Bitterness enhancer

Abstract

To provide a novel bitterness enhancer, a novel bitterness-enhancing flavoring composition, and a novel method for enhancing bitterness of food and beverages.SOLUTION: A bitterness enhancer comprises, as an active ingredient, a compound represented by a following formula (1) [where: R1 is a C1-3 linear or branched alkyl group or a hydroxyl group; and R2 is a 1-pyrrolyl group, 2-pyrrolyl group, or 3-pyrrolyl group]. A bitterness-enhancing flavoring composition contains the bitterness enhancer. A method for enhancing the bitterness of food and beverages comprises the step of adding the bitterness enhancer or the bitterness-enhancing flavoring composition to food and beverages.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a bitterness enhancer for foods and beverages. [Background technology]

[0002] There are five main tastes: sweet, sour, salty, umami, and bitter. Of these, bitterness is often perceived as a signal of poison from plants and other substances, and is generally avoided. Bitterness can cause an unpleasant taste when present in excess in food and drink, but when present in moderate amounts, it often gives food and drink a good flavor, such as depth and richness. Examples of such foods include coffee, chocolate, and beer, all of which are considered to be characteristic tastes of highly palatable foods.

[0003] As an example of imparting bitterness to foods and beverages, Patent Document 1 describes a bitterness imparting agent added to a beer-flavored beverage. The bitterness imparting agent in Patent Document 1 includes hop-derived components, quasin, naringin, wormwood (or wormwood extract or wormwood flavoring), citrus extract, bitter perilla extract, coffee extract, tea extract, bitter melon extract, lotus germ extract, aloe arborescens extract, rosemary extract, lychee extract, laurel extract, sage extract, caraway extract, isohumulones, and reduced isohumulones. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 193675 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the bitterness imparting agents proposed so far impart bitterness as a taste, and do not fully meet the demand for improving the flavor of foods and beverages, which are becoming more and more diverse. Therefore, the present inventors focused on the bitterness sensation as a flavor, rather than the bitterness as a taste itself, and developed a bitterness sensation enhancer that can enhance the bitterness sensation of bitter foods and beverages by this bitterness sensation and is versatile.

[0006] In view of the above, an object of the present invention is to provide a novel bitterness enhancer, a flavor-imparting composition for enhancing bitterness containing the bitterness enhancer, and a method for enhancing the bitterness of foods and beverages. [Means for solving the problem]

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the inventors have discovered that a pyrrole analogue, which is a compound represented by the following formula (1), has an excellent effect of enhancing the bitterness sensation in bitter foods and beverages, and have thus completed the invention of the present application.

[0008] Thus, the present invention provides the following: (1)The following formula (1):

[0009] [ka]

[0010] A bitterness sensation enhancer comprising, as an active ingredient, a compound represented by the above formula (1), wherein R1 is a linear or branched alkyl group having 1 to 3 carbon atoms or a hydroxyl group, and R2 is a 1-pyrrolyl group, a 2-pyrrolyl group or a 3-pyrrolyl group. (2) The bitterness enhancer according to (1), which is a natural extract. (3) The bitterness sensation enhancer according to (2), wherein the raw material of the natural extract is at least one selected from the group consisting of green tea, oolong tea, black tea and cereal tea. (4) A method for enhancing the bitterness sensation of a food or drink, comprising the step of adding the bitterness sensation enhancer according to any one of (1) to (3) to the food or drink. (5) A flavor-imparting composition for enhancing bitterness sensation, comprising the bitterness sensation enhancer according to any one of (1) to (3). (6) A method for enhancing the bitterness sensation of a food or beverage, comprising the step of adding the flavor-imparting composition for enhancing the bitterness sensation described in (5) to the food or beverage. Effect of the Invention

[0011] According to the present invention, it is possible to provide a novel bitterness enhancer, a flavor-imparting composition for enhancing bitterness containing the bitterness enhancer, and a method for enhancing the bitterness of foods and beverages.

[0012] An embodiment of the present invention will be described in detail below. In this specification, "to" means a range including a lower limit and an upper limit, and "concentration (ppm, ppb, ppt)" and "%" respectively mean "mass concentration" and "mass percent concentration" unless otherwise specified. In addition, in this specification, "flavor" means one or more senses that can be changed by aroma (fragrance), typically including the sense of smell and / or taste.

[0013] In this specification, the term "bitter taste" includes not only bitter taste but also astringent taste or astringent taste, or a flavor that is a combination of these.

[0014] As used herein, the term "enhanced bitterness sensation" means that when the bitterness sensation enhancer of the present invention is added to a food or beverage that originally has a bitter taste, the sensation corresponding to the bitterness is enhanced by the flavor.

[0015] In this specification, the flavor of a food or drink may be referred to as “flavor.” In this specification, “adding” includes at least one of simply adding to an object by spraying, dropping, or the like, and mixing with an object.

[0016] (bitterness enhancer) The bitterness enhancer according to one embodiment of the present invention (hereinafter, sometimes referred to as the present bitterness enhancer) has the following formula (1):

[0017] [ka]

[0018] The active ingredient is a compound (hereinafter sometimes referred to as the present compound) represented by the above formula (1): [in which R1 is a linear or branched alkyl group having 1 to 3 carbon atoms or a hydroxyl group, and R2 is a 1-pyrrolyl group, a 2-pyrrolyl group, or a 3-pyrrolyl group].

[0019] According to JP 2019-26565 A, the compound in question is described as a compound that contributes to a fragrant roasted feeling, but it has never been known as a compound that can be used as a bitterness enhancer.

[0020] In this regard, the present inventors have conducted intensive research and found that the present compound is an active ingredient of a bitterness enhancer for food and beverages.The present bitterness enhancer containing a predetermined amount of the present compound can enhance the bitterness of a food or beverage by adding the bitterness enhancer to the food or beverage, as shown in the examples below.

[0021] (The Compound in Question) The compounds of the present invention may be synthetic or naturally derived and may be obtained by any method available to those skilled in the art. The compounds of the present invention obtained may be further purified, if necessary, by means of column chromatography or reduced pressure distillation.

[0022] In the above formula (1), R1 is a linear or branched alkyl group having 1 to 3 carbon atoms or a hydroxyl group (also referred to as an -OH group or a hydroxyl group). Specific examples of the linear or branched alkyl group having 1 to 3 carbon atoms as R1 include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

[0023] Among these, alkyl groups having a small number of carbon atoms and hydroxyl groups are preferred. Specifically, R1 is preferably a methyl group, an ethyl group, or a hydroxyl group, more preferably a methyl group or a hydroxyl group, and particularly preferably a methyl group.

[0024] In the above formula (1), R2 is a 1-pyrrolyl group (formula (a) below), a 2-pyrrolyl group (formula (b) below), or a 3-pyrrolyl group (formula (c) below) (note that in the following formulas (a) to (c), "*" indicates a binding site):

[0025] [ka] Among these, from the viewpoint of simplifying the production process and obtaining a compound with a higher bitterness enhancement effect (a small amount of the compound can exhibit the bitterness enhancement effect), R2 is preferably a 1-pyrrolyl group (above formula (a)) or a 2-pyrrolyl group (above formula (b)), and is particularly preferably a 1-pyrrolyl group (above formula (a)). When R2 is a 1-pyrrolyl group, the polarity of the compound is relatively lower than when it is a 2-pyrrolyl group or a 3-pyrrolyl group, and the melting point and boiling point are lower, which is thought to further enhance the bitterness enhancement effect.

[0026] Furthermore, in the above formula (1), the substitution position of "-CH2-R2" on the pyrrole ring may be the 2-position (the following formula (1-1)) or the 3-position (the following formula (1-2)). That is, the compound represented by the above formula (1) may take the following form:

[0027] [ka] In particular, from the viewpoint of obtaining a compound having a high bitterness sensation enhancing effect, the substitution position of "-CH2-R2" on the pyrrole ring is preferably the 2-position (the above formula (1-1)).

[0028] Preferred examples of the compound represented by the above formula (1) include the following compounds (A) to (E). Among them, compounds (A) and (B) are preferred from the viewpoint of their high bitterness sensation enhancing effect.

[0029] [ka]

[0030] The synthesis of the compound of the present invention can be carried out, for example, by appropriately modifying known methods or combining them, and can be carried out according to the method described in JP 2019-26565 A. That is, the compound of the present invention can be synthesized by simultaneously carrying out the Appel reaction and the addition reaction using 1-alkylpyrrole and 1-hydroxymethylpyrrole. In addition, a method of halogenating the hydroxyl group of 1-hydroxymethylpyrrole by a known method to obtain a halide, and then carrying out a coupling reaction between the halide and 1-alkylpyrrole may be used. Furthermore, a method of carrying out a coupling reaction between 1-alkyl-2-hydroxymethylpyrrole and pyrrole may be used.

[0031] (Natural extract) In addition, the method for producing the compound of the present invention is not particularly limited, and may be extracted from natural raw materials (e.g., green tea, black tea, oolong tea, barley tea, etc.). The method for extracting from natural raw materials is also not particularly limited, and may be performed, for example, according to the method described in JP-A-2019-156993.

[0032] More specifically, for example, a process for obtaining a distillate by steam distillation of a natural raw material. an adsorption step of contacting the distillate with an adsorbent; a washing step of passing an aqueous alcohol solution having a concentration of more than 0% by volume and less than 95% by volume through the adsorbent after the adsorption step; A composition containing the compound of the present invention at a high concentration can be prepared by a method for producing a purified natural extract, which method includes an elution step of eluting the components adsorbed to the adsorbent with an aqueous alcohol solution having a concentration of 95% by volume or more after the washing step.

[0033] (natural raw materials) The natural raw materials used for the production of the natural extract are not particularly limited, and examples thereof include processed products of tea, an evergreen tree of the Theaceae family, grain tea, herb tea, etc. Examples of processed products of tea (scientific name: Camellia sinensis (L) O. Kuntze), an evergreen tree of the Theaceae family, include raw leaves obtained from tea buds, leaves, stems, etc., and processed non-fermented tea, semi-fermented tea, and fermented tea. Examples of non-fermented tea include green tea (sencha, gyokuro, kabusecha, bancha, tamaryokucha, matcha, roasted tea, tencha, etc.); semi-fermented tea includes oolong tea, bagzhong tea, etc.; and fermented tea includes black tea, pu-erh tea, etc.

[0034] Examples of grain teas include barley tea (roasted barley), roasted malt, Job's tears tea (roasted Job's tears), roasted brown rice, buckwheat tea (roasted buckwheat), roasted corn, roasted sesame seeds, roasted quinoa, roasted amaranth, roasted millet, roasted barnyard millet, roasted foxtail millet, and roasted soybeans.

[0035] Examples of herbal teas include Habu tea, Gynostemma tea, Plantain tea, Cherry blossom tea, Amacha tea, Persimmon leaf tea, Kombu tea, Pine needle tea, Angelica leaf tea, Guava tea, Loquat leaf tea, Aloe tea, Turmeric tea, Horsetail tea, Safflower tea, Saffron tea, Comfrey tea, Wolfberry tea, Artemisia tea, Ginkgo leaf tea, Quince tea, Mulberry leaf tea, Burdock tea, Aralia tea, Dandelion tea, Sword bean tea, Elderberry tea, Licorice tea, Megusuri tea, and Monk fruit tea.

[0036] In particular, in order to obtain an extract having a high content of the present compound, it is preferable that the natural raw material contains at least one selected from the group consisting of green tea, oolong tea, black tea, and grain tea, and it is particularly preferable to obtain an extract using roasted tea. Here, "roasted tea" means tea that has been heated and dried without using oil or water as a heat medium. In order to obtain an extract having a high content of the present compound, it is particularly preferable to obtain an extract using roasted tea.

[0037] (Steam distillation process) Steam distillation can be carried out by using a known method or by appropriately modifying it. For example, steam is blown into the bottom of a steam still containing the natural raw materials, or the water in the steam still is boiled and the distillate steam is cooled by a cooler connected to the distillation side at the top. By such an operation, a distillate containing aroma components can be collected as a condensate.

[0038] When performing steam distillation, any of pressurized steam distillation, atmospheric pressure steam distillation and reduced pressure steam distillation may be used. From the viewpoint of reducing loss of aroma components, however, it is preferable to perform steam distillation at atmospheric pressure.

[0039] In the steam distillation, the temperature of the steam, the flow rate (supply amount) of the steam, the distillation time, the condensation (cooling) temperature, the amount of the effluent, etc. can be set arbitrarily according to the type of the natural raw material used for extraction. As an example, the temperature of the steam can be 80 to 130°C, the condensation (cooling) temperature can be 0 to 50°C, and the amount of the distillate can be 0.1 to 5 times the total weight of the natural raw material, but the ranges are not limited thereto.

[0040] Alternatively, a gas-liquid countercurrent contact distillation method may be used as an improved version of the steam distillation method. Specifically, a slurry of the natural raw material (a suspension of the natural raw material and water) that has been previously prepared is placed in the upper part of the column.

[0041] The slurry then enters the rotating cone, where the centrifugal force produced by the rotation of the cone causes the slurry to form a thin liquid layer, which then falls onto the fixed cone and moves to the next rotating cone. The slurry repeats this process to move to the bottom of the column, while steam is injected from the bottom of the column, which moves the steam to the top of the column while collecting aroma components, and the steam flowing out from the top of the column can be cooled to obtain a distillate.

[0042] An example of an apparatus capable of carrying out the above method is a spinning cone column (SCC) manufactured by Flavourtech, Inc. There are no particular limitations on the operating conditions of the apparatus, and those skilled in the art can set them appropriately.

[0043] (Adsorption process) In the adsorption step, the distillate is brought into contact with an adsorbent, whereby aroma components contained in the distillate are adsorbed onto the adsorbent.

[0044] The distillate can be used as it is, or after adjusting to an arbitrary concentration with water or the like. Note that, before contacting the distillate with the adsorbent, pretreatment such as concentration, filtration, decantation, centrifugation, salting out, etc. can be performed. By performing such pretreatment, the aroma components can be efficiently adsorbed to the adsorbent. The method of these pretreatments is not particularly limited, and can be performed using known means or by appropriately modifying them.

[0045] The distillate obtained by the above-mentioned step can be contacted with an adsorbent by a known method, for example, a method of passing the distillate through a column packed with an adsorbent, a method of dispersing the adsorbent in the distillate and stirring the mixture, and then separating the adsorbent by means of filtration, etc. From the viewpoint of work efficiency, the former method is preferably used.

[0046] When using a column, the flow rate of the distillate is not particularly limited. However, from the viewpoint of sufficiently adsorbing the aroma components, the space velocity (SV) is preferably 1 to 500 h -1 It is preferable that the temperature is 5 to 200 h. -1 It is more preferable that the temperature is within a range of 10 to 100 hours. -1 It is particularly preferable that the volume of the distillate is 100 to 5000 times, and more preferably 500 to 2000 times, in terms of volume. The space velocity (SV) is a unit that indicates how many times the volume of the adsorbent the liquid is passed through per hour. In this case, the pressure inside the column may be normal or pressurized. The amount of the distillate to be contacted with the adsorbent is not particularly limited, but from the viewpoint of reducing loss of aroma components, it is preferably 100 to 5000 times (volume) the volume of the adsorbent, and more preferably 500 to 2000 times (volume).

[0047] The adsorbent used in this step is not particularly limited, and for example, a synthetic adsorbent or silica gel can be used. It is preferable to use a synthetic adsorbent as the adsorbent from the viewpoints of excellent durability and obtaining a natural extract containing the present compound at a high concentration and high purity.

[0048] There are no particular limitations on the synthetic adsorbent that can be used, but it is preferable to use a synthetic adsorbent based on an organic resin, since it has excellent affinity with the target compound of the present invention and can improve the recovery rate.

[0049] Examples of such synthetic adsorbents include synthetic adsorbents based on aromatic resins, synthetic adsorbents based on methacrylic acid ester resins, and synthetic adsorbents based on acrylonitrile aliphatic resins. Among them, synthetic adsorbents based on aromatic resins are preferred because they have excellent affinity with the target compound and can improve the recovery rate. Examples of synthetic adsorbents based on aromatic resins include synthetic adsorbents based on styrene-divinylbenzene copolymers, synthetic adsorbents based on modified styrene-divinylbenzene copolymers, synthetic adsorbents based on ethylvinylbenzene-divinylbenzene copolymers, and synthetic adsorbents based on modified ethylvinylbenzene-divinylbenzene copolymers.

[0050] As the synthetic adsorbent, commercially available products can be used, and examples thereof include Diaion (registered trademark) HP20, HP21; Sepabeads (registered trademark) SP825L, SP850, SP700, SP70, SP207 (aromatic resins, manufactured by Mitsubishi Chemical Corporation); Amberlite (registered trademark) XAD-2, XAD-4, XAD-2000 (aromatic resins, manufactured by Organo Corporation); Diaion (registered trademark) HP1MG, HP2MG (methacrylic acid ester resins, manufactured by Mitsubishi Chemical Corporation).

[0051] Among these, it is preferable to use Sepabeads (registered trademark) SP207, which is a synthetic adsorbent based on a modified styrene-divinylbenzene copolymer in which bromine atoms are bonded to an aromatic resin, from the viewpoint of particularly excellent affinity with the target compound of the present invention.

[0052] The above adsorbents may be used alone or in combination of two or more kinds.

[0053] The adsorbent may be washed with water or a mixed solvent of water and an organic solvent before contacting the distillate. The organic solvent is preferably one that is miscible with water, and examples thereof include monoalcohols such as methanol, ethanol, n-propanol, and isopropanol; ketones such as acetone; and polyhydric alcohols such as ethylene glycol. The above organic solvents may be used alone or in combination of two or more.

[0054] (Cleaning process) The washing step is carried out after the adsorption step. In the washing step, an aqueous alcohol solution having a concentration of more than 0% by volume and less than 95% by volume (also referred to simply as a "low-concentration aqueous alcohol solution" in this specification) is passed through the adsorbent to which the aroma components are adsorbed. By carrying out such a washing step before the elution step, it is possible to effectively remove impurities contained in the distillate, and to improve the purity of the present compound in the obtained natural extract.

[0055] If washing is performed with water only in the washing step (i.e., if the alcohol concentration in the aqueous alcohol solution used is 0% by volume) or if the washing step is not performed at all, contaminants cannot be sufficiently removed, and the purity of the present compound in the obtained natural extract will decrease, which is undesirable.

[0056] On the other hand, if the alcohol concentration in the aqueous alcohol solution used in this step is 95% by volume or more, the compound of the present invention adsorbed to the adsorbent will be eluted, making it difficult to obtain the compound of the present invention at a high concentration.

[0057] In the washing step, before passing an aqueous alcohol solution having an alcohol concentration of more than 0% by volume and less than 95% by volume, washing may be performed by passing only water (pre-washing). The speed of passing the liquid (water) is not particularly limited, but from the viewpoint of sufficiently adsorbing the aroma components, it is preferable that the space velocity (SV) is 1 to 100 h -1 It is preferable that the temperature is within a range of 10 to 80 hours. -1 It is more preferable that the temperature is 30 to 60 hours. -1 It is particularly preferable that the amount of water is 0.5 to 100 times (volume) the amount of water to be passed through the adsorbent in the pre-washing step, and more preferably 1 to 50 times (volume) the amount of water to be passed through the adsorbent, from the viewpoint of sufficiently removing impurities and reducing loss of aroma components.

[0058] From the viewpoint of obtaining a natural extract having a high concentration of the present compound, the alcohol concentration in the low-concentration alcohol aqueous solution used in the washing step is preferably 5 to 90% by volume, more preferably 10 to 75% by volume. When the alcohol concentration is 90% by volume or less, or even 75% by volume or less, the elution rate of the target compound of the present invention becomes lower. On the other hand, when the alcohol concentration is 5% by volume or more, or 10% by volume or more, the elution of impurities is further promoted, and a natural extract having a high concentration of the present compound can be provided.

[0059] In this step, the concentration of the low-concentration aqueous alcohol solution passed through may be constant or may be varied. In order to concentrate the present compound with a higher purity, it is preferable to pass a plurality of low-concentration aqueous alcohol solutions with different alcohol concentrations through this step so that the alcohol concentration increases stepwise.

[0060] In this case, it is preferable that the low-concentration aqueous alcohol solution used has an alcohol concentration that is gradually increased by changing the alcohol concentration within a range of 10 to 30% by volume.

[0061] The method of passing the low-concentration alcohol aqueous solution through the adsorbent to which the aroma components have been adsorbed can be a known method, for example, a method of passing the low-concentration alcohol aqueous solution through a column packed with an adsorbent (the adsorbent to which the aroma components have been adsorbed in the above-mentioned adsorption process). The flow rate at this time is not particularly limited, but from the viewpoint of sufficiently removing impurities, it is preferable that the space velocity (SV) is 1 to 100 h -1 It is preferable that the temperature is 1.5 to 50 h. -1 It is more preferable that the temperature is within a range of 2 to 30 hours. -1 It is particularly preferable that the amount of the low-concentration aqueous alcohol solution is 0.5 to 100 times (volume) the amount of the adsorbent, and more preferably 1 to 50 times (volume) the amount of the adsorbent, from the viewpoint of sufficiently removing impurities and reducing loss of aroma components.

[0062] The low-concentration aqueous alcohol solution is preferably passed through while measuring the contents of components contained in the effluent, and while confirming that the amount of the target compound of the present invention that is effluent is small.

[0063] As the alcohol contained in the low-concentration alcoholic aqueous solution, a lower alcohol is preferred from the viewpoints of easy miscibility with water and easy elution of impurities, and methanol, ethanol, n-propanol, isopropanol, etc. can be used. Among them, ethanol or n-propanol is preferred from the viewpoints of easy control of the elution of the target compound of the present invention and safety of the obtained natural extract in food and beverage applications, and ethanol is particularly preferred. The alcohol contained in the low-concentration alcoholic aqueous solution may be used alone or in a mixture of two or more kinds.

[0064] The water contained in the low-concentration aqueous alcohol solution is not particularly limited, and tap water, distilled water, pure water, ion-exchanged water, etc. can be used.

[0065] (Elution process) The elution step is carried out after the above-mentioned washing step. In the elution step, the components (aroma components) adsorbed to the adsorbent are eluted with an alcohol aqueous solution having a concentration of 95% by volume or more (also referred to simply as "high-concentration alcohol aqueous solution" in this specification). By carrying out such an elution step, a natural extract containing the present compound at a high concentration can be obtained.

[0066] In the elution step, if the elution is performed with an alcoholic aqueous solution of less than 95% by volume, the concentration of the target compound of the present invention in the obtained natural extract will decrease, and the amount of the alcoholic aqueous solution required to recover the target compound of the present invention adsorbed on the adsorbent will increase, which is unfavorable from the viewpoint of work efficiency.

[0067] In order to obtain a natural extract containing the target compound of the present invention at a higher concentration and with a higher purity, the alcohol concentration in the high-concentration aqueous alcohol solution used in the elution step is preferably 95 to 100% by volume, and more preferably 95 to 99% by volume.

[0068] The method of eluting the aroma components adsorbed to the adsorbent using a high-concentration aqueous alcohol solution can be a known method, for example, a method of passing a high-concentration aqueous alcohol solution through an adsorbent packed in a column, a method of dispersing the adsorbent in a high-concentration aqueous alcohol solution, stirring the mixture, and then separating the adsorbent by means of filtration or the like, etc. From the viewpoint of work efficiency, the former method is preferably used.

[0069] When using a column, there is no particular restriction on the flow rate of the high-concentration alcohol aqueous solution. However, from the viewpoint of sufficiently eluting the aroma components, it is recommended that the spatial velocity (SV) is 0.1 to 10 h -1In this case, the pressure inside the column may be normal pressure or pressurized. The amount of the high-concentration aqueous alcohol solution passed through is not particularly limited, but from the viewpoint of suppressing the aroma components from remaining in the adsorbent, it is preferably 0.1 to 100 times (volume) the amount of the adsorbent, and more preferably 0.5 to 30 times (volume). When the amount of the high-concentration aqueous alcohol solution passed through is 100 times or less, or even 30 times or less, a natural extract in which the target compound of the present invention is highly concentrated can be obtained.

[0070] As the alcohol contained in the high-concentration alcoholic aqueous solution, a lower alcohol is preferable because it is easily miscible with water and easily dissolves the target compound of the present invention, and methanol, ethanol, n-propanol, isopropanol, etc. can be used. Among them, ethanol or n-propanol is preferable, and ethanol is particularly preferable, in terms of facilitating the dissolution of the target compound of the present invention and the safety of the obtained natural product in food and beverage applications. The alcohol contained in the high-concentration alcoholic aqueous solution may be used alone or in a mixture of two or more kinds.

[0071] The water contained in the high-concentration alcohol aqueous solution is not particularly limited, and tap water, distilled water, pure water, ion-exchanged water, etc. can be used. Furthermore, the high-concentration alcohol aqueous solution used in the present invention may be mixed with an organic solvent other than alcohol as appropriate. The organic solvent is not particularly limited, but examples thereof include hydrocarbons such as pentane, hexane, heptane, and cyclohexane, ketones such as acetone, esters such as ethyl acetate, and ethers such as diethyl ether.

[0072] The eluate obtained by the elution step can be used as it is as the bitterness sensation enhancer of the present invention, or the eluate can be further concentrated to remove the solvent, or the concentration and / or purity of the present compound can be increased by combining techniques such as distillation and various types of chromatography to obtain the bitterness sensation enhancer of the present invention.

[0073] The bitterness sensation enhancer of the present invention, which is a natural extract, preferably contains the compound of the present invention at a concentration of 5.5 ppm or more, more preferably 6 ppm or more, and even more preferably 10 ppm or more. The concentration of the compound of the present invention contained in the natural extract of the present invention is measured by the method described in the Examples (the method described in the section "Analysis of tea extract").

[0074] (bitterness enhancer) The bitterness enhancer of the present invention may be composed of only the present compound, or may contain other components such as a solvent as long as it contains a predetermined amount of the present compound. The concentration of the present compound in the bitterness enhancer of the present invention can be determined arbitrarily depending on the object to which the bitterness enhancer is added. Examples of the concentration of the present compound include a range of 0.1 ppb to 100%, preferably 0.5 ppb to 10%, and more preferably 2 ppb to 1% based on the total mass of the bitterness enhancer. More specifically, the lower limit is set to any one of 0.1 ppb, 0.2 ppb, 0.5 ppb, 1 ppb, 2 ppb, 5 ppb, 10 ppb, 20 ppb, 50 ppb, 100 ppb, 200 ppb, 500 ppb, 1 ppm, 2 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, 100 ppm, 0.1%, 0.2%, 0.5%, 1%, 2%, 5%, 10%, 20%, and 50%, and the upper limit is set to 100%, 50%, 20%, 10 %, 5%, 2%, 1%, 0.5%, 0.2%, 0.1%, 500 ppm, 200 ppm, 100 ppm, 50 ppm, 20 ppm, 10 ppm, 5 ppm, 2 ppm1 ppm, 500 ppb, 200 ppb, 100 ppb, 50 ppb, 20 ppb, 10 ppb, 5 ppb, 2 ppb, or 1 ppb, and the range can be any combination of these lower and upper limits, but is not limited to these.

[0075] The bitterness enhancer of the present invention can be added to a flavor composition (including a flavor composition) or to food or drink. The details of each of the additives will be described later.

[0076] (Flavor-imparting composition for enhancing bitterness sensation) The bitterness sensation enhancing composition of the present invention may be added to food or beverages by itself, or may be added to food or beverages together with one or more selected from one or more water-soluble or oil-soluble flavors, emulsified flavor compositions, any flavor compounds, and natural essential oils (for example, the flavor compounds described in the above-mentioned "Japan Patent Office Gazette, Collection of Well-Known and Commonly Used Technology (Flavors) Part II Food Flavors," "Survey on the Actual Use of Food Flavor Compounds in Japan," and "Synthetic Flavors: Chemistry and Product Knowledge") (hereinafter referred to as the "flavor-imparting composition")

[0077] A flavor-imparting composition for enhancing bitterness sensation according to one embodiment of the present invention is obtained by adding the present bitterness enhancer to a flavor-imparting composition. By adding an effective amount of the present bitterness enhancer to a flavor-imparting composition, a bitterness sensation enhancing effect can be imparted to the flavor-imparting composition to which it is added. Here, the "bitterness sensation enhancing effect" means "the effect of the flavor-imparting composition to which the present bitterness enhancer has been added, enhancing the bitterness sensation of the food, beverage, or other product to which it is added."

[0078] In the composition, the amount of the present bitterness enhancer added to the flavor imparting composition to which it is added may be an effective amount that imparts the bitterness enhancement effect by the present compound contained as an active ingredient, and may be arbitrarily set according to the type and form of the flavor imparting composition to which it is added. Specific examples of the concentration of the present compound in the flavor imparting composition for enhancing bitterness include the same concentration ranges as those explained in the above section on "the present compound."

[0079] (Flavoring composition) The flavor imparting composition to which the present bitterness sensation enhancer is added will be described below. The flavor imparting composition exerts an excellent flavor imparting effect when added to various articles. The article to which the flavor imparting composition is added is not particularly limited, and examples thereof include other flavor imparting compositions and food and drink. Examples of the flavor imparting composition include a flavor composition, a flavor improving agent, a flavor modulating agent, a flavor imparting agent, a flavor improving agent, a flavor modulating agent, a taste imparting agent, a taste improving agent, and a taste modulating agent.

[0080] The present bitterness sensation enhancer can be added to a flavor-imparting composition to impart a bitterness sensation effect. That is, the flavor-imparting composition to which the present bitterness sensation enhancer has been added can be used as a flavor-imparting composition for enhancing bitterness sensation.

[0081] In addition, by constituting the present bitterness sensation enhancer with the present compound and a compound capable of imparting flavor (e.g., a flavor compound), the present bitterness sensation enhancer can also be used as a flavor imparting composition for enhancing bitterness sensation.

[0082] A specific example of the flavor composition, which is one embodiment of the flavor-imparting composition, is a flavor composition for food and beverages (also referred to as a flavor composition). Examples of the articles to which the flavor-imparting composition is added include foods and beverages, as described above.

[0083] The flavoring composition may contain the following compounds or ingredients. Examples of such compounds or ingredients include various kinds of flavor compounds or flavor compositions, oil-soluble dyes, vitamins, functional substances, fish meat extracts, livestock meat extracts, plant extracts, yeast extracts, animal and plant proteins, animal and plant protein hydrolysates, starch, dextrin, sugars, amino acids, nucleic acids, organic acids, and solvents. Examples of such compounds include natural essential oils, natural flavors, and synthetic flavors described in "Japan Patent Office Gazette, Collection of Well-Known and Commonly Used Technologies (Flavors) Part II Food Flavors, published January 14, 2000," "Survey on the Actual Use of Food Flavor Compounds in Japan" (Report on the Ministry of Health, Labor, and Welfare's Research in 2000, Japan Flavor and Flavor Manufacturers Association, published March 2001), and "Synthetic Flavor Chemistry and Product Knowledge" (revised and updated December 20, 2016, edited by the Synthetic Flavor Editorial Committee, Chemical Daily Co., Ltd.).

[0084] Specific examples of synthetic fragrance compounds include hydrocarbon compounds such as monoterpenes such as α-pinene, β-pinene, γ-terpinene, myrcene, camphene, and limonene, sesquiterpenes such as valencene, cedrene, caryophyllene, and longifolene, and 1,3,5-undecatriene.

[0085] Examples of the alcohol compound include saturated alcohols such as butanol, pentanol, 3-octanol, and hexanol; unsaturated alcohols such as (Z)-3-hexen-1-ol, prenol, and 2,6-nonadienol; terpene alcohols such as linalool, geraniol, citronellol, tetrahydromyrcenol, farnesol, nerolidol, cedrol, α-terpineol, terpinen-4-ol, and borneol; and aromatic alcohols such as benzyl alcohol, phenylethyl alcohol, and cinnamyl alcohol.

[0086] Examples of the aldehyde compound include saturated aldehydes such as acetaldehyde, hexanal, octanal, and decanal; unsaturated aldehydes such as (E)-2-hexenal and 2,4-octadienal; terpene aldehydes such as citronellal, hydroxycitronellal, citral, myrtenal, and perillaldehyde; and aromatic aldehydes such as benzaldehyde, cinnamyl aldehyde, vanillin, ethyl vanillin, heliotropin, and p-tolyl aldehyde.

[0087] Examples of ketone compounds include saturated and unsaturated ketones such as 2-heptanone, 2-undecanone, 1-octen-3-one, acetoin, and 6-methyl-5-hepten-2-one (methylheptenone); diketones and hydroxyketones such as diacetyl, 2,3-pentanedione, maltol, ethyl maltol, cyclotene, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone; terpene ketones such as carvone, menthone, and nootkatone; ketones derived from terpene degradation products such as α-ionone, β-ionone, and β-damascenone; and aromatic ketones such as raspberry ketone.

[0088] Examples of the furan or ether compounds include furfuryl alcohol, furfural, rose oxide, linalool oxide, menthofuran, theaspirane, estragole, eugenol, and 1,8-cineole.

[0089] Examples of the ester compound include aliphatic esters such as ethyl acetate, isoamyl acetate, octyl acetate, ethyl butyrate, ethyl isobutyrate, isoamyl butyrate, ethyl 2-methylbutyrate, ethyl isovalerate, 2-methylbutyl isobutyrate, ethyl hexanoate, allyl hexanoate, ethyl heptanoate, ethyl octanoate, isoamyl isovalerate, and ethyl nonanoate; terpene alcohol esters such as linalyl acetate, geranyl acetate, lavandulyl acetate, terpinyl acetate, and neryl acetate; and aromatic esters such as benzyl acetate, methyl salicylate, methyl cinnamate, cinnamyl propionate, ethyl benzoate, cinnamyl isovalerate, and ethyl 3-methyl-2-phenylglycidate.

[0090] Examples of the lactone compound include saturated lactones such as γ-decalactone, γ-dodecalactone, δ-decalactone, and δ-dodecalactone, and unsaturated lactones such as 7-decen-4-olide and 2-decen-5-olide.

[0091] Examples of acid compounds include saturated and unsaturated fatty acids such as acetic acid, butyric acid, isovaleric acid, hexanoic acid, octanoic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.

[0092] Examples of the nitrogen-containing compound include indole, skatole, pyridine, alkyl-substituted pyrazine, methyl anthranilate, and trimethylpyrazine.

[0093] Examples of sulfur-containing compounds include methanethiol, dimethyl sulfide, dimethyl disulfide, allyl isothiocyanate, 3-methyl-2-butene-1-thiol, 3-methyl-2-butanethiol, 3-methyl-1-butanethiol, 2-methyl-1-butanethiol, 3-mercaptohexanol, 4-mercapto-4-methyl-2-pentanone, 3-mercaptohexyl acetate, p-mentha-8-thiol-3-one, and furfuryl mercaptan.

[0094] Natural essential oils include sweet orange, bitter orange, petitgrain, lemon, bergamot, mandarin, neroli, peppermint, spearmint, lavender, chamomile, rosemary, eucalyptus, sage, basil, rose, hyacinth, lilac, geranium, jasmine, ylang-ylang, anise, clove, ginger, nutmeg, cardamom, cedar, cypress, vetiver, patchouli, and labdanum.

[0095] Examples of various animal and plant extracts include herb or spice extracts, or extracts of coffee, green tea, black tea, or oolong tea, milk or dairy products, and various enzymatic decomposition products thereof using lipase or protease, etc.

[0096] The form of the flavor composition is not particularly limited, and examples thereof include a water-soluble flavor composition, an oil-soluble flavor composition, an emulsion flavor composition, and a powder flavor composition. Preferred examples of the form of the flavor composition include a solution in which the present bitterness enhancer or other components are dissolved in a water-soluble or oil-soluble solvent, an emulsion preparation, a powder preparation, or other solid preparations (such as solid fats).

[0097] Examples of the water-soluble solvent include ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, isopropanol, methyl ethyl ketone, glycerin, propylene glycol, dipropylene glycol, etc. Among these, from the viewpoint of use in food and beverages, ethanol, glycerin, or propylene glycol is particularly preferred.

[0098] Examples of oil-soluble solvents include vegetable oils and fats, animal oils and fats, refined oils and fats (for example, processed oils and fats such as medium-chain fatty acid triglycerides, and short-chain fatty acid triglycerides such as triacetin and tripropionin), various essential oils, and triethyl citrate.

[0099] In addition, to prepare an emulsion preparation, the present flavoring composition can be emulsified with a water-soluble solvent and an emulsifier. The method of emulsifying the present flavoring composition is not particularly limited, and an emulsion with excellent stability can be obtained by emulsifying the composition with various types of emulsifiers conventionally used in foods and beverages, such as fatty acid monoglycerides, fatty acid diglycerides, fatty acid triglycerides, propylene glycol fatty acid esters, sucrose fatty acid esters, polyglycerin fatty acid esters, lecithin, processed starch, sorbitan fatty acid esters, Quillaja extract, gum arabic, tragacanth gum, guar gum, karaya gum, xanthan gum, pectin, alginic acid and its salts, carrageenan, gelatin, Quillaja casein saponin, or sodium caseinate, using a homomixer, colloid mill, rotating disk homogenizer, high pressure homogenizer, etc. The amount of these emulsifiers used is not strictly limited and can be changed over a wide range depending on the type of emulsifier used, but is usually within the range of about 0.01 to about 100 parts by mass, preferably about 0.1 to about 50 parts by mass, per 1 part by mass of the compound of the present invention. In addition, in order to stabilize the emulsified state, one or a mixture of two or more polyhydric alcohols such as glycerin, propylene glycol, sorbitol, maltitol, sucrose, glucose, trehalose, sugar solution, and reduced starch syrup can be added to the emulsion in addition to water.

[0100] The emulsion thus obtained can be dried to produce a powder formulation, if desired. When producing the powder, sugars such as gum arabic, trehalose, dextrin, sugar, lactose, glucose, starch syrup, and reduced starch syrup can be added as needed. The amount of these to be used can be appropriately selected depending on the desired properties of the powder formulation.

[0101] In addition to the above, the present fragrance composition may contain, if necessary, ingredients that are commonly used in fragrance compositions, such as solvents such as water and ethanol, and fragrance retainers such as ethylene glycol, propylene glycol, dipropylene glycol, glycerin, hexylene glycol, benzyl benzoate, triethyl citrate, diethyl phthalate, Hercolin, medium-chain fatty acid triglycerides, and medium-chain fatty acid diglycerides.

[0102] (Method for enhancing bitterness of food and beverages) A method for enhancing the bitterness sensation of food or beverage according to one embodiment of the present invention (hereinafter referred to as "the present bitterness sensation enhancing method") includes a step of adding the present bitterness sensation enhancer or a flavor-imparting composition for enhancing bitterness sensation to a food or beverage.

[0103] By adding an effective amount of the present bitterness enhancing composition or the flavor-imparting composition for enhancing bitterness to a food or drink having a bitter taste, the bitterness of the food or drink to which it is added can be enhanced.

[0104] In this method, the amount of the bitterness enhancer added to the food or beverage to which it is to be added need only be an effective amount that enhances the bitterness sensation due to the compound of the present invention contained as an active ingredient, and can be set arbitrarily depending on the type and form of the food or beverage to which it is to be added.

[0105] When the compound is added to a food or drink, the concentration of the compound of the present invention is preferably within a range of at least 0.01 ppt to 100 ppt based on the total mass of the food or drink to impart a bitter taste, and within a range of 0.05 ppt to 20 ppt to impart a bitter taste more satisfactorily. More specifically, the lower limit may be any of 0.01 ppt, 0.02 ppt, 0.05 ppt, 0.1 ppt, 0.2 ppt, 0.5 ppt, 1 ppt, 2 ppt, 5 ppt, 10 ppt, 20 ppt, and 50 ppt, and the upper limit may be any of 100 ppt, 50 ppt, 20 ppt, 10 ppt, 5 ppt, 2 ppt, 1 ppt, 0.5 ppt, 0.2 ppt, 0.1 ppt, 0.05 ppt, and 0.02 ppt, and the range may be any combination of the lower limit and upper limit, but is not limited thereto.

[0106] In this method, the method for adding the bitterness sensation enhancing composition of the present invention to food or drink is not particularly limited. Furthermore, there is no particular limitation on the time (timing) at which the bitterness sensation enhancing composition of the present invention is added to food or drink.

[0107] (Foods with a bitter taste) Foods and beverages that are the subject of the method for enhancing the bitterness sensation of foods and beverages according to one embodiment of the present invention are not particularly limited as long as they have a bitter taste, and examples of such foods and beverages include confectioneries such as rice crackers, arare, okoshi, mochi, manju, uirou, bean paste, yokan, mizuyokan, kingyoku, jelly, castella, candy, biscuits, crackers, potato chips, cookies, pies, puddings, butter cream, custard cream, cream puffs, waffles, sponge cakes, donuts, chocolate, chewing gum, caramel, candy, peanut paste or other pastes; breads, noodles, rice dishes, other grains, such as bread, udon, ramen, Chinese noodles, sushi, gomoku-han, fried rice, pilaf, gyoza wrappers, shumai wrappers, okonomiyaki, and takoyaki; and pickled plums, pickled plums, fukujin-zuke, bettara-zuke, senma-zuke, scallions, miso-zuke, and takuan-zuke, as well as the bases for these pickles. pickled vegetables; fish such as mackerel, sardines, pacific saury, salmon, tuna, bonito, whale, flounder, sand lance, sweetfish, etc.; squids such as pacific flying squid, spear squid, crested squid, firefly squid, etc.; octopus such as common octopus and Japanese octopus; shrimps such as kuruma shrimp, button shrimp, spiny lobster, black tiger shrimp, etc.; crabs such as king crab, snow crab, blue crab, hairy crab, etc.; shellfish such as clams, mussels, scallops, oysters, mussels, etc.; canned and boiled fish, Processed seafood foods and drinks such as tsukudani, surimi, fish paste products (chikuwa, kamaboko, fried kamaboko, crab leg kamaboko, etc.), fries, tempura, etc.; livestock meats such as chicken, pork, beef, lamb, horse meat, etc.; processed meats such as curry, stew, beef stew, hayashi rice sauce, meat sauce, mapo tofu, hamburger steak, dumplings, kamameshi base, soups (corn soup, tomato soup, consommé soup, etc.), meatballs, braised pork, canned meat, etc.;Table salt, seasoning salt, soy sauce, powdered soy sauce, miso, powdered miso, moromi, hisio, furikake, ochazuke seasoning, margarine, mayonnaise, dressing, vinegar, sanbaizu, powdered sushi vinegar, Chinese seasoning, tempura sauce, noodle sauce (kelp stock or bonito stock, etc.), sauce (medium-thick sauce, tomato sauce, etc.), ketchup, yakiniku sauce, curry roux, stew seasoning, soup seasoning, dashi seasoning (kelp stock or bonito stock, etc.), compound seasoning, new mirin, fried chicken powder, takoyaki powder, and other miso seasonings. seasonings such as malt powder, and animal or vegetable broth-flavored foods and beverages to which these seasonings have been added; dairy products such as cheese, yogurt, and butter; various yeasts such as brewer's yeast and baker's yeast, and various microbial fermentation products such as lactic acid bacteria; simmered vegetables, Chikuzenni, oden, hotpots, and other simmered dishes; take-out bento box ingredients and side dishes; fruit juice drinks and soft drinks containing fruit juice such as apples, grapes, and citrus fruits (grapefruit, oranges, lemons, etc.), fruit pulp drinks and fruit drinks containing fruit pieces Examples of such beverages include vegetables such as tomatoes, bell peppers, celery, melons, bitter melons, carrots, potatoes, asparagus, bracken, and osmanthus, as well as vegetable-based beverages and vegetable soups that contain these vegetables; coffee beverages, cocoa beverages, tea beverages such as green tea, black tea, and oolong tea, cola beverages, carbonated beverages (ciders with various flavors such as citrus flavors), and lactic acid bacteria beverages; beverages containing herbal medicines and herbs; functional beverages such as sports drinks, honey beverages, vitamin supplement beverages, mineral supplement beverages, nutritional drinks, nutritious drinks, and lactic acid bacteria beverages; non-alcoholic and alcoholic flavored beverages with an alcohol content of less than 1 vol.% that have a flavor of various types of alcohol (beer, plum wine, chuhai, etc.); beer-flavored beverages such as wine, shochu, awamori, sake, beer, chuhai, cocktail drinks, happoshu, fruit wine, condiment wine, and so-called "third beer", or alcoholic beverages that contain these;

[0108] Among these, foods and beverages containing bitter substances are particularly preferred. Examples of bitter substances include, but are not limited to, diketopiperazine, caffeine, isohumulones, reduced isohumulones, quassin, naringin, absinthin, absorbins, catechins, chlorogenic acids, momordicine, aloin, aloenin, barbaloin, quinine, wormwood extract, citrus extract, bitter persimmon extract, coffee extract, tea extract, bitter melon extract, lotus germ extract, aloe arborescens extract, rosemary extract, lychee extract, laurel extract, sage extract, caraway extract, and hop extract. EXAMPLES

[0109] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these.

[0110] (Reference example 1) The following compounds (A) to (D) were synthesized according to the methods described in Synthesis Example 1 and Composition Example 2 of JP 2019-26565 A. Compound (A): 1-ethyl-2-(1-pyrrolylmethyl)pyrrole Compound (B): 1-ethyl-3-(1-pyrrolylmethyl)pyrrole Compound (C): 1-ethyl-2-(2-pyrrolylmethyl)pyrrole Compound (D): 1-hydroxymethyl-2-(1-pyrrolylmethyl)pyrrole

[0111] (Reference Example 2) Addition to water Compound (A) was added to water to give the concentration shown in Table 1, and the bitterness of the resulting aqueous solution was evaluated by 20 expert panelists. The evaluation criteria were as follows: (Evaluation Criteria) -: No bitterness at all +: Slightly bitter taste ++: Bitterness is clearly noticeable +++: Strong bitterness is felt They also wrote down their evaluation of the flavor of the aqueous solution when they drank it. The average evaluation results are shown in Table 1.

[0112] [Table 1]

[0113] As shown in Table 1, when the concentration of compound (A) added to water was 10 ppt or less, neither bitterness nor any other flavor was felt. On the other hand, when the concentration of compound (A) added to water was 20 ppt or more, a roasted flavor was felt as a flavor evaluation other than bitterness, and this flavor became stronger with increasing concentration. However, when compound (A) was added alone, no bitterness was felt at any concentration.

[0114] (Example 1) Addition of the bitterness enhancer of the present invention (compound (A)) to an aqueous diketopiperazine solution Diketopiperazine is a substance produced by heating amino acids, and is present in a wide range of foods and beverages, and is known to contribute to the bitterness of foods and beverages. Therefore, the effect of the bitterness enhancer of the present invention on cycloprolylvaline, one of the representative diketopiperazines, was confirmed. A 500 ppm aqueous solution (about twice the bitterness threshold) of cycloprolylvaline (FUJIFILM Wako Pure Chemical Corporation) was prepared, and 1 ppt (less than the flavor threshold) of compound (A) was added to it, and the aqueous solution without compound (A) and the aqueous solution with 1 ppt of compound (A) were evaluated for bitterness by 20 expert panelists.

[0115] According to a report by Stark et al. (J. Agric. Food Chem. 2006, 54 (15), 5530-5539), the bitterness threshold of cycloprolylvaline is 1.28 mmol, which is calculated to be approximately 250 ppm based on the molecular weight of cycloprolylvaline (196.25).

[0116] The bitterness was evaluated by presenting both the sample with and without compound (A) without knowing the contents of the compound, and asking the subjects to evaluate which tasted more bitter. As a result, all 20 subjects rated the sample with 1 ppt of compound (A) as having the stronger bitterness.

[0117] (Example 2) Examination of Compound (A) Concentration In Example 1, the concentration of compound (A) added was changed to 0.1 ppt, and the other conditions were the same as in Example 1, and the sensory evaluation was carried out.

[0118] As a result, 17 out of 20 subjects rated the sample containing 0.1 ppt of compound (A) as having a strong bitter taste.

[0119] From Reference Example 2, Example 1 and Example 2, it was found that when compound (A) was added alone to water, the addition of 10 ppt did not impart any bitterness or other flavors, but when compound (A) was added to an aqueous solution of diketopiperazine (cycloprolylvaline), a bitter substance, the addition of 0.1 ppt of compound (A) enhanced the bitterness.

[0120] (Example 3) Addition of the bitterness enhancer of the present invention (compounds (B) to (D)) to a diketopiperazine aqueous solution Each of the compounds (B) to (D) was also evaluated in the same manner as in Example 1. As a result, all 20 panelists evaluated that the samples containing 1 ppt each of the compounds (B) to (D) had a stronger bitter taste than the samples without the compounds (B) to (D).

[0121] (Example 4) Enhancement of bitterness for cycloprolyl proline The effect of the bitterness sensation enhancer of the present invention on cycloprolylproline, which is a diketopiperazine different from those in Examples 1 to 3, was confirmed. A 1000 ppm aqueous solution (about twice the bitterness threshold) of cycloprolylproline (Peptide Institute, Inc.) was prepared, and 1 ppt (less than the flavor threshold) of compound (A) was added thereto. A panel of 20 experts evaluated the bitterness of the aqueous solution without compound (A) and the aqueous solution with 1 ppt of compound (A) added.

[0122] According to the report by Stark et al. (J. Agric. Food Chem. 2006, 54 (15), 5530-5539), the bitterness threshold of cycloprolylproline is 2.58 mmol, which is calculated to be approximately 500 ppm based on the molecular weight of cycloprolylproline (194.23).

[0123] The bitterness was evaluated by presenting both the sample with and without compound (A) without knowing the contents of the compound, and asking the subjects to evaluate which tasted more bitter. As a result, all 20 subjects rated the sample with 1 ppt of compound (A) as having the stronger bitterness.

[0124] (Example 5) Addition of the bitterness enhancer of the present invention to commercially available unsweetened black coffee Commercially available unsweetened black coffee was prepared and 1 ppt of compound (A) was added to it. The bitterness of the commercially available unsweetened black coffee without added compound (A) and the commercially available unsweetened black coffee with added 1 ppt of compound (A) was evaluated by 20 expert panelists.

[0125] The sensory evaluation method was carried out by drinking the commercially available unsweetened black coffee (without compound (A)) in advance, and discussing and discussing five items (top aroma, fragrant, metallic, strength (richness, full body), bitterness (including astringency)) and evaluating them with the commercially available unsweetened black coffee without additives as the standard, with a score of -1: slightly decreased, a score of 0: no change was felt, a score of 1: slightly increased, a score of 2: clearly increased, and a score of 3: significantly increased. The average scores are shown in Table 2.

[0126] [Table 2]

[0127] As shown in Table 2, when compound (A) was added at 1 ppt (below the flavor threshold in an aqueous solution) to commercially available unsweetened black coffee, the effect of enhancing the bitterness was observed, with almost no effect on the top aroma, fragrantness, metallicity, and richness (richness, body).

[0128] (Example 6) Preparation of coffee flavor for enhancing bitterness sensation containing compound (A) The components (parts by weight) in Table 3 below were mixed together to form a coffee-like blended flavor composition (Comparative Product 1).

[0129] [Table 3]

[0130] Compound (A) was added at 1 ppb to the comparative product 1 to prepare a bitterness enhancing coffee flavor of the present invention (product 1 of the present invention).

[0131] (Example 7) Addition of the present invention's coffee flavor for enhancing bitterness to unsweetened black coffee 50g of roasted coffee beans (Columbia L value 22) were ground, dripped with 90°C hot water to obtain 400g of extract, and cooled to around room temperature. The Bx of the obtained extract was 2.9°. 0.6g of sodium bicarbonate and 599.4g of water were added to make 1000g. This was divided into small portions to prepare 0.1% of Comparative Product 1 or 0.1% of the present invention product 1, which were heated to 90°C, filled into cans and retort sterilized (121°C, 10 minutes) to obtain canned unsweetened black coffee. Each unsweetened black coffee was evaluated by 20 panelists on bitterness (including astringency) based on the unsweetened black coffee to which Comparative Product 1 was added, with the following as the standard: -1 point: slightly decreased, 0 point: no change felt at all, 1 point: slightly increased, 2 points: clearly increased, 3 points: significantly increased. The average scores are shown in Table 4.

[0132] [Table 4]

[0133] As shown in Table 4, the bitterness of unsweetened black coffee containing the bitterness enhancing coffee flavor of the present invention was clearly enhanced compared to the bitterness of unsweetened black coffee containing the coffee flavor without the compound (A) of the present invention.

[0134] (Example 8) Addition of the bitterness enhancer of the present invention to a commercially available beer-flavored beverage A commercially available beer-flavored beverage (third beer) was prepared and 1 ppt of compound (A) was added to it. A panel of 20 expert panelists evaluated the bitterness of the commercially available beer-flavored beverage (third beer) without added compound (A) and the commercially available beer-flavored beverage (third beer) with added 1 ppt of compound (A).

[0135] The sensory evaluation method was as follows: participants first drank the commercially available beer-flavored beverage (third beer) (containing no compound (A)) and discussed and discussed six items (top aroma, floral flavor, malt flavor, richness, bitterness (including astringency)) were evaluated based on the additive-free commercially available beer-flavored beverage (third beer) as follows: -1 point: slightly decreased, 0 point: no change was felt, 1 point: slightly increased, 2 points: clearly increased, 3 points: significantly increased. The average scores are shown in Table 5.

[0136] [Table 5]

[0137] As shown in Table 5, when compound (A) was added at 1 ppt (below the flavor threshold in an aqueous solution) to a commercially available beer-flavored beverage (third beer), the effect of enhancing the bitterness and astringency was observed, with almost no effect on the top aroma, floral flavor, malty flavor, or richness.

[0138] (Example 9) Preparation of beer flavor for enhancing bitterness sensation containing compound (A) The components (parts by weight) in Table 6 below were mixed to form a beer-like blended flavor composition (Comparative Product 2).

[0139] [Table 6]

[0140] Compound (A) was added to the comparative product 2 at 1 ppb to prepare a beer flavor for enhancing bitterness sensation of the present invention (product 2 of the present invention).

[0141] (Example 10) Addition of the beer flavor for enhancing bitterness of the present invention to a beer-taste beverage A non-alcoholic beer-flavored beverage was prepared according to the formulation in Table 7 below.

[0142] [Table 7]

[0143] Twenty panelists rated each non-alcoholic beer-flavored beverage for bitterness (including astringency) based on the bitterness of a non-alcoholic beer-flavored beverage containing Comparative Product 2, with the following scale: -1 point: slightly decreased, 0 point: no change was detected, 1 point: slightly increased, 2 points: clearly increased, 3 points: significantly increased. The average scores are shown in Table 8.

[0144] [Table 8]

[0145] As shown in Table 8, the non-alcoholic beer-flavored beverage containing the bitterness-enhancing beer flavor of the present invention had a clearly enhanced bitterness and astringency compared to the non-alcoholic beer-flavored beverage containing the beer flavor without the addition of the present compound (A).

[0146] (Example 11) Extraction of the bitterness enhancer of the present invention from roasted green tea (a) Steam distillation process 100 kg of roasted green tea (roasted green tea made from first-grade tea) was packed into a column, and steam distillation was carried out by feeding steam at 100°C from the bottom of the column. The steam containing the target substance obtained from the top of the column was condensed in a cooling tube (15°C to 20°C), and 170 kg of distillate containing aroma components (170% by weight based on the green tea leaves) was obtained. The concentration of 1-ethyl-2-(1-pyrrolylmethyl)pyrrole (compound (A)) in the obtained distillate was 0.023 ppm.

[0147] (b) Adsorption process Next, 2 kg of salt was added to a 20 kg portion of the distillate, and salting out was performed by thoroughly dissolving the salt. The green tea aroma after salting out was passed through a 20 mL synthetic adsorbent (manufactured by Mitsubishi Chemical Corporation, product name "Sepabeads (registered trademark) SP-207") packed in a column at a flow rate of 1 kg / h (SV=50 h). -1 ) and the aroma components were adsorbed onto a synthetic adsorbent.

[0148] (c) Cleaning process Next, 200 g of soft water was passed through the adsorbent to which the target substance had been adsorbed at a rate of 1 kg / h (SV=50 h -1 After that, 20 g of each of 10% by volume ethanol aqueous solution, 25% by volume ethanol aqueous solution, 50% by volume ethanol aqueous solution, and 75% by volume ethanol aqueous solution were successively passed through the column at a flow rate of 40 g / h (SV=2 h -1 ) and washed.

[0149] (d) Elution process Next, 20 g of 95% ethanol was passed through the tube at a flow rate of 40 g / h (SV=2 h -1 ), to obtain the tea extract.

[0150] (Analysis of Tea Extract) The quantitative analysis of 1-ethyl-2-(1-pyrrolylmethyl)pyrrole for each fraction (Fr.1 to Fr.5) of the obtained tea extract is shown in Table 9 below. The measurement was performed by diluting each of the obtained fractions in a measuring flask, filtering the resulting sample through a membrane filter with 0.45 μm openings, and performing multiple reaction monitoring using LC-MS / MS (manufactured by AB Sciex Co., Ltd.) to compare with a standard product obtained by synthesis in advance at m / z = 175 → 80. The analysis conditions for LC-MS / MS were as follows. ≪LC-MS / MS analysis conditions≫ LC column: GL Sciences InertSustein C18 (3 μm, 4.6 × 150 mm) Eluent A: Ultrapure water (0.1% by volume formic acid) Eluent B: Acetonitrile (0.1% by volume formic acid) (Concentration gradient conditions) Time Eluent A Eluent B 0.0 minutes 90% 10% 30.0 minutes 10% 90% 40.0 minutes 10% 90% 40.1 minutes 90% 10% 50.0 minutes 90% 10% In addition, the purity (GC AREA%) of 1-ethyl-2-(1-pyrrolylmethyl)pyrrole was measured for each fraction (Fr.1 to Fr.5) of the obtained tea extract, and the results are shown in Table 9 below. The measurement was performed using a GC / MS (apparatus name: GC7890A / MSD5975C, manufactured by Agilent Technologies, Inc.). The GC / MS analysis conditions were as follows: ≪GC / MS analysis conditions≫ GC column for GC / MS measurement: GL Sciences InertCap-WAX (long Length 60m, inner diameter 0.25mm, liquid layer thickness 0.25μm) (GC conditions) Temperature rise conditions: 40℃~230℃, 5.0℃ / min temperature rise, 20min hold Column flow rate: 1.0 mL / min.

[0151] [Table 9]

[0152] As shown in Table 9 above, it was found that the tea extract obtained by the above method contained 1-ethyl-2-(1-pyrrolylmethyl)pyrrole at a high concentration.

[0153] The above-mentioned Fr. 2 was diluted with 95% by volume of ethanol to give a 1-ethyl-2-(1-pyrrolylmethyl)pyrrole concentration of 10 ppm, thereby obtaining a bitterness enhancer (Product 3 of the present invention) which is a natural extract.

[0154] (Example 12) Addition of the bitterness enhancer (natural extract) of the present invention to unsweetened black coffee The unsterilized coffee beverage concentrate used in Example 7 was divided into portions to prepare either an additive-free or an additive-free version of the present invention 3 at 0.1 ppm. The portions were heated to 90°C, filled into cans at 190 g each, and retort sterilized (121°C, 20 minutes, F=39) to obtain canned unsweetened black coffee. Each unsweetened black coffee was evaluated by 20 panelists for bitterness (including astringency) based on the additive-free version, with the following score: -1 point: slightly decreased, 0 point: no change felt, 1 point: slightly increased, 2 points: clearly increased, 3 points: significantly increased. The average scores are shown in Table 10.

[0155] [Table 10]

[0156] As shown in Table 10, the unsweetened black coffee containing the bitterness enhancer (natural extract) of Invention Product 3 had a clearly enhanced bitterness compared to the unsweetened black coffee without Invention Product 3 added.

[0157] (Example 13) Preparation of beer flavor for enhancing bitterness sensation containing the bitterness sensation enhancer (natural extract) of the present invention The present invention product 3 (see Example 10) was added at 0.01% to the comparative product 2 (see Table 6) of Example 8 to prepare a beer flavor for enhancing bitterness sensation of the present invention (Product 4 of the present invention).

[0158] (Example 14) Addition of the beer flavor for enhancing bitterness of the present invention to a beer-flavored beverage A non-alcoholic beer-flavored beverage was prepared according to the formulation in Table 11 below.

[0159] [Table 11]

[0160] Twenty panelists rated each non-alcoholic beer-flavored beverage for bitterness (including astringency) based on the bitterness of the non-alcoholic beer-flavored beverage containing Comparative Product 2, with the following scale: -1 point: slightly decreased, 0 point: no change was felt, 1 point: slightly increased, 2 points: clearly increased, 3 points: significantly increased. The average scores are shown in Table 12.

[0161] [Table 12] As shown in Table 12, the non-alcoholic beer-flavored beverage containing the beer flavor for enhancing bitterness of the present invention had a clearly enhanced bitterness compared to the non-alcoholic beer-flavored beverage containing the beer flavor without the addition of the product of the present invention.

Claims

1. The following formula (1): 【Chemistry 1】 [In the above formula (1), R １ is a linear or branched alkyl group having 1 to 3 carbon atoms or a hydroxyl group, R ２ is a 1-pyrrolyl group, a 2-pyrrolyl group or a 3-pyrrolyl group] as an active ingredient.

2. 2. The bitterness enhancer according to claim 1, which is a natural extract.

3. 3. The bitterness sensation enhancer according to claim 2, wherein the raw material of the natural extract is at least one selected from the group consisting of green tea, oolong tea, black tea and cereal tea.

4. A method for enhancing the bitterness sensation of a food or drink, comprising a step of adding the bitterness sensation enhancer according to any one of claims 1 to 3 to the food or drink.

5. A flavor imparting composition for enhancing bitterness sensation, comprising the bitterness sensation enhancer according to any one of claims 1 to 3.

6. A method for enhancing the bitterness sensation of a food or drink, comprising the step of adding the flavor-imparting composition for enhancing the bitterness sensation according to claim 5 to the food or drink.

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