tobacco purchased in retail. Sample 82 is the control and Sample 83 was microwaved in the same manner as in Sample 81. TSNA content was measured and the results are shown in Table 9 below.

Sample number NNN NAT + NAB NNK TSNA Chewing Tobacco Before 80-Microwave Treatment 0.712 0.927 0.975 1.713 Chewing tobacco after 81-microwave treatment 0.856 0.906 0.122 1.884 82-snuff before exposure 4.896 10.545 1.973 17.414 83-snuff after exposure 6.860 14.610 1.901 23.370

<Example 10>

To examine whether yellow tobacco accumulates TSNA over time even after microwave treatment in accordance with the present invention, samples of additional cigarettes tested in Example 4 (denoted by -A), specimens 29, 35 and 39 (control) As reported in Example 4, the TSNA content was first measured, and then the TSNA content was retested after 7 months or more. The results are shown in Table 10 below.

Sample number NNN NAT NAB NNK TSNA 29A-Red FF REP # 1 0.1109 0.1877 0.1078 0.0015 0.4079 35A-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

<Example 11>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. After about 24 to 36 hours of harvesting, the leaves turned yellow and were removed from the light and microwaved for about 2 to 2½ minutes on a Goldstar model MA-1572M set to high power. All the leaves are golden and effectively dried. Certain specimens labeled "milled" were later milled with a powdery material, eg useful as a gum, lozenge or food additive. After at least 6 months the leaves were microwaved and the TSNA content of the following samples was measured using the procedure described in Example 1. The results are shown in Table 11 below.

Sample number NNN NAT NAB NNK TSNA 84-crushed 0.0013 0.0018 0.0018 0.0015 0.0064 85-crushed 0.0469 0.0341 0.0011 0.0009 0.0831 86-crushed 0.0009 0.0582 0.0013 0.0011 0.0615 87-crushed 0.0113 0.1078 0.1078 0.0015 0.2284 88-crushed 0.0569 0.1401 0.1071 0.0009 0.3051 89-crushed 0.0109 0.1642 0.1073 0.0011 0.2835 90-crushed 0.0008 0.0011 0.0011 0.0009 0.0038 91-crushed 0.0009 0.0012 0.0012 0.0010 0.0044 92-crushed 0.0012 0.1059 0.0017 0.0014 0.1101 93-crushed 0.0013 0.0529 0.0019 0.0015 0.0576 94-crushed 0.0012 0.0613 0.0017 0.0014 0.0657 95-crushed 0.0506 0.0989 0.0013 0.0010 0.1518 96-crushed 0.0017 0.0894 0.0024 0.0019 0.0954 97-crushed 0.0012 0.0017 0.0017 0.0014 0.0061 98-crushed 0.0016 0.0023 0.0023 0.0019 0.0082 99-crushed 0.0342 0.0016 0.0016 0.0013 0.0386 100-crushed 0.0014 0.0020 0.0020 0.0016 0.0070 101-leaf 0.0013 0.0539 <0.0019 <0.0016 0.0587 102-leaf 0.0009 0.0012 <0.0012 <0.0010 0.0043 103-Torn Leaves 0.0202 0.0327 <0.0007 <0.0006 0.0542

<Example 12>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Samples 104 and 105 are leaf samples that have undergone the usual flu ripening process without microwave treatment. Sample 104 is the mature vein and sample 105 is the mature leaf vein. Sample 106 is a yellow tobacco taken from the light after the leaves turn yellow after about 24 to 36 hours of harvest. After removal from the light, the leaves were microwaved for about 2 to 2½ minutes on a Goldstar model MA-1572M set to high power. All the leaves are golden and effectively dried. Some of the dried leaves were further processed in a conventional manner for analysis to obtain tobacco extracts and labeled as sample 107. The TSNA content of Samples 104-107 was measured using the procedure described in Example 1. The results are shown in Table 12 below.

Sample number NNN NAT & NAB NNK TSNA 104-Control Vein 0.083 0.180 <0.003 0.266 105-control vein 0.928 1.367 2.613 4.908 106-microwave treated leaves <0.004 <0.006 <0.005 <0.015 107-microwave treated extract <0.004 <0.005 <0.004 <0.013

Example 13

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Specimens 108 and 109 are leaf specimens that have undergone the usual flu ripening process. Sample 108 is a matured leaf vein and sample 109 is a matured vein. Samples 110 and 111 are yellow tobacco taken out of the light after the leaves turned yellow after about 24 to 36 hours of harvest. After removing from light, specimens 110 and 111 were heated in a circulating air convection oven, Sharp Carousel Convection / Microwave Model No. R-9H84B. Sample 110 was heated rapidly at about 148.9 ° C. (about 300 ° F.) for 5-10 minutes. Sample 111 was heated at about 33.8 ° C. (about 100 ° F.) and slowly heated to about 65.6 ° C. (about 150 ° F.) after 10 minutes, for a total of 20 minutes. The TSNA content of Samples 108-111 was measured using the procedure described in Example 1. The results are shown in Table 13 below.

Sample number NNN NAT & NAB NNK TSNA 108-controlled thin vein 1.267 2.509 1.377 5.153 109-Control Vein <0.004 0.464 <0.004 0.472 Rapid heating in 110-convection oven <0.004 <0.005 <0.004 <0.013 Slow heating in 111-convection oven <0.003 <0.004 <0.003 <0.010

Although heating by a convection oven has been shown to reduce the TSNA content, the quality of the tobacco was not as good as that obtained by microwave treatment in accordance with a preferred embodiment of the present invention. In addition, longer heating times were required than with microwave radiation or other forms of high frequency radiation. In particular, convective heating could not fix the color to the desired golden color, and the leaf veins tended to be overdried and fragile, while the leaf veins and veins were not completely dried. In contrast, according to the most preferred embodiment of the present invention, the leaves treated with microwaves were effectively dried and golden after treatment, in particular flexible and well bent for further processing into cigarettes. In specimens prepared in a convection oven, the leaf veins tended to crumble into powder and small tobacco particles when dried.

<Example 14>

Kentucky Burley cigarettes were harvested and processed as follows when they began to turn yellow about 24 to 48 hours after harvest. Samples 112-117 are leaf samples from this batch and were further processed as follows. Sample 112 was microwaved under approximately the same conditions as sample 106 in Example 12. The leaves are golden and effectively dried. Samples 113, 114, and 117 were heated in the same circulating air convection oven as described in Example 13. That is, sample 113 was heated under approximately the same conditions as sample 110, sample 114 was heated under approximately the same conditions as sample 111, and sample 117 was heated at about 176.7 ° C. (about 350 ° F.) for about 20 minutes. The quality of Samples 113, 114, and 117 was similar to the quality of Samples 110 and 111, described in Example 13. Samples 115 and 116 were heated in a Sharp carousel convection / microwave oven as described in Example 13 using combined microwave (30%) / convection (300 ° C.) characteristics until the leaves were effectively dried to golden color. . The TSNA content of Samples 112-117 was measured using the procedure described in Example 1. The results are shown in Table 14 below.

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

<Example 15>

Virginia flu tobacco was harvested and the leaves were placed in ripening light at about 33.8-43.3 ° C. (about 100-110 ° F.) to begin the flu ripening process. Specimens 118-120 are leaf specimens, which began to turn yellow and were removed from the light and immediately afterwards microwaved in a conventional home microwave oven for about 2 to 2½ minutes until the leaves did not burn or become black and effectively dried to golden color. . Samples 121-123 are Kentucky Burley Tobacco, harvested and processed after yellowing, respectively. Sample 121 was placed in a conventional steam tumble dryer at a temperature of about 93.3 ° C. (about 200 ° F.) typically used in the tobacco industry until the leaves became brown and somewhat dry. Sample 122 was microwaved in the high power Goldstar microwave oven mentioned above for about 2 minutes, rehydrated with water and placed in a tumble dryer to give the leaves some brownish color that is believed to be fortified. Sample 123 was treated as sample 122 except that it was microwaved for 1 minute and not rehydrated before being placed in a tumble dryer. TSNA content was measured similarly to Example 1 and the results are shown in Table 15 below.

Sample number 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>

The North Carolina Burley Tobacco was harvested and the leaves were processed after about 2-3 days after harvesting and the leaves began to turn yellow. Sample 118 is a leaf sample microwaved for 2 minutes in a Goldstar microwave oven of the same type described above set to high power. After microwave treatment the leaves were golden and effectively dried. TSNA content was measured using the procedure described in Example 1. The results are shown in Table 16 below.

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

<Example 17>

This example demonstrates the usefulness of using electron beam radiation to dampen the content of TSNA in yellow tobacco samples or substantially prevent the formation of TSNA. Harvested North Carolina Burley Tobacco. Specimens 119-122 are air-aged leaf specimens by hanging them externally in a conventional manner until the leaves are effectively dried and turned brown. Sample 119 is an untreated control. Samples 120 and 121 were treated with electron beam radiation on a conveyor belt at a exposure rate of 1 megarad using a Dynamitron electron beam accelerator from Radiation Dynamics, Inc., Edgewood, NY. Sample 122 was microwaved for about 2 minutes in a Goldstar microwave oven set to high power. Sample 123 was taken from the end of the bergley leaf after it began to turn yellow. Sample 124 was the leaf stem portion obtained from the same plant as sample 123 and was still somewhat green. Samples 125 and 126 are complete leaf burley specimens that are in the yellowing stage. Each of specimens 123-126 was subjected to electron beam radiation using the dynamtron mentioned above in the same manner under the same exposure rates as specimens 120 and 121, as described above. The specimens were examined to determine TSNA content according to the procedure described in Example 1, and the results are shown in Table 17 below.

Sample number NNN NAT & NAB NNK TSNA 119-Control, matured 3.6351 1.0847 0.0470 4.7668 120-high power, aged 6.5718 3.7037 0.4368 10.7123 121-Low Power, Aged 4.4771 1.6112 0.7468 6.8369 122-microwave, matured 4.8974 1.6393 1.1200 7.6567 123-yellow tip 0.1812 0.3667 0.0013 0.5492 124-green stem 0.1918 0.8310 0.0016 1.0243 125-complete leaf 0.0014 0.1019 0.0016 0.1048 126-complete leaf 0.0646 0.2465 0.0019 0.3130

The data indicate that electron beam radiation is effective in preventing the formation of significant amounts of tobacco-specific nitrosamines in examined yellow leaf specimens, but as described in other examples of this application, The leaves did not dry as effectively as when the leaves were microwaved. Thus, commercial application of the electron beam irradiation process may require additional drying steps, such as conveying the irradiated leaves through a conventional drying oven to facilitate the ripening process.

Example 18

This embodiment demonstrates that the high energy beam generated by the laser is also effective in achieving the low TSNA target of the present invention. Yellow Virginia flu tobacco leaves were examined about 2-3 days after harvest using a CO ₂ laser from Luxar corp., Model LX-20SP. NovaScan handpieces were used under the SuperPulse E program to determine the rate of application of the pattern per second. A series of E10s was used, delivering 10 patterns per second. Eight subsamples of leaves, T-1-T-8, were examined according to the following protocol.

E10-2 W E10-4 W T-1-passes through each side once T-5-pass each side once T-2-passes through each side twice T-6-passes through each side twice T-3-passes through each side three times T-7-passes through each side 3 times T-4-passes through each side 4 times T-8-passes through each side four times

At 2 W, approximately 120 mJ of energy was delivered every scan or pass, and at 4 W, approximately 240 mJ was delivered every scan. Subsamples T-1 to T-4 were mixed and combined to form leaf specimen 127 to assess TSNA content in the same manner described in Example 1. Subsamples T-5 to T-8 were similarly mixed and combined to form leaf specimen 128 and TSNA content was similarly evaluated. The results are shown in Table 18 below.

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

As with the sample described in Example 17, the CO ₂ laser irradiated to the sample did not dry as effectively as the microwave treated sample, but the TSNA content was low, thus using additional drying steps to speed up the aging process. Could. In addition, after the CO ₂ laser irradiation before the TSNA test, 6 of the 8 subsamples turned somewhat brown and there was no obvious effect on the TSNA content.

Example 19

This example demonstrates that gamma radiation is also effective in preventing the formation of significant amounts of TSNA in yellow tobacco. Virginia flu tobacco was taken immediately after the leaves turned yellow after about 2-3 days of harvest. Each sample 129 to 132 was taken from the leaf vein portion of the yellow leaf and irradiated with 10 KGrey (1 mega rad) gamma at an exposure rate of 8 kGrey (0.8 mega rad) per hour in a closed chamber and the total exposure time was approximately 75 minutes. The examined samples were subsequently evaluated for TSNA content in the same fashion as described above and the results are shown in Table 19 below.

Sample number NNN NAT & NAB NNK 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 modifications and variations can be made in the preferred embodiments without departing from the spirit and scope of the claimed invention. Accordingly, the description is for illustrative purposes only and should not be regarded as limiting.

Claims (76)

(i) removing the stem from the tobacco leaf, (b) compressing the tobacco leaf to remove excess moisture, or (c) steaming the tobacco leaf, and (ii) sufficient to reduce or substantially prevent the formation of at least one nitrosamine in an unmatured portion that is at least in a state that reduces the amount of nitrosamines in the plant or is prone to preventing the formation of nitrosamines. Tobacco leaves or parts thereof, which are treated with microwave radiation for a period of time, which are arranged in a single layer of thickness without clumping or stacking of leaves after the leaves begin to turn yellow and before the tobacco-specific nitrosamine accumulates significantly. Steps to do for To reduce the amount of nitrosamines in the harvested tobacco plants or to prevent the formation of nitrosamines. The method of claim 1, wherein step (i) is (b) or (c) and the tobacco leaf has a stem. Treating the unmatured yellow portion of the plant in at least a condition prone to preventing the formation of nitrosamines with aggregated radiation higher in frequency than the microwave region of the electromagnetic spectrum for a time sufficient to substantially prevent the formation of one or more nitrosamines. And substantially preventing the formation of nitrosamines in the harvested tobacco plants. 4. The method according to claim 3, wherein said radiation treatment is carried out on tobacco leaves or parts thereof, before the tobacco-specific nitrosamine accumulates significantly on the leaves or parts thereof. 4. A method according to claim 3, wherein said radiation treatment is carried out before the cell integrity of the plant is considerably lost. The method of claim 3, wherein the tobacco is flu tobacco and the radiation treatment is performed within about 24 to about 72 hours after harvest. The method of claim 3, wherein the radiation is applied to the plant for at least about 1 second at a predetermined power level. 4. The method of claim 3, wherein said radiation treatment prevents the normal accumulation of one or more tobacco-specific nitrosamines on the leaves. The nitrosamine peculiar to at least one tobacco is N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N The method is selected from '-nitrosoanathabin and N'-nitrosoanabasin. 5. The method of claim 4, wherein said radiation treatment is performed on tobacco leaves arranged in a single ply thickness without clumping or stacking of leaves. The method of claim 10, further comprising (a) removing the stem from the tobacco leaf, compressing the tobacco leaf to remove excess moisture, or (c) steaming the tobacco leaf before the radiation treatment. How to. The method of claim 3 comprising drying a portion of the plant after performing a radiation treatment step. 4. The method of claim 3, wherein said radiation is generated by a laser beam. 4. The method of claim 3, wherein the radiation is an electron beam generated by an electron accelerator. The method of claim 3, wherein the radiation is gamma rays. Prepared by a method comprising the step of treating an unmatured yellow tobacco in a state susceptible to formation of at least one tobacco-specific nitrosamine with aggregated radiation having a frequency higher than that in the microwave region of the electromagnetic spectrum, 1 A tobacco product comprising a tobacco having a reduced content of nitrosamines characteristic of at least one tobacco. 17. The tobacco product of claim 16, wherein the radiation treatment is performed before significant accumulation of tobacco-specific nitrosamines on the leaves. 17. The tobacco product of claim 16, wherein the radiation treatment is performed before the cellular integrity of the tobacco is significantly lost. 18. The tobacco product of claim 17, wherein the tobacco is flu tobacco, and the radiation treatment is performed within about 24 to about 72 hours after harvest. The tobacco product of claim 16, wherein the radiation is applied to the plant for at least about 1 second at a predetermined power level. 21. The tobacco product of claim 20, wherein said radiation treatment prevents the normal accumulation of one or more tobacco-specific nitrosamines on the leaves. 22. The method of claim 21, wherein the at least one tobacco specific nitrosamine is N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N A tobacco product selected from '-nitrosoanatabin and N'-nitrosoanabasin. 18. The tobacco product of claim 17, wherein the radiation treatment is performed on tobacco leaves arranged in a single ply thickness without clumping or stacking of leaves. 24. The method of claim 23, further comprising: (a) removing the stem from the tobacco leaf prior to the radiation treatment, (b) compressing the tobacco leaf to remove excess moisture, or (c) steaming the tobacco leaf. Tobacco products produced by the method. 17. The tobacco product of claim 16, further comprising the step of drying a portion of the plant after performing a radiation treatment step. 17. The tobacco product of claim 16, wherein said radiation is generated by a laser beam. 17. The tobacco product of claim 16, wherein said radiation is an electron beam generated by an electron accelerator. 17. The tobacco product of claim 16, wherein said radiation is gamma ray. delete delete delete Reduce the amount of tobacco-specific nitrosamines or reduce the amount of one or more tobacco-specific nitrosamines in the leaves of unmature tobacco leaves that are in a condition that is susceptible to the formation of tobacco-specific nitrosamines. Treating with coherent radiation having a higher frequency than the microwave region of the electromagnetic spectrum for a time sufficient to substantially prevent formation, and Molding a tobacco product comprising the irradiated leaves Tobacco comprising, cigarettes, cigars, chewing tobacco, snuff, and tobacco-containing gums and lozenges. 33. The method of claim 32, wherein the leaves are treated with radiation after the leaves begin to turn yellow and before the tobacco-specific nitrosamine accumulates significantly. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete