JP2003024423A - Odor blocking agent for blocking odor of alkyl pyrazine compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an odor blocking agent for blocking the odor of an alkyl pyrazine compound with a mechanism different from a conventional masking. SOLUTION: This odor blocking agent comprises, as an effective component, a functional pyrazine compound having alkyl groups substituted in the 2nd and 5th positions of a pyrazine ring, and an electron-donating functional group having a Van der Waals volume of 34Å<3> or less substituted in the 3rd-position.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an odor blocking agent, and more particularly to an odor blocking agent that blocks the odor of an alkylpyrazine compound.

[0002]

2. Description of the Related Art Conventionally, in order to prevent the unpleasant odor from being sensed by the olfactory sense, it is a comfortable odor, but the unpleasant odor is masked with a stronger odor than the unpleasant odor.
Is being done.

[0003]

According to this masking method, the unpleasant odor is not perceived by the olfactory sense, but the odor masking the unpleasant odor is strongly perceived.

Generally speaking, the object of the present invention is to provide an odor blocking agent which, unlike conventional masking, prevents unpleasant odors from being sensed by the olfactory sense.

[0005]

In order to achieve the above object, the inventors of the present invention competitively inhibit an unpleasant odor at a receptor portion of a specific odor that senses an unpleasant odor, and thereby produce an unpleasant odor compound. In the course of researching odor blocking agents that function to prevent the uptake of
We have found that the odor of alkylpyrazine compounds can be blocked by certain functional pyrazine compounds, thus completing the invention.

That is, the present invention provides an odor blocking agent for blocking the odor of an alkylpyrazine compound, which has the following formula (I):

[Chemical 3] (Here, R ₁ is an alkyl group, R ₂ is an electron-donating functional group having a van der Waals volume of 32Å ³ or less,
R ₃ provides an odor blocking agent, which comprises a functional pyrazine compound represented by an alkyl group) as an active ingredient.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

Alkylpyrazine compounds are flavor components produced by roasting peanuts, but when the roasting time is too long, the amount increases and as an off-flavor that reduces the flavor of peanuts. To work. Alkylpyrazine compounds are also contained in milk powder in small amounts, resulting in poor taste. Such an alkylpyrazine compound has the following formula (II)

[Chemical 4] (Here, R ₁₁ , R ₁₂ and R ₁₃ are each independently
Alkyl group or alkenyl group having 1 to 3 carbon atoms). A representative alkylpyrazine compound is 2-ethyl-3,5-dimethylpyrazine.

According to the present invention, the odor of such an alkylpyrazine compound is determined by the substitution of an alkyl group at each of the 2- and 5-positions of the pyrazine ring and the electron-donating functional group having a predetermined van der Waals volume at the 3-position. Is blocked by a substituted functional pyrazine compound. The functional pyrazine compound of the present invention has the following formula (I):

[Chemical 5] Indicated by. In Formula (I), R ₁ represents an alkyl group, R ₂ represents an electron-donating functional group having a van der Waals volume of 32Å ³ or less, and R ₃ represents an alkyl group. Here, R ₁ is preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group. R ₂ is particularly preferably a hydroxyl group, a methoxy group or a halogen atom. Also, R
₃ is preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group. Examples of particularly preferred functional pyrazine compounds of the present invention include 2,5-dimethyl-3-chloropyrazine and 2,5-
Dimethyl-3-hydroxypyrazine and 2,5-dimethyl-3-methoxypyrazine. These functional pyrazine compounds are known per se. In addition, 2,5-dimethyl-3-hydroxypyrazine and 2,5-dimethyl-3-methoxypyrazine are 2,5-dimethyl-3-
It can also be synthesized from chloropyrazine.

The functional pyrazine compounds of the present invention are believed to be recognized by receptors that are identical or similar in structure to those that recognize the unpleasant odorous compound alkylpyrazine. Therefore, by using more than the alkylpyrazine, the functional pyrazine compound of the present invention blocks the receptor and blocks (blocks) the uptake of the alkylpyrazine compound into the receptor. Since the functional pyrazine compound of the present invention has a weak odor by itself, it is not perceived as a strong odor even when used in a large amount.

The functional pyrazine compound of the present invention can be used as it is or in a state of being carried on a carrier such as paper, fiber, capsule, liquid base material, gel base material, solid base material, mist base material and the like. it can.

As the liquid base material, water; alcohols such as methanol and ethanol; glycols such as ethylene glycol and propylene glycol; citric acid esters such as trimethyl citrate and triethyl citrate; polyoxyethylene sorbitan monooleate. Examples thereof include nonionic surfactants such as polyoxyethylene sorbitan monostearate; anionic surfactants such as sodium polyoxylauryl ether phosphate.

As the gel-like base material, gel agents extracted from various plants, animals, algae, microorganisms and the like such as carrageenan, duragan gum, tragacanth gum, agar, gelatin and pectin; gels such as sodium stearate and 12-sodium stearate. Examples thereof include metal soaps used as agents; those formed from water-soluble organic polymers such as polyvinyl alcohol and cellulose derivatives.

Examples of the solid substrate include powders or granular molded products of silica gel, alumina, activated carbon and the like, which have physical adsorption ability and have a large specific surface area.

Examples of the mist-like base material are nonionic surfactants such as polyoxyethylene sorbitan monooleate and polyoxyethylene sorbitan monostearate; anionic surfactants such as sodium polyoxylauryl ether phosphate. Is exemplified.

As described above, in the odor blocking agent of the present invention containing the functional pyrazine compound as an active ingredient, the concentration of the functional pyrazine compound of the present invention in the air is higher than the concentration of the odor compound, preferably 10 times or more, And, more preferably, it can be used so as to have a concentration lower than the threshold value of the functional pyrazine compound of the present invention (that is, the minimum concentration at which the functional pyrazine compound of the present invention itself smells).

[0017]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Synthesis Example 1 2,5-Dimethyl-3-chloropyrazine (1.00 g;
A methanol solution of 7.01 mmol) and a methanol solution of sodium methoxide (0.38 g; 7.01 mmol) were cooled to 0 ° C. and then mixed. The resulting mixture was heated under reflux for 4 hours. The reaction mixture was suction filtered to remove precipitated salts, and the filtrate was concentrated with an evaporator. The concentrated residue was extracted with ethylene oxide and dried over sodium sulfate. After concentrating the dried extract with an evaporator, the target fraction was collected by silica gel column chromatography (developing solvent: chloroform). The obtained fraction was dried in vacuum to obtain 2,5-dimethyl-3-methoxypyrazine as a pale yellow liquid. Yield 61.2 mg (0.449 mmol).

Synthesis Example 2 2,5-Dimethyl-3-chloropyrazine (5.00 g;
After adding a 20 wt% potassium hydroxide aqueous solution to (35.1 mmol), the mixture was heated under reflux for 18 hours. 2N Hydrochloric acid was added to the reaction mixture to make it neutral, and suction filtration was performed to remove precipitated salts. The filtrate was extracted with chloroform, and the extract was dried over magnesium sulfate. After concentrating the dried extract with an evaporator, a target fraction was collected by silica gel column chromatography (developing solvent: ethyl acetate). The obtained fraction was vacuum dried to obtain 2,5-dimethyl-
3-Hydroxypyrazine was obtained as white needle crystals.
Yield 2.99 g (24.5 mmol).

Example 1 In order to confirm the effect of the odor blocking agent of the present invention,
The following experiment was conducted.

(A) Measurement of odor threshold of 2-ethyl-3,5-dimethylpyrazine <Method> Two glass bottles A and B having the same volume are prepared.
In one glass bottle A, a control sample piece in which triethyl citrate (TEC) was dropped as a control on a filter paper piece, and a test sample in which a TEC solution of an odorous compound 2-ethyl-3,5-dimethylpyrazine was dropped on a filter paper piece Put a piece and stopper tightly. Into the other glass bottle B, two control sample pieces to which TEC was dropped are put and tightly stoppered.

The five panelists (three non-smoking women and two smoking men) compare the smell inside the glass bottle A with the smell inside the glass bottle B and select the one with the stronger smell. By changing the concentration of 2-ethyl-3,5-dimethylpyrazine in the test sample piece, 2-ethyl-3,5 when the intensity of odor can be discriminated
-The concentration at the boundary between the concentration of dimethylpyrazine and the concentration of 2-ethyl-3,5-dimethylpyrazine when the intensity of odor cannot be discriminated is determined as the odor threshold of 2-ethyl-3,5-dimethylpyrazine. . In addition, this measurement is performed twice by five panelists (on different days), and the odor threshold is defined by the geometric mean value of 10 times in total.

<Results> The concentration of 2-ethyl-3,5-dimethylpyrazine was adjusted to 0, 0.01, 0.002, 0.00.
3, 0.004, 0.005, 0.006, 0.00
The odor threshold of 2-ethyl-3,5-dimethylpyrazine was 0.00 when the odor threshold was determined by the above-mentioned measurement method while changing it to 8, 0.009, 0.010 (μg / L).
It was determined to be 2 μg / L.

(B) Measurement of odor blocking effect of odor blocking agent against 2-ethyl-3,5-dimethylpyrazine odor <Method> Two glass bottles A and B having the same volume are prepared.
On the other hand, in a glass bottle A, a test piece (2,5-dimethyl-3-methoxypyrazine, 2,5 -Dimethyl-3-hydroxypyrazine or 2,5-dimethyl-3-chloropyrazine)
Put the sample piece to which the TEC solution of 1 was dropped and tightly stopper. In the other glass bottle B, a sample piece in which TEC was dropped on a filter paper piece and a sample piece in which a TEC solution of a test compound was dropped on a filter paper were placed and tightly closed.

The five panelists (three non-smoking women and two smoking men) sniff the smell in the glass bottle A and the smell in the glass bottle B, and select the one with a stronger smell. By changing the concentration of the test compound, 2-ethyl-
2-Ethyl-3,5-when the intensity of odor can be discriminated by changing the concentration of 3,5-dimethylpyrazine and 2-ethyl-3,5 when the intensity of odor cannot be discriminated from the concentration of odor The concentration at the boundary with the concentration of dimethylpyrazine is determined as the odor threshold of 2-ethyl-3,5-dimethylpyrazine. In addition, this measurement is performed twice by five panelists (on different days), and the odor threshold is defined by the geometric mean value of 10 times in total.

<Results> 2-Ethyl-in each concentration of 2,5-dimethyl-3-methoxypyrazine (methoxy form)
The odor threshold of 3,5-dimethylpyrazine is shown in FIG.
-Dimethyl-3-hydroxypyrazine (hydroxy form)
2 shows the odor threshold of 2-ethyl-3,5-dimethylpyrazine at each concentration of 2,5-dimethyl-3-chloropyrazine (chloro body) at each concentration.
The odor thresholds of 3,5-dimethylpyrazine are shown in FIG. 3, respectively.

From this result, the functional pyrazine compound of the present invention raises the odor threshold of 2-ethyl-3,5-dimethylpyrazine (ie, the odor of 2-ethyl-3,5-dimethylpyrazine is detected. 2-ethyl-3,5
-Increase the minimum concentration of dimethylpyrazine). Further, from these results, the functional pyrazine compound of the present invention shares the receptor with the alkylpyrazine compound, and acts to prevent the alkylpyrazine compound from being taken up by the receptor by blocking the receptor. I understand.

Example 2 The following experiment was conducted to examine whether or not the functional pyrazine compound of the present invention can reduce the odor intensity of the alkylpyrazine compound itself.

<Method> Two glass bottles A and B having the same volume
To prepare. On the other hand, in the glass bottle A, a piece of filter paper was added to the TEC of the odorant compound (2-ethyl-3,5-dimethylpyrazine)
Solution (concentration 0.158μg / L or 0.0158μg
/ L) was added dropwise to the test piece (2,5
-Dimethyl-3-chloropyrazine) and a sample piece to which a TEC solution has been added dropwise, and the container is sealed. In the other glass bottle B, a TEC solution (concentration: 0.1
(58 μg / L or 0.0158 μg / L) and the sample piece with TEC added to the filter paper are put and sealed. The concentration of the test compound is changed for each concentration of the odorous compound.

The eight panelists compare the smell inside the glass bottle A with the smell inside the glass bottle B, and select and report the one with the stronger smell.

<Results> As shown in Table 1 below, when the concentration of the test compound was changed, the number of panelists who responded that the odorous compounds had a stronger odor is shown in the same table.

[0032]

[Table 1]

From these results, it can be seen that the functional pyrazine compound of the present invention can reduce the strength of the alkylpyrazine compound itself.

[0034]

As described in detail above, according to the present invention,
Provided is an odor blocking agent that blocks the odor of an alkylpyrazine compound by a mechanism different from conventional masking.

[Brief description of drawings]

FIG. 1 is a diagram showing odor thresholds of 2-ethyl-3,5-dimethylpyrazine at various concentrations of 2,5-dimethyl-3-methoxypyrazine (methoxy form).

FIG. 2 shows 2-ethyl-3,5 at various concentrations of 2,5-dimethyl-3-hydroxypyrazine (hydroxy form).
-Figure showing the odor threshold of dimethylpyrazine.

FIG. 3 is a diagram showing odor thresholds of 2-ethyl-3,5-dimethylpyrazine at various concentrations of 2,5-dimethyl-3-chloropyrazine (chloro form).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Shikata             6-2 Umegaoka, Aoba-ku, Yokohama-shi, Kanagawa Japan             Tobacco Industry Co., Ltd. Tobacco Central Research Institute F-term (reference) 4C080 AA06 BB02 CC07 HH01 JJ01                       KK08 LL02 MM18

Claims (3)

[Claims] 1. An odor blocking agent for blocking the odor of an alkylpyrazine compound, which is represented by the following formula (I): (Here, R ₁ is an alkyl group, R ₂ is an electron-donating functional group having a van der Waals volume of 32Å ³ or less,
R ₃ is an odor blocking agent characterized by containing a functional pyrazine compound represented by an alkyl group) as an active ingredient. 2. An alkylpyrazine compound is represented by the following formula (I
I) [Chemical formula 2] (Here, R ₁₁ , R ₁₂ and R ₁₃ are each independently
The odor blocking agent according to claim 1, which is represented by an alkyl group or an alkenyl group having 1 to 3 carbon atoms. 3. In the formula (I), R ₁ is a methyl group, R ₂ is a hydroxyl group, a methoxy group or a halogen atom, and R ₃ is a methyl group. The odor blocking agent according to 1 or 2.