JP7333089B2 - Method for producing packaged beverage - Google Patents

Description

TECHNICAL FIELD The present invention relates to a packaged beverage containing a koji extract and a method for preserving the koji extract.

In recent years, the value of traditional Japanese koji-fermented foods such as sake, shochu, amazake, miso, and soy sauce using koji has been recognized again, and the popularity of koji has increased. Koji is produced by steaming rice, rice bran, barley, beans, or the like to propagate koji mold. For example, rice grown with koji mold is called rice koji. Aspergillus oryzae is known to have the ability to produce a wide variety of enzymes that enable the production of fermented foods. The inventor of the present application is proceeding with the development of applications based on the above. Patent Document 1 reports that a feed obtained by fermenting cereals with Aspergillus oryzae promotes the growth of animals. Patent Document 2 describes a koji-fermented composition obtained by inoculating and culturing tea leaves with Aspergillus oryzae. has been reported to have antioxidant activity.

In this way, aspergillus oryzae and fermented product of aspergillus oryzae, which has various effects and promotes health, can be ingested. Koji extract is currently attracting attention. Koji water is generally obtained by pouring water into a container containing koji such as rice koji or barley koji and extracting it for a certain period of time. In addition to the koji mold itself, this koji water contains various ingredients such as enzymes produced by the koji mold and vitamins, amino acids, glucose, and polyphenols extracted from rice koji, but the taste is not much different from water. can be used as a substitute for water.

Patent No. 6111416 WO2015/119036

It is expected to provide a packaged beverage containing the koji extract so that the above-mentioned koji extract can be easily drunk on a daily basis. Therefore, when the inventors of the present application conducted research on packaged beverages containing koji extract, the water-containing solvent extract of koji deteriorated with the passage of time, generating an odor resembling old incense. I found that there is a problem that Old incense is an oxidized and deteriorated unpleasant smell that occurs during the storage and distribution process of sake, and is a compound incense composed of multiple compounds. Therefore, a beverage containing a koji extract cannot be prepared in advance, and it has been difficult to provide it as a packaged beverage that requires storage and distribution processes.

In addition, as mentioned above, the koji extract contains various enzymes produced by the koji mold, but these enzymes are extremely unstable, and their enzymatic activity decreases with the passage of time in the extract. be lost. Therefore, there is a problem that it is difficult to store the koji extract for a long period of time while maintaining the enzymatic activity.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a packaged beverage containing a koji extract in which the generation of stale aroma is suppressed and enzymatic activity is maintained.

Another object of the present invention is to provide a method for preserving a koji extract, that is, a method for suppressing the generation of stale aroma of a koji extract and a method for maintaining the enzymatic activity of the koji extract.

In order to solve the above problems, the packaged beverage of the present invention contains a koji extract and has a carbon dioxide gas internal pressure of 0.03 MPa or higher at 20°C.

By setting the carbon dioxide gas internal pressure at 20° C. in the packaged beverage to 0.03 MPa or more, generation of stale aroma from the koji extract is suppressed. In addition, the activities of enzymes derived from the koji extract, such as protease and glucoamylase, are stably maintained. Therefore, the beverage containing the koji extract can be provided as a packaged beverage that requires storage and distribution processes. The carbon dioxide gas internal pressure in this specification refers to the carbon dioxide gas pressure in the container, which can be measured by a commercially available gas pressure measuring device (gas volume measuring device) or the like.

It is also preferable that the koji extract of the packaged beverage of the present invention is a water-containing solvent extract of at least one kind of koji selected from the group consisting of rice koji, barley koji and tea koji. In this way, suitable raw materials for the water-containing solvent extract of koji are selected.

Moreover, it is also preferable that the above-mentioned packaged beverage is an alcoholic beverage further containing alcohol. The active ingredient contained in the koji extract provides an alcoholic carbonated beverage that contributes to health improvement and promotes alcohol metabolism.

Further, the method for preserving the koji extract of the present invention includes the step of adding carbon dioxide to the koji extract so that the internal pressure of the koji at 20° C. is 0.03 MPa or higher. This suppresses the generation of stale fragrance from the koji extract, and stably maintains the activity of enzymes such as protease and glucoamylase contained in the koji extract, so the koji does not deteriorate even if it is made for a while. An extract is obtained.

In addition, the method for suppressing the stale aroma of the koji extract of the present invention includes the step of adding carbon dioxide to the koji extract so that the internal pressure of carbon dioxide at 20° C. is 0.03 MPa or higher. As a result, even after storage for at least 10 days in a temperature environment of 25° C., generation of stale aroma from the koji extract is suppressed.

In addition, the method for maintaining the enzymatic activity of the koji extract of the present invention includes the step of adding carbon dioxide gas or nitrogen gas to the koji extract so that the internal pressure of the carbon dioxide gas or nitrogen gas at 20° C. is 0.03 MPa or more. have This allows the enzymatic activity to remain even after storage for at least 30 days in a temperature environment of 30°C.

Furthermore, in the method for maintaining the enzymatic activity of the koji extract of the present invention, the internal pressure of the carbon dioxide gas or nitrogen gas is preferably 0.1 MPa to 0.15 MPa. As a result, at least 65% of the initial enzymatic activity is maintained even after storage for at least 30 days in a temperature environment of 30°C.

According to the present invention, it is possible to provide a container-packaged beverage and a method for preserving a koji extract having the following excellent effects.
(1) It is possible to suppress the generation of old incense from the koji extract.
(2) The activity of the koji-derived enzyme contained in the koji extract can be maintained.
(3) Since only carbon dioxide gas is contained, the taste does not change and the efficacy of the active ingredients contained in the koji extract is not affected.
(4) Since it is a carbonated beverage, it has a refreshing taste.

Graphs showing the relationship between the time course of the enzyme titer contained in the rice koji extract by white koji mold and the internal pressure of carbon dioxide gas in Example 3: (a) a graph related to acidic proteases; amylase and α-glucosidase). Graphs showing the relationship between changes over time in the enzyme titer contained in the rice koji extract by Aspergillus aspergillus in Example 3 and the internal pressure of carbon dioxide gas: (a) a graph relating to acidic protease; amylase and α-glucosidase). Graphs showing changes in enzymatic titer over time when the rice koji extract from white koji mold was stored at a carbon dioxide gas internal pressure of 0.1 MPa in Example 4, showing (a) a graph relating to acidic protease, (b) saccharifying power (glucose amylase and α-glucosidase) and (c) xylanase. Graphs showing changes in enzymatic titer over time when the rice koji extract from Aspergillus aspergillus in Example 4 was stored at a carbon dioxide gas internal pressure of 0.1 MPa, showing (a) a graph relating to acidic protease, (b) saccharifying power (glucose amylase and α-glucosidase) and (c) xylanase.

The present invention will be described in detail below.

The koji extract in the present invention refers to an extract obtained by immersing koji in a water-containing solvent. Koji is steamed from plant raw materials such as rice, barley, tea leaves, rice bran, and beans to propagate koji mold. It is a thing. Among them, the koji used in the present embodiment includes rice koji (steamed rice to propagate koji mold), barley koji (steamed barley to propagate koji mold), and tea koji (steamed tea leaves to propagate koji mold). bred) is preferably used. Koji made from cereals such as rice koji and barley koji has been produced conventionally, and can be produced by a known method. The tea koji is a koji developed by the inventor of the present application, and can be produced by the method described in Patent Document 2, for example. Specifically, there is no particular limitation, but water is added to the raw tea leaves so that the water content of the raw tea leaves becomes about 50%, and after being subjected to water absorption treatment, it is placed in a drum-type koji making apparatus and steamed (at 95 ° C. After cooling to 30° C., koji starter (2 billion spores/1 g koji starter) of koji mold such as Kawachi black koji mold is added to the tea leaves and mixed. and koji-making in a drum-type koji-making apparatus for 3 days.

In the present invention, the type of koji mold propagated in koji is not limited, and any koji mold commonly used in the field of koji fermented foods can be used. used. Among these, white koji mold refers to a group of molds of the genus Aspergillus that form white ocher conidia (a type of asexual spores) used in the production of shochu. , Aspergillus kawachii (Aspergillus kawachii). Black koji mold refers to a group of fungi belonging to the genus Aspergillus that form black or dark brown conidia and are used in the production of distilled liquor such as awamori in Okinawa and sweet potato shochu in Kagoshima. Specifically, but not limited to, Aspergillus awamori var kawachi (Kawachi black koji mold: Aspergillus awamori var. kawachii), Aspergillus luchuensis, Aspergillus awamori, Aspergillus saitoi, Aspergillus inui , Aspergillus usami, Aspergillus aures and the like. Furthermore, yellow koji mold refers to a group of fungi of the genus Aspergillus that form yellow or yellow-green conidia that are mainly used in the production of sake, miso, soy sauce, etc. Examples include Aspergillus oryzae and Aspergillus sojae.

The koji extract is obtained by immersing the above koji in a water-containing solvent, but in the present invention, it is extracted by adding 1 g to 500 g of koji to 1000 mL of the water-containing solvent. If the amount of koji is too large, the aroma of the koji itself may be felt strongly. In addition, the water-containing solvent in the present invention means a solvent containing at least water, preferably a solvent mainly composed of water. It also includes things that are. Although not particularly limited, water containing tea (tea leaf extract such as green tea), distilled or brewed alcohol, ethanol or other alcohols, fruit juices, vitamins, inorganic salts or sugars may be used as the water-containing solvent. good.

The extraction time for producing the koji extract varies depending on the extraction temperature. , more preferably extracted for about 2 hours to 3 days, and even more preferably extracted for about 3 hours to 12 hours. Regarding the extraction temperature, in order not to lose the activity of active ingredients such as enzymes contained in koji, it is more preferable that the temperature is higher than 0°C and lower than 40°C. It is more preferable that it is extracted at ℃ or less.

In addition, in the extraction step described above, fermentation by koji mold may be performed in a water-containing solvent. Although it is not particularly limited, as an example, water containing green tea extract as a water-containing solvent (so-called green tea beverage) is added to rice koji of Kawachi white koji mold, and the rice is soaked in a temperature environment of 10 to 20 ° C. for about 3 days. Fermentation by rice koji occurs when koji is soaked and extracted. Through this extraction and fermentation process, the aroma of the green tea beverage is lost, but polyphenols derived from green tea remain in the koji extract, so that a koji extract with a refreshing sourness and richness can be obtained.

When collecting the koji extract after the extraction treatment, it is preferable to perform a filtration treatment to separate the soaked koji from the koji extract. Moreover, in order to remove microorganisms such as Aspergillus oryzae from the collected koji extract, it is more preferable to perform a sterile filtration treatment. This eliminates the need for high-temperature sterilization, so that the components extracted from the koji are contained in the koji extract without being denatured or degraded. It is of course possible to carry out the aseptic filtration treatment after injecting the gas into the koji extract.

In the present invention, the internal carbon dioxide pressure of the koji extract or the beverage containing the koji extract is adjusted to 0.03 MPa or higher at 20°C. As a result, generation of stale aroma from the koji extract can be suppressed. The carbon dioxide gas internal pressure refers to the carbon dioxide gas pressure in the container, and can be measured using a commercially available gas pressure measuring device (gas volume measuring device) or the like. The carbon dioxide internal pressure is preferably adjusted to 0.03 MPa or higher, more preferably 0.05 MPa or higher. As a method for adjusting the internal pressure of carbon dioxide gas, that is, a method for adding carbon dioxide gas to koji extract or a beverage containing koji extract, the internal pressure of carbon dioxide gas can be adjusted using any known method or a known carbonator. It is possible and not particularly limited. One example is a method of pressurizing and dissolving carbon dioxide gas in a koji extract or the like using a carbonated water maker. It is also possible to adjust the internal carbon dioxide pressure by mixing

Further, in the present invention, the carbon dioxide gas internal pressure of the koji extract or the beverage containing the koji extract is adjusted to 0.03 MPa or more at 20° C., The activity of the koji-derived enzyme contained in the koji extract can be maintained. Specifically, the enzymatic activity contained in the koji extract can remain even after storage for at least 30 days in a temperature environment of 30°C. The carbon dioxide gas internal pressure is preferably adjusted to 0.03 MPa or more, more preferably 0.1 MPa to 0.15 MPa or less, from the viewpoint of the residual effect of enzyme activity. . Further, even if nitrogen gas is used in place of the carbon dioxide gas described above, the same effect of maintaining enzyme activity can be obtained.

In the present invention, the enzyme whose activity is maintained in the koji extract or the beverage containing the koji extract is an enzyme derived from koji mold or koji mold, and is not particularly limited, and includes α-amylase, α-glucosidase, Examples include β-glucosidase, glucoamylase, a group of enzymes exhibiting saccharifying power (glucoamylase + α-glucosidase), hemicellulase such as acidic protease, acidic carboxypeptidase, xylanase, cellulase, and lipase.

In addition, the beverage containing the koji extract in which the carbon dioxide gas internal pressure is adjusted may contain components other than the koji extract. Examples of other ingredients include, but are not limited to, sweeteners such as sugars, acidulants, fruit juices, plant extracts, tea extracts, milk components, flavors, vitamins and coloring agents. After these other components are blended with the koji extract, the internal carbon dioxide gas pressure is adjusted to 0.03 MPa or more at 20° C. as described above, so that the koji extract is included. It is possible to suppress the generation of stale aroma from the beverage, and stably maintain the activity of the enzyme contained in the koji extract.

In addition, alcohol may be contained in the beverage containing the koji extract in which the carbon dioxide gas internal pressure is adjusted. As the alcohol, both distilled liquor and brewed liquor can be used, and there is no particular limitation, but shochu such as potato shochu and awamori, refined sake, raw material alcohol, gin, whiskey, brandy, spirits, and the like can be used. After the alcohol or the like is blended with the koji extract, the internal carbon dioxide gas pressure at 20° C. is adjusted to 0.03 MPa or more as described above, thereby producing an alcoholic beverage containing the koji extract. It is possible to suppress the generation of old incense, and the activity of the enzyme contained in the koji extract is stably maintained. The alcohol content of the alcoholic beverage is not particularly limited, but if the alcohol content is adjusted to less than 10 v/v%, a refreshing highball-like koji water alcoholic beverage can be obtained.

The packaged beverage containing the koji extract of the present invention is not particularly limited as long as it is a container that can be filled and sealed.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples.

[Example 1]
1. Suppression of generation of stale aroma from koji extract by adjusting carbon dioxide gas pressure 200 g of white koji (Aspergillus kawachii) rice koji was added to 1 L of water, and extracted at 30°C for 10 hours. The supernatant was recovered and filtered aseptically to obtain a water extract of koji used in Examples and Comparative Examples below. This water extract of koji and various alcohols were mixed to obtain beverage samples (test groups A to D) shown in Table 1 below.

Carbon dioxide gas was pressurized so that the internal pressure of the carbon dioxide gas in the container at 20° C. was 0.1 MPa to the four types of beverage samples of test groups A to D shown in Table 1, and the samples were filled in 100 mL aluminum cans. The carbon dioxide gas internal pressure in the container was confirmed by measuring the gas pressure of a beverage sample that was quickly filled into a can and capped after carbonation. Four types of aluminum canned beverage samples with an internal carbon dioxide gas pressure adjusted to 0.1 MPa were allowed to stand in an environment of 25°C. Or sensory evaluation was performed for the old scent-like odor. The sensory evaluation was conducted by 10 panelists who are familiar with old incense and old incense-like odors and who are engaged in sake brewing at a sake brewery. The reason for sensory evaluation is that although various components of old incense have been identified, old incense is a complex odor that is a mixture of various components, and the components have not yet been clearly determined. , and sensory evaluation by the human sense of smell. Table 2 shows the details of the 10 panelists, and Table 3 shows the sensory evaluation results.

As shown in Table 3, no stale flavor was observed in any of the canned beverages containing the water extract of koji.

[Comparative example]
2. Occurrence of Old Incense from Koji Extract A water extract of koji produced in the same manner as in Example 1 was used, and this water extract of koji was mixed with various alcohols to produce beverage samples (shown in Table 4 below). Control plots AD) were obtained.

Four types of beverage samples of control groups A to D shown in Table 4 were directly filled into 100 mL aluminum cans. Four types of aluminum canned beverage samples were allowed to stand in an environment of 25°C, and sensory evaluation was performed for stale odor or stale scent-like odor generated from the beverage containing the water extract of koji rice every day for 10 days. Same as 1. The same persons as in Example 1 were in charge of the 10 panelists. Table 5 shows the results of sensory evaluation.

As shown in Table 5, it was confirmed that the canned beverages containing the aqueous koji extract developed stale aroma after 3 days, and the beverage sample containing the aqueous koji extract alone (control D) After 4 days, 50% of the panelists evaluated that a stale scent was generated, and after 6 days, all of the panelists (100%) evaluated that a stale scent was generated. In addition, the beverage samples containing alcohol (control groups A to C) were also confirmed to have the same stale flavor as the alcohol-free beverage sample (control group D). In addition, although the water extract of koji has anti-oxidant activity derived from koji, the old scent is generated in this way, so it is considered that the old scent is not necessarily generated by oxidation. Ta.

[Example 2]
3. Examination of carbon dioxide pressure A water extract of koji was produced in the same manner as in Example 1, and the same beverage samples as those shown in Table 1 (test groups A to D) were obtained. For the four types of beverage samples of test groups A to D shown in Table 1, the carbon dioxide gas internal pressure in the container at 20 ° C. was 0.01 MPa, 0.03 MPa, 0.05 MPa, 0.1 MPa or 0.2 MPa. Carbon dioxide gas was pressurized into each, and filled in a 100 mL aluminum can. The carbon dioxide gas internal pressure in the container was confirmed by measuring the gas pressure of a beverage sample that was quickly filled into a can and capped after carbonation. Four types of aluminum-canned beverage samples each adjusted to have a predetermined carbon dioxide gas internal pressure were allowed to stand in an environment of 25° C. for 10 days. After 10 days, sensory evaluation was performed in the same manner as in Example 1 and Comparative Example for the stale scent or stale scent-like odor generated from the beverage containing the water extract of koji. The 10 panelists were the same persons as in Example 1 and Comparative Example. Table 6 shows the results of sensory evaluation.

As shown in Table 6, when the carbon dioxide gas internal pressure was 0.01 MPa, the canned beverage containing the water extract of koji was confirmed to have a stale aroma. The occurrence of old incense was not confirmed. From this, it was found that by adjusting the carbon dioxide gas internal pressure to 0.03 MPa or more, the generation of stale aroma from the beverage containing the water extract of koji can be suppressed, and the beverage can be stored for a long period of time in a drinkable state.

[Example 3]
4. Effect of maintaining enzyme activity contained in koji extract by adjusting carbon dioxide gas pressure (1)
30 g of rice koji obtained by propagating white koji mold (Aspergillus kawachii) on rice was added to 100 mL of water, and extracted at 30° C. for 3 hours. The supernatant was recovered and sterile-filtered through a sterilizing filter to obtain an aqueous extract of koji. The enzymatic titers of acidic protease and saccharifying power (glucoamylase + α-glucosidase) contained in the just-obtained koji extract were measured as enzymatic activities on the 0th day. Carbon dioxide gas was pressurized into the water extract of koji so that the internal pressure of carbon dioxide gas in the container at 20° C. was 0.1 MPa, and the mixture was filled in a 100 mL aluminum can to prepare a test sample. The carbon dioxide gas internal pressure in the container was confirmed by measuring the gas pressure of the koji extract, which was immediately filled into a can and capped after carbonation. Furthermore, carbon dioxide gas was injected into the water extract of koji obtained in the same manner so that the internal pressure of carbon dioxide gas in the container at 20 ° C. was 0.15 MPa, 0.2 MPa, and 0.25 MPa, respectively. A test sample was prepared by filling an aluminum can. Furthermore, for comparison, a control sample was prepared by filling a 100 mL aluminum can with the water extract of koji obtained in the same manner as it was (internal carbon dioxide gas pressure: 0 MPa). Five types of aluminum canned samples each adjusted to have a predetermined carbon dioxide gas internal pressure were allowed to stand in an environment of 30° C. for 30 days. After 30 days, the aluminum can was opened, and the enzymatic titers of acidic protease and saccharifying activity contained in the water extract of koji were measured as enzymatic activities on the 30th day. The results are shown in Tables 7, 8 and FIG.

The enzymatic titers of acid protease and saccharifying activity (glucoamylase + α-glucosidase) were measured according to the standard analytical method of the National Research Institute of Brewing (Solid Koji; National Research Institute of Brewing).

As the rice malt, the water extract of the rice malt obtained by propagating Aspergillus oryzae in rice was also subjected to the same conditions and methods as described above to improve the enzymatic activity of acidic protease and saccharification. I made a measurement. The results are shown in Tables 9, 10 and FIG.

As shown in FIGS. 1 and 2 and Tables 7 to 10, the water extract of koji into which carbon dioxide gas was injected showed various enzymatic activities even after being stored in an environment of 30° C. for 30 days. It was confirmed that According to this result, by injecting carbon dioxide gas into the water extract of koji so that the internal pressure of carbon dioxide gas at 20°C becomes 0.1 to 0.25 MPa, even after storage at 30°C for 30 days, , at least more than 60% of the enzyme titer can be maintained. At this time, the enzymatic activity was completely lost in the water extract of koji to which carbon dioxide gas was not injected, which was a comparative control. Moreover, according to these results, it was found that the enzymatic titer tends to decrease slightly as the internal pressure of carbon dioxide becomes higher than a predetermined pressure. For this reason, the internal pressure of the water extract of koji is preferably adjusted to 0.1 MPa to 0.15 MPa in order to maintain the enzymatic activity. It was shown that the enzyme titer of at least 66% or more of the initial enzyme activity was maintained even after the treatment. In addition, in this example, carbon dioxide gas was injected into the water extract of koji, but it has been confirmed that the same effect of maintaining enzyme activity can be obtained by using nitrogen gas instead of carbon dioxide gas. .

[Example 4]
5. Effect of maintaining enzyme activity contained in koji extract by adjusting carbon dioxide gas pressure (2)
30 g of rice koji obtained by propagating white koji mold (Aspergillus kawachii) on rice was added to 100 mL of water, and extracted at 30° C. for 3 hours. The supernatant was recovered and sterile-filtered through a sterilizing filter to obtain an aqueous extract of koji. The enzymatic titers of acidic protease, saccharifying power (glucoamylase + α-glucosidase) and xylanase contained in the just-obtained koji extract were measured as enzymatic activities on the 0th day. A test sample was prepared by injecting carbon dioxide gas into the water extract of this koji so that the carbon dioxide gas internal pressure in the container at 20° C. was 0.1 MPa, and filling it in a 100 mL aluminum can (carbon dioxide gas internal pressure 0 .1 MPa). The internal pressure of carbon dioxide gas in the container was confirmed by measuring the gas pressure of the water extract of koji that was immediately filled into a can and capped after carbonation. Furthermore, for comparison, a control sample was prepared by filling a 100 mL aluminum can with the water extract of koji obtained in the same manner as it was (internal carbon dioxide gas pressure: 0 MPa). These aluminum canned samples were allowed to stand in a 4° C. environment for 30 days, 60 days, 90 days and 120 days. On each elapsed day, the aluminum can was opened, and the enzymatic titers of acidic protease, saccharifying power and xylanase contained in the water extract of koji were measured. The results are shown in Table 11 and FIG.

The enzymatic titers of acid protease and saccharifying activity (glucoamylase + α-glucosidase) were measured according to the standard analytical method of the National Research Institute of Brewing (Solid Koji; National Research Institute of Brewing). The enzymatic titer of xylanase (activity to hydrolyze the β1,4-glycosidic bond of xylan) was measured by the Somogyi-Nelson method. and the enzyme titer was determined. Specifically, a standard solution containing 0 to 240 μL/mL of xylose was prepared, 0.5 mL of the standard solution was developed by the Somogyi-Nelson method, and a standard curve was created from the absorbance at 500 nm. On the other hand, 0.4 mL of a 1% xylan solution as a substrate was added to 0.1 mL of the water extract of the koji of the present invention, and the mixture was reacted at 40°C for 60 minutes. Color was developed, absorbance at 500 nm was determined, and free xylose concentration X (mg/tube) was determined from a standard curve. From this free xylose concentration X, the enzyme titer of xylanase was obtained by calculating the free xylose concentration per 1 g of koji to be extracted.

As the rice koji, the water extract of the koji obtained by propagating yellow koji mold (Aspergillus oryzae) in rice was also used to measure the enzyme titers under the same conditions and methods as described above. . The results are shown in Table 12 and FIG.

As shown in FIGS. 3 and 4 and Tables 11 and 12, the water extract of koji into which carbon dioxide gas was forced to 0.1 MPa was preserved in an environment of 4° C. for 120 days. It was confirmed that the enzyme remained in the water extract of koji with an enzyme titer of more than 90%. At this time, the enzymatic activity of the water extract of koji to which carbon dioxide gas was not injected, which was used as a comparison control, disappeared after 30 days even when the sample was stored at a temperature of 4°C. , the enzyme titer was zero. In this example, carbon dioxide gas was injected into the water extract of koji, but it has been confirmed that the same effect of maintaining enzyme activity can be obtained by using nitrogen gas instead of carbon dioxide gas. .

The present invention is not limited to the above-described embodiments or examples, and includes various design changes within the scope of the invention within the scope of the invention described in the claims. .

Claims (3)

an extraction step of immersing koji in a water-containing solvent to obtain a koji extract;
The step of adding carbon dioxide to the koji extract or the beverage containing the koji extract so that the internal pressure of carbon dioxide gas at 20° C. is 0.1 MPa to 0.15 MPa, and aseptic filtration without heat sterilization. A method for producing a packaged beverage containing a koji extract in which generation of stale aroma is suppressed and enzymatic activity is maintained, characterized by comprising the steps of: 2. The method for producing a packaged beverage according to claim 1 , wherein the koji in the extraction step is at least one kind of koji selected from the group consisting of rice koji, barley koji and tea koji. 3. The method for producing a packaged beverage according to claim 1, wherein the water-containing solvent in the extraction step is water or a green tea beverage.

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