WO2024080236A1

WO2024080236A1 - Food, drink, and antimicrobial agent

Info

Publication number: WO2024080236A1
Application number: PCT/JP2023/036513
Authority: WO
Inventors: 敦吉田; 将一村田; 吉満　斉; 裕幸宮下
Original assignee: サントリーホールディングス株式会社
Priority date: 2022-10-14
Filing date: 2023-10-06
Publication date: 2024-04-18

Abstract

Food, drink, and antimicrobial agent according to the present invention contain at least one of six natural product-derived compounds represented by formulas 1-6 described in the description, or salts thereof. These compounds are each a natural product-derived antimicrobial component that is suitable for use in food and drink, and that exhibits the effect of inhibiting the growth of microorganisms in food and drink when used at a concentration that is similar to or lower than that of existing synthetic preservatives for food and drink, such as sodium benzoate. In addition, the compounds have the advantage of being less likely to hurt the commodity value of food products and drink products.

Description

Food, beverages and antibacterial agents

The present invention relates to food and beverage products that contain one or more specific compounds. More specifically, the present invention relates to food and beverage products that contain one or more specific compounds derived from natural products, thereby inhibiting the growth of microorganisms. The present invention also relates to antibacterial agents that contain specific compounds derived from natural products.

An antibacterial agent or preservative is an additive that inhibits the growth of microorganisms that cause spoilage or deterioration of food and beverages, and enhances the shelf life. Synthetic preservatives or synthetic antibacterial agents such as sodium benzoate and potassium sorbate are commonly used as antibacterial agents or preservatives for beverages. However, the effects of synthetic preservatives on the intestinal flora have been shown in recent years, raising concerns about their impact on health. It is also said that sodium benzoate poses the risk of producing carcinogenic benzene by reacting with vitamin C. In addition to the health effects, sodium benzoate has a unique astringent taste (Patent Document 1), which may affect the flavor of the beverage, and potassium sorbate has a low growth inhibition effect on certain microorganisms and also has the problem of having a unique odor.

In order to reduce the use of synthetic preservatives such as those mentioned above, preservatives derived from natural products are being investigated (Patent Document 2, Patent Document 3).

JP 2020-171301 A Japanese Patent Application Laid-Open No. 5-7482 Japanese Patent Application Laid-Open No. 2-211856

Although there are cases where antimicrobial agents or preservatives derived from natural products have been investigated, there are few cases where it has been confirmed that they actually inhibit the growth of microorganisms in food and beverages. Furthermore, there are even fewer cases where it has been confirmed that they do not impair the commercial value of the food and beverages, such as the stability of appearance or taste. As consumer preferences have become more diverse in recent years, the types of food and beverage products, such as beverage products, have become more diverse, and it is desirable to search for new antimicrobial agents derived from natural products that are suitable for use in food and beverages, so as to be able to respond to the various properties and flavors of a wide variety of food and beverage products.

The inventors conducted a search for compounds derived from natural products suitable for use as preservatives (microbial growth inhibitors) in food and beverage products, and discovered six types of compounds that have the effect of inhibiting microbial growth. These compounds were then added to commercially available beverages and confirmed to have the effect of inhibiting microbial growth. They also found that these compounds have the appearance stability required for products (the property of being less susceptible to changes in appearance over time), which led to the present invention. Specifically, the six types of compounds are compounds represented by formulas 1 to 6, which are explained in the "Form for carrying out the invention" section below.

The present invention relates to a food or beverage containing one or more of the compounds represented by formulas 1 to 6 or salts thereof. The present invention also relates to a beverage containing one or more of the compounds represented by formulas 1 to 6 or salts thereof. The present invention also relates to a method for producing a food or beverage, which includes adding one or more of the compounds represented by formulas 1 to 6 or salts thereof. The present invention also relates to an antibacterial agent, preferably an antibacterial agent for food or beverage, containing one or more of the compounds represented by formulas 1 to 6 or salts thereof. The antibacterial agent preferably inhibits the growth of one or more microorganisms of the genus Brettanomyces, Saccharomyces, Zygosaccharomyces, Neosartorya, or Alicyclobacillus. The present invention also relates to a compound represented by formula 2, which is a novel compound, and a compound represented by formula 3.

All of the compounds represented by formulas 1 to 6 are compounds obtained from natural products, but to the inventors' knowledge, there have been no reports to date of actually adding these compounds to food and beverage products and confirming their microbial growth inhibitory effect and commercial value as food and beverage products.

The food and drink of the present invention contains one or more of the compounds represented by formulas 1 to 6 or their salts, which inhibits the growth of microorganisms in the food and drink and exhibits high preservation properties. All of the compounds represented by formulas 1 to 6 are compounds derived from natural products. The food and drink of the present invention, which contains one or more of the compounds represented by formulas 1 to 6, may be able to obtain a microbial growth inhibitory effect without using synthetic preservatives such as sodium benzoate and potassium sorbate, or while reducing the amount of these preservatives used, in foods and drinks that have traditionally required such preservatives. When synthetic preservatives are used, they are generally added to beverages at about 200 to 400 ppm, but the compounds represented by formulas 1 to 6 or their salts may exhibit a microbial growth inhibitory effect even at concentrations equal to or lower than those of the synthetic preservatives. The compounds represented by formulas 1 to 6 or their salts may be added to the food and drink in one or a combination of two or more of them. The compound to be used may be selected according to the type and flavor of the food and drink.

Furthermore, the compounds represented by formulas 1 to 6 have the advantage that when added to food or beverages, they are unlikely to change the appearance of the food or beverage and are unlikely to impair the commercial value of the food or beverage. When used at a concentration at which an antibacterial effect is obtained, the compounds of formulas 1 to 6 may exhibit a degree of appearance stability that does not impair commercial value, similar to the use of sodium benzoate at the same concentration. Furthermore, when used at a concentration at which an antibacterial effect is obtained, they may have the advantage that they are unlikely to affect the flavor and taste of the food or beverage and are unlikely to impair commercial value, compared to the use of sodium benzoate at a concentration at which an antibacterial effect is obtained.

The present invention relates to a beverage containing one or more of the compounds represented by the following formulas 1 to 6 or salts thereof. Hereinafter, the compound represented by formula 1 will be abbreviated as "compound 1" and the compound represented by formula 2 will be abbreviated as "compound 2." Compounds 1 to 6 are all compounds obtained from natural products. Specifically, they are compounds obtained by extraction and purification from Akebia quinata.

Compound 1 (CAS No. 27013-91-8) is a compound having the following formula 1:

Compound 2 is a compound having the following formula 2. Compound 2 is a novel compound that has not been reported so far as the inventors know. The inventors have confirmed that when compound 2 is used in beverages, it exhibits a growth inhibitory effect against microorganisms (yeasts) of the genera Zygosaccharomyces, Saccharomyces, and Brettanomyces at very low concentrations, and also exhibits a growth inhibitory effect against mold (Neosartoria genus). Furthermore, thermoacidophilic bacteria, which have high heat resistance even in strong acidic regions, are known to be microorganisms that cause the spoilage and decay of food and beverages. The inventors have confirmed that when compound 2 is used in beverages, it exhibits a growth inhibitory effect against thermoacidophilic bacteria (Alicyclobacillus genus) at very low concentrations.

Compound 3 is a compound having the following formula 3. Compound 3 is a novel compound that has not been reported so far as the inventors know. The inventors have confirmed that when compound 3 is used in a beverage, it exhibits a growth inhibitory effect against microorganisms (yeasts) of the genera Zygosaccharomyces, Saccharomyces, and Brettanomyces, particularly against the genera Saccharomyces and Brettanomyces, at very low concentrations. Furthermore, the inventors have confirmed that when compound 3 is used in a beverage, it also exhibits a growth inhibitory effect against thermoacidophilic bacteria (genus Alicyclobacillus) at very low concentrations.

Compound 4 (CAS No. 17184-21-3) is a compound having the following formula 4.

Compound 5 (CAS No. 35790-95-5) is a compound having the following formula 5.

Compound 6 (CAS No. 1309688-49-0) is a compound having the following formula 6:

Compounds 1 to 6 can be obtained by extraction and purification from Akebia quinata. In addition to Akebia quinata, they can also be obtained by extraction and purification from black cumin and Eleuthero. When compounds 1 to 6 are used in the food and drink or antibacterial agent of the present invention, they may be extracted from these natural products. Compounds 1 to 6 may be purified, may be in the state extracted from the natural product, or may be in the form of a concentrate of the extract. The method of extraction and purification of compounds 1 to 6 is not particularly limited. For example, natural products containing compounds 1 to 6, such as Akebia quinata, can be chopped, immersed in an extraction solvent such as methanol for a certain period of time, and then filtered. The extract obtained by filtration can be concentrated by a known method such as vacuum concentration. Compounds 1 to 6 can be purified from the extract or concentrate using a known purification method such as column chromatography. The presence of compounds 1 to 6 in the extract can be confirmed by using a normal method used in the analysis of triterpene compounds.

When compounds 1 to 6 are used in the food or beverage or antibacterial agent of the present invention, if a commercially available product of each compound is available, it may be used. Alternatively, each compound may be obtained by synthesis using any method.

Compounds 1 to 6 may be in the form of any salt.
(Food and beverages)
The food or drink of the present invention contains any one or more of the above compounds 1 to 6 or salts thereof. Depending on the type of food or drink and the degree of the desired microbial growth inhibitory effect, and taking into consideration the effect on the flavor of the food or drink, one or more of the compounds 1 to 6 or salts thereof may be used in combination. The food or drink is preferably a beverage.

The amount of each compound used in a food or beverage is not particularly limited, as long as it is an amount that can obtain the effect of inhibiting the proliferation of microorganisms in the food or beverage. For example, the lower limit is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, more preferably 1.0 ppm or more, even more preferably 10 ppm or more, even more preferably 20 ppm or more, and even more preferably 30 ppm or more, as the total concentration of compounds 1 to 6 or their salts. In addition, in order to minimize the effect on the flavor and appearance of the food or beverage, it is preferable to set the amount of compounds 1 to 6 used in the food or beverage as small as possible within the range in which the desired effect can be obtained. For example, the upper limit is preferably 500 ppm or less, more preferably 400 ppm or less, more preferably 300 ppm or less, even more preferably 250 ppm or less, even more preferably 125 ppm or less, even more preferably 100 ppm or less, and even more preferably 50 ppm or less.

When the food or beverage of the present invention is a beverage, it may be a ready-to-drink beverage, or a concentrated beverage to be diluted and consumed. In the case of a concentrated beverage, compounds 1 to 6 or a salt thereof may be used so that the above content is satisfied in the concentrated beverage, with the intention of obtaining a microbial growth inhibitory effect during storage in a concentrated state. Alternatively, when the intention is to obtain a microbial growth inhibitory effect during storage of a concentrated beverage in a diluted state, compounds 1 to 6 or a salt thereof may be contained in the concentrated beverage in an amount obtained by multiplying the above content by a predetermined dilution level of the beverage, so that the above content is satisfied in the diluted state, according to the predetermined dilution level of the concentrated beverage.

　Conventional synthetic preservatives such as sodium benzoate and potassium sorbate are generally used in beverages at concentrations of about 200 to 400 ppm, for example. Compounds 1 to 6 or their salts may be able to achieve a microbial growth inhibitory effect in beverages at concentrations similar to or lower than those of conventional synthetic preservatives. In addition, compounds 1 to 6 or their salts tend not to impair the commercial value of beverage products, such as their appearance stability and flavor.

The method for measuring the content of each compound in food and beverages is not particularly limited. For example, a standard sample of each compound can be prepared, and measurements can be made using HPLC or the like, with conditions set according to the type of food and beverage.

The type of food or drink containing compounds 1 to 6 or a salt thereof is not particularly limited. For example, when the food or drink is a beverage, examples include carbonated beverages, beverages containing fruit juice, beverages containing vegetable juice, coffee beverages, tea beverages, cocoa beverages, jelly beverages, dairy beverages, lactic acid bacteria beverages, soy milk, soups, nutritional drinks, sports beverages, alcoholic beverages, and concentrated beverages that are diluted and consumed. Among these, acidic beverages with a pH of 2 to 5 (preferably pH 2.5 to 4.5) are beverages that have traditionally often used synthetic preservatives, and are therefore preferred as types of beverages that contain compounds 1 to 6 or a salt thereof. Examples of acidic beverages include carbonated beverages, beverages containing fruit juice, beverages containing vegetable juice, lactic acid bacteria beverages, nutritional drinks, and sports beverages. They may be ready-to-drink beverages, or concentrated beverages that are diluted and consumed. The type of fruit juice or vegetable juice is not particularly limited, and examples include citrus fruit juice (lemon, grapefruit, lime, oranges, Satsuma mandarins, tangor, summer mandarins, sweet summer oranges, hassaku citrus, hyuganatsu, shekwasha, sudachi, yuzu, kabosu, daidai, iyokan, ponkan, kumquat, sanbokan, oroblanco, pomegranate, etc.), black currant juice, apple juice, grape juice, peach juice, tropical fruit juice (pineapple, guava, banana, mango, acerola, papaya, passion fruit, lychee, etc.), plum juice, pear juice, apricot juice, plum juice, berry juice, kiwi fruit juice, cherry juice, chestnut juice, watermelon juice, tomato juice, carrot juice, strawberry juice, melon juice, etc.

Furthermore, even if the food or drink is food other than beverages, there is no particular limit to the type, and examples include sauces, confectionery, bread, meat, minced fish, frozen foods, retort foods, brewed foods, seasonings, dairy products, and prepared foods.

The food and drink of the present invention is preferably a food and drink that uses one or more of compounds 1 to 6 or a salt thereof in place of a synthetic preservative that has conventionally been used, or in a form that replaces a part of the synthetic preservative. Compounds 1 to 6 or a salt thereof are preferably intentionally added separately from the usual components of various foods and drinks, for the purpose of enhancing the microbial growth inhibitory effect of the foods and drinks.

The food and drink of the present invention is preferably a food and drink in which the proliferation of microorganisms is suppressed when the food and drink is added with microorganisms and stored at room temperature for two weeks, compared to a food and drink (comparative food and drink) having the same composition except that it does not contain compounds 1 to 6 or salts thereof. Here, the microorganisms are those that cause the deterioration or decay of the food and drink, such as yeast and mold. Typical examples of yeast that cause deterioration or decay include the genus Brettanomyces, the genus Saccharomyces, and the genus Zygosaccharomyces. Also, typical examples of mold include the genus Neosartorya. The food and drink of the present invention is preferably a food and drink in which the proliferation of one or more of these microorganisms is suppressed, compared to the comparative food and drink. Also known as microorganisms that cause the deterioration or decay of beverages are thermoacidophilic bacteria (such as bacteria of the genus Alicyclobacillus) that have high heat resistance even in a strong acidic range. The beverage of the present invention preferably has suppressed growth of thermoacidophilic bacteria compared to the comparative beverages described above.

The phrase "microorganism growth is inhibited" compared to a comparative food or drink means that the growth of microorganisms that cause the food or drink to spoil or decay is less than that in the comparative food or drink. When microorganisms are added and the food or drink is stored at room temperature for two weeks, the fact that the growth of microorganisms is less than that in the comparative food or drink indicates that the growth of the added microorganisms is inhibited by the presence of compounds 1 to 6 or salts thereof in the food or drink. Room temperature is 10 to 30°C, preferably about 25 to 28°C. Depending on the type of microorganism, it may be more appropriate to conduct the test at a temperature other than room temperature. Specific test methods for confirming the growth of microorganisms include, for example, the methods described in the Examples below.

The food and drink of the present invention is more preferably a food and drink that, when added with microorganisms and stored for two weeks at room temperature or at a temperature suitable for microbial growth, shows very little microbial growth and therefore shows no deterioration or spoilage. Even more preferably, the food and drink is one in which microorganisms do not grow.

The food and drink of the present invention is also preferably a food and drink that has a degree of appearance stability that does not impair the commercial value of the food and drink. Appearance stability refers to the property of the appearance of the food and drink not changing easily over time. For example, it refers to little change in the appearance of the food and drink when the product is sealed in a packaging container or the like and stored at room temperature for about two weeks. The food and drink of the present invention is also preferably a food and drink that contains compounds 1 to 6 or a salt thereof, but that changes little from the original color and taste of the food and drink (the color and taste of a food and drink that has the same composition except that it does not contain compounds 1 to 6 or a salt thereof).

(Production method)
The present invention also provides a method for producing a food or drink, which includes adding any one or more of compounds 1 to 6 or salts thereof. The method of the present invention includes a step of adding any one or more of compounds 1 to 6 or salts thereof during a normal production process of a food or drink. The timing of addition of each compound is not particularly limited, and the compounds may be added at any stage of the production process of the food or drink. For example, the compounds 1 to 6 or salts thereof may be added and mixed when adding and mixing normal ingredients of the food or drink, or the compounds 1 to 6 or salts thereof may be added and mixed after normal preparation of the food or drink. The compounds 1 to 6 or salts thereof to be added are preferably those obtained by extraction and purification from the above-mentioned natural products. Alternatively, they may be in the form of an extract of a natural product, or may be in the form of a concentrate of the extract. Alternatively, a commercially available product of each compound may be used, or may be obtained by synthesis by any method. The compounds 1 to 6 or salts thereof to be added may be in a solid form such as a powder, or may be in a liquid form dissolved or suspended in any solvent. The method for adding each compound is also not particularly limited, and for example, a method for adding and mixing ingredients in the production of a normal food or drink may be used.

The amount of Compounds 1 to 6 or a salt thereof to be added is not particularly limited as long as it is an amount that can obtain the microbial growth inhibitory effect in the food or drink to be produced, as described above.
The type of food and drink is not particularly limited, and examples include those mentioned above.

(Antibacterial Agent)
The present invention also provides an antibacterial agent comprising any one or more of compounds 1 to 6 or salts thereof.
The antibacterial agent of the present invention contains at least one of Compounds 1 to 6 or a salt thereof as an antibacterial, i.e., microbial growth inhibiting, active ingredient. The amount of Compounds 1 to 6 or a salt thereof contained in the antibacterial agent is not particularly limited as long as it is an amount that can obtain the desired effect of inhibiting microbial growth, and is, for example, about 1 to 40% by mass, and preferably about 1 to 20% by mass.

The dosage form of the antibacterial agent of the present invention is not particularly limited, and may be in a solid form such as powder, granules, or tablets, or may be in a liquid or paste form dissolved or suspended in any solvent. Depending on the dosage form, the antibacterial agent of the present invention may contain components other than Compounds 1 to 6 or salts thereof, such as various solvents, excipients, fragrances, pH adjusters, antioxidants, stabilizers, specific gravity adjusters, etc.

The antibacterial agent of the present invention is preferably an antibacterial agent for food and beverages, intended to inhibit the growth of microorganisms in such foods and beverages as described above, but can also be used in products other than food and beverages. Examples of products in which the antibacterial agent of the present invention can be used include household products such as kitchen detergents, laundry detergents, antibacterial sprays, toothpaste, cosmetics, household cleaners, soaps, and shampoos, as well as pet foods.

The antibacterial agent of the present invention may be contained in foods, beverages, or products other than foods and beverages as a flavoring or as part of a flavoring composition.

The details of the present invention will be specifically explained below with experimental examples, but the present invention is not limited thereto. Furthermore, in this specification, unless otherwise specified, numerical ranges are stated to include their endpoints.

(Yeast growth test in culture medium 1)
Compounds 1 to 6 obtained by extraction and purification from Mitellida octanoides were tested for their inhibitory effect on yeast proliferation in a potato dextrose liquid medium. The specific procedure is as follows.

　Commercially available potato dextrose medium powder was dissolved in water and sterilized. After sterilization, the pH of the medium was adjusted to 3.8 using sulfuric acid. Each of compounds 1 to 6 was dissolved in dimethyl sulfoxide (DMSO), and the resulting solutions of each compound were added to the medium in triplicate to give three final concentrations of 7.8 ppm, 31 ppm, and 125 ppm. A 96-well microplate was prepared, and 240 μL of the medium to which each of compounds 1 to 6 had been added at each concentration was dispensed into each well.

A bacterial solution of 10,000 cfu/mL was prepared for each of the three types of yeast (Zygosaccharomyces bailii, Saccharomyces cerevisiae, and Brettanomyces sp.).

10 μL of each yeast cell suspension was added to each well to which a medium containing each of compounds 1 to 6 had been added. As a blank, 10 μL of saline was added to each well to which a medium containing each of compounds 1 to 6 had been added. In addition, a compound-free group was prepared in which 10 μL of each yeast cell suspension was added to 240 μL of medium containing no compounds 1 to 6.

These were stored at 28°C for two weeks. After storage, it was confirmed that yeast had grown in the compound-free area, and then the yeast growth was visually confirmed in the medium to which each compound had been added, compared with the blank. The results are shown in Table 1. The numbers in Table 1 indicate the lowest concentration at which the yeast growth inhibitory effect was obtained, among the concentrations of 7.8 ppm, 31 ppm, and 125 ppm prepared for each compound. For example, "31" indicates that the yeast growth inhibitory effect was not observed at a compound concentration of 7.8 ppm, but was obtained at 31 ppm and 125 ppm, and "7.8" indicates that the yeast growth inhibitory effect was obtained at all of 7.8 ppm, 31 ppm, and 125 ppm. In addition, ">125" indicates that the yeast growth inhibitory effect was not obtained at all of 7.8 ppm, 31 ppm, and 125 ppm.

The results in Table 1 show that compounds 1 to 6 have the effect of inhibiting the proliferation of yeast.
(Test for yeast and mold growth in beverages 2)
A commercially available carbonated beverage containing 1% lemon juice (containing sugars (fructose glucose liquid sugar, sugar), lemon juice, carbonic acid, flavoring, vitamin C, acidulant, safflower color, calcium pantothenate, vitamin B6, and carotene color) was used to confirm the growth inhibitory effects of compounds 1 to 6 and sodium benzoate for comparison against various yeasts and molds in the beverage. The specific procedure is as follows.

The beverage was opened and left to escape the carbon dioxide, after which the pH of the beverage was adjusted to 3.3 using an aqueous sodium hydroxide solution. Each of compounds 1 to 6 was dissolved in dimethyl sulfoxide (DMSO), and the resulting solutions of each compound were added to the beverage so that the final concentrations were as shown in Table 2. For comparison, an aqueous solution of sodium benzoate was added to the beverage so that the final concentrations were as shown in Table 2. A 96-well microplate was prepared, and 240 μL of the beverages containing various concentrations of each of compounds 1 to 6 and the beverages containing various concentrations of sodium benzoate were dispensed into each well.

Similar to Test 1, 10,000 cfu/mL bacterial solution was prepared for each of the three types of yeast (Zygosaccharomyces bailii, Saccharomyces cerevisiae, Brettanomyces sp.). 10,000 cfu/mL bacterial solution was also prepared for the mold (Neosartorya sp.).

10 μL of each bacterial solution was added to each well to which a beverage containing compounds 1-6 or sodium benzoate had been added. As a blank, 10 μL of saline was added to each well to which a beverage containing compounds 1-6 or sodium benzoate had been added. In addition, a compound-free group was prepared in which 10 μL of each bacterial solution was added to 240 μL of beverage containing neither compounds 1-6 nor sodium benzoate.

The microplates prepared as described above were stored at 28°C for two weeks. After storage, it was confirmed that yeast or mold had grown in the compound-free area, and then the growth of yeast or mold was visually confirmed in the beverages to which each compound had been added, in comparison with the blank. Specifically, the presence or absence of precipitation due to yeast or mold was visually confirmed, and confirmed precipitation was judged to indicate growth (+), and no confirmed precipitation was judged to indicate no growth (-). The results are shown in Table 2.

The results in Table 2 show that compounds 1 to 6 exhibit the effect of inhibiting the growth of various yeasts in existing carbonated beverages containing fruit juice at concentrations equal to or lower than sodium benzoate, which has known antibacterial properties. It is also shown that compounds 1, 2, 4, and 6 exhibit the effect of inhibiting the growth of mold in existing carbonated beverages containing fruit juice at concentrations equal to or lower than sodium benzoate.

(Thermoacidophilic bacteria growth test in beverages 3)
A commercially available grape juice beverage (containing fruit juice (grape, lemon), sugars (fructose, sugar), salt, lemon extract, shekwasha extract, Unshu mandarin extract, yuzu peel, dried tomato extract, flavoring, lactic acid, potassium chloride, and antioxidant (vitamin C)) was used to confirm the growth inhibitory effect of compounds 1 to 6 and sodium benzoate as a comparison against thermoacidophilic bacteria in the beverage. The specific procedure is as follows.

The beverage was opened, and the pH of the beverage was adjusted to 3.3 using an aqueous sodium hydroxide solution. Each of compounds 1 to 6 was dissolved in DMSO, and the resulting solutions of each compound were added to the beverage so that the final concentrations were as shown in Table 3. For comparison, a beverage was prepared to which sodium benzoate had been added so that the final concentrations were as shown in Table 3. 5 mL of each of the beverages to which compounds 1 to 6 had been added at various concentrations and the beverages to which sodium benzoate had been added at various concentrations were dispensed into test tubes.

A 15,000 cfu/mL solution of thermoacidophilic bacteria (Alicyclobacillus acidoterrestris) was prepared. 100 μL of the solution was added to each test tube containing a beverage containing compounds 1 to 6 or sodium benzoate. In addition, a compound-free group was prepared in which 100 μL of the solution was added to 5 mL of beverage containing neither compounds 1 to 6 nor sodium benzoate.

Each test tube prepared as described above was stored at 45°C for two weeks. After storage, 100 μL of the beverage was extracted from each test tube, smeared on YSGA medium, and then cultured for three days at 45°C or 55°C depending on the type of bacteria. After culture, the number of colonies formed on the medium was counted. The number of surviving bacteria in the solution was calculated based on the number of colonies, and bacteria that had grown 10 times or more compared to the inoculated number was considered to have grown (+), and bacteria that had grown less than 10 times was considered to have not grown (-). Note that under these conditions, the group without added compound showed growth (+). The results are shown in Table 3.

As shown in Table 3, at least compounds 1 to 6 were found to have a growth inhibitory effect on thermoacidophilic bacteria. The growth inhibitory effect of these compounds on thermoacidophilic bacteria was higher than that of sodium benzoate, an existing synthetic antibacterial agent.

(Evaluation of beverage appearance stability)
The appearance stability of Compounds 1 to 6 and sodium benzoate for comparison was evaluated using the commercially available carbonated drink containing 1% lemon juice used in Test 2. The specific procedure is as follows.

The beverages were opened and left to stand until the carbon dioxide had escaped, after which the pH of the beverages was adjusted to 3.3 using an aqueous solution of sodium hydroxide. Each of compounds 1 to 6 was dissolved in DMSO, and the resulting solutions of each compound were added to the beverages so that the concentrations of each compound were as shown in Table 4. For comparison, a beverage was prepared to which an aqueous solution of sodium benzoate had been added to the beverages so that the concentrations were as shown in Table 4. The beverages to which each of compounds 1 to 6 had been added at various concentrations and the beverages to which sodium benzoate had been added at various concentrations were dispensed in 3 mL portions into 15 mL centrifuge tubes.

Separately from the above, 3 mL of a beverage containing neither Compounds 1 to 6 nor sodium benzoate (compound-free group) was prepared as a control.
The centrifuge tubes prepared as described above were stored for one week at 28° C. After storage, the beverages containing compounds 1 to 6 or sodium benzoate were compared with a compound-free group and scored according to the following criteria.
0 points: no difference compared to the compound-free group 1 point: slight difference compared to the compound-free group 2 points: clear difference compared to the compound-free group 3 points: significant difference compared to the compound-free group, no commercial value as a beverage product In the above criteria, 0 to 2 points can be said to be suitable as a beverage product (has commercial beverage value), and 3 points can be said to be unsuitable as a beverage product (has no commercial beverage value). The results are shown in Table 4.

The results in Table 4 show that compounds 1 to 6 maintain the appearance stability without impairing the commercial value of the beverage even when used in a beverage at a concentration that exerts antibacterial activity.
(Evaluation of the effect on the flavor of beverages)
Using the commercially available carbonated beverage containing 1% lemon juice used in Test 2, the effect on the flavor of the beverage was evaluated when Compound 1 or sodium benzoate as a comparison was added at a concentration at which the yeast growth inhibitory effect in the beverage was confirmed in Test 2. The specific procedure is as follows.

Compound 1 or sodium benzoate was added to the beverage to the concentration shown in Table 4. The flavor of the obtained beverage was evaluated by a panel of five experts. Specifically, a beverage to which neither Compound 1 nor sodium benzoate was added was used as a control, and each expert evaluated the extent to which the flavor was changed by adding Compound 1 or sodium benzoate at each concentration compared to the control, and whether the commercial value was impaired by the change in flavor, according to the following criteria. In the following criteria, a score of 1 or less can be said to be suitable as a beverage product (has commercial beverage value), and a score of 2 or more can be said to be unsuitable as a beverage product (has no commercial beverage value).
0 points: no difference in flavor from the control 1 point: a change in flavor is observed but is small and does not impair commercial value 2 points: a change in flavor is felt that impairs commercial value 3 points: a drastic change in flavor is observed and commercial value is significantly impaired Each panel also ranked each beverage in order of how favorable they felt the flavor was. The results are shown in Table 5.

The results in Table 5 show that when used at a concentration effective in inhibiting yeast growth, compound 1 has less of an effect on the flavor of beverages than sodium benzoate, an existing synthetic preservative.

Claims

Formulas 1 to 6 below:
A food or drink comprising one or more compounds represented by the formula:
The food or drink according to claim 1, which is a beverage.
Formulas 1 to 6 below:
An antibacterial agent comprising one or more compounds represented by the following formula (I):
The antibacterial agent according to claim 3, which is an antibacterial agent for food and beverages.
The antibacterial agent according to claim 3 or 4 for inhibiting the growth of one or more microorganisms of the genus Brettanomyces, Saccharomyces, Zygosaccharomyces, Neosartorya, or Alicyclobacillus.
The method for producing the food or drink according to claim 1 or 2, which comprises adding one or more compounds represented by formulas 1 to 6 or salts thereof.
Formula 2 below:
A compound represented by the formula:
Formula 3 below:
A compound represented by the formula: