JP3313433B2 - Horse mackerel detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a sensor capable of acting as a substitute for the taste, which is one of the five senses of human beings, and uses the difference in taste of food and drink, which has been difficult to measure by an artificial sensor. The present invention relates to a technology for enabling detection and measurement. Food, such as drinking water for food and drink, the difference in taste of alcohol, etc., because it provides a technology to detect what should be called the difference in taste, in drinking water and alcohol production plant,
The present invention relates to a technology that enables the quality control to be performed by a mechanical device without manual operation.

[0002]

[Definition of terms] It is said that there are saltiness, sweetness, bitterness, sourness, and umami as basic components of taste, each of which has a degree of magnitude. These differences in taste that can be evaluated by human senses, or differences in saltiness (of the same type) for saltyness, can be grasped as physically measurable quantities, and differences in measurable taste or taste (Comparative or contrasting taste) is herein referred to as “adzuki”.

[0003]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 62-187252, for example, the concentration of each original taste (basic taste) component, that is, the concentration of a selected taste substance in an object to be measured is determined from the output values of a plurality of taste sensors. Calculated values were measured for horse mackerel by correcting each density value to a value representing the strength of each taste corresponding to human taste.

However, the taste sensor referred to in the above publication is a chemical sensor or a physical sensor that selectively detects a substance exhibiting each basic taste. Specifically, salt taste is a salt concentration meter,
The sourness was measured by a hydrogen ion index meter, and the sweetness was measured by a saccharimeter using the refractive index of the liquid to be measured. Since these sensors are selective, for example, a salt concentration meter that is trying to measure the strength of salty taste can measure the concentration of salt, but cannot measure the concentration of other substances that exhibit salty taste, and it suits human taste There was a limit to the correction. Speaking of color, it is like trying to get a color result using a sensor that only detects a single color.

[0005] In Japanese Patent Application Laid-Open No. 3-54446, a partially identical applicant discloses that a lipid substance comprising a molecule having a hydrophobic portion and a hydrophilic portion is fixed in a polymer matrix, and the surface thereof is fixed. A lipid molecular membrane having a structure such that the hydrophilic portion of the lipid molecule is aligned with the horse mackerel sensor,
It was shown that it could be a taste sensor that could replace human taste.

FIG. 8 shows the membrane diagram of the lipidic molecular membrane in a representation method used in a method of designing a chemical substance. The globular part shown by a circle in the lipid molecule is a hydrophilic group a, that is, a hydrophilic part a, and there is a hydrocarbon chain structure b (for example, an alkyl group) whose atomic arrangement extends long from it. In each case, two chains are extended to represent one molecule in each case, and the whole constitutes a molecule group. This part of the hydrocarbon chain is the hydrophobic site b. Such a lipid molecule group 31 is partially dissolved in a matrix 33 (a surface structure, a microstructure having a planar spread) on the surface of the membrane member 32 (for example, It is accommodated at 31 ') in FIG. The manner of its containment is
The hydrophilic sites are arranged on the surface.

FIGS. 5 (a) and 5 (b) show a multi-channel taste sensor using this lipid molecular membrane. In this figure, three sensitive parts of the multi-channel array electrode are shown. In the illustrated example, a 0.5 mmφ hole was penetrated through the base material, and a silver round bar was inserted into the hole to form an electrode. The lipid molecular membrane is adhered to the substrate via the buffer layer so as to contact the electrode.

FIG. 6 shows a horse mackerel measuring system using the multi-channel taste sensor. Prepare an aqueous solution of the taste substance, use it as the solution to be measured 11, and place it in a container 12 such as a beaker.
Put in. The taste sensor array 13 formed by arranging a lipid membrane and electrodes on an acrylic plate (substrate) as described above was placed in the solution to be measured. Before use, potassium chloride 1m
The electrode potential was stabilized with a mole / l aqueous solution. In the figure, 14-
1,..., 14-8 indicate the respective lipid membranes by black dots.

A reference electrode 15 is prepared as an electrode for generating an electric potential serving as a reference for measurement, and is placed in a solution to be measured. The taste sensor array 13 and the reference electrode 15 are installed at a predetermined distance. Since the surface of the reference electrode 15 is covered with a buffer layer 16 coated with 100 mMole / l of potassium chloride solidified with agar, the electrode system is eventually composed of silver 2 | silver chloride 4 | lipid membrane 3
(14) ｜ Measurement solution 12 ｜ Buffer layer (potassium chloride 100m mole
/ L) 16 | silver chloride 4 | silver 2

The electrical signal from the lipid membrane becomes an eight-channel signal in the figure, and is led to buffer amplifiers 19-1,..., 19-8 by leads 17-1,. Each output of the buffer amplifier 19 is selected by an analog switch (8 channels) 20 and applied to an A / D converter 21. The electric signal from the reference electrode 15 is also applied to the A / D converter 21 via the lead wire 18, and converts the difference from the potential from the membrane into a digital signal. This digital signal is appropriately processed by the microcomputer 22 and displayed by the XY recorder 23. In this example, an 8-channel taste sensor is used, and each channel has a different response characteristic to taste in order to obtain a lot of taste information that can reproduce human taste. It is composed of a molecular film.

[0011]

[Table 1]

In addition, the same applicant has also filed a patent application for “taste sensor and manufacturing method thereof” (Japanese Patent Application No. Hei.
020450). In the specification and drawings of this application, a molecular membrane closer to human taste organs than in the above-mentioned JP-A-3-54446 is shown. Then, the structure of a molecular film capable of utilizing a substance called an amphipathic substance (including lipid) having a hydrophilic group and a hydrophobic group or a bitter substance such as an alkaloid as a material of the molecular film was shown. In this structure, as shown in FIG. 7, the amphipathic molecule group 36 or the bitter substance molecule group 36 is arranged on the base film 7 provided on the substrate 1 such that the hydrophilic site indicated by a circle faces outward, It constitutes a monomolecular film.

The taste sensor referred to in the specification of the same applicant is a taste sensor and has physicochemical properties close to those of the tongue which is a human taste organ, and the same applies to different taste substances. A similar output can be obtained for a different taste, and some output can be obtained for a different taste. Speaking of color, this is a sensor that can detect color.

Further, the same applicant has applied for a method of detecting horse mackerel using the above-mentioned taste sensor (Japanese Patent Laid-Open No. 4-064053).
In order to perform the detection and measurement of horse mackerel with a taste sensor using lipid molecules with good reproducibility, a liquid exhibiting the same or similar horse mackerel as the sample liquid to be measured is used as a reference solution. Sufficiently immerse the sensor in the reference solution, apply a similar stimulus to the taste sensor for each measurement, and select the measurement time after the surface potential is stabilized and the intramembrane potential changes slowly, A method has been disclosed in which the reproducibility of the measured value by the taste sensor is improved, the variation in the measured value is reduced, and the discriminating power of horse mackerel is increased.

[0015]

However, the above method still has the following problems. That is, the absolute value of the surface potential continuously drifts. Once the sample solution is measured by the taste sensor, the sample solution permeates into the lipid membrane or adheres to the lipid membrane surface, so that the charge density on the lipid membrane surface changes and the taste sensor output drifts.

The reference liquid itself continuously changes by repeatedly measuring the reference liquid. If the taste sensor is intermittently immersed in the reference solution and the measurement is repeated in the same manner, even if there is a reference solution for washing, if the number of repetitions is large, the taste of the reference solution itself will continue due to contamination from the sample solution and air oxidation. Change.

When a reference liquid having the same or similar agility as the sample liquid is used, the concentration of the taste component in the sample liquid is substantially the same as the concentration of the taste component in the reference liquid. Once a taste component having a taste is once adsorbed by the reference solution, it is difficult to desorb the taste component from the lipid membrane.

[0018]

In order to address the problems described in the preceding section, the present invention focuses on the following two points. A first reference liquid and a second reference liquid are used. This is a measure taken to minimize the influence of the continuous drift of the taste sensor and the continuous change of the reference liquid itself by repeatedly measuring the reference liquid. In the previous detection method, a relative value (Vs-V0) from the reference value of the sample was calculated from the measured value V0 when the reference solution was measured and the measured value Vs when the sample solution was measured.
Since the continuous drift of the taste sensor was measured together, the variation was large. That is, assuming that the drift per unit time of the taste sensor is εmV / s, the measured value Vs when the sample liquid is measured can be expressed by the following equation. Vs = Vs '+ t.epsilon. Where Vs': a true sample measured value not including the drift of the taste sensor t: time The relative value (Vs-V0) is Vs-V0 = Vs'-V0 + t.epsilon. The measurement method of the present invention measures the measured value V0 when the first reference solution is measured and the measured value V0 when the second reference solution is measured.
k, the measured value V 0 'when the first reference liquid is measured again,
The relative value from the reference value of the sample ｛(Vs−V0 ′) − (Vk−V) is obtained from the measured value Vs when the sample liquid is measured.
0)｝ can be expressed as the following equation. {(Vs−V0 ′) − (Vk−V0)} = [{Vs ′ + (T + 2t) ε−V0 ′ ″ − (T + t) ε} −ΔVk ′ + tε−V0 ′ ″ } = Vs′−Vk Here, Vs': a true sample measurement value that does not include the drift of the taste sensor Vk ': a true second reference liquid measurement value that does not include the drift of the taste sensor V0'' : True first reference liquid measured value not including the drift of the taste sensor t: time from measurement of the first reference liquid to the second reference liquid and from the first reference liquid to measurement of the sample liquid T: second Based on the time required to measure the first reference liquid from the reference liquid, the relative value (Vs'-Vk ') which was not affected by the continuous drift of the taste sensor was successfully obtained. Further, the problem that the reference liquid itself continuously changes due to repeated measurement of the previous reference liquid is also caused by using the first reference liquid as shown in the equation (1). The change in taste no longer affected.

As the first reference liquid, a second reference liquid diluted with water is used. When the first reference liquid having the same or similar adjectiveness as the sample liquid is used, the concentration of the taste component in the sample liquid is substantially the same as the concentration of the taste component in the first reference liquid.
There is no problem because ionic taste components do not adsorb to the lipid membrane, but once the adsorbable taste components are adsorbed by the reference solution or sample solution, they are difficult to desorb from the lipid membrane. A second reference solution diluted with water was used. As a result, the taste components adsorbed by the second reference liquid and the measurement liquid were easily desorbed, the sensitivity was improved, and the taste discrimination ability was enhanced.

[0020]

According to the flowchart of FIG. 1, the first reference liquid → the second reference liquid → the first reference liquid → the sample liquid are measured in this order, and the relative value of the measured value of the sample liquid from the reference value ｛(Vs− V0 ')
By calculating-(Vk -V0) ば ら つ き, the variation of the relative value in the continuous drift of the taste sensor is eliminated, and even if the taste of the first reference liquid changes by using the first reference liquid, the measured value is obtained. When the concentration of the first reference solution was reduced by adding water, etc., the substance adsorbed on the membrane was easily desorbed by the first reference solution, and the amount of information of the taste sensor output increased. As good reproducibility,
It became possible to detect horse mackerel with higher discrimination ability.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a taste sensor using a lipid membrane as described in the section of the prior art, detection of horse mackerel (discrimination of difference) is carried out for seven commercially available coffee drinks. As lipid molecules used in taste sensors,
Eight types listed in Table 1 (numbers 1, 2, 3, 4, 7, 8, 1
0 to 11 lipids were sequentially numbered 1 to 8, and potential signals obtained therefrom are referred to as channels 1 to 8). Seven products of coffee beverages were blended and used for the first reference liquid and the second reference liquid. The procedure of horse mackerel detection is as follows.

1) A taste sensor using a lipid membrane is immersed in a storage solution (same as the first reference solution) for approximately 10 hours. 2) Take the taste sensor in and out of the first reference solution (for cleaning) 10 times. It may be said that it is washed with the first reference solution (for washing), it may be said that it is immersed intermittently in the first reference solution, or it can be said that it stimulates the surface of the lipid membrane of the taste sensor. . 3) Immerse the sample in the first reference solution prepared for measurement. After 20 seconds, measure the potential of the taste sensor.
And 4) Steps 2) and 3) are repeated at least twice, and for each measurement, it is determined whether the difference between the current measured value V0 and the previous measured value V0 is equal to or less than a predetermined value. If), proceed to step 5). 5) Take out the taste sensor from the first reference liquid (for measurement),
Wash with a second reference solution (for washing). (Same as 2)
Put in and out 10 times. 6) Immerse the taste sensor in the second reference solution (for measurement),
After a second, the potential Vk of the taste sensor is measured. 7) Put the taste sensor in and out of the first reference solution (for washing) again 10 times. It may be said that it is washed with the first reference solution (for washing), it may be said that it is immersed intermittently in the first reference solution, or it can be said that it stimulates the surface of the lipid membrane of the taste sensor. . 8) Immerse the sample in the first reference solution prepared for measurement. After 20 seconds, measure the potential of the taste sensor.
´. 9) Steps 7) and 8) are repeated at least twice, and it is determined whether or not the difference between the current measured value V0 'and the previous measured value V0' is equal to or less than a predetermined value for each measurement. If is stable), proceed to step 10). 10) Take out the taste sensor from the first reference liquid (for measurement),
Wash with sample solution (for washing). (10) as in (2) above
Get in and out. 11) Immerse the taste sensor in the sample solution (for measurement), and measure the potential Vs of the taste sensor after 20 seconds. 12) Return to measurement step 2) and repeat steps 2) to 11). When the process is repeated a predetermined number of times, the procedure ends.

This procedure is shown in FIG. When there are a plurality of sample liquids to be measured, the measurement order of the samples may be determined so that the rotation has randomness, and the average value may be obtained by repeatedly measuring.

Next, as a second embodiment, detection of horse mackerel is performed by assuming that the first reference liquid in the first embodiment is diluted twice by adding pure water to the second reference liquid. And The sample, the second reference solution and the procedure are the same as in the first embodiment. FIGS. 3 and 4 show graphs obtained by performing principal component analysis on the experimental results of the first embodiment and the second embodiment, respectively.
Each of the seven coffee beverages is plotted. As can be seen from the figure, the second principal component has information of 78.9% and 17.4%, respectively, as compared with the contribution ratio of the first principal component of 85.3% and the contribution ratio of the second principal component of 9.0% in the first embodiment. The amount increased about two-fold, and the ability to discriminate horse mackerel in coffee beverages increased.
This is because the product obtained by blending seven coffee beverages with the first reference liquid and diluted twice with pure water was used, so that the taste components adsorbed when the second reference liquid and the sample liquid were measured were easily removed. It is thought that the sensitivity was improved and the ability to discriminate the taste was enhanced. The method of the second embodiment is particularly effective for a sample containing a lot of adsorptive taste components such as coffee and beer.

[0025]

According to the method for detecting horse mackerel of the first invention,
In order to perform the detection and measurement of horse mackerel with a taste sensor using lipid molecules with good reproducibility, the first reference solution and the second reference solution should be close to the sample solution, and the first reference solution → The taste sensor is measured by measuring in the order of the second reference liquid → the first reference liquid → the sample liquid and calculating the relative value {(Vs−V0 ′) − (Vk−V0)} of the measured value of the sample liquid from the reference value. The variation of the relative value in the continuous drift was eliminated, and the use of the first reference liquid did not affect the measured value even if the taste of the first reference liquid changed.

In the method for detecting horse mackerel according to the second invention, the concentration of the first reference solution is further reduced by adding water or the like, whereby the substance adsorbed on the membrane is easily desorbed by the first reference solution, The information amount of the taste sensor output was increased, and the dispersion of the measured values was reduced. The method for detecting horse mackerel according to the second invention is particularly effective when a substance contained in a substance adsorbed on a lipid membrane, such as a bitter substance, is a measurement target.

[Brief description of the drawings]

FIG. 1 is a flowchart of a measurement procedure according to the present invention.

FIG. 2 is a diagram showing a measurement procedure according to the present invention.

FIG. 3 is a diagram in which, for seven products marketed as coffee drinks in the first embodiment, horse mackerel detection (difference discrimination) is performed, and a result of a principal component analysis of an experimental result is plotted.

FIG. 4 is a diagram of a principal component analysis in the second embodiment.

5A and 5B are schematic views of the taste sensor, FIG. 5A is a front view, and FIG. 5B is a cross-sectional view.

FIG. 6 is a view showing a measurement system of horse mackerel.

FIG. 7 is a schematic diagram showing a monomolecular film in an expression method used in a method of designing a chemical substance.

FIG. 8 is a schematic diagram showing a lipid membrane in an expression method used in a method of designing a chemical substance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Electrode 3 Lipid film 4 Buffer layer 5 Lead wire 10 Basic structure of measurement system of membrane potential 11 Solution to be measured 12 Container 13 Taste sensor array 14-1 to 14-8 Each lipid film (indicated by a black dot) 15 Reference electrode 16 Buffer layer 17-1 to 17-8 Lead wire 18 Lead wire 19-1 to 19-8 Buffer amplifier 20 Analog switch 21 A / D converter 22 Microcomputer 23 XY recorder 24 Ground potential 31, 31 ' Lipid molecule group 32 Membrane member 33 Matrix

Claims (2)

(57) [Claims] 1. A method for detecting a horse mackerel in a plurality of similar samples using a taste sensor using a membrane containing an amphipathic substance or a bitter substance, comprising the steps of: Preparing a second reference liquid exhibiting the same or similar horse mackerel as the sample, measuring the first reference liquid using the taste sensor (1), and using the taste sensor to detect the second reference liquid. Measuring the reference solution of (2),
Measuring the first reference liquid again using the taste sensor (3), measuring the sample liquid using the taste sensor (4), and the first step (1). The measured value V0 of the reference liquid, the measured value Vk of the second reference liquid in the step (2), and the measured value V0 of the first reference liquid in the step (3)
And the measured value Vs of the sample in step (4), the relative value of the sample from the reference value ｛(Vs−V0 ′) −
(Vk-V0)｝. (5). A method for detecting horse mackerel by performing the above-mentioned steps (1) to (5) for each sample. 2. A method for detecting a horse mackerel of a plurality of similar samples using a taste sensor using a membrane containing an amphipathic substance or a bitter substance, wherein the agitator exhibits the same or similar horse mackerel as the plurality of samples. A step of making a second reference liquid, a step of making a first reference liquid obtained by diluting the second reference liquid with water, and a step of measuring the first reference liquid using the taste sensor (1) Measuring the second reference liquid using the taste sensor (2), measuring the first reference liquid again using the taste sensor (3), using the taste sensor Measuring the sample liquid by (4),
The measured value V0 of the first reference liquid in the step (1) and the measured value Vk of the second reference liquid in the step (2) and the step (3)
The relative value {(Vs−V0 ′) − (Vk−V0)} from the reference value of the sample is obtained from the measured value V0 ′ of the first reference liquid and the measured value Vs of the sample in the step (4). Calculating step (5), wherein the steps (1) to (5) are performed.
The method of detecting horse mackerel by performing the procedure up to each sample.