Taste presentation device and taste presentation method

Abstract

To provide a taste presentation device that can enhance a taste alteration effect while mitigating unpleasant sensations of a user.SOLUTION: A taste presentation device 10 may have a first electrode 11 and a second electrode 12 provided to allow an electric circuit to be formed between a food or drink to be taken by a user and a body of the user, and an electric stimulus generation unit 13 that supplies a current for generating an electric stimulation between the first electrode 11 and the second electrode 12, the electric stimulus generation unit 13 including noise reduction units 17A, 17B that reduce a noise component in the current.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a taste presentation device that uses electrical stimulation to change the taste perceived by a user. [Background technology]

[0002] For users who are forced to eat bland meals with limited salt and sugar content due to health management or other reasons, methods have been proposed for enhancing the saltiness and other flavors to increase satisfaction by presenting food and drink with modified tastes that match the user's preferences using electrical stimulation. For example, a taste presentation device has been proposed that supplies a square-wave current of a constant frequency between an anode that contacts a body part such as the user's neck and a cathode that contacts the food and drink, thereby enhancing the user's sense of taste (see Patent Document 1). Another device has been proposed that supplies a biphasic current to electrodes placed in contact with the user's tongue or the like to electrically stimulate nerve branches that carry taste sensations to the brain (see Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-42991 [Patent Document 2] Special Publication No. 2010-517675 Summary of the Invention [Problem to be solved by the invention]

[0004] When attempting to use electrical stimulation to enhance or otherwise improve the saltiness of a food, the user may experience some discomfort, such as an excessively pungent sensation or an unnatural metallic taste. If the current value is reduced to avoid such inconveniences, the saltiness enhancement effect may be impaired, and a sufficient improvement effect may not be achieved.

[0005] Therefore, an object of the present invention is to provide a taste presentation device that can enhance the effect of modifying the taste while suppressing the user's sense of discomfort. [Means for solving the problem]

[0006] A taste presentation device according to one embodiment of the present invention comprises a first electrode and a second electrode arranged to form an electrical circuit between the food or drink ingested by a user and the user's body, and an electrical stimulation generating means for supplying a current between the first electrode and the second electrode to generate an electrical stimulation, wherein the electrical stimulation generating means includes a noise reduction means for reducing noise components in the current. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a taste presentation device according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing another example of a taste presentation device. [Figure 3] FIG. 2 is a diagram showing a configuration example of an electrical stimulation generating unit. [Figure 4] FIG. 4 is a diagram showing an example of a current waveform supplied from an electrical stimulation generating unit. [Figure 5] FIG. 10 is a diagram showing another example of a current waveform supplied from the electrical stimulation generating unit. DETAILED DESCRIPTION OF THE INVENTION

[0008] Fig. 1 shows an example of a taste presentation device according to an embodiment of the present invention. The taste presentation device 10 in Fig. 1 includes a first electrode 11 provided to be in contact with a user 1, a second electrode 12 provided to be in contact with food or drink 2 ingested by the user 1, and an electrical stimulation generator 13 as an example of electrical stimulation means that supplies a current between the electrodes 11 and 12 to generate an electrical stimulation.

[0009] The first electrode 11 is attached to the hand or arm of the user 1, for example. A gel-like electrode may be used as the first electrode 11 and attached to the user, or the first electrode 11 may be provided so that the user holds it in their hand. The second electrode 12 is attached to conductive tableware 3 used by the user for eating and drinking. The tableware 3 itself may be used as the second electrode 12. For example, as shown in FIG. 1 , the second electrode 12 may be attached to a stirrer 3 a immersed in a beverage, which is an example of food or drink 2, or the stirrer 3 a itself may be used as the second electrode 12. Alternatively, as shown in FIG. 2 , the second electrode 12 may be attached to a utensil 3 b, such as a fork, spoon, or chopsticks (including so-called cutlery) used to ingest food, which is an example of food or drink 2, or the utensil 3 b may be used as the second electrode 12. In any case, first electrode 11 and second electrode 12 may be configured in any suitable form as long as an electrical circuit is formed between food or drink 2 ingested by user 1 and the body of user 1, thereby allowing a current to flow to electrically stimulate an organ that senses taste, such as the tongue, of user 1. The tableware 3 to which second electrode 12 should be attached is not limited to the examples shown in Figures 1 and 2, and the second electrode 12 may be attached to plates, bowls, rice bowls, rice bowls, bowls, cups, glasses, mugs, sake cups, sake cups, bowls, mugs, teacups, tumblers, water bottles, chopsticks, forks, spoons, knives, spoons, skewers, toothpicks, straws, etc.

[0010] As shown in FIG. 3 , the electrical stimulation generation unit 13 includes a boost circuit 14, a current output unit 15, a current control unit 16, and noise reduction units 17A and 17B (sometimes represented by reference numeral 17). The boost circuit 14 boosts a DC current supplied from an external power source (not shown), for example, via a PC (abbreviation for personal computer) 20, to a predetermined voltage and supplies the boosted voltage to the current output unit 15. The external power source is, for example, an AC commercial power source. The current from the power source is not limited to being supplied via the PC 20, but may also be supplied via a converter such as an appropriate converter or adapter with an AC / DC conversion function. A DC power source such as a battery may also be used as the external power source.

[0011] Current output unit 15 shapes a current waveform according to a command value given by current control unit 16 and supplies the current to electrodes 11, 12. Current control unit 16 is configured as a computer unit using, for example, a microprocessor, and generates a current waveform command value according to current waveform setting information given by PC 20, and controls the current supplied to electrodes 11, 12 by outputting this to current output unit 15. For example, current control unit 16 can control the direction of the current so that anodal stimulation, in which second electrode 12 is the anode, and cathodal stimulation, in which second electrode 12 is the cathode, can be selected, and the magnitude (current value) and rate of change of the current can be controlled to target values ​​given by PC 20. An example of current control will be described later.

[0012] The noise reduction unit 17 reduces noise components contained in the current supplied between the electrodes 11 and 12. The noise reduction unit 17 is an example of a noise reduction means. The inventors' research revealed that noise components contained in the current worsen the stimulating sensation and metallic taste, and that the larger the noise components, the stronger the sense of discomfort. Therefore, by providing the noise reduction unit 17, the impact of minute noise components on the stimulating sensation and metallic taste is suppressed, thereby enhancing the taste modification effect. The term "reduction" refers to a relative reduction in noise components in the current compared to when the noise reduction unit 17 is not provided. It is not limited to cases where some noise components remain, but also encompasses processes such as "removal," "elimination," and "elimination" that reduce noise components to an undetectable level. "Modification" refers to changing the taste perceived by the user 1 from the original taste perceived without the application of electrical stimulation, and "presentation" refers to allowing the user 1 to experience a modified taste.

[0013] The noise reduction unit 17 may be configured by using various elements, such as capacitors, inductors, or ferrite cores, used to reduce noise components in various electrical circuits, either singly or in combination. In the example of Fig. 3, a noise reduction unit 17A is provided on the input side of the boost circuit 14 to reduce noise components originating from an external power supply, and a noise reduction unit 17B is provided on the output side of the boost circuit 14 to remove noise components corresponding to an internal oscillation frequency generated during boosting of the boost circuit 14. However, the positions and number of the noise reduction units 17 may be changed as appropriate depending on the internal configuration of the electrical stimulation generation unit 13, such as the position of a noise source.

[0014] Next, an example of current control by current control unit 16 will be described. Fig. 4 shows an example of a current waveform controlled by current control unit 16, with the horizontal axis representing time and the vertical axis representing current value. The current value is represented by a positive value when second electrode 12 serves as an anode, and a negative value when it serves as a cathode. In the following description, a change in current value, whether positive or negative, will be referred to as an "increase" if the absolute value increases.

[0015] In the example of FIG. 4 , assume that at time t1, user 1 ingests food or drink 2, establishing electrical continuity between electrodes 11 and 12 and forming an electrical circuit including user 1. When the formation of an electrical circuit is detected, current control unit 16 sets the direction of the current to anodal stimulation, i.e., first electrode 11 as the cathode and second electrode 12 as the anode, and begins supplying current. The current value is gradually increased to a set value Is over a predetermined increase time Tx. After reaching the set value Is, current control unit 16 maintains the set value Is for a predetermined retention time Ty, and stops supplying current after the retention time Ty has elapsed. The increase rate (rate of change) of the current value during the increase time Tx is limited to a smaller value than the increase rate when the current value is immediately increased to the set value Is—in other words, the increase rate when the current value is increased at a maximum rate determined by the electrical characteristics of electrical stimulation generation unit 13 without limiting the increase rate of the current value. In this way, by increasing the current value moderately and gradually, it is possible to reduce the sensation of stimulation felt by user 1.

[0016] The set current value Is and the rate of increase in the current value until it reaches the set value Is may be set appropriately depending on environmental conditions such as individual differences among users 1, the degree of the desired taste-modifying effect, or the type of food or drink 2 to be ingested. As an example, the absolute value of the set current value Is may be set to approximately 0.1 mA to 1.0 mA. From the viewpoint of enhancing the taste-modifying effect, the absolute value of the set current value Is is preferably 0.1 mA to 1.0 mA, more preferably 0.3 mA to 1.0 mA, even more preferably 0.5 mA to 1.0 mA, and even more preferably 0.7 mA to 1.0 mA. The rate of increase may be in the range of 0.1 mA / msec or less. When the set current value Is is set to the above-mentioned level, the increase time Tx may be set to at least 0.01 seconds or more, and in some cases may be set to 0.1 seconds or more, or 0.3 seconds or more. The retention time Ty of the set value Is may also be set appropriately depending on environmental conditions such as individual differences between users 1, the degree of the desired taste modification effect, or the type of food or drink 2 to be ingested. As an example, the retention time Ty may be set to about 0.5 seconds.

[0017] FIG. 5 shows another example of a current waveform controlled by the current control unit 16. The horizontal and vertical axes are the same as those in FIG. 4, and the formation of an electrical circuit including the user 1 at time t1 is also the same as in FIG. 4. The example in FIG. 5 differs from the example in FIG. 4 in that both cathodal and anodal stimulation are performed by reversing the polarity of the electrodes 11 and 12 during current supply. That is, in the example in FIG. 5, when the formation of an electrical circuit is detected at time t1, the current control unit 16 sets the current direction to cathodal stimulation, i.e., the first electrode 11 is the anode and the second electrode 12 is the cathode, and begins supplying current. The current value is gradually increased to a set value Is1 over a predetermined increase time Tx1. After reaching the set value Is1, the current control unit 16 maintains the set value Is1 for a predetermined hold time Ty1. After the retention time Ty1 has elapsed, the current control unit 16 changes the direction of the current so that the first electrode 11 becomes the cathode and the second electrode 12 becomes the anode, and increases the current value of the second electrode 12 to a set value Is2 over a predetermined reversal time Tx2. After reaching the set value Is2, the current control unit 16 holds the set value Is2 for a predetermined retention time Ty2, and stops supplying the current when the retention time Ty2 has elapsed.

[0018] As shown in Figure 5, when the polarity is reversed after the start of current supply, the current values ​​Is1 and Is2 are kept relatively small while the polarity reversal is used to fully bring out the taste-changing effect, thereby enhancing the taste-modifying effect. Cathodic stimulation reduces the discomfort felt by the user 1 relatively, but the taste-modifying effect is weak. On the other hand, anodic stimulation increases the taste-modifying effect relatively, but tends to induce a relatively strong sense of discomfort, particularly a metallic taste. Therefore, by first performing cathodic stimulation to reduce the discomfort, and then reversing the polarity to perform anodic stimulation, it is possible to ensure a large change in the current value during reversal, thereby enhancing the taste-modifying effect, while keeping the set value Is2 of the current during anodic stimulation relatively low and suppressing the increase in discomfort.

[0019] In the example of FIG. 5, various parameters defining the current waveform, i.e., the set current values ​​Is1 and Is2, the rate of increase of the current value until the set values ​​Is1 and Is2 are reached, and the duration Ty1 of the cathodic stimulation, may be set appropriately depending on environmental conditions such as individual differences among users 1, the degree of the desired taste-modifying effect, or the type of food or beverage 2 to be ingested. As an example, the absolute values ​​of the set values ​​Is1 and Is2 may be set to approximately 0.1 mA to 1.0 mA. The absolute values ​​of the set values ​​Is1 and Is2 may be equal to or different from each other. From the viewpoint of enhancing the taste-modifying effect, the absolute values ​​of the set values ​​Is1 and Is2 are preferably 0.1 mA to 1.0 mA, more preferably 0.3 mA to 1.0 mA, even more preferably 0.5 mA to 1.0 mA, and even more preferably 0.7 mA to 1.0 mA.

[0020] The rate of increase in the current value during cathodic stimulation until it reaches the set value Is1 can be set to a range of 0.1 mA / msec or less. If the set value Is1 is set to the above-mentioned level, the increase time Tx1 may be set to at least 0.01 seconds or more, and in some cases may be set to 0.1 seconds or more, or even 0.3 seconds or more. The retention time Ty1 of the set value Is1 may be set to, for example, 0.1 seconds or more, and in some cases may be set to 0.3 seconds or more, 0.5 seconds or more, or even 1 second or more. The effect of cathodic stimulation tends to be more easily obtained when the retention time Ty1 is longer.

[0021] The reversal time Tx2 required for the change from the set value Is1 to Is2 may be set to approximately 0.5 seconds or less. If it exceeds 0.5 seconds, the effect of the reversal may not be sufficient. The reversal time Tx2 may be preferably set to 0.4 seconds or less. On the other hand, from the viewpoint of reducing the sensation of stimulation, the reversal time Tx2 may be preferably set to 0.01 seconds or more, more preferably 0.1 seconds or more. The retention time Ty2 of the set value Is2 during anodic stimulation may be set appropriately depending on environmental conditions such as individual differences among the user 1, the degree of the desired taste modification effect, or the type of food or drink 2 to be ingested.

[0022] The current waveforms shown in FIGS. 4 and 5 are merely examples, and the waveform of the current to be supplied between electrodes 11 and 12 may be modified or changed as appropriate. For example, while only anodic stimulation is performed in the example of FIG. 4, only cathodic stimulation may be performed. In the example of FIG. 5, cathodic stimulation is performed first, and then the polarity of electrodes 11 and 12 is reversed to perform anodic stimulation. However, the order may be reversed, with anodic stimulation performed first and then cathodic stimulation. The current waveform may be set taking into consideration various factors, such as the purpose of providing the electrical stimulation, i.e., how the taste should be modified and presented to user 1, the type of food or beverage 2 to be modified, or user 1's preferences and other individual characteristics. In the example of FIG. 4, the rate of increase in the current value during the increase time Tx and the rate of increase in the current value during the increase time Tx1 and the reversal time Tx2 in the example of FIG. 5 are all constant, and the current value changes linearly with a constant slope. However, the current value may change nonlinearly, such as a quadratic curve. Even during the retention times Ty, Ty1, and Ty2, the current value may not be fixed at a constant value but may be varied within an acceptable range. For example, the current waveform may be set to an appropriate waveform, such as a sinusoidal or sawtooth waveform. Even in such cases, it is possible to reduce the sense of discomfort by providing a noise reduction means, and it is possible to reduce the sensation of irritation by increasing the current value relatively gradually. Furthermore, by setting a current waveform with polarity reversal, it is possible to increase the amount of change in the current value while keeping the current value relatively small, regardless of whether cathodic or anodic stimulation is performed first, thereby enhancing the taste modification effect.

[0023] The food and beverages that can be subjected to the taste sensation by the present invention may include various foods and beverages as long as they can pass an electric current to generate an electrical stimulus. Any food and beverage containing water can be subjected to the electric current, but the target foods and beverages are preferably foods and beverages containing 20% ​​or more by weight of water, more preferably 25% or more by weight, and even more preferably 30% or more by weight. The taste-modifying effect can be exerted on various foods and beverages as long as they contain taste components. For example, when enhancing the saltiness of salty foods and beverages, the present invention can be suitably applied to foods and beverages containing 0.05% or more by weight of salt, more preferably 0.1% or more by weight, and even more preferably 0.15% or more by weight of salt. Specific examples of foods and beverages that can be subject to taste modification by the present invention include noodles such as ramen, soups, meat dishes and processed meat products such as sausages and fried chicken, fish dishes and processed seafood products such as grilled fish and fish eggs, egg dishes and processed egg products, tofu dishes and processed tofu products, cheese, cooked and processed foods, vegetable dishes and processed vegetable products, flour dishes, fried foods, hot pots, stews such as curry, alcoholic beverages such as beer and wine, near-water beverages, sports drinks (isotonic drinks), fruit juice drinks, milk beverages, vegetable juice drinks, acidic beverages, carbonated beverages, whey beverages, coffee drinks, black tea drinks, green tea drinks, oolong tea drinks, barley tea drinks, energy drinks, and non-alcoholic beverages such as beer-flavored beverages. The taste that can be modified is not limited to saltiness; various tastes such as sweetness, sourness, umami, bitterness, astringency, stimulating taste, fatty taste, carbonated taste, and alcoholic taste can be modified and presented by the present invention.

[0024] The taste (e.g., salty) enhancement effect, the intensity of the stimulating sensation, and the metallic taste in the present invention can be easily and clearly determined by a trained panelist. The evaluation criteria and the method for summarizing the panelists' evaluations can be general methods. The number of panelists evaluating the taste (e.g., salty) enhancement effect, the intensity of the stimulating sensation, and the metallic taste in the present invention may be one. However, from the viewpoint of obtaining a more objective evaluation, the lower limit of the number of panelists can be, for example, two or more, preferably three or more. Furthermore, from the viewpoint of more easily conducting the evaluation test, the upper limit of the number of panelists can be, for example, 20 or less, or 10 or less. When there are two or more panelists, the evaluation of the taste (e.g., salty) enhancement effect, the intensity of the stimulating sensation, and the metallic taste of the food or beverage sample may be performed by using the average of the evaluations of all panelists regarding the taste (e.g., salty) enhancement effect, the intensity of the stimulating sensation, and the metallic taste of the food or beverage sample. When an integer score is assigned to each evaluation criterion, the average of the scores of all panelists may be used to evaluate the taste (e.g., saltiness) enhancement effect, the intensity of the stimulating sensation, and the metallic taste. As described above, when the average of the evaluation scores is used, the average may be rounded to the nearest tenth or tenth place (preferably the nearest tenth). When there are two or more panelists, it is preferable to standardize the evaluation criteria so that the evaluation criteria of each panelist are as consistent as possible before conducting the actual sensory evaluation test in order to reduce the variability in the evaluations of each panelist. Such standardization may involve having each panelist evaluate the taste intensity or the intensity of the stimulating sensation and metallic taste for multiple food and beverage samples known to have a taste (e.g., saltiness) enhancement effect, and then comparing the evaluation scores to ensure that there is no significant discrepancy between the evaluation criteria of each panelist. Furthermore, by standardizing the evaluation criteria in advance, when evaluation points are given on one of multiple levels (for example, one of five levels: 1, 2, 3, 4, and 5), it is preferable to ensure that the standard deviation of each panelist's evaluation of the taste (for example, saltiness) enhancement effect, stimulating sensation, and metallic taste intensity is within 0.5. [Example]

[0025] Next, a test conducted to confirm the effects of the present invention will be described. The test conditions are as follows.

[0026] (1) Test conditions [Equipment used] Device 1: A device with electrodes configured as shown in Figure 1 and an electrical stimulation generator configured as shown in Figure 3. However, a 100V AC commercial power supply was used as the external power source, which was converted to 20V, 2.25A DC by an AC adapter and supplied to the boost circuit. Device 2: Device 1 in which the electrodes were converted to the configuration shown in Figure 2. Device 3: A device that omits the noise reduction section compared to Device 1. Device 4: A device that omits the noise reduction section compared to Device 2. In all of Devices 1 to 4, the first electrode was a monitoring electrode 2560 (trade name "Reddat" (registered trademark) manufactured by 3M Japan Ltd.). The first electrode was attached to the subject's hand. The second electrode was an electrode that could be attached to the connection target, such as a clip-on electrode, and was directly connected to conductive tableware. Regarding the noise reduction section, noise reduction section 17A, which aims to reduce noise components originating from the external power source, used an inductor manufactured by Murata Manufacturing Co., Ltd., part number LQM21PN4R7MGRD. For noise reduction section 17B, which corresponds to the internal oscillation frequency of the boost circuit, an inductor of the MLZ2012 type manufactured by TDK Corporation, part number MLZ2012N101LT000, was used.

[0027] [Food and drink samples] The following food and drink samples were prepared: Tasting samples: Based on the salt concentrations of regular to lightly seasoned soups, salt solutions with salt concentrations of 0.3% by weight and 0.5% by weight were prepared as tasting samples. Tasting sample: Based on the salt concentration of regular to lightly seasoned baked foods prepared at home, a salt-water agar gel with a salt concentration of 0.6% by weight (agar concentration 0.8% by weight) was prepared and cut into 1 cm cubes to be used as tasting samples. General food samples: Commercially available sports drinks, instant egg soup, instant miso soup, fish sausage, salad chicken, and cup noodles were used. The cup noodles were diluted twice to give a lighter flavor.

[0028] [Test method] Four subjects were selected based on their ability to distinguish between salty taste intensities at a salt concentration of 0.03% by weight through a preliminary test. Each subject ingested food and beverage samples using Devices 1-4 as appropriate. To reduce variability in the evaluations of each subject, prior to the actual sensory evaluation test, each subject rated the salty taste enhancement effect, the intensity of the stimulating sensation, and the metallic taste of several known food and beverage samples, or the intensity of the stimulating sensation and metallic taste when electrodes presenting several electrical stimulation conditions with known intensities of the stimulating sensation and metallic taste were placed on the tongue. The evaluation scores were then compared to ensure there was no significant discrepancy between the evaluation criteria of each subject. Furthermore, it was confirmed that the standard deviation of each subject's evaluation of the salty taste enhancement effect, the intensity of the stimulating sensation, and the metallic taste was within 0.5. During ingestion, a taste stimulation current was supplied between the electrodes from the electrical stimulation generator, and each subject was asked to assign scores to the salty taste enhancement effect, stimulating sensation, and metallic taste according to the criteria in Tables 1 to 3 below to obtain a sensory evaluation. The evaluation results were then calculated by rounding the average of all subjects' evaluation scores to the nearest tenth. Regarding current control, tests were conducted for a case in which only anodic stimulation was performed (example in Figure 4), a case in which only cathodic stimulation was performed (corresponding to the waveform in Figure 4 flipped upside down), and a case in which cathodic stimulation was performed first and then reversed to anodic stimulation, as shown in Figure 5. The increase time Tx and retention times Ty and Ty1 shown in Figures 4 and 5 were also appropriately changed to confirm their effects.

[0029] [Table 1]

[0030] [Table 2]

[0031] [Table 3]

[0032] For the salty taste enhancement effect in Table 1, a score of 3 or more was evaluated as "effective," and for the stinging sensation in Table 2 and the metallic taste in Table 3, a score of 3 or less was evaluated as "no problem." In the test results shown below, cases in which the salty taste enhancement effect was evaluated as 3 points or more and the stinging sensation and metallic taste were evaluated as 3 points or less are considered examples, and test results that do not fit this category are shown as comparative examples.

[0033] (2) Confirmation of noise reduction effect With reference to Table 4, tests conducted to confirm the influence of noise reduction on salty taste enhancement effects, etc., will be described. Examples 1 to 12 in Table 4 show evaluation results when either Device 1 or Device 2, which includes a noise reduction unit, was used and current was supplied between the electrodes to provide either anodic or cathodic stimulation. Comparative Examples 1 to 4 show evaluation results when either Device 3 or Device 4, which does not include a noise reduction unit, was used and current was supplied between the electrodes to provide either anodic or cathodic stimulation.

[0034] [Table 4]

[0035] The "electrical stimulation conditions" in Table 4 indicate whether anodic or cathodic stimulation was performed, the current setting value, and the current retention time at the setting value. For example, in Example 1, anodic stimulation at 0.3 mA and retention time of 0.5 seconds indicates that the anodic stimulation shown in Figure 4 was performed, with a setting value Is of 0.3 mA and a retention time Ty of 0.5 seconds. Examples 1 to 9 are examples in which electrical stimulation was applied to a tasting sample using Device 1, while Examples 10 and 11 are examples in which electrical stimulation was applied to a tasting sample using Device 2. The current increase time Tx was set to 0.01 seconds in all Examples 1 to 11. The setting value Is was set to 0.3 mA (Examples 1 and 5), 0.5 mA (Examples 2, 6, 8 to 11), 0.7 mA (Example 3), or 1.0 mA (Example 4), so the current increase rate during the increase time Tx was in the range of 0.03 mA / ms to 0.1 mA / ms. On the other hand, Comparative Examples 1 to 4 are examples using Device 3 or Device 4 that does not have a noise reduction unit. The food and drink samples and electrical stimulation conditions for Comparative Example 1 are the same as those for Example 1, Comparative Example 2 is the same as those for Example 4, Comparative Example 3 is the same as those for Example 7, and Comparative Example 4 is the same as those for Example 10.

[0036] As is clear from Table 4, Examples 1 to 11, in which noise reduction was implemented, were confirmed to provide appropriate evaluations of the salty taste enhancement effect, stimulating sensation, and metallic taste, regardless of whether anodic or cathodic stimulation was used. On the other hand, Comparative Examples 1 to 4, in which noise reduction was not implemented, were only evaluated as inadequate, even though the electrical stimulation conditions were the same as those of the corresponding Examples 1, 4, 7, and 10. In particular, sufficient effects were not obtained with respect to stimulating sensation or metallic taste.

[0037] (3) Confirmation of the effect of polarity reversal

[0038] Tests conducted to confirm changes in the salty taste enhancement effect, etc., due to electrode polarity reversal will be described with reference to Table 5. Examples 12 to 22 in Table 5 show the evaluation results when Device 1 was used for the tasting sample and Device 2 was used for the food sample, and cathodic stimulation was performed first in accordance with the current waveform in Figure 5, and then the direction of the current was reversed and anodic stimulation was performed.

[0039] [Table 5]

[0040] The "electrical stimulation conditions" in Table 5 show the settings of the set values ​​Is1 and Is2 and the holding times Ty1 and Ty2 in FIG. 5. For example, in Example 12, the set value Is1 of the current value during cathodal stimulation is −0.7 mA, and the holding time Ty1 is 1.0 second, and the set value Is2 of the current value during anodal stimulation is +0.7 mA, and the holding time Ty2 is 0.5 second. The correspondence between the samples and anodal stimulation conditions of Examples 12 to 22 and the samples and anodal stimulation conditions of Examples 1 to 11 in Table 4 is as follows: Example 12 corresponds to Example 3, Examples 13 to 17 correspond to Example 4, Example 18 corresponds to Example 2, Example 19 corresponds to Example 1, Example 21 corresponds to Example 8, and Example 21 corresponds to Example 9. Example 20 is an example in which the retention time Ty2 of anodal stimulation was set to the same as in Example 19, while the set current value Is2 was further reduced from 0.3 mA to 0.1 mA. The increase time Tx1 of the current value when starting cathodal stimulation was 0.01 seconds, and the increase rate was in the same range as Examples 1 to 11 in Table 4. Furthermore, the reversal time Tx2 was set to 0.1 seconds or less in all of Examples 12 to 22.

[0041] When the evaluation results were compared according to the above-described correspondence, all but Example 14 were confirmed to be further improved compared to the evaluation results of the Examples shown in Table 4. For example, Example 3 received ratings of "4, 1, 2" for the salty taste enhancement effect, spiciness, and metallic taste, while Example 12 received ratings of "5, 1, 1," demonstrating improvements in the salty taste enhancement effect and metallic taste. Furthermore, it was also confirmed that when polarity reversal was performed, the overall flavor of the food and beverage sample was enhanced, resulting in a reduction in the metallic taste compared to when anodic stimulation was performed alone. Note that Example 14 received a rating similar to that of when anodic stimulation was performed alone. This may be due to the extremely short retention time of cathodic stimulation (0.01 seconds), which may have prevented the full effect of prioritizing cathodic stimulation. Therefore, it is recommended that cathodic stimulation be maintained for at least 0.01 seconds as a minimum guideline. On the other hand, as is clear from Example 20, when polarity reversal was performed, the salty taste enhancement effect was enhanced compared to Example 1, despite the low current setting value of 0.1 mA during anodic stimulation. From this point of view, it can be seen that polarity reversal is an effective means of increasing the effect of improving taste while keeping the set current value low.

[0042] (4) Confirmation of the effect of the type of food and drink Tests conducted to confirm differences in salty taste enhancement effects, etc. depending on the type of food and drink will be described with reference to Table 6. Table 6 shows the results of evaluating the salty taste enhancement effects, etc., by selectively using Apparatus 1 to Apparatus 4 on various general food samples instead of tasting or eating samples.

[0043] [Table 6]

[0044] In Table 6, Examples 23 to 42 show the evaluation results when either anodic or cathodic stimulation was performed alone, following the current waveform in Figure 4, or when cathodic stimulation was performed first, followed by anodic stimulation, following the current waveform in Figure 5. Comparative Examples 5 to 12 show the evaluation results when either anodic or cathodic stimulation was performed alone, using either Device 3 or Device 4, which do not include a noise reduction unit, or when cathodic stimulation was performed first, followed by anodic stimulation. The type of general food sample and electrical stimulation conditions for each example are as shown in Table 6. Table 6 also lists representative comments from the subjects. Note that the current increase time when anodic stimulation was performed alone or when cathodic stimulation was performed first was 0.01 seconds, and the increase rate was within the same range as Examples 1 to 11 in Table 4. Furthermore, the reversal time when polarity reversal was performed was 0.1 seconds or less, as in the examples in Table 5. When instant egg soup and instant miso soup were used as general food samples, the samples were taken without using a straw, but by directly drinking from the container containing the sample.

[0045] The results in Table 6 confirm that Examples 23 to 42, which included noise reduction, demonstrated improved effects in suppressing discomfort compared to Comparative Examples 5 to 12, which omitted noise reduction for the same samples. The effects of noise reduction were particularly pronounced with respect to stinginess and metallic taste. For example, comparing Example 23 with Comparative Example 5, the stinginess rating improved from "4" to "1," and the metallic taste rating improved from "5" to "1." Furthermore, when polarity reversal was performed, further improvements were observed regardless of the type of general food sample compared to when anodal or cathodal stimulation was performed alone. For example, comparing Example 23 with Example 25, or Example 29 with Example 31, the salty taste enhancement rating improved from "4" to "5," despite the current setting during anodal stimulation being reduced from 1.0 mA to 0.5 mA. In these comparisons, the retention time of anodal stimulation differed, with the retention time being longer when polarity reversal was performed. However, when comparing Example 40 and Example 42, it can be seen that, even though the anodic stimulation retention time of Example 42 is 0.3 seconds, which is shorter than the 0.5 second retention time of Example 40, Example 42 is rated as having a higher salty taste enhancement effect at the same current value. Therefore, it is presumed that the presence or absence of polarity reversal has a relatively greater impact on the taste-modifying effect than the length of the retention time during anodic stimulation. From the comments of the subjects, it can also be confirmed that an overall flavor enhancement was observed in many Examples.

[0046] (5) Confirmation of the effect of different current increase rates Tests conducted to confirm the influence of differences in the rate of increase in current value during current supply on the salty taste enhancement effect, etc., will be described with reference to Table 7. Table 7 shows the results of evaluating the salty taste enhancement effect, etc., using commercially available fish sausage as a general food sample and using Apparatus 2 as Examples 43 and 44. Commercially available fish sausage was selected as the sample because it was determined to be suitable for confirming the effect of suppressing the irritation sensation, since food has a lower water content than beverages and the irritation sensation upon ingestion tends to be more pronounced in foods.

[0047] [Table 7]

[0048] Example 43 in Table 7 performs only anodic stimulation, and the electrical stimulation conditions are the same as those of Example 29, which uses the same sample, except that the increase time until the current value reaches the set value of 1.0 mA is changed to 0.1 seconds (0.01 seconds for Example 29). Example 44 performs only cathodic stimulation, and the electrical stimulation conditions are the same as those of Example 30, which uses the same sample, except that the increase time until the current value reaches the set value of 1.0 mA is changed to 0.1 seconds (0.01 seconds for Example 30). As is clear from the comparison between Example 29 and Example 43, and between Example 30 and Example 44, it can be confirmed that the sensation of stimulation is further weakened in Examples 43 and 44, which have relatively long increase times.

[0049] Various aspects of the present invention derived from the above-described embodiments, modifications, and examples will be described below. In the following description, to facilitate understanding of each aspect of the present invention, corresponding components shown in the accompanying drawings will be written in parentheses, but this does not mean that the present invention is limited to the illustrated forms.

[0050] A taste presentation device (10) according to one embodiment of the present invention comprises a first electrode (11) and a second electrode (12) arranged to form an electrical circuit between a food or drink (2) ingested by a user (1) and the body of the user, and an electrical stimulation generating means (13) for supplying a current to generate an electrical stimulation between the first electrode and the second electrode, the electrical stimulation generating means including a noise reducing means (17A, 17B) for reducing noise components in the current.

[0051] According to the inventor's research, when modifying taste using electrical stimulation, it has been found that noise components contained in the current can cause the stimulating sensation and metallic taste to worsen, and the larger the noise components, the stronger the sense of discomfort tends to become. Therefore, by reducing the noise components in the current supplied between the electrodes using noise reduction means, it is possible to suppress the effect of the noise components on the stimulating sensation and metallic taste and enhance the desired taste modification effect.

[0052] In the above aspect, the electrical stimulation generating means may change the direction of the current so that the polarity of the first electrode and the second electrode is reversed after the supply of the current is started. When the polarity is reversed while the current is being supplied to generate the electrical stimulation, the absolute value of the current value can be kept relatively small, while the amount of change in the current value at the time of polarity reversal can be increased, thereby effectively eliciting a taste-modifying effect.

[0053] The electrical stimulation generating means may start supplying the current in a state of cathodic stimulation in which the second electrode is the cathode, and then change the direction of the current so as to switch to a state of anodic stimulation in which the second electrode is the anode. Cathodic stimulation tends to reduce the user's discomfort but have a weak taste-modifying effect, while anodic stimulation tends to increase the taste-modifying effect but induce a relatively strong discomfort, particularly a metallic taste. Therefore, by first performing cathodic stimulation to reduce discomfort, and then reversing the polarity to perform anodic stimulation, it is possible to ensure a large change in current value during reversal to enhance the taste-modifying effect, while keeping the current setting value for anodic stimulation relatively low to prevent an increase in discomfort.

[0054] The electrical stimulation generating means may change the direction of the current so that the cathodic stimulation is applied for a retention time (Ty1) of 0.1 seconds or more while maintaining a predetermined current setting (Is1), and the anodic stimulation is applied after the retention time. By setting the retention time of the cathodic stimulation within the above range, it is possible to enhance the effect of prioritizing the cathodic stimulation.

[0055] The electrical stimulation generating means may change the direction of the current so that the polarity reversal is completed within a reversal time (Tx2) of 0.5 seconds or less, thereby effectively achieving the effect of the polarity reversal.

[0056] The electrical stimulation generating means may gradually increase the current value at the start of supplying the current while limiting the rate of change of the current value to 0.1 mA / msec or less. By increasing the current value while limiting the rate of change of the current value to the above range, it is possible to prevent a deterioration in the sensation of stimulation that would otherwise accompany a sudden increase in the current value, and to reliably bring about a modifying effect such as taste enhancement.

[0057] The first electrode may be disposed in contact with the user's body, and the second electrode may be disposed in contact with the food or drink. By disposing the electrodes in this manner, an electrical circuit can be formed between the food or drink and the user's body when the food or drink is ingested.

[0058] The noise reduction means (17A) may be provided to reduce noise components originating from a power source. When the electrical stimulation generating means includes a boost circuit (14), the noise reduction means (17B) may be provided to reduce noise components corresponding to an internal oscillation frequency of the boost circuit. These configurations make it possible to effectively reduce noise components that cause a worsening of the stimulating sensation and metallic taste. [Explanation of symbols]

[0059] 10 Taste presentation device 11 1st electrode 12 Second electrode 13 Electrical stimulation generating unit (electrical stimulation generating means) 14 Boost circuit 17A, 17B Noise reduction unit (noise reduction means)

Claims

1. a first electrode and a second electrode provided so as to form an electrical circuit between the food or drink ingested by the user and the user's body; an electrical stimulation generating means for supplying a current between the first electrode and the second electrode to generate an electrical stimulation; The taste presentation device, wherein the electrical stimulus generating means includes noise reducing means for reducing noise components in the current.

2. The taste presentation device according to claim 1 , wherein the electrical stimulation generating means changes the direction of the current so that the polarities of the first electrode and the second electrode are reversed after the supply of the current starts.

3. The taste presentation device described in claim 2, wherein the electrical stimulation generating means starts supplying the current in a state of cathodic stimulation in which the second electrode is the cathode, and then changes the direction of the current so that it switches to a state of anodic stimulation in which the second electrode is the anode.

4. The taste presentation device described in claim 3, wherein the electrical stimulation generating means changes the direction of the current so that the cathodic stimulation, maintaining a predetermined current setting value, is carried out for a holding time of 0.01 seconds or more, and after the holding time, the anodic stimulation is carried out.

5. 5. The taste presentation device according to claim 2, wherein the electrical stimulation generating means changes the direction of the current so that the polarity reversal is completed within a reversal time of 0.5 seconds or less.

6. A taste presentation device described in any one of claims 1 to 5, wherein the electrical stimulation generating means gradually increases the current value so that the rate of change of the current value is limited to 0.1 mA / msec or less when the supply of the current begins.

7. The taste presentation device according to any one of claims 1 to 6, wherein the first electrode is provided so as to be in contact with the user's body, and the second electrode is provided so as to be in contact with the food or drink.

8. 8. The taste presentation device according to claim 1, wherein the noise reduction means is provided to reduce noise components originating from a power source.

9. A taste presentation device as described in any one of claims 1 to 8, wherein the electrical stimulation generating means includes a boost circuit, and the noise reduction means is configured to reduce noise components corresponding to an internal oscillation frequency in the boost circuit.

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