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] This invention relates to an agent for enhancing the bitterness of food and beverages. [Background technology]

[0002] The five basic tastes are sweet, sour, salty, umami, and bitter. Of these, bitterness is often perceived as a signal of toxins in plants and is generally avoided. While excessive bitterness in food and beverages can be unpleasant, a moderate amount can often add depth and richness to the flavor. Examples of such foods include coffee, chocolate, and beer, all of which are considered characteristic tastes of highly palatable foods.

[0003] As an example of imparting bitterness to food and beverages, Patent Document 1 describes a bittering agent to beer-flavored beverages. The bittering agent in Patent Document 1 includes hop-derived components, kwashin, naringin, wormwood (or wormwood extract or wormwood flavoring), citrus extract, bitter oak extract, coffee extract, tea extract, bitter melon extract, lotus germ extract, aloe vera extract, rosemary extract, reishi mushroom extract, laurel extract, sage extract, caraway extract, isohumulones, and reduced isohumulones, etc. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2019 / 193675 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, conventionally proposed bitterness-imparting agents impart bitterness as a taste and do not adequately address the growing demand for improving the flavor of diverse foods and beverages. Therefore, the inventors focused not on bitterness as a taste, but on the sensation of bitterness as an aroma, and developed a versatile bitterness-enhancing agent that can enhance the bitterness of bitter foods and beverages through this sensation of bitterness.

[0006] Therefore, the object of the present invention is to provide a novel bitterness enhancer, a bitterness-enhancing flavoring composition containing the bitterness enhancer, and a method for enhancing the bitterness of food and beverages. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the present inventors have discovered that pyrrole analogs, which are compounds represented by the following formula (1), exhibit an excellent bitterness-enhancing effect on bitter foods and beverages, and have completed the present invention.

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

[0009] [ka]

[0010] A bitterness enhancer containing as an active ingredient a compound represented by the above formula (1), where R1 is a linear or branched alkyl group or hydroxyl group having 1 to 3 carbon atoms, and R2 is a 1-pyrrolyl group, a 2-pyrrolyl group, or a 3-pyrrolyl group. (2) A bitterness enhancer described in (1), which is a natural extract. (3) The bitterness 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 grain tea. (4) A method for enhancing the bitterness of food and beverages, comprising the step of adding a bitterness-enhancing agent described in any one of (1) to (3) to food and beverages. A flavoring composition for enhancing bitter taste, containing the bitter taste enhancer according to any one of (1) to (3). (6) A method for enhancing the bitter taste of food and drink, comprising the step of adding the flavoring composition for enhancing bitter taste according to (5) to the food and drink. [Advantages of the Invention]

[0011] According to the present invention, it is possible to provide a novel bitter taste enhancer, a flavoring composition for enhancing bitter taste containing the bitter taste enhancer, and a method for enhancing the bitter taste of food and drink.

[0012] Hereinafter, an embodiment of the present invention will be described in detail. In this specification, "~" means a range including the lower limit value and the upper limit value, and "concentration (ppm, ppb, ppt)" and "%" represent "mass concentration" and "mass percentage concentration", respectively, unless otherwise specified. Further, in this specification, "flavor" means one or more kinds of sensations that can be changed by aroma (scent), typically sensations including smell and / or taste.

[0013] In this specification, the term "bitter taste" includes, in addition to bitter taste, astringency or astringent taste, or a flavor combining these.

[0014] In this specification, the term "enhancing bitter taste" means that when the bitter taste enhancer of the present invention is contained in a food or drink that originally has a bitter taste, the sensation corresponding to the bitter taste is enhanced by the flavor.

[0015] Also, in this specification, the flavor of food and drink may be referred to as flavor. Further, in this specification, "addition" includes at least one of simply adding to an object by spraying, dropping, etc., and mixing with an object.

[0016] (Bitter Taste Enhancer) The bitter taste enhancer according to an embodiment of the present invention (hereinafter, may be referred to as the present bitter taste enhancer) has the following formula (1):

[0017] [Chemical formula]

[0018] [In the above formula (1), 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], a compound represented by (hereinafter, may be referred to as the compound of the present case) is used as an active ingredient.

[0019] According to Japanese Patent Application Laid-Open No. 2019-26565, the compound of the present case is described as a compound that contributes to a fragrant roasting feeling, but it has not been known at all as a compound that can be used as a bitterness intensifier.

[0020] In this regard, as a result of intensive studies, the present inventors have found that the compound of the present case is an active ingredient of a bitterness intensifier for foods and beverages. And it has been found that the bitterness intensifier containing a predetermined amount of the compound of the present case can enhance the bitterness of a food or beverage having bitterness by adding it to the food or beverage having bitterness, as shown in an example in the following examples.

[0021] (The compound of the present case) The compound of the present case may be synthesized or derived from a natural product, and can be obtained by any method that can be performed by those skilled in the art. The obtained compound of the present case may be further purified using means such as column chromatography or vacuum distillation as necessary.

[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 -OH group or hydroxy 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 them, an alkyl group and a hydroxyl group having a small number of carbon atoms are preferable. 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 formula (1) above, 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 formulas (a) to (c) below, "*" indicates a binding site):

[0025] [ka] In particular, from the viewpoint of simplifying the manufacturing process and obtaining a compound with a higher bitterness-enhancing effect (one that can exhibit a bitterness-enhancing effect with a small amount), R2 is preferably a 1-pyrrolyl group (formula (a) above) or a 2-pyrrolyl group (formula (b) above), and is especially preferably a 1-pyrrolyl group (formula (a) above). When R2 is a 1-pyrrolyl group, the polarity of the compound is relatively lower compared to when it is a 2-pyrrolyl group or a 3-pyrrolyl group, resulting in lower melting and boiling points, which is thought to further enhance the bitterness-enhancing effect.

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

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

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

[0029] [ka]

[0030] The synthesis of the above-mentioned compound can be carried out, for example, by appropriately modifying known methods or by combining them, or by following the method described in Japanese Patent Application Publication No. 2019-26565. That is, the above-mentioned compound can be synthesized by simultaneously carrying out an Appel reaction and an addition reaction using 1-alkylpyrrole and 1-hydroxymethylpyrrole. Alternatively, a method may be used in which the hydroxyl group of 1-hydroxymethylpyrrole is halogenated by a known method to obtain a halide, and then a coupling reaction is carried out between the halide and 1-alkylpyrrole. Furthermore, a method may be used in which a coupling reaction is carried out between 1-alkyl-2-hydroxymethylpyrrole and pyrrole.

[0031] (Natural extract) Furthermore, the method for producing the compound in question is not particularly limited, and for example, it 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, but for example, it can be carried out according to the method described in Japanese Patent Application Publication No. 2019-156993.

[0032] More specifically, for example, the process of obtaining a distillate by steam distillation of natural raw materials. Adsorption step of bringing the distillate into contact with an adsorbent, After the adsorption step, a washing step is performed in which an aqueous alcohol solution with a concentration of more than 0% by volume and less than 95% by volume is passed through the adsorbent. A composition containing the compound in question at a high concentration can be prepared by a method for producing a purified natural extract, which includes, after the washing step, an elution step in which the components adsorbed on the adsorbent are eluted with an aqueous alcohol solution with a concentration of 95% by volume or more.

[0033] (natural raw materials) There are no particular restrictions on the natural raw materials used in the production of the aforementioned natural extracts, but examples include processed products of the evergreen tree Camellia sinensis (L) O. Kuntze, grain tea, and herbal tea. Examples of processed products of Camellia sinensis (L) O. Kuntze include fresh leaves obtained from the buds, leaves, and stems of the Camellia sinensis, as well as processed unfermented tea, semi-fermented tea, and fermented tea. Examples of unfermented tea include green tea (sencha, gyokuro, kabusecha, bancha, tamaryokucha, matcha, hojicha, tencha, etc.); examples of semi-fermented tea include oolong tea and baozhong tea; and examples of fermented tea include black tea and pu-erh tea.

[0034] Other examples of grain teas include barley tea (roasted barley), roasted malt, adlay tea (roasted adlay), roasted brown rice, buckwheat tea (roasted buckwheat), roasted corn, roasted sesame, roasted quinoa, roasted amaranth, roasted millet, roasted barnyard millet, roasted foxtail millet, and roasted soybeans.

[0035] Examples of herbal teas include senna tea, Gynostemma pentaphyllum tea, plantain tea, cherry blossom tea, sweet tea, persimmon leaf tea, kelp tea, pine needle tea, Angelica keiskei tea, guava tea, loquat leaf tea, aloe tea, turmeric tea, horsetail tea, safflower tea, saffron tea, comfrey tea, goji berry tea, mugwort tea, ginkgo leaf tea, quince tea, mulberry leaf tea, burdock tea, Aralia elata tea, dandelion tea, sword bean tea, elderberry tea, privet tea, Japanese laurel tea, and monk fruit tea.

[0036] In particular, for the purpose of obtaining an extract with a high content of the compound in question, the natural raw material preferably includes at least one selected from the group consisting of green tea, oolong tea, black tea, and grain tea, and it is especially preferable to obtain the extract using roasted tea. Here, "roasted tea" means tea that has been heated and dried without using oil or water as a heat transfer medium. For the purpose of obtaining an extract with a high content of the compound in question, it is especially preferable to obtain the extract using roasted tea.

[0037] (Steam distillation process) Steam distillation can be carried out using known methods or by modifying them as appropriate. For example, steam can be blown into the bottom of a steam distillation pot containing the natural raw materials, or the water in the steam distillation pot can be boiled and the distillate vapor can be cooled by a condenser connected to the distillation side at the top. Through such operations, a distillate containing aromatic components can be collected as a condensate.

[0038] When performing steam distillation, any of the following methods may be used: pressurized steam distillation, atmospheric steam distillation, or reduced-pressure steam distillation. However, from the viewpoint of reducing the loss of aromatic components, it is preferable to perform steam distillation at atmospheric pressure.

[0039] In steam distillation, the steam temperature, steam flow rate (supply rate), distillation time, condensation (cooling) temperature, and effluent volume can be arbitrarily set according to the type of natural raw material used for extraction. For example, the steam temperature may be 80-130°C, the condensation (cooling) temperature 0-50°C, and the effluent volume 0.1-5 times the total weight of the natural raw material, but it is not limited to this range.

[0040] Alternatively, a countercurrent gas-liquid catalytic distillation method, an improved version of steam distillation, may be used. Specifically, a pre-prepared slurry of the natural raw material (a suspension of the natural raw material and water) is placed at the top of the column.

[0041] Next, the slurry enters a rotating cone, where centrifugal force from the cone's rotation causes it to form a thin liquid layer, which falls onto a stationary cone and then moves to the next rotating cone. The slurry repeats this movement and moves to the bottom of the column, while steam is injected from the bottom of the column. The steam moves to the top of the column, recovering aroma components, and the distillate can be obtained by cooling the steam that flows out from the top of the column.

[0042] An example of a device capable of performing the above method is a spinning cone column (SCC) manufactured by Flavourtech. There are no particular restrictions on the operating conditions of the device, and those skilled in the art can set them as appropriate.

[0043] (Adsorption process) In the adsorption process, the distillate is brought into contact with an adsorbent. As a result, the aroma components contained in the distillate are adsorbed by the adsorbent.

[0044] The distillate can be used as is, or after adjusting it to any desired concentration with water or other liquids. Before contacting the distillate with the adsorbent, pretreatment such as concentration, filtration, decantation, centrifugation, or salting out may be performed. Such pretreatment allows for efficient adsorption of aroma components onto the adsorbent. These pretreatment methods are not particularly limited and can be carried out using known methods or by modifying them as appropriate.

[0045] A known method can be used to bring the distillate obtained in the above process into contact with the adsorbent. For example, a method of passing the distillate through a column packed with the adsorbent, or a method of dispersing the adsorbent in the distillate, stirring, and then separating the adsorbent by means of filtration or other means can be used. From the viewpoint of work efficiency, the former method is preferred.

[0046] When using a column, there are no particular restrictions on the flow rate of the distillate, but from the viewpoint of sufficient adsorption of aroma components, the space velocity (SV) should be 1 to 500 h. -1 Preferably, 5 to 200 hours -1 It is more preferable that it be 10 to 100 hours -1 It is particularly preferable that this is the case. Space velocity (SV) is a unit that indicates how many times the volume of liquid relative to the volume of the adsorbent is passed through per hour. In this case, the column may be under atmospheric pressure or under pressurized pressure. Furthermore, there are no particular restrictions on the amount of distillate that comes into contact with the adsorbent, but from the viewpoint of reducing the loss of aroma components, it is preferable that it be 100 to 5000 times (volume) the adsorbent, and more preferably 500 to 2000 times (volume).

[0047] The adsorbent used in this process is not particularly limited; for example, synthetic adsorbents or silica gel can be used. However, due to its excellent durability and the ability to obtain a natural extract containing the compound in high concentration and high purity, it is preferable to use a synthetic adsorbent.

[0048] While there are no particular limitations on the synthetic adsorbents that can be used, it is preferable to use synthetic adsorbents based on organic resins because they have excellent affinity with the target compound 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 these, 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] Commercially available synthetic adsorbents can be used, such as Diaion® HP20, HP21; Sepabeads® SP825L, SP850, SP700, SP70, SP207 (all aromatic resins, manufactured by Mitsubishi Chemical Corporation); Amberlite® XAD-2, XAD-4, XAD-2000 (all aromatic resins, manufactured by Organo Corporation); and Diaion® HP1MG, HP2MG (both methacrylic acid ester resins, manufactured by Mitsubishi Chemical Corporation).

[0051] In particular, from the viewpoint of having excellent affinity with the target compound, it is preferable to use Sepabeads® SP207, a synthetic adsorbent based on a modified styrene-divinylbenzene copolymer in which bromine atoms are bonded to an aromatic resin.

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

[0053] The adsorbent may be washed with water or a mixed solvent of water and an organic solvent before contact with the distillate. The organic solvent is preferably miscible with water and includes, for example, 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 individually or in combination of two or more.

[0054] (Washing process) The washing step is performed after the adsorption step. In the washing step, an aqueous alcohol solution (hereinafter also referred to simply as "low-concentration aqueous alcohol solution") with a concentration of more than 0% by volume and less than 95% by volume is passed over the adsorbent on which the aroma components have been adsorbed. By performing such a washing step before the elution step, impurities contained in the distillate can be effectively removed, and the purity of the compound in question in the resulting natural extract can be improved.

[0055] In the washing process, if washing is performed with water only (i.e., if the alcohol concentration in the alcohol aqueous solution used is 0% by volume) or if the washing process is not performed at all, impurities cannot be sufficiently removed, resulting in a decrease in the purity of the compound in question in the resulting natural extract, which is undesirable.

[0056] On the other hand, if the alcohol concentration in the aqueous alcohol solution used in this process is 95% by volume or higher, the compound adsorbed on the adsorbent will leach out, making it difficult to obtain the compound at a high concentration.

[0057] In the washing process, before passing an alcohol aqueous solution with an alcohol concentration exceeding 0% by volume but less than 95% by volume through it, washing may be performed by passing only water through it (pre-washing). There are no particular restrictions on the rate of liquid (water) passage at this time, but from the viewpoint of sufficiently adsorbing fragrance components, a space velocity (SV) of 1 to 100 h is recommended. -1 Preferably, 10 to 80 hours -1 It is more preferable that it be 30-60h -1 It is particularly preferable that this is the case. In this case, the column may be under atmospheric pressure or under pressurized pressure. Furthermore, there are no particular restrictions on the amount of water that is passed through the adsorbent during the pre-wash, but from the viewpoint of sufficiently removing impurities while reducing the loss of aroma components, it is preferable that the amount of water is 0.5 to 100 times (volume) the adsorbent, and more preferably 1 to 50 times (volume).

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

[0059] In this process, the concentration of the low-concentration alcohol aqueous solution passed through may be constant or varied. To concentrate the compound with higher purity, it is preferable in this process to pass through multiple low-concentration alcohol aqueous solutions with varying alcohol concentrations so that the alcohol concentration increases in stages.

[0060] In this process, it is preferable to use a low-concentration alcohol aqueous solution that is gradually increased in concentration, with the alcohol concentration changing in increments of 10 to 30% by volume.

[0061] A method of passing a low-concentration aqueous alcohol solution through an adsorbent adsorbed with an aroma component can use a known technique. For example, a method of passing a low-concentration aqueous alcohol solution through a column filled with an adsorbent (the adsorbent that adsorbed the aroma component in the above adsorption step) is used. The flow rate at this time is not particularly limited, but from the viewpoint of sufficiently removing impurities, the space velocity (SV) is preferably 1 to 100 h -1 and more preferably 1.5 to 50 h -1 and even more preferably 2 to 30 h -1 is particularly preferred. In this case, the inside of the column may be at normal pressure or in a pressurized state. Also, the amount of the low-concentration aqueous alcohol solution passed through the adsorbent is not particularly limited, but from the viewpoint of sufficiently removing impurities while reducing the loss of the aroma component, it is preferably 0.5 to 100 times (volume) with respect to the adsorbent, and more preferably 1 to 50 times (volume).

[0062] The passing of the low-concentration aqueous alcohol solution is preferably carried out while measuring the content of the components contained in the effluent and while confirming that the outflow amount of the target compound of the present case is small.

[0063] As the alcohol contained in the low-concentration aqueous alcohol solution, lower alcohols are preferred from the viewpoints of being easily miscible with water and easily eluting impurities, and methanol, ethanol, n-propanol, isopropanol, etc. can be used. Among them, it is preferable to use ethanol or n-propanol in terms of easily controlling the elution property of the target compound of the present case and the safety in the food and beverage use of the obtained natural extract, and it is particularly preferable to use ethanol. Note that the alcohol contained in the low-concentration aqueous alcohol solution may be used alone or in combination of two or more.

[0064] Also, 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 step) The elution step is performed after the washing step described above. In the elution step, the components (aroma components) adsorbed on the adsorbent are eluted with an aqueous alcohol solution with a concentration of 95% by volume or more (hereinafter also referred to simply as "high-concentration aqueous alcohol solution"). By performing such an elution step, a natural extract containing the compound in question at a high concentration can be obtained.

[0066] In the elution process, if elution is performed with an alcohol aqueous solution of less than 95% by volume, the concentration of the target compound in the resulting natural extract decreases. Furthermore, the amount of alcohol aqueous solution required to recover the target compound adsorbed on the adsorbent increases, which is undesirable from the standpoint of work efficiency.

[0067] In order to obtain a natural extract containing the target compound in a higher concentration and with 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] Known methods can be used to elute aroma components adsorbed on an adsorbent using a high-concentration alcohol aqueous solution. For example, a method of passing a high-concentration alcohol aqueous solution through an adsorbent packed in a column, or a method of dispersing the adsorbent in a high-concentration alcohol aqueous solution, stirring, and then separating the adsorbent by means of filtration or other means can be used. From the viewpoint of work efficiency, the former method is preferred.

[0069] When using a column, there are no particular restrictions on the flow rate of the high-concentration alcohol aqueous solution, but from the viewpoint of sufficiently eluting the aroma components, the space velocity (SV) should be 0.1 to 10 h. -1It is preferable that this is the case. In this case, the column may be under atmospheric pressure or under pressurized pressure. Furthermore, there are no particular restrictions on the amount of high-concentration aqueous alcohol solution to be passed through, but from the viewpoint of suppressing the residue of aroma components on the adsorbent, it is preferable that the amount is 0.1 to 100 times (volume) relative to the adsorbent, and more preferably 0.5 to 30 times (volume). If the amount of high-concentration aqueous alcohol solution passed through is 100 times or less, and even more preferably 30 times or less, a natural extract in which the target compound is concentrated to an extremely high concentration can be obtained.

[0070] As the alcohol contained in the high-concentration aqueous alcohol solution, lower alcohols are preferred because they are easily miscible with water and readily elute the target compound. Examples include methanol, ethanol, n-propanol, and isopropanol. In particular, ethanol or n-propanol is preferred, and ethanol is especially preferred, as it promotes the elution of the target compound and ensures the safety of the resulting natural product for use in food and beverages. The alcohol contained in the high-concentration aqueous alcohol solution may be used alone or as a mixture of two or more types.

[0071] Furthermore, 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. In addition, organic solvents other than alcohol may be mixed into the high-concentration alcohol aqueous solution used in the present invention as appropriate. The organic solvent is not particularly limited, but examples 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 process can be used as is as the bitterness enhancer of the present invention. Alternatively, the concentration and / or purity of the compound can be increased by combining methods such as solvent removal by concentration, distillation, and various chromatography techniques with the eluate to produce the bitterness enhancer of the present invention.

[0073] The bitterness enhancer of the present invention, which is a natural extract, preferably contains a concentration of the compound of the present invention 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 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 in question may consist solely of the compound in question, or it may contain solvents or other components as long as it contains a predetermined amount of the compound in question. The concentration of the compound in question in the bitterness enhancer can be arbitrarily determined depending on the target to which the bitterness enhancer is added. Examples of the concentration of the compound in question include a range of 0.1 ppb to 100%, preferably 0.5 ppb to 10%, and more preferably 2 ppb to 1%, relative to the total mass of the bitterness enhancer. More specifically, the lower limit is set to one of the following: 0.1ppb, 0.2ppb, 0.5ppb, 1ppb, 2ppb, 5ppb, 10ppb, 20ppb, 50ppb, 100ppb, 200ppb, 500ppb, 1ppm, 2ppm, 5ppm, 10ppm, 20ppm, 50ppm, 100ppm, 0.1%, 0.2%, 0.5%, 1%, 2%, 5%, 10%, 20%, 50%, and the upper limit is set to 100%, 50%, 20%, 10%. The values ​​can be expressed as %, 5%, 2%, 1%, 0.5%, 0.2%, 0.1%, 500ppm, 200ppm, 100ppm, 50ppm, 20ppm, 10ppm, 5ppm, 2ppm, 1ppm, 500ppb, 200ppb, 100ppb, 50ppb, 20ppb, 10ppb, 5ppb, 2ppb, or 1ppb, and can be within any combination of these lower and upper limits, but are not limited to these.

[0075] Examples of products to which this bitterness-enhancing agent can be added include flavor-imparting compositions (including fragrance compositions) and food and beverages. Details of each product to which it can be added will be described later.

[0076] (Flavor-imparting composition for enhancing bitterness) The bitterness-enhancing composition may be added to food and beverages on its own, or it may be added to food and beverages in combination with one or more water-soluble and oil-soluble flavors, emulsified flavor compositions, any flavor compounds, and natural essential oils (for example, flavor compounds described in the aforementioned "Japan Patent Office Gazette, Collection of Well-Known and Conventional Technologies (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 "flavor-imparting composition").

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

[0078] In the composition, the amount of the bitterness-enhancing agent added to the flavor-imparting composition to be added should be an effective amount that provides a bitterness-enhancing effect through the compound included as an active ingredient, and can be arbitrarily set depending on the type and form of the flavor-imparting composition to which it is added. Specific examples of the concentration of the compound in the bitterness-enhancing flavor-imparting composition can be the same concentration range as described in the "Compound" section above.

[0079] (Flavor-imparting composition) The following describes the flavor-imparting compositions to which the bitterness enhancer in this case is to be added. Flavor-imparting compositions provide excellent flavor-imparting effects when added to various articles. The articles to which the flavor-imparting compositions are to be added are not particularly limited, but other flavor-imparting compositions or food and beverages can be given as examples. Examples of flavor-imparting compositions include fragrance compositions, flavor improvers, flavor modifiers, flavor imparters, flavor improvers, flavor modifiers, taste imparters, taste improvers, and taste modifiers.

[0080] The bitterness enhancer in this case can be added to a flavoring composition to impart a bitter sensation. In other words, a flavoring composition to which the bitterness enhancer in this case has been added can be used as a flavoring composition for enhancing bitterness.

[0081] Furthermore, by composing the bitterness-enhancing agent in question with the compound in question and a compound capable of imparting flavor (for example, a flavoring compound), the bitterness-enhancing agent in question can also be used as a flavor-imparting composition for enhancing bitterness.

[0082] A specific example of a flavor composition, which is one form of a flavor-imparting composition, is a flavor composition for food and beverages (also called a flavor composition). As mentioned above, examples of articles to which it is added include food and beverages.

[0083] Flavoring compositions may contain the following compounds or components. Examples include various types of fragrance compounds or fragrance compositions, oil-soluble pigments, vitamins, functional substances, fish extracts, livestock extracts, plant extracts, yeast extracts, animal and plant proteins, animal and plant protein hydrolysates, starch, dextrin, sugars, amino acids, nucleic acids, organic acids, solvents, etc. For example, natural essential oils, natural fragrances, and synthetic fragrances described in "Japan Patent Office Gazette, Collection of Well-Known and Conventional Technologies (Fragrances) Part II Food Fragrances, published January 14, 2000," "Survey on the Actual Use of Food Fragrance Compounds in Japan" (FY2000 Ministry of Health Science Research Report, Japan Fragrance Manufacturers Association, published March 2001), and "Synthetic Fragrance Chemistry and Product Knowledge" (Revised and Enlarged Edition published December 20, 2016, edited by the Synthetic Fragrance Editorial Committee, Chemical Daily Co., Ltd.) can be cited.

[0084] Specific examples of synthetic fragrance compounds include hydrocarbon compounds such as monoterpenes like 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 alcohol compounds 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, tetrahydromyrcenolic acid, 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 aldehyde compounds 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, myrthenal, and perillaldehyde; and aromatic aldehydes such as benzaldehyde, cinnamylaldehyde, vanillin, ethyl vanillin, heliotropin, and p-tolylaldehyde.

[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, ethylmaltol, cyclotene, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone; terpene ketones such as carvone, menthone, and nootkatone; ketones derived from terpene decomposition products such as α-ionone, β-ionone, and β-damascenone; and aromatic ketones such as raspberry ketone.

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

[0089] Examples of ester compounds 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 lactone compounds include saturated lactones such as γ-decalactone, γ-dodecalactone, δ-decalactone, and δ-dodecalactone, and unsaturated lactones such as 7-decene-4-olide and 2-decene-5-olide.

[0091] Examples of acidic 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 nitrogen-containing compounds include indole, skatole, pyridine, alkyl-substituted pyrazines, methyl anthranilate, and trimethylpyrazine.

[0093] Examples of sulfur-containing compounds include methanethiol, dimethyl sulfide, dimethyl disulfide, allyl isothiocyanate, 3-methyl-2-buten-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] Examples of 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 plant and animal extracts include extracts of herbs or spices, or extracts of coffee, green tea, black tea, or oolong tea, as well as milk or dairy products and various enzyme hydrolysates such as lipases or proteases thereof.

[0096] The form of the fragrance composition is not particularly limited, and examples include water-soluble fragrance compositions, oil-soluble fragrance compositions, emulsified fragrance compositions, and powdered fragrance compositions. Suitable forms of the fragrance composition include solutions obtained by dissolving the bitterness enhancer or other components in a water-soluble or oil-soluble solvent, emulsified formulations, powder formulations, or other solid formulations (such as solid fats).

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

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

[0099] Furthermore, to obtain an emulsified formulation, the flavoring composition can be emulsified with a water-soluble solvent and an emulsifier. The method of emulsifying the flavoring composition is not particularly limited, and an emulsified liquid with excellent stability can be obtained by emulsifying it using emulsifiers such as various types of emulsifiers conventionally used in food and beverages, for example, fatty acid monoglycerides, fatty acid diglycerides, fatty acid triglycerides, propylene glycol fatty acid esters, sucrose fatty acid esters, polyglycerin fatty acid esters, lecithin, modified 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, casein quillaja saponin, or sodium caseinate, using a homomixer, colloid mill, rotary disc homogenizer, high-pressure homogenizer, etc. The amount of these emulsifiers used is not strictly limited and can be varied over a wide range depending on the type of emulsifier used, but generally, an amount 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 in question is appropriate. In addition, in order to stabilize the emulsified state, in addition to water, one or more types of polyhydric alcohols such as glycerin, propylene glycol, sorbitol, maltitol, sucrose, glucose, trehalose, sugar solution, and reduced starch syrup may be added to the emulsified liquid.

[0100] Furthermore, the resulting emulsified liquid can be dried to produce a powder formulation if desired. During the powdering process, sugars such as gum arabic, trehalose, dextrin, sugar, lactose, glucose, starch syrup, and reduced starch syrup may be added as needed. The amounts used can be appropriately selected according to the desired characteristics of the powder formulation.

[0101] In addition to the above, the present fragrance composition may contain, as necessary, other components commonly used in fragrance compositions. For example, it may contain solvents such as water and ethanol, and fragrance fixatives such as ethylene glycol, propylene glycol, dipropylene glycol, glycerin, hexylene glycol, benzyl benzoate, triethyl citrate, diethyl phthalate, Harcolin, medium-chain triglyceride, and medium-chain diglyceride.

[0102] (Methods for enhancing the bitterness of food and beverages) A method for enhancing the bitterness of food and beverages according to one embodiment of the present invention (hereinafter referred to as "the bitterness enhancement method") includes the step of adding the bitterness enhancing agent or a bitterness enhancing flavor composition to food and beverages.

[0103] By adding an effective amount of this bitterness-enhancing composition, or the bitterness-enhancing flavor-imparting composition, to a bitter food or beverage, the bitterness of the food or beverage can be enhanced.

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

[0105] The preferred concentration of the compound in question is, when the substance is added to food or beverage, based on the total mass of the food or beverage, a bitter taste can be imparted within the range of at least 0.01 ppt to 100 ppt, and a bitter taste can be imparted more effectively within the range of 0.05 ppt to 20 ppt. More specifically, the lower limit can 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, or 50 ppt, and the upper limit can 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, or 0.02 ppt, and the concentration can be within any combination of these lower and upper limits, but is not limited to these.

[0106] The method by which the bitterness-enhancing composition is added to food or beverages is not particularly limited. Furthermore, there are no particular limitations on the timing of adding the bitterness-enhancing composition to food and beverages.

[0107] (Foods with a bitter taste) The food and beverages targeted by this method for enhancing the bitterness of food and beverages, which is one aspect of the present invention, are not particularly limited as long as they have a bitter taste. Examples include: rice crackers, arare, okoshi, mochi, manju, uiro, bean paste, yokan, mizuyokan, kintama, jelly, castella, candy, biscuits, crackers, potato chips, cookies, pies, pudding, buttercream, custard cream, cream puffs, waffles, sponge cake, donuts, chocolate, chewing gum, caramel, candy, peanut paste or other pastes, and other confectionery; bread, udon, ramen, Chinese noodles, sushi, gomoku-meshi, fried rice, pilaf, gyoza wrappers, shumai wrappers, okonomiyaki, takoyaki, and other breads, noodles, rice dishes, and other grains; pickled vegetables such as nukazuke, umeboshi, fukujinzuke, bettara-zuke, senmaizuke, rakkyo, miso-zuke, takuan-zuke, and the base ingredients for these pickles, etc. Pickled seafood; fish such as mackerel, sardines, saury, salmon, tuna, bonito, whale, flounder, sand eel, sweetfish, squid such as Japanese flying squid, spear squid, cuttlefish, firefly squid, octopus such as common octopus, baby octopus, shrimp such as kuruma prawn, spot prawn, spiny lobster, black tiger prawn, crabs such as king crab, snow crab, swimming crab, hairy crab, shellfish such as clams, cockles, scallops, oysters, mussels, and other seafood; canned goods, boiled fish, Processed seafood products such as tsukudani, surimi, processed fish products (chikuwa, kamaboko, fried kamaboko, crab leg kamaboko, etc.), fried foods, tempura, etc.; meat products such as chicken, pork, beef, lamb, horse meat, etc.; processed meat products such as curry, stew, beef stew, Hayashi rice sauce, meat sauce, mapo tofu, hamburgers, dumplings, kamameshi mix, soups (corn soup, tomato soup, consommé soup, etc.), meatballs, braised pork, canned meat, etc.Table salt, seasoned salt, soy sauce, powdered soy sauce, miso, powdered miso, moromi, hishio, furikake, ochazuke mix, margarine, mayonnaise, dressing, vinegar, sanbaizu, powdered sushi vinegar, Chinese seasoning mix, tempura dipping sauce, noodle soup (kombu dashi or katsuobushi dashi, etc.), sauces (medium-thick sauce, tomato sauce, etc.), ketchup, yakiniku sauce, curry roux, stew mix, soup base, dashi base (kombu dashi or katsuobushi dashi, etc.), compound seasonings, new mirin, fried chicken flour, takoyaki flour, etc. Seasonings such as powdered sugar, and animal or plant-based broth-flavored foods and beverages to which these seasonings have been added; dairy products such as cheese, yogurt, and butter; various fermented products of various microorganisms such as brewer's yeast, baker's yeast, and lactic acid bacteria; simmered dishes such as boiled vegetables, Chikuzen-ni, Oden, and hot pot; ingredients and side dishes for take-out bento boxes; fruit juices and soft drinks containing fruit juice, such as apples, grapes, and citrus fruits (grapefruit, oranges, lemons, etc.), and fruit pulp drinks and fruit drinks containing fruit pulp. Foods; vegetables such as tomatoes, bell peppers, celery, melons, bitter melons, carrots, potatoes, asparagus, bracken, and fiddlehead ferns, as well as vegetable-based beverages and vegetable soups containing these vegetables; beverages such as coffee drinks, cocoa drinks, green tea, black tea, oolong tea, and other tea-based beverages, cola drinks, carbonated drinks (including ciders with various citrus flavors), and lactic acid bacteria beverages; beverages containing medicinal herbs and herbs; functional beverages such as sports drinks, honey drinks, vitamin supplements, mineral supplements, nutritional drinks, nourishing drinks, and lactic acid bacteria beverages; non-alcoholic and alcohol-flavored beverages with an alcohol content of less than 1 vol% and flavored with various alcoholic beverages (beer, plum wine, chuhai, etc.); beer-flavored beverages such as wine, shochu, awamori, sake, beer, chuhai, cocktail drinks, sparkling wine, fruit wine, medicinal wine, and so-called "third beer," or alcoholic beverages containing these; and so on.

[0108] Of 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, kwassin, naringin, absinthin, absorvins, catechins, chlorogenic acids, momordicin, aloin, aloenin, barbaloin, quinine, wormwood extract, citrus extract, bitter oak extract, coffee extract, tea extract, bitter melon extract, lotus germ extract, aloe vera extract, rosemary extract, reishi mushroom 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. However, the present invention is not limited to these examples.

[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 Japanese Patent Publication No. 2019-26565. 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] (Example 2) Addition to water Compound (A) was added to water to the concentrations shown in Table 1, and the bitterness of the aqueous solution was evaluated by 20 expert panelists. The evaluation criteria were as follows: (Evaluation Criteria) -: I can't taste any bitterness at all. +: A slight bitterness can be detected. ++: A distinct bitterness is noticeable. +++: A strong bitter taste can be felt. They were also asked to describe their evaluation of the flavor and aroma 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 flavors were detected. On the other hand, when the concentration of compound (A) added to water was 20 ppt or more, a roasted flavor was detected as an alternative to bitterness, and this flavor intensified with increasing concentration. However, at all concentrations, no bitterness was detected with compound (A) alone.

[0114] (Example 1) Addition of the bitterness enhancer of the present invention (compound (A)) to an aqueous solution of diketopiperazine. Diketopiperazines are substances produced when amino acids are heated, and are known to be present in a wide range of foods and beverages, contributing to their bitterness. Therefore, we investigated the effect of the bitterness-enhancing agent of the present invention on cycloprolylvaline, one of the representative diketopiperazines. A 500 ppm aqueous solution of cycloprolylvaline (Fujifilm Wako Pure Chemical Industries, Ltd.) (approximately twice the bitterness threshold) was prepared, and compound (A) was added at a concentration of 1 ppt (below the flavor threshold). Twenty expert panelists evaluated the bitterness of the aqueous solution without compound (A) and the aqueous solution with 1 ppt of compound (A) added.

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

[0116] The bitterness was evaluated by presenting samples with and without compound (A) without knowing their contents, and asking participants to rate which was more bitter. As a result, all 20 participants rated the sample with 1 ppt of compound (A) added as more bitter.

[0117] (Example 2) Examination of compound (A) concentration In Example 1, the concentration of compound (A) was set to 0.1 ppt, and all other conditions were exactly the same as in Example 1, and a sensory evaluation was performed.

[0118] As a result, 17 out of 20 participants rated the sample with 0.1 ppt of compound (A) added 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 to water alone, adding 10 ppt did not impart bitterness or other flavors. However, when compound (A) was added to an aqueous solution of diketopiperazine (cycloprolylvaline), a bitter substance, adding 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 an aqueous solution of diketopiperazine The same evaluation as in Example 1 was performed for each of compounds (B) to (D). As a result, all 20 participants evaluated the samples with 1 ppt each of compounds (B) to (D) added as being more bitter than the samples without compounds (B) to (D).

[0121] (Example 4) Enhancement of bitterness with cycloprolylproline The effect of the bitterness enhancer of the present invention on cycloprolylproline, a diketopiperazine different from that used in Examples 1-3, was confirmed. A 1000 ppm aqueous solution of cycloprolylproline (Peptide Laboratories, Inc.) (approximately twice the bitterness threshold) was prepared, and compound (A) was added at a concentration of 1 ppt (below the flavor threshold). The bitterness of the aqueous solution without compound (A) and the aqueous solution with 1 ppt of compound (A) was evaluated by 20 expert panelists.

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

[0123] The bitterness was evaluated by presenting samples with and without compound (A) without knowing their contents, and asking participants to rate which was more bitter. As a result, all 20 participants rated the sample with 1 ppt of compound (A) added as more bitter.

[0124] (Example 5) Addition of the bitterness enhancer of the present invention to commercially available unsweetened black coffee. We prepared commercially available unsweetened black coffee, added 1 ppt of compound (A) to it, and had 20 expert panelists evaluate the bitterness of the commercially available unsweetened black coffee without compound (A) and the commercially available unsweetened black coffee with 1 ppt of compound (A) added.

[0125] The sensory evaluation method involved first tasting the aforementioned commercially available unsweetened black coffee (without compound (A) added) and discussing and describing five items (top aroma, roastiness, metallic, richness (richness, body), and bitterness (including astringency)). Using the additive-free commercially available unsweetened black coffee as a baseline, the sensory evaluation was performed on a scale of -1 point: slightly decreased, 0 points: no change at all, 1 point: slightly increased, 2 points: clearly increased, and 3 points: significantly increased. The average scores are shown in Table 2.

[0126] [Table 2]

[0127] As shown in Table 2, when compound (A) was added to commercially available unsweetened black coffee at a concentration of 1 ppt (below the flavor threshold in aqueous solution), it was found to enhance bitterness with almost no effect on the initial aroma, roasted flavor, metallic notes, or richness (body).

[0128] (Example 6) Preparation of a coffee flavor for enhancing bitterness containing compound (A) A coffee-like blended flavor composition was prepared using the following ingredients (parts by weight) as shown in Table 3 (Comparative Sample 1).

[0129] [Table 3]

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

[0131] (Example 7) Addition of the bitterness-enhancing coffee flavor of the present invention to unsweetened black coffee. 50g of roasted coffee beans (Colombia L value 22) were ground, then brewed with 90°C hot water to obtain 400g of extract, which was cooled to near room temperature. The Bx of the obtained extract was 2.9°. 0.6g of baking soda and 599.4g of water were added to make 1000g. This was divided into smaller portions, and either 0.1% of Comparative Product 1 or 0.1% of Product 1 of the present invention was added to each. After raising the temperature to 90°C, the portions were 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), using the unsweetened black coffee with Comparative Product 1 added as the baseline, with a score of -1 point: slightly reduced, 0 points: no change at all, 1 point: slightly increased, 2 points: clearly increased, and 3 points: significantly increased. The average scores are shown in Table 4.

[0132] [Table 4]

[0133] As shown in Table 4, unsweetened black coffee with the bitterness-enhancing coffee flavor of the present invention added was clearly more bitter than unsweetened black coffee with coffee flavor added without compound (A).

[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-category beer) was prepared, and compound (A) was added at a concentration of 1 ppt. Twenty expert panelists then evaluated the bitterness of the commercially available beer-flavored beverage (third-category beer) without compound (A) and the commercially available beer-flavored beverage (third-category beer) with 1 ppt of compound (A) added.

[0135] The sensory evaluation method involved first tasting the aforementioned commercially available beer-flavored beverage (third-category beer) (without compound (A) added) and discussing and describing six items (top aroma, floral notes, maltiness, body, and bitterness (including astringency)). Using the additive-free commercially available beer-flavored beverage (third-category beer) as a baseline, the sensory evaluation was performed on a scale of -1 point: slightly decreased, 0 points: no change at all, 1 point: slightly increased, 2 points: clearly increased, and 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 to commercially available beer-flavored beverages (third-category beer) at a concentration of 1 ppt (below the flavor threshold in aqueous solution), it was found to enhance bitterness and astringency with almost no effect on the initial aroma, floral notes, maltiness, or body.

[0138] (Example 9) Preparation of a beer flavor for enhancing bitterness containing compound (A) A beer-like blended flavor composition was prepared using the ingredients (parts by weight) listed in Table 6 below (Comparative Product 2).

[0139] [Table 6]

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

[0141] (Example 10) Addition of the bitterness-enhancing beer flavor of the present invention to a beer-flavored beverage. Non-alcoholic beer-flavored beverages were prepared according to the formulations shown in Table 7 below.

[0142] [Table 7]

[0143] Each non-alcoholic beer-flavored beverage was evaluated by 20 panelists based on its bitterness (including astringency), using the non-alcoholic beer-flavored beverage with comparison product 2 added as the baseline. The scoring was as follows: -1 point: slightly reduced, 0 points: no change at all, 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 clearly exhibited enhanced bitterness and astringency compared to the non-alcoholic beer-flavored beverage containing beer flavor without 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 (made from first flush tea leaves) was packed into a column, and steam distillation was performed by introducing 100°C steam from the bottom of the column. The steam containing the target substance obtained from the top of the column was condensed in a condenser (15°C to 20°C) to obtain 170 kg of distillate containing aroma components (170% by weight relative to the green tea leaves). 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 sodium chloride was added to 20 kg of the distillate and thoroughly dissolved before salting out. The green tea aroma after salting out was passed through 20 mL of synthetic adsorbent (Mitsubishi Chemical Corporation, product name "Sepabeads (registered trademark) SP-207") packed into a column at an outflow rate of 1 kg / h (SV = 50 h). -1 ), the fragrance components were adsorbed onto a synthetic adsorbent.

[0148] (c) Washing process Next, 200g of soft water was passed through the adsorbent containing the target substance at a rate of 1kg / h (SV=50h). -1 ). Subsequently, 20g each of 10 vol% ethanol aqueous solution, 25 vol% ethanol aqueous solution, 50 vol% ethanol aqueous solution, and 75 vol% ethanol aqueous solution were passed through the system at an outflow rate of 40g / h (SV=2h). -1 ), and cleaning was performed.

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

[0150] (Analysis of tea extracts) The quantitative analysis of 1-ethyl-2-(1-pyrrolylmethyl)pyrrole in 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 obtained fraction using a volumetric flask, filtering the samples through a membrane filter with a mesh size of 0.45 μm, and performing multiple reaction monitoring using LC-MS / MS (manufactured by AB Sciex Co., Ltd.). The m / z ratio was set from 175 to 80, and the results were compared with a standard sample obtained in advance by synthesis. The analytical conditions for LC-MS / MS were as follows. ≪LC-MS / MS analysis conditions≫ LC column: InertSustein C18 (3μm, 4.6×150mm) manufactured by GL Sciences Co., Ltd. Eluent A: Ultrapure water (0.1 vol% formic acid) Eluent B: Acetonitrile (0.1% formic acid by volume) (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% Furthermore, 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 measurements were performed using GC / MS (instrument name: GC7890A / MSD5975C, manufactured by Agilent Technologies, Inc.). The GC / MS analytical conditions were as follows. ≪GC / MS analysis conditions≫ GC column for GC / MS measurement: InertCap-WAX (long) manufactured by GL Sciences Co., Ltd. (Length 60m, inner diameter 0.25mm, liquid layer thickness 0.25μm) (GC conditions) Heating conditions: 40°C to 230°C, 5.0°C / min heating, 20 min hold. Column flow rate: 1.0 mL / min.

[0151] [Table 9]

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

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

[0154] (Example 12) Addition of the bitterness enhancer (natural extract) of the present invention to unsweetened black coffee. The unpasteurized coffee beverage concentrate used in Example 7 was divided into smaller portions, and either the unadditive-free version or the version with 0.1 ppm of Product 3 of the present invention added was prepared. After raising the temperature to 90°C, 190g of each was filled into cans and retort sterilized (121°C, 20 minutes, F=39) to obtain canned unsweetened black coffee. Each unsweetened black coffee was evaluated by 20 panelists on bitterness (including astringency), with the unadditive-free version as the baseline, using the following scale: -1 point: slightly reduced, 0 points: no change at all, 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, unsweetened black coffee with the bitterness enhancer (natural extract) of Product 3 of the present invention added was clearly more bitter than unsweetened black coffee without Product 3 of the present invention added.

[0157] (Example 13) Preparation of a beer flavor for enhancing bitterness containing the bitterness enhancer (natural extract) of the present invention. To comparative product 2 of Example 8 (see Table 6), product 3 of the present invention (see Example 10) was added at a concentration of 0.01% to product 4 of the present invention, which enhances bitterness in beer flavor.

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

[0159] [Table 11]

[0160] Each non-alcoholic beer-flavored beverage was evaluated by 20 panelists based on its bitterness (including astringency), using the non-alcoholic beer-flavored beverage with comparison product 2 added as the baseline. The scoring was as follows: -1 point: slightly reduced, 0 points: no change at all, 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 with the bitterness-enhancing beer flavor of the present invention added had a clearly enhanced bitterness compared to the non-alcoholic beer-flavored beverage with beer flavor added but without the present invention added.

Claims

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

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

3. The bitterness 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 grain tea.

4. A method for enhancing the bitterness of food and beverages, comprising the step of adding a bitterness-enhancing agent according to any one of claims 1 to 3 to food and beverages.

5. A flavor-imparting composition for enhancing bitterness, comprising the bitterness-enhancing agent described in any one of claims 1 to 3.

6. A method for enhancing the bitterness of food and beverages, comprising the step of adding the bitterness-enhancing flavor-imparting composition described in claim 5 to food and beverages.

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