JP2004093145A - Smell testing method and smell testing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make accurately, easily, and efficiently performable the test of odors. <P>SOLUTION: A vaporizing means 21 forcibly vaporizes a odorous substance Xa contained in liquid X to be inspected in a container 20a by heating, pressure reduction, bubbling, or the like. A smell water generating means 22 generates odor water X' where the smell substance Xa is dissolved into liquid whose constituents are known for storing in a container 20c by cooling, pressurization, bubbling, or the like. An analyzing means 23 analyzes the odor water X' in the container 20c by a sensor for liquid, such as a lipid film sensor. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for enabling odor inspection to be performed easily and with high reproducibility.
[0002]
[Prior art]
For example, factories and the like that manufacture beverages, noodle soups, soy sauce, and the like, not only inspect the taste of products but also inspect odors.
[0003]
The odor of such a product is the odor substance contained in the product that has spontaneously vaporized and scattered into the air, and humans perceive this by the olfactory nerve tissue in the nostrils.
[0004]
The odor of this type of product is one important factor that characterizes the product together with the taste, and is subject to product quality control.
[0005]
Conventionally, as the odor test for the above-mentioned products, a sensory test in which a person actually smells and tests the odor, a test using a sensor that responds to odor substances in gas, and the like have been performed.
[0006]
[Problems to be solved by the invention]
However, in a sensory test performed by a person, the test results vary depending on the examiner, and even if the same examiner, the test results vary due to a difference in physical condition.
[0007]
On the other hand, in the case of an inspection using a sensor that responds to gas, there are the following problems.
Cleaning after the odor substance is adsorbed on the sensor surface is extremely difficult, reproducibility is low, measurement intervals must be provided, and efficiency is poor.
[0008]
In addition, sensors that are sensitive to odor substances in the gas phase are limited, and the amount of information obtained is small, so that a slight difference in odor cannot be recognized.
[0009]
In addition, since the measurement is performed in the gas phase, it is difficult to control the gas so as not to be affected by other substances, and there is a large error in preparing a gas sample.
[0010]
An object of the present invention is to solve these problems and to provide an odor inspection method and an odor inspection device capable of accurately, simply and efficiently inspecting an odor.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the odor inspection method according to claim 1 of the present invention comprises:
Dissolving the odor substance in the gas phase in a known liquid to generate odor water;
Performing an analysis on the generated odor water.
[0012]
Further, the odor inspection method according to claim 2 of the present invention,
Forcibly vaporizing odorants in the liquid,
Dissolving the vaporized odor substance in a known liquid to generate odor water;
Performing an analysis on the generated odor water.
[0013]
Further, the odor inspection device according to claim 3 of the present invention,
Odor water generating means for dissolving odor substances in the gas phase in a known liquid to generate odor water,
Odor analysis means for analyzing odor water generated by the odor water generation means.
[0014]
Further, the odor inspection device according to claim 4 of the present invention,
Vaporization means for forcibly vaporizing odor substances in the liquid,
Odor water generation means for dissolving the vaporized odor substance in a known liquid to generate odor water,
Odor analysis means for analyzing odor water generated by the odor water generation means.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but before that, a process in which a person smells will be briefly described.
[0016]
In the case of humans, the surface of odor cells in the nasal cavity (hereinafter referred to as odor cells) is covered with water, and the odor substance inhaled from the nose dissolves into the water layer and reaches the odor cells I feel the smell.
[0017]
Therefore, a substance that does not dissolve in water cannot feel the smell. The present invention focuses on this point, and in response to a process in which a person senses an odor, an odor substance in a gas phase is dissolved in a known liquid to generate odor water, and analysis of the odor water is performed by a human. This is performed by a liquid sensor corresponding to odor cells.
[0018]
There are many types of liquid sensors as described later, but since the surface of human odor cells is covered with a lipid membrane, a sensor using a lipid membrane as a sensor has a configuration closer to a living body. And the possibility of identifying the different odors that a person feels.
[0019]
FIG. 1 shows the overall configuration of an odor inspection device 20 according to an embodiment of the present invention based on the above principle.
[0020]
The odor inspection device 20 forcibly vaporizes an odor substance contained in a test target liquid, dissolves the vaporized odor substance in a known liquid, generates odor water, and analyzes the generated odor water. It has a vaporizing means 21, a odor water generating means 22 and an analyzing means 23.
[0021]
The vaporizing means 21 is for forcibly vaporizing the odorous substance Xa contained in the liquid X to be tested, such as beverages and noodle soup in the container 20a.
[0022]
As shown in FIG. 2A, for example, the vaporizing means 21 heats the test liquid X by a heater 21a such as an electric heater or a burner (in this case, moisture in the test liquid X is also vaporized). 2), or aeration (also referred to as bubbling) of the test liquid X with an odorless gas (nitrogen, air, or the like) by the pump 21b as shown in FIG. Either of the substances contained in the test liquid X, the easily-vaporizable odor substance Xa, is forcibly applied by any one of the methods of decompressing the inside of the container 20a containing the target liquid X or any combination of these methods. Vaporize.
[0023]
In addition, the taste substance Xb (salty substance, sweet substance, sour substance, umami substance, bitter substance) contained in the test liquid X such as beverages and noodle soup is generally not vaporized by the above method because of its large molecular weight.
[0024]
Further, here, the odor substance Xa is forcibly vaporized from the test liquid X by the vaporization means 21. However, when the test target is a highly volatile odor substance, the vaporization means 21 is omitted. You can also. In this case, the vaporized odor substance may be simply collected and sent to the odor water generating means 22.
[0025]
The odor substance Xa vaporized by the vaporizing means 21 is sent to the odor water generating means 22 via the connecting pipe 20b so as not to mix other surrounding gases.
[0026]
The odor water generating means 22 is for generating the odor water X ′ in which the vaporized odor substance Xa is dissolved in a known liquid, and performs a cooling process on the vaporized odor substance Xa, and the odor water X ′ by the vaporized odor substance Xa. By performing at least one of aeration (bubbling) and pressure treatment, odor water X 'is generated and stored in the container 20c.
[0027]
For example, when a heat treatment is included as the vaporizing means 21, as shown in FIG. 3A, the vaporized odor substance Xa and water W (water vapor) are cooled by the cooler 22a. As a result, odor water X ′ in which the odor substance Xa is dissolved in the water is generated and stored in the container 20c.
[0028]
As shown in FIG. 3 (b), the tip of the pipe 22b connected to the connecting pipe 20b is made equivalent to tasteless or odorless water previously stored in the container 20c, or a reference liquid used for analysis described later. , And aerated with the vaporized odor substance Xa to generate odor water X ′ in which the odor substance Xa was dissolved.
[0029]
Although not shown, the odor substance Xa vaporized by the vaporizing means 21 may be pressurized by a pressurizer and dissolved in tasteless and odorless water to generate odor water X '.
[0030]
The odor water X 'generated by the odor water generation means 22 contains only a known component of the liquid and the odor substance Xa contained in the test liquid X, and the taste substance Xb of the test liquid X Is not included.
[0031]
This odor water X 'is analyzed by the odor analysis means 23.
The odor analysis means 23 has a sensor sensitive to a substance in the liquid, and analyzes the odor based on the output of the sensor when the sensor is immersed in the odor water X '.
[0032]
As a sensor used in this odor analysis, a sensor described below is used. In general, a sensor is composed of three parts: a receiving part, a converting part, and a recognizing part.
[0033]
The receiving portion includes a cast film formed by mixing a polymer and a lipid, an LB film, a film obtained by chemically modifying a lipid on an electrode surface with an SH group, a polymer film having a functional group, a metal film or a metal semiconductor film, Further, a bio-related substance (generally referred to as a biosensor, which includes an enzyme sensor, a microorganism sensor, an immunosensor, an organelle sensor, and the like) is exemplified.
[0034]
In addition, as the conversion unit, the electrical characteristics (potential and impedance) of the film, the amount of adsorption (which can be measured in an aqueous solution due to a change in the frequency of the crystal unit, and light) (Raman spectroscopy, spectrophotometry Total), heat, etc.
[0035]
In some cases, the impedance is measured according to the potential while applying a positive or negative potential to the film. In this case, it is known that a response similar to a lipid membrane can be obtained even with a metal electrode.
[0036]
In addition, it is possible to pass through cyclic voltammetry or cyclic amperometry in which information on the film is checked from the voltage-current characteristics when an AC voltage or an AC current is applied.
[0037]
Furthermore, when measuring the total amount of ionic odor substances, a conductivity meter is also effective, and a pH meter can also be used to analyze an odor substance exhibiting sourness.
[0038]
For an aqueous solution, many ion sensors for measuring various ions can also be used.
[0039]
In the following description, a case where a lipid membrane sensor is used will be described.
The lipid membrane sensor is configured such that a lipid and a polymer material are mixed at a predetermined ratio to form a membrane, and an electrode is provided on the membrane to output a potential on the membrane surface. It has properties that change under the influence of substances in the liquid, and the substance and sensitivity to react differ depending on the lipid material and content.
[0040]
This kind of lipid membrane sensor also responds to the taste substance contained in the test liquid X, but as described above, the odor water X ′ obtained by performing the vaporization processing and the liquefaction processing on the test liquid X. Does not contain the taste substance Xb, the response of the lipid membrane sensor is dominated by the influence of the odor substance Xa.
[0041]
Therefore, if the odor water X 'is analyzed using this lipid membrane sensor, the characteristics of the odor of the test liquid X can be accurately grasped.
[0042]
Here, the result of actually analyzing the smell of noodle soup using a lipid membrane sensor will be described.
[0043]
As shown in FIG. 4, the system of the analysis means 23 used for this analysis includes a lipid membrane sensor 24, a reference electrode 25, and a potential difference detection circuit 26 which outputs the membrane potential of the lipid membrane sensor 24 with respect to the potential of the reference electrode 25. An A / D converter 27 for converting a voltage output from the potential difference detection circuit 26 to a digital value, and a computer 28 for performing storage processing, arithmetic processing, and the like on the voltage converted to a digital value by the A / D converter 27. Have been.
[0044]
Further, in addition to the odor water X ', the reference liquid R and the cleaning liquid C are prepared by putting them in the containers 20d and 20e.
[0045]
The reference solution R is an aqueous solution of 1 mM (mmol) potassium chloride (KCl) +0.03 mM tartaric acid, which is almost tasteless and odorless near human saliva, and the washing solution C is an aqueous solution of 30% ethanol + 100 mM hydrochloric acid (HCl). .
[0046]
The lipid membrane sensor 24 may be one type or a plurality of types. Here, one type of lipid membrane sensor 24 using Dioctyl phenyl-phosphonate (DOPP) as a lipid will be described.
[0047]
The lipid membrane 24a used in the lipid membrane sensor 24 is formed by mixing about 1 ml of the above-mentioned lipid DOPP and about 800 mg of a polymer material PVC (polyvinyl chloride). The lipid film 24a is fixed to the surface of the base 24b formed in a shape, and the electrode plate 24d is fixed to the opposite surface of the lipid film 24a via the buffer layer 24c, and one end is electrically connected to the electrode plate 24d. One end of a lead wire 24f is connected to the other end of the rod-shaped electrode 24e. The buffer layer 24c uses potassium chloride hardened with agar.
[0048]
The reference electrode 25 is for outputting a potential serving as a reference for measurement, is formed in a rod shape, and its lower periphery is covered with the same buffer layer 25a as the buffer layer 24c of the lipid membrane sensor 24. One end of a lead wire 25b is connected to the upper end.
[0049]
The lipid membrane sensor 24 and the reference electrode 25 can be automatically or manually immersed in the odorous water X ', the reference liquid R, and the cleaning liquid C while maintaining a predetermined interval with a support member (not shown).
[0050]
The potential difference detection circuit 26 is connected to the other ends of the lead wires 24f and 25b, detects the membrane potential of the lipid membrane sensor 24 based on the potential of the reference electrode 25, and outputs the membrane potential to the A / D converter 27.
[0051]
The measurement for the odor water X ′ using the lipid membrane sensor 24 was performed according to the procedure shown in FIG.
[0052]
That is, first, the lipid membrane sensor 24 and the reference electrode 25 are immersed in the reference liquid R, and the voltage Vr output from the A / D converter 27 at that time is stored as a measured value (S1, S2).
[0053]
Next, the lipid membrane sensor 24 and the reference electrode 25 are immersed in the odor water X ', the voltage Vs output from the A / D converter 27 at that time is stored as a measured value, and Vs-Vr is calculated. The calculation result is stored as a first feature value (hereinafter, referred to as a relative value) Va (S3 to S6).
[0054]
Then, the lipid membrane sensor 24 and the reference electrode 25 are immersed again in the reference liquid R (may be housed in a container different from the previous reference liquid R) (the lipid membrane sensor 24 and the reference electrode 25 May be lightly washed), then store the voltage Vr 'output from the A / D converter 27 as a measured value, further calculate Vr'-Vr, and use the result of the calculation as the second characteristic. The value is stored as the value Vb, and the lipid membrane sensor 24 and the reference electrode 25 are immersed in the cleaning liquid C for cleaning (S7 to S11).
[0055]
The second characteristic value Vb depends on an odorant having an adsorptivity to the lipid membrane 24a among odorants contained in the odor water X '. Hereinafter, this characteristic value will be referred to as a CPA value. That.
[0056]
Further, as shown by a dotted line in FIG. 5, a series of processes from S1 to S11 is repeated a plurality of times, a plurality of feature values are obtained, and an averaging process is performed to improve the accuracy of each feature value. Can be higher.
[0057]
The above measurement was performed on the odor water generated from each of the six types of noodle soups X1 to X6 having different brands, and when the correlation between the measurement results and the sensory test results was obtained, the results of FIGS. 6 and 7 were obtained. Was.
[0058]
FIG. 6A shows the relationship between the results of the sensory test on the strength of the bonito soup aroma of each of the noodle soups X1 to X6 and the relative value Va for each odor water, and the results of the sensory test and the relative values. It was confirmed that there was a strong correlation with Va.
[0059]
FIG. 6B shows the relationship between the result of the sensory test on the intensity of the odor of each of the noodle soups X1 to X6 and the relative value Va for each odor water. It can be seen that there is no correlation with the value Va.
[0060]
FIG. 7A shows the relationship between the sensory test results for the intensity of the odor of each noodle soup X1 to X6 and the CPA value Vb for each odor water. It was confirmed that there was a strong correlation with the value Vb.
[0061]
FIG. 7B shows the relationship between the sensory test results on the strength of the bonito soup aroma of each noodle soup X1 to X6 and the CPA value Vb for each odor water. It can be seen that there is no correlation with the CPA value Vb.
[0062]
That is, among the measurement results obtained by the lipid membrane sensor 24, the relative value Va changes almost monotonically in accordance with the intensity of the noodle soup bonito dashi, and the CPA value Vb changes approximately monotonically in accordance with the intensity of the odor of the kun. It can be seen that it has changed.
[0063]
Therefore, for example, when the relative value Va and the CPA value Vb are obtained for the noodle soup whose odor is unknown and the odor water is generated in the same manner as described above and the measurement is performed using the lipid membrane sensor 24, the noodle soup is obtained. The degree of bonito soup aroma and the intensity of the odor can be accurately grasped without sensory tests.
[0064]
Further, here, an example in which the odor is analyzed using the lipid membrane sensor 24 composed of the lipid DOPP has been described. However, although the experimental results are omitted, two different types of lipids as shown in the following (a) to (d) are used. Even when a lipid membrane sensor containing the same is used, a high correlation between the relative value Va and the strength of the bonito dashi aroma has been confirmed.
[0065]
(A) n-Tetradecyl Alcohol
+ Phosholic Acid Di-n-decyl Ester
(B) Dioctyl phenyl-phosphonate
+ Phosholic Acid Di-n-decyl Ester
(C) 2-Nitrophenyl octyl ether
+ Phosholic Acid Di-n-decyl Ester
(D) DOPP + Hexadecanoic Acid
[0066]
In addition to the above lipid membrane, it is also possible to use a lipid membrane sensor composed of two or three different lipids as in the following (e) to (h). 24 and a plurality of lipid membrane sensors arbitrarily selected from a plurality of types including the lipid membrane sensors (a) to (h) to perform multi-dimensional measurement on the odor water to characterize the odor water. If detected, more detailed analysis is possible.
[0067]
(E) n-Tetradecyl Alcohol
+ Tetradodecyl ammonium bromide
(F) DOPP
+ Tetradodecyl ammonium bromide
(G) 2-Nitrophenyl octyl ether
+ Tetradodecyl ammonium bromide
(H) DOPP
+ Phosholic Acid Di-n-decyl Ester
+ Tetradodecyl ammonium bromide
[0068]
Further, in the above description, an example in which odor analysis is performed using a lipid membrane sensor has been described. However, it is also possible to extract and analyze characteristics of odor substances using the other sensors described above. Even when it is used, it is possible to accurately analyze only the odor substance contained in the test liquid X without being affected by the taste substance originally contained in the test liquid X.
[0069]
In addition, since the analysis target is a liquid, it is extremely easy to manage so that other components are not mixed, and accurate analysis can be performed.
[0070]
In addition, since an aqueous solution sensor is used, organic solvents and water can be used for cleaning, and adsorbed odor substances can be effectively removed without damaging the sensor, and highly reproducible measurement can be performed efficiently. Can be done
[0071]
In addition, sensors for aqueous solutions are extremely rich in types as described above, and a large amount of information can be obtained by using a large number of sensors, and a slight difference in odor can be detected from these information amounts. Becomes possible.
[0072]
The above experimental results were obtained by examining the presence or absence of a correlation between the intensity of a specific odor and the characteristic value. The characteristics of the characteristic values of the sample or the sample deliberately deteriorated are examined and stored by using at least one of the above-described plural types of lipid membrane sensors, and the measurement results of the test liquid X and the characteristics stored in advance are stored. By comparing the characteristic of the value with the value, it is possible to determine whether or not the odor of the liquid X to be tested is good or not, and to determine the deterioration.
[0073]
In the above description, the noodle soup was used as the liquid to be tested, but the present invention can be similarly applied to beverages, seasonings such as soy sauce, perfumes, and the like.
[0074]
【The invention's effect】
As described above, the odor detection method and odor inspection device of the present invention dissolve odor substances contained in a gas phase or odor substances contained in a liquid and forcibly vaporized into a known liquid to remove odor water. It is generated and analyzed for the generated odor water.
[0075]
As described above, since the analysis target is a liquid, it is extremely easy to manage so that other components are not mixed, and accurate analysis can be performed.
[0076]
In addition, since an aqueous solution sensor is used, organic solvents and water can be used for cleaning, and adsorbed odor substances can be effectively removed without damaging the sensor, and highly reproducible measurement can be performed efficiently. Can be done
[0077]
In addition, sensors for aqueous solutions are extremely rich in types, and by using a large number of sensors, a large amount of information can be obtained, and a slight odor difference can be detected from these information amounts. .
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of a main part of the embodiment. FIG. 3 is a diagram illustrating a configuration example of a main part of the embodiment. FIG. 5 is a diagram showing a configuration example of a main part of the embodiment. FIG. 5 is a diagram showing a measurement procedure by the main part shown in FIG. 4. FIG. 6 is a diagram showing an example of a measurement result. Explanation of reference numerals]
20 odor inspection device, 21 vaporization means, 22 odor water generation means, 23 analysis means, 24 lipid membrane sensor, 25 reference electrode, 26 potential difference detection circuit, 27 A / D converter, 28 Computer

Claims (4)

Dissolving the odor substance in the gas phase in a known liquid to generate odor water;
Analyzing the generated odor water. Forcibly vaporizing odorants in the liquid,
Dissolving the vaporized odor substance in a known liquid to generate odor water;
Analyzing the generated odor water. Odor water generation means for dissolving odor substances in the gas phase in a known liquid to generate odor water,
An odor analyzer comprising: an odor analyzer that analyzes odor water generated by the odor water generator. Vaporization means for forcibly vaporizing odor substances in the liquid,
Odor water generation means for dissolving the vaporized odor substance in a known liquid to generate odor water,
An odor analyzer comprising: an odor analyzer that analyzes odor water generated by the odor water generator.

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