Dried leaf tobacco and smoking article

Abstract

This dried leaf tobacco is obtained as a result of being dried so as to exhibit a green color. The dried leaf tobacco preferably has an a* value of -2 or less as measured according to the L*a*b* method standardized by CIE 1976.

Description

Dry-cured tobacco and smoking articles

[0001] The present invention relates to flue-cured tobacco and smoking articles.

[0002] In non-combustible smoking articles, flavor components are generally distilled and delivered together with the aerosol by heating a tobacco rod to approximately 150° C. to 350° C. In other words, for non-combustible smoking articles, a tobacco raw material that effectively expresses flavor and aroma in the temperature range of 150° C. to 350° C. is desired.

[0003] Tobacco raw materials used in non-combustible smoking articles are generally those that have traditionally been used in combustible tobacco. Known tobacco raw materials are classified into several types, including Virginia, Burley, and Orient. Virginia is a tobacco raw material with a rich aroma and is often used in combustible tobacco products known as Virginia Blend. Burley has a strong flavor and is used in combustible tobacco products known as American Blend. Orient has a distinctive flavor and can balance the taste and aroma of the entire blend.

[0004] The quality of the raw materials described above is largely determined by the variety and cultivation method, but also by post-harvest processing methods, such as curing. Over the long history of tobacco culture, curing methods tailored to each variety have been thoroughly explored, and today, drying methods suited to each variety have been established. After harvest, Virginia varieties undergo a process called flue-curing. Specifically, they are dried for 5 to 7 days in a temperature- and humidity-controlled environment, typically with the temperature gradually increased to 30 to 70°C (Non-Patent Documents 1 and 2). After harvest, Burley varieties undergo a process called air-curing. Specifically, they are dried for 30 to 40 days at approximately natural ambient temperature, away from direct sunlight (Non-Patent Document 3). After harvest, Orient varieties are shade-dried for one day, then exposed to sunlight for a process called sun / air-curing. Depending on the variety, they may then undergo a fermentation process (Non-Patent Document 4).

[0005] As such, the drying methods and conditions for leaf tobacco vary greatly depending on the variety. The appearance quality also differs depending on the variety, due in part to differences in curing. For example, dried Virginia varieties are yellowish-brown in color. Dried Burley varieties are deep brown in color. Dried Oriental varieties vary further depending on the cultivar, but are often slightly greenish-brown in color.

[0006] In the United States, scientific elucidation of quality changes during curing was undertaken between the 1930s and 1950s. This was summarized in a review by Frankenburg et al. (Non-Patent Document 5). It is believed that changes during the early stages of curing are primarily due to changes in plant respiration and changes in chemical components caused by residual enzyme activity after cell death. Typical changes in components include protein hydrolysis, which is accompanied by increases in some amino acids and soluble nitrogen components such as ammonia (Non-Patent Document 6). Starch is hydrolyzed and converted into low-molecular-weight sugars, including monosaccharides (Non-Patent Document 2). These reactions occur due to the loss of the counterbalance that would normally occur in growing tobacco leaves. In other words, the metabolism of these components is fundamentally different from that during growth. Simultaneously with the hydrolysis reaction, various components also change through oxidation. As curing progresses, the dynamic equilibrium of the plant's natural redox system is lost, resulting in significant oxidation of many of the components in tobacco leaves. Carbohydrates and organic acids are oxidized under the influence of a series of enzymes previously involved in the respiratory system in living plants (Non-Patent Documents 7 and 8). In addition, phenolic and polyphenolic compounds and terpenoid compounds are also decomposed by oxidation (Non-Patent Documents 9-11). As mentioned above, there are several methods for curing tobacco depending on the variety and purpose. Among these, air-curing actively induces oxidation reactions of chemical components. On the other hand, fluid-curing is designed to minimize the effects of oxidation.

[0007] Peedin, G. F.: Production practices: Flue-cured tobacco, p. 104-142. In Tobacco: Production Chemistry and Technology, Davis, D. L., Nielsen, M. T., Eds.; Blackwell Science: Oxford, U.K. (1999)Abubakar, Y., Young, J. H., Johnson, W. H., and Weeks, W. W.: Changes in moisture and chemical composition of flue-cured tobacco during curing. Tob. Sci., 44, 51-58 (2000)Palmer, G. K., and Pearce, R. C.: Production practices: Light air-cured tobacco, p. 143-153. In Tobacco: Production Chemistry and Technology, Davis, D. L., Nielsen, M. T., Eds.; Blackwell Science: Oxford, U.K. (1999)Gilchrist, S. N.: Production practices: Oriental tobacco, p. 154-163. In Tobacco: Production Chemistry and Technology, Davis, D. L., Nielsen, M. T., Eds.; Blackwell Science: Oxford, U.K. (1999)Frankenburg, W. G.: Chemical Changes in the Harvested Tobacco Leaf. I. Chemical and Enzymatic Conversations during the Curing Process. Advances in Enzymolozy, Volume VI, 6, 309-387 (1946)Young, J. R., and Jeffrey, R. N.: Changes in certain water-soluble nitrogenous constituents of burley tobacco during storage. Plant Plysiol., 18, 433-438 (1943)Pucher, G. W., and Vickery, H. B.: The metabolism of the organic acids of tobacco leaves; effect of culture of excised leaves in solutions of organic acid salts. J. Biol. Chem., 178, 557-575 (1949)Vickert, H. B., and Abrahams, M. D.: The metabolism of the organic acids of tobacco leaves; effect of culture of excised leaves in solutions of d-isocitrate and acetate. J. Biol. Chem., 180, 37-45 (1949)Sheen, S. J., and Calvert, J.: Studies on polyphenol content, activities and isozymes of polyphenol oxidase and peroxidase during air-curing in three tobacco types. Plant Physiol., 44, 199-204 (1969)Weston, T. J.: Biochemical characteristics of tobacco leaves during flue-curing. Phytochemistry, 7, 921-930 (1968)Wahlberg, I., Kerstin, K., Austin, D. J., Junker, D., Roeraade, J., Enzell, C. R., and Johnson, W. H.: Effects of flue-curing and aging on the volatile, neutral and acidic constituents of Virginia tobacco. Phytochemistry, 16, 1217-1231 (1977).

[0008] Based on a long history of research and experience, the technology of adjusting the drying process of tobacco leaves to produce dried leaves of the desired quality, i.e., curing technology, has been passed down to the present day. However, this quality is assumed to be applied to combustible smoking articles, and is not necessarily optimal for non-combustible smoking articles. Conversely, even raw materials that are considered unsuitable for combustible smoking articles may have unexpected effects when used in non-combustible smoking articles. In light of these circumstances, an objective of the present invention is to provide dried tobacco leaves that are suitable for non-combustible smoking articles.

[0009] Conventionally, tobacco leaves have been dried until brown before use. However, the inventors have found that while this drying reduces the components suitable for non-combustible smoking articles, specific drying methods prevent the loss of these components. That is, the above-mentioned problems are solved by the following inventions. Aspect 1: Dry-dried tobacco leaves obtained by drying to a green color. Aspect 2: L standardized by CIE 1976. ＊ a ＊ b ＊ a measured according to the method ＊Aspect 3: The cured leaf tobacco according to Aspect 1, wherein the value of the moisture content is -2 or less. Aspect 4: The cured leaf tobacco according to Aspect 1 or 2, wherein the drying step comprises placing the harvested fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll portion is 25% by weight or less. Aspect 5: The cured leaf tobacco according to any one of Aspects 1 to 4, wherein the drying step comprises placing the harvested fresh leaves in an environment of 30 to 40°C and a relative humidity of 60 to 70% for 6 to 12 hours, and then placing the harvested fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll portion is 25% by weight or less. Aspect 6: The cured leaf tobacco according to any one of Aspects 1 to 5, wherein the cured leaf tobacco is a Nicotiana tabacum. Aspect 7: The cured leaf tobacco according to any one of Aspects 1 to 6, wherein the cured leaf tobacco is a Burley variety. Aspect 8: A tobacco composition comprising the cured leaf tobacco according to any one of Aspects 1 to 7, wherein the composition comprises 5 to 90% by weight of the cured leaf tobacco. Aspect 9: The composition according to Aspect 8, further comprising 3 to 30% by weight of an aerosol source. Aspect 10: The composition according to Aspect 9, wherein the aerosol source is selected from the group consisting of glycerin, propylene glycol, 1,3-propanediol, and combinations thereof. Aspect 11: The composition according to any one of Aspects 8 to 10, further comprising 5 to 85% by weight of reconstituted tobacco shreds, or 5 to 85% by weight of tobacco shreds. Aspect 12: The composition according to any one of Aspects 8 to 11, further comprising a non-tobacco flavoring agent. Aspect 13: The composition according to Aspect 12, wherein the non-tobacco flavoring agent is selected from the group consisting of a flavoring, a cooling agent, and a combination thereof. Aspect 14: The composition according to Aspect 13, wherein the flavoring is menthol. Aspect 15: A non-combustion heating smoking article comprising the cured leaf tobacco according to any one of Aspects 1 to 9 or the composition according to any one of Aspects 8 to 14.

[0010] The present invention provides dried tobacco leaf suitable for non-combustible smoking articles.

[0011] FIG. 1 is a diagram showing one embodiment of a non-combustion heating smoking article; FIG. 2 is a diagram showing one embodiment of a non-combustion heating smoking system; FIG. 3 is a diagram explaining a method for producing dried tobacco; and FIG. 4 is a diagram explaining the steps in a comparative example and an example.

[0012] In this disclosure, "X to Y" includes the end values ​​X and Y. Furthermore, unless otherwise specified in this disclosure, weight means bone dry weight.

[0013] 1. Cured Leaf Tobacco The cured leaf tobacco according to this embodiment is obtained by drying harvested tobacco leaves (fresh leaves) so that they retain a green color. By drying the harvested tobacco leaves so that they retain a green color, it is possible to avoid a decrease in components suitable for non-combustible smoking articles. The cured leaf tobacco may be the dried leaves themselves, or the mesophyll portion separated from the dried leaves.

[0014] The color tone of the dried leaf tobacco is not limited as long as it is visually recognizable as green. ＊ a ＊ b ＊ a measured according to the method ＊ The value is preferably −2 or less. ＊ The value is more preferably −4 or less. ＊ There is no lower limit to the value, but it is preferably −8 or more. ＊ The value corresponds to a position between magenta and green, with larger values ​​being closer to magenta and smaller values ​​being closer to green.

[0015] L ＊ Value, a ＊ value, b ＊ The value can be measured on the surface of tobacco leaves using a spectrophotometer (e.g., KONICA MINOLTA / CM3500d, Konica Minolta Holdings, Inc.) Specifically, standard light (standard illuminant D65 for colorimetry, CIE, ISO reference light) is irradiated onto the surface of tobacco leaves, and the reflected light is measured (reflected color measurement / specular reflection excluded method (SCE)). ＊ The color definitions are based on the International Commission on Illumination (CIE) and JIS.

[0016] In one embodiment, a component suitable for non-combustible smoking articles (hereinafter also referred to as "component H") has a retention index (RI) of 1800 to 3100 in gas chromatography. Component H expresses the original aroma of tobacco. Component H is a component group including partial degradation products of chlorophyll, leaf resin, higher fatty acids, and higher hydrocarbons. Specifically, component H includes neophytadiene (RI = 1842), phytol (RI = 2114), α-cembratriene diol (α-CBT, RI = 2242), linoleic acid (RI = 2145), etc. On the other hand, a component having an RI of 1365 or more but less than 1800 (hereinafter also referred to as "component L") is a component group including degradation products of cembratriene and degradation products of carotenoids. Component L includes 3-oxo-α-ionone (RI=1648), solanone (RI=1368), norsolanadione (RI=1489), megastigmatrienone (RI=1581), and the like.

[0017] RI can be determined by a known method using a standard saturated alkane standard, but is preferably determined by the following method. 1) A standard saturated alkane standard (for example, C7-C40 manufactured by Merck) is diluted with hexane to use hexane (C6) to tetracontane (C40) as the index. 2) The linear retention index is determined based on the following formula and used as the RI. RI = 100 x {[(tr(unknown) - tr(n)] / [tr(N) - tr(n)] + n} n = number of carbon atoms in the n-alkane eluting immediately before the unknown component N = number of carbon atoms in the n-alkane eluting immediately after the unknown component tr = retention time

[0018] The dried leaf tobacco is preferably Nicotiana tabacum, more preferably Burley. Burley has a low sugar content, which reduces the generation of a cereal-like aroma. Non-combustion heated smoking articles emit a distinctive cereal-like aroma when in use. It is preferable to suppress this aroma. One of the causes of the cereal-like aroma is glycolysis. When heated, sugar generates pyrolysis components, such as furans. That is, if the sugar content in dried leaf tobacco is high, the cereal-like aroma can increase. During the drying process of fresh leaves, catabolism occurs, increasing the amount of sugars, which can result in the generation of a cereal-like aroma. However, using burley can suppress the cereal-like aroma.

[0019] 2. Method for Producing Cured Leaf Tobacco The cured leaf tobacco according to this embodiment is obtained by drying fresh leaves after harvesting under conditions that result in a green color. However, drying fresh leaves at a high temperature from the beginning tends to result in browned cured leaf tobacco. The reason for this is not limited, but sudden exposure to high temperatures destroys the cells of the fresh leaves, causing an enzyme that oxidizes component H in the fresh leaves to leak out of the cells. It is presumed that this enzyme reacts with component H, resulting in the oxidation of component H. Therefore, it is preferable to perform drying in stages.

[0020] In one aspect, the drying step preferably includes a step of placing fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll portion is reduced to 25% by weight or less (low-temperature drying step). Drying at such a low temperature prevents cell destruction in the fresh leaves, making Component H less likely to be oxidized and less likely to brown. The upper limit of the target moisture content of the mesophyll portion (hereinafter also referred to as "target moisture content") is preferably 20% by weight or less. The lower limit of the target moisture content is not limited, but is preferably 15% by weight or more. The lower limit of the temperature is not limited, but is preferably 35°C or more from the viewpoint of work efficiency, etc. The humidity is not limited, but is preferably 30 to 40% relative humidity (30 to 40% RH).

[0021] The dried tobacco leaves obtained in the low-temperature drying step are preferably dried in an environment of 65-75°C and 15-25% RH to reduce the moisture content of the mesophyll to 12% by weight or less (high-temperature drying step). This embodiment is shown in Figure 3 (1). The high-temperature drying step exposes the mesophyll and vein portions to high temperatures, but because moisture has already been removed from the mesophyll, the enzymatic oxidation of component H and browning are suppressed. The upper limit of the target moisture content in this step can be set to 10% by weight or less. However, because excessive drying may induce decomposition of component H, the lower limit of the moisture content of the mesophyll is preferably 8% by weight or more. The temperature is preferably 67-70°C. The humidity is preferably 17-23% RH.

[0022] After this process, the mesophyll portion and the vein portion may be separated, and the mesophyll portion may be used as cured leaf tobacco. Curing the mesophyll portion into cured leaf tobacco at a stage where the moisture content of the mesophyll portion is reduced to 12% by weight or less in this manner can prevent discoloration of the mesophyll portion. This is for the following reason. Typically, the mesophyll portion dries first during the drying process of tobacco leaves, and at this stage the vein portion contains a large amount of moisture. Continuing heat drying until the vein portion is dry will cause discoloration of the mesophyll portion. However, separating the mesophyll portion with priority given to drying the mesophyll portion can prevent discoloration of the mesophyll portion. Furthermore, separating the mesophyll portion with priority given to drying the mesophyll portion can prevent spoilage or deterioration of the leaf tobacco due to moisture remaining in the mesophyll portion during processes after the tobacco is unloaded, i.e., during packaging, storage, and distribution.

[0023] The dried leaf tobacco obtained in the high-temperature drying step is preferably conditioned. The conditions for humidification are not limited, but are preferably 20-25°C and 50-70% RH. Conditioning the humidity can prevent the leaf tobacco from being crushed during unloading and packaging. From this perspective, the temperature is preferably 21-23°C. The humidity is preferably 55-65% RH. A preferred embodiment including the humidification step is shown in Figure 3 (2).

[0024] Before the low-temperature drying step, a step of conditioning the humidity of the fresh leaves at a temperature of 30 to 40°C and a relative humidity of 60 to 70% (pretreatment step) may be carried out. By carrying out the pretreatment, the changes in components due to the cell destruction described above can be further suppressed. From this perspective, the temperature is preferably 32 to 38°C. The humidity is preferably 62 to 67% relative humidity. A preferred embodiment including the humidity conditioning step is shown in Figure 3 (3).

[0025] 3. Tobacco Composition The dried leaf tobacco is useful as a tobacco composition. The composition preferably contains 5 to 90 wt %, more preferably 30 to 70 wt %, of dried leaf tobacco (hereinafter also referred to as "component (A)").

[0026] (1) Tobacco material other than the dried leaf tobacco (hereinafter also referred to as "component (B)") The tobacco composition may contain a tobacco material other than the dried leaf tobacco (component (B)). Component (B) is not limited as long as it is a material derived from a Nicotiana plant. Specific examples of component (B) include tobacco shreds, tobacco powder, tobacco sheets, and strands, which are commonly used in the relevant field. These are used alone or in combination. Among these, from the viewpoint of excellent miscibility with component (A), component (B) is preferably tobacco shreds, reconstituted tobacco shreds, or cut tobacco sheets.

[0027] As the tobacco leaf used in component (B), species of the genus Nicotiana, such as Tabacum and Rustica, can be suitably used. There are no particular restrictions on the variety, and known varieties such as burley or flue-cured tobacco can be used. One or more of these tobacco leaf varieties can be mixed and used. The mixture can be a blend of the aforementioned varieties to achieve the desired flavor.

[0028] In the composition, the amount of component (B) is preferably 5 to 85% by weight, more preferably 25 to 65% by weight.

[0029] (2) Aerosol Source (hereinafter also referred to as "Component (C)") The tobacco composition may contain an aerosol source (component (C)). Component (C) is a material that vaporizes when heated and cools to generate an aerosol, or that generates an aerosol by atomization. When the composition contains an aerosol source, a sufficient amount of smoke can be achieved. Known aerosol sources can be used, and examples include polyhydric alcohols such as glycerin, vegetable glycerin, propylene glycol (PG), and 1,3-propanediol, triethyl citrate (TEC), and triacetin. The aerosol source is preferably selected from the group consisting of glycerin, propylene glycol, 1,3-propanediol, and combinations thereof. The amount of the aerosol source in the composition is preferably 3 to 30% by weight, more preferably 10 to 15% by weight. If the amount of the aerosol source exceeds the upper limit, stains or the like may occur on the tobacco segments, while if it is below the lower limit, the perceived smoke intensity may be reduced.

[0030] (3) Non-Tobacco Flavoring Agent (hereinafter also referred to as "Component (D)") The tobacco composition may further contain a non-tobacco flavoring agent (component (D)). A non-tobacco flavoring agent is a flavoring agent that is not derived from tobacco. Examples thereof include flavoring agents, cooling agents, and combinations thereof. Known flavoring agents and cooling agents can be used.

[0031] In particular, the following fragrances can be used alone or in combination: acetanisole, acetophenone, acetylpyrazine, 2-acetylthiazole, alfalfa extract, amyl alcohol, amyl butyrate, trans-anethole, star anise oil, apple juice, Peru balsam oil, beeswax absolute, benzaldehyde, benzoin resinoid, benzyl alcohol, benzyl benzoate, benzyl phenylacetate, benzyl propionate, 2,3-butanedione, 2-butanol, butyl butyrate, butyric acid, caramel, cardamom oil, carob absolute, β-carotene, carrot juice, L-carvone, β-caryophyllene, cassia bark oil, cedarwood oil, celery seed oil, chamomile oil, cinnamaldehyde, cinnamic acid, cinnamyl alcohol, cinnamyl cinnamate, citronella oil, DL-citronellol, and clary sage extract. Lacto, cocoa, coffee, konjac oil, coriander oil, cumin aldehyde, davana oil, δ-decalactone, γ-decalactone, decanoic acid, dill herb oil, 3,4-dimethyl-1,2-cyclopentanedione, 4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one, 3,7-dimethyl-6-octenoic acid, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, ethyl 2-methylbutyrate, ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl isovalerate, ethyl lactate, ethyl laurate, ethyl levulinate, ethyl maltol, ethyl octanoate, ethyl oleate, ethyl palmitate, ethyl phenylacetate, ethyl propionate, ethyl stearate, ethyl valerate, ethyl vanillin, ethyl vanillin glucoside, 2-ethyl-3,(5 or 6)-dimethylpyrazine, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, 2-ethyl-3-methylpyrazine, eucalyptol, fenugreek absolute, gene absolute, gentian root infusion, geraniol, geranyl acetate, grape juice, guaiacol, guava extract, gamma-heptalactone, gamma-hexalactone, hexanoic acid, cis-3-hexen-1-ol, hexyl acetate, hexyl alcohol, phenylhexyl acetate, honey, 4-hydroxy-3-pentenoic acid, lauryl methylpropional Ingredients: methicone, 4-hydroxy-4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexen-1-one, 4-(para-hydroxyphenyl)-2-butanone, sodium 4-hydroxyundecanoate, immortelle absolute, beta-ionone, isoamyl acetate, isoamyl butyrate, isoamyl phenylacetate, isobutyl acetate, isobutyl phenylacetate, jasmine absolute, cola nut tincture, labdanum oil, lemon terpeneless oil, licorice extract, linalool, linalyl acetate, robertia jasmine Orris root oil, maltol, maple syrup, menthol, menthone, L-menthyl acetate, para-methoxybenzaldehyde, methyl 2-pyrrolyl ketone, methyl anthranilate, methyl phenylacetate, methyl salicylate, 4'-methylacetophenone, methylcyclopentenolone, 3-methylvaleric acid, mimosa absolute, honey, myristic acid, nerol, nerolidol, gamma-nonalactone, nutmeg oil, delta-octalactone, octanal, octanoic acid, orange flower oil, orange oil, orris root oil, palmitic acid, omega-pentadeca Calactone, peppermint oil, petitgrain Paraguay oil, phenethyl alcohol, phenethyl phenylacetate, phenylacetic acid, piperonal, plum extract, propenylguaethol, propyl acetate, 3-propylidenephthalide, prune juice, pyruvic acid, raisin extract, rose oil, rum, sage oil, sandalwood oil, spearmint oil, styrax absolute, marigold oil, tea distillate, α-terpineol, terpinyl acetate, 5,6,7,8-tetrahydroquinoxaline, 1,5,5,9-tetramethyl-13-oxacyclo(8.3.0.0(4.9))tridecane, 2,3,5,6-tetramethylpyrazine, thyme oil, tomato extract, 2-tridecanone, triethyl citrate, 4-(2,6,6-trimethyl-1-cyclohexenyl)2-buten-4-one, 2,6,6-trimethyl-2-cyclohexene-1,4-dione, 4-(2,6,6-trimethyl (1,3-cyclohexadienyl)2-buten-4-one, 2,3,5-trimethylpyrazine, γ-undecalactone, γ-valerolactone, vanilla extract, vanillin, veratraldehyde, violet leaf absolute, N-ethyl-p-menthane-3-carboxamide (WS-3), ethyl-2-(p-menthane-3-carboxamide)acetate (WS-5).

[0032] Among these, menthol is preferred. Ordinary tobacco materials contain a relatively large amount of a component (component L) with an RI of 1600 or less. Therefore, in ordinary tobacco materials, component L interferes with the flavor, and the characteristics of the flavor may not be fully exhibited. However, the tobacco composition of this embodiment can fully exhibit the characteristics of the flavor. Because the RI of menthol is 1600 or less, a tobacco composition containing menthol allows the flavor of menthol to be fully enjoyed.

[0033] The tobacco composition can be produced by a known method. For example, it can be produced by mixing the respective components. Alternatively, the respective components can be mixed to form a composition, and the composition can be spread on a substrate to prepare a sheet, which can then be used as the composition itself.

[0034] 4. Non-Combustion Heat-Activated Smoking Articles The tobacco composition is suitable for use in non-combustion heat-activating smoking articles. FIG. 1 shows one embodiment of a non-combustion heat-activating smoking article. As shown in the figure, the non-combustion heat-activating smoking article 20 comprises a tobacco segment 20A, a cylindrical cooling section 20B having perforations on its circumference, and a filter section 20C. The non-combustion heat-activating smoking article 20 may also comprise other components. The axial length of the non-combustion heat-activating smoking article 20 is not limited, but is preferably 40 to 90 mm, more preferably 50 to 75 mm, and even more preferably 50 to 60 mm. The circumferential length of the non-combustion heat-activating smoking article 20 is preferably 16 to 25 mm, more preferably 20 to 24 mm, and even more preferably 21 to 23 mm. For example, the tobacco segment 20A may be 20 mm long, the cooling section 20B may be 20 mm long, and the filter section 20C may be 7 mm long. The lengths of these individual components can be appropriately adjusted depending on manufacturing suitability, required quality, and the like. Although FIG. 1 shows an embodiment in which the first segment 25 is disposed, it is also possible to dispose the first segment 25 and to dispose only the second segment 26 downstream of the cooling section 20B.

[0035] 1) Tobacco Segment 20A The tobacco filler 21 in the tobacco segment 20A contains the component (A) or a tobacco composition containing the same. The method for filling the tobacco filler 21 into the wrapper 22 is not particularly limited; for example, the tobacco filler 21 may be wrapped in the wrapper 22, or the tobacco filler 21 may be filled into a tubular wrapper 22. When the tobacco filler has a longitudinal direction, such as a rectangular shape, it may be filled so that the longitudinal direction is in an unspecified direction within the wrapper 22, or may be aligned in the axial direction of the tobacco segment 20A or in a direction perpendicular to the axial direction. When the tobacco segment 20A is heated, the tobacco components, aerosol source, and water contained in the tobacco filler 21 vaporize and are available for inhalation.

[0036] 2) Cooling Section 20B The cooling section 20B is preferably configured as a tubular member. The tubular member may be, for example, a cardboard tube 23 formed by processing cardboard into a cylindrical shape. The cooling section 20B may also be formed from a sheet of thin material that is wrinkled and then pleated, gathered, or folded to form a channel. Examples of such a material include sheet materials selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polylactic acid, cellulose acetate, and aluminum foil. The total surface area of ​​the cooling section 20B is appropriately adjusted taking cooling efficiency into consideration, but may be, for example, 300 to 1000 mm ２ / mm. The cooling section 20B is preferably provided with perforations 24. The presence of the perforations 24 allows outside air to be introduced into the cooling section 20B during inhalation. As a result, the vaporized aerosol components generated by heating the tobacco segment 20A come into contact with the outside air, their temperature drops, and they liquefy, forming an aerosol. The diameter (distance) of the perforations 24 is not particularly limited, but may be, for example, 0.5 to 1.5 mm. The number of perforations 24 is not particularly limited, and may be one or two or more. For example, a plurality of perforations 24 may be provided around the circumference of the cooling section 20B.

[0037] The cooling portion 20B may be rod-shaped with an axial length of, for example, 7 to 28 mm. For example, the axial length of the cooling portion 20B may be 18 mm. The cooling portion 20B may have a substantially circular axial cross-sectional shape and a diameter of 5 to 10 mm. For example, the diameter of the cooling portion may be approximately 7 mm.

[0038] 3) Filter portion 20C The configuration of the filter portion 20C is not particularly limited, and may be composed of one or more packed layers. The outside of the packed layer may be wrapped with one or more sheets of wrapping paper. The airflow resistance of the filter portion 20C can be appropriately changed depending on the amount, material, etc. of the filter packing filled in the filter portion 20C. For example, when the filter packing is cellulose acetate fiber, the airflow resistance can be increased by increasing the amount of cellulose acetate fiber filled in the filter portion 20C. When the filter packing is cellulose acetate fiber, the packing density of the cellulose acetate fiber is 0.13 to 0.18 g / cm. ３ The airflow resistance is a value measured using an airflow resistance measuring device (product name: SODIMAX, manufactured by SODIM).

[0039] The circumferential length of the filter part 20C is not particularly limited, but is preferably 16 to 25 mm, more preferably 20 to 24 mm, and even more preferably 21 to 23 mm. The length of the filter part 20C in the axial direction (horizontal direction in FIG. 1) can be selected from 4 to 10 mm, and the airflow resistance thereof is selected from 15 to 60 mmH. ２ The axial length of the filter portion 20C is preferably 5 to 9 mm, more preferably 6 to 8 mm. The cross-sectional shape of the filter portion 20C is not particularly limited, but may be, for example, circular, elliptical, polygonal, etc. Furthermore, a destructible capsule containing a fragrance, fragrance beads, or fragrance may be directly added to the filter portion 20C.

[0040] The filter portion 20C may include a center hole portion as the first segment 25. The center hole portion is composed of a first filling layer 25a having one or more hollow portions and an inner plug wrapper (inner wrapping paper) 25b that covers the filling layer. The center hole portion functions to increase the strength of the mouthpiece portion. The center hole portion may not have an inner plug wrapper 25b and its shape may be maintained by thermoforming. The filter portion 20C may include a second segment 26. The second segment 26 is composed of a second filling layer 26a and an inner plug wrapper (inner wrapping paper) 26b that covers the filling layer. The second filling layer 26a may be, for example, a rod with an inner diameter of 5.0 to 1.0 mm, densely packed with cellulose acetate fibers and hardened with 6 to 20 wt.% of a plasticizer containing triacetin added to the cellulose acetate. Due to the high fiber packing density of the second filling layer, during inhalation, air and aerosol flow only through the hollow portions, with almost no flow within the second filling layer. Since the second filling layer inside the center hole portion is a fiber filling layer, the feel from the outside during use is less likely to cause discomfort to the user.

[0041] The first filling layer 25a and the second filling layer 26a are connected by an outer plug wrapper (outer wrapping paper) 27. The outer plug wrapper 27 can be, for example, a cylindrical piece of paper. The tobacco segment 20A, the cooling section 20B, and the connected first filling layer 25a and second filling layer 26a are connected by a mouthpiece lining paper 28. These connections can be made, for example, by applying a vinyl acetate glue or other adhesive to the inner surface of the mouthpiece lining paper 28 and wrapping the three components. These components may also be connected in multiple layers using multiple lining papers.

[0042] A combination of a non-combustion heated smoking article and a heating device for generating aerosol is also referred to as a non-combustion heated smoking system. An example of such a system is shown in Fig. 2. In the figure, the non-combustion heated smoking system includes a non-combustion heated smoking article 20 and a heating device 10 that heats a tobacco segment 20A from the outside.

[0043] The heating device 10 comprises a body 11, a heater 12, a metal tube 13, a battery unit 14, and a control unit 15. The body 11 has a cylindrical recess 16, and the heater 12 and metal tube 13 are disposed at positions corresponding to the tobacco segment 20A to be inserted therein. The heater 12 may be an electric resistance heater, and is heated by power supplied from the battery unit 14 in response to instructions from a temperature-controlling control unit 15. The heat generated by the heater 12 is transferred to the tobacco segment 20A through the metal tube 13, which has high thermal conductivity. While the figure shows a configuration in which the heating device 10 heats the tobacco segment 20A from the outside, it may also heat from the inside. The heating temperature of the heating device 10 is not particularly limited, but is preferably 400°C or less, more preferably 150 to 400°C, and even more preferably 200 to 350°C. The heating temperature refers to the temperature of the heater in the heating device 10. Alternatively, a susceptor may be disposed within the tobacco segment 20A, and the tobacco segment 20A may be heated by an induction heating method.

[0044] Preferred embodiments are described below. Aspect 1: Dry-cured tobacco obtained by drying to present a green color. Aspect 2: L according to CIE 1976 standard. ＊ a ＊ b ＊ a measured according to the method ＊Aspect 3: The cured leaf tobacco according to Aspect 1, wherein the value of the moisture content is -2 or less. Aspect 4: The cured leaf tobacco according to Aspect 1 or 2, wherein the drying step comprises placing the harvested fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll portion is 25% by weight or less. Aspect 5: The cured leaf tobacco according to any one of Aspects 1 to 4, wherein the drying step comprises placing the harvested fresh leaves in an environment of 30 to 40°C and a relative humidity of 60 to 70% for 6 to 12 hours, and then placing the harvested fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll portion is 25% by weight or less. Aspect 6: The cured leaf tobacco according to any one of Aspects 1 to 5, wherein the cured leaf tobacco is a Nicotiana tabacum. Aspect 7: The cured leaf tobacco according to any one of Aspects 1 to 6, wherein the cured leaf tobacco is a Burley variety. Aspect 8: A tobacco composition comprising the cured leaf tobacco according to any one of Aspects 1 to 7, wherein the composition comprises 5 to 90% by weight of the cured leaf tobacco. Aspect 9: The composition according to Aspect 8, further comprising 3 to 30% by weight of an aerosol source. Aspect 10: The composition according to Aspect 9, wherein the aerosol source is selected from the group consisting of glycerin, propylene glycol, 1,3-propanediol, and combinations thereof. Aspect 11: The composition according to any one of Aspects 8 to 10, further comprising 5 to 85% by weight of reconstituted tobacco shreds, or 5 to 85% by weight of tobacco shreds. Aspect 12: The composition according to any one of Aspects 8 to 11, further comprising a non-tobacco flavoring agent. Aspect 13: The composition according to Aspect 12, wherein the non-tobacco flavoring agent is selected from the group consisting of a flavoring, a cooling agent, and a combination thereof. Aspect 14: The composition according to Aspect 13, wherein the flavoring is menthol. Aspect 15: A non-combustion heating smoking article comprising the cured leaf tobacco according to any one of Aspects 1 to 9 or the composition according to any one of Aspects 8 to 14.

[0045] Comparative Example 1 Harvested burley tobacco leaves were hung in a pipe greenhouse covered with a dark curtain and dried in a natural environment for 40 days. The dried tobacco leaves were conditioned in a dark room at 35°C and a relative humidity of 60%, after which the mesophyll and vein portions were separated and the color of the mesophyll was measured. Visual observation revealed that the mesophyll was brown, not green.

[0046] [Example 1] Harvested burley tobacco leaves were dried for 72 hours in an environment at a temperature of 68°C and a relative humidity of 20%. After drying, the leaves were conditioned for 48 hours in an environment at 22°C and a relative humidity of 60%, and then the mesophyll and vein parts were separated and the color of the mesophyll was evaluated. Visual observation revealed that the mesophyll was green. In addition, the L color standardized by CIE 1976 was evaluated. ＊ a ＊ b ＊ The color of the mesophyll was measured according to the method described above. Specifically, the measurement was performed as follows: 1) To obtain the average color value of the entire mesophyll after drying and humidity conditioning, the mesophyll of at least 10 tobacco leaves was crushed and reduced, and a powder sample of 2 mm mesh or less was collected. 2) 5 g of the reduced powder sample was measured using a spectrophotometer (device name: CM3500d, Konica Minolta, Inc.). The powder sample was filled into a transparent glass petri dish to a layer thickness of at least 1 cm, and standard light (D65 light source) was applied from the bottom of the container, and the reflected light was measured using the specular elimination method (SCE). The measurement using the spectrophotometer was performed three times, and the average values ​​are listed in Table 1. The color was evaluated in the following examples and comparative examples using the same method.

[0047] [Example 2] Harvested burley tobacco leaves were dried in an environment at a temperature of 45°C and a relative humidity of 32% until the moisture content of the mesophyll was below 25%. Subsequently, the leaves were dried in an environment at a temperature of 68°C and a relative humidity of 20% until the moisture content of the vein portion was below 12% by weight. After drying, the leaves were conditioned for 48 hours in an environment at a temperature of 22°C and a relative humidity of 60%, and then the mesophyll and vein portions were separated, and the color of the mesophyll was measured. Visual observation revealed that the mesophyll portion was green.

[0048] [Example 3] Harvested burley tobacco leaves were conditioned for 12 hours in an environment at a temperature of 35°C and a relative humidity of 64%, and then conditioned at a temperature of 45°C and a relative humidity of 32% until the moisture content of the mesophyll was below 25% by weight. The leaves were then dried in an environment at 68°C and a relative humidity of 20% until the moisture content of the vein portion was below 12% by weight. After drying, the leaves were conditioned for 48 hours in an environment at 22°C and a relative humidity of 60%, after which the mesophyll and vein portions were separated, and the color of the mesophyll was measured. Visual observation revealed that the mesophyll portion was green.

[0049] [Example 4] Harvested burley tobacco leaves were conditioned for 12 hours in an environment at a temperature of 35°C and a relative humidity of 64%, and then dried in an environment at a temperature of 45°C and a relative humidity of 32% until the moisture content of the mesophyll was below 12% by weight. The dried mesophyll was separated from the midrib, which still contained moisture, and then the color of the mesophyll was measured. Visual observation revealed that the mesophyll was green. The drying process for each example is shown in Figure 4.

[0050]

[0051] [Example A] Sensory evaluation of non-combustion heat-activated smoking articles The dried leaf tobacco obtained in Comparative Example 1 and Examples 1 to 4 was each shredded to a shred width of 0.8 mm. Standard Virginia tobacco shreds were prepared and blended with the shreds obtained in each example at a weight ratio of 50:50. A non-combustion heat-activated smoking article as shown in Figure 1 was prepared. The tobacco segment 20A had a length of 20 mm, the cooling section 20B had a length of 20 mm, and the filter section 20C had a length of 7 mm. Each tobacco segment 20A was filled with 0.3 g of the blended shreds.

[0052] The smoking articles were heated using a heating device and subjected to smoking evaluation by a panel of 10 well-trained experts. The softness during smoking was evaluated on a 5-point scale. The results are shown in the table below. 1 Not particularly soft 2 Not soft 3 Standard 4 Soft 5 Very soft

[0053]

[0054] Compared to Comparative Example 1, the dried leaf tobaccos used in Examples 1 to 4 had lower a* values ​​than the dried leaf tobacco used in Comparative Example 1, and the smoking articles of Examples 1 to 4 were superior in terms of mildness of flavor. Of these, the smoking articles of Examples 2 to 4 were particularly superior in terms of mildness of flavor.

[0055] By drying the harvested tobacco leaves under specific conditions that avoid the browning that inevitably occurs in conventional curing methods, green-colored cured tobacco leaves can be obtained. It is clear that this green-colored cured tobacco leaves can impart a soft aroma when used in non-combustion smoking devices.

[0056] [Example 5] Harvested Virginia tobacco leaves were dried for 72 hours in an environment at a temperature of 68°C and a relative humidity of 20%. After drying, the leaves were conditioned in an environment at 22°C / 60% RH for 48 hours, and then the mesophyll and vein portions were separated.

[0057] [Example B] Comparison of Sugar Content The glucose and fructose contents were measured for the mesophyll of the dried tobacco leaves obtained in Examples 1, 2, 3, and 5. Specifically, the glucose and fructose contents were measured according to the following method.

[0058] Tobacco leaves were crushed to a 1.0 mm mesh or smaller. 1.0 g ± 0.001 g of crushed tobacco leaves was weighed into a glass vial, 40 mL of 50 v / v% acetonitrile solution was added, and the mixture was shaken at 200 rpm for 30 minutes. After shaking, extraction was performed at room temperature for 30 minutes with ultrasonic assistance (Bransonic® cleaner (Branson Ultrasonic Co., Danbury, CT, USA)). The extract was filtered through a 0.2 μm pore size PVDF membrane filter (Whatmann), and the resulting filtrate was subjected to instrumental analysis. A high-performance liquid chromatograph (Agilent 1200 HPLC system) was used. The instrumental analysis conditions were as follows: 1) Detector: A differential refractive index detector (G1362A refractive index detector (Agilent Technology, CA, USA)) was used. The set temperature was 35°C, and the absolute calibration curve method (calibration curve range: 0.1 to 10 g / L) was used. 2) Column: A Carbohydrate Column (250 x 4.6 mm I.D., 4 μm, Waters Co., Milford, MA, USA) was used. 3) Elution conditions: Eluent: acetonitrile (75 v / v%), Flow rate: 1.0 mL / min, Injection volume: 20 μL

[0059]

[0060] In Example 5, Virginia was dried in the same manner as in Example 1 to obtain cured leaf tobacco. This cured leaf tobacco had a higher glucose content than Example 1. When the sugar content is high, the production of sugar-related cooked aromas becomes dominant, causing a cereal smell. From these results, it can be said that Burley is a suitable variety. On the other hand, the cured leaf tobaccos obtained in Examples 2 and 3 have a lower sugar content than the cured leaf tobacco obtained in Example 1. From these results, it can be said that Examples 2 and 3 are more suitable drying methods than Example 1.

Claims

1. Cured tobacco leaves that have been dried to give them a green color.

2. L standardized by CIE 1976 ＊ a ＊ b ＊ a measured according to the method ＊ The cured leaf tobacco of claim 1, wherein the value is −2 or less.

3. Cured tobacco leaf according to claim 1 or 2, wherein the drying step comprises placing the harvested fresh leaves in an environment of 45°C or less until the moisture content of the mesophyll is 25% by weight or less.

4. Cured leaf tobacco according to any one of claims 1 to 3, wherein the drying step comprises a step of storing the harvested fresh leaves in an environment of 30-40°C and a relative humidity of 60-70% for 6-12 hours, and then storing them in an environment of 45°C or less until the moisture content of the mesophyll is reduced to 25% by weight or less.

5. A dried leaf tobacco according to any one of claims 1 to 4, which is produced by removing only the mesophyll portion when the moisture content of the mesophyll portion reaches 12% by weight or less during the drying process.

6. The cured leaf tobacco according to any one of claims 1 to 5, which is Nicotiana tabacum.

7. The cured leaf tobacco according to any one of claims 1 to 6, which is a burley variety.

8. A tobacco composition comprising the dried leaf tobacco according to any one of claims 1 to 7, wherein the composition contains 5 to 90% by weight of the dried leaf tobacco.

9. The composition of claim 8, further comprising 3 to 30% by weight of an aerosol source.

10. The composition of claim 9, wherein the aerosol source is selected from the group consisting of glycerin, propylene glycol, 1,3-propanediol, and combinations thereof.

11. The composition of any one of claims 8 to 10, further comprising 5 to 85% by weight of reconstituted tobacco shreds, or 5 to 85% by weight of tobacco shreds.

12. The composition of any one of claims 8 to 11, further comprising a non-tobacco flavoring agent.

13. The composition of claim 12, wherein the non-tobacco flavoring agent is selected from the group consisting of flavors, cooling agents, and combinations thereof.

14. The composition of claim 13, wherein the flavoring agent is menthol.

15. A non-combustion heating type smoking article comprising the dried tobacco leaf according to any one of claims 1 to 9 or the composition according to any one of claims 8 to 14.

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