JP2023157076A - Production method of broth - Google Patents

Abstract

To provide a production method of broth, capable of shortening an extraction time even in the case of extracting at a low-temperature, and producing broth in which flavor component is more extracted without increasing miscellaneous taste.SOLUTION: A production method of broth includes extracting flavor component by immersing a broth raw material in a liquid at 40°C or less. In the production method of broth, an immersion liquid obtained by immersing a broth raw material in a liquid is irradiated with microwaves for a fixed time so as to extract flavor component in a short time at a high efficiency compared to the case of no irradiation of microwaves.SELECTED DRAWING: Figure 1

Description

Application for application of Article 30, Paragraph 2 of the Patent Act filed on December 7, 2021 at http://agingbooster. com/lab/02/index. Published in html

TECHNICAL FIELD The present invention relates to a method for producing soup stock, which comprises producing soup stock by irradiating a stock raw material with microwaves.

BACKGROUND ART Conventionally, methods for producing soup stock with reduced taste have been disclosed. For example, by extracting the soup stock raw material with hot water of 60°C or higher and concentrating the extract to 1.1 times or more, and quickly cooling the concentrated extract to 20°C or lower, the aftertaste becomes more delicious without increasing the astringency. An excellent method for producing soup stock has been disclosed (see Patent Document 1). Furthermore, a method has been disclosed in which kelp stock is extracted with cold water by immersing kelp in a solvent at 0 to 20°C and extracting for 10 to 30 hours (see Patent Document 2).
In addition, the applicant has disclosed a microwave ripening method that can improve the ripeness of food and shorten the ripening period by irradiating the food with microwaves to age the food (patented). (See Reference 3).

JP2019-208394A Patent No. 6570193 Japanese Patent Application Publication No. 2020-182456

As in Patent Document 1, when the stock raw material is heated with hot water of 60° C. or higher, there is a problem that components other than umami components such as miscellaneous taste and bitterness are also eluted. Further, when extracting flavor components using water or the like at a low temperature as in Patent Document 2, there are problems in that extraction takes a long time and the soup stock is spoiled by microorganisms.
Furthermore, there has been a desire for an extraction method that can more efficiently extract flavor components from stock raw materials.
Under these circumstances, the inventor considered an unprecedented method of producing soup stock by applying microwave aging technology as shown in Patent Document 3, and after intensive research, created the present invention. .

The present invention provides a soup stock that can shorten the extraction time even when extracting umami components from stock raw materials at low temperatures, and can produce a soup with more umami components extracted without increasing unpleasant taste. The purpose is to provide a manufacturing method for.

The gist of the present invention is the method for producing soup stock described in (1) to (9) below.
(1) In a method for producing dashi stock in which the flavor components are extracted by immersing the dashi raw material in a liquid at 40°C or lower, the dipping liquid in which the dashi raw material is immersed in the liquid is irradiated with microwaves for a certain period of time. A method for producing dashi stock that is characterized by extracting flavor components in a shorter time and with higher efficiency than when irradiating waves is not used.
(2) The method for producing soup stock according to (1) above, wherein the immersion liquid is cooled at the same time as the microwave irradiation is performed so that the external temperature of the immersion liquid is lower than the internal temperature of the immersion liquid. .
(3) Production of the soup stock according to (1) or (2) above, wherein the microwave is irradiated so that the internal temperature of the immersion liquid is higher than 0°C and lower than 25°C. Method.
(4) Production of the soup stock according to (1) or (2) above, wherein the microwave irradiation is performed such that the external temperature of the dipping liquid is in a range of -5°C or higher and lower than 20°C. Method.
(5) At the same time as irradiating the microwave, the immersion liquid is cooled so that the difference between the internal temperature and the external temperature of the immersion liquid is higher than 5°C and lower than 20°C. , the method for producing soup stock according to (2) above.
(6) The method for producing soup stock according to (1) or (2) above, wherein the microwave irradiation is performed for 30 minutes or more and 4 hours or less.
(7) The method for producing dashi soup according to (1) or (2) above, wherein the soup stock raw material is a combination of kelp, knotweed, or dried sardines.
(8) Production of the soup stock according to (7) above, wherein the ratio of the knots or dried sardines to kelp in the stock raw materials (weight of the knots or dried sardines/weight of kelp) is less than 2. Method.
(9) The method for producing dashi soup according to (1) or (2) above, wherein microwaves are irradiated for a certain period of time to an immersion liquid in which the soup stock raw material prepared by adding an umami seasoning to kelp is immersed in the liquid.

According to the present invention, by irradiating microwaves for a certain period of time to the dipping liquid in which the dashi raw material is immersed, even when extracting flavor components from the dashi raw material at low temperatures, the extraction time can be shortened, and the extraction time can be reduced. It is possible to produce soup stock with more umami components extracted without increasing the taste.

FIG. 1 is a configuration diagram of a microwave aging device according to an embodiment. It is a table showing the relationship between the extraction conditions of soup stock and the concentrations of inosinic acid and glutamic acid in this example. 3 is a graph showing a light absorption spectrum measured in Example 1. 3 is a graph showing a light absorption spectrum measured in Example 2. 3 is a graph showing a light absorption spectrum measured in Example 3. 3 is a graph showing a light absorption spectrum measured in Example 4. 3 is a graph showing a light absorption spectrum measured in Example 5. 7 is a graph showing light absorption spectra measured in Examples 7 and 9. 3 is a graph showing a light absorption spectrum measured in Example 10.

(Foods subject to ripening)
In the present invention, when extracting the flavor components from the dashi raw materials by immersing them in a liquid such as water, the umami components are extracted from the dashi raw materials by irradiating the dipping liquid in which the dashi raw materials are immersed with microwaves for a certain period of time. This is a method for producing dashi that allows for more efficient extraction at low temperatures and in a short time. Dashi ingredients are not particularly limited as long as they are commonly used ingredients, but include ingredients rich in glutamic acid such as kelp, ingredients rich in inosinic acid such as dried dried dried fish, dried sardines, or guanyl such as shiitake mushrooms. Examples include foods rich in acid. As a stock ingredient, kelp, knots, or dried sardines may be used alone, but the structure is not limited to this, and kelp, knots, and/or dried sardines may be used in combination. Good too. Similarly, shiitake mushrooms may be used alone, but the structure is not limited to this, and shiitake mushrooms may be used in combination with kelp, and/or joints and/or dried sardines.

(Dashi soup manufacturing method)
Conventionally, when extracting flavor components from dashi ingredients to make dashi, there are two methods: boiling the dashi ingredients in boiling water to boil out the flavor components, and adding the dashi ingredients to relatively low-temperature water (room temperature water or cold water below room temperature). There is a method of soaking for a long time to extract the flavor components. The method of boiling stock ingredients in boiling water to extract umami components has the problem that in addition to the umami components, miscellaneous tastes such as bitterness and astringency are also extracted. Furthermore, the method of extracting flavor components by immersing stock ingredients in relatively low-temperature water has the problem that it takes a long time to extract the stock, and that the stock is easily spoiled by the growth of microorganisms.

The present invention is based on the inventor's discovery that by irradiating microwaves for a certain period of time to the immersion liquid in which the stock ingredients are soaked, it is possible to efficiently extract the stock in a short time even at a relatively low temperature. It has been completed. In addition, by irradiating the dipping liquid with microwaves to extract the umami components, the inventors have discovered that by extracting the umami components without irradiating the dipping liquid with microwaves, more umami components can be extracted without increasing the unpleasant flavor, compared to the case where the umami components are extracted without irradiating the soaking liquid with microwaves. I also discovered that it can be extracted. Hereinafter, embodiments of the method for producing soup stock of the present invention will be described.

In the microwave irradiation according to this embodiment, microwaves are irradiated for a relatively long time (30 minutes or more) to the soaking liquid placed in a container using a microwave ripening device 1 to be described later to extract flavor components from the soup stock raw material. Take the dashi stock. The wavelength of the microwave to be irradiated may be any wavelength that can dielectrically heat water molecules in the immersion liquid, and may be, for example, 2.4 to 2.5 GHz. Furthermore, in this embodiment, since the flavor components are extracted from the stock raw material at a relatively low temperature, the internal temperature of the dipping liquid (temperature of the liquid making up the dipping liquid and the stock raw material) is higher than 0°C and lower than 25°C. The intensity of the microwave irradiation is controlled within a range, more preferably within a range of 5°C or higher and 20°C or lower. In addition, as will be described later, in the microwave aging apparatus 1 according to the present embodiment, the interior of the refrigerator in which the immersion liquid is left can be cooled, and the external temperature (inside temperature) of the immersion liquid during microwave irradiation is controlled. is lower than the internal temperature of the immersion liquid, preferably the external temperature of the immersion liquid is within a range of -5°C or higher and lower than 20°C, more preferably the external temperature of the immersion liquid is 0. The inside of the refrigerator is cooled to a temperature of 10° C. or higher and 10° C. or lower, and the flavor components are extracted in this environment. Particularly, in this embodiment, the temperature difference between the internal temperature and the external temperature of the immersion liquid is higher than 5°C and lower than 20°C, more preferably 10°C or higher and 15°C or lower. The immersion liquid is heated by wave irradiation and the inside of the refrigerator is cooled. Moreover, in this embodiment, microwave irradiation is performed for a longer time than normal hot water extraction and for a shorter time than normal cold water extraction. Specifically, microwave irradiation is performed for 30 minutes or more and 4 hours or less, more preferably 1 hour or more and 2 hours or less, to extract the flavor components. The amount of the stock raw material to be used is not particularly limited, but it is desirable that the ratio of sardine to kelp (weight of sardine/weight of kelp) is less than 2, more preferably less than 1.7.

(Microwave ripening device)
FIG. 1 is a configuration diagram of a microwave aging apparatus 1 according to this embodiment. The microwave aging device 1 according to this embodiment includes a cooling section 10, a microwave oscillation section 20, a microwave aging section 30, a control section 50, and a UV lamp 60, as shown in FIG. The microwave aging device 1 includes a microwave aging section 30 inside the cooling section 10. The microwave aging device 1 according to the present embodiment not only produces soup stock, but also produces meat such as beef (including processed meat products such as ham), seafood, dairy products such as cheese, edamame (soybeans), and coffee. It is also possible to age legumes such as beans, vegetables, fruits, noodles, breads, alcoholic beverages such as wine, fermented foods (including fermented seasonings such as miso and soy sauce), etc.

The cooling unit 10 is a device that cools the internal space of the cooling unit 10. As shown in FIG. 1, the cooling unit 10 includes a cooler 11, a first fan 12, a cooling chamber 13, and a cooling chamber door 14 (not shown). In this embodiment, the cooler 11 generates cold air by exchanging heat with the outside, and the first fan 12 blows the generated cold air into the cooling chamber 13 inside the cooling unit 10 . Thereby, the inside of the cooling chamber 13 can be kept at a low temperature. As will be described later, in this embodiment, the control unit 50 controls the microwave oscillation unit so that the external temperature (temperature inside the refrigerator) of the dipping liquid is lower than the internal temperature of the dipping liquid in which the stock ingredients are immersed. The operation of the cooling chamber 20 and the temperature inside the cooling chamber 13 are appropriately controlled. Furthermore, by opening the cooling chamber door 14, the user can take the immersion liquid contained in the container into and out of the microwave aging section 30 installed in the cooling chamber 13.

The microwave oscillator 20 oscillates microwaves to irradiate the immersion liquid placed in the container. Although an oscillator using a magnetron can be used as the microwave oscillator 20, in this embodiment, a solid-state oscillator using a semiconductor element is used, which can obtain higher frequency and output stability than a magnetron. . The microwave oscillation unit 20 oscillates microwaves by continuously changing the frequency between 2.4 and 2.5 GHz. The microwave oscillated by the microwave oscillation section 20 is irradiated from the irradiation port 31 of the microwave aging section 30 via the cable 21. Note that by continuously changing the frequency of the microwave between 2.4 and 2.5 GHz, the distribution of the electromagnetic field in the microwave aging section 30 is made uniform, so the immersion liquid also has a uniform distribution. Microwave irradiation can promote the extraction of flavor components by uniformly heating the dipping liquid.

As shown in FIG. 1, the microwave ripening section 30 includes an irradiation port 31, a second fan 32, a ripening chamber 33, and a ripening chamber door 34 (not shown). By opening the ripening chamber door 34, the user can take the immersion liquid contained in the container into and out of the ripening chamber 33.

The ripening chamber 33 is a cavity in which reflective plates for reflecting microwaves are installed on all inner surfaces (inner walls). An irradiation port 31 is installed on the inner surface of the ripening chamber 33 to irradiate the inside of the ripening chamber 33 with microwaves oscillated by the microwave oscillator 20 . In this embodiment, a small, high-gain patch antenna (planar antenna) is attached to the irradiation port 31, and thereby the microwave oscillated by the microwave oscillation unit 20 is irradiated into the ripening chamber 33. The aging chamber 33 may be provided with shelves of any shape made of a microwave transparent material such as Teflon (registered trademark) or polypropylene. Further, when using a metal material such as stainless steel, a grid-like shelf with an interval of 20 mm or more or a punched metal-shaped shelf with an opening with a diameter of 20 mm or more may be installed.

The second fan 32 blows cold air in the cooling chamber 13 to the ripening chamber 33. In this embodiment, as shown in FIG. 1, the second fan 32 is attached to the outside of the ripening chamber 33, and the side wall of the ripening chamber 33 to which the second fan 32 is attached has a first minute opening 35. It is provided. The first minute aperture 35 has a size shorter than the wavelength of the microwave. For example, in this embodiment, the first minute aperture 35 has a diameter of 10 mm or less. The microwave irradiated into the ripening chamber 33 is blocked by the first minute opening 35, and only the cold air blown by the second fan 32 passes through. Further, a second micro-aperture 36 having the same diameter as the first micro-aperture 35 is provided on the side wall of the ripening chamber 33 facing the first micro-aperture 35 . Although the microwave irradiated to the ripening chamber 33 is blocked by the second minute opening 36, the air inside the ripening chamber 33, which has been warmed by heat exchange with the immersion liquid, passes through the second minute opening 36. It is discharged into the cooling chamber 13. The first micro-aperture 35 and the second micro-aperture 36 may be provided in an area that occupies most of one or more side walls to improve ventilation. Furthermore, the ripening chamber 33 can be constructed using punched metal in which the first minute opening 35 and the second minute opening 36 are formed in advance, and a stainless steel plate with a diameter of 10 mm can also be used as such punched metal.

The control unit 50 has a built-in program that performs temperature control so that the external temperature and internal temperature of the immersion liquid become respective predetermined temperatures. Specifically, the control unit 50 controls the operation of the microwave oscillation unit 20, the cooler 11, the first fan 12, and the second fan 32, thereby controlling the microwave output by the microwave oscillation unit 20 and the cooler. Temperature control is performed by controlling the temperature of the cold air generated by the fan 11 and the air volume of the first fan 12 and the second fan 32. For example, the control unit 50 can increase the internal temperature of the immersion liquid by increasing the microwave output of the microwave oscillation unit 20, and can also decrease the temperature of the cold air from the cooler 11, or By increasing the air volume of the first fan 12 and the second fan 32, the external temperature of the immersion liquid can be lowered.

Further, the control unit 50 can control microwave oscillation by the microwave oscillation unit 20. For example, in addition to fixed irradiation that causes the microwave oscillation unit 20 to oscillate at a fixed output value and a constant frequency, the control unit 50 causes the microwave oscillation unit 20 to oscillate at a short period (for example, a period of several milliseconds). It is possible to perform intermittent irradiation in which irradiation and stopping are repeated, sweep irradiation in which the frequency of the microwave oscillation unit 20 is changed over time, and continuous irradiation in which the output value of the microwave oscillation unit 20 is changed over time. Further, the control unit 50 may be configured to perform microwave irradiation for at least 30 minutes or longer without needing to continuously irradiate microwaves while extracting flavor components with the immersion liquid. Furthermore, the control unit 50 switches the microwave irradiation ON and OFF at regular intervals (for example, several hours) (in the case of intermittent irradiation, the period of intermittent irradiation and the period of no intermittent irradiation are set constant). It is also possible to adopt a configuration in which the microwave oscillation unit 20 is controlled so as to switch at different times.

The control unit 50 also includes a temperature sensor that measures the internal temperature and external temperature of the immersion liquid (for example, a fluorescent optical fiber thermometer (manufactured by Anritsu Keiki Co., Ltd.) that can contact temperature measurement even in a microwave environment). , a radiation type temperature sensor that measures the intensity of infrared rays and visible light in a non-contact manner), and the temperature can be appropriately controlled based on the measurement results of the temperature sensor.

Further, the control unit 50 controls the immersion liquid at a specific wavelength (for example, 250 nm or 250 nm corresponding to nucleic acids such as inosinic acid and guanylic acid, which are flavor components) of the immersion liquid, which is obtained from a non-contact spectrophotometer installed in the ripening chamber 33. It is also possible to adopt a configuration in which the output of the microwave from the microwave oscillation unit 20, the temperature of the cold air from the cooler 11, and the air volume of the first fan 12 and the second fan 32 are controlled according to the absorbance at a wavelength of 260 nm). . In addition, the user operates the operation unit 40, which is an input device such as an operation button or a touch panel, to input information about the soup stock raw materials, such as the type (for example, kelp, knotweed, dried sardines, etc.) and size of the stock raw materials. By doing so, the control unit 50 can be configured to automatically adjust the internal temperature and external temperature of the immersion liquid.

As described above, in the microwave aging device 1 according to the present embodiment, the heating mechanism (the microwave oscillation unit 20 and the microwave aging unit 30) heats the immersion liquid, and the cooling mechanism (the cooling unit 10 and the second fan 32) By cooling the surface of the immersion liquid at the same time, it is possible to raise the internal temperature of the immersion liquid while lowering the external temperature of the immersion liquid. Specifically, the internal temperature of the immersion liquid can be higher than the external temperature of the immersion liquid. In particular, by dielectrically heating the dipping liquid using microwave irradiation, it is possible to uniformly heat the inside of the dipping liquid, thereby promoting the extraction of flavor components. Furthermore, by cooling the immersion liquid from the surface through the operation of the cooling unit 10 and the second fan 32, it is also possible to suppress the growth of bacteria on the surface of the immersion liquid.

The microwave aging device 1 according to the present embodiment includes an operating section 40 for the user to operate, and by operating the operating section 40, the user can adjust the temperature at a temperature higher than the above-mentioned soup stock extraction temperature. You can also instruct a high-temperature extraction mode to extract soup stock. When the high temperature extraction mode is instructed by the user, the control unit 50 can also set the internal temperature of the immersion liquid to a temperature exceeding 25° C., for example.

The UV lamp 60 is a device that generates ultraviolet light. In this embodiment, by irradiating the cool air circulating in the cooling chamber 13 and the ripening chamber 33 with ultraviolet rays, bacteria floating in the cold air can be sterilized, and the surface of the immersion liquid and the cooling chamber 13 and the ripening chamber 33 can be sterilized. The growth of existing bacteria can be further suppressed. Further, it is also possible to configure a part of the wall of the ripening chamber 33 (at least a part on the UV lamp 60 side) to allow ultraviolet rays to pass through, or to install the UV lamp directly in the ripening chamber 33. In that case, During extraction of the soup stock, the surface of the dipping liquid placed in the ripening chamber 33 can be directly irradiated with ultraviolet light generated by the UV lamp 60. In this way, by irradiating the surface of the dipping liquid with ultraviolet rays during extraction of the soup stock, it is possible to further suppress the growth of bacteria present on the surface of the dipping liquid. Note that the control unit 50 can also control the operation of the UV lamp 60. For example, the control unit 50 may control the UV lamp 60 to irradiate ultraviolet rays for a certain period of time (for example, several hours) from the timing when ripening is started or from the timing when the ripening chamber door 34 is closed (after opening). I can do it.

(Example)
Next, an example of the method for producing soup stock according to the present invention will be described.
In the present Examples (Examples 1 to 13), the stock ingredients were iriko (dried sardine iriko (special) large feathers from Ibuki, head and pith excluded) and/or kelp (Hidaka kelp, produced in Hokkaido, manufactured by Hirokon Foods Co., Ltd.). The umami components were extracted by irradiating the dipping liquid obtained by soaking the soup stock raw material in tap water with microwaves using the microwave aging device 1 described above.
Then, the soaking liquid (soup) from which the flavor components were extracted was stirred, filtered, and diluted, and the concentrations of glutamic acid and inosinic acid, which are flavor components, were measured in the diluted broth. The glutamic acid concentration was measured using the L-glutamic acid measurement kit "Yamasa" NEO (manufactured by Yamasa Soy Sauce Co., Ltd.), and the inosinic acid concentration was measured using HPLC equipped with a UV detector. .
In addition, in this example, in order to estimate the concentration of inosinic acid, we used the soup stock of the example in which the umami components were extracted by irradiating microwaves and the soup stock of the comparative example in which the umami components were extracted without irradiating microwaves. The absorbance was measured at a wavelength of 250 nm, which is the wavelength at which inosinic acid absorbs light.
Furthermore, in this example, the absorbance in the wavelength range of 220 to 320 nm was measured for the soup stock of the example and the soup stock of the comparative example. In addition, in this example, in order to create a highly accurate optical absorption spectrum, the absorbance was measured in the wavelength range of 220 to 320 nm using the soup stock of the example and comparative example diluted with a predetermined dilution factor. And a light absorption spectrum of a comparative example was created. The absorbance at 220 to 320 nm was measured in order to roughly determine the concentration of multiple types of nucleic acids, amino acids, water-soluble polymers, etc. eluted from the stock raw material.

FIG. 2 shows the conditions for extracting soup stock and the concentrations of extracted glutamic acid and inosinic acid in the present Examples (Examples 1 to 13). In this example, the standard extraction conditions are as follows: A soup stock material containing 4 g of irico and 4 g of kelp is soaked in 400 ml of tap water, and the internal temperature is 15°C and the external temperature is 5°C. The umami components were extracted for one hour by irradiating microwaves and cooling by the cooling unit 10 and second fan 32. In the following examples, umami components were extracted under standard extraction conditions unless otherwise specified. Note that in FIG. 2, conditions different from the standard extraction conditions are displayed in gray.

(Example 1)
In Example 1, only 4 g of kelp was soaked in 400 ml of tap water as a stock raw material, and the soaking liquid was soaked in a microtube for 1 hour so that the internal temperature of the soaking liquid was 10°C and the external temperature of the soaking liquid was 0°C. In addition to irradiating waves, cooling was performed using the cooling unit 10 and the second fan 32. In addition, as Comparative Example 1, only 4 g of kelp was immersed in 400 ml of tap water as a stock ingredient, and the immersion liquid was allowed to stand for 1 hour in an environment with an external temperature of 10°C without irradiating microwaves. The internal temperature of the liquid is also 10°C).

Then, one hour after the start of extraction, the soaking liquid was stirred, filtered, and then diluted eight times (soup stock) to measure the concentration of glutamic acid, which is a flavor component of kelp. Table 1 below shows the measurement results of glutamic acid concentration in Example 1 and Comparative Example 1.
As shown in Table 1, in Example 1 in which umami components were extracted by microwave irradiation, glutamic acid, which is an umami component, was 44% higher than in Comparative Example 1, in which umami components were extracted without microwave irradiation. increased (1.44 times).

In addition, the absorbance of the diluted soup stock of Example 1 and Comparative Example 1 was measured at 220 to 320 nm to create a light absorption spectrum. FIG. 3 is a graph showing light absorption spectra measured in Example 1 and Comparative Example 1. The example shown in FIG. 3 also illustrates the light absorption spectrum of a sodium glutamate aqueous solution in which only sodium glutamate is dissolved in tap water so that the concentration of sodium glutamate is 125 ppm as Reference Example 1. As shown in Figure 3, in Example 1, the absorbance in the wavelength range of 220 to 260 nm was lower than that in Comparative Example 1, and the elution of nucleic acids, amino acids, water-soluble polymers, etc. from the stock raw materials was suppressed. The results showed that As shown in Reference Example 1, glutamic acid has little light absorption in the wavelength range of 220 to 320 nm, and the amount of glutamic acid has almost no effect on the light absorption spectrum. This is thought to be due to components other than glutamic acid, including glutamic acid. Therefore, when kelp is used as a stock ingredient only and umami components are extracted by irradiating microwaves, it is possible to increase the amount of glutamic acid extracted compared to the case without irradiating microwaves, as well as to remove unpleasant tastes. It was found that the elution of components could be suppressed.

(Example 2)
In Example 2, only 4 g of irico was soaked in 400 ml of tap water as a stock raw material, and the soaking liquid was soaked in a microtube for 1 hour so that the internal temperature of the soaking liquid was 15°C and the external temperature of the soaking liquid was 5°C. In addition to irradiating waves, cooling was performed using the cooling unit 10 and the second fan 32. In addition, as Comparative Example 2, only 4 g of irico was soaked in 400 ml of tap water as a stock ingredient, and the soaking liquid was left standing for 1 hour in an environment with an external temperature of 15°C without irradiating microwaves (in this case, The internal temperature of the immersion liquid is also 15°C).

Then, one hour after the start of extraction, the soaking liquid was stirred, filtered, and then diluted 8 times (soup stock) to measure the concentration of inosinic acid, which is a flavor component of Iliko. Table 2 below shows the measurement results of inosinic acid concentration in Example 2 and Comparative Example 2.
As shown in Table 2, in Example 2 in which umami components were extracted by microwave irradiation, the umami component inosinic acid was 31% lower than in Comparative Example 2 in which umami components were extracted without microwave irradiation. % increase was found.
In addition, as a result of measuring the absorbance at 250 nm, where inosinic acid absorbs light, for the diluted soup stock of Example 2 and Comparative Example 2, the results were 0.56 for Comparative Example 2 and 0.65 for Example 2, It was confirmed that when the stock ingredient was only irico, irradiation with microwaves increased the concentration of inosinic acid.

Furthermore, the absorbance of the diluted soup stock of Example 2 and Comparative Example 2 was measured at 220 to 320 nm to create a light absorption spectrum. FIG. 4 is a graph showing light absorption spectra measured in diluted Example 2 and Comparative Example 2. In addition, the example shown in FIG. 4 also illustrates, as Reference Example 2, the light absorption spectrum of a sodium inosinate aqueous solution in which only sodium inosinate is dissolved in tap water so that the concentration of sodium inosinate is 100 ppm. . As shown in Figure 4, in Example 2, the absorbance in the wavelength range of 220 to 280 nm was higher than that in Comparative Example 2, indicating that many nucleic acids, amino acids, and water-soluble polymers were eluted from the soup stock raw material. The results were obtained. However, as shown in Reference Example 2, inosinic acid is a type of nucleic acid and has the property of absorbing light in the vicinity of 250 nm. It is thought that it appeared in the spectrum. In other words, the measurement results of the optical absorption spectrum shown in Figure 4 are correlated with the measurement results of inosinic acid concentration in Table 2 above, and in Irico, microwave irradiation has the effect of increasing the amount of inosinic acid extracted. However, the effect of suppressing the elution of components such as off-flavors could not be confirmed.

(Example 3)
In Example 3, soup stock was produced under standard extraction conditions. Specifically, 4 g of iriko and 4 g of kelp as dashi raw materials are soaked in 400 ml of tap water, and the soaking liquid is soaked with 1 ounce of water so that the internal temperature of the soaking liquid is 15°C and the external temperature of the soaking liquid is 5°C. Microwave irradiation was performed for a certain period of time, and cooling was performed using the cooling unit 10 and the second fan 32. In addition, as Comparative Example 3, 4 g of iriko and 4 g of kelp as stock ingredients were soaked in 400 ml of tap water, and the soaking liquid was allowed to stand for 1 hour in an environment with an external temperature of 15°C (in this case, the internal temperature of the soaking liquid was also 15℃).

Then, one hour after the start of extraction, the immersion liquid was stirred and filtered, and the inosinic acid concentration and glutamic acid concentration were measured for the immersion liquid (stock) diluted 9 times. Table 3 below shows the measurement results of inosinic acid concentration and glutamic acid concentration in Example 3 and Comparative Example 3.
As shown in Table 3, in Example 3 in which microwave irradiation was performed, inosinic acid, which is a flavor component abundant in iriko, increased by 19% compared to Comparative Example 3 in which microwave irradiation was not performed. , glutamic acid, which is a flavor component that is abundant in kelp, increased by 231% (3.31 times). In particular, when compared to Example 1 in which the dashi stock was prepared using only kelp, in Example 3 in which the dashi stock was prepared by combining kelp and irico, the extraction efficiency of glutamic acid was greatly improved (from 1.44 times to 3.31 times). improved).
In addition, as a result of measuring the absorbance at 250 nm, where inosinic acid absorbs light, for the diluted soup stock of Example 3 and Comparative Example 3, the results were 0.33 for Comparative Example 3 and 0.39 for Example 3. In terms of absorbance, it was confirmed that inosinic acid increases when irradiated with microwaves in the case of a soup stock made from kelp and iriko.

In addition, the absorbance of the diluted soup stock of Example 3 and Comparative Example 3 was measured at 220 to 320 nm to create a light absorption spectrum. FIG. 5 is a graph showing light absorption spectra measured in Example 3 and Comparative Example 3. As shown in Figure 5, in Example 3, even though the amount of dissolved inosinic acid is increased compared to Comparative Example 3, the absorbance in the wavelength range of 240 nm or less is lower, and the It was found that the elution of components other than umami components, such as off-flavors, was suppressed.

From these measurement results of glutamic acid concentration and optical absorption spectra, we found that when using a soup stock material made from a combination of irico and kelp, irradiation with microwaves promotes the extraction of inosinic acid and glutamic acid. It was found that while the amount of glutamic acid extracted was doubled, the elution of components including unpleasant tastes could be suppressed.

(Examples 4 to 6)
In Example 3 described above, microwave irradiation was performed so that the internal temperature of the immersion liquid was 15°C and the external temperature was 5°C. On the other hand, in Example 4, soup stock was produced under the same conditions as Example 3, except that microwave irradiation was performed so that the internal temperature of the soaking liquid was 20°C and the external temperature was 5°C. Ta. Furthermore, in Example 5, the conditions were the same as in Example 3 (the internal temperature of the immersion liquid The difference between the temperature and the external temperature was also 10°C, the same as in Example 3). Furthermore, in Example 6, the conditions were the same as in Example 3, except that microwave irradiation was performed so that the internal temperature of the immersion liquid was 5°C and the external temperature of the immersion liquid was -5°C. The soup stock was produced at the same temperature as in Example 3 (the difference between the temperature and the external temperature was 10°C). In addition, as Comparative Examples 4 and 5, the immersion liquid was left standing in an environment with an external temperature of 20°C for 1 hour without irradiating microwaves (in this case, the internal temperature of the immersion liquid was also 20°C), and the comparison example As No. 6, the immersion liquid was allowed to stand for 1 hour in an environment with an external temperature of 5° C. without irradiating microwaves (in this case, the internal temperature of the immersion liquid was also 5° C.).

The immersion liquids of Examples 4 to 6 and Comparative Examples 4 to 6 were stirred 1 hour after the start of extraction, filtered, and then diluted 9 times (stock) to determine the concentration of glutamic acid and inosinic acid. It was measured. Table 4 below shows the measurement results of the concentrations of glutamic acid and inosinic acid in Examples 4 to 6 and Comparative Examples 4 to 6. In addition, in Table 4 below, the internal temperature and external temperature of the immersion liquid at the time of extraction are also described as extraction conditions.
As shown in Table 4, in Examples 4 to 6 in which umami components were extracted by irradiating microwaves, glutamic acid was 70% lower than in Comparative Examples 4 to 6 in which umami components were extracted without irradiating microwaves. %, 285%, and 43%, and inosinic acid, which is a flavor component, also increased by 13%, 13%, and 4%, respectively.
Further, as a result of measuring the absorbance at 250 nm of the diluted broths of Example 4 and Comparative Example 4, the results were 0.32 for Comparative Example 4 and 0.37 for Example 4. Similarly, as a result of measuring the absorbance at 250 nm of the diluted broths of Example 5 and Comparative Example 5, the results were 0.33 for Comparative Example 5 and 0.39 for Example 5. Thus, in Examples 4 and 5, it was confirmed from the absorbance that the amount of inosinic acid extracted increased even when a soup stock material containing irico and kelp was used and irradiated with microwaves.

Furthermore, when comparing Example 5 and Example 6, in which the temperature difference between the external temperature and internal temperature of the immersion liquid is the same, 10°C, Example 5, in which the internal temperature of the immersion liquid is 20°C, is more The increase rate of extracted glutamic acid was increased by irradiation. From this, it was found that even if the internal temperature of the immersion liquid was raised to 20° C., the improvement in the extraction efficiency of glutamic acid by microwave irradiation was maintained. Although not shown, if the internal temperature of the immersion liquid exceeds 25°C, many unpleasant tastes will be extracted, so it is preferable that the internal temperature of the immersion liquid be 20°C or lower. Furthermore, if the internal temperature of the dipping liquid is set to below 0°C, it will take a long time to extract the flavor components, so it is preferable that the internal temperature of the dipping liquid is 0°C or higher.

Furthermore, when comparing Example 5 and Example 4 in which the internal temperature of the immersion liquid was the same at 20°C, it was found that Example 5 had a smaller temperature difference of 10°C between the internal temperature of the immersion liquid and the external temperature. The increase rate of extracted glutamic acid was increased by irradiation. From this, it was found that if the temperature difference between the internal temperature and external temperature of the immersion liquid was increased to a range exceeding 15° C., the extraction efficiency of glutamic acid by microwave irradiation would be reduced. Although not shown, it was found that the extraction efficiency of glutamic acid by microwave irradiation was also lowered when the temperature difference between the internal temperature and external temperature of the immersion liquid was less than 5°C.
In addition, in Examples 4 to 6, in which umami components were extracted by irradiating microwaves, the temperature of the surface in contact with the outside air was lower than in Comparative Examples 4 to 6, in which umami components were extracted without irradiating microwaves. Therefore, it is possible to prevent the soup stock from being spoiled by microorganisms.

In addition, the absorbance of the diluted soup stock of Examples 4 and 5 and Comparative Examples 4 and 5 was measured at 220 to 320 nm to create a light absorption spectrum. FIG. 6 is a graph showing the light absorption spectra measured in Example 4 and Comparative Example 4, and FIG. 7 is a graph showing the light absorption spectra measured in Example 5 and Comparative Example 5. As shown in Figure 6, in Example 4, the absorbance in the wavelength range of 240 to 280 nm was higher than in Comparative Example 4, indicating that more nucleic acids, amino acids, water-soluble polymers, etc. were eluted from the stock raw material. The results were obtained. Similarly, as shown in FIG. 7, in Example 5, the absorbance in the wavelength range of 240 to 280 nm was higher than in Comparative Example 5, and more nucleic acids, amino acids, water-soluble polymers, etc. were eluted from the soup stock raw material. The result was obtained.

Furthermore, compared to Example 3, in which the stock was extracted under standard extraction conditions, in Example 5, where the internal temperature was as high as 20°C, the rate of increase in glutamic acid concentration increased by 281%, which was as high as in Example 3. In Example 4, in which the temperature difference between the internal temperature and the external temperature was as large as 15°C, the rate of increase in the glutamic acid concentration was as low as 70%. It was found that the extraction of glutamic acid was further promoted by keeping the temperature below 10°C. Furthermore, compared to Example 3, in Example 5, the external temperature and internal temperature were each 5°C higher, so the extraction efficiency of glutamic acid increased, but looking at the light absorption spectrum, the absorbance at 240 nm or less also increased. It is thought that the elution of components such as off-flavors was also promoted. From these results, it was found that the standard extraction conditions of Example 3 were better able to extract flavor components without increasing the undesirable taste than the extraction conditions of Examples 4 and 5.

(Examples 7 to 9)
In Examples 7 to 9, soup stock was produced under the same extraction conditions as in Example 3, except that the extraction time was changed and microwave irradiation was performed. Specifically, in Examples 7 to 9, 4 g of iriko and 4 g of kelp as stock ingredients were soaked in 400 ml of tap water, and the internal temperature of the soaking liquid was 15°C, and the external temperature of the soaking liquid was 5°C. Microwave irradiation was performed for 30 minutes (Example 7), 2 hours (Example 8), or 4 hours (Example 9), and cooling was performed using the cooling unit 10 and the second fan 32 so that In addition, as Comparative Examples 7 to 9, 4 g of iriko and 4 g of kelp as stock ingredients were soaked in 400 ml of tap water, and the soaking liquid was not irradiated with microwaves for 30 minutes in an environment with an external temperature of 15°C (Comparative Example 7 ), 2 hours (Comparative Example 8), or 4 hours (Comparative Example 9). Further, as Reference Example 3, 4 g of iris and 4 g of kelp as stock ingredients were soaked in 400 ml of tap water, and the soaked liquid was boiled and held for 5 minutes to extract the flavor components (hereinafter also referred to as hot water extraction).

Then, 30 minutes, 2 hours, or 4 hours after the start of extraction, the immersion liquid was stirred, filtered, and then diluted 9 times (stock). The concentrations of glutamic acid and inosinic acid were measured. Table 5 below shows Example 7 and Comparative Example 7 where the extraction time was 30 minutes, Example 8 and Comparative Example 8 where the extraction time was 2 hours, Example 9 and Comparative Example 9 where the extraction time was 4 hours, The measurement results for Reference Example 3, which was extracted with hot water, are shown. In Table 5 below, extraction time is also listed as an extraction condition.
As shown in Table 5, in Example 7, in which the umami components were extracted for 30 minutes with microwave irradiation, compared to Comparative Example 7, in which the umami components were extracted for 30 minutes without microwave irradiation, the umami components were It was found that the amount of glutamic acid extracted increased by 73%. In addition, in Example 8, in which the umami flavor components were extracted for 2 hours by microwave irradiation, the extraction of glutamic acid, which is a umami flavor component, was more effective than in Comparative Example 8, in which the umami flavor components were extracted for 2 hours without microwave irradiation. It was found that the volume increased by 53%. Furthermore, in Example 9, in which umami components were extracted for 4 hours by microwave irradiation, the extraction of glutamic acid, which is an umami component, was more effective than in Comparative Example 9, in which umami components were extracted for 4 hours without microwave irradiation. It was found that the volume increased by 258%.
In addition, as a result of measuring the absorbance at 250 nm, where inosinic acid absorbs light, for the diluted soup stock of Example 7 and Comparative Example 7, the results were 0.26 for Comparative Example 7 and 0.25 for Example 7. . Similarly, as a result of measuring the absorbance at 250 nm, where inosinic acid absorbs light, for the diluted soup stock of Example 9 and Comparative Example 9, the results were 0.48 for Comparative Example 9 and 0.52 for Example 9. Ta.
From these results, it was found that in extraction of glutamic acid by microwave irradiation, improvement in extraction efficiency was observed up to at least 4 hours of extraction time. In Examples 7 to 9 and Comparative Examples 7 to 9, more inosinic acid was extracted with microwave irradiation than with no microwave irradiation, but the difference was small.

In addition, the absorbance of the diluted broths of Examples 7 and 9, Comparative Examples 7 and 9, and Reference Example 3 was measured at 220 to 320 nm to create a light absorption spectrum. Here, FIG. 8(A) shows the light absorption spectra in Example 7 and Comparative Example 7 with an extraction time of 30 minutes, and FIG. 8(B) shows the optical absorption spectra of Example 9 and Comparative Example with an extraction time of 4 hours. The light absorption spectrum in Example 9 is shown, and FIG. 8(C) shows the light absorption spectrum in Reference Example 3 extracted with hot water. As shown in FIG. 8(A), when the extraction time was set to 30 minutes, in Example 7 where microwave irradiation was performed, compared to Comparative Example 7 where microwave irradiation was not performed, the entire wavelength range from 220 to 320 nm It was found that the absorbance was low, and the elution of nucleic acids, amino acids, water-soluble polymers, etc. from the stock raw material was suppressed. On the other hand, as shown in FIG. 8(B), when the extraction time was set to 4 hours, in Example 9 in which microwave irradiation was performed, the wavelength of 220 to 260 nm was higher than in Comparative Example 9 in which microwave irradiation was not performed. The results showed that the absorbance in the entire region was high, and that more nucleic acids, amino acids, water-soluble polymers, etc. were eluted from the stock raw materials.

Furthermore, when comparing Example 7 and Example 9, in Example 9 where the extraction time was 4 hours, the absorbance was higher in the wavelength range of 220 to 280 nm compared to Example 7 where the extraction time was 30 minutes. . From these results, it was found that by lengthening the extraction time, the amount of umami components glutamic acid and inosinic acid extracted increases, while the elution of components other than umami components such as off-taste also increases. Furthermore, when comparing Example 9 and Reference Example 3, the light absorption spectra of Example 9, in which microwave irradiation was performed for 4 hours, and Reference Example 3, in which hot water extraction was performed, were similar; It is thought that the extraction of flavor components from the stock ingredients is almost completed by performing irradiation for 4 hours.

(Example 10)
In Example 10, soup stock was produced under the same extraction conditions as in Example 3, except that sodium inosinate, which is an umami seasoning, was added instead of irico and microwave irradiation was performed. Specifically, in Example 10, 4 g of kelp was immersed in 400 ml of an aqueous solution in which 100 ppm of sodium inosinate was added to tap water. Microwave irradiation was performed for 1 hour, and cooling was performed using the cooling unit 10 and the second fan 32 so that the external temperature was 5°C. Further, as Comparative Example 10, an immersion solution in which 4 g of kelp was immersed in 400 ml of an aqueous solution in which sodium inosinate was added to tap water at 100 ppm was left standing at an external temperature of 15° C. for 1 hour.

Then, one hour after the start of extraction, the immersion liquid was stirred, filtered, and the concentration of glutamic acid in the 9-fold diluted immersion liquid (stock) was measured. Table 6 below shows the measurement results of glutamic acid concentration in Example 10 and Comparative Example 10.
As shown in Table 6 above, in Example 10, in which umami components were extracted by microwave irradiation, glutamic acid, which is an umami component, was extracted, compared to Comparative Example 10, in which umami components were extracted without microwave irradiation. Volume increased by 28%. Thus, it was found that the amount of glutamic acid extracted can also be increased when sodium inosinate is added instead of irico.
In addition, as a result of measuring the absorbance at 250 nm of the diluted soup stock of Example 10 and Comparative Example 10, it was found to be 0.33 in both Example 10 and Comparative Example 10, indicating that the concentration of inosinic acid was almost the same.

Furthermore, the absorbance of the diluted soup stock of Example 10 and Comparative Example 10 was measured at 220 to 320 nm to create a light absorption spectrum. FIG. 9 is a graph showing light absorption spectra measured in Example 10 and Comparative Example 10. As shown in FIG. 9, in Example 10, in which the umami components were extracted by microwave irradiation, compared to Comparative Example 10, in which the umami components were extracted without microwave irradiation, the Absorbance has decreased. Considering that the dissolved amount of inosinic acid remained almost unchanged, it can be seen that in Example 10, compared to Comparative Example 10, the elution of components other than umami components such as miscellaneous flavors from the stock raw materials was suppressed. Understood.

In this way, from the measurement results of glutamic acid concentration and the results of the optical absorption spectrum, even when inosinic acid is added instead of irico, glutamic acid can be reduced by microwave irradiation in the same way as in Example 3 in which irico was added. It is thought that this has the effect of not only promoting extraction but also suppressing the elution of components such as off-flavors.

(Examples 11 to 13)
In Examples 11 to 13, soup stock was produced under the same extraction conditions as in Example 3, except that the amount of stock raw materials used was changed. Specifically, in the above-mentioned Example 3, 4 g of Iriko and 4 g of kelp were soaked in 400 ml of tap water to produce the soup stock. On the other hand, in Example 11, 5 g of iriko and 3 g of kelp as stock ingredients were soaked in 400 ml of tap water, and the internal temperature of the soaking liquid was 15°C, and the external temperature of the soaking liquid was 5°C. Microwave irradiation was performed for 1 hour, and cooling was performed using the cooling unit 10 and the second fan 32. In addition, in Example 12, 3 g of iriko and 5 g of kelp as stock ingredients were immersed in 400 ml of tap water, and 1 hour was added so that the internal temperature of the immersion liquid was 15°C and the external temperature of the immersion liquid was 5°C. Microwave irradiation was performed for a certain period of time, and cooling was performed using the cooling unit 10 and the second fan 32. Furthermore, in Example 13, 2 g of iriko and 6 g of kelp as stock ingredients were immersed in 400 ml of tap water. Microwave irradiation was performed for a certain period of time, and cooling was performed using the cooling unit 10 and the second fan 32. In addition, Comparative Example 11 is an immersion liquid in which 5 g of iris and 3 g of kelp are immersed in 400 ml of tap water, Comparative Example 12 is an immersion liquid in which 3 g of iris and 5 g of kelp are immersed in 400 ml of tap water, and Comparative Example 13 is a dipping liquid in which 3 g of iris and 5 g of kelp are immersed in 400 ml of tap water. An immersion solution in which 2 g of Iriko and 6 g of kelp were immersed in 400 ml of tap water was left standing for 1 hour in an environment with an external temperature of 15°C (in this case, the internal temperature of the immersion solution was also 15°C).

Then, one hour after the start of extraction, the immersion liquid was stirred, filtered, and then the concentrations of glutamic acid and inosinic acid diluted nine times were measured. Table 7 below shows the measurement results of the concentrations of glutamic acid and inosinic acid in Examples 11 to 13 and Comparative Examples 11 to 13.
As shown in Table 7 above, in Examples 11 to 13 in which umami components were extracted by microwave irradiation, compared to Comparative Examples 11 to 13 in which umami components were extracted without microwave irradiation, the umami components were The amount of glutamic acid extracted increased by 20%, 16%, and 41%, respectively. Furthermore, the amount of inosinic acid extracted was 8% in Examples 11 to 13, in which umami components were extracted by microwave irradiation, compared to Comparative Examples 11 to 13, in which umami components were extracted without microwave irradiation. %, 0%, 18% increase. In this way, it was found that when the ratio of irico to kelp is less than 2 (weight of irico/weight of kelp), the amount of glutamic acid and inosinic acid extracted can be increased by performing microwave irradiation. Ta.

As described above, in the method for producing dashi according to the present embodiment, when extracting flavor components by immersing the dashi raw material in a liquid, the immersion liquid in which the dashi raw material is immersed is irradiated with microwaves. Even at extremely low temperatures, it is possible to extract umami components with higher extraction efficiency in a short time of 30 minutes to 4 hours. More preferably, the internal temperature of the immersion liquid is higher than 0°C and lower than 25°C, so that the external temperature of the immersion liquid is lower than the internal temperature of the immersion liquid. The temperature is set within a range of -5°C or higher and lower than 20°C, and the difference between the internal temperature and external temperature of the immersion liquid is set within a range of higher than 5°C and lower than 20°C. By cooling the soaking liquid at the same time as the wave irradiation, it becomes possible to extract the flavor components more efficiently. Further, as in Examples 1 and 3 described above, in the method for producing dashi according to the present embodiment, when kelp is used as a stock raw material, the extraction efficiency of glutamic acid, which is a flavor component, can be increased, and the kelp It was possible to suppress the elution of components such as off-flavors contained in the products. This is because among the components contained in kelp, glutamic acid has a relatively high microwave absorption efficiency, while components such as off-flavors (such as polysaccharides) have a relatively low microwave absorption efficiency. This is thought to be because the elution of glutamic acid is promoted even at lower temperatures, while the elution of components other than umami components such as miscellaneous tastes is suppressed due to the low temperature. Furthermore, in the present embodiment, when the joints or dried sardines were irradiated with microwaves, it was also confirmed that the extraction efficiency of inosinic acid was improved, although it was less than that of glutamic acid.

In addition, in this embodiment, by making dashi by combining kelp and knotweed or dried sardines as the dashi raw materials, the extraction efficiency of glutamic acid can be made higher than when making dashi from kelp alone. was completed. In particular, by setting the ratio of knots or dried sardines to kelp (weight of knots or dried sardines/weight of kelp) to be less than 2, the umami components could be extracted more efficiently. These results suggest that inosinic acid has the effect of increasing the extraction of glutamic acid by microwave irradiation or suppressing the elution of components other than glutamic acid from kelp. It is thought that by combining dashi stock with acid-rich stock ingredients, it is possible to synergistically increase the extraction efficiency of glutamic acid and the suppressing effect on off-flavors. In addition, in the above-mentioned examples, kelp and dried dried sardines or dried sardines were used as dashi raw materials, but guanylic acid, which is the umami component mainly contained in shiitake mushrooms, is derived from inosine, which is abundantly contained in dried sardines or dried sardines. Since it is the same nucleic acid as acid and has the same microwave absorption efficiency, it is thought that the extraction efficiency of guanylic acid can also be improved when irradiated with microwaves, similar to inosinic acid.

Although preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the description of the above embodiments. Various changes and improvements can be made to the embodiments described above, and forms with such changes and improvements are also included within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Microwave aging device 10... Cooling part 11... Cooler 12... First fan 13... Cooling chamber 20... Microwave oscillation part 21... Cable 30... Microwave aging part 31... Irradiation port 32... Second fan 33... Ripening Chamber 34... Aging chamber door 35... First minute opening 36... Second minute opening 37... Net plate 38... Chalk structure 39... Lighting section 40... Operation section 50... Control section 60... UV lamp

Claims (9)

In a method for producing soup stock in which the soup stock raw material is immersed in a liquid at 40°C or lower to extract flavor components, the microwave is irradiated by irradiating the dipping liquid in which the soup stock raw material is immersed in the liquid for a certain period of time. A method for producing dashi stock, which is characterized by extracting flavor components in a shorter time and with higher efficiency than when not using it. The method for producing soup stock according to claim 1, wherein the immersion liquid is cooled at the same time as the microwave irradiation so that the external temperature of the immersion liquid is lower than the internal temperature of the immersion liquid. The method for producing soup stock according to claim 1 or 2, wherein the microwave irradiation is performed so that the internal temperature of the immersion liquid is higher than 0°C and lower than 25°C. The method for producing soup stock according to claim 1 or 2, wherein the microwave irradiation is performed so that the external temperature of the immersion liquid is in a range of -5°C or higher and lower than 20°C. 2. The immersion liquid is cooled at the same time as the microwave irradiation so that the difference between the internal temperature and the external temperature of the immersion liquid is higher than 5°C and lower than 20°C. The method for producing soup stock described in . The method for producing soup stock according to claim 1 or 2, wherein the microwave irradiation is performed for 30 minutes or more and 4 hours or less. The method for producing dashi according to claim 1 or 2, wherein the dashi stock raw material is a dashi stock raw material that is a combination of kelp, knotweed, or dried sardines. The method for producing soup stock according to claim 7, wherein the ratio of the knots or dried sardines to kelp (weight of the knots or dried sardines/weight of kelp) in the stock raw material is less than 2. The method for producing dashi soup according to claim 1 or 2, wherein a dipping liquid in which the dashi raw material prepared by adding a flavor seasoning to kelp is immersed in the liquid is irradiated with microwaves for a certain period of time.