EP4602930A1

EP4602930A1 - Tobacco formulation, tobacco sheet, tobacco filling material, smoking article, tobacco formulation production method, and tobacco sheet production method

Info

Publication number: EP4602930A1
Application number: EP22962029.9A
Authority: EP
Inventors: Masaki ROKUGAWA; Masashi Mizutani; Yusuke NANASAKI
Original assignee: Japan Tobacco Inc
Current assignee: Japan Tobacco Inc
Priority date: 2022-10-12
Filing date: 2022-10-12
Publication date: 2025-08-20
Also published as: KR20250074675A; JPWO2024079809A1; WO2024079809A1

Abstract

An object is to provide: a tobacco formulation that allows a tobacco sheet to be formed using a tobacco raw material, without the external addition of another poorly water-soluble substance raw material; as well as the tobacco sheet.

Provided is a tobacco sheet that includes (1) a poorly-water-soluble substance derived from a tobacco raw material, and (2) starch extracted from the tobacco raw material or from another tobacco raw material.

Description

TECHNICAL FIELD

The present invention relates to a tobacco sheet, a tobacco filler, a smoking product, a method for producing a tobacco formulation, and a method for producing a tobacco sheet.

BACKGROUND ART

Synthetic tobacco, a tobacco material that has been artificially shaped into paper form using leaf tobacco as a raw material, is also called a tobacco sheet. Examples of known methods for producing tobacco sheets include methods in which they are produced via a sheet-forming (paper making) process, methods in which they are produced via a slurry (casting) process, methods in which they are produced via a calendering (rolling) process, and methods in which they are produced via an extrusion moulding process.
In order to obtain a tobacco sheet of a predetermined strength, it is known that the particle size of the raw material tobacco should be within a predetermined range. For example, PTL 1 discloses that, the smaller the tobacco particle size, the greater the surface area of the tobacco particles that are bonded together, which allows the strength of the tobacco sheet to be increased, and in particular discloses that ensuring a mesh of 60 to 400 (56 µm to 375 µm) will allow a homogeneous sheet to be created. It is also stated in PTL 2 and PTL 3 that tobacco powder having a particle size of 30 to 120 µm should be used because tobacco web strength is impaired when homogenized to a tobacco particle size of 150 µm or more. There are also techniques in which tobacco having a nano-scaled particle size is used as raw material for sheets (PTL 4 and 5, and NPL 1).
Poorly water-soluble substances such as plant fibers other than tobacco are also often added in order to improve the formability and strength of tobacco sheets. In PTL 6, a cellulose material having a particle size of 200 µm to 4000 µm is added to and mixed with a tobacco raw material having a particle size of 30 µm to 120 µm in a mixing process prior to sheet formation; in mixtures such as this, the substances having two different particle sizes are intertwined, allowing the sheet structure to be stably preserved.
There is also a growing demand for tobacco sheets for use in heated tobacco (heat-not-burn smoking products). A tobacco raw material, an aerosol-generating agent, and a binder, for example, are mixed and formed into a tobacco sheet to produce tobacco sheets for heated tobacco. Ways to produce such tobacco sheets include adding poorly water-soluble cellulose pulp (PTL 7) and specifying the tobacco particle size (PTL 8) in order to improve sheet formability and strength. To produce such tobacco sheets, a poorly water-soluble metal or calcium carbonate is also added to improve thermal conductivity when heated (PTL 9 and 10).

CITATION LIST

PATENT LITERATURE

[PTL 1] EP Patent Application 0565360
[PTL 2] WO 2016/050471 A1
[PTL 3] WO 2017/089589 A1
[PTL 4] US 10196778 B2
[PTL 5] WO 2016/013946 A1
[PTL 6] US 10813381 B2
[PTL 7] US 10321707 B2
[PTL 8] US 10813381 B2
[PTL 9] US 2017/0079325 A1
[PTL 10] JP 4759523 B2

NON-PATENT LITERATURE

[NPL 1] Flexible cellulose nanopaper with high wet tensile strength, high toughness and tunable ultraviolet blocking ability fabricated from tobacco talk via a sustainable method," Qingbo Wang, Haishun Du, Fang Zhang, Yuedong Zhang, Meiyan Wu, Guang Yu, Chao Liu, Bin Li, and Hui Penga Journal of Material Chemistry, 2018, Vol 6 (27), pp. 13021-13030

SUMMARY OF INVENTION

TECHNICAL PROBLEM

As disclosed in PTL 6 and 7, adding a poorly water-soluble substance (such as plant fibers) other than tobacco to the tobacco raw material results in extra costs in the preparation of the poorly water-soluble substance as well as in extra time and labour in the process of blending the poorly water-soluble substance.
As a result of extensive research by the inventors of the present application undertaken in view of the above circumstances, it was discovered that a tobacco sheet can be formed, regardless of particle size, using a tobacco raw material in the form of a plant, without the external addition of a poorly water-soluble substance raw material (such as a fiber material). An object of the present invention is to provide: a tobacco formulation that allows a tobacco sheet to be formed using a tobacco raw material, without the external addition of another poorly water-soluble substance raw material; as well as the tobacco sheet.

SOLUTION TO PROBLEM

The above problem is solved by the following invention:

[1] A tobacco formulation comprising:
1. (1) a poorly water-soluble substance derived from a tobacco raw material;
2. (2) starch extracted from said tobacco raw material or from another tobacco raw material; and
3. (3) a medium.
[2] A tobacco sheet, comprising: (1') a poorly water-soluble substance derived from a tobacco starting material; and
(2') starch extracted from said tobacco raw material or from another tobacco raw material.
[3] The tobacco sheet according to [2], wherein the starch is starch extracted from said tobacco material.
[4] The tobacco sheet according to [2] or [3], wherein the starch is soluble starch.
[5] The tobacco sheet according to any of [2] to [4], wherein the primary particle size of the poorly water-soluble substance is 100 µm or less.
[6] The tobacco sheet according to any of [2] to [5], wherein the starch content in the tobacco sheet is 10 wt% or less.
[7] The tobacco sheet according to any of [2] to [6], wherein the tobacco raw material from which the poorly water-soluble substance is derived comprises leaf tobacco.
[8] The tobacco sheet according to any of [2] to [7], wherein the tobacco raw material from which the poorly water-soluble substance is derived comprises an alkaloid.
[9] The tobacco sheet according to any of [2] to [8], further comprising an aerosol-generating agent.
[10] The tobacco sheet according to [9], wherein the aerosol-generating agent comprises glycerin, 1,2-propanediol, 1,3-propanediol, or a mixture thereof.
[11] The tobacco sheet according to any of [2] to [10], further comprising glucan.
[12] The tobacco sheet according to [11], wherein the glucan comprises tamarind gum, guar gum, locust bean gum, gellan gum, pullulan, or a mixture thereof.
[13] The tobacco sheet according to any of [2] to [12], wherein no pulp is included.
[14] The tobacco sheet according to any of [2] to [13], which is a cast sheet.
[15] The tobacco sheet according to any of [2 to [14], which is a molded body of the tobacco formulation according to [1].
[16] Tobacco filler comprising the tobacco sheet according to any of [2] to [15].
[17] A smoking product comprising the tobacco filler according to [16].
[18] The smoking product according to [17], which is a heat-not-burn smoking product.
[19] A method for producing the tobacco formulation according to [1], comprising the step of heating the tobacco raw material in the medium to extract the starch.
[20] A method for producing the tobacco sheet
- according to any of [2] to [15], comprising
- a step in which the tobacco formulation is produced by the method in [19], and
- a step in which the tobacco formulation is spread onto a substrate and is then dried.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention makes it possible to provide: a tobacco formulation that allows a tobacco sheet to be formed using a tobacco raw material, without the external addition of another poorly water-soluble substance raw material; as well as the tobacco sheet.

BRIEF DESCRIPTION OF DRAWINGS

[Figure 1] Figure 1 is a cross-sectional schematic view showing an example of a heat-not-burn smoking system.
[Figure 2] Figure 2 is a cross-sectional schematic view showing an example of a heat-not-burn smoking product.

DESCRIPTION OF EMBODIMENTS

The present invention is described in detail below. As used in the present invention, the range "X-Y"includes X and Y as the end values.

1. Tobacco Formulation

The tobacco formulation of the present embodiment comprises:

(1) a poorly water-soluble substance derived from a tobacco raw material;
(2) starch extracted from said tobacco raw material or from another tobacco raw material; and
(3) a medium.

(1) Poorly water-soluble substance derived from a tobacco raw material

The poorly water-soluble substance of the present invention is derived from a tobacco raw material. As used in the present application, a poorly water-soluble substance means a substance having a solubility in water of less than 20 µ g/mL at 85°C, which can be obtained in the form of a residue after boiling and extraction of the tobacco raw material. The poorly water-soluble substance can be obtained in the form of a residue of the tobacco raw material by boiling and extracting the tobacco raw material under predetermined conditions, and extracting starch from the tobacco raw material, as shown in Example 1 or Example 2 below (preparation of tobacco formulation and tobacco sheet), for example,
It can be determined whether the poorly water soluble substance is or is not derived from a tobacco raw material by, for example, analyzing the isotope fractions of the poorly water-soluble substance and measuring the 13C/12C ratio.
The poorly water-soluble substance can contain poorly water-soluble fibers or can consist of poorly water soluble fibers.
The shape of the poorly water-soluble substance in the tobacco formulation is not limited but is preferably in granular form.
The lower limit of the primary particle size (D90) of the poorly water-soluble substance is not particularly limited but, in the interests of preserving the sheet structure, is preferably 20 µm or more, more preferably 50 µm or more, and ideally 100 µm or more. The lower limit of the primary particle size (D90) of the poorly water-soluble substance can also be 5 µm or more, or 10 µm or more. The upper limit of the primary particle size (D90) of the poorly water-soluble substance is not particularly limited but, in the interests of sheet structure homogeneity, is preferably 500 µm or less, more preferably 250 µm or less, and ideally 100 µm or less. The upper limit of the primary particle size (D90) of the poorly water-soluble substance can be 80 µm or less, 50 µm or less, or 30 µm or less. Any combination of upper and lower limits of the primary particle size of the above poorly water-soluble substance can be used. The primary particle size (D90) of the poorly water-soluble substance can be determined according to the procedures and conditions described in "(1) Determination of Particle Size of Poorly Water-Soluble Substance" in the Examples below. Reducing the primary particle size of the poorly water-soluble substance can increase the surface area of the tobacco particles that are bonded together and can increase the strength of the tobacco sheet.
The lower limit of the content of the poorly water-soluble substance in the tobacco formulation is not particularly limited but, in the interests of ensuring functionality as a substrate, is preferably 5 wt% or more, more preferably 10 wt% or more, and ideally 15 wt% or more, but can also be 20 wt% or more, 75 wt% or more, or 90 wt% or more. The upper limit of the content of the poorly water-soluble substance in the tobacco formulation is not particularly limited but can be 95 wt% or less, 80 wt% or less, 70 wt% or less, 50 wt% or less, or 35 wt% or less. Any combination of upper and lower limits of the content of the poorly water-soluble substance in the tobacco formulation can be used.
The content of the poorly water-soluble substance in the tobacco formulation can be the value calculated on the basis of the solids, minus the medium. The content of the poorly water-soluble substance in the tobacco formulation can be determined according to the procedures and conditions described in "(3) Determination of Content of Poorly Water-Soluble Substance" in the Examples below, and can be calculated as a percentage of the weight (wt%) of the resulting dry product relative to the weight of the solids of the tobacco formulation.
The content of the poorly water-soluble substance in the tobacco formulation can also be calculated by the Prosky method Specifically, samples of the tobacco formulation are obtained, and the starch contained in the samples is randomly broken down by thermostable α-amylase into small amounts of glucose. The peptide bonds of protein included in the samples are then broken down by protease. The sugar chains degraded by the thermostable α-amylase are ultimately broken down by amyloglucosidase into one glucose molecule. Ethanol is then added to the samples to produce precipitate, the precipitate is then recovered via suction filtration, and the resulting precipitate is washed with ethanol and acetone. The precipitate is washed with ethanol and acetone to flush out enzymatically un-degraded lipids in the precipitate. The washed precipitate is dried overnight, and the dry weight is determined. However, the filtered residue obtained via the above suction filtration includes leftover un-degraded sample-derived proteins or enzyme-derived proteins and inorganic matter (ash). The proteins and ash are therefore separately quantified and subtracted from the dry weight to calculate the amount of the poorly water-soluble substance.
The above proteins are calculated by BSA assay, which is based primarily on a two-stage reaction. In the first stage, divalent copper ions (Cu²⁺) contained in the kit are reduced to monovalent copper ions (Cu⁺) by peptide bonds in the protein solution. The amount of Cu²⁺ that is reduced is proportional to the amount of protein contained in the solution. In the second stage, two molecules of bicinchoninic acid (BCA) are coordinated to Cu⁺ to form a bluish-purple complex exhibiting strong absorption at 562 nm. The amount of protein is calculated via colourimetric determination by spectrophotometry of the complex. The ash content is calculated based on the weight of a given amount ashed at a temperature of 550 to 600°C.

(Tobacco raw material)

The above tobacco raw material is raw material derived from a tobacco plant, such as tobacco leaf, aged tobacco leaf, cut tobacco, tobacco powder, tobacco raw material parts other than leaves, such as stems and stem waste, and processed or waste products obtained in the course of tobacco raw material processing. Tobacco leaf is a generic term for harvested tobacco leaves before they have been aged. One mode of ageing includes curing. Cut tobacco is aged tobacco leaf, for example, that has been cut to a predetermined size. Tobacco powder is tobacco leaves, for example, that have been ground.
A number of varieties of tobacco can be used as the tobacco raw material. Examples of tobacco varieties include yellow, Burley, orient, or native varieties, as well as Nicotiana tabacum and Nicotiana rustica varieties. These varieties can also be used alone, but in order to obtain a desired flavor, any varieties over the course from the harvest of tobacco leaves to the processing of the various types in which aged tobacco leaf is used in heat-not-burn tobacco products (specifically, processed tobacco leaves) can also be blended for use. Details on tobacco varieties are disclosed in "Dictionary of Tobacco, Tobacco Academic Studies Center, 2009.3.31."
The tobacco raw material from which the poorly water-soluble substance is derived can include alkaloids in the interests of palatability.
The types of alkaloids are not particularly limited, but nicotine, nornicotine, or mixtures thereof can be used.
(2) Starch Extracted from the Tobacco Raw Material or from Another Tobacco Raw Material
In the present invention, starch may be extracted from the tobacco raw material included in the tobacco formulation, or may be extracted from a separate tobacco raw material that is not included in the tobacco formulation. Specifically, the tobacco formulation in one embodiment comprises a tobacco ingredient X and starch extracted from said X, in another embodiment comprises tobacco raw material X and starch extracted from a tobacco raw material Y other than X, and in yet another embodiment comprises the tobacco raw material X, starch extracted from said X, and starch extracted from a tobacco raw material Y other than X.
Starch is present in the cells of the tobacco raw material. The extraction conditions are therefore adjusted to allow the starch to be released from the cells. The extraction conditions are described below.
In the present invention, the starch functions as a binder to join the poorly water-soluble substance together. Tobacco varieties among the above that contain large amounts of starch are therefore preferred. Thus, in one embodiment, the tobacco raw material is preferably tobacco leaf containing 0.1 to 20 wt% starch, and more preferably tobacco leaf containing 1 to 2 wt% starch. Examples of such tobacco leaf include the yellow or Burley varieties. The tobacco leaf of the former contains about 2 to 5 wt% starch. The tobacco leaf of the latter contains about 0.1 to 0.5 wt% starch.
The use of starch that functions as a binder allows a tobacco formulation that does not contain any binders other than starch to be produced. As used here in the present application, the expression "does not contain" a specific ingredient means that said ingredient is intentionally not added but can be included in the form of impurities. When a binder other than starch is contained in the form of an impurity, the content of the binder other than starch in the tobacco formulation can be 2 wt% or less, 1 wt% or less, or 0.2 wt% or less.
The type of the above starch is not particularly limited, but soluble starch, insoluble starch, or mixtures thereof can be used, among which the use of soluble starch is preferred in the interests of ensuring homogeneous mixing based on water solubility.
The lower limit of the starch content in the tobacco formulation is not particularly limited but is preferably 1 wt% or more, 2 wt% or or more, and ideally 2.5 wt% or more. The upper limit of the starch content in the tobacco formulation is not particularly limited but is preferably 50 wt% or less, more preferably 40 wt% or less, and ideally 25 wt% or less. The upper limit of the starch content in the tobacco formulation can be 20 wt% or less, 15 wt% or less, 10 wt% or less, 5 wt% or less, or 4 wt% or less. Any combination of upper and lower limits of the starch content in the tobacco formulation can be used. A starch content of 1 wt% or more will allow the tobacco sheet to be made stronger. As to the upper limit of the starch content (50 wt% or less), 50 wt% starch of a starch that is viscous and functions as a binder will be sufficient, and increasing the amount beyond that will not improve its function as a binder. Ensuring that the starch content in the tobacco formulation is within a numerical range between the above lower and upper limits will result in a suitable amount of starch functioning as a binder and will allow the structure of the resulting tobacco sheet to be preserved.
The content of the starch in the tobacco formulation can be the value calculated on the basis of the solids, minus the medium. The content of the starch in the tobacco formulation can be determined according to the procedures and conditions described in "(4) Determination of Starch Content" in the Examples below, and can be calculated as a percentage of the weight (wt%) of the starch relative to the weight of the solids of the tobacco formulation.

(3) media

The medium is preferably a liquid at room temperature (about 23°C), specific examples of which include water or water-soluble organic solvents. Examples of water-soluble organic solvents include C1-3 linear or branched alcohols, or C4-7 ethers. These can be used alone or in combination as the medium. In the interests of handling, the medium is preferably a mixture of water and a water-soluble organic solvent, and more preferably water.
The content of the medium in the tobacco formulation is not particularly limited, but in the interests of thermal energy efficiency when heated, the content is preferably 20 to 80 wt%, more preferably 30 to 75 wt%, and ideally 50 to 70 wt%. The content of the medium in the tobacco formulation can be calculated based on the dry weight using an IR moisture analyzer.
The tobacco formulation of the present invention can be produced, for example, by mixing the tobacco raw material and the medium to obtain a mixture, and then boiling and extracting the mixture to extract starch from the tobacco raw material, as shown in Example 1 or Example 2 below (Preparation of Tobacco Formulation and Tobacco Sheet).
The cellulose naturally occurring in the tobacco raw material can be used as a reinforcing material in the present invention. Thus, in one embodiment, the tobacco raw material is preferably tobacco leaf containing 4 to 15 wt% cellulose, and more preferably tobacco leaf containing 5 to 13 wt% cellulose. Examples of varieties include the yellow or Burley varieties. The leaf tobacco of the former contains about 6 to 8 wt % cellulose. The leaf tobacco of the latter also contains about 10 to 12 wt % cellulose.
The aforementioned poorly water-soluble substance can contain the above cellulose.

(Characteristics of the Tobacco Formulation)

As described below, the tobacco formulation of the present invention is useful as a tobacco material. When starch is derived from a tobacco raw material, it has a high affinity with the poorly water-soluble substance derived from the same tobacco raw material. In particular, in embodiments comprising the poorly water-soluble substance derived from the tobacco raw material X and the starch extracted from said X, some or all of the starch is removed from the tobacco raw material X to form the poorly water-soluble substance, thus allowing the medium or other components to be retained at sites where the starch in the poorly water-soluble substance has been removed. It is thus believed that there is particularly high affinity between the starch and the poorly water-soluble substance. The poorly water-soluble substance derived from the tobacco raw material thus has high affinity with the starch, for example, or separately added additives, for example. The tobacco formulation of the present invention can thus form a stronger tobacco sheet, for example.

2. Tobacco sheet

The tobacco sheet of the present invention comprises:

(1') a poorly water-soluble substance derived from a tobacco raw material; and
(2') starch extracted from said tobacco raw material or from another tobacco raw material.

(1') Poorly water-soluble substance derived from a tobacco raw material

The various structural elements, such as the type, configuration, or primary particle size, of the poorly water-soluble substance contained in the tobacco sheet are not particularly limited, but can be the same as the various structural elements described in "(1) Poorly Water-Soluble Substance Derived from Tobacco Raw Material" in "1. Tobacco Formulation" noted above.
The lower limit of the content of the poorly water-soluble substance in the tobacco sheet is not particularly limited but, in the interests of ensuring functionality as a substrate, is preferably 5 wt% or more, more preferably 10 wt% or more, and ideally 15 wt% or more, but can also be 20 wt% or more, 75 wt% or more, or 90 wt% or more. The upper limit of the content of the poorly water-soluble substance in the tobacco sheet is not particularly limited but can be 95 wt% or less, 80 wt% or less, 70 wt% or less, 50 wt% or less, or 35 wt% or less. Any combination of upper and lower limits of the content of the poorly water-soluble substance in the tobacco sheet can be used.
The tobacco sheet can be formed by removing the medium from the tobacco formulation. Therefore, as described in "(3) Determination of Content of Poorly Water-Soluble Substance" in the Examples below, the content (wt %) (calculated on the basis of solids) of the poorly water-soluble substance in the tobacco formulation described above can be considered to be equal to the content (wt%) of the poorly water-soluble substance in the tobacco sheet.
The content of the poorly water-soluble substance in the tobacco sheet can also be calculated based on the aforementioned Prosky method.
The tobacco raw material serving as the poorly water-soluble substance raw material is not particularly limited but can be the same as the tobacco raw material described in "1. Tobacco raw material" noted above.

(2') Starch Extracted from the Tobacco Raw Material or from Another Tobacco Raw Material

The various structural elements, such as the type, of the starch contained in the tobacco sheet are not particularly limited, but can be the same as the various structural elements described in "(2) Starch Extracted from the Tobacco Raw Material or from Another Tobacco Raw Material" in "1. Tobacco Formulation" noted above.
The lower limit of the starch content in the tobacco sheet is not particularly limited but is preferably 1 wt% or more, 2 wt% or or more, and ideally 2.5 wt% or more. The upper limit of the starch content in the tobacco sheet is not particularly limited but is preferably 50 wt% or less, more preferably 40 wt% or less, and ideally 25 wt% or less. The upper limit of the starch content in the tobacco sheet can be 20 wt% or less, 15 wt% or less, 10 wt% or less, 5 wt% or less, or 4 wt% or less. Any combination of upper and lower limits of the starch content in the tobacco sheet can be used. A starch content of 1 wt% or more will allow the tobacco sheet to be made stronger. As to the upper limit of the starch content (50 wt% or less), 50 wt% starch of a starch that is viscous and functions as a binder will be sufficient, and increasing the amount beyond that will not improve its function as a binder. Ensuring that the starch content in the tobacco sheet is within a numerical range between the above lower and upper limits will result in a suitable amount of starch functioning as a binder and will allow the structure of the resulting tobacco sheet to be preserved. The tobacco sheet can be formed by removing the medium from the tobacco formulation. Therefore, as described in "(4) Determination of Starch Content" in the Examples below, the starch content (wt %) (calculated on the basis of solids) in the tobacco formulation described above can be considered to be equal to the starch content (wt%) in the tobacco sheet.
The tobacco sheet can comprise ingredients derived from the tobacco raw material. The ingredients derived from the tobacco raw material can comprise poorly water-soluble substances derived from the above tobacco raw material as well as starch extracted from the above tobacco raw material.
The lower limit of the content of the tobacco raw material-derived ingredients in the tobacco sheet is not particularly limited but, in the interests of ensuring functionality as a substrate, is preferably 10 wt% or more, more preferably 15 wt% or more, and ideally 20 wt% or more, but can also be 75 wt% or more, or 90 wt% or more. The upper limit of the content of the tobacco raw material-derived ingredients in the tobacco sheet is not particularly limited but can be 80 wt% or less, 70 wt% or less, or 50 wt% or less. Any combination of upper and lower limits of the tobacco raw material-derived ingredients in the tobacco sheet can be used.
The content of the ingredients derived from the tobacco raw material in the tobacco sheet can be calculated as the proportion of the weight of said tobacco raw material relative to the total weight of the tobacco raw material that is used and any externally added ingredients.

(Other Ingredients)

The tobacco sheet can further comprise an aerosol-generating agent.
The aerosol-generating agent is not particularly limited but can include glycerin, 1,2-propanediol, 1,3-propanediol, or a mixture of two or more of these.
The content of the aerosol-generating agent in the tobacco sheet is not particularly limited, but in the interests of the volume of smoke during smoking, is preferably 10 to 50 wt%, more preferably 15 to 45 wt%, and ideally 20 to 25 wt%.
The tobacco sheet can further comprise glucan. Glucan is a type of binder, as described below.
Examples of glucan are not particularly limited but can include tamarind gum, guar gum, locust bean gum, gellan gum, pullulan, or a mixture of two or more of these.
The content of the glucan in the tobacco sheet is not particularly limited, but in the interests of formability, is preferably 0.1 to 5 wt%, more preferably 0.5 to 2 wt%, and ideally 1. 0-1. 5% by weight.
The tobacco sheet can comprise a binder. On the other hand, the use of starch that functions as a binder in the present invention allows a tobacco sheet that does not contain any binders other than starch to be produced. If the tobacco sheet contains a binder in the form of an impurity, the content of the binder other than starch in the tobacco sheet can be 3 wt% or less, 1 wt% or less, or 0.5 wt% or less.
In cases where none is preferably added, the tobacco sheet can be pulp-free. If the tobacco sheet contains pulp in the form of an impurity, the content of the pulp in the tobacco sheet can be 3 wt% or less, 1 wt% or less, or 0.5 wt% or less.
The tobacco sheet of the present invention can be in the form of, but is not particularly limited to, a sheet made by a paper-making technique or a cast sheet, for example, but is preferably a cast sheet in the interests of producing a low-density sheet. Details on various types of tobacco sheets are disclosed in "Dictionary of Tobacco, Tobacco Academic Studies Center, 2009. 3. 31."
The tobacco sheet of the present invention is not particularly limited, but can be made in the form of the molded tobacco formulation described in the "1.Tobacco Formulation" section described above.

3. Production Method

(Method for Producing Tobacco Formulation)

The tobacco formulation of the present invention is preferably produced by a method comprising the step of heating the tobacco raw material in a medium to extract the starch noted above. The tobacco formulation can be in the form of that described in "1.Tobacco Formulation" above.

(1) Temperature

The starch in the tobacco formulation is contained in the cell walls of the tobacco raw material. The temperature must therefore be high enough to allow the starch to be released from the cells. From this perspective, the temperature during extraction is preferably 100 to 125°C, more preferably 105 to 120°C, and ideally 110 to 119°C. The cellulose can be efficiently released from the cells at this temperature.

(2) Pressure

The pressure must be high enough to allow the starch to be released from the cells. From this perspective, the average pressure during extraction is preferably 20 to 117 kPa, more preferably 50 to 110 kPa, and ideally 85 to 95 kPa. The maximum pressure during extraction is preferably 70 to 117 kPa, more preferably 80 to 116.5 kPa, and ideally 90 to 116.5 kPa. Ensuring that the average pressure or maximum pressure is within said numerical range will allow the cellulose to be efficiently released from the cells.

(3) Time

The time must be long enough to allow the starch to be released from the cells. From this perspective, the extraction process is preferably 20 to 90 minutes long, more preferably 60 to 80 minutes long, and ideally 65 to 70 minutes long. Ensuring that the duration of the extraction process is within the above numerical range will allow the cellulose to be efficiently released from the cells.

(4) Number of Times

Repeating the extraction process will allow more starch to be released from the cells. From this point of view, the extraction process can be carried out 1 to 2 times, 3 to 4 times, or 5 to 10 times; the higher the number of times, the more efficiently the starch can be released. Ensuring that the extraction process is carried out a number of times within the above numerical range will allow the cellulose to be efficiently released from the cells.

(5) Atmosphere

The starch is preferably extracted from the tobacco raw material in a closed system. This is to prevent the tobacco raw material from losing flavour.

(6) Grinding

In the interests of extraction efficiency, the tobacco raw material undergoing extraction preferably has a large surface area. A process for grinding the tobacco raw material should therefore be provided in advance to allow the powdered tobacco raw material to be extracted. In cases such as this, dry grinding is preferred. Known machines can be used for dry grinding. The particle size distribution of the powdered tobacco raw material is not limited but should preferably have a D90 of less than 500 µm and more preferably a D90 less than 100 µm. The lower limit of the D90 is not limited, but is substantially to 5 µm or more.
Alternatively, the tobacco raw material may be ground at the same time as when extracted. Specifically, the tobacco raw material can be extracted while wet ground. Wet grinding is preferably carried out in a closed system. The particle size distribution of the wet ground tobacco raw material is as described above.
The method for producing the tobacco formulation can further comprise the step of adding an aerosol-generating agent, a binder, or a combination thereof. An aerosol-generating agent or binder as described in "(Other Ingredients)" in "2. Tobacco Sheet" above can be used.
The method for producing the tobacco formulation can be one that does not comprise a step for adding another poorly water-soluble substance pulp that contains pulp. Other poorly water-soluble substances are poorly water-soluble substances other than the poorly water-soluble substances derived from the tobacco raw material described above. In the present application, the tobacco sheet can be formed without externally adding another poorly water-soluble substance raw material to the tobacco formulation.

(Method for Producing Tobacco Sheet)

The type of methods for producing the tobacco sheet of the present invention is not particularly limited, and known methods such as paper-making techniques and casting methods can be employed. Of these methods, casting methods are preferred in the interests of the homogeneity of the resulting sheet.
The method for producing the tobacco sheet of the present invention can comprise a step in which a tobacco formulation is prepared by the method described above and a step in which the tobacco formulation is spread on a substrate and is then dried. The method for producing the tobacco sheet need not comprise the step of grinding the tobacco formulation if the tobacco raw material is ground in the step for preparing the tobacco formulation.

Examples of methods for forming a tobacco sheet via a casting method (slurry method) include methods comprising the following steps:

(1) a step for mixing ground aged tobacco with water, optionally pulp, and optionally a binder to obtain a mixture (homogenization step); and
(2) a step for thinly spreading (casting) and drying the mixture into a tobacco sheet.

The shape of the tobacco sheet can be adjusted, as appropriate, but in one mode the thickness is 50 to 500 µm. The tobacco sheet can be cut to produce cuts or strands. The tobacco sheet can also be ground to produce powder.

4. Tobacco Filler and Smoking Product

The tobacco filler of the present invention comprises the tobacco sheet described above.
The smoking product of the present invention also comprises the tobacco filler.
The smoking product of the present invention can be a heat-not-burn smoking product.
As used in the present application, "smoking product" means an aspiration product upon which a user draws to experience flavour. Smoking products can be broadly divided into burning smoking products, such as conventional cigarettes, and heat-not-burn smoking products.
Examples of burning smoking products include cigarettes, pipes, kiserus (Japanese smoking pipes), cigars, and cigarillos.
Heat-not-burn smoking products (heated smoking products) may be heated by a heating device that is separate from the product, or by a heating device that is integrated with the product. In the former type of smoking product (separate heating device), the heat-not-burn smoking product and the heating device are collectively referred to as a "heat-not-burn smoking system." An example of a heat-not-burn smoking system is described below with reference to Figures 1 and 2.
Figure 1 is a cross-sectional schematic view showing an example of a heat-not-burn smoking system before the heater 12 is inserted into the smoking segment 20A of the heat-not-burn smoking product 20. During use, the heater 12 is inserted in the smoking segment 20A. Figure 2 is a cross-sectional view of a heat-not-burn smoking product 20.
As shown in Figure 1, the heat-not-burn smoking system comprises a heat-not-burn smoking product 20 and a heating device 10 which heats the smoking segment 20A from the inside. However, the heat-not-burn smoking system is not limited to the configuration shown in Figure 1.
The heating device 10 shown in Figure 1 comprises a body 11 and a heater 12. The body 11 may comprise a battery unit and a control unit (not shown). The heater 12, which can be a heater based on electrical resistance, is inserted into the smoking segment 20A to heat the smoking segment 20A.
In Figure 1, the smoking segment 20A is heated from the inside, but embodiments of the heat-non-burn smoking product 20 are not limited to this; in other embodiments, the smoking segment 20A is heated from the outside.
The heating temperature of the heating device 10 is not particularly limited, but is preferably 400°C or below, more preferably 50 to 400°C, and even more preferably 150 to 350°C. The heating temperature refers to the temperature of the heater 12 of the heating device 10.
As shown in Figure 2, the heat-not-burn smoking product 20 (referred to below simply as "the smoking product 20") has a cylindrical shape. In circumference, the length of the smoking product 20 is preferably 16 mm to 27 mm, more preferably 20 mm to 26 mm, and even more preferably 21 mm ato 25 mm. The total length (horizontal length) of the smoking product 20 is not particularly limited, but is preferably 40 mm to 90 mm, more preferably 50 mm to 75 mm, and even more preferably 50 mm to 60 mm.
The smoking product 20 consists of a smoking segment 20A and a filter portion 20C constituting the mouthpiece, which are connected by a connecting portion 20B.
The smoking segment 20A is cylindrical, the total length (axial length) of which is, for example, preferably 5 to 100 mm, more preferably 10 to 50 mm, and even more preferably 10 to 25 mm. The shape of the cross-section of the smoking segment 20A is not particularly limited, but can be circular, elliptical, or polygonal, for example.
The smoking segment 20A has a smoking composition sheet or material 21 derived therefrom, around which is wrapped a wrapper 22.
The filter portion 20C is cylindrical. The filter portion 20C has a rod-shaped first segment 25 that is made by being filled with cellulose acetate fibers, and a rod-shaped second segment 26 that is similarly made by being filled with cellulose acetate fibers. The first segment 25 is located on the smoking segment 20A side. The first segment 25 may have a hollow portion. The second segment 26 is located on the mouthpiece side. The second segment 26 is solid. The first segment 25 is composed of a first filling layer (cellulose acetate fibers) 25a and an inner plug wrapper 25b that is wrapped around the first filling layer 25a. The second segment 26 consists of a second filling layer (cellulose acetate fibers) 26a and an inner plug wrapper 26b that is wrapped around the second filling layer 26a. The first and second segments 25 and 26 are connected by an outer plug wrapper 27. The outer plug wrapper 27 is adhered to the first segment 25 and second segment 26 by a vinyl acetate emulsion-based adhesive, for example.
The length of the filter portion 20C can be 10 to 30 mm, for example, the length of the connecting portion 20B can be 10 to 30 mm, for example, the length of the first segment 25 can be 5 to 15 mm, for example, and the length of the second segment 26 can be 5 to 15 mm, for example. The lengths of these individual segments are examples, and can be modified, as appropriate, depending on, for example, the manufacturability, the required quality, and the length of the smoking segment 20A.
For example, the first segment 25 (centre hole segment) is composed of the first filling layer 25a having one or more hollow portions, and the inner plug wrapper 25b that covers the first filling layer 25a. The first segment 25 has the function of increasing the strength of the second segment 26. The first filling layer 25a of the first segment 25 is, for example, densely filled with cellulose acetate fibers. To the cellulose acetate fibers are added and cured a triacetin-containing plasticizer, in an amount of 6 to 20% by mass, for example, relative to the mass of the cellulose acetate. The hollow portion of the first segment 25 may, for example, have an inner diameter of φ 10 to φ 5 0 mm.
The first filling layer 25a of the first segment 25 may, for example, be configured with a relatively high fiber filling density, or may be the same as the fiber filling density of the second filling layer 26a of the second segment 26 described below. Thus, when drawn, air or aerosol will flow only through the hollow portion, and virtually no air or aerosol will flow through the first filling layer 25a. In cases where, for example, less of a filtration-induced reduction in the aerosol component is desired in the second segment 26, the length of the second segment 26 can be shortened, for example, to allow the first segment 25 to be lengthened accordingly.
Replacing the shortened second segment 26 with the first segment 25 will effectively increase aerosol delivery. The first filling layer 25a of the first segment 25 is a fiber filled layer, and the user therefore will not feel any discomfort when touching the outside during use.
The second segment 26 is composed of the second filling layer 26a and an inner plug wrapper 26b that covers the second filling layer 26a. The second segment 26 (filter segment) is filled with cellulose acetate fibers in a commonly used density, and has a commonly used aerosol filtration capacity.
The filtration capacity for filtering the aerosol (mainstream smoke) released from the smoking segment 20A may differ between the first segment 25 and the second segment 26. At least one of the first segment 25 or the second segment 26 may comprise flavouring. The filter portion 20C may have any structure, and may be a structure having a plurality of segments as described above, or may be composed of a single segment. The filter portion 20C may be composed of one segment. In such cases, the filter portion 20C may be composed of either the first segment or the second segment.
The connecting portion 20B is cylindrical. The connecting portion 20B has a paper tube 23 that is cylindrically formed using cardboard, for example. The connecting portion 20B may be filled with a cooling member for cooling the aerosol. Examples of cooling members includes a sheet of a polymer such as polylactic acid, which can be folded and filled. A support that prevents the position of the smoking segment 20A from moving around may furthermore be provided between the smoking segment 20A and the connecting portion 20B. The support can be composed of known materials such as a centre hole filter of the kind in the first segment 25.
A wrapper 28 is cylindrically wrapped around the outside of the smoking segment 20A, connecting portion 20B, and filter portion 20C to integrally join these parts. One surface (the inner surface) of the wrapper 28 is coated with a vinyl acetate-emulsion-based adhesive, over the entire surface or substantially the entire surface, except near the ventilation holes 24. A plurality of ventilation holes 24 are externally formed by a laser process after the smoking segment 20A, connecting portion 20B, and filter portion 20C have been integrated by the wrapper 28.
The ventilation holes 24 comprise two or more through-holes that pass through the connecting portion 20B in the thicknesswise direction. The two or more through-holes are formed so as to be radially arranged, as viewed along a line extending through the central axis of the smoking product 20. In the present embodiment, the ventilation holes 24 are provided in the connecting portion 20B, but may be provided in the filter portion 20C. In this embodiment, the two or more through-holes of the ventilation holes 24 are provided in a single row at a constant interval in a circular pattern, but may be provided in two rows at a constant interval in a circular pattern, where the one or two rows of the ventilation holes 24 may be provided discontinuously or irregularly. When a user holds the mouthpiece in the mouth and draws, outside air is taken into the mainstream smoke through the ventilation holes 24. However, no ventilation holes 24 need be provided.

EXAMPLES

EXAMPLE 1

(Preparation of Tobacco Formulation and Tobacco Sheet)

1000 g of yellow variety tobacco was processed in a small grinder (High-Speed Mill, by Labonect, Co. Ltd.) to obtain coarse yellow variety tobacco (referred to below as "tobacco sample"). 300 g of the resulting tobacco sample and 1000 g of water were introduced into and mixed in a switchable pressure cooker (Quick Eco, by Pearl Metal Co., Ltd.), and the resulting liquid mixture was boiled under the following conditions.

Pressure: Maximum pressure 90 kPa; average pressure 80 kPa
Temperature: 119°C
Time: 30 minutes

1000 g of water is added to and mixed with the boiled mixture in the pressure cooker, and the resulting mixture was then boiled a second time under the following conditions.

The mixture boiled a second time was cooled to 35°C, and the moisture content of the mixture, as determined by IR moisture analysis using an IR moisture analyzer (MB45, by OHAUS), was 80 wt%.
15 g guar gum, 6 g CMC (carboxymethylcellulose), and 43.5 g glycerin were added to and mixed with the mixture, after the moisture had been determined, in the pressure cooker, giving a liquid mixture. 800 g of the resulting liquid mixture was collected and was treated with a defibrillator (high-speed dispersion high-shear mixer, by Silverson) as 800 g of water was added to effect wet grinding and extraction. The conditions of the wet grinding are given below.

Rotating speed: 7000 rpm
Time: 10 minutes
*The 800 g of water was gradually added over a 10-minute period to the liquid mixture

The aforementioned wet grinding and extraction resulted in a suspension (tobacco formulation) comprising a poorly water-soluble substance derived from yellow tobacco, starch extracted from yellow tobacco, and water (as the medium).
The suspension obtained as described above was then spread out on a stainless steel sheet and allowed to dry naturally at room temperature to produce a slurry sheet (tobacco sheet) (thickness: 1 mm).
The content of the ingredients derived from the tobacco raw material in the tobacco sheet of Example 1 was 82.3 wt%, as determined by calculating the proportion of the weight of the tobacco raw material relative to the total weight of the tobacco raw material (tobacco sample) and any externally added ingredients (guar gum, CMC, and glycerin) that had been used.

EXAMPLE 2

(Preparation of Tobacco Formulation and Tobacco Sheet)

300 g of the tobacco sample noted in Example 1 above and 1000 g of water were introduced into and mixed in a switchable pressure cooker (Quick Eco, by Pearl Metal Co., Ltd.), and the resulting liquid mixture was boiled under the following conditions. The boiling process was repeated twice.

1000 g of water was added to and mixed with the boiled mixture in the pressure cooker, and the resulting mixture was then boiled a third time under the following conditions.

The mixture boiled a third time was cooled to 25°C, and the moisture content of the mixture, as determined by IR moisture analysis using an IR moisture analyzer (MB45, by OHAUS), was 80 wt%.
15 g guar gum, 6 g CMC (carboxymethylcellulose), and 43.5 g glycerin were added to and mixed with the mixture, after the moisture had been determined, in the pressure cooker, giving a liquid mixture. 800 g of the resulting liquid mixture was collected and was treated with a defibrillator (high-speed dispersion high-shear mixer, by Silverson) as 800 g of water was added to effect wet grinding and extraction. The conditions of the wet grinding are given below.

Rotating speed: 4500 rpm
Time: 20 minutes
*The 800 g of water was gradually added over a 20-minute period to the liquid mixture

The aforementioned wet grinding and extraction resulted in a suspension (tobacco formulation) comprising a poorly water-soluble substance derived from yellow tobacco, starch extracted from yellow tobacco, and water (as the medium).
The suspension obtained as described above was then spread out on a stainless steel sheet and allowed to dry naturally at room temperature to produce a slurry sheet (tobacco sheet) (thickness: 1 mm).
The content of the ingredients derived from the tobacco raw material in the tobacco sheet of Example 2 was 82.3 wt%, as determined by calculating the proportion of the weight of the tobacco raw material relative to the total weight of the tobacco raw material (tobacco sample) and any externally added ingredients (guar gum, CMC, and glycerin) that had been used.

COMPARATIVE EXAMPLE

(Preparation of Tobacco Formulation and Tobacco Sheet)

300 g of the tobacco sample (ground) noted in Example 1 above and 1000 g of water were homogenized in a homogenizer (ROBOMICS, by Tokushu Kika Kogyo Co., Ltd.) to obtain a mixture. 15 g of glycerin, 15 g of pulp (particle size: 900 µm (weighted average particle size)), and 15 g of guar gum (as the binder) were added to and mixed with 1300 g of the resulting mixture to obtain a suspension (tobacco formulation). The resulting suspension was spread out on a stainless steel sheet and allowed to dry naturally at room temperature to produce a slurry sheet (tobacco sheet) (thickness: 1 mm).
The content of the ingredients derived from the tobacco raw material in the tobacco sheet of the Comparative Example was 86.9 wt%, as determined by calculating the proportion of the weight of the tobacco raw material relative to the total weight of the tobacco raw material (tobacco sample) and any externally added ingredients (glycerin, pulp, and guar gum) that had been used.

(1) Determination of Particle Size of Poorly Water-Soluble Substance

2.5 g (1 g, based on the weight of the solids) of the suspension obtained in Example 1 above (preparation of tobacco formulation and tobacco sheet) was weighed out as as a suspension sample. Portions of the slurries obtained in Example 1 and the Comparative Example above (preparation of tobacco formulation and tobacco sheet) were cut to obtain 1 g of slurry sheet samples.
40 mL of water was added per 2.5 g (1 g, based on the weight of the solids) of the suspension sample of Example 1 and per 1 g each of the slurry sheet samples of Example 1 and the Comparative Example, and the samples were then heated for 30 minutes at 80°C to obtain liquid mixtures. The resulting liquid mixtures were centrifuged for 5 minutes at 5530 G using a centrifuge (refrigerated centrifuge, by Kubota Corporation), and the supernatant was removed, giving 0.5 g portions of precipitate.
40 mL of water was added to the resulting 0.5 g portions of precipitate, and they were heated for 30 minutes at 80°C to obtain liquid mixtures. The resulting liquid mixtures were centrifuged for 5 minutes at 5530 G using a centrifuge (refrigerated centrifuge, by Kubota Corporation), and the supernatant was removed, giving 0.4 g portions of precipitate. The resulting 0.4 g portions of precipitate were treated two more times by the same processes as above (addition of water, heating, mixing, centrifugation, and removal of supernatant) to obtain 0.3 portions of precipitate.
40 mL of a 95% ethanol aqueous solution was added to the resulting 0.3 g portions of precipitate, and the ingredients were then mixed to obtain dispersions of each precipitate. The resulting dispersions were analyzed using a wet particle size analyzer (HORIBA Partica 960, HORIBA, Ltd.), and the resulting particle size (D90) values were used as the measured particle size (primary particle size) of the poorly water-soluble substance. The results are shown in Table 1.

(2) Determination of Water Content

The water content of the tobacco formulations was determined based on IR moisture analysis of the suspensions (tobacco formulation) obtained in Examples 1 and 2 above (preparation of tobacco formulation and tobacco sheet) using an IR moisture analyzer (MB45, by OHAUS). The results are shown in Table 1.

(3) Determination of Content of Poorly Water-Soluble Substance

2.5 g (1 g, based on the weight of the solids) of the suspensions obtained in Examples 1 and 2 above (preparation of tobacco formulation and tobacco sheet) were weighed out as suspension samples. 40 mL of 80°C hot water was added to 2.5 g (1 g, based on the weight of the solids) of the sample suspensions of Examples 1 and 2, the ingredients were stirred for 30 minutes, and the samples were centrifuged for 5 minutes at 5530 G using a centrifuge (refrigerated centrifuge, by Kubota Corporation). After centrifugation, the supernatant was removed, giving 0.5 g of precipitate. The resulting 0.5 g of precipitate was treated three more times by the same processes as above (addition of hot water, mixing, centrifugation, and removal of supernatant), the precipitate was recovered, the resulting precipitate was dried for 30 minutes at 80°C, and the resulting dried material was weighed. The proportion (wt%) of the weight of the resulting dry material relative to the weight of the solids (1 g) of the suspensions used above was calculated, and the resulting value was used as the content (wt%) (calculated on the basis of the solids) of the poorly water-soluble substance in the resulting suspensions. The results are shown in Table 1.
The slurry sheet is formed by removing only the water used as the medium from the suspension, and the content (wt%) (calculated on the basis of the solids) of the poorly water-soluble substance in the suspensions obtained as described above can therefore be considered to be equal to the content (wt%) of the poorly water-soluble substance in the slurry sheet.

(4) Determination of Starch Content

2.5 g (1 g, based on the weight of the solids) of the suspensions obtained in Example 1 and the Comparative Example above (preparation of tobacco formulation and tobacco sheet) were weighed out as as a suspension samples. 2.5 g (1 g, based on the weight of the solids) of the suspension samples of Example 1 and the Comparative Example above were ground into powder materials via homogenization using a homogenizer (ROBOMICS, by Tokushu Kika Kogyo Co., Ltd.). 100 mg of the resulting powder materials were weighed out and introduced into 15 mL-centrifuge tubes (SUMILON^®, by Sumitomo Bakelite Co., Ltd.), 10 mL of MilliQ water (ambient temperature) was added, and the contents were then ultrasonically extracted for 10 minutes using an ultrasonic device (BRANSONIC, Emerson Japan Co., Ltd.) to obtain liquid mixtures. The resulting liquid mixtures were centrifuged for 5 minutes at 4°C and 8,000 rpm using a centrifuge (refrigerated centrifuge, by Kubota Corporation). After centrifugation, the supernatant was removed to obtain precipitate. 7 mL of dimethylsulfoxide (DMSO) was added to the resulting precipitate, and the contents were stirred with a vortex mixer to obtain suspensions. The resulting suspensions were heated (extracted) for 5 minutes at 100°C to dissolve the starch contained in the precipitate in DMSO. The extracted suspensions were quenched with ice water, and were centrifuged for 5 minutes at 3,000 G using the centrifuge described above. After centrifugation, 5 mL of supernatant was collected and introduced into 50-mL measuring flasks. The supernatant in the measuring flasks was treated three more times by the same processes as above (extraction for 5 minutes at 100°C, quenching with ice water, centrifugation for 5 minutes at 3,000 G, and collection of 5 mL of supernatant and introduction into 50-mL measuring flasks) to obtain 20 mL of DMSO in which starch had been dissolved (while in the measuring flasks).
MilliQ water was added to the 20 mL of DMSO to bring the volume to 100 mL, the contents were stirred, and the 100 mL samples were transferred to glass test tubes. 500 µL of 5% phenol solution was introduced into the samples in the test tubes, and 2.5 mL of concentrated sulphuric acid was gradually introduced to break down the the starch in the samples into monosaccharides. The resulting solutions were then stirred in a vortex mixer, and were then allowed to stand for 20 minutes. The absorbance of the solutions that had been allowed to stand in the test tubes was determined at 490 nm using a spectrophotometer (SP-300, by OPTIMA Co., Ltd.). The absorbance was similarly analyzed using glucose that had been dissolved in 5% phenol solution as the calibration curve. The glucose concentrations were 0 µg/mL, 10 µg/mL, 20 µg/mL, 50 µg/mL, and 100 µg/mL. Based on the absorbance that had been determined and the calibration curve, the percentage of the weight (wt%) of the starch relative to the weight of the solids (1 g) of the suspension that had been used was calculated as the starch content (wt%). The results are shown in Table 1.
The slurry sheet is formed by removing only the water used as the medium from the suspension, and the content (wt%) (calculated on the basis of the solids) of the starch in the suspensions obtained as described above can therefore be considered to be equal to the content (wt%) of the starch in the slurry sheets.

[Table 1]

Table 1

	Particle size of poorly water-soluble substance (µm)		Water content (wt%)	Poorly water-soluble substance content (wt%) (calculated on basis of solids)	Starch content (wt%) (calculated on basis of solids)
	Suspension	Slurry Sheet	Suspension	Suspension	Suspension
Example 1	22.4	24.2	60	30	3.04
Example 2	-	-	60	12	-
Comparative Example	-	113.15	-	-	2.47

* Dashes in the table mean "not determined."

The results of Example 1 and Example 2 above show that the tobacco formulations of Example 1 and Example 2 can be used to produce a tobacco sheet without the external addition of pulp. When the tobacco formulations of Example 1 and Example 2 are obtained, the starch contained in the tobacco raw material is extracted via a boiling process, and a poorly water-soluble substance is obtained in the form of tobacco raw material residue. As an alternative to another poorly water-soluble substance, the resulting poorly water-soluble substance derived from the tobacco raw material enhances the formability and strength of the tobacco sheet, thus allowing a tobacco sheet to be formed without the external addition of another poorly water-soluble substance. In the tobacco formulations of Examples 1 and 2, there is no need to externally add another poorly water-soluble substance such as pulp, thus allowing that much more tobacco raw material or glycerin to be added as well as affording a greater degree of freedom in tobacco formulation and tobacco sheet design.
Also, as shown in Table 1, the particle size (µm) of the poorly water-soluble substance was determined to be very small due to the grinding and extraction treatment, at 22.4µm in the suspension and 24.2 µm in the slurry sheet of Example 1. It appears that this reduced particle size of the poorly water-soluble substance in Example 1 results in an increase in the surface area of the tobacco particles adhering to each other, allowing the strength of the slurry sheet to be enhanced.
With the tobacco formulation of the Comparative Example, on the other hand, pulp was added as the poorly water-soluble substance to produce the tobacco sheet. If no pulp were externally added to the tobacco formulation of the Comparative Example, a tobacco sheet could not be produced because the sheet configuration cannot be preserved. In the Comparative Example, the particle size of the poorly water-soluble substance derived from the tobacco raw material was large due to the absence of grinding/extraction treatment. The surface area of the tobacco particles adhering together was thus insufficient, and pulp needed to be added to improve the strength of the slurry sheet.
The results of Table 1 also show that the content of the poorly water-soluble substance in the suspension of Example 2 (12 wt%) was lower than the content of the poorly water-soluble substance in the suspension of Example 1 (30 wt %). This is attributed to the fact that the number of boiling treatments in Example 2 is higher than in Example 1, which thus allows more of a component such as starch to be extracted from the tobacco raw material, and the greater amount in turn results in that much less of the measured amount of the poorly water-soluble substance. The results of Examples 1 and 2 show that changing the conditions of the boiling treatment allows the amount of extracted components such as starch to be controlled.
The results of Table 1 furthermore confirmed that the starch content in the suspension of Example 1 was 3.04 wt%, which was higher than the starch content of 2.47 wt% in the suspension of the Comparative Example. This might be attributed to the fact that, in the suspension of Example 1, the boiling treatment resulted in a correspondingly greater release of starch in the suspension extracted from the tobacco raw material, as compared with the suspension of the Comparative Example in which no boiling treatment was carried out. When a greater amount of starch is contained in the suspension, as is the case in Example 1, the starch functions as a binder to join the poorly water-soluble substance together, thus allowing a stronger tobacco sheet to be produced.
A tobacco raw material can thus be used in the tobacco sheet of present invention to produce a tobacco sheet without the external addition of another poorly water-soluble substance raw material.

REFERENCE SIGNS LIST

10 Heating device
11 Body
12 Heater
20 Heat-not-burn smoking product
20A Smoking segment
20B Connecting portion
20C Filter portion
21 Smoking composition sheet or material derived therefrom
22 Wrapper
23 Paper tube
24 Ventilation holes
25 First segment
25a First filling layer
25b Inner plug wrapper
26 Second segment
26a Second filling layer
26b Inner plug wrapper
27 Outer plug wrapper
28 Wrapper

Claims

A tobacco formulation comprising:
(1) a poorly water-soluble substance derived from a tobacco raw material;

(2) starch extracted from said tobacco raw material or from another tobacco raw material; and

(3) a medium.
A tobacco sheet, comprising
(1') a poorly water-soluble substance derived from a tobacco raw material; and

(2') starch extracted from said tobacco raw material or from another tobacco raw material.
The tobacco sheet according to claim 2, wherein the starch is starch extracted from said tobacco raw material.
The tobacco sheet according to claim 2 or claim 3, wherein the starch is soluble starch.
The tobacco sheet according to any of claims 2 to 4, wherein the primary particle size of the poorly water-soluble substance is 100 µm or less.
The tobacco sheet according to any of claims 2 to 5, wherein the starch content in the tobacco sheet is 10 wt% or less.
The tobacco sheet according to any one of claims 2 to 6, wherein the tobacco raw material from which the poorly water-soluble substance is derived comprises leaf tobacco.
The tobacco sheet according to any of claims 2 to 7, wherein the tobacco raw material from which the poorly water-soluble substance is derived comprises an alkaloid.
The tobacco sheet according to any of claims 2 to 8, further comprising an aerosol-generating agent.
The tobacco sheet according to claim 9, wherein the aerosol-generating agent comprises glycerin, 1,2-propanediol, 1,3-propanediol, or a mixture thereof.
The tobacco sheet according to any of claims 2 to 10, further comprising glucan.
The tobacco sheet according to claim 11, wherein the glucan comprises tamarind gum, guar gum, locust bean gum, gellan gum, pullulan, or a mixture thereof.
The tobacco sheet according to any one of claims 2 to 12, wherein no pulp is included.
The tobacco sheet according to any of claims 2 to 13, which is a cast sheet.
The tobacco sheet according to any one of claims 2 to 14, which is a molded body of the tobacco formulation according to claim 1.
A tobacco filler comprising the tobacco sheet according to any of claims 2 to 15.
A smoking product comprising the tobacco filler according to claim 16.
The smoking product according to claim 17, which is a non-combustible heated smoking product.
A method for producing the tobacco formulation according to claim 1, comprising the step of heating the tobacco raw material in the medium to extract the starch.
A method for producing the tobacco sheet according to any of claims 2 to 15, comprising
a step in which the tobacco formulation is produced by the method according to claim 19, and

a step in which the tobacco formulation is spread onto a substrate and is then dried.