JP6600473B2 - Screening method for foot odor inhibitor - Google Patents

Description

  The present invention relates to an indicator for determining foot odor, a method for determining foot odor using the indicator, a method for evaluating a deodorant using the indicator, and a screening method.

Foot odor (unpleasant odor of the foot) is generated by decomposition of organic substances such as sebum, protein (keratin), and sweat by bacteria that propagate in shoes. Foot odor occurs when the foot is surrounded by the footwear and sweats. Since the foot has more sweat glands than the rest of the body, it sweats excessively and the sweat produced cannot evaporate due to the foot being surrounded by the footwear. Therefore, foot odors continuously evaporate and give off odors, which also adhere to socks and shoes.
Patent Documents 1 and 2 describe that the main causative substance of the foot odor is considered to be isovaleric acid, and that isovaleric acid is mainly produced by enzymatic conversion of L-leucine. ing.

For isovaleric aldehyde, which is a related substance of isovaleric acid, no reports related to foot odor have ever been made. Odors other than foot odor are reported in Patent Documents 3 and 4 as follows.
In Patent Document 3, methanethiol, propanethiol, dimethylsulfide, dimethyldisulfide, trimethylamine, diacetyl, acetoin, and 3-methylbutanal (isovaleric aldehyde) are components having a high contribution to menstrual odor or physiological odor. It is described that it is.
In Patent Document 4, as a result of analyzing components of odor generated when a nonaqueous skin external product is contaminated with microorganisms, isovaleric acid, isovaleraldehyde (isovaleric aldehyde), acetoin, acetic acid, butyric acid, etc. are greatly increased. It is described that it had increased.

JP2003-24422 Special table 2009-508478 JP2007-198829 JP 2014-150758 A

  With isovaleric acid, which is known as a causative agent of foot odor, the intensity of foot odor cannot be accurately evaluated even if isovaleric acid is used as an index. Therefore, a method for more objectively determining the intensity of foot odor has been desired. Accordingly, an object of the present invention is to provide a method for objectively determining foot odor and an indicator for foot odor determination used in the method. Moreover, the subject of this invention is providing the evaluation method of the deodorant agent which can objectively and accurately evaluate the performance of a deodorant agent by simple operation using the determination method. Furthermore, the subject of this invention is providing the screening method of the foot odor inhibitor which can screen a foot odor inhibitor efficiently by simple operation using the evaluation method.

  The present inventors diligently studied a method for objectively evaluating the intensity of foot odor, and surprisingly, the intensity of foot odor strongly correlates with the amount of isovaleric aldehyde, not the amount of isovaleric acid aldehyde. I found. In particular, a weak foot odor may give off an unpleasant foot odor despite the absence of isovaleric acid. It was found that even in such a weak foot odor situation, isovaleric aldehyde was generated, and even a weak foot odor could be evaluated by the amount of isovaleric aldehyde. The present invention is based on such knowledge. Specifically, the present invention is as follows.

[1] An indicator for determining foot odor containing isovaleric aldehyde.
[2] A foot odor determination method using the foot odor determination indicator according to [1].
[3] A sample present on the skin of the foot is collected, the amount of isovaleric aldehyde contained in the obtained sample is measured, and the intensity of foot odor is determined based on the amount of the isovaleric aldehyde. [2 ] The foot odor determination method of description.
[4] A deodorant agent for collecting a sample present at an application site of the deodorant agent, measuring the amount of isovaleric aldehyde contained in the sample, and evaluating the performance of the deodorant agent based on the amount of isovaleric aldehyde. Evaluation method.

[5] A screening method for a foot odor inhibitor for suppressing the generation of foot odor caused by isovaleric aldehyde,
(1) culturing a microorganism capable of producing isovaleric aldehyde in a medium containing a test substance and L-leucine,
(2) The test substance suppresses the production of isovaleric aldehyde by measuring the viable count of the microorganism and / or the amount of isovaleric aldehyde in the culture obtained in step (1). And (3) a screening method for a foot odor inhibitor, comprising the step of selecting, in the step (2), a test substance that suppresses the formation of isovaleric aldehyde as a foot odor inhibitor.
[6] The method for screening a foot odor inhibitor according to [5], wherein the microorganism is at least one selected from the group consisting of Staphylococcus.aureus, Staphylococcus.epidermidis and Corynebacterium.minutissimum.

  The foot odor can be objectively evaluated in a wide range from a weak foot odor to a strong foot odor by the foot odor determination index agent and the foot odor determination method of the present invention. By enabling the evaluation of weak foot odors, it becomes possible to predict future amplification of foot odors. Further, the deodorant agent evaluation method of the present invention makes it possible to objectively and accurately evaluate the deodorant effect of the foot odor of the deodorant agent and the performance of the deodorant agent with a simple operation. In addition, the foot odor inhibitor screening method of the present invention enables efficient screening of foot odor inhibitors with a simple operation.

6 is a graph showing the relationship between the intensity of foot odor of 10 subjects and the amount of isovaleric aldehyde in Example 1. FIG. 4 is a graph showing the relationship between the intensity of foot odor and the amount of isovaleric acid of 10 subjects in Example 1.

1. Foot odor determination indicator agent The foot odor determination indicator agent of the present invention comprises isovaleric aldehyde. The indicator for determining foot odor according to the present invention usually comprises an isovaleric aldehyde, but in order to improve its handleability, it is dissolved in a solvent such as water, methanol, ethanol, ether, isopropanol, dichloromethane, propylene glycol or the like. It can also be used after diluting. Moreover, additives such as stabilizers, bactericides, antibacterial agents, surfactants, antioxidants, fragrances, plant extracts and the like can be added as necessary. The solvent used when evaluating the strength of foot odor is not particularly limited, but, for example, propylene glycol can be used to evaluate the strength of foot odor more accurately because it is a non-volatile and non-volatile solvent. Is excellent.
As shown in Example 1, the intensity of foot odor strongly correlates with the amount of isovaleric aldehyde. Therefore, by using isovaleric aldehyde as an index, foot odor can be objectively evaluated in a wide range from weak foot odor to strong foot odor.
Therefore, an indicator for foot odor determination comprising the isovaleric aldehyde of the present invention is an objective determination of foot odor, evaluation of deodorizing effect or deodorizing effect of foot odor, evaluation of deodorant agent, screening of foot odor inhibitor Etc. are useful.

2. Foot odor determination method The foot odor intensity can be determined using the foot odor determination indicator of the present invention.
The foot odor determination method of the present invention includes, for example, collecting a sample present on the skin of the foot, measuring the amount of isovaleric aldehyde contained in the obtained sample, and determining the foot odor according to the amount of the isovaleric aldehyde. It is carried out by determining the intensity of.
In the foot odor judging method of the present invention, since the foot odor is judged using the amount of the indicator for foot odor judgment as an indicator of foot odor, the strength of the foot odor of the subject can be objectively and accurately determined by a simple operation. Can be determined.

Collection of the sample present on the skin of the foot is, for example,
(A) collecting headspace gas from the skin of the subject's foot;
(B) bringing a test piece into contact with the skin of a subject's foot and extracting a sample attached to the test piece;
(C) Extracting a sample attached to a sock worn by a subject for a certain period, and (d) contacting a solvent with the skin of a subject's foot and extracting the sample present on the skin with the solvent, etc. Can do.
Examples of the test piece include a cotton sheet, a cellulose sheet, a polyethylene sheet, a polyethylene terephthalate sheet, and the like, but the present invention is not limited to such examples.
Examples of sample collection include the methods (a) to (d), but the present invention is not limited to such examples. In addition, any one of the collection methods (a) to (d) may be used, or a sample may be collected by combining several methods. In terms of simplicity, a method using a sample attached to the test pieces (b) and (c) is preferable.

Examples of the method for measuring the amount of isovaleric aldehyde include gas chromatography-mass spectrometry, gas chromatograph-hydrogen flame ion detection method, gas chromatograph-electron capture detection method, high-speed liquid chromatograph-ultraviolet visible spectroscopy, high-speed spectroscopy. Examples of the method include a liquid chromatograph-mass spectrometry method, a detection method using a semiconductor sensor, and a gas chromatograph-mass spectrometry method is preferable. For example, in the gas chromatograph-mass spectrometry, the amount of isovaleric aldehyde can be calculated using the peak height or peak area value of isovaleric aldehyde in the chromatogram.
In the case of sensory evaluation of foot odor, “no foot odor” when the average score is less than 0.5, “weak foot odor” when the average score is 0.5 to less than 2, the average score In the case of 2 or more and less than 3.5, it can be judged that “foot odor is moderate”, and in the case of an average score of 3.5 or more, “foot odor is strong”.

3. Method for evaluating deodorant agent The method for evaluating the deodorant agent of the present invention is to collect a sample present at the application site of the deodorant agent, measure the amount of isovaleric aldehyde contained in the sample, and determine the amount of isovaleric aldehyde. It is carried out by evaluating the performance of the deodorant agent by the amount.
That is, since the deodorant agent evaluation method of the present invention evaluates the performance of the deodorant agent based on the amount of isovaleric acid aldehyde using the foot odor determination indicator of the present invention, it is objective and simple. A deodorant agent can be evaluated accurately and accurately.
In the present specification, the “deodorant agent” includes both a deodorant agent applied directly to the skin of a foot and a deodorant agent applied to an object to which foot odors such as socks and shoes adhere. In addition, examples of the application site of the deodorant agent include foot skin, socks, and shoes.

As the application amount of the deodorant agent, it is preferable to test a plurality of adaptation amounts centering on an amount that will be effective as a deodorant agent.
The contact time of the deodorant agent to the application site varies depending on the type of application site, the type of deodorant agent, the amount of deodorant agent used, the amount of active ingredient contained in the deodorant agent, etc., for example, 1 to 72 hours, more Preferably 3-24 hours etc. are mentioned.
Collection of the sample present at the application site of the deodorant agent is, for example,
(A) collecting the headspace gas at the application site of the deodorant;
(B) bringing a test piece into contact with the application site of the deodorant agent and extracting a substance adhering to the test piece; and (c) adding a solvent directly to the application site of the deodorant agent and presenting the substance at the application site. This can be done by extracting, for example.

The method for measuring the amount of isovaleric aldehyde contained in the sample present at the application site of the deodorant agent can be performed in the same manner as the method for measuring the amount of isovaleric aldehyde in the foot odor determination method.
In the deodorant evaluation method of the present invention, the amount of isovaleric aldehyde contained in the sample collected from the skin before application of the deodorant and the isovaleric aldehyde contained in the sample present at the application site of the deodorant. The performance of the deodorant agent can be evaluated based on a difference from the amount of the deodorant. For example, when the amount of the indicator for determining foot odor is reduced by the deodorant agent, it can be determined that the deodorant agent has a deodorizing effect and / or a deodorizing effect on the foot odor. Moreover, the performance of a deodorant agent can be evaluated by comparing the application site | part of a deodorand agent, and a non-application site | part instead of the comparison before and behind application of a deodorant agent as mentioned above. For example, if a deodorant is applied to one foot and a deodorant agent is not applied to the other foot, the deodorant may vary depending on the amount of isovaleric aldehyde contained in the sample collected from each foot. The performance of the agent can be evaluated.

4). Screening method for foot odor inhibitor Screening method for foot odor inhibitor for suppressing the generation of foot odor caused by isovaleric aldehyde of the present invention,
(1) culturing a microorganism capable of producing isovaleric aldehyde in a medium containing a test substance and L-leucine,
(2) Whether the test substance suppresses the production of isovaleric aldehyde by measuring the viable count of the microorganism and / or the amount of isovaleric aldehyde in the culture obtained in step (1) (3) In step (2), the step (2) includes a step of selecting a test substance that suppresses the production of isovaleric aldehyde as a foot odor inhibitor.

In step (1), the microorganism is cultured in a medium containing a test substance and L-leucine to obtain a culture (culture A).
As described in Example 2, the present inventors have found that isovaleric aldehyde is produced by culturing skin resident microorganisms that may be present in foot skin in a medium containing L-leucine. It was. That is, it has been clarified that isovaleric aldehyde is produced by the action of skin resident microorganisms from L-leucine produced by hydrolysis of proteins present in the skin of the skin by microorganisms. Therefore, step (1) completely reflects the situation where foot odor occurs, and if the amount of isovaleric aldehyde decreases in step (1) due to the presence of the test substance, the test is performed. It can be determined that the substance has an effect as a foot odor inhibitor.

  The microorganism may be any microorganism that has the ability to produce isovaleric aldehyde, and examples thereof include skin resident microorganisms, soil microorganisms, intestinal resident microorganisms, and microorganisms used in fermented foods. As the microorganism, a skin resident microorganism is preferable from the viewpoint of screening a foot odor inhibitor more suitable for suppressing foot odor. Examples of skin resident microorganisms include Staphylococcus.epidermidis, Staphylococcus.warneri A, Staphylococcus.warneri B, Staphylococcus.caprae B, Staphylococcus.haemolyticus, Staphylococcus.capitis A, Staphylococlin. Staphylococcus.delphini, Staphylococcus.aureus, Staphylococcus.hominis, Staphylococcus.xylosus, Staphylococcus.hyicus, Staphylococcus.cohnii, Corynebacterium.minutissimum, Corynebacterium.xerosis, Corynebacterium.tenuis, Micrococcus, etc.

Examples of test substances include substances that inhibit conversion at any stage of the conversion pathway from L-leucine to isovaleric aldehyde, those that decompose isovaleric aldehyde, and those that change the structure of isovaleric aldehyde And those that absorb or adsorb isovaleric aldehyde.
As the application amount of the test substance, it is preferable to test a plurality of adaptation amounts mainly on the amount that would be effective as a foot odor suppressor.
The content of L-leucine in the medium is, for example, 0.01 to 5% by weight, preferably 0.1 to 2% by weight, from the viewpoint of reproducing the conditions when actual foot odor is generated. .

As a medium to be used, a medium usually used for culturing the microorganism can be used. Examples of the medium component to be added include yeast extract, phosphoric acid, magnesium sulfate, sodium chloride, ammonium chloride, manganese chloride, iron chloride, calcium chloride and the like.
The culture time of the microorganism varies depending on the type of microorganism, the type of medium, etc., but from the viewpoint of sufficiently securing the time required for isovaleric aldehyde to be produced from L-leucine by the microorganism, for example, 1 to 72 hours. , Preferably 3-24 hours are mentioned.
Although the culture | cultivation temperature of the said microorganisms changes with kinds etc. of microorganisms, it is 20-50 degreeC from a viewpoint of growing microorganisms favorably, Preferably it is 30-40 degreeC.

In step (2), the test substance is isovaleric acid by measuring the viable count of the microorganism and / or the amount of isovaleric aldehyde in the culture (cultured product A) obtained in step (1). Determine whether to suppress the formation of aldehyde.
The method for measuring the number of viable microorganisms in the culture is not particularly limited. In the present invention, for example, the colony is applied to the agar medium and the number of colonies generated after culturing for a predetermined time is measured. Examples thereof include a counting method and a method of measuring the number of the microorganisms in the culture A by microscopic observation.
The method for measuring the amount of isovaleric aldehyde in the culture can be carried out in the same manner as the method for measuring the amount of isovaleric aldehyde in the foot odor determination method.

In step (2), in order to determine whether the test substance suppresses the production of isovaleric aldehyde, for example, the operation of step (1) is performed without including the test substance, and the culture (culture Preparation B)
(A) comparing the number of living microorganisms in the culture B with the number of living microorganisms in the culture A; and / or (b) the amount of isovaleric aldehyde contained in the culture B and the culture Comparing the amount of isovaleric aldehyde contained in product A;
Etc.
in this case,
(A1) The number of living microorganisms in the culture A is less than the number of living microorganisms in the culture B, and / or (b1) the amount of isovaleric aldehyde contained in the culture A is in the culture B. When satisfy | filling that it is less than the quantity of the isovaleric aldehyde contained, it can be determined that a test substance is a substance which suppresses the production | generation of isovaleric aldehyde.

In step (3), the test substance that suppresses the production of isovaleric aldehyde in step (2) is selected as a foot odor inhibitor.
In the method for screening a foot odor inhibitor of the present invention, a test substance that suppresses the production of isovaleric aldehyde is controlled by the viable count of the microorganism and / or the amount of isovaleric aldehyde produced by the microorganism. Select as an agent. Therefore, the foot odor inhibitor screening method of the present invention can evaluate the foot odor inhibitor objectively and accurately with a simple operation, compared with the case where the foot odor inhibitor is selected by sensory evaluation.

EXAMPLES Hereinafter, although an Example and a test example demonstrate this invention further in detail, this invention is not limited to these at all.
Evaluation of foot odor intensity, sampling from the foot, and analysis of the amount of isovaleric acid and isovaleric aldehyde were performed as follows.

Evaluation method of foot odor intensity Three panelists evaluated the foot odor intensity on the soles and fingers (socks and test pieces) of the foot using the following evaluation criteria. An average value was calculated from the numerical values of the obtained evaluation results, and was used as the intensity of foot odor.
〔Evaluation criteria〕
0 point: not smelling 1 point: faintly smelling 2 points: weakly smelling 3 points: clearly smelling 4 points: smelling slightly strong 5 points: smelling very strongly

Sampling method from the foot The subject wears the specified socks (washed, 100% cotton) and shoes, and is left for a certain time (6 hours). After leaving, fold a 2cm x 8cm test piece (100% cotton) between the thumb and forefinger, between the forefinger and middle finger, and between the middle and ring fingers, and then place the tape so that it does not come off. Wear rolls, socks and shoes. Further, after 2 hours, socks and test pieces are collected and subjected to sensory evaluation (olfaction).

Method for Analyzing Amount of Isovaleric Acid and Isovaleric Aldehyde A sample (test piece) obtained from the foot was inserted into a headspace vial, and the vaporized components were subjected to headspace-gas chromatography-mass spectrometry (HSS-GC- MS) was used under the following conditions to obtain the peak height (or peak area) of isovaleric acid and isovaleric aldehyde.
[GC-MS analysis conditions]
Model: Headspace-gas chromatograph-mass spectrometer (HSS-GC-MS) manufactured by Agilent Technologies
HSS: 7697A
GC: 7890B
MS: 5977A
Column: GL Science InertCap Pure Wax 60m, 0.25mmI. D. , 0.25 μm
Carrier gas: He
[Test conditions]
<Head space conditions>
Loop size: 3mL
Oven temperature: 45 ° C
Loop temperature: 75 ° C
Transfer line temperature: 100 ° C
Vial equilibration: 10 minutes Injection time: 1 minute <GC conditions>
Temperature: 40 ° C (2 minutes) ⇒ Temperature rise (3 ° C / min) ⇒ 180 ° C ⇒ Temperature rise (10 ° C / min) ⇒ 220 ° C
Inlet: 200 ° C
Split ratio 10: 1
Average linear velocity: 28 cm / sec <MS conditions>
Ionization method: Electron ionization method (EI)

[Quantitative determination of isovaleric aldehyde]
Based on the peak height (or peak area) of isovaleric aldehyde obtained from the above analysis results, the quantitative value (ppm) of isovaleric aldehyde was determined as follows.
A propylene glycol solution of isovaleric aldehyde of known concentration was prepared and added to a headspace vial as a standard sample. The sample and standard sample were tested by HSS-GC-MS under the above conditions, and the peak height (or peak area) of the sample and standard sample was determined.
Amount of isovaleric aldehyde (ppm)
= Standard sample concentration (ppm) x Sample peak height (or peak area) / Standard sample peak height (or peak area)
In Example 2, the quantitative value was determined based on the peak height of isovaleric aldehyde, and in Example 3, the quantitative value was determined based on the peak area of isovaleric aldehyde.

Example 1
Relationship between the intensity of foot odor and the amount of isovaleric aldehyde and isovaleric acid According to the method for evaluating the intensity of foot odor, sampling from the foot, and the method for analyzing the amount of isovaleric acid and isovaleric aldehyde, subject 10 The name foot odor was evaluated and analyzed. The results of the evaluation and analysis are summarized in FIG. 1 and FIG. In FIG. 1, 10 subjects are arranged on the horizontal axis, the “foot odor intensity” of each subject is plotted with ●, and the “peak height of isovaleric aldehyde” of each subject is plotted with ■. ing. In FIG. 2, 10 subjects are arranged on the horizontal axis, the “foot odor intensity” of each subject is plotted with ●, and the “peak height of isovaleric acid” of each subject is plotted with ■ on the vertical axis. Yes.
As can be seen from FIG. 2, isovaleric acid is not observed particularly where the foot odor intensity is low, and cannot be an indicator of the foot odor intensity. On the other hand, as can be seen from FIG. 1, the amount of isovaleric aldehyde shows a strong correlation with the intensity of foot odor in a wide range from where the intensity of foot odor is weak to where it is strong.
From the above, it can be seen that isovaleric aldehyde can be used as an excellent indicator for determining foot odor indicating the strength of foot odor.

Example 2
Production of Isovaleric Aldehyde by Various Microorganisms An experiment was conducted to determine whether isovaleric aldehyde is produced in the presence or absence of L-leucine using a skin resident microorganism that may be present in the skin of the foot. The microorganisms used are Staphylococcus.aureus, Staphylococcus.epidermidis and Corynebacterium.minutissimum.
Prepare using 1% by weight leucine-containing physiological saline so that the bacterial concentration is 1 × 10 ⁸ (CFU / mL). The test substance was added to 1% by weight. The culture was placed in a headspace vial, sealed, mixed well, and then statically cultured at 36 ° C. for 6 hours.

The gas vaporized from the obtained culture broth was analyzed by the following analysis method, and the amount of isovaleric aldehyde produced was measured. The results are shown in Table 1 below.

When L-leucine was not added to the medium, isovaleric aldehyde was not measured in the medium of any microorganism. On the other hand, when 1% by weight of L-leucine was added to the medium, isovaleric aldehyde was produced in three microorganisms, Staphylococcus.aureus, Staphylococcus.epidermidis and Corynebacterium.minutissimum.
From this test result, isovaleric aldehyde, an indicator for determining foot odor, is produced from L-leucine by microorganisms that propagate on the skin surface of the foot, such as Staphylococcus.aureus, Staphylococcus.epidermidis and Corynebacterium.minutissimum. I understand. L-leucine is produced by hydrolyzing a protein present in the skin of the skin by microorganisms.
From this test result, foot odor that inhibits the production of isovaleric aldehyde, an indicator for determining foot odor, by using microorganisms that propagate on the skin surface of the foot, such as Staphylococcus aureus, Staphylococcus epidermidis and Corynebacterium minutissimum. It is understood that inhibitors can be screened.

Example 3
Evaluation of Deodorant Agent A deodorant agent (medicinal mentholatum reflair toe cream: Rohto Pharmaceutical Co., Ltd.) was applied to the subject's foot. Then, the designated socks (washed, 100% cotton) and shoes were put on and left for a certain time (6 hours). After leaving, fold a 2cm x 8cm test piece (100% cotton) between the thumb and forefinger, between the forefinger and middle finger, and between the middle and ring fingers, and then place the tape so that it does not come off. I wore rolls, socks and shoes. After another 2 hours, socks and test pieces were collected, the collected test pieces were inserted into a headspace analysis vial, and the amount (A) of isovaleric aldehyde adhering to the test pieces was analyzed.
Further, the same procedure as described above was performed without applying a deodorant agent to the subject's feet, and the amount (B) of isovaleric aldehyde adhering to the test piece worn by the subject was analyzed.
The amount of isovaleric aldehyde (A) was compared with the amount of isovaleric aldehyde (B) to examine whether the deodorant agent decreased the indicator for foot odor determination. When the index agent for foot odor determination was decreased by the deodorant, the deodorant was evaluated as having a deodorizing effect and / or a deodorizing effect.

In test subject No.1, the right foot with deodorant applied has a foot odor intensity of 1, while the left foot without deodorant applied has a higher foot odor intensity of 3 and also produces isovaleric aldehyde. The amount was 4.0 times higher than the right foot. In subject No. 2, the same result was obtained, and the amount of isovaleric aldehyde generated was 2.8 times different.
From the above test results, it can be seen that the effect of the deodorant agent can be confirmed using the amount of isovaleric aldehyde as an index.

Example 4
Evaluation of Deodorant Agent Deodorant agent is sprayed on non-brominated socks. Thereafter, a test is conducted in the same manner as in Example 3 to examine whether or not the amount of isovaleric aldehyde is reduced by the deodorant agent. When the indicator for foot odor determination is decreased by the deodorant, the deodorant is evaluated as having a deodorizing effect and / or a deodorizing effect.

Example 5
Screening for foot odor suppressor In the experiment in which 1% by weight of L-leucine was added in Example 2, Staphylococcus. Epidermidis ATCC 12228 was used as a microorganism, and the test substance was added at various concentrations for the experiment. After the experiment is completed, the gas evaporated from the obtained culture solution is analyzed by the above analysis method, and the amount (C) of the produced isovaleric aldehyde is measured.
The same procedure as described above is performed without adding the test substance, and the amount (D) of isovaleric aldehyde present in the gas vaporized from the obtained culture solution is measured.
The amount of isovaleric aldehyde (C) is compared with the amount of isovaleric aldehyde (D) to determine whether the test substance reduces the amount of isovaleric aldehyde. When the isovaleric aldehyde is reduced by the test substance, the test substance inhibits the production of isovaleric aldehyde and is evaluated as having a deodorizing effect.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The foot odor can be objectively evaluated in a wide range up to a weak foot odor by the foot odor determination indicator and the foot odor determination method of the present invention. Further, the deodorant agent evaluation method of the present invention makes it possible to objectively and accurately evaluate the deodorant effect of the foot odor of the deodorant agent and the performance of the deodorant agent with a simple operation. In addition, the foot odor inhibitor screening method of the present invention enables efficient screening of foot odor inhibitors with a simple operation.

Claims (2)

A method for screening a foot odor inhibitor for suppressing the generation of foot odor,
(1) culturing a microorganism capable of producing isovaleric aldehyde in a medium containing a test substance and L-leucine,
(2) by measuring the amount of Lee Seo valeric aldehyde in the culture obtained in step (1), determining whether the test substance inhibits the production of iso-valeric aldehyde, and (3 ) A method for screening a foot odor inhibitor, comprising the step of selecting, as the foot odor inhibitor, a test substance that suppresses the production of isovaleric aldehyde in the step (2). The method for screening a foot odor inhibitor according to claim 1 , wherein the microorganism is at least one selected from the group consisting of Staphylococcus.aureus, Staphylococcus.epidermidis and Corynebacterium.minutissimum.