JP4974383B2 - Evaluation method for flavor improvers - Google Patents

Description

  The present invention relates to a method for evaluating an appropriate concentration of a taste substance and a flavor improving agent. More specifically, multiple tasting substance aqueous solutions with different concentrations are prepared, each subject is allowed to drink each sample, the cerebral blood flow change at that time is measured, and the appropriate concentration of the gustatory substance is evaluated based on the response intensity of the cerebral blood flow change In addition, a flavor improving agent is further added to a taste substance aqueous solution having a specific concentration selected from a concentration lower than or higher than the appropriate concentration, and a plurality of samples having different flavor improving agent concentrations are added. The present invention relates to a method of adjusting, allowing a subject to drink each aqueous solution, measuring a change in cerebral blood flow at that time, and evaluating an appropriate concentration of the flavor improving agent based on a response intensity of the change in cerebral blood flow.

  As a method for evaluating the flavor of food and drink, sensory evaluation based solely on human senses is heavily used. Sensory evaluation is suitable for comprehensive evaluation, but has the disadvantage that subjective factors such as individual differences, sensory fatigue, and changes in physical condition are affected. The QDA method (quantitative description analysis method) is a method that gives objectivity to the subjective evaluation, but it takes time to select common terms and train the panel.

  In addition, various chromatographs including liquid chromatographs, and evaluations by devices such as odor sensors and taste sensors are used. Although evaluation using an instrument such as a liquid chromatograph is objective, analysis for each target item is required, and it takes a considerable amount of time to perform a comprehensive evaluation. A sensor that substitutes human sense of smell and taste has a short measurement time, but has a problem in stability, reproducibility, and correlation with sensory evaluation by a subject.

  Therefore, in order to make the subjective evaluation by humans objective, it has been attempted to adopt a psychophysiological method for observing and measuring physiological responses occurring in the living body in addition to these. Psychophysiology is a psychological study that studies the state and movements of the heart using the indicators of biological responses that can be measured, such as pupil size, heart rate, blood pressure, brain waves, magnetoencephalogram, cerebral blood flow, and stress hormone concentrations. This is a new area. Humans show physiological responses such as changes in blood pressure, heart rate, and stress substances in saliva as well as changes in sensations and emotions by smelling. Observation and measurement of these physiological responses is a method for evaluating flavor from an angle different from conventional instrumental analysis and sensory evaluation, and is a new method for evaluating flavor.

  Capillaries are densely present in the cerebral cortex, the place where most emotional information is finally received, the place of computation processing, and the place where the corresponding output is directed, and the hemoglobin in the blood tends to absorb near infrared rays It has the nature of If this is used to irradiate near-infrared rays onto the scalp to detect reflected light, the blood flow in the cerebral cortex can be determined, and in turn the state of its activity.

  Non-Patent Document 1 discloses an apparatus (hereinafter referred to as an optical topography apparatus) that measures the amount of hemoglobin using near infrared rays. In this measuring apparatus, near infrared rays (NIR) in a specific wavelength region are incident from one side of the subject's head using an optical fiber. Part of the near-infrared light incident on the subject's head is absorbed by the tissue in the head, and the remaining part is detected by a detector on the scalp via the cerebral cortex. The absorptance in the subject's head is measured by measuring the intensity of the detected near infrared ray. The optical topography apparatus has an advantage that it is not large and restrictive like positron emission tomography (PET method) and functional magnetic resonance imaging (fMRI method).

  Non-Patent Document 2 discloses which part of the brain is active by monitoring the brain activity when performing a sensory evaluation of the flavor of tea using an optical topography device.

Journal of the Institute of Electrical Engineers of Japan, Vol. 123, no. 3, 2003, pages 160-163 Appitete, Vol. 7, 2006, 220-232

  The present invention solves the drawbacks based on sensory evaluation, etc., uses the optical topography device described above, adjusts multiple tastant aqueous solutions with different concentrations, allows the subject to drink each sample, and changes the cerebral blood flow at that time A method of measuring and evaluating an appropriate concentration of a gustatory substance according to a response intensity of a change in cerebral blood flow, and a tastant aqueous solution having a specific concentration selected from a concentration lower than or higher than the appropriate concentration, Add flavor improver, adjust multiple samples with different flavor improver concentration, make each subject drink each aqueous solution, measure cerebral blood flow change at that time, according to the response intensity of cerebral blood flow change, It aims at providing the method of evaluating the appropriate density | concentration of a flavor improving agent.

  The inventors of the present invention focused on the above characteristics of the optical topography device, and used the optical topography device to examine changes in cerebral blood flow when eating or drinking a taste substance or a food or drink containing a flavor improver. Measures and uses the fact that the change in cerebral blood flow tends to decrease due to its adaptability when drinking the same sample continuously, and based on the measurement results, the taste or taste of the flavor improver is selected. Disclosed is a method for improving the flavor of a substance or food and drink (Japanese Patent Laid-Open No. 2007-252350).

  In addition, the present inventors have determined whether the amount of change in cerebral blood flow when eating or smelling a scented food or drink is appropriate for the imitation flavor relative to the target flavor (“no discomfort” ”,“ Reliability ”,“ Nature ”,“ Familiarity ”,“ Familiarity ”, etc.) (Japanese Patent Application No. 2007-227994).

  However, in Japanese Patent Application Laid-Open No. 2007-252350 and Japanese Patent Application No. 2007-227994, there is a detailed correspondence between the concentration of taste substances and the response intensity of cerebral blood flow, or between the intensity of taste and the response intensity of cerebral blood flow, It was not possible to elucidate the detailed correspondence between the intensity of the flavor and the response intensity of the cerebral blood flow when a flavor improver was added to the taste substance and the flavor was functionally modified.

  The present inventors thought that it would be possible to measure the effect of the concentration of the sample solution on the odor or taste that influences the flavor using an optical topography apparatus, and as a result of intensive studies, the brain at the time of drinking the sample solution after drinking this time The amount of change in blood flow varies depending on the concentration of the sample solution, and the suitability of the sample solution concentration in odor and taste (hereinafter sometimes referred to as flavor) is evaluated by measuring the amount of change in cerebral blood flow. As a result, the present invention has been completed.

  That is, the present invention adjusts a plurality of gustatory substance aqueous solutions having different concentrations, causes the subject to drink each sample, measures the change in cerebral blood flow, and determines the appropriate concentration of the gustatory substance based on the response intensity of the blood flow change. It provides a way to evaluate.

  In addition, the present invention further adds a flavor improver to a specific concentration of a taste substance aqueous solution selected from a concentration lower than or higher than the above-mentioned appropriate concentration, and samples having different flavor improver concentrations are added at that time. A method is provided in which a plurality of adjustments are made, a subject is allowed to drink each aqueous solution, a change in cerebral blood flow at that time is measured, and an appropriate concentration of the flavor improving agent is evaluated based on a response intensity of the change in cerebral blood flow.

  Furthermore, the present invention provides a method for evaluating an appropriate concentration of the above-mentioned taste substance, or an appropriate concentration of a flavor improving agent for a specific concentration of an aqueous taste substance solution, wherein the cerebral blood flow is a blood flow of the cerebral cortex. It is to provide.

  Furthermore, in the present invention, the change in cerebral blood flow is measured by measuring the change in the amount of hemoglobin in the blood by near-infrared spectroscopy. A method is provided for evaluating the proper concentration of a flavor improver.

  In the present invention, the appropriate concentration of the tastant described above, wherein the cerebral blood flow change is a change in cerebral blood flow in the outer frontal region of the cerebrum, or the appropriate concentration of the flavor improving agent with respect to a specific concentration of the tastant aqueous solution, A method of evaluating can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the flavor evaluation method which can evaluate efficiently and objectively the appropriate density | concentration of the flavor improving agent with respect to the appropriate density | concentration of a gustatory substance and the gustatory substance aqueous solution of a specific density | concentration can be provided.

  In the present invention, a subject is allowed to drink a taste substance aqueous solution or a solution obtained by adding a taste improver to a taste substance aqueous solution, and the change in cerebral blood flow at that time is measured to obtain an appropriate concentration of the taste substance or a taste substance having a specific concentration. Evaluate the appropriate concentration of the flavor improver for the aqueous solution. The appropriate concentration of the tastant is a concentration having a desired sensory strength. In addition, the optimal concentration of the flavor improving agent can be sensed by the sensory flavor intensity at the optimal concentration of the taste substance by adding to the concentration of the taste substance below or above the optimal concentration of the taste substance. The concentration of the flavor improver. It can be evaluated that the strength of the flavor is stronger as the response strength of the change in cerebral blood flow is higher, and the strength of the flavor is weaker as the response strength is lower.

  Drinking the sample aqueous solution and measuring changes in cerebral blood flow are performed as follows. The subject is kept in a resting state. First, water is put in the mouth, water is spread throughout the mouth, swallowed 30 seconds after being put in the mouth, and then rested for 60 seconds. Next, the sample solution is put in the mouth, the sample solution is thoroughly tasted in the mouth, swallowed 30 seconds after the sample solution is put in the mouth, and then rested again for 60 seconds. Next, water is again put into the mouth, water is spread throughout the mouth, swallowed 30 seconds after being put in the mouth, and then rested for 60 seconds. Then, another sample solution is put in the mouth, the sample solution is thoroughly tasted in the mouth, swallowed 30 seconds after the sample solution is put in the mouth, and then rested again for 60 seconds. Thus, drinking of water and drinking of the sample solution are repeated alternately. The sample can be performed about 4 to 5 points in one experiment. Pre-selected 4 to 5 samples are evaluated sequentially according to the above procedure. While evaluating these samples, measure cerebral blood flow, including drinking and resting times, and record the changes. The sensory evaluation is carried out for 30 seconds while the sample is contained in the mouth, and after the evaluation of a series of 4 to 5 points is completed, the sensory evaluation is entered at the end with respect to the strength of the flavor of the sample.

  When the sample solution is ingested in such a procedure, the cerebral blood flow gradually increases in the outer frontal portion of the cerebrum after being included in the mouth, and the cerebral blood flow reaches a maximum between about 5 seconds to about 30 seconds. Indicates the value. Thereafter, the cerebral blood flow gradually decreases, and returns to the original level in about 60 seconds after being put in the mouth. Therefore, from the “maximum value” of cerebral blood flow from about 5 seconds to about 30 seconds after inclusion in the mouth in a specific brain region, the “minimum” of cerebral blood flow from the moment of inclusion in the mouth to about 15 seconds. The value obtained by subtracting “value” is defined as the response intensity of cerebral blood flow change. This time, it has been found that this response intensity agrees very well with the intensity of sensual taste at specific brain sites. Therefore, by using a plurality of subjects and averaging the concentration of the gustatory substance aqueous solution corresponding to the obtained taste intensity, it is possible to evaluate the general appropriate concentration of the specific gustatory substance aqueous solution. Conceivable.

  The flavor evaluation method of the present invention can be performed by measuring a change in cerebral blood flow using an optical topography device attached to a subject when the subject is performing sensory evaluation of the aqueous taste substance solution. The appropriate concentration of the gustatory substance aqueous solution can be evaluated by statistically processing the cerebral blood flow data of each channel (CH) of the optical topography apparatus. Examples of the optical topography apparatus used in the present invention include a Hitachi ETG-4000 type optical topography apparatus (manufactured by Hitachi Medical Corporation: 52 channels).

  As the brain region for measuring the response intensity of the change in cerebral blood flow, the outer frontal portion of the cerebrum can be used. In this part, there is a tendency that a positive correlation is found between the taste intensity and the response intensity. When the Hitachi ETG-4000 optical topography device is used, the response to changes in cerebral blood flow in the outer frontal region of the cerebrum is channel 8, 9, 10, 18, 19, 20, 21, 29, 30, 31, 39 in the left brain. , 40, 41, 42, 50, 51, 52, and in the right brain, channels 1, 2, 3, 11, 12, 13, 14, 22, 23, 24, 32, 33, 34, 35, 43, 44, 45. Of these channels, the channels 33, 34, 44, 40, 41, and 51 are particularly preferable.

  As a general relationship between the concentration of the taste substance aqueous solution and the strength of taste, when the concentration of the taste substance is taken on the horizontal axis and the sensory score is taken on the vertical axis, the concentration increases and the sensory score also increases. There is a tendency to rise to the right.

  In the present invention, under the measurement conditions described above, the response intensity of cerebral blood flow change has a positive correlation with the intensity of taste, and the response of cerebral blood flow change is measured. It was found that the proper concentration of can be evaluated.

  In the present invention, the taste substance is not particularly limited, and examples include tastes such as sweet taste, sour taste, bitter taste, umami taste, and pungent taste. Specific examples of these taste substances include sugar. Saccharides such as licorice, licorice extract, stevia extract, rakanka extract and the like, or artificial sweeteners such as aspartame, sucralose, and acesulfame potassium. Examples of sour substances include organic acids contained in lemons, etc., and examples of bitter substances include hop extract (humulones), caffeine, quina extract (kinin), naringin, theobromine, nigaki extract, sagebrush extract , Use in foods such as gentian extract, medicinal bitter substances, alkaloids, etc. And food-containing substances such as polyphenols (catechin, isoflavone, chlorogenic acid). Among the fragrance ingredients, menthol, mint oil and the like have a bitter taste in the aftertaste. Examples of umami substances include nucleic acids such as inosinic acid and guanylic acid, and amino acids such as glutamic acid, alanine, glycine and arginine. Examples of pungent substances include capsaicin in chili pepper, piperine in pepper, 6 in ginger. -Gingerol etc. can be mentioned.

  The present invention also provides a method for improvement by adding some flavor improver to an aqueous solution having a concentration lower than or higher than the appropriate concentration of the aqueous taste substance solution. For example, in the development of beverages, the sugar concentration is set lower than the most preferred flavor for the purpose of reducing the sugar intake in order to reduce calories and supplemented with sugar flavor, and the salt intake in the soup is reduced. For this purpose, it is set to a concentration lower than the salt concentration, which is the most preferable concentration in terms of flavor, and supplemented with a salty enhancer.

The flavor improving agent is not particularly limited as long as it is a substance that exhibits a synergistic effect on the taste substance. For example, the flavor improving effect by the flavor, the taste of the light sweetness sweetener by the flavor such as sugar flavor. Improvement effect, synergistic effect of umami substances by combining amino acid and nucleic acid seasoning, masking effect of bitterness by flavor, masking effect of bitterness and astringency by sweetener, light sweetness level by combined use of light sweetness degree sweetener Examples include the effect of eliminating the disadvantages of sweeteners, the effect of enhancing the salty taste by acid, and the effect of enhancing the salty taste by flavoring.
For example, when a flavor improver having a flavor enhancing effect is added to an aqueous taste substance solution below the appropriate concentration, the concentration of the flavor improver is taken on the horizontal axis, and the sensory score is taken on the vertical axis, the concentration of the flavor improver There is a so-called upward trend that increases with increasing sensual scores.

In the present invention, under the measurement conditions described above, the response intensity of cerebral blood flow change has a positive correlation with the intensity of taste in sensory evaluation, and cerebral blood flow change is measured. It has been found that the appropriate concentration of the improver can be evaluated.
The following examples further illustrate the present invention.

(Example 1) Examination of taste intensity and brain activity of a taste substance aqueous solution exhibiting a basic taste In this example, a subject is allowed to drink a representative basic taste sweet taste and sour taste taste substance having different concentrations. Then, we measured changes in cerebral blood flow at that time, and examined how the cerebral blood flow in the outer frontal region of the cerebrum changes.
A sample, a subject, a measuring device, and a measuring method are shown below.
[sample]
Sample 1: Aqueous sugar solution: 0%, 2%, 4%, 6%, 8%
Sample 2: Aspartame aqueous solution: 0%, 0.012, 0.024%, 0.036%, 0.048%
Sample 3: Aqueous citric acid solution: 0%, 0.01%, 0.05%, 0.1%
[subject]
10 randomly selected subjects (men and women in their 20s to 50s)
[measuring device]
Hitachi ETG-4000 optical topography system (manufactured by Hitachi Medical Corporation: 52 channels)
[Measuring method]
A probe equipped with a number of sensors connected to an optical topography apparatus was mounted on the subject's head, and each sample was swallowed for measurement. After resting according to the time schedule shown in FIG. 1, water was first drunk and then the sample was drunk to positively evaluate the flavor. The drinking order of the samples was performed from the low concentration side to the high concentration side for one type of taste substance aqueous solution. The sensory evaluation was performed according to the evaluation table shown in FIG. 2, with the taste strength being 0: tasteless, 3: weak, 6: normal, 9: strong, 12: very strong.
[result]
FIG. 3 shows typical oxygenated hemoglobin in channel 52, which is a representative measurement point of the outer frontal cerebrum, when water is first drunk and then the sample is drunk. A graph of the amount of change over time is shown. In the figure, 0 to 90 seconds are responses to water, and 90 to 180 seconds are responses to the sample. The response intensity was defined as “(maximum value of cerebral blood flow for 5 to 30 seconds) − (minimum value of cerebral blood flow for 0 to 15 seconds) when the instruction to start drinking is 0 second”.

(1) Sensory Evaluation of Sample Concentration and Taste Strength Each of the taste strength items in the sensory evaluation of sugar concentration 0-8%, aspartame concentration 0-0.048%, citric acid concentration 0-0.1% The evaluation result that the taste became stronger as the concentration became higher was obtained. Further, a positive correlation (R = correlation coefficient) was observed between the sample concentration and the taste intensity, and the relationship between the average value of the sample concentration and the taste intensity showed good linearity (R ² value: Sugar 0.99, aspartame 0.96, citric acid 0.91).

(2) Relationship between sample concentration and response intensity In the relationship between sample concentration and response intensity, it was affected when the sugar concentration was 0-8%, the aspartame concentration was 0-0.048%, and the citric acid concentration was 0-0.1%. There was a tendency for the response intensity to increase as the sample concentration increased on the outer frontal side. In addition, a positive correlation (R = correlation coefficient) is observed between the sample concentration and the response intensity, and the average value of the change in cerebral blood flow in the channel 41, which is a representative measurement point in the outer frontal region of the cerebrum, is observed. This relationship showed good linearity (R ² value: sugar 0.99, aspartame 0.83, citric acid 0.90).
FIG. 4 shows the relationship between the intensity of these sensual tastes and the response intensity of changes in cerebral blood flow in the channel 41, which is a representative measurement point in the outer frontal region of the cerebrum. A positive correlation (R = correlation coefficient) was found between the intensity of the taste and the response intensity, and the relationship between the average values of the ^two showed a good linearity (R ² value: sugar 0.97, aspartame 0) .94, citric acid 0.99).

(3) Response site in cerebral cortex region The cerebral cortex region where the above-mentioned tendency is detected is the outer frontal portion of the cerebrum, and in the left brain, channels 8, 9, 10, 18, 19, 20, 21, 29, 30, 31, 39, 40, 41, 42, 50, 51, 52 and in the right brain, channels 1, 2, 3, 11, 12, 13, 14, 22, 23, 24, 32, 33, 34, 35, In 43, 44, and 45, a positive correlation was found between the taste intensity and the response intensity in the sensory evaluation of the sample. As an example, the correlation coefficient (R) between the strength of the taste and the response intensity in each channel when using an aqueous sugar solution as a sample is shown in FIG. There is a correlation between taste intensity and response intensity in the vicinity of the channel corresponding to the outer frontal part of the cerebrum, and channels with correlation coefficient (R)> 0.4 that are generally considered to have a correlation are channels 19 and 20. , 21, 29, 30, 31, 39, 40, 41, 42, 51, 52, 12, 23, 33, 34, 35, 43, 44, 45, which corresponds to the outer frontal region of the cerebrum.
Based on the above, the response intensity of changes in cerebral blood flow when a subject was given a tasting substance aqueous solution with a different concentration showed a strong positive correlation with the intensity of the taste felt by the subject, and this was an evaluation of the appropriate concentration of the tasting substance. It is thought that the result of being effective was shown.

(Example 2) Examination of a sample solution obtained by adding a flavor improving agent to a taste substance aqueous solution and brain activity In this example, as a taste substance aqueous solution having a specific concentration selected from a concentration lower than the appropriate concentration selected in Example 1 A 2% sugar aqueous solution was selected. Furthermore, various concentrations of ethyl maltol (a sugar flavor, which is thought to have a sweetening effect) were added as flavor improvers, and the subjects were allowed to drink their respective aqueous solutions. Was measured, and the appropriate concentration of the flavor improving agent was evaluated based on the response intensity of changes in cerebral blood flow.
[sample]
Sample 4: Sugar 2% aqueous solution + ethyl maltol (0 ppm, 0.05 ppm, 10 ppm, 20 ppm)
[subject]
10 randomly selected subjects (men and women in their 20s to 50s)
[measuring device]
Hitachi ETG-4000 optical topography system (manufactured by Hitachi Medical Corporation: 52 channels)
[Measuring method]
In the same manner as in Example 1, the five samples were subjected to sensory evaluation in order from the one with the smallest amount of ethyl maltol added according to the time schedule shown in FIG. 1, and entered in the sensory evaluation table shown in FIG.
[result]
FIG. 6 shows the relationship between the strength of the taste and the response intensity in a 0-8% aqueous sugar solution, and the intensity of the taste and the response intensity when ethyl maltol was added to a 2% aqueous sugar solution at a concentration of 0.05-20 ppm. Show the relationship.

(1) Sensory Evaluation of Ethylmaltol Concentration and Taste Strength When increasing the concentration of ethylmaltol from 0.05 to 20 ppm in an aqueous solution of 2% sugar, the sensory sweetness intensity increases as the concentration increases. There was a tendency to increase.

(2) Relationship between ethyl maltol concentration and response intensity It was confirmed that the ethyl maltol concentration and the response intensity showed a positive correlation in the left and right frontal lateral areas with increasing ethyl maltol concentration. That is, the sample in which ethyl maltol was added to a 2% sugar aqueous solution was larger than the 2% sugar aqueous solution alone, and a result suggesting that a synergistic effect due to the integration of taste and odor occurred.
As described above, the subject further adds a flavor improving agent having a different concentration to the tastant aqueous solution having a specific concentration selected from a concentration lower than the appropriate concentration, and causes the subject to drink each aqueous solution. It is considered that the response intensity of the change in cerebral blood flow when measuring the change was effective in evaluating the appropriate concentration of the flavor improving agent.

  From the above results, it was found that the brain activity in the outer frontal region of the cerebrum depends on the taste and smell that make up the flavor. It can be confirmed that the cerebral blood flow in the outer frontal region of the cerebrum increases depending on the concentration of sweetness and sourness, and the change in cerebral blood flow when a sugar solution with a sweet smell is ingested changes with sugar alone. Larger than that, it was possible to measure that the focused brain activity was also changed by the smell, and that the taste response was modified by the smell.

It is explanatory drawing which shows the time schedule when experiment is implemented. It is a sensory evaluation sheet when an experiment was conducted. It is a figure which shows the time-dependent change amount of the typical oxygenated hemoglobin after drinking the sample after water in the cerebral front side lateral part (channel 52). Changes in cerebral blood flow and sensory strength of 0-8% sugar aqueous solution, 0.006-0.048% aspartame aqueous solution and 0-0.4% citric acid aqueous solution in the lateral frontal region of the cerebrum (channel 41) It is a figure which shows the relationship with a response strength. Of the 52 channels, channels 19, 20, 21, 29, 30, 31, 39, 40, 41, 42, 51, 52, 12, 23, 33, 34, 35, 43 corresponding to the outer frontal region of the cerebrum 44, 45, the correlation coefficient (R)> 0.4 between the strength of the taste of the sugar sample and the response intensity when the sugar sample is drunk, indicating that a correlation is observed. The relationship between the sensory taste intensity of 0-8% aqueous sugar solution and the response intensity of changes in cerebral blood flow in the lateral frontal region of the cerebrum (channel 41), and 0.05% ethyl maltol in 2% aqueous sugar solution It is a figure which shows the relationship between the intensity | strength of the sensory taste when added by a 20 ppm density | concentration, and the response intensity | strength of a cerebral blood flow change.

Claims (5)

(1) a step of adjusting a plurality of taste substance aqueous solutions having different concentrations;
(2) letting the subject drink each sample, and measuring the change in cerebral blood flow at that time;
(3) a step of measuring the strength of taste by sensory evaluation,
(4) Taste intensity by sensory evaluation , left brain channel 8, 9, 10, 18, 19, 20, 21, 29, 30, 31, 39, 40 , 41, 42, 50, 51, 52, right brain channel 1 , 2, 3, 11, 12, 13, 14, 22, 23, 24, 32, 33, 34, 35, 43, 44 and 45, the step of associating the response intensity of the change in cerebral blood flow at any one point selected from Including,
(5) a method of evaluating the concentration of taste substances strength of taste becomes proper by sensory evaluation.
(1) A sample having a different flavor-improving agent concentration is further added to a taste substance aqueous solution having a specific concentration selected from the concentration lower than or higher than the appropriate concentration according to claim 1. Multiple adjustments,
(2) A step of allowing a subject to drink each aqueous solution and measuring a change in cerebral blood flow at that time,
(3) a step of measuring the strength of taste by sensory evaluation,
(4) Taste intensity by sensory evaluation , left brain channel 8, 9, 10, 18, 19, 20, 21, 29, 30, 31, 39, 40 , 41, 42, 50, 51, 52, right brain channel 1 , 2, 3, 11, 12, 13, 14, 22, 23, 24, 32, 33, 34, 35, 43, 44 and 45, the step of associating the response intensity of the change in cerebral blood flow at any one point selected from Including,
(5) a method of evaluating the concentration of flavor improver strength of taste becomes proper by sensory evaluation.
Cerebral blood flow, method better according to claim 1 or 2, characterized in that a blood flow in the cerebral cortex.
Cerebral blood flow change, method better according to any one of claims 1 to 3, the change in hemoglobin and measuring by near-infrared spectroscopy in blood.
Method person according to any one of claims 1 to 4, wherein the cerebral blood flow rate change is cerebral blood flow changes in the cerebral frontal outer portion.

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