JPH08285813A - Measuring method of taste - Google Patents

Abstract

PURPOSE: To provide the measuring method, of a taste, which increases the quantity of information on the taste and which can discriminate a measuring object in which the taste is hard to discriminate. CONSTITUTION: A reference solution is prepared (S1), and a prescribed additive is added to a solution to be measured (S2). The reference solution is measured, a reference value V01 is found (S3, S4), the solution to be measured is measured (S5), and the difference ΔVi between the measured value Vi of the solution to be measured and the reference value V01 (S6). Then, a sensor is cleaned in order to perform a measurement again (S7).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a difference in taste of food or drink by using a sensor capable of substituting the taste which is one of the five senses of a human being, and more particularly to a conventional method. The present invention relates to a horse mackerel measuring method capable of identifying even a slight difference in taste, which was difficult to identify by the measuring method.

[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 First, a technique for measuring horse mackerel will be described. Techniques for measuring horse mackerel include, for example, Japanese Patent Laid-Open No. 62-
As described in Japanese Patent No. 187252, the concentration of each original taste (basic taste) component, that is, the selected taste substance in the measurement object is calculated from the output values of a plurality of taste sensors, and each concentration value is adjusted according to the taste of a person. There is a method in which horse mackerel is measured by correcting the value to represent the intensity of the original 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, 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 to chemical substances, for example, a salt concentration meter that is trying to measure the strength of saltiness can measure the concentration of salt (NaCl), but cannot measure the concentration of other substances that exhibit salty taste. However, there was a limit even if it was corrected to match the taste of people. By analogy with color, it was like trying to obtain color results using a sensor that senses only a single color.

The applicant of the present application, in collaboration with others, applied for a patent for "a taste sensor and its manufacturing method" (Japanese Patent Application No. 1-1908).
19), and in the specification and drawings, a lipid substance composed of molecules having a hydrophobic portion and a hydrophilic portion is fixed in a polymer matrix, and the hydrophilicity of the lipid molecule is It was shown that the lipidic molecular film, which has a structure in which the parts are aligned, can be a taste sensor, that is, a taste sensor that can replace the human taste.

FIG. 10 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 31 is partly dissolved in the matrix 33 (surface structure, microscopic structure having a planar spread) on the surface of the membrane member 32 (eg It is accommodated at 31 ') in FIG. The way it is stored is such that hydrophilic sites are arranged on the surface.

FIGS. 11 (a) and 11 (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, the substrate has 0.5
A silver round bar was inserted into the hole of mmφ and used as an electrode. A lipidic molecular film (hereinafter also referred to as a lipid film or a molecular film) is attached to a base material so as to come into contact with an electrode via a buffer layer.

FIG. 12 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 4 | lipid membrane 3 (14) |
Solution to be measured 12 ｜ Buffer layer (potassium chloride 100m mole / l)
16 | Silver chloride 4 | 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 8-channel taste sensor is used, and each channel has different response characteristics to taste in order to obtain a large amount of taste information capable of reproducing the taste of human being. It is composed of a molecular film.

[0009]

[Table 1]

The taste sensor referred to in the above specification is just a taste sensor, and has physicochemical properties close to those of the tongue, which is the taste organ of human being, and the same taste is obtained even if different taste substances are used. You can get output, and you can get some output for different tastes. For example, this is a sensor that can detect color.

As a method of measuring horse mackerel using this taste sensor, the applicant of the present invention has jointly filed a patent application for "horse mackerel detecting method" (Japanese Patent Laid-Open No. 4-064053). With the present invention, it is possible to identify even minute differences in horse mackerel, such as differences in brands of foods such as beer and lots. The outline is described below. In order to detect and measure horse mackerel with a taste sensor using lipidic molecules with good reproducibility, a reference solution close to the sample liquid to be measured is used, and the taste sensor is sufficiently immersed in the reference solution, A similar stimulus is applied to the taste sensor for each measurement, and the measurement time is selected after the surface potential has stabilized and when the internal potential changes slowly.Here, the difference between the measured values of the reference solution and the sample solution to be measured is I decided to calculate. If the object to be measured is beer, beer or a substance close to beer is used as a reference liquid, the taste sensor is immersed in the reference liquid in advance, and the taste sensor is soaked in the reference liquid. As a result, an adsorbent substance is adsorbed in advance on the lipid film contained in beer, and the influence of the adsorbent substance is reduced when various beers are measured. Although it has low sensitivity to a substance that is adsorbable to the lipid membrane, it has the effect of greatly improving reproducibility.

As a more advanced detection method of the above "horse mackerel detection method", a patent application for "horse mackerel detection method" (Japanese Patent Application No. 4-349688) was filed by some of the applicants of the present application. According to the horse mackerel detection method of the first aspect of the invention, the taste sensor using a molecular film of an amphipathic substance or a bitter substance (hereinafter referred to as a molecular film) can detect and measure horse mackerel with good reproducibility. As the first standard solution and the second standard solution, those close to the sample solution are used, and the first standard solution (V0) →
The second reference solution (Vk)-> the first reference solution (V0 ')-> the sample solution (Vs) is measured in this order, and the relative value of the sample solution measured value from the reference value {(Vs-V0')-(Vk- V0)} is eliminated to eliminate the variation in the relative value in the continuous drift of the taste sensor, and by using the first reference liquid, even if the taste of the first reference liquid changes, the influence on the measurement value is affected. lost.

[0013]

As described above, the method for measuring horse mackerel using a taste sensor using a molecular film improves reproducibility and increases the amount of information. It can be said that it can also be said that the resolution of horse mackerel is improved.), Etc. have been variously devised. However, depending on the measurement target, there are still some that are difficult to identify, even though there are differences in horse mackerel. Moreover, although it is a measurement target that can be tentatively identified by using the conventional measurement method, if the amount of information can be increased by the new measurement method, the horse mackerel can be identified from another direction (viewpoint). An object of the present invention is to improve the technique for measuring horse mackerel and increase the amount of information about the horse mackerel. It is possible to identify a measurement object that was difficult to identify with the conventional technology. It is to provide a measurement method.

[0014]

[Means for Solving the Problems] A predetermined additive according to the object to be measured is added to the solution to be measured, and the measurement is performed. That is, as one step of the measurement, a step of adding a predetermined additive to the solution to be measured was provided before the measurement. And
A step of preparing a reference solution, a step of adding a predetermined additive to the solution to be measured, a step of measuring the reference solution using the taste sensor to obtain a reference value, and a step of obtaining the reference value using the taste sensor. The method comprises the steps of measuring a measurement solution and obtaining a measured value, and calculating a difference between the reference value and the measured value. If the measurement target is coffee, the predetermined additive is milk, skim milk, or the like.

[0015]

By adding a predetermined additive according to the object to be measured to the solution to be measured, the response of the taste sensor (hereinafter, also referred to as a sensor) to the solution to be measured changes, and is obtained when it is not added. Information on horse mackerel that cannot be obtained.

[0016]

Embodiments of the present invention will be described below. Figure 1
It is a figure which shows the flow of a measurement of one Example of this invention. It will be described with reference to FIG. S1 Prepare standard solution. S2 Add a predetermined additive to the solution to be measured. S3 Measure the sensor potential of the reference liquid. S4 Compared with the sensor potential of the reference liquid measured one time before, if the range of change is within the set value, it is considered to be stable, and the process proceeds to S5 to measure the sensor potential of the sample. If the change width is equal to or larger than the set value, the process returns to S3. This means that the influence of putting in and taking out the sensor is checked, and the operation of putting in and taking out the sensor is periodically performed until the influence is eliminated. Finally set the stable sensor potential of the reference solution to V
Set to 01 (reference value). S5 sensor is stable, sample (solution to be measured)
The sensor potential Vi (measurement value) of Si is measured. The measurement result .DELTA.Vi = Vi-V01 of the S6 sample Si is calculated. S7 Wash sensor. This is again S for the next measurement.
This is to prevent the reference solution from being contaminated with the measured solution adhering to the sensor when performing step 3. Specifically, the same liquid as the reference liquid is prepared, and the sensor is put in and taken out of the liquid. After that, if the sample is measured continuously, S3
Go to. In this embodiment, the sensor potential is measured as the reference value and the measured value, but the current, the resistance, etc. may be measured.

[Experiment 1] Instant coffee was measured using the measuring method of the present invention and the conventional measuring method. The measurement and the result will be described. The taste sensor used for the measurement consists of 7 types of sensors of 7 channels (hereinafter abbreviated as ch), and the lipids contained in the molecular membrane of each ch are shown in Table 2. There are 9 brands (A, B,
C, D, E, F, G, H, I). The solution to be measured is
Each brand was prepared by dissolving 2 ml of powdered or granular coffee in 140 ml of pure water. Coffee I (brand) was used as a standard solution.

[0018]

[Table 2]

(A) Measurement by the conventional measuring method Measuring procedure After the sensor is put into and taken out from the reference solution 5 times, the measurement is carried out. Repeated several times, the difference from the previous measured value is 0.5m
When it becomes V or less, the last measured value is set as the reference value V01. After the sensor is put in and taken out from the solution to be measured Si five times, the measurement is performed to obtain the measured value Vi. The measurement result ΔVi = Vi−V01 of the solution to be measured Si is calculated. The same solution as the standard solution is prepared in two separate beakers, and the sensor is taken out and put in to wash the sensor 25 times in the first beaker and then 15 times in the second beaker. To each measured solution coffee A, B, C, D,
Perform E, F, G, and H. The above measurement of coffee A to H is set as one time, and this is repeated five times.

FIG. 2 is a radar chart showing the average of the five measured values measured as described above.
Since the measured value is a relative value with coffee I as the reference liquid, the measured value of coffee I is 0. The unit of the scale of the radar chart is mV. The same applies to the scales of other radar charts described later.

In FIG. 3, the average of each of the five measured values is 0,
The results are obtained by normalizing so that the variance becomes 1, and performing a principal component analysis. From this result, except for the coffee F and the coffee I, the difference between the measured values of each coffee is sufficiently large compared to the error of the five measurements, and the brands can be easily identified.
The contribution rate (PC1) of the first principal component is 95.8%, and the contribution rate (PC2) of the second principal component is 2.2%.

Table 3 shows the measured values of the five times and coffee A to
Between each channel and each c calculated from pH value of I
It is a correlation coefficient between h and pH. Correlation is high between almost all channels, and each channel is highly correlated with pH. From this, it can be said that the first main component almost represents sourness. Therefore, it is difficult to distinguish between the coffee F and the coffee I having a close pH.

[0023]

[Table 3]

(B) Measurement by the measuring method of the present invention Before the measurement, each solution to be measured (coffee A to I) was
Milk added as a predetermined additive and skimmed milk added as a predetermined additive were respectively prepared. The amount to be added is 140 ml of coffee, 10 ml of milk and 1.
It is 2 g. The reference solution is Coffee I as described above.
(No addition). The subsequent measurement procedure is the same as the above-mentioned measurement procedures 1 to. However, coffee I (addition) is also measured.

FIG. 4 (a) shows the case where milk is added, FIG.
(B) is a radar chart showing the average of five measurements for each of those to which skim milk was added. The measured value is a relative value using Coffee I (no addition) as a reference solution. Table 4 shows the correlation coefficient between each channel when milk was added, and each channel and pH, and Table 5 shows the correlation coefficient between each channel when skim milk was added and between each channel and pH. . In both Table 4 and Table 5, the correlation between ch3 and other channels is lower than that in Table 3 which is the result measured by the conventional measurement method. From this, 7
One channel is divided into two groups, ch3 and other channels.

[0026]

[Table 4]

[0027]

[Table 5]

FIG. 5 (a) shows the results obtained by the conventional measuring method described above.
The results of normalization and principal component analysis for a total of 3 channels of ch3, ch5, and ch7 from the measured values of the times (Note that in FIG.
(h1 to ch7 results of normalization and principal component analysis for all ch), FIG. 5 (b) is a result of normalization and principal component analysis for a total of 3 ch3, ch5, and ch7 from the measured values of five times when milk was added. Fig. 5 (c) shows ch3, ch5, c from the measured values of 5 times measured by adding skim milk.
It is the result of normalizing the principal component analysis for a total of 3 channels of h7. When milk is added (FIG. 5B), the contribution ratio of the first main component is 76.8%, and the contribution ratio of the second main component is 22.2.
It became%. When skim milk is added (Fig. 5)
In (c), the contribution rate of the first principal component was 89.8%, and the contribution rate of the second principal component was 8.6%. When the milk is added, the contribution ratio of the second main component is based on the conventional measurement method (see FIG. 5).
It increased to about 6 times the contribution rate of the second principal component in (a)). In FIG. 5A, the horse mackerel information is almost one-dimensional, and it is difficult to distinguish between the coffee F and the coffee I. on the other hand,
In FIG. 5B and FIG. 5C, the horse mackerel information spreads two-dimensionally, making it easy to distinguish between the coffee F and the coffee I.

[Experiment 2] Next, in order to investigate a subtle difference in taste of coffee, the components such as acid contained in the coffee were selected, and the horse mackerel was measured using the measured solutions having different amounts of the components. It was The measurement results obtained by the measurement method of the present invention and the measurement results obtained by the conventional measurement method are also shown and described. The taste sensor used for the measurement is composed of 7 types of 7 kinds of sensors, and the lipids contained in the taste sensor membrane of each channel are shown in Table 2.
It is as follows. The coffee used in the experiment is Coffee I described above. As the solution to be measured, 11 samples were prepared by adding one kind of each of the coffee components shown in Table 6 to 100 g of a powder or granular coffee I dissolved in 2 ml of pure water 140 ml. Table 6
However, except for d (malic acid), i (trigonelline) and j (chlorogenic acid), the amounts are contained in 100 g of the average coffee extract. Therefore, the concentration of the components after adding those components is about twice the concentration before the addition. Coffee I was used as a standard solution.

[0030]

[Table 6]

(A) Measurement by the conventional measurement method The measurement procedure is the same as the above-mentioned measurement procedures 1 to. However, the solution to be measured is the 11 samples. FIG. 6 is a radar chart showing the average of five measurements. The measured value is a relative value with coffee I as the reference liquid. FIG. 7 shows the result of normalizing the measurement values of 5 times and performing the principal component analysis. The contribution rate of the first principal component is 99.6%, the contribution rate of the second principal component is 0.2%, and the information is almost one-dimensional.
That each channel of the sensor has a high correlation with pH (Table 3),
Table 6 lists the pHs after addition of the respective components, and it can be said that the first main component almost represents the pH because the samples having the same pH are plotted at almost the same positions. As described above, according to the conventional measurement method, it is possible to identify the intensity of sourness, but it is difficult to identify the subtle difference in taste due to the difference in the type of acid. For example, it is difficult to identify the sample a, the sample e, the sample f, the sample b, the sample c, and the sample i.

(B) Measurement by the measuring method of the present invention Before the measurement, each solution to be measured (samples a to k) was
Milk added as a predetermined additive and skimmed milk added as a predetermined additive were respectively prepared. The amount to be added is 140 ml of coffee, 10 ml of milk and 1.
It is 2 g. The reference solution is Coffee I as described above.
(No addition). The subsequent measurement procedure is the same as the above-mentioned measurement procedures 1 to.

FIG. 8 (a) is a product to which milk is added, (b)
Is a radar chart showing the average of 5 measurements for each of those with skim milk added. The measured value is a relative value using Coffee I (no addition) as a reference solution. Table 7 shows the correlation coefficient between each channel when milk was added and each channel and pH, and Table 8 shows the correlation coefficient between each channel when skim milk was added and between each channel and pH. . In both Table 7 and Table 8, as compared with Table 3 which is the result measured by the conventional measurement method, ch3 and other channels are compared.
The correlation with is low. From this, 7 channels
Are divided into two groups, ch3 and other channels.

[0034]

[Table 7]

[0035]

[Table 8]

FIG. 9 (a) shows the results obtained by the conventional measurement method described above.
The result of normalization and principal component analysis for a total of 3 channels of ch3, ch5, and ch7 from the measured values of the times (note that FIG.
(h1 to ch7 results of normalization and principal component analysis for all ch), FIG. 9 (b) is a result of normalization and principal component analysis for a total of 3 ch3, ch5, and ch7 from the measured values of five times when milk was added. FIG. 9 (c) shows ch3, ch5, c from the measured values of 5 times measured by adding skim milk.
It is the result of normalizing the principal component analysis for a total of 3 channels of h7. In FIG. 9A by the conventional measurement method, the contribution ratio of the first principal component is 99.3%, and the contribution ratio of the second principal component is 0.5%.
Is. In the case of the conventional measurement method, since the correlation of all 7 channels is high, even if the number of channels is reduced, the change of each contribution rate is small compared with the result shown in FIG. When milk was added (FIG. 9B), the contribution rate of the first main component was 98.6%, and the contribution rate of the second main component was 1.2%. When skim milk was added (FIG. 9C), the contribution ratio of the first main component was 90.1% and the contribution ratio of the second main component was 9.7%. The contribution rate of the second main component when skim milk was added was significantly increased as compared to the case where the conventional measurement method was used (FIG. 9A). In FIG. 9A, the horse mackerel information is almost one-dimensional, and it is difficult to identify the sample b, the sample c, and the sample i. On the other hand, in FIGS. 9B and 9C, the horse mackerel information spreads two-dimensionally, which facilitates the identification of the sample b, the sample c, and the sample i. In the above experiment, milk and skim milk were used as additives, but when the solution to be measured is coffee, creaming powder, cream or the like may be used.

As shown by the results of Experiments 1 and 2, by using the horse mackerel measuring method of the present invention, it is possible to discriminate a delicate taste which was difficult with the conventional measuring method. This is an increase in the amount of information on horse mackerel and also an improvement in the resolution of the horse mackerel measurement.

[0038]

According to the horse mackerel measuring method of the present invention, a predetermined additive corresponding to the object to be measured is added to the solution to be measured, and the measurement is carried out. Now, it has become possible to identify subtle differences in taste, which were difficult to identify with the conventional technology.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of measurement according to an embodiment of the present invention.

[FIG. 2] Coffee A, B, C, D, and
It is a radar chart which shows the result of having measured E, F, G, and H.

[FIG. 3] Coffees A, B, C, D by conventional measurement methods
It is a figure which shows the result of normalizing the measured value of E, F, G, H, and I, and performing the principal component analysis.

FIG. 4 shows coffee A, B, C, by the measuring method of the present invention.
It is a radar chart which shows the result of having measured D, E, F, G, H, and I, (a) is a radar chart when milk is added, and (b) is a radar chart when skim milk is added.

FIG. 5: Coffee A, B, C, D, E, F, G, H, I
It is a figure which shows the result of normalizing the measured value of, and (a) is ch3, ch5, ch by the conventional measuring method.
The figure which shows the result of having normalized the measured value of 7 and carrying out the principal component analysis,
(B) is c when the additive is milk by the measuring method of the present invention
The figure which shows the result of having normalized the measured value of h3, ch5, ch7, and having shown the result of having carried out the principal component analysis, (c) normalized the measured value of ch3, ch5, ch7 when skim milk was used as the additive by the measuring method of this invention. It is a figure which shows the result of component analysis.

FIG. 6 is a radar chart showing the results of measurement of 11 coffee samples in which different coffee components were added by a conventional measurement method.

FIG. 7 is a diagram showing the results of normalization and principal component analysis of the measured values of 11 coffee samples in which different coffee components were added according to the conventional measurement method.

FIG. 8 is a radar chart showing the results of measuring 11 samples of coffee with different amounts of coffee components increased by the measurement method of the present invention, (a) is a radar chart when milk is added, and (b) is skim milk. It is a radar chart in the case of adding.

FIG. 9 is a diagram showing the results of normalization and principal component analysis of the measured values of 11 coffee samples in which different coffee components were added, and (a) shows ch3 and c by the conventional measurement method.
The figure which shows the result of having normalized the measured value of h5, ch7, and having shown the result of having carried out the principal component analysis, (b) normalizing the measured value of ch3, ch5, ch7 when the additive was milk by the measuring method of this invention, and principal component analysis. The figure showing the results, (c) shows ch3, ch5, ch when the additive is skim milk in the measuring method of the present invention.
It is a figure which shows the result of having normalized the measured value of 7 and carrying out the principal component analysis.

FIG. 10 is a schematic diagram showing a lipid membrane by an expression method used in a chemical substance designing method.

FIG. 11 is a schematic view of a taste sensor, (a) is a front view,
(b) is a sectional view.

FIG. 12 is a diagram showing a horse mackerel measurement system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Electrode 3 Lipid membrane 4 Buffer layer 5 Lead wire 11 Solution to be measured 12 Container 13 Taste sensor array 14 Each lipid membrane (indicated by a black dot) 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 31 Lipid molecule group 31 'Lipid molecule group 32 Membrane member 33 Matrix

Claims (1)

[Claims] 1. A method of measuring the horse mackerel of a solution to be measured using a taste sensor using a molecular film of an amphipathic substance or a bitter substance, which comprises a step of preparing a reference solution (S1), A step of adding a predetermined additive to the measurement solution (S2), and a step of measuring the reference solution using the taste sensor to obtain a reference value (S3, S).
4), measurement of the solution to be measured using the taste sensor to obtain a measurement value (S5), and step of calculating a difference between the reference value and the measurement value (S6). Law.