Method for treating tobacco raw material, tobacco raw material, non-combustion heating type flavor inhaler, and non-combustion heating type flavor inhalation system

Abstract

The present invention provides a method for treating a tobacco raw material, which enables a reduction in the amount of furan analogs contained in smoke which is generated when the tobacco raw material is heated. A method for treating a tobacco raw material, the method comprising: a step of preparing a tobacco raw material having a pH of 8 or greater by adding a basic substance to a tobacco raw material; and a step of heating the tobacco raw material having a pH of 8 or greater until the pH reaches 6.3 or less.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for treating a tobacco raw material, a tobacco raw material, a heat-not-burn flavor inhaler, and a heat-not-burn flavor inhalation system.BACKGROUND ART

[0002] A flavor is obtained from a combusted flavor inhaler (cigarette) by burning a tobacco filling material containing leaf tobacco. Meanwhile, heat-not-burn flavor inhalers, with which a flavor is obtained by heating rather than burning a tobacco raw material, have been proposed as an alternative to these combusted flavor inhalers. The tobacco raw material contains sugars which are decomposed when the tobacco raw material is heated, and are detected as furan analogs in smoke. Furan analogs have a characteristic sweet aroma and it may therefore be desirable to reduce this aroma, depending on the type of heat-not-burn flavor inhaler. Meanwhile, the methods disclosed in PTL 1-5, for example, may be cited as methods for treating tobacco raw materials.CITATION LISTPATENT LITERATURE

[0003] PTL 1: JP 2016-506744 A PTL 2: JP 2016-527913 A PTL 3: WO 2013 / 146952 A1 PTL 4: WO 2016 / 063775 A1 PTL 5: JP H01-231884 A SUMMARY OF INVENTIONTECHNICAL PROBLEM

[0004] The objective of the present invention lies in providing a method for treating a tobacco raw material, which enables a reduction in the amount of furan analogs contained in smoke which is generated when the tobacco raw material is heated, and also in providing a tobacco raw material obtained by this method, and a heat-not-burn flavor inhaler and a heat-not-burn flavor inhalation system containing this tobacco raw material.SOLUTION TO PROBLEM

[0005] The present invention includes the following embodiments. [1] A method for treating a tobacco raw material, the method comprising: a step of preparing a tobacco raw material having a pH of 8 or greater by adding a basic substance to a tobacco raw material; and a step of heating the tobacco raw material having a pH of 8 or greater until the pH reaches 6.3 or less. [2] The method as disclosed in [1], wherein the heating is performed in a closed space. [3] The method as disclosed in [1] or [2], wherein the heating is performed under pressurization. [4] The method as disclosed in any of [1] to [3], wherein a heating temperature in the heating is 100-200°C. [5] The method as disclosed in any of [1] to [4], wherein a heating time in the heating is 30 minutes-4 hours. [6] The method as disclosed in any of [1] to [5], wherein the tobacco raw material is of the flue-cured variety. [7] The method as disclosed in any of [1] to [6], wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the tobacco raw material after the treatment is 40 mg or less, and an amount of nicotine contained in 1 g of the tobacco raw material after the treatment is 10 mg or greater. [8] The method as disclosed in any of [1] to [7], wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less. [9] A tobacco raw material treated by the method as disclosed in any of [1] to [8].

[10] A flue-cured tobacco raw material wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the flue-cured tobacco raw material is 40 mg or less, and an amount of nicotine contained in 1 g of the flue-cured tobacco raw material is 10 mg or greater.

[11] The flue-cured tobacco raw material as disclosed in

[10] , wherein an amount of malic acid contained in 1 g of the flue-cured tobacco raw material is 30 mg or greater.

[12] A flue-cured tobacco raw material wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less.

[13] A heat-not-burn flavor inhaler containing the tobacco raw material as disclosed in any of [9] to

[12] .

[14] A heat-not-burn flavor inhalation system comprising: the heat-not-burn flavor inhaler as disclosed in

[13] ; and a heating device for heating the tobacco raw material in the heat-not-burn flavor inhaler. ADVANTAGEOUS EFFECTS OF INVENTION

[0006] The present invention makes it possible to provide a method for treating a tobacco raw material, which enables a reduction in the amount of furan analogs contained in smoke which is generated when the tobacco raw material is heated, and also to provide a tobacco raw material obtained by this method, and a heat-not-burn flavor inhaler and a heat-not-burn flavor inhalation system containing this tobacco raw material.BRIEF DESCRIPTION OF DRAWINGS

[0007] Fig. 1 is a view in cross section showing an example of a heat-not-burn flavor inhaler according to the embodiment. Fig. 2 is a view in cross section showing an example of a heat-not-burn flavor inhalation system according to the embodiment, where (a) shows a state before the heat-not-burn flavor inhaler is inserted into a heating device, and (b) shows a state where the heat-not-burn flavor inhaler has been inserted into the heating device to be heated. DESCRIPTION OF EMBODIMENTSMethod for treating tobacco raw material

[0008] A method for treating a tobacco raw material according to the embodiment comprises the following steps: a step of preparing a tobacco raw material having a pH of 8 or greater by adding a basic substance to a tobacco raw material (this step will also be referred to below as a "basic substance addition step"); and a step of heating the tobacco raw material having a pH of 8 or greater until the pH reaches 6.3 or less (this step will also be referred to below as a "heating step").

[0009] Furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural may be cited as the main furan analogs contained in smoke generated when the tobacco raw material is heated. These furan analogs are not originally contained in the tobacco raw material, or are only contained in trace amounts if present. Most of the furan analogs contained in the smoke generated when the tobacco raw material is heated are assumed to be formed by pyrolysis of sugars (mainly the three sugars glucose, fructose and sucrose) contained in the tobacco raw material. A reduction in the amount of furan analogs contained in the smoke generated when the tobacco raw material is heated would therefore be feasible if the content of sugars (especially the three sugars above) contained in the tobacco raw material could be reduced.

[0010] In the method for treating a tobacco raw material according to this embodiment, a tobacco raw material having a pH of 8 or greater is first of all prepared by adding a basic substance to the tobacco raw material. A normal tobacco raw material pH is around 4.0-6.0. Adding a basic substance to give the tobacco raw material a pH of 8 or greater allows a sugar decomposition reaction to progress more easily during heat treatment. The tobacco raw material having a pH of 8 or greater is then heated until the pH reaches 6.3 or less. The pH of the tobacco raw material having a pH of 8 or greater falls as it is heated. This is because, as decomposition of the sugars in the tobacco raw material progresses, acidic substances such as formic acid and acetic acid are formed as decomposition products. That is to say, using the pH of the tobacco raw material as an indicator, it is possible to judge the extent to which the sugars have decomposed (and thus the extent to which it is possible to reduce furan analogs contained in the smoke generated when the treated tobacco raw material is heated). In the method according to this embodiment, the sugars are sufficiently decomposed by setting the pH of the heated tobacco raw material at 6.3 or less so that the furan analogs contained in the smoke generated when the treated tobacco raw material is heated can be sufficiently reduced.

[0011] It should be noted that the amount of flavor components generated when the tobacco raw material is heated varies according to the pH of the tobacco raw material. However, the pH of the treated tobacco raw material obtained by the method according to this embodiment is 6.3 or less, which is comparable with the pH of an untreated tobacco raw material (approximately 4.0-6.0), so the method according to this embodiment makes it possible to reduce the amount of furan analogs generated during heating while also keeping the amount of useful flavor components, other than furan analogs, comparable with the amount in an untreated tobacco raw material.Basic substance addition step

[0012] In this step, a tobacco raw material having a pH of 8 or greater is prepared by adding a basic substance to the tobacco raw material. Whole tobacco or parts of tobacco may be used as tobacco raw material to be treated, and parts of tobacco that may be cited include leaves, veins, stems, roots, flowers, and mixtures thereof. Examples are varieties of tobacco raw material that may be cited include flue-cured, Burley, Oriental or native type, etc. These may be used alone or in combinations of two or more.

[0013] Among these, a tobacco raw material of the flue-cured variety is preferably used in the method according to this embodiment. Burley may be cited as a tobacco raw material variety having a low sugar content to start with. However, useful flavor precursor substances (e.g., 3-oxo-alpha-ionol, solavetivone, malic acid, proline, and palmitic acid, etc.) other than sugars are contained in large amounts in flue-cured tobacco but are scarce in Burley tobacco. The treatment method according to this embodiment allows only the sugar content to be selectively reduced, especially when the tobacco raw material is heated in a closed space, which therefore makes it possible to obtain a tobacco raw material having a low sugar content but having a high content of other useful flavor precursor substances when a tobacco raw material of the flue-cured variety is used.

[0014] The tobacco raw material which is used may be in the state of raw leaves immediately after harvesting which have not been dried, etc., or may be a material which has been dried and aged after harvesting, or a combination thereof may be used. Furthermore, midrib tobacco or expanded tobacco, etc. obtained by treating the above tobacco raw materials may also be used. It is also possible to use a tobacco sheet (reconstituted tobacco) produced by using a tobacco extract obtained from these tobacco raw materials. These tobaccos may be used alone, or multiple tobaccos may be used in combination.

[0015] Examples of basic substances added to the tobacco raw material that may be cited include: sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium hydroxide, and potassium hydroxide, etc. These may be used alone or in combinations of two or more. There is no particular limitation as to the method of adding the basic substance, but methods that may be cited include a method of spraying the tobacco raw material with a solution obtained by dissolving the basic substance in a solvent such as water, and a method of directly adding the basic substance to a tobacco slurry or a tobacco water extract prepared in the process of manufacturing reconstituted tobacco.

[0016] In this step, the pH of the tobacco raw material is set at 8 or greater, but the pH of the tobacco raw material is preferably set at 8.1 or greater, and more preferably at 8.2 or greater. The upper limit for the pH range of the tobacco raw material is preferably 9.0 or less, and more preferably 8.5 or less, from the perspective of restricting the amount of volatilization of desirable flavor components which volatilize when a basic tobacco is formed. Note that the pH of the tobacco raw material is measured by the following method. 0.5 g (W.B.) of tobacco raw material is introduced into a screw vial having a capacity of 20 mL, and 5 mL of ultrapure water (tradename: Milli-Q) is added. The materials are shaken for 30 minutes at 200 rpm. The pH of the contents of the screw vial is measured using a pH meter (tradename: 0040-10D pH measurement electrode, F-72 meter, manufactured by HORIBA, Ltd.).Heating step

[0017] In this step, the tobacco raw material having a pH of 8 or greater obtained in the basic substance addiction step is heated until the pH reaches 6.3 or less. The heating is preferably performed in a closed space (i.e., inside a hermetically sealed space). Heating inside a hermetically sealed autoclave, for example, may be cited as heating in a closed space. Heating in a closed space enables a greater reduction in the amount of furan analogs than when heating is performed in an open space, and also makes it possible to sufficiently maintain the content of nicotine and other useful flavor precursor substances contained in the tobacco raw material. The heating is especially preferably performed under pressurization. The pressure in the pressurization may be 0.05-0.3 MPa (gauge pressure), for example.

[0018] The heating temperature in the heating is preferably 100-200°C. A heating temperature of 100°C or greater allows the sugar decomposition reaction to progress better, and the pH also decreases sufficiently. Furthermore, a heating temperature of 200°C or less makes it possible to inhibit the generation of fishy, burnt and other unpleasant odors. The heating temperature in the heating is more preferably 100-150°C, and even more preferably 100-130°C.

[0019] The heating time in the heating depends on the heating temperature, but is preferably 30 minutes-4 hours. A heating time of 30 minutes or greater allows the sugar decomposition reaction to progress better, and the pH also decreases sufficiently. Furthermore, a heating time of 4 hours or less makes it possible to inhibit an excessive reduction in pH and also to prevent variations in the amount of components formed when the tobacco raw material is heated. The heating time in the heating is more preferably 1-4 hours, and even more preferably 2-4 hours. Note that the heating time indicates the time of heating after a set temperature has been reached, and does not include the time taken for the temperature to rise or fall.

[0020] In this step, the pH of the heated tobacco raw material is 6.3 or less, but it is preferably 6 or less, and more preferably 5.5 or less. The lower limit for the pH range of the heated tobacco raw material is preferably 4.0 or greater, and more preferably 4.5 or greater, from the perspective of making it possible to prevent variations in the amount of components formed when the tobacco raw material is heated. Note that the pH of the tobacco raw material is measured by means of the method described above.

[0021] The heated tobacco raw material may be dried and may be conditioned under a predetermined temperature and humidity environment.Characteristics of treated tobacco raw material

[0022] The amount of sugars (three sugars) consisting of glucose, fructose and sucrose contained in 1 g of the treated tobacco raw material, which has been treated by means of the method according to this embodiment, is preferably 40 mg or less. A content of the three sugars of 40 mg or less makes it possible to sufficiently reduce the amount of furan analogs contained in the smoke generated when the tobacco raw material is heated. The amount of the three sugars contained in 1 g of the treated tobacco raw material is more preferably 30 mg or less, even more preferably 25 mg or less, and especially preferably 20 mg or less. There is no particular limitation as to the lower limit of the range of the amount of the three sugars contained in 1 g of the treated tobacco raw material, but this lower limit may be 5 mg or greater, for example. Note that the amount of the three sugars contained in the treated tobacco raw material can be measured by means of the following method. The amount of the three sugars can be measured by subjecting an extract, which is obtained by extracting 1 g of the treated tobacco raw material with ultrapure water, to high-performance liquid chromatography.

[0023] The amount of nicotine contained in 1 g of the treated tobacco raw material, which has been treated by means of the method according to this embodiment, is preferably 10 mg or greater. A nicotine content of 10 mg or greater makes it possible to obtain sufficient flavor during heating. The amount of nicotine contained in 1 g of the treated tobacco raw material is more preferably 12 mg or greater, and even more preferably 15 mg or greater. There is no particular limitation as to the upper limit of the range of the amount of nicotine contained in 1 g of the treated tobacco raw material, but this upper limit may be 30 mg or less, for example. Note that the amount of nicotine contained in the treated tobacco raw material can be measured by means of the following method. The amount of nicotine can be measured by subjecting an extract, which is obtained by addition of 1 mol / L sodium hydroxide to 1 g of the treated tobacco raw material followed by extraction with hexane, to gas chromatography.

[0024] The amount of sugars (the three sugars) consisting of glucose, fructose and sucrose contained in 1 g of the treated tobacco raw material is preferably 40 mg or less, and the amount of nicotine contained in 1 g of the treated tobacco raw material is preferably 10 mg or greater, in order to be able to maintain the amount of nicotine supplied while also reducing the amount of furan analogs generated during heating.

[0025] The total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural (also referred to below as the "eight furan analogs") in the smoke generated when 0.2 g of the treated tobacco raw material, which has been treated by means of the method according to this embodiment, is heated for 5 minutes at 300°C, is preferably 410 µg or less. The total mass of the eight furan analogs being 410 µg or less makes it possible to sufficiently reduce the characteristic sweet aroma originating from furan analogs. The total mass of the eight furan analogs in the smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C is more preferably 400 µg or less, even more preferably 350 µg or less, and especially preferably 300 µg or less. There is no particular limitation as to the lower limit of the range of the total mass of the eight furan analogs in the smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C, but this lower limit may be 50 µg or greater, for example.

[0026] Note that the total mass of the eight furan analogs in the smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C is measured by means of the following method. 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C under a nitrogen atmosphere inside an infrared gold image furnace. The smoke generated in this process is trapped by a Cambridge filter and -70°C methanol, and the total amount of the eight furan analogs is measured by gas chromatography.Flue-cured tobacco raw materialFirst Embodiment

[0027] In the flue-cured tobacco raw material according to this embodiment, the amount of sugars (the three sugars) consisting of glucose, fructose and sucrose contained in 1 g of the flue-cured tobacco raw material is 40 mg or less, and the amount of nicotine contained in 1 g of the flue-cured tobacco raw material is 10 mg or greater. 1 g of normal flue-cured tobacco raw material usually contains in excess of 50 mg of these three sugars. However, in the flue-cured tobacco raw material according to this embodiment, the amount of the three sugars contained in 1 g of the flue-cured tobacco raw material is 40 mg or less, so it is possible to reduce the amount of furan analogs contained in the smoke generated when the tobacco raw material is heated, and thereby reduce the characteristic sweet aroma originating from the furan analogs. Meanwhile, the amount of nicotine contained in 1 g of the flue-cured tobacco raw material is 10 mg or greater, so a sufficient flavor can be obtained during heating. The flue-cured tobacco raw material according to this embodiment can be suitably produced by treating a flue-cured tobacco raw material with the method for treating a tobacco raw material according to the embodiment.

[0028] The amount of the three sugars contained in 1 g of the flue-cured tobacco raw material is preferably 30 mg or less, more preferably 25 mg or less, and even more preferably 20 mg or less. There is no particular limitation as to the lower limit of the range of the amount of the three sugars contained in 1 g of the flue-cured tobacco raw material, but this lower limit may be 5 mg or greater, for example. The amount of the three sugars contained in 1 g of the flue-cured tobacco raw material can be measured by the same method as that described above for measuring the amount of the three sugars contained in the treated tobacco raw material.

[0029] The amount of nicotine contained in 1 g of the flue-cured tobacco raw material is preferably 12 mg or greater, and more preferably 15 mg or greater. There is no particular limitation as to the upper limit of the range of the amount of nicotine contained in 1 g of the flue-cured tobacco raw material, but this upper limit may be 30 mg or less, for example. The amount of nicotine contained in 1 g of the flue-cured tobacco raw material can be measured by the same method as that described above for measuring the amount of nicotine contained in the treated tobacco raw material.

[0030] The amount of malic acid contained in 1 g of the flue-cured tobacco raw material is preferably 30 mg or greater. Malic acid is a useful flavor precursor substance which improves the quality of the flavor when it is contained an amount of 30 mg or greater in 1 g of the flue-cured tobacco raw material. The amount of malic acid contained in 1 g of the flue-cured tobacco raw material is more preferably 31 mg or greater, and even more preferably 32 mg or greater. There is no particular limitation as to the upper limit of the range of the amount of malic acid contained in 1 g of the flue-cured tobacco raw material, but this upper limit may be 40 mg or less, for example. The amount of malic acid contained in 1 g of the flue-cured tobacco raw material can be measured by means of the following method. The amount of malic acid can be measured by supplying an extract, which is obtained by extracting 1 g of the flue-cured tobacco raw material with ultrapure water, to a capillary electrophoresis system.Second Embodiment

[0031] In the flue-cured tobacco raw material according to this embodiment, the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural (the eight furan analogs) in the smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less. The total mass of the eight furan analogs in smoke generated when 0.2 g of normal flue-cured tobacco raw material is heated for 5 minutes at 300°C is usually in excess of 1000 µg. However, in the flue-cured tobacco raw material according to this embodiment, the total mass of the eight furan analogs in the smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C is 410 µg or less, so there is little of the characteristic sweet aroma originating from the furan analogs generated during heating. The flue-cured tobacco raw material according to this embodiment can be suitably produced by treating a flue-cured tobacco raw material with the method for treating a tobacco raw material according to the embodiment.

[0032] The total mass of the eight furan analogs in the smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C is preferably 400 µg or less, more preferably 350 µg or less, and even more preferably 300 µg or less. There is no particular limitation as to the lower limit of the range of the total mass of the eight furan analogs in the smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C, but this lower limit may be 50 mg or greater, for example. The total mass of the eight furan analogs in the smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C can be measured by the same method as that described above for measuring the total mass of the eight furan analogs in the smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C.Heat-not-burn flavor inhaler

[0033] The heat-not-burn flavor inhaler according to this embodiment contains the tobacco raw material according to the embodiment. The heat-not-burn flavor inhaler according to this embodiment contains the tobacco raw material according to the embodiment, so there is little of the characteristic sweet aroma originating from the furan analogs generated during use (during heating).

[0034] Fig. 1 shows an example of a heat-not-burn flavor inhaler according to the embodiment. The heat-not-burn flavor inhaler 1 shown in fig. 1 comprises: a tobacco-containing segment 2 filled with the tobacco raw material according to the embodiment; a cylindrical cooling segment 3 having a circumferential perforation 8; a center hole segment 4; and a filter segment 5. The heat-not-burn flavor inhaler according to the embodiment may have other segments in addition to the tobacco-containing segment, the cooling segment, the center hole segment, and the filter segment.

[0035] There is no particular limitation as to the axial length of the heat-not-burn flavor inhaler according to the embodiment, but it is preferably 40 mm-90 mm, more preferably 50 mm-75 mm, and even more preferably 50 mm-60 mm. Furthermore, the circumferential length of the heat-not-burn flavor inhaler is preferably 16 mm-25 mm, more preferably 20 mm-24 mm, and even more preferably 21 mm-23 mm. In an exemplary aspect which may be cited, the length of the tobacco-containing segment is 20 mm, the length of the cooling segment is 20 mm, the length of the center hole segment is 8 mm, and the length of the filter segment is 7 mm. Note that the length of the filter segment may be selected from a range of between 4 mm and 10 mm. Furthermore, the length can be selected so that the ventilation resistance of the filter segment here is between 15 mmH 2 O per segment and 60 mmH 2 O per segment. The lengths of these individual segments can be modified, as appropriate, depending on manufacturability and required quality, for example. The function as a heat-not-burn flavor inhaler can still be achieved if the filter segment is disposed downstream of the cooling segment without the use of a center hole segment.Tobacco-containing segment

[0036] The tobacco-containing segment 2 comprises a wrapping paper (also referred to below as a "wrapper") packed with the tobacco raw material according to the embodiment. There is no particular limitation as to the method for packing the wrapping paper with the tobacco raw material, but the tobacco raw material may be enclosed in the wrapper, or a cylindrical wrapper may be packed with the tobacco raw material. When the tobacco raw material has a longitudinal shape such as a rectangular shape, the tobacco raw material may be packed inside the wrapper so that the longitudinal direction thereof is randomly oriented, or may be packed so that the longitudinal direction is oriented in the axial direction of the tobacco-containing segment 2 or in a direction perpendicular thereto.Cooling segment

[0037] As shown in fig. 1, the cooling segment 3 may be formed by a cylindrical member 7. The cylindrical member 7 may be a paper tube obtained by processing cardboard into a cylindrical shape, for example.

[0038] The cylindrical member 7 and a mouthpiece lining paper 12 which will be described later are provided with the perforation 8 which penetrates both. The perforation 8 allows external air to be introduced into the cooling segment 3 during drawing. As a result, the aerosol vaporized component generated by heating of the tobacco-containing segment 2 is liquefied because it comes into contact with the external air so that the temperature thereof decreases, and an aerosol is formed. There is no particular limitation as to the diameter of (length across) the perforation 8, but it may be 0.5 mm-1.5 mm, for example. There is no particular limitation as to the number of perforations 8 and there may be one, or two or more. Multiple perforations 8 may be provided on the circumference of the cooling segment 3, for example.

[0039] The amount of external air introduced from the perforation 8 is preferably 85 vol% or less, and more preferably 80 vol% or less, with respect to the overall volume of gas drawn in by the user. A proportion of up to 85 vol% of external air will make it possible to adequately restrict the reduction in flavor resulting from dilution with external air. Note that this is also referred to as the ventilation ratio. The lower limit of the ventilation ratio range is preferably 55 vol% or greater, and more preferably 60 vol% or greater, from the perspective of cooling.

[0040] Furthermore, the cooling segment may also be a segment comprising a sheet of a suitable constituent material which has been creased, pleated, gathered, or folded. The cross-sectional profiles of such elements may exhibit randomly oriented channels. Furthermore, the cooling segment may comprise a bundle of longitudinally-extending tubes. Such a cooling segment may be formed, for example, by wrapping a pleated, gathered, or folded sheet material with the wrapping paper.

[0041] The axial length of the cooling segment may be 7 mm-28 mm, and may be 18 mm, for example. Furthermore, the cooling segment may be substantially circular in terms of the axial cross-sectional shape thereof, with the diameter being 5 mm-10 mm, for example, and may be approximately 7 mm, for example.Center hole segment

[0042] The center hole segment is formed by a filling layer having one or more hollow portions, and an inner plug wrapper (inside wrapping paper) covering the filling layer. As shown in fig. 1, for example, the center hole segment 4 is formed by a first filling layer 9 having a hollow portion, and a first inner plug wrapper 10 covering the first filling layer 9. The center hole segment 4 has the function of increasing the strength of the mouthpiece segment 6. The first filling layer 9 may be formed, for example, as a rod having an inner diameter of φ1.0 mm-φ5.0 mm packed with a high density of cellulose acetate fibers, a plasticizer comprising triacetin being added thereto in an amount of 6 mass%-20 mass%, in relation to the mass of cellulose acetate, and the plasticizer being cured. The first filling layer 9 has a high packing density of fibers, so the air and aerosol flow only through the hollow portion during drawing, with virtually none flowing through the first filling layer 9. The first filling layer 9 inside the center hole segment 4 is a fiber filled layer, and the user will therefore have little sense of incongruity when touching the outside during use. Moreover, the shape of the center hole segment 4 may also be retained by means of thermoforming, without the first inner plug wrapper 10 being provided.Filter segment

[0043] There is no particular limitation as to the configuration of the filter segment 5, but it may be formed from a single filling layer or multiple filling layers. The outer side of the filling layer may be wrapped with a single or multiple wrapping papers. The airflow resistance per segment of the filter segment 5 may be suitably altered by the amount and material, etc. of the filling material filling the filter segment 5. For example, when the filling material is cellulose acetate fibers, the airflow resistance may be increased by increasing the amount of cellulose acetate fibers filling the filter segment 5. When the filling material is cellulose acetate fibers, the packing density of cellulose acetate fibers may be 0.13-0.18 g / cm 3< . Note that the airflow resistance is a value measured by means of an airflow resistance meter (tradename: SODIMAX, manufactured by SODIM).

[0044] There is no particular limitation as to the circumferential length of the filter segment 5, but it is preferably 16-25 mm, more preferably 20-24 mm, and even more preferably 21-23 mm. An axial length of 4-10 mm may be selected for the filter segment 5, and the axial length is selected so that the airflow resistance is 15-60 mmH 2 O per segment, for example. The axial length of the filter segment 5 is preferably 5-9 mm, and more preferably 6-8 mm. There is no particular limitation as to the cross-sectional shape of the filter segment 5, but it may be circular, elliptical, or polygonal, etc., for example. Furthermore, a breakable capsule containing a flavoring material, flavor beads, or a flavoring material may be directly added to the filter segment 5.

[0045] As shown in fig. 1, the center hole segment 4 and the filter segment 5 may be connected by an outer plug wrapper (outside wrapping paper) 11. The outer plug wrapper 11 may be paper in a cylindrical shape, for example. Furthermore, the tobacco-containing segment 2, the cooling segment 3, and the connected center hole segment 4 and filter segment 5 may be connected by means of the mouthpiece lining paper 12. These connections may be formed, for example, by coating an inside surface of the mouthpiece lining paper 12 with a glue such as a vinyl acetate-based glue, inserting the abovementioned three segments therein, and wrapping the segments with the mouthpiece lining paper. It should be noted that these segments may also be connected by multiple separate connections with multiple lining papers.Heat-not-burn flavor inhalation system

[0046] The heat-not-burn flavor inhalation system according to the embodiment comprises: the heat-not-burn flavor inhaler according to the embodiment, and a heating device for heating the tobacco raw material in the heat-not-burn flavor inhaler. The heat-not-burn flavor inhalation system according to this embodiment comprises the heat-not-burn flavor inhaler according to the embodiment, so there is little of the characteristic sweet aroma originating from the furan analogs generated during use (during heating). The heat-not-burn flavor inhalation system according to the embodiment may have components other than the heat-not-burn flavor inhaler according to the embodiment and the heating device.

[0047] Fig. 2 shows an example of the heat-not-burn flavor inhalation system according to the embodiment. The heat-not-burn flavor inhalation system shown in fig. 2 comprises: the heat-not-burn flavor inhaler 1 according to the embodiment; and a heating device 13 for heating the tobacco-containing segment of the heat-not-burn flavor inhaler 1 from the outside.

[0048] Fig. 2(a) shows a state before the heat-not-burn flavor inhaler 1 is inserted into the heating device 13, and fig. 2(b) shows a state where the heat-not-burn flavor inhaler 1 has been inserted into the heating device 13 to be heated. The heating device 13 shown in fig. 2 comprises: a body 14, a heater 15, a metal tube 16, a battery unit 17, and a control unit 18. The body 14 comprises a cylindrical recess 19, and the heater 15 and metal tube 16 are disposed on an inside side face of the recess 19 at positions corresponding to the tobacco-containing segment of the heat-not-burn flavor inhaler 1 which is inserted into the recess 19. The heater 15 may be a heater employing electrical resistance, with electrical power being supplied by the battery unit 17 in accordance with a command from the control unit 18 which controls the temperature, such that heating is effected by the heater 15. The heat emitted from the heater 15 is transferred to the tobacco-containing segment of the heat-not-burn flavor inhaler 1 through the metal tube 16 which has high thermal conductivity.

[0049] As Fig. 2(b) is a schematic diagram, there is a gap between the outer circumference of the heat-not-burn flavor inhaler 1 and the inner circumference of the metal tube 16, but for the purposes of efficient heat transfer, it is actually preferable for there to be no gap between the outer circumference of the heat-not-burn flavor inhaler 1 and the inner circumference of the metal tube 16. Note also that the heating device 13 heats the tobacco-containing segment of the heat-not-burn flavor inhaler 1 from the outside, but the tobacco-containing segment may also be heated from the inside.

[0050] There is no particular limitation as to the temperature of heating produced by the heating device, but it is preferably 400°C or less, more preferably 150°C-400°C, and even more preferably 200°C-350°C. Note that the heating temperature indicates the temperature of the heater of the heating device.EXAMPLES

[0051] The embodiments will be described in detail below through examples, but the embodiments are not limited to those examples. Note that the following methods are used to measure the amount of furan analogs in smoke and to measure the amounts of the three sugars, nicotine, and malic acid.Measurement of amount of furan analogs in smoke

[0052] The total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural (the eight furan analogs) in the smoke generated when 0.2 g of the tobacco raw material obtained after treatment was heated for 5 minutes at 300°C, was measured by means of the following method. 0.2 g of the treated tobacco raw material was heated for 5 minutes at 300°C under a nitrogen atmosphere inside an infrared gold image furnace. The smoke generated in this process was trapped by a Cambridge filter and -70°C methanol, and the total amount of the eight furan analogs was measured by gas chromatography.

[0053] Measurement of amounts of the three sugars, nicotine, and malic acid The amount of the sugars (three sugars) consisting of glucose, fructose and sucrose contained in 1 g of the resulting treated tobacco raw material was measured by means of the following method. The amount of the three sugars was measured by subjecting an extract, which was obtained by extracting 1 g of the treated tobacco raw material with ultrapure water, to high-performance liquid chromatography. Furthermore, the amount of nicotine contained in 1 g of the resulting treated tobacco raw material was measured by means of the following method. The amount of nicotine was measured by subjecting an extract, which was obtained by addition of 1 mol / L sodium hydroxide to 1 g of the treated tobacco raw material followed by extraction with hexane, to gas chromatography. Furthermore, the amount of malic acid contained in 1 g of the resulting treated tobacco raw material was measured by means of the following method. The amount of malic acid was measured by supplying an extract, which was obtained by extracting 1 g of the treated tobacco raw material with ultrapure water, to a capillary electrophoresis system.EXAMPLE 1

[0054] A blend of tobacco sheet and cut lamina, produced using flue-cured tobacco as a raw material, was prepared as a tobacco raw material. 6 g of a 10 wt% sodium carbonate aqueous solution (3 wt% as sodium carbonate) were spray-added using a glass atomizer to 20 g (W.B.) of this tobacco raw material. The pH of the resulting tobacco raw material was 8.03. The tobacco raw material was then introduced into a glass Erlenmeyer flask, covered with an aluminum foil lid, and placed in an autoclave (tradename: LSX-500, manufactured by Tomy Seiko Co., Ltd.). Heating and pressurization were started with the autoclave set to maintain a maximum temperature of 120°C for 30 minutes. The pressure inside the autoclave was 0.1 MPa during heating. After the end of heating, the tobacco raw material was removed and the pH was measured. The pH of this tobacco raw material was 6.13. The tobacco raw material was then moved to a tray and air-dried for 30 minutes in a draft. The dried material was then conditioned for at least 48 hours under conditions of room temperature 22°C and humidity 60%. The total mass of the eight furan analogs in the smoke generated when 0.2 g of the resulting treated tobacco raw material was heated for 5 minutes at 300°C was measured by means of the method described above. Furthermore, the amount of the three sugars contained in 1 g of the resulting treated tobacco raw material was measured by means of the method described above. The results are shown in Table 1.EXAMPLES 2-5

[0055] Tobacco raw materials were treated in the same way as in Example 1, except that the heating time was changed between 1 and 4 hours, and measurements were taken. The results are shown in Table 1. Note that the pressure inside the autoclave during heating was 0.1 MPa in all cases. Furthermore, the amounts of the three sugars and malic acid were measured by means of the methods described above for Examples 3-5, and the amount of nicotine was also measured by means of the method described above for Example 3.COMPARATIVE EXAMPLES 1-13

[0056] Tobacco raw materials were treated in the same way as in Example 1, except that the amount of basic substance added, heating yes / no, the heating method, the heating temperature, and the heating time were changed as in Table 1, and measurements were taken. The results are shown in Table 1. Note that Comparative Example 1 shows an untreated tobacco raw material. Furthermore, "AC" in the "Heating" column of Table 1 indicates autoclave heating in a closed space (pressurized environment), and "Oven" indicates oven heating in an open system. The same also applies to Tables 2 and 3. Table 1Amo unt of basic subst ance adde d (wt% )Hea tingHeatin g temper ature (°C)Heat ing timepH before basic substan ce addedpH after basic subst ance adde dpH after heati ngAmo unt of fura n anal ogs in smo ke (µg)Cont ent of three suga rs (mg)Nico tine cont ent (mg)Mali c acid cont ent (mg)Ex. 13.00Yes AC1200.5h5.268.036.13406. 139.0 7Ex. 23.00Yes AC1201h5.268.306.10356. 8Ex. 33.00Yes AC1202h5.268.305.86298. 828.8 116.7 230.5 5Ex. 43.00Yes AC1203h5.268.305.38244. 320.4 830.0 9Ex. 53.00Yes AC1204h5.268.305.30220. 418.7 031.2 9Comp. Ex. 10No--5.26--1085 .169.9 017.2 632.2 5Com p. Ex. 20Yes AC1201h5.26-4.901082 .1Com p. Ex. 30Yes AC1202h5.26-4.76806. 4Com p. Ex. 43.00No--5.268.30-770. 1Com p. Ex. 53.00Yes AC902h5.268.306.63512. 552.5 0Com p. Ex. 63.00Yes AC702h5.268.307.51468. 860.7 2Com p. Ex. 71.50No--5.267.08-726. 0Com p. Ex. 81.50Yes AC1202h5.267.085.21553. 3Com p. Ex. 93.00Yes Ove n1202h5.268.307.34513. 44.20Com p. Ex. 103.00Yes Ove n902h5.268.307.56629. 951.5 5Com p. Ex. 113.00Yes Ove n702h5.268.307.74723. 156.2 3Com p. Ex. 123.00Yes AC1205mi n5.267.966.79559. 851.6 2Com p. Ex. 133.00Yes AC12010m in5.268.036.43467. 747.0 3 EXAMPLE 6

[0057] A tobacco raw material was treated in the same way as in Example 3, except that only flue-cured leaf tobacco was used as the tobacco raw material, and measurements were taken. The results are shown in Table 2.COMPARATIVE EXAMPLES 14 and 15

[0058] Tobacco raw materials were treated in the same way as in Example 6, except that the amount of basic substance added, and heating yes / no were changed as in Table 2. The results are shown in Table 2. Note that Comparative Example 14 shows an untreated tobacco raw material. Furthermore, 30 wt% of water was added instead of adding the basic substance in Comparative Example 15. Table 2Amount of basic substanc e added (wt%)Heatin gHeating temperatur e (°C)Heatin g timepH before basic substanc e addedpH after basic substanc e addedpH after heatin gAmoun t of furan analog s in smoke (µg)Ex. 63.00Yes AC1202h4.948.015.271319.3 5Comp . Ex. 140No--4.94--4465.6 5Comp . Ex. 150Yes AC1202h4.94-4.563456.6 7 EXAMPLE 7

[0059] A tobacco raw material was treated in the same way as in Example 3, except that only flue-cured cut lamina was used as the tobacco raw material, and measurements were taken. The results are shown in Table 3.COMPARATIVE EXAMPLES 16 and 17

[0060] Tobacco raw materials were treated in the same way as in Example 7, except that the amount of basic substance added, and heating yes / no were changed as in Table 3. The results are shown in Table 3. Note that Comparative Example 16 shows an untreated tobacco raw material. Furthermore, 30 wt% of water was added instead of adding the basic substance in Comparative Example 17. Table 3Amoun t of basic substan ce added (wt%)Heatin gHeating tempera ture (°C)Heatin g timepH before basic substan ce addedpH after basic substan ce addedpH after heatin gAmount of furan analogs in smoke (µg)Ex. 73.00Yes AC1202h5.118.15.54493.88Comp. Ex. 160No--5.11--2520.31Comp. Ex. 170Yes AC1202h5.11-4.731731.58 REFERENCE EXAMPLE 1

[0061] A tobacco raw material was treated in the same way as in Example 3, except that only Burley leaf tobacco was used as the tobacco raw material, and measurements were taken. The results are shown in Table 4.REFERENCE EXAMPLES 2-4

[0062] Tobacco raw materials were treated in the same way as in Reference Example 1, except that the amount of basic substance added was changed as in Table 4. The results are shown in Table 4. Note that Reference Example 2 shows an untreated tobacco raw material. Table 4Amoun t of basic substan ce added (wt%)Heatin gHeating tempera ture (°C)Heatin g timepH before basic substan ce addedpH after basic substan ce addedpH after heatin gAmount of furan analogs in smoke (µg)Ref. Ex. 13.00Yes AC1202h5.507.126.85125.44Ref. Ex. 20No--5.50--137.75Ref. Ex. 35.00Yes AC1202h5.507.677.71105.97Ref. Ex. 46.00Yes AC1202h5.508.007.9889.27

[0063] The embodiments include the following aspects. [1] A method for treating a tobacco raw material, the method comprising: a step of preparing a tobacco raw material having a pH of 8 or greater by adding a basic substance to a tobacco raw material; and a step of heating the tobacco raw material having a pH of 8 or greater until the pH reaches 6.3 or less. [2] The method as disclosed in [1], wherein the heating is performed in a closed space. [3] The method as disclosed in [1] or [2], wherein the heating is performed under pressurization. [4] The method as disclosed in any of [1] to [3], wherein a heating temperature in the heating is 100-200°C. [5] The method as disclosed in any of [1] to [4], wherein a heating time in the heating is 30 minutes-4 hours. [6] The method as disclosed in any of [1] to [5], wherein the tobacco raw material is of the flue-cured variety. [7] The method as disclosed in any of [1] to [6], wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the tobacco raw material after the treatment is 40 mg or less, and an amount of nicotine contained in 1 g of the tobacco raw material after the treatment is 10 mg or greater. [8] The method as disclosed in any of [1] to [7], wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less. [9] A tobacco raw material treated by the method as disclosed in any of [1] to [8].

[10] A flue-cured tobacco raw material wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the flue-cured tobacco raw material is 40 mg or less, and an amount of nicotine contained in 1 g of the flue-cured tobacco raw material is 10 mg or greater.

[11] The flue-cured tobacco raw material as disclosed in

[10] , wherein an amount of malic acid contained in 1 g of the flue-cured tobacco raw material is 30 mg or greater.

[12] A flue-cured tobacco raw material wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less.

[13] A heat-not-burn flavor inhaler containing the tobacco raw material as disclosed in any of [9] to

[12] .

[14] A heat-not-burn flavor inhalation system comprising: the heat-not-burn flavor inhaler as disclosed in

[13] ; and a heating device for heating the tobacco raw material in the heat-not-burn flavor inhaler. REFERENCE SIGNS LIST

[0064] 1 Heat-not-burn flavor inhaler 2 Tobacco-containing segment 3 Cooling segment 4 Center hole segment 5 Filter segment 6 Mouthpiece segment 7 Cylindrical member 8 Perforation 9 First filling layer 10 First inner plug wrapper 11 Outer plug wrapper 12 Mouthpiece lining paper 13 Heating device 14 Body 15 Heater 16 Metal tube 17 Battery unit 18 Control unit 19 Recess

Claims

1. A method for treating a tobacco raw material, the method comprising: a step of preparing a tobacco raw material having a pH of 8 or greater by adding a basic substance to a tobacco raw material; and a step of heating the tobacco raw material having a pH of 8 or greater until the pH reaches 6.3 or less.

2. The method as claimed in claim 1, wherein the heating is performed in a closed space.

3. The method as claimed in claim 1 or 2, wherein the heating is performed under pressurization.

4. The method as claimed in any one of claims 1 to 3, wherein a heating temperature in the heating is 100-200°C.

5. The method as claimed in any one of claims 1 to 4, wherein a heating time in the heating is 30 minutes-4 hours.

6. The method as claimed in any one of claims 1 to 5, wherein the tobacco raw material is of the flue-cured variety.

7. The method as claimed in any one of claims 1 to 6, wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the tobacco raw material after the treatment is 40 mg or less, and an amount of nicotine contained in 1 g of the tobacco raw material after the treatment is 10 mg or greater.

8. The method as claimed in any one of claims 1 to 7, wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the treated tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less.

9. A tobacco raw material treated by the method as claimed in any one of claims 1 to 8.

10. A flue-cured tobacco raw material wherein an amount of sugars consisting of glucose, fructose and sucrose contained in 1 g of the flue-cured tobacco raw material is 40 mg or less, and an amount of nicotine contained in 1 g of the flue-cured tobacco raw material is 10 mg or greater.

11. The flue-cured tobacco raw material as claimed in claim 10, wherein an amount of malic acid contained in 1 g of the flue-cured tobacco raw material is 30 mg or greater.

12. A flue-cured tobacco raw material wherein the total mass of furan, 2-methylfuran, furfural, 2-acetylfuran, 5-methylfuran, furfuryl alcohol, furyl hydroxymethyl ketone, and 5-hydroxymethylfurural in smoke generated when 0.2 g of the flue-cured tobacco raw material is heated for 5 minutes at 300°C, is 410 µg or less.

13. A heat-not-burn flavor inhaler containing the tobacco raw material as claimed in any one of claims 9 to 12.

14. A heat-not-burn flavor inhalation system comprising: the heat-not-burn flavor inhaler as claimed in claim 13; and a heating device for heating the tobacco raw material in the heat-not-burn flavor inhaler.

Images