Method for producing koji mold tissue

Abstract

To provide a method for producing a koji mold tissue product more suitable for food.SOLUTION: A method for producing a koji mold tissue product, comprising allowing a mycelium of a koji mold to stand in an environment of 0 °C to 60 °C under conditions where the koji mold does not proliferate, wherein the production method preferably comprises culturing the koji mold to obtain the mycelium, and after recovering the cultured mycelium, allowing the recovered mycelium to stand.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a koji mold tissue product. [Background technology]

[0002] Research into alternative protein sources is progressing to solve food shortages caused by a growing global population and the environmental impact of livestock production. Alternative protein sources include plant-based meat made from soybeans and peas, cultured meat produced artificially through cell culture, edible insects such as crickets, and fermentation-derived proteins.

[0003] Fungi used as a source of fermentation-derived protein have the advantages of being fast growing and capable of multiplying in a short period of time, requiring few resources (water and land) and therefore having a low environmental impact, and their mycelium has a fibrous structure that makes it easy to create a fibrous texture, and being rich in nutrients. Technologies using koji mold as a fungus have also been developed. Koji mold has been used for many years for various purposes in traditional Japanese cuisine, and is a realistic alternative protein source from the standpoints of safety and consumer sentiment. Patent Document 1 discloses a method for producing koji mold cells for use as a meat substitute, which includes the steps of initiating cultivation of koji mold in a liquid medium, and then recovering and washing the grown cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-023172 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a method for producing a koji mold tissue product that has good taste and texture. [Means for solving the problem]

[0006] Representative aspects of the present invention include the following.

[0007] <1> A method for producing a koji mold tissue product, comprising allowing mycelium of koji mold to stand in an environment of 0°C to 60°C under conditions that do not allow the koji mold to grow. <2> The standing is carried out under conditions that satisfy at least one of the following (a) and (b): <1> The manufacturing method according to (a) anaerobic conditions, (b) Temperature conditions below 20°C or above 40°C. <3> The standing is carried out for 1 to 20 days. <1> or <2> The manufacturing method described in <4> Satisfy any of the following conditions (a-1), (b-1), and (b-2): <1> ~ <3> The manufacturing method according to any one of the above. (a-1) The mycelium is vacuum-packed, and the standing is carried out at room temperature. (b-1) The standing is carried out at 2 to 18°C. (b-2) The standing is carried out at 42 to 50°C. <5> Satisfy (a-1) <4> The manufacturing method described in

[0008] <6> obtaining the mycelium by culturing; <1> ~ <5> 1. The manufacturing method according to any one of the preceding claims. <7> The cultured mycelium is recovered and then allowed to stand. <6> The manufacturing method described in <8> After 1 to 20 days from the time of collection, the mycelium is frozen, dried, freeze-dried, or sterilized at high temperature. <7> The manufacturing method described in <9> The culture is a culture in a liquid medium. <6> ~ <8> 1. The manufacturing method according to any one of the preceding claims. <10> The method includes obtaining the mycelium by culturing the following (1) to (3) in this order: <6> ~ <9> a manufacturing method according to any one of the methods; (1) Initiating the cultivation of a starter koji mold in a liquid medium containing at least a carbon source; (2) adding a first nitrogen source to the liquid medium after the koji mold starts to grow in the liquid medium; and (3) After the addition of the first nitrogen source, the culture is continued for the time required for the production of a protein using the first nitrogen source as a raw material.

[0009] <11> A koji mold tissue product containing koji mold mycelium, the koji mold tissue product contains at least three amino acids selected from the group consisting of aspartic acid, threonine, serine, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine, each of which is contained in an amount of 10 mg / g or more relative to the total dry mass of the koji mold tissue product; A koji mold tissue in which all three of the above amino acids are found inside the mycelium. <12> It is edible, <11> The koji mold tissue product according to claim 1. [Effects of the Invention]

[0010] According to the method for producing a koji mold tissue product of the present invention, a koji mold tissue product having good taste and texture can be produced in a simple procedure. [Brief explanation of the drawings]

[0011] [Figure 1] The glutamic acid content of the koji mold tissue obtained by leaving the mycelium at rest at 4°C for 1, 3, 5, 7, and 9 days is shown. [Figure 2] The glutamic acid content of koji mold tissue obtained by leaving mycelium at rest for 1, 2, and 3 days at 4°C, 10°C, and 45°C, respectively, is shown. [Figure 3] The free amino acid content of the koji mold tissue obtained by leaving the mycelium at rest at 4°C for 7 days is shown. [Figure 4] The free amino acid content of koji mold tissue obtained by leaving mycelium in a vacuum pack at 4°C or 20°C for 7 days is shown. [Figure 5] The hardness of the koji mold tissue obtained by leaving the mycelium in a vacuum pack in an incubator at 4°C and 20°C for 1 day, 3 days, and 5 days, respectively, is shown. [Figure 6] The effect of the number of days of culture on enzyme activity is shown. [Figure 7]The protein content of mycelia obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar or in a liquid medium containing 2% brown rice flour with yeast extract added is shown. [Figure 8] The protein content of mycelia obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar with different amounts of yeast extract added is shown. [Figure 9] The protein content of mycelia obtained by culturing in liquid medium containing 2% or 4% raw sugar with different amounts of yeast extract added is shown. [Figure 10] The protein content of mycelia obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar, to which casamino acids or peptone were added, is shown. [Figure 11] The wet weight and protein content of the mycelium obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar to which yeast extract or casamino acids were added 24 hours or 4 hours before harvesting the koji mold tissue are shown. [Figure 12] The wet weight and protein content of mycelia obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar with the addition of yeast extract are shown. [Figure 13] The wet weight and protein content of mycelia obtained by culturing in a liquid medium containing 2% sake lees and 2% raw sugar with yeast extract added at different times are shown. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. Hereinafter, when "%" is used to describe a component in a liquid medium, it means a mass volume percent concentration relative to the volume of the liquid medium (w / v % concentration) unless otherwise specified.

[0013] <Method of manufacturing koji mold tissue product> The present invention relates to a method for producing a koji mold tissue product. As used herein, koji mold tissue refers to a substance that contains or consists of mycelium. When koji mold is cultured in a liquid medium, for example, the koji mold aggregates and may take the form of pellets, which are spherical, roughly spherical, or tablet-like, or may take the form of fibers (filaments) such as lines or fibers. The form of the mycelium is not particularly limited, and may be pellet-like, fibrous, or non-aggregated. It may also be a mixture of two or more of these forms. Note that a fibrous form refers to mycelium that has been dehydrated using a Nutsche or similar device and has become completely sheet-like. A pellet-like form refers to a form in which the mycelium remains partially or completely intact even after dehydration using a Nutsche or similar device. In this specification, the term "Koji mold tissue product" particularly refers to a product obtained by allowing the mycelium obtained by culture to stand under the conditions described below.

[0014] <Stand still> The method for producing a koji mold tissue product of the present invention comprises allowing the mycelium obtained by culture to stand in an environment of 0°C to 60°C under conditions that do not allow the koji mold to grow. For example, it is known that meat or fish meat undergoes a process of standing at low temperatures to relieve rigor mortis, change its texture and taste, and improve its eating quality; this process is called aging. Aging primarily utilizes the mechanism by which proteases (protein-degrading enzymes) and the like break down proteins, thereby increasing peptides and free amino acids that are the source of umami and flavor, and softening muscle tissue. The present invention was the first to discover that koji mold tissue products, including mycelium obtained by culturing koji mold, can also increase free amino acids and change texture by standing under specified conditions, resulting in effects similar to those of meat or fish meat aging.

[0015] By leaving the mycelium obtained by culturing under the above conditions, the proteins are decomposed by proteases to produce free amino acids. As a result, it is thought that the umami and flavor of the koji mold tissue product obtained increases. Furthermore, if fibrous proteins are present in the mycelium, they are decomposed by proteases, which is thought to soften the koji mold tissue product.

[0016] Proteases are thought to be active during the cultivation of koji mold and to break down proteins within the mycelium, but when the koji mold is separated (recovered) from the culture medium under conditions in which it does not grow, proteases act within the mycelium, where no new proteins are produced. This increases the amount of protein broken down relative to the total protein content in the koji mold tissue, and also increases the amount of free amino acids.

[0017] The free amino acids that increase after standing in the koji mold tissue product of the present invention are derived from proteins in the koji mold mycelium and are produced by the action of proteases within the mycelium. Therefore, unlike amino acids that are added to the mycelium later or amino acids that are produced by the action of proteases on proteins outside the mycelium, they are not damaged by washing or the like.

[0018] The standing is carried out in an environment of 0°C to 60°C under conditions that do not allow the growth of koji mold. The conditions that do not allow the growth of koji mold may be conditions under which mycelial growth cannot be confirmed visually or under a microscope, even after standing for, for example, one day or more. These conditions may be conditions under which koji mold can survive or not. However, these conditions must be conditions under which proteases in the koji mold mycelium are active. These conditions must be conditions under which at least some of the proteases present in the mycelium and involved in the degradation of proteins in the mycelium are active. The present inventors confirmed an increase in free amino acids in the mycelium at temperatures of 0°C to 60°C, which is thought to be due to protease activity. It is preferable that the temperature be in the range of 0°C to 60°C, and that the conditions are such that the koji mold does not grow, and at the same time, microbial contamination can be suppressed.

[0019] Specifically, the above conditions include satisfying at least one of the following conditions (a) and (b): (a) anaerobic conditions, (b) Temperature conditions below 20°C or above 40°C.

[0020] (anaerobic conditions) Anaerobic conditions refer to conditions in which the oxygen concentration is so low that koji mold cannot grow, such as an oxygen concentration of 1% or less. The method for placing mycelia under anaerobic conditions is not particularly limited, but examples include storing mycelia separated from the culture medium and with a certain amount of moisture and other substances removed, particularly recovered mycelia, in an airtight container or bag, storing them in an airtight container or bag with an oxygen absorber, or placing mycelia under a nitrogen or carbon dioxide atmosphere. Even if the oxygen concentration exceeds 1% at the start of storage, anaerobic conditions can be achieved by the koji mold consuming the remaining oxygen in the airtight container or bag. Furthermore, since mycelia can be prepared in a shape that allows the surface to easily adhere to plastic wrap, wrapping them in food wrap film can also consume oxygen within the wrap film, creating anaerobic conditions. While the wrap film is not particularly limited, wrap film with a high gas barrier property is preferred, and for example, polyvinylidene chloride film is preferably used. Preferably, anaerobic conditions are achieved by vacuum-packing the mycelium.

[0021] The incubation under anaerobic conditions is carried out in an environment of 0° C. to 60° C., preferably 2° C. to 50° C., more preferably 10° C. to 45° C., and even more preferably 15° C. to 40° C. Under anaerobic conditions, the incubation can be carried out at room temperature (20° C. to 30° C.).

[0022] (Temperature conditions below 20°C or above 40°C) The standing can also be carried out at a temperature below 20°C or above 40°C. Under these conditions, the growth of koji mold can be suppressed without anaerobic conditions. More specifically, the standing can be carried out at a temperature between 0°C and below 20°C or above 40°C and below 60°C, and is preferably carried out at a temperature between 2°C and below 18°C ​​or above 42°C and below 50°C. Anaerobic conditions may also be used in addition to temperature conditions below 20°C or above 40°C.

[0023] (Standing time) The time for standing can be determined appropriately depending on other conditions such as temperature and whether or not anaerobic conditions are used, and is usually 12 hours or more. For example, it can be left for 1 day or more, 2 days or more, or 3 days or more. It can also be left for 20 days or less, 15 days or less, or 10 days or less. The time can be any combination of the above lower and upper limits. The standing is carried out after culturing the koji mold. When the mycelium is recovered after the culture, the standing may be carried out immediately after the mycelium is recovered, or after the mycelium is left at room temperature for less than one day, preferably 3 to 12 hours, after the mycelium is recovered, or after the mycelium is frozen and stored (for example, for one day to one year) after the mycelium is recovered.

[0024] After the completion of the standing, drying treatment such as freeze-drying and sterilization treatment can be carried out. Examples of sterilization treatment include high heat treatment and UV irradiation.

[0025] Examples of standing conditions include, but are not limited to, the following: -Incubate at 0-15°C for 3-10 days. -Incubate at 42-50℃ for 12 hours to 7 days. · Vacuum pack the mycelium and leave it at room temperature for 3 to 10 days. The mycelium is vacuum packed and incubated at 0-20°C for 7-20 days. The mycelium is vacuum packed and incubated at 30-50°C for 12 hours to 7 days.

[0026] <Koji mold> As for koji mold, any koji mold that has traditionally been used in the production of sake, miso, soy sauce, mirin, shochu, etc. can be used. Specifically, strains such as Aspergillus oryzae, Aspergillus sojae, Aspergillus awamori, Aspergillus kawachii, Aspergillus glaucus, Aspergillus tamari, Aspergillus luchuensis, and Aspergillus niger can be used. Aspergillus oryzae, Aspergillus sojae, Aspergillus kawachii, and Aspergillus leuconoensis are preferred, with Aspergillus oryzae being more preferred, as they are safe microorganisms that have been used in the Japanese industrial sector for brewing soy sauce, miso, and other products. Commercially available koji molds can be used for cultivation, and can be purchased, for example, from the Biotechnology Center of the National Institute of Technology and Evaluation.

[0027] <Cultivation: Aspergillus oryzae> The production method of the present invention may include a step of culturing koji mold to obtain mycelia. By adjusting the culture conditions, mycelia with a higher protein content can be obtained. The koji mold used as a culture starter may be a mycelium tissue obtained by liquid culture of koji mold, or a collection of spores on which koji mold grows by solid culture, or koji obtained by growing and propagating koji mold on grains such as rice, beans, or wheat, or a processed product thereof. The koji mold used as a starter is preferably one that contains at least spores that are normally used as "seed koji."

[0028] In the culture, for example, commercially available koji mold cultured by a fungal culture method known to those skilled in the art can be used as a starter. To produce koji mold in a large-capacity culture tank, mycelium is formed in a small culture tank and then subcultured in stages. Culture to obtain a starter can be carried out, for example, on a plate medium for fungal culture (such as PDA agar medium) under heating. For example, the culture temperature is 20 to 40°C, and the culture time is approximately 24 to 192 hours. The koji mold after culture or the spores obtained after culture can be used as a starter. When using spores, they can be used as a suspension at a desired concentration. For example, the spores can be used as a suspension in sterilized water containing a surfactant such as Tween 20 or Tween 80.

[0029] The number of spores can be measured by dropping the spore suspension onto a hemocytometer (such as a Thoma counting chamber) and counting them under a microscope using standard methods. Alternatively, an automatic particle counting device used for the same purpose may be used.

[0030] In the culture, the starter koji mold can be added to the liquid medium to start the culture. When spores are used, the amount of koji mold added to the liquid medium at the start of the culture is, for example, 10 3 pieces / ml~10 10 / ml, preferably 10 4 pieces / ml~10 7 / ml, more preferably 10 4 pieces / ml~10 6 It is sufficient if it is 1 / ml.

[0031] <Culture: Medium> The culture is preferably carried out in a liquid medium. The liquid medium is not particularly limited as long as it contains components that serve as carbon and nitrogen sources necessary for culturing the koji mold. Examples of carbon sources include sugars such as glucose, maltose, sucrose, lactose, starch, and blackstrap molasses. Unrefined raw sugar is particularly preferred as a sugar. Carbon sources may also be sources other than sugars, and may also contain proteins, vitamins, and the like. For example, fermentation residues such as sake lees, soy sauce lees, beer lees, and shochu lees, as well as rice bran, wheat bran, and residues of other grain (rice, barley, beans, etc.) powders or paste-processed grains, can also be used. These are grain derivatives with relatively limited uses, and are preferred from the perspective of effective resource utilization. Of these, fermentation residues or raw sugars can be preferably added to the liquid medium. Fermentation residues and raw sugars may be added alone, or two or more of them may be added. When two or more of them are used, for example, sake lees and raw sugars are preferred.

[0032] Examples of nitrogen sources that can be used include amino acids, peptides, inorganic nitrogen compounds (e.g., ammonia, ammonium sulfate, ammonium chloride, etc.), and mixtures thereof. It is preferable to use a component containing amino acids or low-molecular-weight peptides as the nitrogen source, and particularly preferred is an amino acid-containing component containing a high concentration of amino acids or low-molecular-weight peptides. Examples of amino acid-containing components include yeast extract, malt extract, barley fermentation extract, meat extract, casamino acids, and peptone. Protein-containing fermentation residues, such as those listed in the previous section, can also be used as nitrogen sources. Preferred nitrogen sources include yeast extract, malt extract, barley fermentation extract, fermentation residue, or a mixture of two or more of these, with yeast extract being more preferred. Extracts are extracted components; for example, yeast extract is an extracted component of the chemical or physical hydrolysis of yeast cells. Casamino acids are casein acid hydrolysates, and peptones are enzymatic casein hydrolysates, enzymatic soy protein hydrolysates, etc. According to the document (Basic Bioengineering Course, Bio Trivia "Do You Know the Ingredients of Culture Media?", 2011, No. 4, p. 195), yeast extract and meat extract contain 68% and 80% peptides and amino acids, respectively, while the peptones Bacto Tryptone (derived from milk casein), Bacto peptone (derived from meat), and Bacto Soytone contain approximately 81%, 97%, and 59% peptides and amino acids, respectively.

[0033] In the production of koji mold mycelium using sake lees or brown rice flour as ingredients in a liquid medium, the protein content of the resulting mycelium can be increased by adding about 1% of yeast extract, casamino acids, peptone, or a mixture of two or more of these to the liquid medium, thereby achieving a protein content of, for example, more than 40% by mass. Because ingredients such as yeast extract, which contain high concentrations of amino acids and low-molecular-weight peptides, are expensive, obtaining koji mold tissue products with a high protein content in a medium containing these ingredients at 1.5% or less makes it possible to produce high-protein products at low cost.

[0034] In liquid media, medium components such as grain derivatives and fermentation residues may be present in water as solids without being completely dissolved. After mixing the medium components in water, it is preferable to sterilize the mixture in an autoclave or the like before use as a liquid medium.

[0035] If necessary, inorganic salts may be added to the liquid medium, such as phosphate salts, magnesium salts, iron salts, sodium salts, potassium salts, calcium salts, zinc salts, copper salts, manganese salts, and cobalt salts.

[0036] The liquid medium may be PDB (Potato Detoxulose Broth), which is used for culturing various microorganisms. Alternatively, the liquid medium or medium components may be solutions, suspensions (such as broth), residues, or solids containing carbon and nitrogen sources generated during food production, or nutritional components derived from non-standard agricultural products.

[0037] <Culture: Post addition> By adding the first nitrogen source to the liquid medium after the starter koji mold has begun to grow following the initiation of culture, the protein content in the resulting mycelium (koji mold tissue) can be increased. In this specification, the addition of a nitrogen source after the initiation of culture as described above is sometimes referred to as "late addition," and the point in time at which it is added is sometimes referred to as "time of late addition."

[0038] As used herein, the term "first nitrogen source" refers to the component in a liquid medium that has the highest nitrogen content. The first nitrogen source may consist of one component or two or more components. For example, the term "first nitrogen source" does not refer to a carbon source or other components that contain trace amounts of nitrogen. The "first nitrogen source" is preferably one of the preferred examples of the "nitrogen source," and particularly preferably yeast extract, casamino acids, peptone, or a mixture of two or more of these.

[0039] When the first nitrogen source is added later, the protein content of the resulting mycelium can be higher than when the entire amount is included in the liquid medium at the start of cultivation. Without being bound by any theory, this is thought to be because, as the mycelium grows during cultivation, the protein amount also increases. As the mycelium mass increases, the accumulated protein is consumed by the koji mold. However, later addition of the first nitrogen source efficiently maintains the accumulated protein. This is presumably because the first nitrogen source, which is primarily used as a raw material for protein production, is efficiently consumed by adding it after the koji mold has reached a state in the liquid medium where it can produce protein. Therefore, the amount of the first nitrogen source added to the liquid medium at the start and the amount of the first nitrogen source added later can be adjusted appropriately depending on the type of first nitrogen source and the culture conditions. Based on the above-presumed principle, the amount of the first nitrogen source added later is preferably more than 50% by mass of the total amount of the first nitrogen source added to the liquid medium, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. From the viewpoint of simplifying the procedure, it is preferable that the first nitrogen source is not added to the liquid medium at the start of culture, but is added only at a later time after the start of culture.

[0040] Whether the time has passed since the starter koji mold began to grow can be confirmed, for example, by visually observing the amount of bacterial mass in the liquid medium, measuring the pH of the liquid medium, or measuring the dissolved oxygen concentration in the liquid medium. For example, post-addition can be performed after an increase in the amount of bacterial mass, a decrease in the pH of the liquid medium, or a decrease in the dissolved oxygen concentration in the medium is confirmed. In particular, post-addition is preferably performed after sufficient growth of koji mold in the liquid medium, for example, when the increase in the amount of bacterial mass, the decrease in the pH of the liquid medium, or the decrease in the dissolved oxygen concentration in the medium have almost ceased. Under the conditions described herein, at least a portion of koji mold is considered to have begun to grow at least 8 hours after the start of culture. However, from the perspective of performing post-addition after sufficient growth of koji mold, post-addition is usually performed 18 hours or later after the start of culture, more preferably 24 hours or later, and even more preferably 36 hours or later. The start of culture typically refers to the time when the starter koji mold is added to the liquid medium.

[0041] The later addition is carried out at a point by the end of the culture when there is sufficient time to produce protein using the later-added first nitrogen source as a raw material. In particular, it is preferable that the later addition be carried out at a point when there is sufficient time to digest most of the later-added first nitrogen source. Based on the experience of the present inventors, taking into account the time it takes for a decrease in the amount of protein, which is thought to be due to decomposition within the koji mold cells, to begin, the later addition is preferably carried out at least 4 hours, more preferably 8 hours, and even more preferably 16 hours before the end of the culture.

[0042] The later addition may be carried out once or twice or more times, as long as it is within a suitable time for the later addition (for example, at least 18 hours after the start of culture and at least 4 hours before the end of culture). It is preferable to add the component multiple times sequentially in accordance with the consumption rate of the component in the liquid medium, or it is also preferable to add it once in consideration of the labor involved in the operation. It may also be added in multiple divided portions within a short period of time.

[0043] The post-addition of the first nitrogen source is preferably carried out so that the first nitrogen source is present at a concentration of 0.1 to 2%, more preferably 0.25 to 1%, relative to the volume of the liquid medium. The first nitrogen source may be added as a solution or suspension in an appropriate solvent such as sterile water, or as a sterilized, dried powder. As shown in the examples (Example R5 and Figure 11), post-addition allows the production of mycelia with a protein content of over 40% by mass, even when the amino acid-containing component in the liquid medium is only 0.25 to 0.5%.

[0044] <Cultivation: temperature conditions, procedures, etc.> The culture temperature is not particularly limited as long as it is within a temperature range in which koji mold can grow, and can be appropriately selected depending on the purpose, but is preferably 20°C to 40°C, more preferably 25°C to 37°C, and even more preferably 28°C to 32°C. By setting the culture temperature to 20°C or higher, it is possible to promote the growth of koji mold and the production of proteins. Furthermore, by setting the temperature to 40°C or lower, it is possible to prevent the koji mold from becoming unable to grow.

[0045] The culture is not particularly limited as long as it is carried out at a pH that is optimal for the growth of koji mold or allows cultivation. The pH may vary during the culture process. It may also vary depending on components added later. Unless specifically controlled, the pH of the liquid medium gradually decreases from the start to the end of the culture, but the pH is preferably about 3 to 8, and more preferably about 4 to 7, throughout the culture period.

[0046] Cultivation can be carried out by a general aerobic culture method. From the viewpoint of supplying the oxygen necessary for growth, for example, shaking culture or stirring culture using a jar fermenter can be used. Furthermore, gas supply to the culture vessel may be performed in addition to shaking and stirring. A method of achieving oxygen supply by gas supply only without shaking or stirring can also be used. In this case, gas supply may be performed so that the dissolved oxygen concentration is, for example, 1.0 ppm to 8.0 ppm.

[0047] The cultivation of koji mold may be a batch cultivation in which the cultivation is started with an initially prepared liquid medium and terminated upon recovery of the resulting cultured mycelium, or a continuous cultivation in which new liquid medium is added as the cultured mycelium is recovered and the cultivation is continued continuously. When post-addition is performed at each cultivation period, continuous cultivation may be performed by repeating the addition of new liquid medium and koji mold, cultivation, post-addition, continuation of cultivation, and recovery of cultured mycelium in this order.

[0048] The culture time is not particularly limited and can be selected appropriately depending on the purpose. For example, the culture time can be adjusted depending on the amount of koji mold at the start of culture. In the case of batch culture, in order to generally recover the cultured mycelium before the nutrients in the medium are depleted, 38 to 240 hours is preferred, 42 to 120 hours is more preferred, and 48 to 100 hours is particularly preferred. Protein can be produced by culture for 38 hours or more, and in consideration of production efficiency, it is preferable that the culture time not exceed 240 hours. In the case of continuous culture, the culture period used in batch culture can be repeated and continued, and it is also possible to repeat and continue a culture period of 12 to 38 hours (for example, 24 hours).

[0049] <Mycelium collection> The mycelia obtained by culturing may be left to stand as is after culturing, or may be recovered and then left to stand. In the step of leaving to stand, it is preferable that the mycelia are separated from the medium so as not to allow the koji mold to grow and to allow proteases in the mycelia to produce free amino acids. In other words, it is preferable that the mycelia are left to stand after being recovered.

[0050] The method for recovering mycelia is not particularly limited as long as it is a known separation method. For example, centrifugation, filtration separation, compression separation, etc. can be used as appropriate. The recovery is preferably carried out in an environment free from contamination by microorganisms other than koji mold. Examples of recovery in an environment free from contamination by microorganisms include recovery in a clean bench, recovery using a sterilized device, and recovery in a sterilized space in a clean room. Upon recovery, the mycelia are separated from the medium and a certain amount of moisture and the like have been removed. The mycelia to be left to stand may be washed with purified water or the like after recovery, or may be suspended in water or an aqueous solution containing other components. When producing a koji mold tissue product in which components contained in the liquid medium are attached separately from and not contaminated by components in the mycelium, the mycelium may be washed with purified water or the like after collection.

[0051] <Properties and uses of koji mold tissue products> The koji mold tissue product contains more free amino acids than the koji mold tissue product produced by a production method that does not include a standing step.

[0052] The free amino acid content can be measured after drying (e.g., freeze-drying) the koji mold tissue product. Since free amino acids are contained in the mycelium, the koji mold tissue product is subjected to a disruption treatment or the like so that the components in the mycelium can be measured. Measurement can be performed using any amino acid analysis method known or known to those skilled in the art. In the koji mold tissue product obtained by the production method of the present invention, for example, the free glutamic acid content is preferably 10 mg / g or more, more preferably 15 mg / g or more, even more preferably 20 mg / g or more, and particularly preferably 25 mg / g or more, based on the total dry mass. There is no upper limit, and a high value can be obtained depending on the protein content in the mycelium, etc. For example, it is believed that a glutamic acid content of about 30 mg / g or about 40 mg / g can be obtained.

[0053] The protein content of the koji mold tissue product can be measured after drying (lyophilization, etc.) The measurement method can be the Kjeldahl method, which is well known to those skilled in the art. The koji mold tissue product preferably contains 15% to 70% by mass, more preferably 20% to 60% by mass, and even more preferably 25% to 55% by mass of protein relative to the total dry mass. As described above, by appropriately selecting the medium components or by performing culture with subsequent addition of the first nitrogen source, it is possible to obtain a koji mold tissue product containing 30% or more by mass, 35% or more by mass, or even 40% or more by mass of protein. A koji mold tissue product containing 30% or more by mass of protein can be used as an alternative protein source.

[0054] The koji mold tissue product obtained by the production method of the present invention may contain components derived from the medium components used in culturing koji mold. The content of these components usually decreases when the mycelium is washed with purified water or the like after culturing, compared to the content of the mycelium immediately after culturing. For example, a koji mold tissue product with enhanced functionality can be provided by adding functional components to the medium components used in culturing and providing the final product without a washing step.

[0055] The koji mold tissue product obtained by the production method of the present invention can be used as a functional food. Furthermore, the koji mold tissue product, which is rich in protein, can be used as an alternative protein source. The koji mold tissue product may be adjusted to a water content (for example, 60% to 95% by mass) according to the intended use. As with general food ingredients, auxiliary ingredients may be added or physicochemical processing operations may be performed according to the intended use to achieve the desired taste, flavor, texture, etc. Koji mold tissue products can be distributed as fresh food. They can also be stored until the time of use or processing. Koji mold tissue products can also be frozen or dried (lyophilized, etc.) for storage and distribution.

[0056] It is necessary to prevent deterioration of koji mold tissue products over time, such as oxidation and microbial putrefaction, and after mycelium production, it is necessary to process them in a stable state for distribution, etc. For this purpose, mycelium produced by culture is generally immediately separated and recovered from the medium and then immediately subjected to freezing or high-temperature sterilization, etc. In the present invention, for example, a standing step is provided after the above-mentioned mycelium is separated and recovered, thereby improving the taste and texture. After the standing is completed, it is preferable to immediately perform freezing or high-temperature sterilization, etc. If koji mold tissue is frozen, subsequent freeze-drying, which sublimates the water, allows for even more stable long-term storage. If sterilized at high temperatures, it can be packed under sterile conditions and vacuumed, allowing for stable long-term storage even at room temperature. Freezing and high-temperature treatments prevent oxidation and spoilage and prevent changes in the components caused by enzyme reactions in koji mold, making long-term storage possible.

[0057] The koji mold tissue product obtained by the production method of the present invention can be used for food. For example, koji mold tissue products with a high protein content can be cooked as a meat substitute as is in the same way as regular meat, or can be mixed with meat, eggs, egg white, other meat substitute materials, and the like and cooked. Furthermore, koji mold tissue products can be used, for example, as a dried powder, by adding them to various foods and beverages. Koji mold tissue products provided as foods may further contain seasonings such as salt, sugar, soy sauce, miso, and alcoholic beverages, spices, sweeteners, preservatives, emulsifiers, flavorings, and the like. These ingredients can be mixed, for example, with the koji mold tissue product obtained after the standing period is complete or with the dried powder obtained by drying it.

[0058] Furthermore, the koji mold tissue product can also be used as a feed additive to be incorporated into feed for livestock, poultry, and seafood. [Example]

[0059] The present invention will be described in more detail below with reference to examples. The materials, reagents, amounts and proportions of substances, procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following examples.

[0060] In the examples, the koji mold used as a culture starter was Aspergillus oryzae RIB40 strain, which was obtained from the NITE Biological Resource Center. The bacteria were inoculated onto PDA medium and cultured at 30°C for one week to allow spores to adhere to the plate surface. Sterilized 0.05% Tween 20 solution was poured onto the plate, and the surface was rubbed to remove the spores, yielding a spore suspension. The spore concentration of the spore suspension was measured using a hemocytometer, and the suspension was diluted appropriately for use.

[0061] (1) Preparation of liquid medium The yeast extract and glucose used were both commercially available products used as medium components for microbial culture. The medium components shown in each example were weighed out in predetermined amounts, for example, into a 2.8 L Erlenmeyer flask, and 1500 mL of distilled water was added. The flask was then fitted with a lid fitted with a breathable filter and sterilized in an autoclave (121°C, 15 minutes).

[0062] (2) Cultivation in liquid medium After the liquid medium was sterilized in an autoclave and cooled thoroughly, it was inoculated with bacteria in a clean bench. 7 ~1.0×10 8 / mL spore suspension was used, resulting in a final spore concentration of 1.0 × 10 4 After the addition of the spore suspension, the mixture was placed in an incubator shaker (Innova S44i, manufactured by Eppendorf), and the incubator was set to 30°C and cultured by rotation at 180 rpm for 3 days.

[0063] (3) Method for collecting mycelium After the cultivation was completed, the cultivated bacterial solids were separated from the culture solution. The culture solution containing the bacterial cells was poured into a Buchner funnel equipped with a filter paper or a filter, and the water was efficiently removed using a suction pump. The collected mycelium was washed with an appropriate amount of pure water so as not to affect the bacterial component values. If necessary, the collected bacterial cells were frozen and stored, and then returned to room temperature before use.

[0064] In a koji mold culture experiment conducted separately from the examples below, the free amino acids in samples prepared by freeze-drying the washed mycelia were measured, and the contents of 16 major amino acids, including glutamic acid, were found to be in the range of 10 mg / 100 g to 350 mg / 100 g. Comparing the results of a freeze-dried sample of a cultured composition consisting of the solid mycelia and culture solution before washing with the results of a freeze-dried sample, the amino acid contents were all reduced, indicating that amino acids derived from the culture solution (medium) had been removed and amino acids within the mycelia had been measured. From these results, it can be understood that the results of Examples 1 to 4 below, in which the amino acid amounts were measured in mycelia after washing, reflect the amino acid contents in the mycelia.

[0065] (4) Allowing the mycelium to stand The wet weight of the obtained mycelium was recorded, and the mycelium was cut into a plurality of tissue pieces with a knife or the like so that each piece was approximately the same shape and mass, between 5 and 10 g, and then subjected to a maturation treatment (standing still). Within the temperature range (0°C to 60°C) where enzymes such as proteases are thought to be active, but where koji mold does not grow, the mycelium was placed in a container that did not block oxygen and left to stand in an incubator for a specified time to reach the specified temperature. After standing, the sample was transferred to a freezer at -20°C or below, frozen, and stored until measurement. For the aging treatment using vacuum packs, the samples were sealed at a 95% vacuum using a vacuum packing machine (TOSPACK, TOSEI Corporation). They were stored in a thermostatic chamber at 20°C for 7 days. After leaving the samples, they were immediately transferred to a freezer at -20°C or below, frozen, and stored until the time of measurement.

[0066] (5) Method for measuring the free glutamic acid content of koji mold tissue To prepare the measurement sample, frozen koji mold tissue was first freeze-dried to obtain dried mycelia. Purified water was added to the tube to a concentration of 10 mg / ml. Glass beads were added to the tube, and the mycelia were disrupted using a bead-type disrupter (FastPrep24: MP Biomedicals). The tube was then centrifuged at 12,000 rpm for 3 minutes, and the supernatant was transferred to a separate tube as the measurement sample. Glutamate levels were measured using a glutamate measurement kit (Enzyme Sensor Co., Ltd.) according to the protocol.

[0067] (6) Method for measuring the free amino acid content of koji mold tissue To prepare the measurement samples, frozen koji mold tissue was freeze-dried to obtain dried fungal cells. The freeze-dried fungal cells were crushed in a mortar, and extracted with 0.1% 2-mercaptoethanol and trichloroacetic acid at 4°C for 3 hours. After centrifugation at 10,000 × g for 20 minutes, 2.5 M lithium hydroxide was added to adjust the pH to within the range of 2-3. The mixture was filtered through a 0.45 μm filter and analyzed using a high-speed amino acid analyzer (Hitachi High-Tech Science, LA8080).

[0068] [Example 1] Aspergillus oryzae was cultured in YG liquid medium containing 1% yeast extract and 2% glucose at 30°C for 3 days, washed with pure water, and then dehydrated to obtain mycelia. The mycelia were dissected as described above and stored at 4°C for 1, 3, 5, 7, or 9 days to obtain koji mold tissues. After storage, the samples were frozen and freeze-dried, and the glutamic acid content was measured. The results are shown in Figure 1. Compared to the untreated sample, all samples treated for 1 day or more had significantly higher glutamic acid content. In Figure 1, "untreated" indicates the results for samples that were not stored for the above period. Compared to the untreated sample, the sample stored for 1 day showed an increase in glutamic acid content, and the sample stored for 3 days showed a further increase. The increase was similar for samples stored for 3 to 9 days.

[0069] [Example 2] Aspergillus oryzae was cultured in YG liquid medium containing 1% yeast extract and 2% glucose at 30°C for 3 days, washed with pure water, and then dehydrated to obtain mycelium. The mycelium was cut as described above and stored at 4°C, 10°C, and 45°C for 1, 2, and 3 days, respectively, to obtain koji mold tissues. After storage, the samples were frozen and freeze-dried, and the glutamic acid content was measured. The results are shown in Figure 2. At all temperatures, the glutamic acid content of all samples treated for 1 day or longer was significantly higher than that of untreated samples.

[0070] [Example 3] Aspergillus oryzae was cultured in YG liquid medium containing 1% yeast extract and 2% glucose at 30°C for 3 days, washed with pure water, and then dehydrated to obtain mycelia. The mycelia were then cut as described above and stored at 4°C for 7 days to obtain koji mold tissues. After storage, the samples were frozen and lyophilized, and the free amino acid content was measured. The results are shown in Figure 3. Compared to the untreated sample, the 7-day treated sample exhibited significantly increased levels of glutamic acid, as well as other proteinogenic amino acids, including aspartic acid, threonine, serine, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine. Furthermore, the content of the functional amino acid ornithine was also increased.

[0071] [Example 4] Aspergillus oryzae was cultured in YG liquid medium containing 1% yeast extract and 2% glucose at 30°C for 3 days, washed with pure water, and then dehydrated to obtain mycelia. The mycelia were then cut as described above and vacuum-packed and stored at 4°C and 20°C for 7 days to obtain koji mold tissues. After storage, the samples were frozen and lyophilized, and the free amino acid content was measured. The results are shown in Figure 4. Compared to the untreated sample, the vacuum-packed sample stored at 20°C for 7 days exhibited significantly increased levels of glutamic acid, as well as other proteinogenic amino acids, including aspartic acid, threonine, serine, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine. The functional amino acids GABA and ornithine were also increased.

[0072] [Example 5] Aspergillus oryzae was cultured in YG liquid medium containing 1% yeast extract and 2% glucose for 3 days and then harvested by suction filtration under a sterile environment. After harvesting, the mycelium was shredded into 1 cm pieces and sealed under a 95% vacuum using a vacuum packing machine (TOSPACK, TOSEI Corporation). The mycelium was then left to stand in an incubator at 4°C or 20°C for 1, 3, or 5 days, respectively. After standing, the mycelium was removed from the vacuum pack and its hardness (N) was measured using a texture analyzer (EZTest, Shimadzu Corporation). A blade attachment was used to cut the mycelium at a speed of 2 mm / s, and the maximum resistance force when cutting the mycelium was defined as hardness. The results are shown in Figure 5. Figure 5 indicates that the mycelium softened during the standing process.

[0073] [Example 6] Aspergillus oryzae was cultured in liquid medium containing 1% yeast extract and 2% glucose. The cells were harvested by suction filtration and stored at -20°C until the test date. To examine the effect of the number of days in culture on enzyme activity, the protease activity of cells cultured for 1 to 4 days using the above method was measured. The cells were freeze-dried, and the enzyme was extracted using phosphate buffer (pH 7) to obtain an enzyme solution. The solution was then reacted with casein solution (substrate). The liberated tyrosine was colored with a phenol reagent, and the absorbance was measured to calculate and evaluate the enzyme activity. The results are shown in Figure 6. Figure 6 indicates that the number of days in culture did not affect the protease activity.

[0074] <Other culture methods> In the production method of the present invention, the method for culturing koji mold to obtain mycelia is not limited to the culture methods in the above examples, and various culture methods can be used. Below, an example is shown in which a culture method capable of obtaining mycelia with a higher protein content was investigated.

[0075] (1) Preparation of liquid medium The yeast extract, casamino acids, and peptones used were all commercially available products used as medium components for microbial culture. The sake lees used were from Kikuya Oita Co., Ltd., and the raw sugar used was low-refined sugar (raw sugar) made from 100% sugarcane. Brown rice flour was from Ishizaka Farm. The medium components shown in each example (components added from the start of culture) were weighed in predetermined amounts into, for example, a 200 mL Erlenmeyer flask, and 50 mL of distilled water was added. The flask was then sealed with a silicone stopper and sterilized in an autoclave (121°C, 15 minutes). When a first nitrogen source was added from the start of culture, the first nitrogen source was added to the concentration described in the description of each example (0.25%, 0.5%, 1%, 2%) before the autoclave sterilization. When adding the first nitrogen source later, 2.5%, 5%, and 10% solutions of the first nitrogen source were prepared in advance, sterilized in an autoclave, and cooled. At the designated time points, 5.5 mL of this concentrated solution was added to the original medium to adjust the final concentrations to approximately 0.25%, 0.5%, and 1%, respectively, and the culture was continued.

[0076] (2) Cultivation in liquid medium After the liquid medium was sterilized in an autoclave and cooled thoroughly, it was inoculated with bacteria in a clean bench. 7 Use 50 µL of the spore suspension at 100 µL / mL, resulting in a final spore concentration of 5.0 x 10 4 The spore suspension was added at a volume of 1 / mL. After addition, the flask was placed in a shaker (MMS-1020, manufactured by Tokyo Rikakikai Co., Ltd.) installed in an incubator (FMC-1000, manufactured by Tokyo Rikakikai Co., Ltd.), and the incubator was set to 30°C and cultured at 120 rpm for 3 days. When the first nitrogen source was to be added later, the flask was removed from the culture and, in a sterile space such as a clean bench, the lid was opened and a solution of the first nitrogen source at a predetermined concentration was added. After the addition, the lid was replaced, and the culture was continued in the incubator.

[0077] (3) Method for collecting cultured mycelium After the cultivation was completed, the obtained mycelium (solid mycelium) was separated from the culture solution. The culture solution containing the cultivated mycelium was poured into a funnel equipped with filter paper, and the water was efficiently removed using a suction pump. The collected mycelium was washed with an appropriate amount of pure water so as not to affect the values ​​of the mycelium components. The wet weight of the cultivated mycelium obtained was recorded, and the mycelium was stored frozen until it was used for measurement.

[0078] [Example 1R] At the start of cultivation, yeast extract was added to a liquid medium containing 2% sake lees and 2% raw sugar, or a liquid medium containing 2% brown rice flour, and the protein content of the resulting mycelium was confirmed. Yeast extract was added to the liquid medium from the start of cultivation. The results are shown in Figure 7. In both cases, the addition of 1% yeast extract significantly increased the protein content.

[0079] [Example 2R] We investigated the differences in protein content of mycelia obtained by adding different amounts of yeast extract to a liquid medium containing 2% sake lees and 2% raw sugar at the start of cultivation. Yeast extract was added to the liquid medium from the start of cultivation. The results are shown in Figure 8. When the yeast extract was increased from 1% to 2%, no significant increase in protein content was observed, indicating that the threshold protein content could be achieved by adding approximately 1% yeast extract.

[0080] [Example 3R] We investigated the difference in protein content of mycelia obtained by adding 1% or 2% yeast extract to liquid medium containing 2% or 4% raw sugar at the start of cultivation. Yeast extract was added to the liquid medium from the start of cultivation. The results are shown in Figure 9. No significant increase in protein content was observed when the yeast extract concentration was increased from 1% to 2%, indicating that even in liquid medium containing only raw sugar as a carbon source, the threshold protein content can be roughly achieved by adding approximately 1% yeast extract. Furthermore, no significant increase in protein content was observed when the raw sugar concentration was increased from 2% to 4%.

[0081] [Example 4R] We investigated the difference in protein content of the resulting mycelium when casamino acids or peptone was added to a liquid medium containing 2% sake lees and 2% raw sugar at the start of cultivation. Casamino acids or peptone were added to the liquid medium from the start of cultivation. The results are shown in Figure 10. The addition of 1% casamino acids or peptone significantly increased the protein content.

[0082] [Example 5R] The wet weight and protein content of the mycelia obtained when 1% yeast extract or 1% casamino acids was added to a liquid medium containing 2% sake lees and 2% raw sugar at the start of cultivation, 24 hours or 4 hours before harvesting the mycelia, were examined. The results (average values ​​of two samples) are shown in Figure 11. In either case, the protein content was significantly higher in the mycelia obtained from the cultivation in which yeast extract or casamino acids was added 24 hours before than in the cultivation in which it was added 4 hours before.

[0083] [Example 6R] The wet weight and protein content of mycelia were measured when yeast extract was added to a liquid medium containing 2% sake lees and 2% raw sugar at the start of cultivation. The results are shown in Figure 12. In Figure 12, YE stands for yeast extract.

[0084] The wet weight of the mycelium obtained from the culture without yeast extract was 1.036 g, and the protein content was 25.9%. On the other hand, the mycelium obtained from the culture with yeast extract added at 0.25%, 0.5%, and 1% also increased in wet weight, and the protein contents were 33.1%, 41.8%, and 46.1%, respectively. All of the protein contents were higher than those of the mycelium obtained from the culture without yeast extract.

[0085] As an example of post-addition, culture was initiated in a liquid medium containing 2% sake lees and 2% raw sugar. Two days after the start of culture (24 hours before harvesting), 5.5 mL of water or 5.5 mL of yeast extract solution was added to adjust the yeast extract concentration in the liquid medium to 0%, 0.25%, 0.5%, or 1%, and culture was continued. The protein contents of the resulting mycelia were 26.4%, 40.6%, 45.5%, and 48.9%, respectively. Compared to the mycelia obtained from cultures supplemented with water, the protein content of the mycelia obtained from cultures supplemented with yeast extract was significantly higher.

[0086] When the same amount of yeast extract was used, the protein content of the mycelia obtained from the culture in which the yeast extract was added from the start of the culture was compared with that obtained from the culture in which the yeast extract was added 24 hours before harvesting, as shown below. With 0.25% yeast extract: 33.1% for initial addition and 40.6% for later addition; With 0.5% yeast extract: 41.8% for initial addition and 45.5% for later addition; With 1% yeast extract: 46.1% for initial addition and 48.9% for later addition. These results show that the effect of increasing the protein content by post-addition is more pronounced in mycelia obtained by culturing in a liquid medium to which yeast extract has been added at a concentration of 0.5% or less.

[0087] [Example 7R] At the start of cultivation, the liquid medium contained 2% sake lees and 2% raw sugar, and the wet weight and protein content of the mycelium obtained by adding yeast extract at different times were compared. The results are shown in Figure 13. In Figure 13, YE represents yeast extract. When yeast extract was added to a concentration of 0.25% or 0.5%, adding it on the second day after the start of cultivation (24 hours before harvesting) had the greatest effect on increasing protein content, and adding it between the first day (48 hours before harvesting) and 16 hours before harvesting was also effective. [Industrial Applicability]

[0088] The method for producing a koji mold tissue product of the present invention can provide a koji mold tissue product suitable for consumption. The production method of the present invention includes a standing step, which can increase the amino acid content of glutamic acid and other such products in the koji mold tissue product produced. Therefore, the koji mold tissue product produced by the production method of the present invention can be used as a meat substitute or the like with better taste and texture.

Claims

1. A method for producing a koji mold tissue product, comprising allowing mycelium of koji mold to stand in an environment of 0°C to 60°C under conditions in which the koji mold does not grow.

2. The production method according to claim 1, wherein the standing is carried out under conditions that satisfy at least one of the following (a) and (b): (a) anaerobic conditions; (b) Temperature conditions below 20°C or above 40°C.

3. The method according to claim 1, wherein the standing is carried out for 1 to 20 days.

4. The production method according to claim 1, which satisfies any one of the following (a-1), (b-1), and (b-2): (a-1) The mycelium is vacuum-packed, and the standing is performed at room temperature; (b-1) The standing is carried out at 2 to 18°C; (b-2) The standing is carried out at 42 to 50°C.

5. The method according to claim 4, which satisfies (a-1).

6. The method according to any one of claims 1 to 5, comprising obtaining the mycelium by culturing.

7. The method according to claim 6, wherein the leaving is carried out after the cultured mycelium is collected.

8. The method according to claim 7, wherein the mycelium is frozen, dried, lyophilized, or sterilized at high temperature 1 to 20 days after the harvesting.

9. The method according to claim 6, wherein the culturing is performed in a liquid medium.

10. The method according to claim 6, wherein the mycelium is obtained by culturing the following ingredients (1) to (3) in this order: (1) Initiating the cultivation of a starter koji mold in a liquid medium containing at least a carbon source; (2) adding a first nitrogen source to the liquid medium after the koji mold starts to grow in the liquid medium; and (3) After the addition of the first nitrogen source, the culture is continued for the time required for the production of a protein using the first nitrogen source as a raw material.

11. A koji mold tissue product containing koji mold mycelium, the koji mold tissue product contains at least three amino acids selected from the group consisting of aspartic acid, threonine, serine, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine, each of which is contained in an amount of 10 mg / g or more relative to the total dry mass of the koji mold tissue product; A koji mold tissue product in which all of the three amino acids are present inside the mycelium.

12. The koji mold tissue product according to claim 11, which is edible.

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