The present invention relates to a tobacco material manufacturing method and a tobacco material manufactured by the manufacturing method.

Methods for treating tobacco leaves in order to change the flavor of the tobacco leaves have been examined. For example, in a known method, burley tobacco leaves are pressurized and dried (Patent Document 1). Patent Document 1 indicates that a pressurization condition is set to 25 kPa to 700 kPa and that the moisture content of tobacco leaves is kept more than 10%.

A technique is also known in which a mixture of tobacco leaves with the moisture content thereof adjusted at least to 15% are subjected to heat treatment (at least 250°F) under conditions sufficient to generate a fragrance or a fragrant component (substantially at the atmospheric pressure) (Patent Document 2). Patent Document 2 indicates that the heat treatment is performed for 10 minutes at a temperature ranging from 121°C to 177°C (examples).

A method is also known in which tobacco strips are loaded on a belt conveyor and conveyed so as to pass through a dryer to be subjected to drying treatment (Patent Document 3). Patent Document 3 indicates that, in this method, tobacco leaves with a moisture content of approximately 30% are dried so as to finally reduce the moisture content approximately to 5% and that the temperature for the drying ranges from 93°C to 118°C.

Furthermore, a rotary dryer configured to dry tobacco leaves, tobacco strips, and shredded tobacco leaves is known (Patent Document 4). Patent Document 4 does not disclose specific conditions for drying tobacco leaves, nor the moisture content of the tobacco leaves.

• [Patent Document 1] Japanese Translation of PCT Application Publication No. 2003-509077
• [Patent Document 2] U.S. Patent No. 6298858
• [Patent Document 3] Japanese Patent No. 3441079
• [Patent Document 4] W/O 2007/045606

Patent Document 1, Patent Document 2, and Patent Document 3 all describe a step of heating tobacco leaves while keeping the moisture thereof at a given value or larger.

Patent Document 1 indicates that filing power for tobacco strips is improved by keeping the moisture content of tobacco leaves at more than 10% during heating and also keeping the moisture content of the tobacco leaves at 10% or more after drying. Patent Document 2 indicates that tobacco leaves before drying have a moisture content of at least 15% in order to generate a sufficient amount of fragrant components.

On the other hand, Patent Document 3 indicates that the chemical composition and flavor of tobacco after treatment are affected unless the moisture content of tobacco leaves is kept at a given value or larger.

As described above, the techniques described in the above-described Patent Documents perform a drying treatment on tobacco leaves for various purposes but all involve drying the tobacco leaves with the moisture content thereof adjustably kept high before drying. In particular, Patent Document 1 and Patent Document 3 indicate that it is important to prevent the moisture content from decreasing as much as possible even during the drying step.

None of the above-described Patent Documents describes a case where a drying treatment is performed under the condition that tobacco leaves have a very low moisture content. None of the above-described Patent Documents describes a relation between the drying treatment under conditions that tobacco leaves have a very low moisture content and a change in the filling capacity or flavor of the tobacco leaves.

An object of the present invention is to provide a manufacturing method that enables filling capacity of tobacco leaves to be enhanced and that allows a tobacco material with a flavor thereof changed to be obtained.

As a result of earnest studies, the inventor has reached the present invention by finding that the above-described object can be accomplished by including a step of heating a tobacco material with a moisture content of 2.5 wt% or less under conditions that the tobacco leaf material has a product temperature of 100°C to 200°C.

That is, the present invention is as described below.

1. [1] A tobacco material manufacturing method including a step of heating a tobacco leaf material with a water content of 2.5 wt% or less under conditions that the tobacco leaf material has a product temperature of 100°C to 200°C.
2. [2] The manufacturing method set forth in [1], further including, before the heating step, a step of reducing the water content of the tobacco leaf material to 2.5 wt% or less.
3. [3] The manufacturing method set forth in [1] or [2], in which the water content of the tobacco leaf material subjected to the drying step is 10 wt% to 40 wt%.
4. [4] The manufacturing method set forth in any one of [1] to [3], in which the tobacco leaf material contains laminae, stems, or a mixture of the laminae and the stems having a shred width of 0.1 mm to 2.0 mm.
5. [5] A tobacco material produced by the manufacturing method set forth in any one of [1] to [4].
6. [6] A tobacco product in which the tobacco material set forth in [5] is used.
7. [7] A cigarette in which the tobacco material set forth in [5] is used.
8. [8] A smokeless tobacco product in which the tobacco material set forth in [5] is used.

The present invention can provide a manufacturing method for manufacturing a tobacco material with filling capacity thereof enhanced and with a flavor thereof changed.

• [Fig. 1]
  Fig. 1 is a diagram illustrating an example of an aspect of a tobacco material manufacturing method of the present invention.
• [Fig. 2]
  Fig. 2 is a diagram illustrating a relation between filling capacity of a tobacco material obtained through the manufacturing method of the present invention and a product temperature on heating.
• [Fig. 3]
  Fig. 3 is a diagram illustrating a relation between the filling capacity of the tobacco material obtained through the manufacturing method of the present invention and a moisture content of the tobacco material on heating at a predetermined product temperature.
• [Fig. 4]
  Fig. 4 is a diagram depicting an example of a heating dryer that can be used in the manufacturing method of the present invention.

The present invention will be described in detail with reference to an embodiment, illustrative objects, and the like. However, the present invention is not limited to the embodiment, illustrative objects, and the like described below, and the embodiment, illustrative articles, and the like may be changed without departing from the spirits of the present invention.

A tobacco material manufacturing method of the present invention includes a step of heating a tobacco leaf material with a water content of 2.5 wt% or less at a product temperature of 100°C to 200°C.

The tobacco material with a water content of 2.5 wt% or less can be obtained, for example, by the following two methods.

An aspect of a first method may include a step of placing a tobacco leaf material with a water content of, for example, 10 wt% to 40 wt% in the same heating apparatus as that used in a subsequent heating step (production heating) and heating the tobacco leaf material within a temperature range from normal temperature to 100°C to 200°C (product temperature) as illustrated in Fig. 1 (a) (preliminary heating or drying).

A second method is a method including a separate drying process of drying a tobacco leaf material with a water content of, for example, 10 wt% to 40 wt% using a heating apparatus that is the same as or different from a heating apparatus used in the subsequent heating step (production heating) as illustrated in Fig. 1 (b). A heating temperature and the heating apparatus in this case are not particularly limited. Any heating temperature and any heating apparatus may be used as long as the heating temperature and the heating apparatus allow the water content of the tobacco leaf material can be reduced to 2.5 wt% or less.

The water content of the tobacco leaf material can be measured by the following measuring method.

1. 1. An amount of tobacco leaf material weighing 1 g to 2 g is placed in a sample container formed of glass. The whole sample container is weighed.
2. 2. The sample container is placed in a rotary dryer (manufactured by Matsuyama Industry Co., Ltd.; M-104AT) and dried while being rotated. In this case, the rotary dryer is preheated to 100°C.
3. 3. The sample container is dried at 100°C for one hour. Then, the sample container is taken out of the rotary drier and placed and cooled in a desiccator.
4. 4. After cooling, the sample container is weighed.
5. 5. The moisture content is calculated in accordance with the following expression: $$\mathrm{Moisture\; content}=\left(\mathrm{W}\mathrm{1}-\mathrm{W}\mathrm{2}\right)/\left(\mathrm{W}\mathrm{1}-\mathrm{W}\mathrm{0}\right)*\mathrm{100}$$
   • W0: the empty weight of the sample container
   • W1: the weight of the undried sample and the sample container
   • W2: the weight of the dried sample and the sample container

The tobacco leaf material with a moisture content of 2.5 wt% or less is heated so as to have a product temperature of 100°C to 200°C. Examples of a heating method include a method of bringing the tobacco leaf material into contact with hot steam (200°C or higher) or hot air or a method of bringing the tobacco leaf material into contact with a heating container heated to 200°C or higher.

The method of bringing the tobacco leaf material into contact with hot steam and the method of bringing the tobacco leaf material into contact with the heated heating container may be performed singularly or concurrently.

As means for generating hot steam, well-known means, for example, a heated steam generator (for example, manufactured by Fuji Electric Thermo Systems Co., Ltd.; model: IHSS-20B) may be used.

An example of the heated heating container may be a drum-like boiler wall heating dryer. In an aspect, a set temperature for the heating container (setting of a boiler wall temperature) may be set to 200°C to 330°C and is preferably set approximately to 300°C.

When the heating is performed under conditions that a tobacco leaf material with a water content of 2.5 wt% or less has a product temperature of 100°C or higher, the filling capacity of tobacco leaves is enhanced and the flavor of the tobacco leaves is significantly changed. On the other hand, when the heating is performed under conditions that a tobacco leaf material with a water content of 2.5 wt% or less has a product temperature of 200°C or lower, the tobacco leaves can be prevented from being carbonized. A preferable condition for more preferable product temperature is 120° C or higher and 200° C or lower.

Furthermore, a condition for the time needed for the above-described heating step varies according to the amount of a heated tobacco leaf material, the size of the apparatus, and the like. However, in order to enable the filling capacity of the tobacco leaf material to be sufficiently enhanced and to allow the flavor of the tobacco leaf material to be substantially changed, the tobacco leaf material is preferably heated for two seconds or longer so as to set the product temperature of the tobacco leaf material to 100°C to 200°C. In order to enhance the filling capacity of the tobacco leaf material, the tobacco leaf material is preferably heated for 30 seconds or longer and particularly preferably 120 seconds or longer so as to set the product temperature of the tobacco leaf material to 100°C to 200°C. It is important to avoid inconveniences such as crushing and carbonization of the tobacco leaf material resulting from excessive heating of the tobacco leaf material in a state where the product temperature exceeds 200°C. In a state where the product temperature is 200°C or lower can be maintained, an upper limit on the heating time can be set as needed.

The time for the heating step (production heating) means the time during which the tobacco leaf material has a water content of 2.5 wt% or less and a product temperature of 100°C to 200°C.

The manufacturing method of the present invention may include, besides the above-described preliminary heating (a state where the water content is more than 2.5 wt% and the product temperature ranges from normal temperature to 100°C or higher) and the above-described production heating, heating in which the tobacco leaf material has a water content of 2.5 wt% or less and a product temperature of lower than 100°C (for example, a heating state based on residual heat after the heating) and a state during the production heating where the product temperature exceeds 200°C if this state lasts only a short time.

The term "flavor of tobacco" as used in the present invention refers to the level of roast feeling or the like. The tobacco material resulting from the manufacturing method of the present invention has an enhanced roast feeling. Moreover, when stems are contained in the tobacco leaf material, the smell of the stem can be reduced.

The term "product temperature of the tobacco leaf material" refers to the temperature measured by the following method.

The tobacco leaf material heated by the heating means is poured in a Dewar vessel in which a thermocouple is inserted, within two seconds and is brought into sufficient contact with the thermocouple. Then, the Dewar vessel is corked and left stationary. The maximum temperature displayed in this state is determined to be the product temperature.

As the form of the tobacco leaf material used for the tobacco material manufacturing method of the present invention, a shredded tobacco leaf material and an unshredded tobacco leaf material may be used. Furthermore, the tobacco leaf material may be either a mesophyll portion (lamina) or a vein portion (stem) into which tobacco leaves are divided and may include a tobacco stem portion that is not included in the tobacco leaf portions. An example of the tobacco leaf material may be tobacco leaves shredded so as to have a shred width of 0.1 mm to 2.0 mm. The shred width may be determined as needed according to the application of the tobacco material, for example, cigarettes or oral-cavity tobacco. Available types of tobacco leaves include, for example, major types such as flue-cured tobacco leaves, barley tobacco leaves, traditional tobacco leaves, and oriental tobacco leaves, and fermented tobacco leaves resulting from the above-described tobacco leaves.

The term "shred width" as used in the present invention refers to a value set for shredding of material leaf tobacco using a tobacco shredder. The shredding of tobacco leaves is an operation of shredding material leaf tobacco into elongate fibers with a constant width. The resultant fibers are referred to as shred tobacco. An apparatus that performs the shredding is referred to as a shredder, and a rotary shredder and a clipping shredder are commonly used. The shred width is a value set as the width of the material leaf tobacco with which the tobacco is shredded using the above-described apparatus.

The tobacco material manufacturing method of the present invention may include well-known steps in addition to the above-described heating step. For example, the method may include, after the heating step, a step of cooling the tobacco material and a step needed to produce various tobacco products described below, for example, cigarettes or smokeless tobacco, as needed.

An example of the step needed to produce various tobacco products may be a step of adding an additive such as a flavoring agent to the tobacco material obtained. Furthermore, a humidification step may be included as needed.

Aspects of the tobacco material obtained using the manufacturing method of the present invention may include the use of the tobacco material for applications of various tobacco products as described below.

A well-known manufacturing method for cigarettes may be used without any particular limitation except for the use of the tobacco material obtained using the manufacturing method of the present invention. The cigarette may or may not include a filter.

When the tobacco material obtained using the manufacturing method of the present invention is used for cigarettes, a rich-smoke feeling is given.

In an aspect, the proportion of the tobacco material obtained using the manufacturing method of the present invention and contained in the tobacco material of the cigarette may be 5 wt% to 100 wt%.

An example of smokeless tobacco is snus. A well-known snus manufacturing method may be used. In this case, the snus is obtained by filling a packing material formed of a raw material such as a nonwoven cloth with the tobacco material produced by the above-described manufacturing method, using a well-known method. For example, the snus is obtained by filling the packing material with the tobacco material with the amount thereof adjusted and sealing the packing material using means such as heat seal.

Any packing material may be used without any particular limitation. A cellulose-based nonwoven cloth or the like is preferably used.

When the smokeless tobacco product is gum, the gum is obtained by mixing a well-known gum base with the tobacco material obtained by the manufacturing method of the present invention, using a well-known method. Chewing tobacco, snuffs, and compressed tobacco can also be obtained using a well-known method except for the use of tobacco material obtained by the manufacturing method of the present invention.

In an aspect, the proportion of the tobacco material obtained using the manufacturing method of the present invention and contained in the smokeless tobacco material may be 5 wt% to 100 wt%.

Examples of tobacco products other than cigarettes and smokeless tobacco include hand-rolled tobacco produced by users by rolling shredded tobacco leaves in paper, hookah (pneumatic water pipe), cigars, and kiseru (Japanese smoking pipe). Each of these tobacco products can be manufactured using a well-known manufacturing method for hand-rolled tobacco or hookah except for the use of tobacco material obtained by the manufacturing method of the present invention.

The present invention will further be described with reference to examples. However, the present invention is not limited to the examples described below as long as the spirits of the present invention are not departed from.

A tobacco leaf material with a water content of 12 wt% (stems shredded into fibers with a shred width of 0.2 mm) was fed into a cylinder-shaped heating dryer, which was then heated so as to increase the temperature starting with normal temperature (25°C). The heating was performed by carrying out boiler wall heating using the cylinder-shaped heating dryer heated to 300°C and bringing the tobacco leaf material into contact with heating steam at 320°C.

The heating dryer used in the example is of a type illustrated in Fig. 4. A cylinder 1 is has a cylindrical shape with internal dimensions including a diameter of 400 mm and a longitudinal length of 1900 mm and rotates at 4 rpm. The cylinder 1 is inclined such that a material inlet position is located higher than a material outlet position. The inclination angle was 3° with respect to the horizontal direction.

The tobacco material was fed into the cylinder 1, which had an exhaust duct 4 and internal blades 10, through a material inlet portion 2 via a rotary valve 3.

The cylinder 1 was heated with superheated steam produced using a heater 6 and a superheated steam generator 7.

The tobacco leaf material was conveyed by rotation and inclination of the cylinder 1 and taken out through a material outlet portion 9.

The heated steam generator manufactured by Fuji Electric Co., Ltd. (former Fuji Electric Thermo Systems Co., Ltd.); model: IHSS-20B) was used.

The relation between the heating time and the product temperature of the tobacco material is as illustrated in Table 1.

Treatment time described in Table 1 indicates a continuous time from the start of the heating. Furthermore, heating time for which the tobacco leaf material has a product temperature of 100°C or higher is also illustrated. Cylinder temperature Treatment time Time for which the tobacco leaf material has a product temperature of 100°C or higher Product tem perature Moisture Bulkiness °C sec sec °C %_w.b. cc/g Untreated 25 11.8 5.5 53 - 85 6.4 5.3 83 3 106 2.9 5.5 300 113 33 122 1.6 7.3 128 48 134 1.3 8.1 143 63 144 1.2 9.7 203 123 181 1.2 12.5

A method for measuring the filling capacity of the tobacco material obtained using the manufacturing method of the present invention is as described below.

1. 1. Leave a measurement sample stationary in advance in an environment at a temperature of 22°C and a humidity of 60%_R.H. for 72 hours or longer.
2. 2. The sample is sufficiently immingled.
3. 3. An amount of the sample weighing 8 g to 10 g is extracted.
4. 4. The sample is placed in the cylinder, which is then set in a filling capacity measuring instrument (manufactured by Borgward; DD-60A). Then, measurement is started. A loading time is set to 30 seconds.
5. 5. Thirty seconds later, a displayed value (the height of the sample) is read.
6. 6. The filling capacity is calculated in accordance with the following expression. $$\mathtt{Filling\; capacity}=\left(\mathtt{A}*\mathtt{h}\right)/\mathtt{W}*\mathtt{0.1}$$
   • A. Cylinder bottom area
   • h: Sample height (displayed value)
   • W: Measured sample weight

A method for measuring the product temperature of the tobacco leaf material in the example is as described below.

1. 1. At an outlet of the cylinder, collect the tobacco leaf material using a stainless steel shovel.
2. 2. The sample is poured into the Dewar vessel (manufactured by Thermos; Thermocut D-500) into which a thermocouple (manufactured by Hayashi Denko Co., Ltd.) is inserted, within two seconds after the collection. The sample is pushed with a rod to bring the sample into sufficient contact with the thermocouple.
3. 3. The Dewar vessel is corked and left stationary. The displayed maximum temperature is determined to be the tobacco product temperature.

The results indicated in Table 1 described above are summarized in Fig. 2 and Fig. 3. As seen in Fig. 2, the filling capacity of the tobacco leaf material obtained is enhanced by inclusion of heating performed under conditions that the tobacco leaf material has a product temperature of 100°C or higher. Furthermore, the filling capacity is enhanced by inclusion of heating (at a product temperature of 100°C or higher) performed with only a small amount of moisture contained in the tobacco leaf material (Fig. 3).

The tobacco material obtained using the tobacco material manufacturing method of the present invention has significantly enhanced filling capacity. Furthermore, the tobacco material obtained using the tobacco material manufacturing method of the present invention has a substantially changed flavor. Specifically, when used as cigarettes, the tobacco material obtained using the tobacco material manufacturing method of the present invention gives an enhanced roast feeling. In addition, the tobacco material obtained using the tobacco material manufacturing method of the present invention has a reduced smell of the stems.

The tobacco material obtained using the tobacco material manufacturing method of the present invention has significantly enhanced filling capacity and a substantially changed flavor. Such a tobacco material can be preferably used as a material for various tobacco products.

1

Cylinder

2

Material inlet portion

3

Rotary valve

4

Exhaust duct

5

Damper

6

Heater

7

Superheated steam generator

8

Valve

9

Material outlet portion

10

Blade