阅读说明：本技术 微生物增殖抑制剂、微生物污染防止方法及饮料 (Microorganism proliferation inhibitor, method for preventing microorganism contamination, and beverage ) 是由 富贵泽伸哉 野中裕司 若林贤一 山下麻衣 于 2019-08-05 设计创作，主要内容包括：本发明的目的在于提供一种以对热稳定,对于各种微生物具有抗菌作用的物质为有效成分的微生物增殖抑制剂、微生物污染防止方法及饮料。本发明涉及含有异黄腐酚(Isoxanthohumol)作为有效成分的微生物增殖抑制剂、使用其的微生物污染防止方法及饮料。(The purpose of the present invention is to provide a microbial growth inhibitor containing a substance that is stable to heat and has an antibacterial effect against various microorganisms as an active ingredient, a method for preventing microbial contamination, and a beverage. The present invention relates to a microbial growth inhibitor containing Isoxanthohumol (Isoxanthohumol) as an active ingredient, a method for preventing microbial contamination using the same, and a beverage.)

1. A microorganism proliferation inhibitor characterized by containing isoxanthohumol as an active ingredient.

2. The microbial proliferation inhibitor according to claim 1, which is for a beverage.

3. The microbial growth inhibitor according to claim 1 or 2, wherein the microorganism is at least one bacterium selected from the group consisting of alicyclobacillus bacteria, bacillus bacteria, clostridium bacteria, and staphylococcus bacteria.

4. The microbial proliferation inhibitor according to any one of claims 1 to 3, wherein the microorganism is at least one selected from the group consisting of Alicyclobacillus acidoterrestris, Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus.

5. A method for preventing microbial contamination of a beverage, characterized by adding isoxanthohumol so as to reach 25 ppm by mass or more.

6. The method according to claim 5, wherein the isoxanthohumol is added in an amount of 50 ppm by mass or more.

7. The method for preventing microbial contamination according to claim 5 or 6, wherein the pH of the beverage is adjusted to 4.6 or less.

8. The method according to any one of claims 5 to 7, wherein the microorganism is at least one bacterium selected from the group consisting of Alicyclobacillus bacteria, Bacillus bacteria, Clostridium bacteria, and Staphylococcus bacteria.

9. The method according to any one of claims 5 to 8, wherein the microorganism is at least one selected from the group consisting of Alicyclobacillus acidoterrestris, Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus.

10. A beverage characterized by containing isoxanthohumol in a range of more than 50 ppm by mass and not more than 180 ppm by mass and having a pH of not more than 4.6.

11. The beverage according to claim 10, characterized by containing not less than 60 mass ppm of isoxanthohumol.

12. The beverage according to claim 10 or 11, wherein the beverage is an alcoholic beverage, a nonalcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, or a fruit-and vegetable-based beverage.

13. The beverage according to any one of claims 10 to 12, wherein the beverage is a nonalcoholic beer-flavored beverage, a functional beverage, a carbonated beverage, or a fruit-and vegetable-based beverage.

Technical Field

The present invention relates to a microbial proliferation inhibitor containing Isoxanthohumol (Isoxanthohumol), a method for preventing microbial contamination using Isoxanthohumol, and a beverage.

Background

In commercial beverages, it is important to prevent microbial contamination such as yeast, Bacteria (Bacteria), and mold and to improve the storage stability. Typical methods for preventing microbial contamination include reducing the pH to acidic, reducing the water activity by drying or the like, performing heat treatment, storing at low temperature, adding a preservative, aseptic packaging, nitrogen-filled packaging, and the like. The method of sterilizing a beverage and its resistance to sterilization can be influenced by the nature of the beverage, such as the components contained (e.g., sugar, fruit juice, alcohol, vitamins, or micronutrients), carbonic acid, water quality, and pH, and the type of microorganism to be sterilized. Therefore, active studies are being conducted on the search for natural ingredients that have antibacterial effects against various microorganisms and are safe.

Xanthohumol is known as a component contained in hop (scientific name: Humulus lupulus) of a plant of the Cannabaceae family used as a raw material of beer. Xanthohumol is represented by the molecular formula C₂₁H₂₂O₅One of the polyphenols represented, in particular among those classified as "prenylchalcone". As the physiological activity of xanthohumol, carcinogenic inhibitory action, anti-inflammatory action, anti-obesity action, bone resorption inhibitory action, antibacterial action, and the like have been reported.

For example, patent document 1 describes a preservative for food containing xanthohumol as an active ingredient, which is a hop component, and discloses that xanthohumol has an antibacterial effect against a specific spoilage bacterium (e.g., Bacillus subtilis). However, it is not clear whether or not other putrefying bacteria have an antibacterial action, and nothing is disclosed about the antibacterial action against acidophilic thermophilic bacteria.

Xanthohumol is irreversibly structurally transformed into isoxanthohumol by heating. It is reported that, especially in the production of beer, most of it is converted to isoxanthohumol.

It has been reported that, although both xanthohumol and isoxanthohumol have isoprenyl groups, the former contains a chalcone skeleton as a partial structure and the latter contains a flavanone skeleton as a partial structure, and exhibit physicochemical properties and physiological activities different from each other. Patent document 2 describes that xanthohumol is very effective in anticancer action, but isoxanthohumol is very weak in anticancer action. Therefore, it is difficult to analogize the physiological activity of isoxanthohumol based on information related to the physiological activity of xanthohumol.

Patent document

Patent document 1: japanese patent No. 4374123

Patent document 2: japanese laid-open patent publication No. 2007-289185

Disclosure of Invention

Patent document 1 reports that xanthohumol exhibits an antibacterial effect on food products. However, it has not been reported that isoxanthohumol produced as a result of irreversible structural transformation of xanthohumol with heating exhibits such an antibacterial effect.

In addition, for example, in the production of beverages, heating under sterilization conditions by the japanese food sanitation act is required, and therefore, a substance having thermal stability and contributing to an antibacterial effect of foods and drinks has been desired.

The purpose of the present invention is to provide a microbial growth inhibitor containing a substance that is stable to heat and has an antibacterial effect against various microorganisms as an active ingredient, a method for preventing microbial contamination, and a beverage.

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found for the first time that isoxanthohumol exhibits an antibacterial action against various microorganisms. Further, isoxanthohumol is excellent in beverage suitability as compared with xanthohumol because of its heat resistance, and is expected to be applicable to beverages and the like, and the present invention has been completed.

Isoxanthohumol is a substance contained in a trace amount in hops (Humulus lupulus L), exhibits an antibacterial effect, and is excellent in beverage suitability. Therefore, by blending isoxanthohumol, it is possible to develop a beverage or the like having high safety and high storage stability.

That is, the present invention relates to the following microbial growth inhibitor, a method for preventing microbial contamination of a beverage, and a beverage.

[1] A microorganism proliferation inhibitor characterized by containing isoxanthohumol as an active ingredient.

[2] The microbial growth inhibitor according to the above [1], which is for beverages.

[3] The microbial growth inhibitor according to the above [1] or [2], wherein the microorganism is at least one bacterium selected from the group consisting of Alicyclobacillus bacteria, Bacillus bacteria, Clostridium bacteria and Staphylococcus bacteria.

[4] The microbial growth inhibitor according to any one of the above [1] to [3], wherein the microorganism is at least one selected from the group consisting of Alicyclobacillus acidoterrestris, Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus.

[5] A method for preventing microbial contamination of a beverage, characterized by adding isoxanthohumol so as to reach 25 ppm by mass or more.

[6] The method for preventing microbial contamination according to the above [5], wherein isoxanthohumol is added so as to be 50 ppm by mass or more.

[7] The method for preventing microbial contamination according to the above [5] or [6], wherein the pH of the beverage is adjusted to 4.6 or less.

[8] The method for preventing microbial contamination according to any one of the above [5] to [7], wherein the microorganism is at least one bacterium selected from the group consisting of bacteria of the genus Alicyclobacillus, bacteria of the genus Bacillus, bacteria of the genus Clostridium, and bacteria of the genus Staphylococcus.

[9] The method for preventing microbial contamination according to any one of the above [5] to [8], wherein the microorganism is at least one selected from the group consisting of Alicyclobacillus acidoterrestris, Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus.

[10] A beverage characterized by containing isoxanthohumol in a range of more than 50 ppm by mass and not more than 180 ppm by mass and having a pH of not more than 4.6.

[11] The beverage according to the above [10], characterized by containing not less than 60 mass ppm of isoxanthohumol.

[12] The beverage according to the above [10] or [11], wherein the beverage is an alcoholic beverage, a nonalcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, or a fruit-and vegetable-based beverage.

[13] The beverage according to any one of the above [10] to [12], which is a nonalcoholic beer-flavored beverage, a functional beverage, a carbonated beverage, or a fruit-and vegetable-based beverage.

According to the present invention, a microorganism growth inhibitor, a method for preventing microbial contamination, and a beverage containing a substance which is stable to heat and has an antibacterial effect against various microorganisms as an active ingredient can be provided.

Detailed Description

The microbial proliferation inhibitor of the present invention contains isoxanthohumol as an active ingredient.

Isoxanthohumol is stable to heat and exhibits antibacterial action. Therefore, even when the microorganism growth inhibitor is blended into a beverage that requires heating under sterilization conditions according to the japanese food sanitation act during production, the microorganism growth inhibitor exhibits a growth inhibitory effect, and thus the microorganism growth inhibitor of the present invention is suitably used for foods and beverages that require heating in the production process. Is particularly suitable for beverages.

Thus, the microorganism growth inhibitor of the present invention is preferably for beverages.

Isoxanthohumol can be produced from, for example, a hop (Humulus lupulus) extract by a process such as heating. By heating the hop extract, isoxanthohumol can be formed in the extract. The hop extract can be obtained by extracting hop pellets with a solvent, and can be prepared by a process related to purification, if necessary, or by a known method for preparing a hop extract. Examples of the extraction method include an extraction method using an ethanol solvent, which is used as a method for producing a hop extract used in beer brewing. Hop extracts are commercially available, and commercially available hop extracts may also be used. The heating of the hop extract to produce isoxanthohumol is preferably carried out at 80 to 140 ℃ (more preferably at 85 to 100 ℃) for 15 minutes to 5 hours (more preferably 20 minutes to 3 hours). The purification of the hop extract for the preparation of isoxanthohumol is carried out in a known manner. Examples of the purification method include a method using HPLC, an adsorption column, or the like, or a method using precipitation due to a change in solubility. In addition, isoxanthohumol can be produced by heating xanthohumol. The heating temperature in this case is preferably 80 to 140 ℃ (more preferably 85 to 100 ℃) for 15 minutes to 5 hours (more preferably 20 minutes to 3 hours).

Isoxanthohumol, for example, is reported to be stable at high temperature conditions of 100 ℃. In the food sanitation act of japan, sterilization conditions are defined as standards for refreshing beverages such as water, and for example, a substance having a ph of 4.0 or more (excluding a substance having a ph of 4.6 or more and a water activity of more than 0.94) needs to be heated at 85 ℃ for 30 minutes. In such a sterilization step, isoxanthohumol can be stably contained in the beverage, and therefore, it is advantageous in that it can be easily blended in the beverage. Thus, according to the present invention, it is possible to provide a beverage using a microorganism proliferation inhibitor which is safe and has an antibacterial effect against various microorganisms.

As an academic definition, the microorganism includes not only Bacteria (Bacteria), but also fungi (mushroom, mold, yeast, etc.), viruses, microalgae, and the like, but in the present specification, the microorganism means Bacteria (Bacteria).

The microorganism in the microorganism growth inhibitor of the present invention is preferably at least one selected from the group consisting of alicyclobacillus bacteria, bacillus bacteria, clostridium bacteria, and staphylococcus bacteria.

Further, the microorganism is more preferably at least one selected from the group consisting of Alicyclobacillus acidoterrestris (Alicyclobacillus acidoterrestris), Bacillus cereus (Bacillus cereus), Clostridium perfringens (Clostridium perfringens), Clostridium difficile (Clostridium difficile), and Staphylococcus aureus (Staphylococcus aureus). Isoxanthohumol exhibits an antibacterial effect against the above-mentioned microorganisms.

Bacillus acidoterrestris is a bacterium belonging to the genus Alicyclobacillus (Bacillus alicyticus) which is a gram-positive spore-forming bacterium, and is a thermophilic acidophilic bacterium. The thermophilic acidophilic bacteria is not easily killed by ordinary heat sterilization even under acidic conditions of pH6.5 or less, and has an effect of converting ferulic acid in fruit juice into guaiacol which is a cause of foreign odor. Therefore, it is known that the quality of the food or drink deteriorates when it grows. As a main prevention strategy, sterilization under a higher temperature condition than the standard, use of benzoic acid, or the like can be cited, but there is a problem that the former destroys the flavor of the beverage, and the latter is a synthetic preservative and is contraindicated.

Bacillus cereus is a gram-positive facultative anaerobic Bacillus belonging to the genus Bacillus, and forms spores. It is a food poisoning bacterium which is often present in nature such as soil or sewage.

Clostridium perfringens, commonly known as "Clostridium perfringens", is an anaerobic bacillus belonging to the genus Clostridium. Is a permanent bacterium in the intestinal tract of human beings or animals, and is widely distributed in natural environments such as soil. In clostridium perfringens, enterotoxin-producing bacteria are causative bacteria of food poisoning.

Clostridium difficile inhabits the natural environment such as soil, hay, sand, etc., or the intestinal tract and feces of humans or animals. The bacterium forms a proximal spore, and is stable in harsh environments such as acid, alkali, aerobic conditions, high temperature, and low nutrient conditions.

Staphylococcus aureus is a gram-positive facultative anaerobic coccus. The bacteria are resident bacteria existing on the skin surface and pores of a human body. Enterotoxigenic strains produce toxins when propagated in food. Staphylococcal food poisoning occurs due to the ingestion of enterotoxins simultaneously with the ingestion of food products. Enterotoxin is heat resistant (100 ℃, 30 minutes), does not deactivate in normal cooking, and is stable even in freezing. The toxicity among staphylococci, which are often present in human skin, is high.

The microorganisms are listed as test targets as harmful bacteria for foods and beverages, and in particular, thermophilic bacteria (Alicyclobacillus acidoterrestris) are bacteria whose proliferation is a risk of causing problems in acidic beverages.

The present invention also provides a method for preventing microbial contamination of a beverage, characterized in that isoxanthohumol is added so as to be 25 ppm by mass or more.

When isoxanthohumol is added to a beverage in an amount of 25 ppm by mass or more, a growth inhibitory effect on microorganisms including thermotolerant bacteria can be sufficiently obtained.

Further, isoxanthohumol is more preferably added so as to be 50 mass ppm or more. This is because the growth inhibitory effect against various microorganisms, that is, the antibacterial activity can be sufficiently obtained.

Although the microbial contamination prevention effect can be expected as the amount of isoxanthohumol added is increased, it is preferable to add isoxanthohumol to the beverage of the present invention so that the amount of isoxanthohumol is 500 ppm by mass or less in the method for preventing microbial contamination of a beverage of the present invention from the viewpoint of maintaining the original flavor of the beverage.

Isoxanthohumol is preferably added to the beverage in an amount of 25 to 500 ppm by mass, and more preferably in an amount of 50 to 500 ppm by mass.

In addition, isoxanthohumol has a characteristic sour taste and a bitter taste, and is a substance showing a bitter taste and a sour taste when a large amount of beverages are blended.

Here, the bitterness or sourness is included in the sweetness, sourness, bitterness, saltiness (bittern) and umami as 5 basic tastes, and is a sensation generated by stimulation of taste buds on the tongue. The taste or the degree of deliciousness of the food or drink is constituted by various elements, and in addition to the above-mentioned basic taste perceived by the taste buds, the taste, the temperature sensation and the smell perceived by the sense of smell which directly irritate the skin in the oral cavity are also influenced, and the taste and the degree of deliciousness are perceived as complementing various information.

Here, as a method for improving sourness or bitterness of beverages and the like, a method of adding a sugar, an amino acid, a nucleic acid, or the like having a sweet taste is generally known. These methods do not eliminate the sour or bitter taste itself, but rather mask the sour and bitter taste with strong sweetness.

However, the sweet taste is most easily perceived in the temperature (37 ℃) band around human skin, and tends to be hardly perceived in the low temperature region (5 ℃ or lower) and the high temperature region (55 ℃ or higher) due to the addition of temperature stimulation. On the other hand, bitterness and sourness are easily perceived even in a low temperature region, and sourness tends to be easily perceived even in a high temperature region. Therefore, even if the same ingredients are contained in a beverage at room temperature (25 ℃) and a beverage at a low temperature (5 ℃ or lower), the low-temperature beverage is less likely to feel a sweet taste and is likely to feel a bitter taste and a sour taste. On the other hand, a beverage at room temperature is easily perceived as sweet, and bitterness and sourness are masked by sweet taste and are hardly perceived.

Solid foods and beverages are different from liquids in the state, and since a beverage as a liquid quickly spreads in the oral cavity after being taken, and a large number of taste buds on the tongue come into contact with the taste buds, the beverage tends to have a strong taste sensation.

In this way, the degree of perception of the taste or the deliciousness of the food or drink by humans affects the temperature or the state of the food or drink, in addition to the components and the amounts of the components contained in the food or drink.

From the viewpoint of the flavor of the beverage, isoxanthohumol is added more preferably to the beverage in an amount of 200 ppm by mass or less, and still more preferably to the beverage in an amount of 180 ppm by mass or less. The beverage according to one embodiment of the present invention preferably contains isoxanthohumol in an amount of 200 ppm by mass or less, and more preferably contains isoxanthohumol in an amount of 180 ppm by mass or less.

The microbial growth inhibitor and the method for preventing microbial contamination of a beverage of the present invention are preferably used for a beverage having a ph of 4.6 or less, and more preferably a beverage having a ph of 4.0 or less. This is because substances having a pH of less than 4.0 need to be heat-sterilized at 65 ℃ for 10 minutes or equal or more, and substances having a pH of 4.0 or more and less than 4.6 need to be heat-sterilized at 85 ℃ for 30 minutes or equal or more, according to the production standards described in the Japanese food sanitation Law, and there is a possibility that the risk of contamination by thermophilic bacteria remains in such heat-sterilization treatment.

In one embodiment, the method for preventing microbial contamination of a beverage of the present invention preferably includes a step of adjusting the pH of the beverage to 4.6 or less. As described above, the method for preventing microbial contamination of a beverage of the present invention is suitable for preventing contamination by Thermus acidophilus in a beverage. Further, the method of the present invention more preferably comprises a step of adjusting the pH of the beverage to 4.0 or less. This is because substances having a pH of less than 4.0 need to be heat-sterilized at 65 ℃ for 10 minutes or equal or more, and substances having a pH of 4.0 or more and less than 4.6 need to be heat-sterilized at 85 ℃ for 30 minutes or equal or more, according to the production standards described in the Japanese food sanitation Law, and there is a possibility that the risk of contamination by thermophilic bacteria remains in such heat-sterilization treatment.

In addition, the pH of the beverage may be adjusted to less than 4.6, and may also be adjusted to less than 4.0.

The pH of the beverage may be the pH described above.

The pH can be adjusted by a known method such as adding a pH adjuster as needed. The pH can be measured by a commercially available pH meter.

In the method for preventing microbial contamination of a beverage, the microorganism is preferably at least one selected from the group consisting of bacteria belonging to the genus Alicyclobacillus, bacteria belonging to the genus Bacillus, bacteria belonging to the genus Clostridium, and bacteria belonging to the genus Staphylococcus.

Further, the microorganism is more preferably at least one selected from the group consisting of Alicyclobacillus acidoterrestris, Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus. Isoxanthohumol is effective in preventing contamination of the beverage with the above microorganisms.

The beverage using the microbial growth inhibitor and the method for preventing microbial contamination according to the present invention is described in detail below, and preferably an alcoholic beverage, a nonalcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, or a fruit or vegetable beverage. This is because the pH of the beverage is 4.6 or less, and it is expected that the beverage has an antibacterial effect against various microorganisms derived from acidobacter acidophilus, which is harmful to acidic beverages, bacteria belonging to the genus Bacillus (Bacillus cereus), clostridium and staphylococcus. Among these, the use in nonalcoholic beer-flavored beverages, carbonated beverages, functional beverages, or fruit and vegetable beverages is more preferable, and the use in functional beverages, or fruit and vegetable beverages is even more preferable. This is because the potential for proliferation of thermotolerant bacteria is high.

The present invention also provides a beverage containing isoxanthohumol in a range of more than 50 ppm by mass and not more than 180 ppm by mass, and having a pH of not more than 4.6.

This is because a beverage having a ph of 4.6 or less can have a sufficient antimicrobial activity against various microorganisms, that is, a microorganism growth inhibitory effect, by containing isoxanthohumol in an amount of more than 50 mass ppm. Further, since the content of isoxanthohumol is 180 mass ppm or less, a sufficient effect of inhibiting the growth of microorganisms can be obtained without spoiling the flavor of a beverage having a ph of 4.6 or less.

In accordance with the production standard described in the Japanese food sanitation Law, a substance having a pH of less than 4.0 needs to be heat-sterilized at 65 ℃ for 10 minutes or equal or more, and a substance having a pH of 4.0 or more and less than 4.6 needs to be heat-sterilized at 85 ℃ for 30 minutes or equal or more, and there is a possibility that a problem of contamination by thermophilic acidophilic bacteria occurs in such heat-sterilization treatment. For example, when the sterilization temperature and time required to reduce the viable cell count of the genus Alicyclobacillus to 1/10 are reported as a heating temperature of 90 ℃, it takes 10 minutes or more (food and container 2015VOL.56NO. 3). Therefore, when the refreshing beverage is sterilized under the conditions described in the japanese food sanitation act, the acidophilic thermophilic bacteria may not be absolutely sufficiently killed in the refreshing beverage having a pH of less than 4.6.

The beverage of the present invention preferably contains not less than 60 ppm by mass of isoxanthohumol.

The content of isoxanthohumol can be determined, for example, by quantitative analysis using High Performance Liquid Chromatography (HPLC) or an LC-MS/MS system (TSQ Quantiva, Thermo Fisher Scientific Co.). As a method for measuring isoxanthohumol by High Performance Liquid Chromatography (HPLC), for example, the following conditions can be mentioned.

(basic conditions)

The device comprises the following steps: SHIMADZU LC-20AD (Shimadzu Co., Ltd.)

Flow rate: 1.0 mL/min

Analysis time: 25 minutes/sample

Pipe column: nomura chemcals Develosil C30-UG-5, 4.6mm phi x 150mm

Column temperature: 40 deg.C

A detector: SPD-20A

Detection wavelength: 280nm

(Mobile phase)

Phase A: 0.1% aqueous formic acid solution

Phase B: 0.1% acetonitrile containing formic acid

(gradient conditions)

The gradient conditions are shown in table 1 below. The ratio (%) of the B phase was v/v%.

[ Table 1]

The beverage of the present invention is preferably an alcoholic beverage, nonalcoholic beer-flavored beverage, carbonated beverage, functional beverage, or fruit and vegetable beverage.

Examples of the alcoholic beverages include beer, beer-like beverages, and alcoholic beverages other than beer and beer-like beverages.

When the beverage of the present invention is a beer-based beverage, happoshu or third beer is preferable.

When the beverage of the present invention is an alcoholic beverage other than beer and beer-like beverages, distilled liquor, carbonated distilled liquor, liqueur, cocktail, spirit, whisky are preferable.

The term "nonalcoholic beer-flavored beverage" as used herein means a carbonated beverage having a beer-like flavor, and is of a non-fermented nonalcoholic type and contains substantially no alcohol. Here, the non-alcoholic beer-flavored beverage does not exclude a beverage containing an undetectable amount of alcohol.

When the beverage of the present invention is a carbonated beverage, it is preferably a cola-flavored beverage, a clear carbonated beverage, a ginger carbonated beverage, a fruit juice-based carbonated beverage, a milk-based carbonated beverage or a sugar-free carbonated beverage.

When the beverage of the present invention is a functional beverage, it is preferably a sports beverage, an energy beverage, a health supplement beverage or a jelly drink in a pouch.

When the beverage of the present invention is a fruit or vegetable beverage, a 100% fruit beverage, a fruit-containing beverage, a low-content fruit juice refreshing beverage, a fruit beverage or a fruit pulp beverage containing fruit particles is preferable.

The beverage of the present invention is preferably a nonalcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, or a fruit-and vegetable-based beverage, and more preferably a functional beverage, or a fruit-and vegetable-based beverage. The pH of the beverage at this time is 4.6 or less, and may be less than 4.6. Further, the pH is preferably 3.0 or more.

In a preferred embodiment, the beverage of the present invention has an antibacterial effect against various microorganisms, and is useful as a beverage for suppressing contamination by microorganisms. Among them, the beverage has an antibacterial action against thermophilic acidophilic bacteria, and is therefore particularly useful as a beverage for suppressing contamination by thermophilic acidophilic bacteria.

The beverage of the present invention is preferably a beverage provided in a low temperature region of 5 ℃ or lower (e.g., 4 to 5 ℃) or a high temperature region of 55 ℃ or higher (e.g., 55 to 95 ℃). This is because the beverage of the present invention contains isoxanthohumol having an antibacterial activity, but the flavor of the beverage is not spoiled even in a low temperature region where bitterness and sourness are easily perceived or a high temperature region where sourness is easily perceived because the isoxanthohumol is contained at a specific concentration to such an extent that the flavor of the beverage is not spoiled.

The form of the beverage is not particularly limited, and the beverage can be made into a packaged beverage. The container for the packaged beverage is not particularly limited, and any type and material of the container can be used, for example, a metal container such as an aluminum can or a steel can; resin containers such as PET bottles; paper containers such as cartons; glass containers such as glass bottles; any of commonly used containers such as wooden barrels. By filling and sealing the beverage into such a container, a container-packaged beverage can be obtained.

The beverage may be prepared, for example, by formulating isoxanthohumol into a substance used in the manufacture of the beverage (e.g., any food material or food additive).

Examples

The following shows embodiments that more particularly illustrate the invention. The present invention is not limited to these examples.

< preparation example 1 >

Preparation of isoxanthohumol

Isoxanthohumol was isolated and purified from a hop extract (manufactured by Asama Chemical Co., Ltd.) by the following method. That is, the isoxanthohumol is purified by normal phase column chromatography, reversed phase column chromatography, preparative HPLC purification, using hop extract as a raw material, and the purity is determined to be 95% or more by HPLC analysis. In addition, in HPLC analysis, Develosil C30-UG-5 (Nomura chemical Co.) was used as a column, and the ultraviolet absorption measurement wavelength of the detector was set to 280 nm. The obtained isoxanthohumol was used as a standard (purity 95% or more) in the following experiment.

< example 1 >

As test Bacteria, test Bacteria solutions were obtained by preculture of the following microorganisms (Bacteria ). The preculture conditions were as follows. The thermophilic acidophilic bacteria were aerobically cultured at 50. + -. 1 ℃ for 2 days using YSG broth. Bacillus cereus and Staphylococcus aureus were aerobically cultured at 37. + -. 1 ℃ for 18 to 20 hours using Mueller Hinton Broth (manufactured by Difco Japanese Bidi Co.). Clostridium perfringens was anaerobically cultured at 35. + -. 1 ℃ for 18 to 20 hours using GAM Broth (Nichiyu pharmaceutical Co., Ltd.). Clostridium difficile (spore) was anaerobically cultured at 37. + -. 1 ℃ for 7 days using BHIA medium supplemented with taurocholic acid.

(test bacteria)

Thermus acidophilus (Alicyclobacillus acidoterrestris ATCC 49025)

Bacillus cereus (Bacillus cereus IFO 13494)

Clostridium perfringens (Clostridium perfringens JCM 1290)

Clostridium difficile (spores) (Clostridium difficile ATCC 9689)

Staphylococcus aureus (Staphylococcus aureus subsp. aureus NBRC 12732)

A10 mg/mL solution of isoxanthohumol and a 2-fold diluted concentration thereof were prepared using 99.5% ethanol, respectively. Then, after sterilization and dissolution, 1/99 (volume of isoxanthohumol solution/volume of medium solution) was added to a predetermined medium (shown in table 2 below) stored at 50 ± 1 ℃, and the solutions were mixed well, dispensed to a petri dish, and solidified to prepare an agar plate medium.

Then, the test bacterial liquid obtained by the previous culture was smeared on the agar plate medium, and after culturing under the predetermined culture conditions described in table 2 below, the minimum growth inhibitory concentration (MIC) was determined to be the minimum concentration at which the growth of the microorganism was inhibited. The results are shown in Table 3 below.

< culture conditions >

[ Table 2]

[ Table 3]

It is clear that isoxanthohumol prevents the development of the above-mentioned various microorganisms and has an antibacterial action, i.e., a microorganism proliferation-inhibiting action.

Industrial applicability

The microbial growth inhibitor, the method for preventing microbial contamination of a beverage, and the beverage of the present invention are useful in the field of foods and beverages.