JPH075147A - Taste sensor and organic film therefor - Google Patents

Abstract

PURPOSE:To obtain taste information, especially of sweet taste, in which measurement error is suppressed by arranging a molecule group of bitter taste substance while covering the entire surface of an electrode on the side coming into contact with a liquid to be measured so that sum of charges at the hydrophilic part directing toward the contacting part will be zero. CONSTITUTION:Molecule groups 61, 62 of a bitter taste substance are arranged on a base film 9 formed on a substrate 1 while directing the hydrophilic part outward over the entire surface of an electrode 2 on the side coming into contact with a liquid to be measured thus forming a single molecule film. In this regard, the molecule group 61 to be charged positive in an aqueous solution is mixed with the molecule group 62 to be charged negative at such ratio as the total charge will be zero thus substantially nullifying the reaction of an electrolyte, for detecting the acid and salty tastes, on the anion and cation. Since a taste sensor having conditioned surface charge is employed, taste information is increased and the sensor can be employed effectively even in case of sweet taste. For example, the weight of sweet taste term is increased in the simultaneous equations of taste in order to suppress measurement error of sweet taste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial sensor capable of substituting the five senses of a human being, and in particular to a sensor or a transducer, which substitutes for the human sense, which has not been possible by the conventional artificial sensor. Regarding electronic devices called.

[0002]

[Meaning of terms] It is said that there are salt, sweetness, bitterness, sourness, and umami as basic elements of taste, and it is said that each has a different degree. These taste differences that can be evaluated by the human sense, or saltiness (similar kind) differences in saltiness, can be grasped as a physically measurable amount, and the measurable taste or taste difference. (Comparative or contrasting taste) is referred to herein as "horse mackerel".

[0003]

2. Description of the Related Art Conventionally, for example, as disclosed in Japanese Unexamined Patent Publication No. 62-187252, the original taste (basic taste) component in a measurement object, that is, the concentration of a selected taste substance is determined from the output values of a plurality of taste sensors. The horse mackerel was measured by calculating and correcting each concentration value to a value representing the strength of each original taste that matches the taste of a person. 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, saltiness is a salt concentration meter, acidity is a hydrogen ion index meter, and sweetness is sweetness. Was a sugar meter utilizing 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 saltiness can measure the concentration of salt, but it cannot measure the concentration of other substances that have a salty taste and is suitable for human taste. However, there was a limit to the correction, and it was impossible to show the correct amount of feeling. By analogy with color, it was like trying to obtain color results using a sensor that senses only a single color.

The same applicant previously filed a patent application for "Taste sensor and its manufacturing method" (Japanese Patent Application No.
No. 190819). In the specification and drawings of this application, a lipid substance composed of a molecule having a hydrophobic portion and a hydrophilic portion is fixed in a polymer matrix, and the hydrophilic portion of the lipid molecule is attached to the surface of the substance. It was shown that the lipidic molecular film with such a structure that they are aligned becomes a taste sensor, that is, a taste sensor that can replace the human taste.

FIG. 3 is a diagram showing the membrane formula of the lipidic molecular membrane by the expression method used in the method of designing chemical substances. The spherical portion indicated by a circle in the lipidic molecule is a hydrophilic group a, that is, a hydrophilic portion a, and has a hydrocarbon chain structure b (for example, an alkyl group) from which the atomic arrangement extends long. In each figure, two chains extend in each case to represent one molecule, and the whole constitutes a molecule group. The portion of this hydrocarbon chain is the hydrophobic site b. Such a lipid molecule group 6 is partly dissolved in the matrix 8 (surface structure, microscopic structure having a planar spread) on the surface of the membrane member 7 (for example, a form). It is accommodated at 6 ') in FIG. The way it is stored is
The hydrophilic parts are arranged on the surface.

FIGS. 5 (a) and 5 (b) show a multi-channel taste sensor using this lipidic molecular film. In this figure, three sensitive parts of the multi-channel array electrode are shown. In the example shown in the drawing, a 0.5 mmφ hole is penetrated through the base material 1, and a silver round bar is inserted therein to form the electrode 2. The lipidic molecular film 3 is attached to the substrate 1 so as to contact the electrode 2 via the buffer layer 4.

FIG. 6 shows a horse mackerel measuring system using the multi-channel taste sensor. Make an aqueous solution of the taste substance, use it as the solution to be measured 11, and put it in a container 12 such as a beaker.
Put in. The taste sensor array 13 prepared by arranging the lipid film and the electrode on the acrylic plate (base material) as described above was put in the solution to be measured. 1m potassium chloride before use
The electrode potential was stabilized with a mole / l aqueous solution. 14- in the figure
1, ... 14-8 are the lipid membranes shown by black dots. A reference electrode 15 is prepared as an electrode that generates an electric potential that serves as a reference for measurement, and the reference electrode 15 is placed in the solution to be measured. The taste sensor array 13 and the reference electrode 15 are installed at a predetermined distance. The surface of the reference electrode 15 is covered with 100 m mole / l of potassium chloride solidified with agar as the buffer layer 16, so that the electrode system is eventually silver 2 | silver chloride | lipid membrane 3 (14) | Measurement solution 12 ｜ Buffer layer (potassium chloride 100m mole / l) 16
| Silver chloride | Silver 2

The electric signal from the lipid membrane becomes a signal of 8 channels in the figure and is led to the buffer amplifiers 19-1, ..., 19-8 by the lead wires 17-1 ,. Each output of the buffer amplifier 19 is selected by the analog switch (8 channels) 20 and added to the 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 the difference from the potential from the membrane is converted 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 eight-channel taste sensor is used, and each channel has different response characteristics to horse mackerel in order to obtain a large amount of taste information capable of reproducing human taste, as shown in Table 3. It is composed of a lipidic molecular film mixed with lipids.

[0009]

[Table 3]

[0010] Further, the same applicant has filed on "Taste sensor and its manufacturing method" (Japanese Patent Application No. 3-020450) and "Sensor".
We have also filed a patent application for Japanese Patent Application No. 3-122636. In the specification and drawings of these applications, the previous application (Japanese Patent Application No. 1-190819)
No.) showed a molecular film closer to the human taste organs. "Taste sensor and its manufacturing method" (Japanese Patent Application No. 3-0204)
No. 50) has shown the structure of a molecular film that can use, as a material for this molecular film, an amphipathic substance having a hydrophilic group and a hydrophobic group (including a lipid) or a bitter substance such as an alkaloid. In this structure, as shown in FIG. 4, the amphipathic molecule group 6 or the bitter substance molecule group 6 is aligned on the base film 9 provided on the substrate 1 with the hydrophilic portion indicated by a circle facing outward, It constitutes a monolayer. Then, in the "sensor" (Japanese Patent Application No. 3-122636), a structure in which a hydrophobic group or the like is directly chemically bonded to the substrate electrode is shown, and durability is improved.
A sensor with improved sensitivity to non-electrolytes such as sucrose was shown.

The taste sensor described in these specifications of the same applicant is a taste sensor, and has a physicochemical property close to that of the tongue, which is the taste organ of human being, and the same taste difference substance even if the taste substances are different. If so, the same output can be obtained, and some output can be obtained for different horse mackerels. For example, this is a sensor that can detect color.

As described in the preceding paragraph, for example, Japanese Patent Laid-Open No. 62-18
In Japanese Patent No. 7252, it is difficult to detect all the taste substances contained in the liquid to be measured in the measurement of horse mackerel using a plurality of chemical or physical sensors that selectively detect the taste substances. However, because the horse mackerel could not be detected completely, no measurement results that match the taste of humans were obtained no matter how corrected.

On the other hand, if a taste sensor capable of detecting horse mackerel is used regardless of the type of taste substance contained in the liquid to be measured, the leakage of horse mackerel detection is much less, but the output characteristics of the taste sensor are non-linear. However, the signal processing is complicated to some extent, the number of learning data becomes enormous, and sometimes the accuracy is low.

Therefore, the same applicant previously filed a patent application for the "horse mackerel measuring method" (Japanese Patent Application No. 3-87598).
issue). In the specification and drawings of this application, although the taste sensor is used, a signal processing is simple, a small amount of learning data is required, and an accurate horse mackerel measuring method is shown. It has been shown that the strength of the basic taste can be obtained as a value converted into the concentration of a representative taste substance representing a substance exhibiting each basic taste. The output of a taste sensor using a molecular film of an amphipathic substance or a bitter substance is non-linear,
Although it was said that the signal processing would be complicated due to that, the inventors have found by experiments that the output of the taste sensor can be regarded as linear for each basic taste within a limited range. Based on this fact, the above-mentioned problems were solved by the following method.

A plurality of taste sensors using a molecular film of an amphipathic substance or a bitter substance are used. First, the sensitivity of each taste sensor in the measurement range to each basic taste is obtained, and then the sensitivity obtained in We decided to calculate the strength of horse mackerel from the output of each taste sensor. The strength of horse mackerel was determined by determining a representative taste substance for each basic taste contained in the object to be measured and converting it into a concentration of the taste substance.

Within a limited range, the output of the taste sensor can be regarded as linear for each basic taste, and therefore, for the sensitivity measurement with addition of the reference liquid E0 and the substance Bi exhibiting a certain amount of the basic taste Ai to the reference liquid E0. When the liquid is measured by the taste sensor Sj, the sensitivity Wij of the taste sensor Sj to the basic taste (concentration of the substance exhibiting the added taste) Wij can be obtained from the outputs thereof.

Then, the reference liquid E0 is applied by the taste sensor Sj.
And the sample liquid Es to be measured is measured, and the outputs Vj0 and Vjs of the taste sensor Sj and the sensitivity Wij are substituted into the equation (1),
If the simultaneous equations are solved, the concentration of the substance exhibiting each basic taste (
) Is required. Vjs-Vj0 = ΣWij · log (xi / ri) (1) (The range of Σ is from i = 1 to m) where ri is the substance B having the basic taste Ai in the reference solution E0.
is the concentration of i.

For example, four kinds of basic taste Ai (i = 1,2,3,
4), eight taste sensors Sj (j = 1,2,3,4,5,6,7,8
), The following simultaneous equations are established for each sample liquid to be measured. Here, log (x i of equation (1)
/ Ri) is set as Xi. V1s-V10 = W11X1 + W21X2 + W31X3 + W41X4 V2s-V20 = W12X1 + W22X2 + W32X3 + W42X4 V3s-V30 = W13X1 + W23X2 + W33X3 + W43X4 V4s-V40 = W14X1 + W24X2 + W34X3 + W44X4 V5s-V50 = W15X1 + W25X2 + W35X3 + W45X4 V6s-V60 = W16X1 + W26X2 + W36X3 + W46X4 V7s- V70 = W17X1 + W27X2 + W37X3 + W47X4 V8s-V80 = W18X1 + W28X2 + W38X3 + W48X4 This simultaneous equation is solved by the least squares method to find the concentration xi of the substance having each basic taste.

[0019]

Although the taste sensor and the measuring method as described above have been used, the horse mackerel can be measured relatively easily and accurately, but it is still as follows. There was a problem. That is, the sensitivity of the taste sensor to sweetness is lower than the sensitivity to saltiness, sourness, and bitterness, and since the weight occupied by the term of sweetness in the simultaneous equations is small, the substance exhibiting the sweetness obtained by solving the simultaneous equations is expressed. That is, the error of the density becomes large. The object of the present invention is to solve the above problems,
The object is to realize a taste sensor and an organic film for a taste sensor that can obtain horse mackerel information (especially for sweetness) with less measurement error.

[0020]

[Means for Solving the Problems] In order to solve the above-mentioned problems, sourness and salty taste are tastes exhibited by electrolytes, and a taste sensor reacts with cations or anions of those electrolytes to detect sourness and salty taste. By utilizing the fact that it is detected, the reaction of the electrolyte with respect to cations and anions was made substantially zero.

That is, a plurality of types of the taste sensor are fixed to the electrode, covering the entire surface of the electrode and the side of the electrode in contact with the solution to be measured, and having a hydrophilic portion facing the side in contact with the solution to be measured. Of the amphipathic substance or the bitter substance molecule group, and by selecting a combination and a mixing ratio of the plurality of types of amphipathic substances or bitter substances, and is directed to the side in contact with the measured solution. In addition, the sum of the total charges of the hydrophilic portion was set to be substantially zero.

Further, the taste sensor organic film contains a plurality of kinds of amphipathic substances or bittering substance molecules having a hydrophilic portion and a hydrophobic portion and the amphiphilic substance or bittering substance molecules group. And a membrane having a matrix capable of being on the surface, at least a part of the group of molecules of the amphipathic substance or bitter substance is contained in the matrix of the membrane so that its hydrophilic sites are arranged on the surface, and The combination of the plurality of kinds of amphipathic substances or bitter substances and the mixing ratio were selected so that the sum of all charges of the hydrophilic sites arranged on the surface becomes substantially zero.

[0023]

[Function] The sourness and the salty taste are tastes exhibited by the electrolyte, and the taste sensor detects the sourness and the salty taste by reacting with the cations and anions of the electrolytes. Therefore, if the sum of all charges on the surface of the taste sensor film is zero, it apparently does not react with ions. That is, the output becomes zero.

[0024]

EXAMPLES A taste sensor and an organic film for a taste sensor according to the present invention are shown in FIGS. The difference from the conventional taste sensor and the film for taste sensor shown in FIG. 3 and FIG. 4 described above is that the molecule group 61 of the bitter substance or amphipathic substance that is positively charged in the aqueous solution (in FIG. 1 and FIG. 2). The hydrophilic portion a is indicated by a white circle) and the negatively charged molecule group 62 of a bitter substance or amphipathic substance (the hydrophilic portion a is indicated by a black circle in FIGS. 1 and 2) is a taste sensor or an organic substance for a taste sensor. That is, the charge is contained in the film as a whole so that the charge becomes substantially zero. Examples of bitter substances and amphipathic substances used in the present invention are summarized in Table 1 together with the polarity of charging in an aqueous solution.

[0025]

[Table 1]

As shown in the schematic diagrams of FIGS. 1 to 4, the characteristics of the molecular structure of these amphipathic substances are as follows: a hydrophobic site in which the atomic arrangement extends in the longitudinal direction and a long-running atomic group. It can be pointed out that there is a hydrophilic site at or near one end. Moreover, as the hydrophilic portion, there are a phosphoric acid group, an amino group, an ammonium group, a carboxyl group, a hydroxyl group and the like.

From the bitter substances and amphipathic substances,
Dioctyl phosphate (2 which is negatively charged in aqueous solution)
Experiments were carried out with C ₈ POOH) and trioctylmethylammonium chloride (TOMA), which is positively charged in aqueous solution. The mixing ratio of 2C ₈ POOH and TOMA is 100: 0, 90:10, 70:30, 50: 5.
0, 45:55, 40:60, 35:65, 3
It was set to 0:70.

The matrix supporting the amphiphile is
Thermoplastic polyvinyl chloride (PVC) was used, which is easily available and easy to handle. PVC dissolves in tetrahydrofuran (THF), nitrobenzene, cyclohexanone, etc. and can be made soft or hard by changing the mixing ratio with a plasticizer, so it has the convenience of being able to use properly depending on the application. In addition, it is characterized by stable quality and ease of molding.

PVC, a plasticizer and an amphipathic substance are generally used as follows:
Mix in a 3: 1 weight ratio. If a plasticizer is not added, the finished organic film becomes cloudy or non-uniform, which is not preferable. Further, depending on how to select the amphipathic substance / plasticizer, the mixing ratio, and the mixing method, white turbidity or nonuniformity may occur in the finished organic film. Dioctyl phthalate (DOP), dioctyl phenyl phosphonate (DOPP) or tricresyl phosphate (TCP) is used as a plasticizer, and an amphipathic substance (2C ₈ POOH and TOMA) and PVC are mixed in the above mixing ratio. Dissolve about 400 mg in 10 cc of THF and keep it at about 30 ° C on a uniform heated plate for about 2 hours,
The organic film was formed by evaporating THF. The thickness of the organic film thus obtained was about 200 μm. In order to volatilize THF, the object can be achieved even if the pressure is reduced at room temperature, but it seems that better heating can be obtained by heating a little.

This organic film was immersed in an electrolyte solution such as a saline solution of about 10 mmole / l or an aqueous potassium chloride solution.
After soaking for about a minute, the hydrophilic group of the amphipathic substance is obtained in a stable state in which the molecular arrangement in which the hydrophilic groups are aligned on the surface is obtained, and it functions as a taste sensor. In addition to PVC mentioned above, there are substances listed in Table 2 as materials for forming a matrix for fixing a bitter substance and an amphipathic substance.

[0031]

[Table 2]

A multi-channel type taste sensor was prepared by using the organic film produced by the above method. The multi-channel type taste sensor is as shown in FIGS. 5 (a) and 5 (b), and the horse mackerel measuring system using this multi-channel type taste sensor is shown in FIG. Both are as described in the section of [Prior Art].

The multi-channel type taste sensor has 8 channels, and each of 1 to 8 channels has the above-mentioned 2C.
₈ Mixing ratio of POOH and TOMA 100: 0, 90:
10, 70:30, 50:50, 45:55,
40:60, 35:65, 30:70 organic films are used. As the solution to be measured, tartaric acid was selected as the substance exhibiting sourness, and sodium chloride was selected as the substance exhibiting salty taste, and their aqueous solutions were used.

The results obtained from this experiment are shown in FIG.
Shown in (b). FIG. 7 (a) is a response pattern to tartaric acid, and FIG. 7 (b) is a response pattern to sodium chloride. These show changes in the pattern depending on the density, and the upper pattern has a high density. As described above, the mixed amphipathic substance has dioctyl phosphate (2C ₈ P having a phosphate group as a hydrophilic group).
OOH) and trioctylmethylammonium chloride (TOMA) having an ammonium group as a hydrophilic group. 2C ₈ POOH is negatively charged in an aqueous solution,
A is positively charged.

Therefore, the membrane (channel 1) in which only 2C ₈ POOH was mixed, the hydrogen ion of tartaric acid (sour taste), N
It responds to both sodium ions of aCl (salt taste). On the other hand, the membrane (channel 4) in which equal amounts of 2C ₈ POOH and TOMA are mixed, has a total surface charge of 0 in an aqueous solution, and therefore only slightly responds to sodium ions. However, since hydrogen ions have adsorptivity, they change the membrane potential. From FIG. 7 (b), the ratio of 2C ₈ POOH and TOMA is (4
7-48): (53-52) shows that an organic film which does not respond to salty taste can be obtained.

The kind and mixing ratio of the bitter substance or the amphipathic substance when an organic film that does not respond to sourness or saltiness is prepared will be described. As can be seen from the examples of 2C ₈ POOH and TOMA, an organic substance that does not respond to salty taste if the bitter substance or amphipathic substance that is negatively charged and the bitter substance or amphipathic substance that is positively charged in the aqueous solution are mixed in equal amounts. It is not possible to make a membrane. For example, a bitter substance or an amphipathic substance is, depending on the type, a ratio (dissociation degree) of an ion in an aqueous solution, a hydrophilic group that binds to the ion of a salty substance per unit amount of the dissociated bitter substance or amphipathic substance. The amount of electric charges of the above, the ease of arranging the bitter substance or the amphipathic substance on the surface of the organic film, etc. Then, the surface charge in the aqueous solution of the organic film is determined by combining these factors. There are reference data as listed in Table 1 regarding whether the bitter substance or amphipathic substance is positively charged or negatively charged in the aqueous solution, but there is no data on other factors. As described above, the optimum mixing ratio will be determined by conducting experiments by changing the mixing ratio of the bitter substance or the amphipathic substance.

In the case of an organic film which does not respond to salty taste,
It suffices if the sum of the surface charges in the aqueous solution of the organic film is zero, but in the case of an organic film that does not respond to sourness, when the substance exhibiting sourness is ionized, hydrogen ions that are cations form a pair. About 100 times stronger than the anion, because it has a stronger bond with the hydrophilic group of the organic film, the bitter substance or the parents should have a positive charge of about 100 for one negative charge of hydrogen ions adsorbed on the surface. The type and mixing ratio of the volatile substance will be selected.

In the above-mentioned embodiments, the present invention is applied to the lipid membrane for a taste sensor of the prior application “Taste sensor and its manufacturing method” (Japanese Patent Application No. 1-190819) of the same applicant as mentioned in the section of the prior art. Although applied, the same applicant's earlier application “Taste sensor and its manufacturing method” (Japanese Patent Application No. 3-020450).
No.) and “sensor” (Japanese Patent Application No. 3-122636).

In addition to the above experiments, the inventors also conducted experiments on reproduction of interactions, and found the following facts. Both produce useful inventions and are disclosed herein. The first thing to consider is the taste of food as perceived by humans. Since the sourness and salty taste are exhibited by the electrolyte, the present taste sensor that measures the potential response is a taste quality that is easy to measure along with bitterness. Therefore, if the quality of a single taste is quantified, the pattern of the multi-channel sensor for the five basic tastes can be quantified by appropriate processing. However, the taste of food that we usually eat is a mixture of different tastes. Taste substances influence each other by mixing, and the taste intensity is different from that when each is taken alone. Such taste interactions have been verified by sensory tests. However, since the cerebrum is quantified by the vague sensation after the final processing, the degree of the interaction has various results obtained by the examination, and there is no general rule.
In other words, some tastes can be used as a guide for single taste, but there is no value or rule to be used as a quantification index for mixed tastes, that is, general foods. Therefore, the taste can be quantified by taking the following steps.

First, since it has been suggested that taste can be measured by a multichannel lipid membrane sensor, first, the behavior of the membrane potential response of this sensor is brought close to the taste receptor response potential of an organism. That is. To do so, we used a lipid membrane prepared by mixing multiple lipids with different characteristics to horse mackerel, and compared the behavior of the membrane potential response with the taste receptor response potential of the organism. This is FIG. 8, and the mixed lipids are azolectin (lecithin extracted from soybean) and 2C ₈ POOH. What was used for comparison was the receptor potential of rat taste cells. From FIG. 8, it can be seen that the membrane used here behaves very similar to the biological system, and the threshold values and the like are almost the same as those of the biological system. Thus, by adjusting the composition of the lipid membrane, the response characteristic of the membrane can be made almost the same as the receptor potential. Here, both are azolectin and 2C ₈ POOH.
It was found that the taste-receiving cells of organisms have a wide variety of receptive properties, and thus it is possible to prepare membranes corresponding to organisms by adjusting the membrane composition. By preparing a large number of lipid membranes with different compositions, it is possible to obtain sensor output patterns that have the same information as the receptor-level taste response patterns of animals other than rats (including humans). .

Second, the acidity (tartaric acid) and saltiness (NaCl) were measured using a membrane in which the mixing ratio of lipids was continuously changed, and the above-mentioned experimental results (FIGS. 7 (a) and 7 (b)). Therefore, the characteristic of sourness is that the channels 1 to 4 have a horizontal straight pattern,
It can be seen that the salty taste has a downward sloping pattern in channels 1-8. By utilizing the characteristics of this pattern, the intensity of sourness or saltiness was calculated. Here, the electric potentials of the channels 1, 4, and 8 are V1, V4, and V8, respectively, and these values represent acidity or saltiness,
The geometric mean of these is tentatively defined as acidity or saltiness. That is, acidity = √ (V1 · V4) ………… (2) Saltiness = √ (V1 · V8) ………… (3). FIG. 9 is an example of a pattern for a mixed solution of tartaric acid (sour taste) and NaCl (salt taste), and when the sourness is obtained using the formula (2), it becomes as shown in FIG. From FIG. 10, when the salty taste is added, the sourness is stronger than when it is alone. This is consistent with the result of a taste interaction in which the sourness and the salty taste are emphasized in human taste. Further, FIG. 11 shows the correspondence between the strengths of various sour substances obtained from the formula (2) and the human sense. From FIG. 11, it can be seen that the sensor and the human sensory value have a one-to-one correspondence, and that this sensor can considerably reproduce the human taste.

[0042]

EFFECTS OF THE INVENTION Focusing on the fact that acidity or saltiness is a taste exhibited by an electrolyte, a bitter substance or amphipathic substance whose hydrophilic group has a positive charge and a bitter substance or parent which has a negative charge in an aqueous solution. A taste sensor and an organic film for a taste sensor in which the charge on the surface was adjusted were obtained by mixing the medium substance with an appropriate ratio. By using these taste sensors or organic films for taste sensors, the amount of information for horse mackerel increases. Especially, it is effective for sweetness that is difficult to measure, and when processing the information of horse mackerel to obtain the strength of each basic taste, use a film insensitive to sourness or saltiness. Thus, for example, the weight of the sweetness term in the simultaneous equation of horse mackerel can be increased to reduce the measurement error of the sweetness intensity.

[0043]

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of an organic film for a taste sensor of the present invention.

FIG. 2 is a schematic view showing a cross section of the taste sensor of the present invention.

FIG. 3 is a schematic diagram showing a cross section of a conventional organic film for a taste sensor.

FIG. 4 is a schematic view showing a cross section of a conventional taste sensor.

FIG. 5 is a schematic view of a taste sensor, (a) is a front view,
(b) is a sectional view.

FIG. 6 is a diagram showing a horse mackerel measurement system.

FIG. 7 is a diagram showing a change in a pattern depending on the density,
(a) is tartaric acid (sour taste), (b) is sodium chloride (sour taste)
FIG. 6 is a diagram showing a change in a pattern depending on the density of.

FIG. 8 is a diagram comparing the potential response of the taste sensor and the potential response of the taste receptor in rat, (a) is hydrochloric acid (sour), and (b) is
Shows the potential response to sodium chloride (salt) and (c) to quinine hydrochloride.

FIG. 9 is a view showing a response pattern to a mixed solution of tartaric acid added to sodium chloride.

FIG. 10 is a diagram showing changes in acidity due to saltiness mixing.

FIG. 11 is a diagram showing a result of comparison between an output of a taste sensor and a human sense value.

[Explanation of symbols]

1 Base Material (Substrate) 2 Electrode 3 Lipid Membrane 4 Buffer Layer 5 Lead Wire 6 Molecular Group of Amphiphile or Bitter Substance 7 Membrane Member 8 Matrix 9 Base Membrane 11 Measured Solution 12 Container 13 Taste Sensor Array 14 Each Lipid Membrane (indicated by black dots) 15 Reference electrode 16 Buffer layer 17 Lead wire 18 Lead wire 19 Buffer amplifier 20 Analog switch 21 A / D converter 22 Microcomputer 23 XY recorder 24 Ground potential 61 Positively charged amphiphilic substance Or molecular group of bitter substance 62 Negatively charged amphiphilic substance or molecular group of bitter substance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 591027765 Kenji Hayashi 3315 Shimoirashi-cho, Kagoshima City, Kagoshima Prefecture 1-503 Iki Higashi Housing (72) Inventor Kaoru Yamato 1-6-21 Kusakoe, Chuo-ku, Fukuoka City, Fukuoka Prefecture (72) Inventor Kiyoshi Toko 2-8-2-2 Miwadai, Higashi-ku, Fukuoka-shi, Fukuoka (72) Inventor Kenji Hayashi 3315 Shimoirashi-cho, Kagoshima-shi, Kagoshima Ishiki Higashi Housing 1-503 (72) Inventor Hidekazu Ikezaki 5-10-10 Minamiazabu, Minato-ku, Tokyo Anritsu Co., Ltd. (72) Inventor Rieko Higashikubo 5-chome 10-27 Minamiazabu, Minato-ku, Tokyo (72) Inventor Katsushi Sato Tokyo Minato-azabu 5-chome 10-27, Anritsu Co., Ltd.

Claims (2)

[Claims] 1. The electrode (2) and the total charge of a hydrophilic part which is fixed to the electrode by covering the entire surface of the electrode in contact with the solution to be measured, and which is directed to the side in contact with the solution to be measured. A taste sensor comprising a plurality of kinds of amphipathic substances or molecular groups (6) of bitter substances whose sum is substantially zero. 2. A film having a matrix on its surface (7)
And a hydrophilic site (a) and a hydrophobic site (b), the hydrophilic site is housed in the matrix of the membrane so that the hydrophilic site is arrayed, and An organic film for a taste sensor, comprising a molecular group (6) of an amphipathic substance or a bitter substance in which the sum of all charges is substantially zero.