WO2013142483A1 - Method for treating an extracted tobacco pulp and tobacco products made therefrom - Google Patents

Abstract

The invention provides a method of producing a tobacco composition for use in a tobacco product, the method including treating a tobacco pulp with supercritical carbon dioxide. The treated tobacco pulp may exhibit a benzo[a]pyrene concentration lower than the initial benzo[a]pyrene concentration and/or a TSNA concentration lower than the initial TSNA concentration. The treated pulp can be introduced into tobacco products including smoking articles, smokeless tobacco products, and aerosol-generating devices configured for non-combustion of plant materials.

Description

METHOD FOR TREATING AN EXTRACTED TOBACCO PULP AND TOBACCO

PRODUCTS MADE THEREFROM

FIELD OF THE DISCLOSURE

The present disclosure relates to products made or derived from tobacco, or that otherwise incorporate tobacco, and are intended for human consumption. In particular, the disclosure relates to compositions or formulations incorporating tobacco, such as those intended to be employed in a smokeless form.

BACKGROUND OF THE INVENTION

Cigarettes, cigars, and pipes are popular smoking articles that employ tobacco in various forms. Such smoking articles are employed by heating or burning tobacco to generate aerosol (e.g., smoke) that may be inhaled by the smoker. Tobacco may also be enjoyed in a so-called

"smokeless" form. Particularly popular smokeless tobacco products are employed by inserting some form of processed tobacco or tobacco-containing formulation into the mouth of the user. See for example, the types of smokeless tobacco formulations, ingredients, and processing

methodologies set forth in US Pat. Nos. 1,376,586 to Schwartz; 3,696,917 to Levi; 4,513,756 to Pittman et al; 4,528,993 to Sensabaugh, Jr. et al; 4,624,269 to Story et al.; 4,991,599 to Tibbetts; 4,987,907 to Townsend; 5,092,352 to Sprinkle, III et al.; 5,387,416 to White et al.; 6,668,839 to Williams; 6,834,654 to Williams; 6,953,040 to Atchley et al.; 7,032,601 to Atchley et al.; and 7,694,686 to Breslin et al.; US Pat. Pub. Nos. 2004/0020503 to Williams; 2005/0115580 to Quinter et al.; 2005/0244521 to Strickland et al; 2006/0191548 to Strickland et al.; 2007/0062549 to Holton, Jr. et al.; 2007/0186941 to Holton, Jr. et al.; 2007/0186942 to Strickland et al.;

2008/0029110 to Dube et al.; 2008/0029116 to Robinson et al.; 2008/0029117 to Mua et al;

2008/0173317 to Robinson et al.; 2008/0196730 to Engstrom et al.; 2008/0209586 to Neilsen et al.; 2008/0305216 to Crawford et al.; 2009/0065013 to Essen et al; and 2009/0293889 to Kumar et al.; PCT WO 04/095959 to Arnarp et al.; and US Pat. Appl. Serial No. 12/638,394, filed December 15, 2009, to Mua et al.; each of which is incorporated herein by reference.

One type of smokeless tobacco product is referred to as "snuff." Representative types of moist snuff products, commonly referred to as "snus," are manufactured in the United States and Europe, particularly in Sweden. See, for example, Bryzgalov et al, 1N1800 Life Cycle

Assessment, Comparative Life Cycle Assessment of General Loose and Portion Snus (2005). In addition, certain quality standards associated with snus manufacture have been assembled as a so- called GothiaTek standard. Exemplary smokeless tobacco products include CAMEL Snus, CAMEL Orbs, CAMEL Strips and CAMEL Sticks by R. J. Reynolds Tobacco Company; REVEL Mint Tobacco Packs and SKOAL Snus by U.S. Smokeless Tobacco Company; and MARLBORO Snus and Taboka by Philip Morris USA.

Various treatment methods and additives have been proposed for altering the overall character or nature of tobacco materials utilized in tobacco products. For example, additives or treatment processes have been utilized in order to alter the chemistry or sensory properties of the tobacco material, or in the case of smokable tobacco materials, to alter the chemistry or sensory properties of mainstream smoke generated by smoking articles including the tobacco material. See, for example, Leffingwell et al., Tobacco Flavoring for Smoking Products, R.J. Reynolds Tobacco Company (1972), which is incorporated herein by reference. In addition, tobacco materials have been processed or blended in a manner designed to achieve certain sensory or chemistry characteristics. See, for example, US Pat. No. 7,025,066 to Lawson et al. and US Pat. Pub. No. 2008/0245377 to Marshall et al., which are incorporated herein by reference.

It would be desirable to provide an enjoyable form of tobacco product, such as a smokeless tobacco product, and to provide processes for preparing tobacco-containing compositions suitable for use in smokeless tobacco products.

SUMMARY OF THE INVENTION

The present invention relates to a tobacco product, such as a smokeless tobacco product (e.g., moist snuff, dry snuff, chewing tobacco, tobacco-containing gums, and dissolvable or meltable tobacco products) intended or configured for insertion into the mouth of a user, and to processes for preparing a formulation suitable for use within such a tobacco product. The tobacco products of the invention include a flavorful tobacco composition such as one having the form of a fire-cured tobacco extract. In one embodiment, the invention provides fire-cured tobacco extracts that exhibit distinctive sensory characteristics associated with fire-cured tobacco (e.g., smoky aroma or flavor), while also exhibiting advantageous chemical composition differences as compared to fire-cured tobacco in whole form, such as reduced levels of benzo[a]pyrene or other polycyclic aromatic hydrocarbons.

The extract is typically an aqueous extract of the cured tobacco material, but certain other polar protic solvents or co-solvent mixtures that include water can be used without departing from the invention. The concentration of benzo[a]pyrene in the extract is typically no more than about 10 ppb and often no more than about 5 ppb.

Although smokeless tobacco composition are particularly important types of tobacco products that would benefit from the extracts of the invention, other tobacco products can also benefit from such flavorful tobacco compositions, such as smoking articles (e.g., cigarettes) or aerosol-generating devices that contain tobacco or tobacco components but which do not combust tobacco or other plant material. Typically, the tobacco product will comprise a tobacco material or a non-tobacco plant material as a carrier for the extract.

In another embodiment, the extract of the invention is used to form a reconstituted tobacco material. In particular, such a material can include the extract of the invention (e.g., a fire-cured tobacco extract) combined with an extracted tobacco pulp (e.g., a fire-cured tobacco pulp), wherein the pulp has been pre-treated to reduce benzo[a]pyrene concentration. For example, the fire-cured tobacco extracted pulp can be pre-treated by supercritical carbon dioxide extraction to reduce benzo[a]pyrene concentration.

In another aspect, the invention provides a method of producing a flavorful tobacco composition characterized by sensory attributes associated with a fire-cured tobacco material and a reduced benzo[a]pyrene concentration. The method includes the step of mixing a fire-cured tobacco material having a first benzo[a]pyrene concentration (e.g., at least about 100 ppb benzo[a]pyrene) with a polar protic solvent (e.g., water or co-solvent mixtures including water) to produce a slurry, the slurry providing intimate contact between the fire-cured tobacco material and the polar protic solvent. The method also includes maintaining the slurry for a time and at a temperature sufficient to form an extract comprising components of the cured tobacco material soluble in the polar protic solvent, the extract exhibiting a second benzo[a]pyrene concentration (e.g., less than about 10 ppb benzo[a]pyrene) lower than the first benzo[a]pyrene concentration.

Thereafter, the extract is separated from a residual pulp material comprising components of the fire- cured tobacco material that are insoluble in the polar protic solvent. The method typically also includes the step of utilizing the extract as a flavorful tobacco composition by, for example, introducing the separated extract into a tobacco product, which will often involve applying the separated extract to a tobacco material or non-tobacco plant material to form a treated material that can then be incorporated into a tobacco product. In certain embodiments, the extract is recombined with the extracted pulp following treatment of the pulp to reduce benzo[a]pyrene content, such as a second extraction of the pulp adapted to remove benzo[a]pyrene. For example, the method can include treating the residual pulp material with supercritical carbon dioxide to reduce

benzo[a]pyrene concentration and form a pulp material with reduced benzo[a]pyrene concentration, and thereafter applying the separated extract to the pulp material with reduced benzo[a]pyrene concentration to form the treated material. If desired, the extract can be concentrated by removing at least a portion of the solvent prior to incorporation into a tobacco product. In one particular embodiment, the invention provides a process for preparing a composition suitable for use as a smokeless tobacco composition, comprising: mixing a fire-cured tobacco material having a first benzo[a]pyrene concentration with water to produce an aqueous slurry, the slurry providing intimate contact between the fire-cured tobacco material and the water;

maintaining the slurry for a time and at a temperature sufficient to form a fire-cured tobacco extract comprising flavorful and aromatic components of the fire-cured tobacco material soluble in water, the aqueous fire-cured tobacco extract exhibiting a second benzo[a]pyrene concentration lower than the first benzo[a]pyrene concentration; separating the aqueous fire-cured tobacco extract from a residual pulp material comprising components of the fire-cured tobacco material that are insoluble in water; and mixing the aqueous fire-cured tobacco extract with a tobacco or non-tobacco plant material to form a smokeless tobacco composition.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to provide an understanding of embodiments of the invention, reference is made to the appended drawings, which are not necessarily drawn to scale, and in which reference numerals refer to components of exemplary embodiments of the invention. The drawings are exemplary only, and should not be construed as limiting the invention.

FIG. 1 is an exploded perspective view of a smoking article having the form of a cigarette, showing the smokable material, the wrapping material components, and the filter element of the cigarette; and

FIG. 2 is a cross-sectional view of a smokeless tobacco product embodiment, taken across the width of the product, showing an outer pouch filled with a smokeless tobacco composition of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention now will be described more fully hereinafter. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. As used in this specification and the claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Reference to "dry weight percent" or "dry weight basis" refers to weight on the basis of dry ingredients (i.e., all ingredients except water).

The present invention provides a process for preparing a flavorful tobacco composition it the form of a tobacco extract. In certain embodiments, the extracts of the invention provide a tobacco composition having advantageous sensory characteristics combined with a reduced amount of certain compounds found in the unextracted tobacco material. The process of the invention is particularly useful for forming an extract of a fire-cured tobacco material, although it can be applied to other tobacco materials such as tobacco cured using other curing techniques (e.g., air- cured and/or flue-cured tobacco materials). See, for example, techniques for curing tobacco set forth in US Pat. App. Pub. No. 2012/0037175 to Cantrell et al. and selected references cited therein, which are incorporated by reference in their entireties.

A "fire-cured tobacco" as used herein refers to a tobacco material subjected to a fire curing process. In fire curing, tobacco leaves are exposed to gaseous combustion products from an open fire in the curing enclosure, typically for several weeks, resulting in a distinctive smoky aroma and flavor. The distinctive sensory characteristics of fire-cured tobacco can also be described in some cases as woody, sweet, nutty, spicy, earthy, or sour. The fire used for such curing processes is typically characterized as low-burning or smoldering, meaning the fire is maintained in a state that promotes smoke production. Fire cured tobaccos are sometimes referred to as "dark fire" or "dark- fired" tobacco. See, for example, the fire-curing processes and resulting tobacco characteristics set forth in US Pat. Nos. 7,650,891 and 7,650,892, both to Groves et al., and 7,757,697 to Thomas et al., all of which are incorporated by reference herein. See also, pages 164-182 of Tobacco

Production, Chemistry and Technology, Davis et al. (Eds.) (1999).

During fire curing, the tobacco material is involved in intimate interaction and contact with the gaseous combustion products of the fire in the curing enclosure, meaning the smoke from the fire directly contacts the surface of the tobacco material. This interaction between the smoke and the tobacco results in chemical changes to the tobacco material that lead to both the distinctive smoky aroma and flavor commonly associated with fire-cured tobacco and other less desirable chemical changes in the tobacco. The present invention provides a treatment process that separates at least a portion of the components of the fire-cured tobacco that provide the distinctive sensory characteristics (i.e., smoky aroma and flavor) from at least a portion of the components of the fire- cured tobacco that do not contribute to a significant degree to the desired and distinctive sensory characteristics. In other words, the invention provides a separation process that selectively extracts components of fire-cured tobacco that are desirable from a sensory standpoint, but leaves behind at least a portion of those components that are not necessary or desirable from a sensory standpoint.

When the process of the invention is applied to a fire-cured tobacco material, an extract can be formed in certain embodiments that is characterized by the desirable sensory attributes (e.g., smoky aroma and flavor) associated with fire-cured tobacco, but with an altered chemistry profile that includes reduction in certain polycyclic aromatic hydrocarbons typically found in fire-cured tobacco, such as benzo[a]pyrene (i.e., of BaP is given below.

Benzo[a]pyrene

Discussion of BaP and other polycyclic aromatic hydrocarbons can be found in Gelboin,

Physiological Reviews 60(4) (1980) 1107-1166; Phillips, Mutation Research 443 (1999) 139-147; Rodgman and Perfetti, Contributions to Tobacco Research 22(1) (2006) 13-69; Rodgman and Cook, Contributions to Tobacco Research 23(6) (2009) 384-410; and A. Rodgman and T. A. Perfetti, The Chemical Components of Tobacco and Tobacco Smoke, CRC Press, Taylor and Francis Group, Boca Raton, USA, (2009), all of which are incorporated by reference herein.

Fire-cured tobacco extracts containing reduced levels of polycyclic aromatic hydrocarbons enable the production of smoking articles and smokeless tobacco compositions that exhibit the desirable sensory characteristics of fire-cured tobacco, but with reduced content of compounds not associated with the desirable sensory properties, such as BaP. It is noted that sensory

characteristics of a composition can be evaluated using human sensory panels as is understood in the art.

Although the BaP content can vary based on the particular tobacco plant and specific fire- curing process employed, a typical BaP range for a fire-cured tobacco is about 150 to about 800 parts by billion (ppb). In certain embodiments of the invention, fire-cured tobacco extracts can be formed with significantly lower BaP levels, such as less than about 10 ppb, less than about 5 ppb, or even less than about 1 ppb. In other terms, the amount of BaP reduction that occurs during the extraction process of the invention can be characterized as a reduction of at least about 90 percent by weight of the content of BaP in the original unextracted tobacco material, more often at least about 95 percent or at least about 99 percent. It was heretofore unknown that a fire-cured tobacco extract could be formed that retains the distinctive sensory elements of such tobaccos, but which exhibits a reduced content of certain less desirable chemical compounds such as BaP. In one embodiment of the method of the invention, the cured tobacco material (e.g., fire-cured tobacco) subjected to the extraction process has a BaP concentration of at least about 100 ppb, more often at least about 150 ppb, or even at least about 200 ppb or at least about 300 ppb. Following the extraction process, the separated extract exhibits a much lower BaP concentration, such as a concentration of no more than about 10 ppb, or no more than about 5 ppb, or no more than about 1 ppb.

Various methods for determining BaP content are known in the art. Typically, the method involves extracting BaP from a tobacco material with methanol or a relatively non-polar solvent such as hexane, cyclohexane or methylene chloride. The extract is then filtered and analyzed using a High Performance Liquid Chromatography (HPLC) method with fluorescence detection or a Gas Chromatography-Mass Spectrometry (GC-MS) technique. Publications directed to extraction and detection of BaP in tobacco or tobacco products include Rodgman and Perfetti, Contributions to Tobacco Research 22(1) (2006) 13-69; Risner, Beitr, Tabakforsch. Int. 15(1) (1991) 11-17;

"Determination of Benzo [a]Pyrene in Whole Tobacco," Health Canada (1999) (published on the Health Canada website, www.hc-sc.gc.ca). Aygiin et al., International Journal of Food Sciences and Nutrition 56(8) (2005) 581-585; and McNeill et al., Tob. Control 15 (2006) 64-67, all of which are incorporated by reference herein.

The fire-cured tobacco used in the process of the invention can include those tobacco materials commonly utilized in fire curing, such as Narrow Leaf Madole, Improved Madole, Tom Rosson Madole, Newton's VH Madole, Little Crittenden, Green Wood, Little Wood, Small Stalk Black Mammoth, DT 508, DT 518, DT 592, KY 171, DF 911, DF 485, TN D94, TN D950, VA 309, and VA 359. However, any tobacco material could be used without departing from the invention, including those tobaccos commonly referred to as flue-cured or Virginia (e.g., K326), burley, sun-cured (e.g., Indian Kurnool and Oriental tobaccos, including Katerini, Prelip, Komotini, Xanthi and Yambol tobaccos), Maryland, dark, dark air cured (e.g., Passanda, Cubano, Jatin and Bezuki tobaccos), light air cured (e.g., North Wisconsin and Galpao tobaccos), Indian air cured, Red Russian and Rustica tobaccos, as well as various other rare or specialty tobaccos. Descriptions of various types of tobaccos, growing practices and harvesting practices are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999), which is incorporated herein by reference. Various representative types of plants from the Nicotiana species are set forth in Goodspeed, The Genus Nicotiana, (Chonica Botanica) (1954); US Pat. Nos. 4,660,577 to

Sensabaugh, Jr. et al.; 5,387,416 to White et al. and 7,025,066 to Lawson et al.; US Patent Appl. Pub. Nos. 2006/0037623 to Lawrence, Jr. and 2008/0245377 to Marshall et al.; each of which is incorporated herein by reference. In one embodiment, tobacco varieties that are typically cured through curing processes other than fire curing, such as flue-curing or air-curing, are utilized in the extraction process of the invention. If desired, such tobacco materials can be optionally cured using a fire curing treatment instead of the traditional curing process used for such materials. The particular Nicotiana species of material used in the invention could also vary. Of particular interest are N. alata, N. arentsii, N. excelsior, N. forgetiana, N. glauca, N. glutinosa, N. gossei, N. kawakamii, N. knightiana, N. langsdorffi, N. otophora, N. setchelli, N. sylvestris, N. tomentosa, N. tomentosiformis, N. undulata, and N. x sanderae. Also of interest are N. africana, N. amplexicaulis, N. benavidesii, N. bonariensis, N. debneyi, N. longiflora, N. maritina, N.

megalosiphon, N. occidentalis, N. paniculata, N. plumbaginifolia, N. raimondii, N. rosulata, N. rustica, N. simulans, N. stocktonii, N. suaveolens, N. tabacum, N. umbratica, N. velutina, and N. wigandioides. Other plants from the Nicotiana species include N. acaulis, N. acuminata, N.

attenuata, N. benthamiana, N. cavicola, N. clevelandii, N. cordifolia, N. corymbosa, N. fragrans, N. goodspeedii, N. linearis, N. miersii, N. nudicaulis, N. obtusifolia, N. occidentalis subsp. Hersperis, N. pauciflora, N. petunioides, N. quadrivalvis, N. repanda, N. rotundifolia, N. solanifolia and N. spegazzinii. The Nicotiana species can be derived using genetic-modification or crossbreeding techniques (e.g., tobacco plants can be genetically engineered or crossbred to increase or decrease production of certain components or to otherwise change certain characteristics or attributes). See, for example, the types of genetic modifications of plants set forth in US Pat. Nos. 5,539,093 to Fitzmaurice et al.; 5,668,295 to Wahab et al; 5,705,624 to Fitzmaurice et al.; 5,844,119 to Weigl; 6,730,832 to Dominguez et al.; 7,173,170 to Liu et al.; 7,208,659 to Colliver et al.; and 7,230,160 to Benning et al.; US Patent Appl. Pub. No. 2006/0236434 to Conkling et al.; and PCT WO 2008/103935 to Nielsen et al.

At least a portion of the plant of the Nicotiana species can be employed in an immature form (i.e., the plant, or at least one portion of that plant, can be harvested before reaching a stage normally regarded as ripe or mature, such as, for example, when the tobacco plant is at the point of a sprout, is commencing leaf formation, is commencing flowering, or the like). At least a portion of the plant can be employed in a mature form (i.e., the plant, or at least one portion of the plant can be harvested when that plant (or plant portion) reaches a point that is traditionally viewed as being ripe, over-ripe, or mature). As such, for example, through the use of tobacco harvesting techniques conventionally employed by farmers, Oriental tobacco plants can be harvested, burley tobacco plants can be harvested, or Virginia tobacco leaves can be harvested or primed by stalk position. The tobacco material used in the invention can also be subjected to aging conditions.

The plant can, in certain embodiments, be used in a green form (e.g., tobacco can be used without being subjected to any curing process). For example, tobacco in green form can be frozen, subjected to irradiation, yellowed, dried, cooked (e.g., roasted, fried or boiled), or otherwise subjected to storage or treatment for later use. Such tobaccos can also can be subjected to aging conditions. According to the invention, a tobacco material of any of the types noted above is harvested and subjected to a curing process, such as a fire curing process. The resulting cured tobacco is then subjected to an extraction process using certain polar protic solvents, such as water, formic acid, acetic acid, dilute aqueous solutions (e.g., solutions comprising greater than 70 weight percent water and minor amounts of an alcohol or other co-solvent), or mixtures thereof. The solvent typically has a dielectric constant at room temperature of at least about 6, more often at least about 30, and most often at least about 50.

Solvents having an aqueous character are particularly useful, such as deionized water, distilled water, or tap water. Such a solvent consists primarily of water, is normally greater than 90 weight percent water, and can be essentially pure water in certain circumstances. The extraction solvent can be a co-solvent mixture, such as a mixture of water and minor amounts of one or more solvents that are miscible therewith. An example of such a co-solvent mixture is a solvent consisting of about 95 weight parts water and about 5 weight parts ethanol. The extraction solvent also can include water having substances such as pH adjusters (i.e., acids or bases) or pH buffers dissolved therein.

The extraction process involves placing the tobacco material in intimate contact with the solvent at a suitable temperature and for a suitable time period. The temperature of the extraction can vary, but a typical temperature range is about room temperature to about 1 10°C, more often about 30°C to about 90°C. In certain embodiments, the temperature of the extraction step can be characterized as at least about 20°C, at least about 30°C, at least about 50°C, or at least about 60°C. It may be advisable to use a relatively low temperature for the extraction process to prevent or reduce volatilization of the flavorful or aromatic compounds that are the primary targets of the extraction process.

The time period for the extraction step can vary, but is typically about 10 minutes to about 24 hours, more often about 1 hour to about 12 hours. The time period is not considered particularly critical to the invention, although very short extraction time periods may not result in extraction of a large proportion of the extractable component of the tobacco material.

The amount of solvent used in the extraction process can vary, but will typically be sufficient to place the tobacco material in the form of a slurry. In other words, the solvent is typically the predominate component of the tobacco/solvent mixture and is often present in great excess compared to the tobacco component. Weight ratios of solvent to tobacco material will typically range from about 2:1 to about 20:1 (e.g., about 4:1 to about 12:1), although other ratios (particularly even larger ratios) could be used without departing from the invention. In certain embodiments, the use of smaller amounts of water or other solvent could be advantageous because less drying would be required if the extract must be concentrated prior to use. Excessive drying of the extract could lead to loss of certain volatile flavorful or aromatic components of the extract, which could potentially result in loss of some of the distinctive sensory characteristics of the extract. Accordingly, use of weight ratios of solvent to tobacco material of less than about 5: 1 or less than about 4:1 during extraction could be a useful technique to reduce or eliminate the need to dry or otherwise concentrate the resulting extract. In such an embodiment, the extract would be expected to exhibit a relatively high viscosity and can be applied to certain tobacco products without further processing.

The manner by which the solvent and the tobacco material are combined for extraction may vary. The solvent and tobacco material can be contacted, combined, or mixed together in conical- type blenders, mixing drums, ribbon blenders, or the like. The mixture can be agitated or subjected to a grinding action during the extraction step. Following extraction, the residual pulp is removed from the liquid extraction product using any method known in the art, such as filtration or centrifugation. The tobacco material is typically in shredded or particulate form during extraction, such as tobacco particles having a particle size in the range of about 0.5 mm to about 25 mm. The vessel in which the tobacco material and the solvent are mixed is typically vented such that the extraction proceeds at atmospheric pressure, or if desired, a pressurized vessel can be used.

Following the extraction process, a tobacco extract is provided by separating the solvent-insoluble pulp material from the solvent and the solvent-soluble or dispersible tobacco components dissolved or dispersed therein.

Equipment, types of solvents, and techniques for obtaining extracts of tobacco, including in some cases equipment, solvents, and techniques that can be used or suitably modified for use in the method of the invention, are described in US Pat. Nos. 4,144,895 to Fiore; 4,150,677 to Osborne, Jr. et al.; 4,267,847 to Reid; 4,289,147 to Wildman et al.; 4,351,346 to Brummer et al.; 4,359,059 to Brummer et al.; 4,506,682 to Muller; 4,589,428 to Keritsis; 4,605,016 to Soga et al.; 4,716,911 to Poulose et al.; 4,727,889 to Niven, Jr. et al.; 4,887,618 to Bernasek et al.; 4,941,484 to Clapp et al; 4,967,771 to Fagg et al; 4,986,286 to Roberts et al.; 5,005,593 to Fagg et al.; 5,018,540 to Grubbs et al.; 5,060,669 to White et al.; 5,065,775 to Fagg; 5,074,319 to White et al.; 5,099,862 to White et al.; 5,121,757 to White et al; 5,131,414 to Fagg; 5,131,415 to Munoz et al.; 5,148,819 to Fagg; 5,197,494 to Kramer; 5,230,354 to Smith et al.; 5,234,008 to Fagg; 5,243,999 to Smith; 5,301,694 to Raymond et al.; 5,318,050 to Gonzalez-Parra et al.; 5,343,879 to Teague; 5,360,022 to Newton; 5,435,325 to Clapp et al; 5,445,169 to Brinkley et al.; 6,131,584 to Lauterbach; 6,298,859 to Kierulff et al.; 6,772,767 to Mua et al.; and 7,337,782 to Thompson, all of which are incorporated by reference herein. Following separation of the extract from the pulp, both the extract and the residual pulp can be further processed if desired. For example, the extract can be processed in a manner adapted to concentrate the dissolved or dispersed components of the tobacco material by removing at least a portion of the solvent. Various methods of solvent removal can be used, such as heat treatment to evaporate the solvent (e.g., with an evaporator and condenser arrangement), reverse osmosis membrane treatment, spray drying or freeze drying. In the case of an aqueous extract, the concentration step could simply entail heating the extract to a temperature above the boiling point of water in a vented vessel. The extract could also be subjected to other treatment processes designed to change the chemical composition of the extract, such as reaction with acids or bases, ultrafiltration to remove high molecular weight components, treatment to remove additional components of the extract such as tobacco-specific nitrosamines (TSNAs), or the like.

In one specific embodiment, the essentially BaP-free extract is processed to reduce the concentration of TSNAs in the extract. Exemplary TSNA compounds include N-nitrosonornicotine (NNN), 4-methyl-N-nitrosamino-l-(3-pyridyl)-l-butanone (NNK), N-nitrosoanatabine (NAT), 4- methyl-N-nitrosamino- 1 -(3 -pyridyl)- 1 -butanol (NNAL), and N-nitrosoanabasine (NAB) . The method for reducing the TSNA level can vary. In one method, a preparative HPLC technique is used where the extract is passed through a HPLC column and the portion of the extract eluting from the column at the known retention time for TSNA compounds is simply discarded. In another method, the extract is passed through a molecularly imprinted polymer (MIP) material having functional groups that selectively sorb TSNA compounds. Exemplary TSNA-specific MIP materials include polymer sorbents offered by Sigma-Aldrich Company under the brand name SupelMIP® SPE and Affinilute™ MIP materials available from Biotage AB. The polymeric sorbent can be contacted with the extract to selectively sorb the TSNA compounds using a variety of techniques such as packing a column with the sorbent and passing the extract therethrough. In certain embodiments, the TSNA level of the extract can be reduced from greater than 1,000 ppb or even greater than 2,000 ppb to less than about 400 ppb or less than about 300 ppb or less than about 200 ppb. In some cases, the TSNA level can be reduced to less than about 100 ppb or less than about 50 ppb.

In one embodiment, the residual tobacco pulp produced in the extraction process can be treated to reduce benzo[a]pyrene concentration in order to prepare the pulp for recombination with the extract to form a reconstituted tobacco material exhibiting a reduced benzo[a]pyrene concentration. For example, the pulp could be subjected to a second extraction process using supercritical carbon dioxide or another suitable solvent (e.g., relatively non-polar solvents such as hexane, cyclohexane or methylene chloride) such that the benzo[a]pyrene dissolves in the solvent to facilitate removal from the pulp. Carbon dioxide extraction processes that could be used in the present invention, or suitably modified for use in the present invention, are set forth in, for example, US Pat. Nos. 4,153,063 to Roselius et al.; 4,506,682 to Muller; 4,714,617 to Gahrs;

4,727,889 to Niven, Jr. et al.; 5,018,540 to Grubbs et al.; and 5,435,325 to Clapp et al., all of which are incorporated by reference herein.

In certain embodiments, the tobacco pulp is subjected to supercritical C0₂ extraction as further described herein. Generally, supercritical fluid extraction adds supercritical C0₂ to tobacco pulp to facilitate the removal of certain components (e.g., B[a]p and TSNA) from the tobacco pulp. The extraction can be conducted using any type of equipment capable of bringing the tobacco into contact with supercritical C0₂. For example, in some specific embodiments, a supercritical fluid extraction system, such as available from Jasco, Inc. (Easton, MD) can be used. In certain embodiments, pure supercritical C0₂ is the extraction medium; however, in certain embodiments, it may be possible to use an extraction medium that comprises one or more components in addition to supercritical C0₂. The extraction process may utilize a back flow medium (e.g., methanol) downstream to trap compounds that are extracted (i.e., removed) from the tobacco material.

Various parameters of the supercritical C0₂ extraction process can be varied. In certain embodiments, altering one or more of these parameters can alter the efficiency of the extraction process. For example, the pressure, temperature, C0₂ flow rate, and total extraction time can be varied. For example, in certain embodiments, a pressure of about 10 MPa or greater, and more preferably a pressure of about 20 MPa or greater is used. For example, in some embodiments, a pressure of between about 5 MPa and about 40 MPa (e.g., between about 10 MPa and about 40 MPa or between about 10 MPa and about 30 MPa) is used. In certain embodiments, a temperature of about 40 °C or greater is used, and more preferably, a temperature of about 60 °C or greater is used. For example, in some embodiments, a temperature of between about 30 °C and about 70 °C is used (e.g., between about 40 °C and about 60 °C). In certain embodiments, a flow rate of about 5 mL/min or greater is used, and more preferably, a flow rate of about 10 mL/min or greater is used. For example, in some embodiments, a flow rate of between about 4 mL/min and about 15 mL/min (e.g., between about 5 mL/min and about 10 mL/min) is used.

In certain embodiments, the total extraction time is about 10 minutes or more, about 15 minutes or more, or about 30 minutes or more. Typically, total extraction times of about 15 minutes or more result in good removal of both B[a]p and TSNA (e.g., greater than about 50% removal of both B[a]p and TSNA). In certain embodiments, total extraction times of about 30 minutes or more provided even greater removal of both B[a]p and TSNA. It is noted that, in some embodiments, higher or lower temperatures, higher or lower flow rates, and/or higher or lower total extraction times can be utilized to provide good results (i.e., a significant decrease in the concentration of B[a]p and/or TSNA).

In certain embodiments wherein the tobacco pulp treated by supercritical C0₂ extraction has been previously subjected to an aqueous extraction, the resulting treated pulp can be characterized as a "double-extracted" tobacco pulp. A double-extracted pulp thus comprises a pulp wherein aqueous components have been removed via aqueous extraction and additional components have been removed via supercritical C0₂ extraction.

The supercritical C0₂ extraction process generally results in a reduction in the amount of B[a]p and/or the amount of TSNA present in the tobacco material. In certain embodiments, the supercritical C0₂ extraction can provide a reduction in B[a]p of about 5% or more, about 10% or more, about 20% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 70% or more, or about 80% or more as compared with tobacco that has not been treated by supercritical C0₂ extraction. Generally, tobacco that has not been treated by

supercritical C0₂ extraction can have a B[a]p level that may be greater than about 50 ng/g, greater than about 100 ng/g, greater than about 150 ng/g, or greater than about 200 ng/g. In certain embodiments, tobacco pulp that has been treated by supercritical C0₂ extraction can be

characterized as having less than about 150 ng/g, less than about 100 ng/g, less than about 80 ng/g, or less than about 50 ng/g. In certain embodiments, the supercritical C0₂ extraction can provide a reduction in TSNA of about 5% or more, about 10% or more, about 20% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 70% or more, or about 80% or more as compared with tobacco that has not been treated by supercritical C0₂ extraction. Generally, tobacco that has not been treated by supercritical C0₂ extraction can have a TSNA level that may be greater than about 2,500 ng/g, greater than about 5,000 ng/g, greater than about 7,500 ng/g, or greater than about 10,000 ng/g. In certain embodiments, tobacco pulp that has been treated by supercritical C0₂ extraction can be characterized as having less than about 5,000 ng/g, less than about 7,500 ng/g, less than about 5,000 ng/g, less than about 2,000 ng/g, or less than about 1,000 ng/g.

Thereafter, a reconstituted tobacco material can be formed by adding the extract from the original extraction process back to the pre-treated pulp (e.g., the pulp that has been treated by supercritical carbon dioxide extraction). Exemplary manners and methods for providing a reconstituted tobacco sheet, including casting and paper-making techniques, are set forth in US Pat. Nos. 4,674,519 to Keritsis et al.; 4,941,484 to Clapp et al.; 4,987,906 to Young et al; 4,972,854 to Kiernan et al; 5,099,864 to Young et al.; 5,143,097 to Sohn et al.; 5,159,942 to Brinkley et al; 5,322,076 to Brinkley et al.; 5,339,838 to Young et al.; 5,377,698 to Litzinger et al.; 5,501,237 to Young; and 6,216,707 to Kumar; each of which is incorporated herein by reference. See also the tobacco extraction and reconstituted tobacco processes set forth in US Pat. Nos. 5,065,775 to Fagg and 5,360,022 to Newton et al., which are incorporated herein by reference.

The tobacco material that is subjected to the extraction process can also be subjected to pre- treatment processes adapted to modify the sensory, chemical or physical properties of the material. For example, it may be desirable to pre-treat the tobacco material to remove components of the tobacco that may generate negative sensory off-notes so that those components are not extracted in the process of the invention. Exemplary pre-treatment processes for the tobacco material include fermentation, bleaching, and the like.

In some embodiments of the invention, it is advantageous to pre-treat a fire-cured tobacco to change the sensory characteristics in a manner that can be characterized as generating a milder flavor or aroma. One exemplary process that can generate a milder flavor or aroma in certain tobacco materials, such as a fire-cured tobacco, is fermentation. During fermentation, bacteria interact with the tobacco material in a moist, temperature-controlled and pH-controlled

environment to alter the chemical profile of the tobacco material. Commercially available fermented tobacco materials could be used in the extraction process of the invention, such as moist snuff tobacco compositions marketed as GRIZZLY or KODIAK smokeless tobacco. Tobacco fermentation processes are described, for example, in Giacomo et al., Appl. Environ. Microbiol. 73(3) (2007) 825-837; US Pat. No. 5,372,149 to Roth et al.; and in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999), all of which are incorporated by reference herein.

The tobacco extract can be utilized as a flavorful tobacco composition that can be incorporated into a variety of tobacco products. In particular, fire-cured tobacco extracts of the invention can impart the distinctive sensory characteristics of fire-cured tobacco to various tobacco products without introducing significant amounts of certain chemical compounds associated with unextracted or whole fire-cured tobaccos, such as BaP. The tobacco extract (e.g., the aqueous tobacco extract) can be employed in a variety of forms. For example, the tobacco extract can be isolated in an essentially solvent free form, such as can be obtained as a result of the use of a spray drying or freeze drying process, or other similar types of processing steps. Alternatively, the aqueous tobacco extract can be employed in a liquid form, and as such, the content of tobacco solubles within the liquid solvent can be controlled by selection of the amount of solvent employed for extraction, concentration of the liquid tobacco extract by removal of solvent, addition of solvent to dilute the liquid tobacco extract, or the like.

The tobacco product to which the extracts of the invention are added can vary, and include any product configured or adapted to deliver tobacco or some component thereof to the user of the product. Exemplary tobacco products include smoking articles (e.g., cigarettes), smokeless tobacco products, and aerosol-generating devices that contain a tobacco material or other plant material that is not combusted during use.

Typically, the incorporation of the extract of the invention into a tobacco product will involve use of a tobacco material or non-tobacco plant material as a carrier for the extract, such as by absorbing the extract into the tobacco or other plant material or otherwise associating the extract with the carrier material, such as by adhesion of spray-dried particles of the extract on the carrier material. The types of tobacco that can serves as the carrier for the extracts of the invention can vary, and can include any of the tobacco types discussed herein, including various cured tobacco materials (e.g., flue-cured or air-cured tobaccos) or portions thereof (e.g., tobacco lamina or tobacco stems). In one embodiment, the tobacco to which the extract is applied is a fermented tobacco material, and the extract is applied either before, during, or after the fermentation process. The tobacco material to which the extract is applied will typically be characterized as having a relatively low BaP level, such as many air-cured or flue-cured tobacco materials or tobacco materials pre-treated to reduce BaP level. The physical configuration of the tobacco material to which the extract is added can also vary, and can include tobacco materials in shredded or particulate form, or in the form of a sheet (e.g., reconstituted tobacco sheets) or in whole leaf form. The dry weight ratio of tobacco material to extract of the invention can vary, but is typically about 4:1 to about 1:4, about 2:1 to about 1 :2, and often about 1.5:1 to about 1 :1.5.

In one embodiment, the extract of the invention is used as a flavorful tobacco composition in the manufacture of smoking articles. For example, the extract prepared in accordance with the present invention can be mixed with casing materials and applied to tobacco as a casing ingredient (e.g., using the types of methods set forth in US Pat. No. 4,819,668 to Shelar, which is incorporated herein by reference), incorporated into smoking articles as a top dressing ingredient, or

incorporated into reconstituted tobacco materials (e.g., using the types of tobacco reconstitution processes generally set forth in US Pat. Nos. 5,143,097 to Sohn; 5,159,942 to Brinkley et al.;

5,598,868 to Jakob; 5,715,844 to Young; 5,724,998 to Gellatly; and 6,216,706 to Kumar, which are incorporated herein by reference). Still further, the extracts of the invention can be incorporated into a cigarette filter (e.g., in the filter plug, plug wrap, or tipping paper) or incorporated into cigarette wrapping paper, preferably on the inside surface, during the cigarette manufacturing process.

Referring to FIG. 1, there is shown a smoking article 10 in the form of a cigarette and possessing certain representative components of a smoking article that can contain the extract of the present invention. The cigarette 10 includes a generally cylindrical rod 12 of a charge or roll of smokable filler material (e.g., about 0.3 to about 1.0 g of smokable filler material such as tobacco material) contained in a circumscribing wrapping material 16. The rod 12 is conventionally referred to as a "tobacco rod." The ends of the tobacco rod 12 are open to expose the smokable filler material. The cigarette 10 is shown as having one optional band 22 (e.g., a printed coating including a film-forming agent, such as starch, ethylcellulose, or sodium alginate) applied to the wrapping material 16, and that band circumscribes the cigarette rod in a direction transverse to the longitudinal axis of the cigarette. The band 22 can be printed on the inner surface of the wrapping material (i.e., facing the smokable filler material), or less preferably, on the outer surface of the wrapping material.

At one end of the tobacco rod 12 is the lighting end 18, and at the mouth end 20 is positioned a filter element 26. The filter element 26 positioned adjacent one end of the tobacco rod 12 such that the filter element and tobacco rod are axially aligned in an end-to-end relationship, preferably abutting one another. Filter element 26 may have a generally cylindrical shape, and the diameter thereof may be essentially equal to the diameter of the tobacco rod. The ends of the filter element 26 permit the passage of air and smoke therethrough.

A ventilated or air diluted smoking article can be provided with an optional air dilution means, such as a series of perforations 30, each of which extend through the tipping material and plug wrap. The optional perforations 30 can be made by various techniques known to those of ordinary skill in the art, such as laser perforation techniques. Alternatively, so-called off-line air dilution techniques can be used (e.g., through the use of porous paper plug wrap and pre-perforated tipping paper).

The extracts of the invention can also be incorporated into aerosol-generating devices that contain tobacco material (or some portion or component thereof) that is not intended to be combusted during use. Exemplary references that describe smoking articles of a type that generate flavored vapor, visible aerosol, or a mixture of flavored vapor and visible aerosol, include US Pat, Nos. 3,258,015 to Ellis et al.; 3,356,094 to Ellis et al.; 3,516,417 to Moses; 4,347,855 to Lanzellotti et al.; 4,340,072 to Bolt et al.; 4,391,285 to Burnett et al.; 4,917,121 to Riehl et al.; 4,924,886 to Litzinger; and 5,060,676 to Hearn et al., all of which are incorporated by reference herein. Many of these types of smoking articles employ a combustible fuel source that is burned to provide an aerosol and/or to heat an aerosol-forming material. See, for example, US Pat. Nos. 4,756,318 to

Clearman et al.; 4,714,082 to Banerjee et al.; 4,771,795 to White et al.; 4,793,365 to Sensabaugh et al.; 4,917,128 to Clearman et al.; 4,961,438 to orte; 4,966,171 to Serrano et al.; 4,969,476 to Bale et al.; 4,991,606 to Serrano et al.; 5,020,548 to Farrier et al; 5,033,483 to Clearman et al;

5,040,551 to Schlatter et al.; 5,050,621 to Creighton et al.; 5,065,776 to Lawson; 5,076,296 to Nystrom et al.; 5,076,297 to Farrier et al.; 5,099,861 to Clearman et al.; 5,105,835 to Drewett et al; 5,105,837 to Barnes et al; 5,1 15,820 to Hauser et al.; 5,148,821 to Best et al.; 5,159,940 to Hayward et al.; 5,178,167 to Riggs et al.; 5,183,062 to Clearman et al.; 5,211,684 to Shannon et al.; 5,240,014 to Deevi et al.; 5,240,016 to Nichols et al.; 5,345,955 to Clearman et al.; 5,551,451 to Riggs et al.; 5,595,577 to Bensalem et al.; 5,819,751 to Barnes et al.; 6,089,857 to Matsuura et al.; 6,095,152 to Beven et al; 6,578,584 to Beven; and 6,730,832 to Dominguez; which are

incorporated herein by reference. Furthermore, certain types of cigarettes that employ

carbonaceous fuel elements have been commercially marketed under the brand names "Premier" and "Eclipse" by R. J. Reynolds Tobacco Company. See, for example, those types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000). Addition types of aero sol- generating devices are described in US Pat. No. 7,726,320 to Robinson et al. and US Pat. Appl. Pub. Nos. 2006/0196518 and 2007/0267031, both to Hon, all of which are incorporated by reference herein.

The extracts of the invention can be incorporated into smokeless tobacco products, such as loose moist snuff (e.g., snus), loose dry snuff, chewing tobacco, pelletized tobacco pieces (e.g., having the shapes of pills, tablets, spheres, coins, beads, obloids or beans), extruded or formed tobacco strips, pieces, rods, cylinders or sticks, finely divided ground powders, finely divided or milled agglomerates of powdered pieces and components, flake-like pieces, molded processed tobacco pieces, pieces of tobacco-containing gum, rolls of tape-like films, readily water-dissolvable or water-dispersible films or strips (e.g., US Pat. App. Pub. No. 2006/0198873 to Chan et al.), or capsule-like materials possessing an outer shell (e.g., a pliable or hard outer shell that can be clear, colorless, translucent or highly colored in nature) and an inner region possessing tobacco or tobacco flavor (e.g., a Newtonian fluid or a thixotropic fluid incorporating tobacco of some form). Various types of smokeless tobacco products are set forth in US Pat. Nos. 1,376,586 to Schwartz; 3,696,917 to Levi; 4,513,756 to Pittman et al; 4,528,993 to Sensabaugh, Jr. et al.; 4,624,269 to Story et al.; 4,987,907 to Townsend; 5,092,352 to Sprinkle, III et al.; and 5,387,416 to White et al.; US Pat. App. Pub. Nos. 2005/0244521 to Strickland et al. and 2008/0196730 to Engstrom et al.; PCT WO 04/095959 to Arnarp et al.; PCT WO 05/063060 to Atchley et al.; PCT WO 05/016036 to Bjorkholm; and PCT WO 05/041699 to Quinter et al., each of which is incorporated herein by reference. See also, the types of smokeless tobacco formulations, ingredients, and processing methodologies set forth in US Pat. Nos. 6,953,040 to Atchley et al. and 7,032,601 to Atchley et al.; US Pat. Appl. Pub. Nos. 2002/0162562 to Williams; 2002/0162563 to Williams; 2003/0070687 to Atchley et al.; 2004/0020503 to Williams, 2005/0178398 to Breslin et al.; 2006/0191548 to Strickland et al; 2007/0062549 to Holton, Jr. et al.; 2007/0186941 to Holton, Jr. et al.;

2007/0186942 to Strickland et al.; 2008/0029110 to Dube et al.; 2008/0029116 to Robinson et al.; 2008/0029117 to Mua et al.; 2008/0173317 to Robinson et al; 2008/0209586 to Neilsen et al.; 2010/0018541 to Gerardi et al.; 2010/0018540 to Doolittle et al.; and 2010/0116281 to Marshall et al., each of which is incorporated herein by reference.

Referring to FIG. 2, a representative snus type of tobacco product comprising the extract of the present invention is shown. In particular, FIG. 2 illustrates a smokeless tobacco product 40 having a water-permeable outer pouch 42 containing a smokeless tobacco composition 44, wherein the tobacco composition includes a shredded or particulate tobacco material serving as a carrier for the extract of the invention.

Many exemplary smokeless tobacco compositions that can benefit from use of the extract of the invention comprise shredded or particulate tobacco material that can serve as a carrier for the flavorful extract of the invention. The smokeless tobacco compositions of the invention can also include a water-soluble polymeric binder material and optionally other ingredients that provide a dissolvable composition that will slowly disintegrate in the oral cavity during use. In certain embodiments, the smokeless tobacco composition can include lipid components that provide a meltable composition that melts (as opposed to merely dissolving) in the oral cavity, such as compositions set forth in US Appl. No. 12/854,342 to Cantrell et al., filed August 11, 2010, and which is incorporated by reference herein.

In one particular smokeless tobacco product embodiment, the extract of the invention is added to a non-tobacco plant material, such as a plant material selected from potato, beet (e.g., sugar beet), grain, pea, apple, and the like. The non-tobacco plant material can be used in a processed form. In certain preferred embodiments, the non-tobacco plant material can be used in an extracted form, and as such, at least a portion of certain solvent soluble components are removed from that material. The non-tobacco extracted plant material is typically highly extracted, meaning a substantial amount of the aqueous soluble portion of the plant material has been removed. For example, a water-extracted pulp can be obtained by extracting significant amounts of water soluble components from the plant material. For example, certain water-extracted plant materials can comprise less than about 20 weight percent, and often less than about 10 weight percent water soluble components; and depending upon processing conditions, certain water-extracted plant materials can be virtually free of water soluble components (e.g., less than about 1 weight percent water soluble components). One preferred water-extracted plant material is water extracted sugar beet pulp (e.g., water extracted sugar beet leaf pulp). The extracted non-tobacco plant material is typically used in a form that can be described as shredded, ground, granulated, fine particulate, or powder form. The dry weight ratio of non-tobacco plant material to tobacco extract of the invention is typically about 4:l to about 1 :4, about 2:l to about 1:2, and often about 1.5: 1 to about 1 :1.5. Smokeless tobacco products of this type are set forth in US Appl. No. 12/756,656 to Beeson et al, filed April 8, 2010, which is incorporated by reference herein.

Further additives can be admixed with, or otherwise incorporated within, the smokeless tobacco compositions according to the invention. The additives can be artificial, or can be obtained or derived from herbal or biological sources. Exemplary types of additives include salts (e.g., sodium chloride, potassium chloride, sodium citrate, potassium citrate, sodium acetate, potassium acetate, and the like), natural sweeteners (e.g., fructose, sucrose, glucose, maltose, vanillin, ethylvanillin glucoside, mannose, galactose, lactose, and the like), artificial sweeteners (e.g., sucralose, saccharin, aspartame, acesulfame K, neotame and the like), organic and inorganic fillers (e.g., grains, processed grains, puffed grains, maltodextrin, dextrose, calcium carbonate, calcium phosphate, corn starch, lactose, manitol, xylitol, sorbitol, finely divided cellulose, and the like), binders (e.g., povidone, sodium carboxymethylcellulose and other modified cellulosic types of binders, sodium alginate, xanthan gum, starch-based binders, gum arabic, lecithin, and the like), pH adjusters or buffering agents (e.g., metal hydroxides, preferably alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and other alkali metal buffers such as metal carbonates, preferably potassium carbonate or sodium carbonate, or metal bicarbonates such as sodium bicarbonate, and the like), colorants (e.g., dyes and pigments, including caramel coloring and titanium dioxide, and the like), humectants (e.g., glycerin, propylene glycol, and the like), oral care additives (e.g., thyme oil, eucalyptus oil, and zinc), preservatives (e.g., potassium sorbate, and the like), syrups (e.g., honey, high fructose corn syrup, and the like), disintegration aids (e.g., microcrystalline cellulose, croscarmellose sodium, crospovidone, sodium starch glycolate, pregelatinized corn starch, and the like), flavorant and flavoring mixtures, antioxidants, and mixtures thereof. If desired, the additive can be microencapsulated as set forth in US Patent Appl. Pub. No. 2008/0029110 to Dube et al., which is incorporated by reference herein.

The amount of tobacco extract that is added to a tobacco composition or tobacco product can vary, and will depend in part on the desired function of the extract, the chemical makeup of the extract, and the type of tobacco composition or product to which the extract is added. Unless otherwise indicated herein, the amount added to a tobacco product will typically not exceed about 25 weight percent based on the total dry weight of the tobacco composition to which the extract is added. When the extract is employed within a smoking article, the amount of extract will typically be at least about 5 ppm, generally at least about 10 ppm, and often at least about 100 ppm, based on the total dry weight of the tobacco material within the smoking article; but will typically be less than about 5 percent, generally less than about 2 percent, and often less than about 1 percent, based on the total dry weight of the tobacco material within the smoking article. When the extract is employed within a smokeless tobacco product, the amount of extract will typically be at least about 5 ppm, generally at least about 10 ppm, and often at least about 100 ppm, based on the total dry weight of the tobacco material within the smokeless tobacco product; but will typically be less than about 10 percent, generally less than about 5 percent, and often less than about 1 percent, based on the total dry weight of the tobacco material within the smokeless tobacco product.

EXPERIMENTAL

Aspects of the present invention are more fully illustrated by the following examples, which are set forth to illustrate certain aspects of the present invention and are not to be construed as limiting thereof. Unless otherwise noted, all parts and percentages are by weight.

Example 1

A fire-cured tobacco is extracted using water. A typical extraction process combines milled tobacco (e.g., 100% pass 0.250 inch screen) with water at a ratio of 8 parts water to 1 part tobacco at a temperature of about 72 °C. The mixture is agitated for one hour and the suspended solids removed by filtration using a 5 micron filter bag. The resulting tobacco extract retains the aroma and sensory characteristics of the fire-cured tobacco. The original fire-cured tobacco has a BaP level prior to extraction of about 150 to 800 parts per billion and the separated liquid extract has a BaP level of less than about 1 part per billion.

Example 2

An air-cured tobacco is subjected to the same extraction process as set forth in Example 1. The original air-cured tobacco has a BaP level prior to extraction of about 10-150 parts per billion and the separated liquid extract has a BaP level of less than about 1 part per billion.

Example 3

Ground fire-cured tobacco having a moisture content of 10% is extracted using supercritical C0₂. An exemplary extraction process employs a Jasco supercritical fluid extraction system, comprising preparation pumps, column thermostat, photodiode array detector, HPLC pump, automatic back pressure regulator, and 6-valve change unit capable of collecting samples in a time sequence manner during a single extraction run. A stainless steel pressure extraction vessel is located inside the column thermostat, with a pressure limit of 40 MPa. The extractions are conducted using 100% C0₂ and methanol is used as the back flow to trap extracted compounds.

The pressure, temperature, and C0₂ flow rate with which the extraction is conducted are varied to assess the effects of each on the removal of B[a]p and TSNA from the tobacco. Pressure is held at 10, 20, or 30 MPa, temperature is held at either 40 °C or 60 °C, and C0₂ flow rate is set at 5 or 10 mL/min. The resulting solid residues are extracted with hexanes and subjected to liquid chromatography to evaluate B[a]p and TSNA concentrations of the extracted material as compared with those of unextr acted tobacco.

At higher temperatures and lower pressures, only a small decrease in B[a]p (~5% reduction) and TSNA (less than about 20% reduction) are observed. Increasing the pressure at which the extraction is conducted provides comparable results. The highest TSNA reduction is obtained using moderate (20 MPa) pressure, a temperature of 60 °C, and a flow rate of 10 mL/min. The highest B[a]p reduction (62% reduction) is obtained using a pressure of 30 MPa, a temperature of 60 °C, and a flow rate of 10 mL/min.

Example 4

Water-extracted fire cured tobacco pulp having a moisture content of 11% is extracted using supercritical C0₂ using the method described in Example 3. The C0₂ flow rate is set at 10 mL/min and the temperature is set at 40 °C or 60 °C and pressure is set at 10, 20, or 30 MPa to evaluate the effect of temperature and pressure on the removal of B[a]p and TSNA from water-extracted fire- cured tobacco.

As temperature and pressure are increased, more B[a]p and TSNA are removed from the tobacco. However, at a pressure of 10 MPa, increasing the temperature from 40 °C to 60 °C does not have much of an effect on the removal of B[a]p or TSNA from water-extracted fire-cured tobacco. The highest TSNA reduction (63%) is obtained using a pressure of 30 MPa, and a temperature of 60 °C. The highest B[a]p reduction (46% and 47%, respectively) is obtained using a pressure of 30 MPa with a temperature of either 40 °C or 60 °C.

Example 5

Ground fire-cured tobacco with a moisture content of 10% is extracted using supercritical

C0₂ as described in Example 3. The pressure is held at 20 MPa, the temperature is held at 40 °C, and the flow rate is held at 10 mL/min C0₂. The extraction time is varied to assess the effect of extraction time on the removal of B[a]p and TSNA. Extractions are conducted over periods of 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes. The decrease in B[a]p and TSNA observed with the sample that was subjected to extraction for 30 minutes is comparable to that observed with samples subjected to extraction for longer than 30 minutes; therefore, 30 minutes is selected as the extraction duration for remaining experiments.

Water-extracted fire-cured tobacco pulp with a moisture content of 11 % is similarly extracted using various extraction times. Again, an extraction time of 30 minutes results in sufficient removal of both B[a]p and TSNA.

Example 6

Various fire-cured and water-extracted fire cured tobacco pulp samples are extracted using supercritical C0₂ as described in Example 3. The moisture content of the tobacco samples prior to extraction is varied to evaluate the effect of moisture on the removal of B[a]p and TSNA. The pressure is held at 20 MPa, the temperature is held at 40 °C, the flow rate is 10 mL/min C0₂, and the run time is 30 minutes. Varying levels of moisture are added to tobacco samples prior to extraction, to give fire-cured tobacco samples having 10%, 16%, 21%, 25%, and 31% moisture content and water-extracted fire-cured tobacco samples having 10%, 11%, 16%, 21%, and 27% moisture content. The actual amounts of tobacco samples charged into the extraction vessels are calculated based on moisture content to achieve the same amount (10 g) of oven-dried weight such that each sample subjected to the extraction initially contains the same overall amount of tobacco. Each sample is extracted and the resulting solid residues are air-dried for at least 4 days to bring the moisture content of each sample residue to relatively the same level.

For the fire-cured tobacco, increasing the moisture content from 10% to 31 % results in greater TSNA reduction (from 60% TSNA reduction at 10% moisture content to 80% TSNA reduction at 31% moisture content) and greater B[a]p reduction (from 45% B[a]p reduction at 10% moisture content to 80% B[a]p reduction at 31% moisture content).

For the water-extracted fire-cured tobacco, increasing the moisture content from 10% to

27% similarly results in a greater TSNA reduction (45% TSNA reduction at 10% moisture content to 80% TSNA reduction at 27% moisture content) and a greater B[a]p reduction (20% B[a]p reduction at 10% moisture content to 50% B[a]p reduction at 27% moisture content).

Seemingly, introduction of moisture to the tobacco material facilitates the removal of both B[a]p and TSNA. Although not intended to be limiting of the invention, one explanation is that the addition of water may open the internal structure of the tobacco, leaving it more accessible for extraction. One other explanation is that, because B[a]p is non-polar, the presence of more water in the tobacco more effectively "pushes" the B[a]p out of the tobacco. TSNA has both polar and non- polar features and thus, this theory may explain the increase in both B[a]p and TSNA removal as the moisture level of the tobacco is increased.

Example 7

Various lire-cured and water-extracted fire cured tobacco pulp samples are extracted using supercritical C0₂ as described in Example 3. Varying amounts of ethanol are added to act as a modifier for the supercritical C0₂to evaluate the effect of ethanol on the removal of B[a]p and TSNA. Temperature and pressure are also varied to evaluate the effect of these parameters with the addition of ethanol to the extraction system.

The pressure is held at 10 or 20 MPa, the temperature is held at 40 °C or 60 °C, the flow rate is 10 mL/min C0₂, and the run time is 30 minutes. Varying amounts of ethanol are added to the C0₂ used to conduct extraction of the tobacco samples. Specifically, the extraction media evaluated are: 100% C0₂, C0₂ with 10% ethanol by weight, and C0₂ with 30% ethanol by volume.

Extractions of both water-extracted and fire-cured tobacco and fire-cured tobacco are conducted with each of these extraction media. Extractions are conducted at temperatures of 40 °C and 60 °C and at pressures of 10 MPa and 20 MPa with each extraction medium. Each sample is extracted and the resulting solid residues are evaluated to determine the reduction in B[a]p and TSNA. For both the fire-cured tobacco and the water-extracted fire-cured tobacco, adding ethanol results in a greater reduction in both B[a]p and TSNA under all temperature and pressure conditions evaluated.

For example, at 60 °C and 10 MPa, extraction of water-extracted fire-cured tobacco with C0₂ alone results in a 20% reduction in B[a]p and a 32% reduction in TSNA, whereas extraction with 30%) ethanol in C0₂ results in a 71% reduction in B[a]p and a 79% reduction in TSNA. Under the same conditions, extraction of fire-cured tobacco with C0₂ alone results in a 37% reduction in B[a]p and a 46% reduction in TSNA, whereas extraction with 30% ethanol in C0₂ results in an 80% reduction in B[a]p and a 75%> reduction in TSNA.

The highest level of B[a]p reduction (74%) in water-extracted fire-cured tobacco in this example is achieved with an extraction medium of 30% ethanol in C0₂ at a temperature of 60 °C and a pressure of 20 MPa. The highest level of TSNA reduction (79%) in water-extracted fire- cured tobacco in this example is achieved with an extraction medium of 30% ethanol in C0₂ at a temperature of 60 °C and a pressure of either 10 or 20 MPa.

The highest level of B[a]p reduction (80%) in fire-cured tobacco in this example is achieved with an extraction medium of 30% ethanol in C0₂ at a temperature of 60 °C and a pressure of 10 MPa. The highest level of TSNA reduction (75%) in fire-cured tobacco in this example is achieved with an extraction medium of 30% ethanol in C0₂ at a temperature of 60 °C and a pressure of 10 MPa.

Generally, adding ethanol up to about 30% by volume to C0₂ for use as the extraction medium increases the removal of both B[a]P and TSNA. Varying the temperature of such extractions from 40 °C to 60 °C has little effect, although in certain cases, it can result in slightly enhanced B[a]P and TSNA removal. Similarly, increasing the pressure of such extractions from 10 MPa to 20 MPa has little effect, although in certain cases, it can result in slightly enhanced B[a]P and TSNA removal.

Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing description. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WE CLAIM:

1. A method of producing a tobacco composition for use in a tobacco product, the tobacco composition characterized by a reduced benzo[a]pyrene concentration, comprising:

mixing an extracted pulp of a cured tobacco material having a first benzo[a]pyrene concentration with supercritical carbon dioxide to provide intimate contact between the extracted pulp and the supercritical carbon dioxide;

maintaining the intimate contact for a time and at a temperature sufficient to form a treated tobacco pulp exhibiting a second benzo[a]pyrene concentration lower than the first benzo[a]pyrene concentration; and

separating the treated tobacco pulp from a residual supercritical carbon dioxide extract comprising components of the tobacco material that are soluble in the supercritical carbon dioxide.

2. The method of claim 1, wherein the cured tobacco material of the extracted pulp comprises ground fire-cured tobacco.

3. The method of claim 2, wherein the extracted pulp is an aqueous extracted tobacco material.

4. The method of claim 1, wherein the pressure at which the mixing is conducted is about 10 MPa or greater.

5. The method of claim 1, wherein the pressure at which the mixing is conducted is about 20 MPa or greater.

6. The method of claim 1, wherein the pressure at which the mixing is conducted is between about 10 MPa and about 40 MPa.

7. The method of claim 1, wherein the temperature at which the mixing is conducted is about 40 °C or greater.

8. The method of claim 1 , wherein the temperature at which the mixing is conducted is about 50 °C or greater.

9. The method of claim 1 , wherein the temperature at which the mixing is conducted is between about 40 °C and about 60 °C.

10. The method of claim 1, wherein the mixing is conducted for a period of at least about 15 minutes.

11. The method of claim 1 , wherein the mixing is conducted for a period of at least about 30 minutes.

12. The method of claim 1, wherein the mixing step comprises mixing the extracted pulp with supercritical carbon dioxide and ethanol.

13. The method of claim 12, wherein the ethanol is present in an amount of about 10% to about 30% by volume of the supercritical carbon dioxide and ethanol.

14. The method of claim 1, wherein the first benzo[a]pyrene concentration is at least about 200 ng/g and the second benzo[a]pyrene concentration is less than about 80 ng/g.

15. The method of claim 1 , wherein the TSNA concentration of the treated tobacco pulp is less than that of the extracted pulp of cured tobacco material.

16. The method of claim 15, wherein the extracted pulp of cured tobacco material has a TSNA concentration of greater than about 5,000 ng/g and the treated tobacco pulp has a TSNA concentration of less than about 2,000 ng/g.

17. The method of claim 1, further comprising adding a tobacco extract to the treated tobacco pulp to form a tobacco composition.

18. The method of claim 17, wherein the tobacco extract is an aqueous extract.

19. The method of claim 17, wherein the tobacco extract and the treated tobacco pulp are derived from the same tobacco sample.

20. The method of claim 1, wherein the cured tobacco material of the extracted pulp comprises fire-cured tobacco material, and wherein the method further comprises adding an aqueous fire-cured tobacco extract to the treated tobacco pulp to form a tobacco composition.

21. The method of any of claims 1-20, further comprising introducing the treated tobacco pulp into a tobacco product.

22. The method of claim 21, wherein the tobacco product is selected from the group consisting of smoking articles, smokeless tobacco products, and aerosol-generating devices configured for non-combustion of plant material.

23. The method of claim 21, wherein the tobacco product is a smokeless tobacco composition selected from the group consisting of moist snuff, dry snuff, chewing tobacco, tobacco-containing gums, and dissolvable or meltable tobacco products.

24. A tobacco product comprising an extracted pulp of a cured tobacco material, wherein the extracted pulp of cured tobacco material is characterized as having a B[a]p concentration of less than about 80 ng/g.

25. The tobacco product of claim 24, wherein the extracted pulp is characterized as having a

TSNA concentration of less than about 2,000 ng/g.

26. The tobacco product of claim 24, further comprising a tobacco extract carried by the extracted pulp.

27. The tobacco product of claim 26, wherein the tobacco extract is an aqueous extract.

28. The tobacco product of claim 26, wherein the tobacco extract and the extracted pulp of cured tobacco material are derived from the same tobacco sample.

29. The tobacco product of claim 24, wherein the cured tobacco material of the extracted pulp comprises fire-cured tobacco material, and wherein the tobacco product further comprises an aqueous fire-cured tobacco extract carried by the extracted pulp.

30. The tobacco product of claim 24, wherein the tobacco product is in the form of a smokeless tobacco composition, a smoking article, or an aerosol-generating device configured for non-combustion of plant material.

31. The tobacco product of claim 30, wherein the tobacco product is in the form of a smokeless tobacco composition selected from the group consisting of moist snuff, dry snuff, chewing tobacco, tobacco-containing gums, and dissolvable or meltable tobacco products.