Beverages containing citral

Abstract

To provide a new technology for suppressing off-flavors in beverages containing citral. [Solution] Use pyrroloquinoline quinone or a salt thereof.

Description

Technical Field

[0001] The present invention relates to a beverage containing citral and pyrroloquinoline quinone or a salt thereof, and related methods.

Background Art

[0002] Citrus fruits such as lemons contain many components, and a plurality of components such as citral among them bring the unique fragrance or taste of citrus fruits. Citral is used in applications such as fragrances.

[0003] And as described in Patent Document 1, in an aqueous solution such as a beverage or perfume, citral decreases by heating or over time during distribution and storage, and is converted into cyclized products such as p-menthadien-8-ols, and then it is known that deterioration odor causing substances such as p-methylacetophenone and p-cresol are generated. In particular, it has been found that the decrease of citral proceeds rapidly under low pH conditions (for example, pH 4.0 or less) such as acidic beverages.

[0004] In order to suppress the generation of such deterioration odor causing substances, various substances have been used. For example, in Patent Document 1, theaflavins, which are a kind of polyphenols contained in black tea, are used for the suppression.

[0005] On the other hand, pyrrolopyroloquinoline quinone is also denoted as PQQ and is used in various fields such as beverages. For example, in Patent Document 2, PQQ is used to impart a fruity flavor to a non-alcoholic beer-taste beverage.

[0006] Furthermore, Patent Document 1 discloses that even when epigallocatechin gallate, a polyphenol known to exhibit particularly strong antioxidant activity, was added at a high concentration (60 ppm) to a citral-containing acidic aqueous solution, the formation of p-cresol was not suppressed at all. Patent Document 1 also shows that L-ascorbic acid (vitamin C), commonly used as an antioxidant, does not suppress the formation of p-cresol at a concentration of 5 ppm. In other words, it is difficult to infer the presence or absence of an effect on suppressing the formation of citral-derived odor-causing substances, or the strength of that effect (the concentration required for the effect to manifest), from the strength of the antioxidant activity of a substance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2005-171116 [Patent Document 2] Japanese Patent Publication No. 2019-076045 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] As mentioned above, while technologies exist to suppress off-flavors in beverages containing citral, if the amount of food ingredients or food additives added for this purpose is large, it may have an impact on the flavor and appearance of the beverage, as well as on the cost of transporting the ingredients, and these issues may not always be satisfactory.

[0009] The object of this invention is to provide a new technology for suppressing off-flavors in beverages containing citral. [Means for solving the problem]

[0010] The inventors of the present invention have discovered that PQQ can strongly suppress the generation of off-flavors in beverages containing citral, and have completed the present invention. The present invention relates to, but is not limited to, the following. 1. A beverage containing citral and pyrroloquinoline quinone or its salt at a concentration of 5 ppb or more. 2. The beverage described in paragraph 1, wherein the pyrroloquinoline quinone or salt thereof contains 5 to 1000 ppb. 3. The beverage described in item 1, having a citral content of 0.01 to 30 ppm. 4. An alcoholic beverage as described in any one of items 1 to 3. 5. A non-alcoholic beverage as described in any one of items 1 to 3. 6. A beverage described in any one of items 1 to 3, having a pH of 4.0 or less. 7. A method for suppressing the off-flavor of a beverage containing citral, comprising mixing raw materials such that the beverage contains 5 ppb or more of pyrroloquinoline quinone or a salt thereof. 8. An agent containing pyrroloquinoline quinone or a salt thereof, which suppresses the deterioration of beverages containing citral. [Effects of the Invention]

[0011] The present invention can strongly suppress off-flavors in beverages containing citral. Specifically, the PQQ used in the present invention has a stronger off-flavor suppression effect at lower concentrations than the conventionally known theaflavins.

[0012] Furthermore, the present invention also yields a unique citral degradation product profile. To explain this point, several substances that cause degradation odors are known to be produced by the degradation of citral, including not only p-methylacetophenone and p-cresol, but also α,p-dimethylstyrene. When α,p-dimethylstyrene is produced, its hydrated molecule, p-cymen-8-ol, is also produced, but the risk of p-cymen-8-ol exhibiting a degradation odor is low. Specifically, it has been reported that the odor threshold (concentration) of p-cymen-8-ol is more than 250 times higher than that of α,p-dimethylstyrene (Hisao Ueno, Doctoral Dissertation, "Food Chemical and Food Functional Studies on the Use of Plant Polyphenols," 2015). The present invention preferentially generates p-cymen-8-ol, which has only a weak degradation odor, over α,p-dimethylstyrene, which has a strong degradation odor. In other words, it reduces the α,p-dimethylstyrene / p-cymen-8-ol production ratio, and as a result, the degradation odor can be suppressed more efficiently. [Modes for carrying out the invention]

[0013] The beverage and related methods of the present invention are described below. Unless otherwise specified, "ppm" and "ppb" as used herein refer to ppm and ppb in weight / volume (w / v), respectively, and are synonymous with "mg / L" and "μg / L".

[0014] Furthermore, the term "alcohol" as used in this specification means ethanol unless otherwise specified. (Citral) The beverage of the present invention contains citral. Citral (also known as 3,7-dimethylocta-2,6-dienal, chemical formula: C) 10 H 16Citral (O) is a monoterpene having an aldehyde group. It includes the trans isomer geranial and the cis isomer neral. Citral is a component found in citrus fruits and has a lemon-like aroma, and it produces an off-flavor. The citral content in the beverage of the present invention is preferably 0.01 to 30 ppm, more preferably 0.1 to 20 ppm. The citral content specified herein refers to the total amount of the two isomers, but the beverage of the present invention does not need to contain both geranial and neral. That is, the beverage of the present invention contains geranial, neral, or both.

[0015] The citral content in the beverage of the present invention may be measured at any point in time by any known method, for example, by high-performance liquid chromatography (HPLC) or gas chromatography / mass spectrometry (GC-MS). Furthermore, even if the components deteriorate and citral decomposes during distribution and storage after beverage production, it is possible to estimate the citral content at the time of beverage production by utilizing the content of initial citral-derived cyclization products such as p-mentadiene-8-ols and p-menth-2-ene-1,8-diol. Therefore, even if the citral content is below the limit of quantification when the beverage is analyzed at any point after distribution, it is possible to estimate the citral concentration at the time of beverage production.

[0016] In the present invention, the source of citral is not particularly limited, but for example, at least one selected from the group consisting of citrus fruits, citrus peels, citrus juices, and processed products thereof, as well as citrus flavorings, can be used. If such a source is used, the beverage of the present invention contains at least one selected from the above group.

[0017] Examples of citrus fruits related to the fruit, peel, and juice include oranges, unshu mikan, grapefruit, lemons, limes, pummelos, iyokan, natsumikan, sudachi, hassaku, ponkan, shikuwasa, and kabosu. Preferred citrus fruits are oranges, lemons, grapefruit, and limes. Any one of these may be used alone, or two or more of them may be used in combination. For example, orange juice and lemon juice may be used, or orange peel and lemon juice may be used.

[0018] In this specification, "juice" means the juice obtained from fruits, and it may be in any form, either straight juice obtained by juicing fruits and used as it is, or concentrated juice obtained by concentrating straight juice. Also, clear juice or cloudy juice can be used, and whole fruit juice obtained by crushing the whole fruit including the outer skin of the fruit and removing only particularly coarse solids such as seeds, fruit puree obtained by straining the fruit, or juice obtained by crushing or extracting the pulp of dried fruits can also be used.

[0019] When the beverage of the present invention contains citrus fruit juice, the content of the juice is not particularly limited. For example, it is 0 to 30 w / w% or 0 to 20 w / w% in terms of the juice ratio. Note that for confirmation, the content of the juice in this specification means the total amount. Therefore, when the beverage contains only one type of citrus fruit juice, the content of the citrus fruit juice in the beverage of the present invention means the content of only that juice, and when the beverage contains multiple types of citrus fruit juice, the content means the total amount of those juices.

[0020] In the present invention, the "juice ratio" in the beverage is calculated by the following conversion formula using the amount of juice blend (g) blended in 100 mL of the beverage. Also, when calculating the concentration ratio, it shall conform to the JAS standard, and the refractive index readings of sugars such as carbohydrates and honey added to the juice shall be excluded.

[0021] Juice ratio (w / w%) = <amount of juice blend (g)> × <concentration ratio> / 100 mL / <density of the beverage> × 100 The beverage of the present invention may contain, or may not contain, citrus raw materials, i.e., fruits, peels, and / or juices, as well as non-citrus plant raw materials, i.e., fruits, peels, and / or juices of plants other than citrus. The types of such non-citrus plant raw materials are not particularly limited, but include apples, grapes, peaches, tropical fruits (pineapple, guava, banana, mango, acerola, lychee, papaya, passion fruit, etc.), plums, pears, apricots, Japanese apricots, berries, kiwifruit, strawberries, and melons. These may be used individually or in combination of two or more. With regard to fruit juice, the total content of fruit juice, including citrus fruit juice, in the beverage of the present invention is not particularly limited, but for example, it is 30 w / w% or less, or 20 w / w% or less, when converted to a fruit juice percentage. In some embodiments, the beverage of the present invention does not contain fruit juices of non-citrus plants.

[0022] Processed products obtained from citrus fruits, citrus peels, and / or citrus juices are not particularly limited, but examples include macerated liquor of the fruit or peel and freeze-dried macerated liquor. The former is obtained by macerating the fruit and / or peel in an alcohol-containing solution for a certain period of time and removing insoluble matter as necessary from the resulting maceration solution. The latter is obtained by freezing the fruit and / or peel, pulverizing the resulting frozen material, macerating the resulting pulverized material in an alcohol-containing solution for a certain period of time, and removing insoluble matter as necessary from the resulting maceration solution. A specific method for producing freeze-dried macerated liquor is described, for example, in WO2006 / 009252.

[0023] In the present invention, "citrus flavoring" means a flavoring that contains aromatic components found in citrus fruits, or a flavoring that has the scent of citrus fruits, and includes natural flavorings, food extracts, and synthetic flavorings. The examples of citrus fruits and preferred citrus fruits described above also apply to citrus flavorings. Furthermore, the beverage of the present invention may contain one type of citrus flavoring, or it may contain two or more types of citrus flavorings.

[0024] If the beverage of the present invention contains a citrus flavoring, the amount of the flavoring is not particularly limited, but for example, it may be 0 to 10,000 ppm or 10 to 3,000 ppm. For clarification, this amount refers to the total amount.

[0025] The citrus flavoring content in the beverage of the present invention may be measured at any point in time by any known method, for example, by high-performance liquid chromatography (HPLC) or gas chromatography-mass spectrometry (GC-MS).

[0026] (Pyrroloquinoline quinone) The beverage of the present invention contains pyrroloquinoline quinone (PQQ, chemical formula: C 14 It contains H6N2O8, its salt, or both.

[0027] The PQQ or its salt content in the beverage of the present invention is 5 ppb or more, preferably 5 to 1000 ppb, more preferably 10 to 1000 ppb, more preferably 10 to 100 ppb, and more preferably 50 to 100 ppb. To clarify, this content refers to the total amount of PQQ and its salt in the beverage.

[0028] A low content of PQQ or its salts results in a reduced odor suppression effect, while a high content tends to intensify undesirable flavors in the beverage. Any known method may be used to measure the PQQ or its salt content in beverages, for example, by high-performance liquid chromatography (HPLC) or liquid chromatography-mass spectrometry (LC / MS).

[0029] Examples of salts of PQQ include alkali metal salts, e.g., lithium salts, sodium salts, potassium salts; alkaline earth metal salts, e.g., magnesium salts, calcium salts; transition metal salts, e.g., zinc salts, iron salts, cobalt salts, copper salts; aluminum salts; organic amine salts, e.g., choline salts, ethanolamine salts, triethanolamine salts, trimethylamine salts, triethylamine salts, dicyclohexylamine salts, dibenzylamine salts, phenethylbenzylamine salts, procaine salts, morpholine salts, pyridine salts, piperidine salts, piperazine salts, N-ethylpiperidine salts; ammonium salts; and basic amino acid salts, e.g., lysine salts, arginine salts. Preferred salts are sodium salts and potassium salts.

[0030] For confirmation, the scope of PQQ and its salts as used herein also includes hydrates such as salt hydrates. For example, sodium salts such as pyrroloquinoline quinone disodium can form trihydrates and pentahydrates, which are also included in the salts of PQQ as used herein.

[0031] (alcohol) The beverage of the present invention may or may not contain alcohol. If the beverage of the present invention contains alcohol, that is, if it is an alcoholic beverage, the alcohol content of the beverage is, for example, 1 to 50 v / v% or 1 to 10 v / v%.

[0032] In this specification, the alcohol content in a beverage can be measured by any known method, but for example, it can be measured by a vibrating densimeter. Specifically, a sample is prepared by removing carbon dioxide from the beverage as needed by filtration or ultrasound, and the sample is then steam distilled. The density of the resulting distillate at 15°C is measured, and the alcohol content can be calculated by converting it using "Table 2 Conversion Table for Alcohol Content, Density (15°C) and Specific Gravity (15 / 15°C)," which is an appendix to the National Tax Agency's prescribed analytical method (National Tax Agency Instruction No. 6 of 2007, revised June 22, 2007).

[0033] If the alcohol content is low, other analytical methods such as gas chromatography may be used. If the beverage of the present invention is an alcoholic beverage, alcohol may be incorporated into the beverage by any means, but typically, the beverage contains an alcohol raw material, thereby containing 1 v / v% or more of alcohol. There are no particular limitations on the alcohol raw material, but examples include spirits (rum, vodka, gin, tequila, etc.), liqueurs, whiskey, brandy, or shochu, and may also be sparkling alcoholic beverages such as beer or low-malt beer, or brewed alcoholic beverages such as sake or fruit wine. Preferably, the alcohol raw material is whiskey, brandy, or neutral spirits. These alcohol raw materials can be used individually or in combination.

[0034] When the present invention relates to an alcoholic beverage, the type is not particularly limited, but is preferably a chuhai (in relation to the present invention, meaning an alcoholic carbonated beverage made by diluting distilled spirits with another beverage such as water, juice, or tea) or its concentrate, a cocktail (in relation to the present invention, meaning a beverage containing spirits or liqueurs, acidic fruit juice such as citrus fruits, a sweetener, and carbonation if necessary), or a sour (in relation to the present invention, meaning a beverage containing spirits, acidic fruit juice such as citrus fruits, a sweetener, and carbonation).

[0035] The present invention may also include non-alcoholic beverages, that is, beverages with an alcohol content of less than 1 v / v%. The type is not particularly limited, but an example is an alcohol-flavored beverage that has a taste similar to an alcoholic beverage. Examples of alcohol-flavored beverages include, but are not limited to, beer-flavored beverages, chuhai-flavored beverages, non-alcoholic cocktails, sour-flavored beverages, wine-flavored beverages, and sake-flavored beverages. To explain in more detail using chuhai-flavored beverages, non-alcoholic cocktails, and sour-flavored beverages as examples, these beverages refer to beverages that, while being non-alcoholic, achieve a taste similar to the modeled chuhai, cocktail, and sour, respectively. Another example of a non-alcoholic beverage of the present invention is a soft drink. Examples of soft drinks include, but are not limited to, carbonated beverages (including flavored water), fruit juices, fruit and vegetable beverages, dairy beverages, and lactic acid bacteria beverages.

[0036] (pH) In one embodiment, the pH of the alcoholic beverage according to the present invention is 4.0 or less, preferably 2.3 to 4.0, more preferably 2.8 to 3.8, and even more preferably 3.0 to 3.5. When adjusting the pH of the beverage, the method of adjustment is not particularly limited, and it can be adjusted using substances commonly used for adjusting the pH of beverages, such as citric acid or trisodium citrate, or the pH can be adjusted by adjusting the content of other components (e.g., fruit juice).

[0037] Since citral is prone to degradation at low pH levels, the present invention is particularly suitable for beverages within the above pH range. (Carbon dioxide) The beverage of the present invention may contain carbon dioxide. Carbon dioxide can be added to the beverage by methods commonly known to those skilled in the art, for example, but not limited to these, by dissolving carbon dioxide in the beverage under pressure, mixing carbon dioxide and the beverage in a pipe using a mixer such as a carbonator from Zuhenhagen, or by spraying the beverage into a tank filled with carbon dioxide to allow the beverage to absorb the carbon dioxide, or by mixing the beverage with carbonated water. The carbon dioxide pressure is adjusted using these means as appropriate.

[0038] If the beverage of the present invention contains carbon dioxide, the carbon dioxide pressure is not particularly limited, but is preferably 0.7 to 4.5 kgf / cm². 2 , more preferably 0.8~2.8 kgf / cm² 2 In this invention, the carbon dioxide pressure can be measured using the GVA-500A gas volume measuring device manufactured by Kyoto Electronics Manufacturing Co., Ltd. For example, the sample temperature is set to 20°C, and after degassing (snifting) and shaking the air inside the container using the gas volume measuring device, the carbon dioxide pressure is measured. In this specification, unless otherwise specified, carbon dioxide pressure refers to the carbon dioxide pressure at 20°C.

[0039] (Other ingredients) In addition to the effects of the present invention, the beverage may also contain additives commonly used in beverages, such as flavorings, vitamins, pigments, antioxidants, preservatives, colorants, seasonings, extracts, pH adjusters, citric acid, and quality stabilizers, as long as they do not impair the effects of the present invention.

[0040] (Packaged beverages) The beverage of the present invention can be provided in a containerized form. Container forms include, but are not limited to, metal containers such as cans, PET bottles, paper cartons, glass bottles, and pouches. For example, a sterilized containerized product can be produced by a method of heat sterilization, such as retort sterilization, after filling the beverage of the present invention into a container, or by a method of sterilizing the beverage and then filling it into a container.

[0041] (Related methods) In one aspect, the present invention is a method for producing a beverage containing citral and 5 ppb or more of pyrroloquinoline quinone or a salt thereof. The method comprises mixing raw materials so that the beverage contains 5 ppb or more of pyrroloquinoline quinone or a salt thereof. The method may further comprise mixing the raw materials so that the beverage contains citral.

[0042] Since this manufacturing method can also suppress the off-flavor of beverages containing citral, in another respect, this method is a method for suppressing the off-flavor of beverages containing citral. Examples of the aforementioned raw materials include citral or raw materials containing it, pyrroloquinoline quinone or raw materials containing it, water, and alcohol.

[0043] The types of components in the beverage, their content, pH, carbon dioxide pressure, and preferred ranges thereof, as well as the method of adjusting them, are as described above with respect to the beverage of the present invention or are obvious from thereto. The timing is also not limited.

[0044] (An agent that suppresses the odor of deterioration) In one aspect, the present invention is an anti-odor agent for citral-containing beverages, containing pyrroloquinoline quinone or a salt thereof. The content of pyrroloquinoline quinone or a salt thereof in the anti-odor agent is not limited as long as the anti-odor effect is exerted. On the other hand, the content of pyrroloquinoline quinone or a salt thereof in the beverage is preferably 5 ppb or more. A more preferred range of this content is as described above with respect to the beverage.

[0045] The form of the inhibitor is not particularly limited, but may be a fragrance or a seasoning. (Numerical range) For clarity, numerical ranges in this specification include their endpoints, i.e., the lower and upper limits. [Examples]

[0046] The present invention will be described in more detail below with reference to specific experimental examples, but the present invention is not limited to the experimental examples described below. (Test Example 1) Effects of PQQ and theaflavins on the generation of citral-derived off-odor components A standard solution was prepared using citral, ethanol, water, citric acid, and trisodium citrate, with a pH of 3.4, an alcohol content of 5 v / v%, and an initial citral concentration of 5 ppm (citric acid concentration: 10 mM). The citral was supplied by "Citral" (Tronto Research Chemicals).

[0047] A portion of the standard solution was taken and used as a control sample. Next, another portion of the standard solution was divided into several parts, and several samples were prepared by adding pyrroloquinoline quinone (PQQ) salt or theaflavin, which are materials that suppress deterioration odor, at various concentrations. The source of the PQQ salt was pyrroloquinoline quinone disodium (Fujifilm Wako Pure Chemical Industries, Ltd., hereinafter sometimes referred to as "PQQ salt" or simply "PQQ"), and the source of theaflavin was Theaflavin (Fujifilm Wako Pure Chemical Industries, Ltd.). The content of PQQ salt or theaflavin in each sample is shown in the table below.

[0048] Next, the control sample and the sample described above were stored in glass vials (Mighty Vials, Maruemu Co., Ltd.) at 55°C for 5 days under light-shielding conditions to allow them to deteriorate. Then, the concentrations of p-cresol, p-methylacetophenone, and α,p-dimethylstyrene, which are the substances causing the deterioration odor, and p-cymen-8-ol, a deterioration product, in the sample were measured by HPLC, along with known concentration solutions of each substance. Since the amount of p-cresol in the sample was trace, the sample was concentrated by solid-phase extraction before measurement. Specifically, 20 ml of the sample was added to a polymer reverse-phase packing material (Oasis HLB Plus Short Cartridge (packing material amount: 225 mg, Particle Size: 60 μm), Waters), and the p-cresol contained in the sample was adsorbed onto the packing material. Then, 4 ml of ethanol was passed through the packing material using a syringe to desorb the p-cresol, and the resulting eluate was subjected to HPLC analysis.

[0049] The p-cresol and p-methylacetophenone content (amount produced) in each sample is shown in the table below as a relative amount (%) to the control sample. Furthermore, the weight ratio of α,p-dimethylstyrene content to p-cymen-8-ol content is shown in the table below in the "dimethylstyrene / p-cymen-8-ol" column.

[0050] [Table 1]

[0051] PQQ showed a stronger inhibitory effect on the formation of citral-derived off-odor components than theaflavins. For example, comparing samples 1-4 and 1-14, PQQ required only about 1 / 50th the concentration of theaflavin to show a similar level of suppression of the generation of degraded odor components. In other words, it can be said that PQQ is an ingredient that can suppress degraded odors with a small amount of formulation.

[0052] Furthermore, PQQ preferentially produced p-cymene-8-ol, which has a high odor threshold (concentration) and a low risk of exhibiting a degradation odor, over α,p-dimethylstyrene, a closely related substance that exhibits a strong degradation odor. In other words, PQQ reduced the α,p-dimethylstyrene / p-cymene-8-ol production ratio compared to theaflavin. From this perspective as well, it can be said that PQQ can suppress degradation odors more efficiently.

[0053] The conditions for the HPLC analysis described above are as follows: Equipment: Vanquish Binary Pump H (Thermo Fisher Scientific) Column: Unison UK-C18 HT 100×3mm (particle size 3μm) (Imtakt) Temperature: 40℃ Mobile phase: (A) Ultrapure water (for LC / MS (Fujifilm Wako Pure Chemical Industries, Ltd.)) (B) Acetonitrile (for LC / MS (Fujifilm Wako Pure Chemical Corporation)) Flow rate: 0.8 ml / min Gradient (%B): 0 min. 0% → 0.5 min. 0% → 4.5 min. 100% → 6.4 min. 100% → 6.5 min. 0% → 8 min. 0% Detection method: UV wavelength: 280nm (p-cresol), 254nm (p-methylacetophenone), 240nm (α,p-dimethylstyrene), 200nm (p-cymen-8-ol) Injection volume: 5μl (Test Example 2) Effect of PQQ on the degradation of citral at high initial concentrations The experiment was conducted using the same method as in Test Example 1, except that the initial concentrations of the PQQ salt and citral were changed. The alcohol content was 5 v / v%.

[0054] A sample without PQQ salt was used as a control sample, and both the control sample and each sample were stored at 55°C for 5 days under light-shielding conditions to allow them to degrade. After degradation, the relative concentrations of p-cresol and p-methylacetophenone in each sample relative to the control sample were measured. The initial citral concentration and the concentration of PQQ salt used in each sample, along with the measurement results after degradation, are shown below.

[0055] [Table 2]

[0056] Even when the initial citral concentration was high, PQQ suppressed the generation of substances that cause off-odors. (Test Example 3) Effect of Ethanol Content The experiment was conducted using the same method as in Test Example 1, except that the ethanol content was changed to 0.8 v / v%. The initial concentration of citral was 5 ppm. However, only concentrations of 10 ppb and 50 ppb of the PQQ salt were used.

[0057] A sample without PQQ salt was used as a control sample, and both the control sample and each sample were stored at 55°C for 5 days under light-shielding conditions to allow them to degrade. After degradation, the relative concentrations of p-cresol and p-methylacetophenone in each sample relative to the control sample were measured. The concentrations of PQQ salt used in each sample and the measurement results after degradation are shown below.

[0058] [Table 3]

[0059] Even when the ethanol content was changed to less than 1%, the same trend as in Test Example 1 was observed. (Test Example 4) Effect of PPQ on taste In the same manner as in Test Example 1, a standard solution was prepared using citral, ethanol, water, citric acid, and trisodium citrate, with a pH of 3.4, an alcohol content of 5 v / v%, and an initial citral concentration of 5 ppm (citric acid concentration: 10 mM). This standard solution was used as a control sample. Subsequently, several samples were prepared by adding PQQ salt, a material that suppresses deterioration odor, to the standard solution at various concentrations.

[0060] The obtained control samples and each individual sample were subjected to sensory evaluation by three evaluators according to the following criteria, without allowing them to deteriorate. Subsequently, the evaluators discussed the results of the sensory evaluation among themselves and made a final decision on the evaluation.

[0061] standard ◎: No difference in taste compared to the control. ○: Although there are differences in taste compared to the control, it is within an acceptable range for drinking.

[0062] △: A difference in taste quality was observed compared to the control, making it unsuitable for consumption. The concentrations of PQQ salt used in each sample and the evaluation results are shown below.

[0063] [Table 4]

[0064] As the concentration of PQQ increased, the artificial taste (grittiness) of the beverage tended to become stronger. However, if the concentration of PQQ was below a certain level, the taste was perfectly acceptable for drinking.

Claims

1. A beverage containing citral and pyrroloquinoline quinone or its salt at a concentration of 5 ppb or higher.

2. The beverage according to claim 1, wherein the pyrroloquinoline quinone or salt thereof contains 5 to 1000 ppb.

3. The beverage according to claim 1, wherein the citral content is 0.01 to 30 ppm.

4. A beverage according to any one of claims 1 to 3, which is an alcoholic beverage.

5. A non-alcoholic beverage according to any one of claims 1 to 3.

6. A beverage according to any one of claims 1 to 3, wherein the pH is 4.0 or less.

7. A method for suppressing the off-flavor of a beverage containing citral, comprising mixing raw materials such that the beverage contains 5 ppb or more of pyrroloquinoline quinone or a salt thereof.

8. An agent containing pyrroloquinoline quinone or a salt thereof, which suppresses the deterioration of beverage odors in citral-containing beverages.

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