WO2013035505A1 - Method for preventing increase in tobacco specific nitrosamines during storage - Google Patents

Abstract

The present invention is a method for preventing an increase in tobacco specific nitrosamines (TSNA) in leaf tobacco during storage, said method being characterized by the reduction of the total amount of oxygen in contact with the leaf tobacco during storage.

Description

Methods for inhibiting the increase in tobacco-specific nitrosamines during storage.

The present invention relates to a method for suppressing an increase in tobacco-specific nitrosamine during storage.

In the dried tobacco, N′-nitrosonornicotine (NNN), 4- (N′-nitrosomethylamine) -4- (3-pyridyl) -1-butanone (NNK), N′-nitrosoanatabine There are tobacco-specific nitrosamines (hereinafter referred to as “TSNA”) represented by (NAT) and N′-nitrosoanabasin (NAB).

TSNA is basically not present in tobacco leaves immediately after harvest, but nitrite nitrogen in leaf tobacco reacts with alkaloids (such as nicotine, nornicotine, anatabine and anabasine) during the drying and storage process. Is generated by For example, during the drying period, it is known that nitric acid is reduced to nitrous acid by the action of nitrate-reducing bacteria present on the tobacco surface, and this nitrous acid reacts with alkaloids to produce TSNA. Thus, various methods for suppressing the production of TSNA during the drying period and during the storage period have been developed.

For example, as a treatment for tobacco before harvesting, Patent Document 1 describes a method for reducing the amount of TSNA produced by reducing the nicotine content by treating tobacco plants with auxin or the like. . Patent Document 2 describes a method in which the production of antioxidants is promoted by spraying abscisic acid or an analog thereof onto tobacco plants, thereby inhibiting the production of TSNA.

As a treatment for leaf tobacco after harvesting, Patent Document 3 describes a method of decomposing and reducing TSNA in tobacco tobacco by adding a metal iodate salt to tobacco tobacco.

Patent Document 4 describes a method for reducing the TSNA content of leaf tobacco by treating the tobacco with a microorganism that reduces TSNA. Patent Document 5 describes a method of reducing the nitrite content and / or nitrosamine content in leaf tobacco by treating the tobacco having a denitrification ability and reducing the nitrite content of the leaf tobacco. ing.

Of the methods for suppressing the production of TSNA during the drying period, Patent Document 6 describes that the drying method is characterized in that a cut-out groove is provided in the tobacco stem and the tobacco stem is in a standing state for 1 to 7 days. A stem drying method is described in which leaf tobacco that has been left to stand on the tobacco trunk is wilted, and then the tobacco trunk is accommodated and suspended in a drying facility such as a pipe house and dried. Further, Patent Document 7 describes a method of drying leaf tobacco without touching the leaf tobacco with exhaust gas containing nitric oxide generated from the heat exchange unit.

On the other hand, during the storage period, it is known that NOx gas generated from dry tobacco leaves reacts with alkaloids to produce TSNA. As a method for suppressing the production of TSNA during the storage period, Patent Document 8 discloses that tobacco that does not have nitrate reducing ability and exhibits growth antagonistic action against anaerobic microorganisms is treated with tobacco. A method for reducing the TSNA content in tobacco is described. Patent Document 9 describes a method of adsorbing and removing NOx gas generated from dry tobacco leaves during storage of dry tobacco leaves by using an adsorbent, thereby suppressing TSNA generation during dry tobacco storage periods. Has been.

By the way, as a method for storing leaf tobacco, in Patent Document 10, leaf tobacco is put in a breathable inner bag, and this is stored in a gas-impermeable outer bag together with an oxygen scavenger in an airtight seal, and stored. A method for killing tobacco pests is described.

Japanese Patent Gazette “Special Table 2005-522201” (published on July 28, 2005) International Publication No. WO2004 / 068973 (released on August 19, 2004) International Publication No. WO2007 / 125831 (published on November 8, 2007) International Publication No. WO2003 / 094639 (published on November 20, 2003) Japanese Patent Publication “JP 2005-27545 A” (published on February 3, 2005) Japanese Patent Publication “Japanese Patent Laid-Open No. 2006-238766” (published on September 14, 2006) US Patent Application Publication No. 2001/0000286 (published on April 26, 2001) Japanese Patent Publication “JP 2005-27544 A” (published February 3, 2005) Japanese Patent Publication “JP 2007-20515 A” (published on February 1, 2007) Japanese Patent Publication “JP-A-62-14773” (published on January 23, 1987)

In the conventional technology that requires the addition or spraying of treatment agents or microorganisms for the reduction or increase of TSNA, and the conventional technology characterized by the drying method, for the suppression of the increase in TSNA immediately after each treatment or immediately after drying, Although effective, it is ineffective in suppressing the increase in TSNA during long-term storage. Moreover, since the addition of a substance or the change of a drying method is accompanied, there exists a possibility of affecting the original flavor of leaf tobacco.

In the method of treating microorganisms with leaf tobacco, the microorganisms are mixed with water and sprayed with a sprayer or the like. In this case, under the influence of the sprayed water, there is a risk that the quality of the leaf tobacco during drying will be significantly reduced such as stuffiness and rot. Moreover, the growth of microorganisms is susceptible to temperature and humidity. However, it is difficult to control and maintain the environment of the drying facility to an environment suitable for the growth of microorganisms. Furthermore, in the spraying of microorganisms, it is necessary to proliferate the microorganisms in advance, and the spraying work is troublesome.

In the conventional technique using a NOx gas adsorbent (Patent Document 9), the NOx gas generated during storage is adsorbed and removed by enclosing a large amount of adsorbent in a sealed container, so that the burden of volume and cost is large. Further, in the case of long-term storage, the acting force of the adsorbent is weakened, and it is difficult to maintain the suppression of the increase in TSNA.

The present invention has been made in view of the above problems, and an object thereof is to provide a novel method for suppressing an increase in TSNA in leaf tobacco during storage.

TSNA during storage is generated from NOx gas and alkaloids. That is, if the amount of NOx gas increases, the amount of TSNA generated also increases. When leaf tobacco is stored in a sealed container, the container is filled with NOx gas. Therefore, storing leaf tobacco in a sealed container has been considered to be a factor that increases TSNA. However, as a result of intensive studies by the present inventors, it has been found that an increase in TSNA can be suppressed when leaf tobacco is stored in a sealed container. As a result of further studies, it was found that the increase in TSNA can be suppressed by reducing the oxygen concentration in the container or reducing the amount of atmosphere. This invention is made | formed based on the novel knowledge which concerns, and includes the following inventions.

That is, the method according to the present invention is a method for suppressing an increase in TSNA in leaf tobacco during storage, and is characterized in that the total amount of oxygen in contact with leaf tobacco during storage is reduced.

According to the present invention, an increase in TSNA in leaf tobacco during storage can be suppressed.

In one Example of this invention, it is a figure which shows the relationship between the atmosphere amount in a container, and TSNA increase amount. In another Example of this invention, it is a figure which shows the long-term change of the TSNA increase amount at the time of storing with an airtight bag. In another Example of this invention, it is a figure which shows the relationship between oxygen concentration and TSNA increase amount. It is a figure which shows the TSNA increase amount at the time of performing the low oxygen process by deaeration etc. in the further another Example of this invention. In another Example of this invention, it is a figure which shows the TSNA increase amount at the time of using adsorption agent for a deoxygenation process. In another Example of this invention, it is a figure which shows the TSNA increase amount at the time of using the low oxygen process by deaeration etc., and the deoxygenation process by a deoxidizer. In a reference example, it is a figure which shows the relationship between storage temperature and TSNA increase amount.

Hereinafter, an embodiment of a method for suppressing an increase in TSNA in leaf tobacco during storage according to the present invention will be described.

The method for suppressing an increase in TSNA in leaf tobacco during storage according to the present embodiment (hereinafter referred to as the present suppression method) is a method for suppressing an increase in TSNA in leaf tobacco during storage, A method comprising reducing the total amount of oxygen in contact with the tobacco leaves.

The time to apply this control method is during the storage period of leaf tobacco after harvesting and drying leaf tobacco. For example, as one embodiment, the present suppression method can be applied to leaf tobacco from which the middle bone has been removed after drying, but is not limited thereto. Storage is usually carried out for 1 to 3 years, but may be carried out at any time during the storage period. Especially, it is preferable to always implement this suppression method from the storage start time to the storage end time.

There are no particular limitations on the type of tobacco that is subject to this suppression method, and examples include commonly used tobacco such as yellow, Burley, native, oriental, and rusty. Among these, since Burley seeds tend to accumulate TSNA during natural drying, it is more effective to suppress further increases in TSNA during storage in Burley seeds.

TSNA that can suppress the increase by this suppression method includes N′-nitrosonornicotine (NNN), 4- (N′-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK) N′-nitrosoanatabine (NAT), N′-nitrosoanabasin (NAB), 4- (N′-nitrosomethylamino) -4- (3-pyridyl) -1-butanol (NNA), 4- ( N′-nitrosomethylamino) -1- (3-pyridyl) -1-butanol (NNAL), 4- (N′-nitrosomethylamino) -4- (3-pyridyl) -1-butanol (iso-NNAL) , And 4- (N′-nitrosomethylamino) -4- (3-pyridyl) -butanoic acid (iso-NNAC), etc., which are produced by the nitration reaction of alkaloids in tobacco. Compound is included.

In this specification, “suppressing the increase in TSNA” means reducing the TSNA content as compared with the case where no treatment for suppressing the increase in TSNA is performed during storage. In addition, there is no restriction | limiting in particular in the grade, if the content of TSNA is reducing compared with the case where no process is made. The TSNA content in leaf tobacco may be measured using a known measurement method, for example, using the CRM72 method defined by Cholesta (CORESTA: Centre de Cooperation pour les RecherchesScientifiques Relatives au Tabac) Can do.

In this specification, the “total amount of oxygen” is an amount represented by the product of “volume of the space where the tobacco is placed” and “oxygen concentration”. Here, “space where leaf tobacco is placed” refers to the space in the container when leaf tobacco is placed in the container, and the space in the storage when leaf tobacco is placed in the storage as it is. As such, it refers to the finite area surrounding the tobacco. The “oxygen concentration” refers to the amount of oxygen (O ₂ ) contained per unit volume of the space where the tobacco is placed.

That is, in this specification, “reducing the total amount of oxygen in contact with the tobacco” means (i) lowering the oxygen concentration in the space where the tobacco is placed to be lower than the oxygen concentration in the atmosphere (21%); ii) reducing the volume of the space in which the tobacco is placed, while keeping the oxygen concentration in the space in which the tobacco is placed, or (iii) reducing the oxygen concentration in the space in which the tobacco is placed; It is intended to reduce the volume of the space where tobacco is placed.

In the present suppression method, a specific method for reducing the total amount of oxygen in contact with leaf tobacco during storage includes, for example, placing leaf tobacco in an airtight container. Gas exchange is not performed between the inside and outside of the airtight container, and no new oxygen is supplied into the container. As a result, the total amount of oxygen in contact with the leaf tobacco in the container is reduced. This can be reduced as compared with the case where the container is not contained.

If the container containing the tobacco is sealed, the generated NOx gas cannot be discharged to the outside, and the amount of NOx gas in the container increases. From this point, it is considered that when the container containing the tobacco is sealed, the production of TSNA is promoted and the increase in TSNA cannot be suppressed. However, as shown in the following examples, an increase in TSNA can be suppressed by placing in an airtight container.

As long as the airtight container in this embodiment can be sealed and does not allow gas to pass, there is no particular limitation on the shape, material, and the like, and a box-shaped container, a bag-shaped container, a bottle, a can, and the like are used. be able to. In the present specification, the “airtight container” is preferably a container that can be completely sealed. However, as long as the total amount of oxygen in contact with the tobacco can be reduced, it can be used as an airtight container in this embodiment even if the sealing is not complete. When storing a large amount of tobacco, a container may be used. In addition, the case where the tobacco case is stored is not limited to the case where the airtightness can be maintained. For example, the leaf tobacco is placed in a storage case that does not have airtightness, and the chuck that can maintain the airtightness together with the storage case. It can also be covered with attached bags.

If it is in an airtight container, it suppresses the increase in TSNA compared to when it is not in the container and when it is in the container but is not airtight (ie in an open system). be able to. Therefore, although there is no restriction | limiting in particular in the volume of a container, It is preferable that the atmosphere amount in the container per weight of leaf tobacco is 50 ml / g or less, and it is more preferable that it is 40 ml / g or less.

Here, “the amount of atmosphere in the container” refers to the volume of the space (including the space between the tobacco leaves) occupied by the part other than the tobacco in the container. Specifically, it is a value obtained by subtracting [actual volume of leaf tobacco] from [volume of container]. The actual volume of leaf tobacco can be calculated by [weight of leaf tobacco (g)] / [apparent density of leaf tobacco (g / ml)]. In addition, in order to make the space in a container small, what does not have a bad influence on storage of leaf tobacco (for example, a balloon etc.) can be put. In this case, the amount of atmosphere in the container is a value obtained by further subtracting the volume of the object.

The method of reducing the atmosphere volume of the container per weight of the tobacco is not limited to simply using a container having a smaller volume, and, for example, put it in an airtight container (for example, a bag or a bottle) and deaerate it. This can reduce the amount of atmosphere in the container.

In the present specification, “degas” means to remove at least a part of the gas in the container, and when the inside of the container is kept at a negative pressure, even when the inside of the container is kept at a constant pressure. Is also included. That is, when deaeration is performed on a container such as a bag whose volume is variable, the volume of the container may change and remain in an isobaric state. On the other hand, when deaeration is performed on a container such as a bottle whose volume is unchanged, the volume of the container does not change and can be in a negative pressure state.

In the present suppression method, the method for reducing the total amount of oxygen in contact with leaf tobacco during storage may include reducing the oxygen concentration in the gas in contact with leaf tobacco.

In the present specification, “reducing the oxygen concentration” means making the oxygen concentration lower than the oxygen concentration in the atmosphere. As a method for reducing the oxygen concentration in the gas that contacts the tobacco, for example, the tobacco is brought into contact with a gas other than oxygen. Specifically, the total amount of oxygen in contact can be reduced by placing the tobacco in an atmosphere other than oxygen or an atmosphere that does not contain oxygen. Examples of gases other than oxygen include nitrogen gas, carbon dioxide gas, argon gas, helium gas, and the like, preferably nitrogen gas and carbon dioxide gas, and more preferably nitrogen gas. For example, putting tobacco in an airtight container and replacing some or all of the oxygen in the gas inside the container with a gas other than oxygen described above can be mentioned. The replacement may be performed by filling the inside of the container with a gas other than the oxygen described above after or after deaeration in an airtight container.

The oxygen concentration is preferably as low as possible, for example, preferably 10% or less, more preferably 5% or less, and most preferably 0%.

Further, as another method for reducing the oxygen concentration in the gas in contact with the tobacco, the tobacco is placed in an airtight container, and further, an adsorbent that adsorbs oxygen is placed in the container. As the adsorbent, oxygen scavenger, activated carbon, zeolite, carbon nanotube, charcoal and the like can be used. Among these, an oxygen scavenger is preferable. The amount of adsorbent that adsorbs oxygen may be appropriately determined depending on the type of adsorbent and the size of the container. It is desirable to use a quantity that can sufficiently adsorb oxygen in the container. For example, in a container having a capacity of 1 liter, an oxygen adsorbent that can adsorb about 200 ml of oxygen may be used in consideration of the oxygen concentration in the air and the volume of tobacco.

Also, as a method of reducing the total amount of oxygen that comes into contact with leaf tobacco during storage, the leaf tobacco may be placed in an airtight container (for example, a bag or bottle) and degassed.

Further, the method for reducing the total amount of oxygen that comes into contact with leaf tobacco during storage may be a method in which two or more methods described above are combined. For example, tobacco and oxygen scavenger can be placed in an airtight container and further replaced with nitrogen gas.

Furthermore, it is preferable that the storage environment is at least a low temperature. For example, it is 50 ° C. or lower, preferably 40 ° C. or lower, more preferably 25 ° C. or lower.

抑制 According to this control method, it is not necessary to perform pre-harvest processing, drying management, and spraying of processing agents and substances, so that labor can be reduced. Also, by applying this control method to leaf tobacco during storage, not during drying where the flavor of leaf tobacco is formed, leaf tobacco during storage without any influence on the original flavor of leaf tobacco The increase in TSNA can be suppressed. Therefore, the storage method of the leaf tobacco including this suppression method, and the leaf tobacco stored by this storage method are also included in the category of the present invention. In the leaf tobacco storage method, at least the present suppression method may be implemented, and a known technique for suppressing an increase in TSNA content may be further applied.

Further, in the present suppression method, when the tobacco leaves are put in an airtight container, there are further advantages that pests can be controlled and moisture absorption and drying can be suppressed.

As described above, the method according to the present invention is a method for suppressing an increase in TSNA in stored tobacco and is characterized by reducing the total amount of oxygen in contact with the stored tobacco. is there.

In the method according to the present invention, it is preferable that the above-mentioned leaf tobacco is put in an airtight container and the amount of atmosphere in the container per weight of the leaf tobacco is 50 ml / g or less.

In the method according to the present invention, it is preferable that the leaf tobacco is placed in an airtight container, and the amount of atmosphere in the container per weight of the leaf tobacco is 40 ml / g or less.

In the method according to the present invention, it is preferable to reduce the amount of atmosphere in the container by putting the leaf tobacco in an airtight container and degassing the container.

In the method according to the present invention, it is preferable to put the above-mentioned tobacco in an airtight container and reduce the oxygen concentration in the atmosphere in the container.

In the method according to the present invention, it is preferable to place an adsorbent that adsorbs oxygen in the container.

In the method according to the present invention, the adsorbent is preferably an oxygen scavenger.

In the method according to the present invention, it is preferable to place the tobacco leaf under a gas other than oxygen.

In the method according to the present invention, the gas other than oxygen is preferably nitrogen gas or carbon dioxide gas.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. EXAMPLES Hereinafter, although an Example and a reference example demonstrate this invention further in detail, this invention is not limited to these examples.

<Example 1>
In order to investigate the relationship between the amount of atmosphere in the container enclosing the leaf tobacco and the TSNA content in the encapsulated leaf tobacco, the following test was performed.

(Method)
Leaf tobacco, a Burley species, was dried. The dried leaf tobacco was chopped to a size of about 1 cm. The tobacco leaves were dried naturally using a pipe house.

The tobacco leaves prepared as described above were sealed in airtight containers with different capacities (manufacturer: Butterfly Plastic Industry Co., Ltd., trade name: tight box, material: body-polypropylene, lid-AS resin, capacity: 260 ml, 590 ml (1200 ml, 2700 ml, 5600 ml) were sealed with air in 30 g portions and treated at 70 ° C. and 50% RH for 24 hours. Further, as a control, the same treatment as described above was performed without putting the tobacco tobacco into an airtight container (open system). After the treatment, each tobacco cut was collected from an airtight container and ground, and then the contents of NNN, NNK, NAT, and NAB (per weight of tobacco) were measured. The total value of these four types was added to obtain the TSNA content (per weight of tobacco). The amount of TSNA increase was calculated based on the TSNA content in the tobacco leaf before treatment at 70 ° C. In addition, by exposing the tobacco tobacco to 70 ° C., the amount of TSNA that increases during storage can be grasped. The TSNA content in the tobacco leaf before treatment at 70 ° C. was 2.5 μg / g.

(Quantification of TSNA)
Analysis of TSNA was performed in accordance with Cholesta CRM72.

That is, 0.5 g of each powder sample was weighed into a 50 mL sampling tube, 20 mL of an extract (0.1 M ammonium acetate solution) was added, and the mixture was shaken at room temperature for 30 minutes. The obtained crude extract was diluted 10 times with an extract (0.1 M ammonium acetate solution) and filtered using a filter (Millipore filter 0.20 μm), and this was used as a sample for TSNA quantification.

Each component of TSNA in the obtained sample was analyzed using LC-MS / MS.

Table 1 below shows the amount of atmosphere in the container (bag) under normal atmospheric conditions and the amount of atmosphere per cigarette weight. The amount of atmosphere per weight of tobacco cut was calculated as (volume of container (ml)) − (weight of tobacco cut (g)) / (apparent density of tobacco tobacco (g / ml)). In the leaf tobacco (Burley variety) used this time, the apparent density was 0.7 g / ml and the water content was 11%.

(result)
The results are shown in FIG. As shown in FIG. 1 (a), when leaf tobacco is encapsulated in an airtight container, the amount of TSNA increase in leaf tobacco after treatment is small compared to control (open system). It became clear. Also, as the volume of the container decreases (> 1200 ml), the amount of increase in TSNA after processing decreases, and it is clear that the increase in TSNA content is effectively suppressed when the volume of the container is 1200 ml or less. became.

FIG. 1B shows the result shown in FIG. 1A converted into an atmospheric amount. As shown in FIG. 1 (b), it was shown that an increase in TSNA content was effectively suppressed, particularly when the amount of atmosphere per cigarette weight was 50 ml / g or less.

<Example 2>
In order to examine long-term changes in the TSNA content in leaf tobacco when leaf tobacco was stored in a sealed bag, the following storage test was conducted.

(Method)
130 kg of leaf tobacco dried in the same manner as in Example 1 was placed in a case (62 cm × 110 cm × 77 cm, the top plate and the bottom plate are made of wooden plates, and the sides are made of thick cardboard). In the treatment area, the case containing the tobacco was further covered with a bag with a chuck, and the chuck was closed and stored in an airtight state in a storage room. In the normal ward, it was stored in the storage room as it was without being covered with bags. The temperature of the storage room during the implementation period of this example was 23.5 ° C. to 28.5 ° C. The humidity of the storage room was 51% to 61% RH. In order to examine the change in TSNA content during the storage period, 300 g of leaf tobacco was collected and ground after a predetermined storage period (after 1, 2, 4, 6, 10, and 18 months). The TSNA content was measured by the same method as in Example 1, and the TSNA increase amount was calculated. In addition, the start of storage in a present Example is the middle of June. The TSNA content in the leaf tobacco before storage was 2.5 μg / g.

(result)
The results are shown in FIG. As shown in FIG. 2, it was revealed that the TSNA increase amount in the leaf tobacco was small in the treated group at any time after storage for 1 month or more, compared to the normal group. From this, it was shown that the increase in TSNA is suppressed by covering the case with a bag with a chuck and storing it in an airtight state. Moreover, it was shown that the difference from the normal section becomes clear when stored for more than one month.

<Example 3>
In order to investigate the relationship between the oxygen concentration around the tobacco leaf and the TSNA content in the tobacco leaf, the following test was conducted.

(Method)
Into an air bag (1000 ml, made of vinyl fluoride resin (PVF)), 10 g of tobacco tobacco prepared by the same method as in Example 1 is added, and the oxygen concentration inside the air bag is 5%, 10%, 21%. Or it adjusted to 100%. The oxygen concentration of 21% is almost the same oxygen concentration as the atmosphere and is a control. These were then treated at 70 ° C. for 24 hours. Regarding humidity, a saturated solution of potassium carbonate was used to adjust the humidity to an equilibrium state (43% at 20 ° C.). After the treatment, each tobacco leaf was collected and ground, and then the TSNA content was measured in the same manner as in Example 1 to calculate the TSNA increase. The TSNA content in the tobacco tobacco before treatment at 70 ° C. was 2.5 μg / g.

(result)
The results are shown in FIG. As shown in FIG. 3, it was revealed that the lower the oxygen concentration around the tobacco leaf, the smaller the TSNA increase in the tobacco leaf after treatment. From this, it was shown that the increase in TSNA is suppressed as the oxygen concentration around the tobacco tobacco is lower.

<Example 4>
In order to examine the TSNA content in leaf tobacco when low oxygen treatment by deaeration or low oxygen treatment by gas replacement was performed, the following test was performed.

(Method)
10 g of tobacco tobacco prepared by the same method as in Example 1 is put in the same air collection bag (1000 ml) as in Example 3, and any of the following treatments (i) to (iii) is performed inside the air collection bag: Performed: (i) deaeration treatment, (ii) about 750 ml of 100% nitrogen gas after deaeration treatment, or (iii) about 750 ml of 100% carbon dioxide gas after deaeration treatment. Other processing methods were the same as those in Example 3. After treating at 70 ° C. for 24 hours, each tobacco cut was collected and ground, and then the TSNA content was measured by the same method as in Example 1 to calculate the TSNA increase. The TSNA content in the tobacco tobacco before treatment at 70 ° C. was 2.5 μg / g.

(result)
The results are shown in FIG. As shown in FIG. 4, in any of the above treatments (i) to (iii), the increase in TSNA after the treatment was 7.5 μg / g or less. All values are smaller than the TSNA increase amount when the oxygen concentration is 21% in the test in Example 3. From this, it was shown that the increase in TSNA content in the tobacco tobacco was suppressed by performing deaeration treatment or replacement with nitrogen gas or carbon dioxide gas.

<Example 5>
In order to investigate the TSNA content in the tobacco when deoxygenation was performed using an oxygen adsorbent, the following test was performed.

(Method)
In an air collection bag (1000 ml) similar to that in Example 3, 10 g of tobacco tobacco prepared in the same manner as in Example 1 and an oxygen adsorbent were sealed. As an oxygen adsorbent, an iron-based self-supporting oxygen absorber (product name: AGELESS, product specification number: Z-100PK, manufactured by Mitsubishi Gas Chemical Co., Ltd.) or activated carbon (product name: coconut shell activated carbon (granule)), Wako Pure Chemical Industries, Ltd.) was used. As for the oxygen scavenger, 5 oxygen scavengers (oxygen adsorption amount: 200 ml / piece) are used per air bag. For the activated carbon, 1/10 amount (1 g) of the activated carbon of cigarette chopped weight is used. It was used. Other processing methods were the same as those in Example 3. After treating at 70 ° C. for 24 hours, each tobacco cut was collected and ground, and then the TSNA content was measured by the same method as in Example 1 to calculate the TSNA increase. The TSNA content in the tobacco leaf before treatment was 2.5 μg / g.

(result)
The results are shown in FIG. As shown in FIG. 5, when an oxygen scavenger was used as the oxygen adsorbent, the TSNA increase after the treatment was about 2.5 μg / g. When activated carbon was used as the oxygen adsorbent, the TSNA increase after the treatment was about 8.5 μg / g. All the values are lower than the TSNA increase when the oxygen concentration is 21% in the test in Example 3. From this, it was shown that the increase in the TSNA content in the tobacco tobacco was suppressed by placing the tobacco tobacco in an airtight container together with an oxygen scavenger or activated carbon.

Also, the amount of increase in TSNA after the treatment at 70 ° C. was smaller when the oxygen scavenger was used compared with the activated carbon. From this, it was shown that the increase in TSNA content was suppressed more by using the oxygen scavenger than by using activated carbon.

<Example 6>
In order to examine the TSNA content when a combination of low oxygen treatment by degassing or the like and deoxygenation treatment with a deoxidant was used, the following test was conducted.

(Method)
10 g of tobacco tobacco prepared by the same method as in Example 1 and an iron-based self-supporting oxygen scavenger (product name: AGELESS, product specification number: Z) -100 PK (manufactured by Mitsubishi Gas Chemical Co., Inc.) was added and degassed or 100% nitrogen gas was sealed in an approximately 750 ml container after degassing. Other processing methods were the same as those in Examples 3 to 5. After treating at 70 ° C. for 24 hours, each tobacco cut was collected and ground, and then the TSNA content was measured by the same method as in Example 1 to calculate the TSNA increase.

(result)
The results are shown in FIG. As shown in FIG. 6, the TSNA increase after the treatment was around 2.5 μg / g in any case. All values are smaller than the TSNA increase amount when the oxygen concentration is 21% in the test in Example 3. From this, it was shown that the TSNA increase in the tobacco tobacco was suppressed by using a combination of low oxygen treatment by degassing or gas replacement and deoxygenation treatment with a deoxidant.

Further, when compared with the results of Example 4, the combination of the low oxygen treatment by degassing or gas replacement and the deoxygenation treatment by the oxygen scavenger is more than the case of performing only the low oxygen treatment by degassing or gas replacement. The increase in TSNA in the tobacco leaf after treatment at 70 ° C. for 24 hours was small. From this, it was shown that, in addition to the low oxygen treatment by deaeration or gas replacement, the increase in TSNA is further suppressed by performing a deoxygenation treatment with a deoxygenating agent. Further, in the treatment in this example that combines the low oxygen treatment by deaeration and the deoxygenation treatment by the oxygen scavenger, the amount of increase in TSNA becomes smaller compared to the deoxygenation treatment by the oxygen scavenger in Example 5. , T-test (two-sided risk rate 5%) showed that the difference was significant.

<Reference example>
In order to investigate the relationship between the storage temperature of leaf tobacco and the TSNA content in leaf tobacco, the following test was conducted.

(Method)
50 g of tobacco tobacco prepared by the same method as in Example 1 is placed on a flat plate, and using a temperature and humidity controller, under the conditions of 10 ° C., 25 ° C., 40 ° C., 55 ° C. or 70 ° C. and 50% RH. Stored for a predetermined number of days. In the treatment under each temperature condition, the tobacco leaf was collected and pulverized at a plurality of time points during the treatment period, and then the TSNA content was measured by the same method as in Example 1 to calculate the TSNA increase amount.

(result)
The results are shown in FIG. As shown in FIG. 7, it was found that the higher the temperature during storage, the greater the increase in TSNA content in the tobacco.

In the storage that stores the tobacco, air conditioning may not be managed. In this case, the temperature of the storage may reach 40 ° C. Therefore, this suppression method can be applied suitably also in the general storage condition of leaf tobacco.

The present invention can suppress an increase in TSNA in leaf tobacco during storage.

Claims (9)

1. A method for suppressing an increase in tobacco-specific nitrosamines in leaf tobacco during storage,
   A method of reducing the total amount of oxygen in contact with leaf tobacco during storage.
2. The method according to claim 1, wherein the leaf tobacco is placed in an airtight container, and the amount of atmosphere in the container per weight of the leaf tobacco is 50 ml / g or less.
3. The method according to claim 2, wherein the leaf tobacco is put in an airtight container, and the amount of atmosphere in the container per weight of the leaf tobacco is 40 ml / g or less.
4. The method according to claim 1, wherein the amount of atmosphere in the container is reduced by putting the leaf tobacco in an airtight container and degassing the container.
5. The method according to claim 1, wherein the tobacco leaf is placed in an airtight container to reduce the oxygen concentration in the atmosphere in the container.
6. The method according to claim 5, wherein an adsorbent that adsorbs oxygen is placed in the container.
7. The method according to claim 6, wherein the adsorbent is an oxygen scavenger.
8. The method according to any one of claims 5 to 7, wherein the leaf tobacco is placed under a gas other than oxygen.
9. The method according to claim 8, wherein the gas other than oxygen is nitrogen gas or carbon dioxide gas.

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