Method for producing mushroom, culture medium base material for mushroom, and culture medium composition for mushroom

Abstract

To provide a method for producing a mushroom that achieves superior economic performance and allows production of a mushroom having an increased amino acid content.SOLUTION: A method for producing a mushroom, the method comprising cultivating a mushroom using a culture medium composition for mushroom containing formic acid-treated moist tea leaves or a culture medium composition for mushroom containing anaerobically fermented moist tea leaves.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a method for producing mushrooms, a medium substrate for mushrooms, and a medium composition for mushrooms. [Background technology]

[0002] Mushroom cultivation methods can be broadly divided into log cultivation, wood flour cultivation, and compost cultivation. For example, wood flour cultivation is a method of cultivating mushrooms such as shiitake, oyster mushroom, enoki mushroom, maitake, and buna-shimeji mushroom using a medium containing wood flour as the main component (see, for example, Patent Document 1). In recent years, as the prices of raw materials for medium have tended to rise, there is a demand for providing mushrooms at a stable production price. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-244821 Summary of the Invention [Problem to be solved by the invention]

[0004] One method proposed for reducing mushroom production costs is a cultivation method that uses inexpensive materials, such as agricultural or food by-products, as culture medium raw materials. However, there is concern that the nutritional content of mushrooms may be reduced depending on the materials used. In recent years, there has been a demand for mushrooms with added value, such as mushrooms with high nutritional value, and there is a need for culture medium raw materials that can cultivate mushrooms with high nutritional content while reducing production costs.

[0005] Therefore, an object of one embodiment of the present invention is to provide a method for producing mushrooms that is economical and allows the production of mushrooms with an increased amino acid content.An object of another embodiment of the present invention is to provide a mushroom culture medium base and a mushroom culture medium composition that are economical and allow the production of mushrooms with an increased amino acid content. [Means for solving the problem]

[0006] The inventors of the present invention have discovered that by using hydrated tea leaves that have been treated with formic acid or anaerobically fermented as a medium substrate for mushrooms, it is possible to increase the amino acid content while reducing the cost of the medium substrate.

[0007] The present invention includes the following embodiments, but is not limited to the following embodiments. (1) A method for producing mushrooms, comprising cultivating mushrooms using a mushroom medium composition containing hydrated tea leaves treated with formic acid. (2) A method for producing mushrooms, comprising cultivating mushrooms using a mushroom medium composition containing anaerobically fermented hydrated tea leaves. (3) A method for producing mushrooms according to (1) or (2) above, which produces mushrooms with increased amino acid content. (4) The method for producing mushrooms according to (2) or (3) above, wherein the anaerobic fermentation is lactic acid fermentation.

[0008] (5) A mushroom culture medium substrate containing hydrated tea leaves that have been treated with formic acid or anaerobically fermented. (6) The mushroom culture medium base material according to (5) above, wherein the moisture content of the hydrated used tea leaves is 50 to 80% by mass. (7) A mushroom medium composition containing at least one selected from the group consisting of wood flour, rice bran, and corncob meal, and formic acid-treated or anaerobically fermented hydrated tea leaves. (8) The mushroom medium composition according to (7) above, wherein the content of the hydrated tea leaves is 1 to 15% by mass based on the dry mass. [Effects of the Invention]

[0009] According to one embodiment of the present invention, there is provided a method for producing mushrooms that is economical and allows the production of mushrooms with an increased amino acid content. According to another embodiment of the present invention, there are provided a mushroom culture medium base and a mushroom culture medium composition that are economical and allow the production of mushrooms with an increased amino acid content. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments.

[0011] [Mushroom culture medium substrate] In an embodiment of the present invention, the mushroom culture medium substrate contains hydrated tea leaves that have been treated with formic acid or anaerobically fermented. The hydrated tea leaves that have been treated with formic acid or anaerobically fermented may be hydrated tea leaves that have been treated with formic acid, hydrated tea leaves that have been anaerobically fermented, hydrated tea leaves that have been treated with formic acid and anaerobically fermented, or a mixture of two or more of these. The mushroom culture medium substrate is used for cultivating mushrooms either as is or mixed with a substrate or nutrient material such as wood flour, rice bran, or corncob meal. Examples of mushrooms include Bunashimeji mushrooms, Enoki mushrooms, Honshimeji mushrooms, Oyster mushrooms, Maitake mushrooms, Shiitake mushrooms, King oyster mushrooms, Nameko mushrooms, mushrooms, and Wood ear mushrooms. The mushroom culture medium substrate is preferably used for Bunashimeji mushrooms and Enoki mushrooms.

[0012] A mushroom culture medium substrate containing formic acid-treated hydrated tea leaves can be produced by treating tea leaves with formic acid. A mushroom culture medium substrate containing anaerobically fermented hydrated tea leaves can be produced by fermenting tea leaves under anaerobic conditions. Hydrated tea leaves that have been subjected to formic acid treatment and anaerobic fermentation can be produced by treating tea leaves with formic acid and then further anaerobic fermentation. The tea leaves used for the formic acid treatment or anaerobic fermentation may be hydrated tea leaves or dried tea leaves, and hydrated tea leaves are preferred because the hydrated tea leaves recovered after extraction of tea components can be used without a drying process.

[0013] Used tea leaves are the residue containing leaves and stems after tea components are extracted from raw tea with water. In this specification, "raw tea" includes tea plant tissue containing active ingredients that can be extracted as tea, specifically including leaves and stems. The raw tea may be unfermented tea, semi-fermented tea, fermented tea, or a mixture thereof. An example of unfermented tea is green tea, an example of semi-fermented tea is oolong tea, and an example of fermented tea is black tea. The raw tea is preferably green tea, and examples of green tea include steamed tea, sencha, gyokuro, bancha, tamaryokucha, kamaikecha, tencha, and matcha. The green tea may be domestically or internationally produced. The raw tea may be a single type of raw tea, or a mixed raw tea containing two or more types of raw tea.

[0014] The used tea leaves contain leaves and stems in a mass ratio (dry mass ratio) of preferably 20:80 to 80:20, more preferably 30:70 to 70:30. Used tea leaves obtained without adjusting the mass ratio of leaves to stems can be used. Alternatively, since the ratio of leaves to stems varies depending on the tea harvest time, harvest year, type of raw tea, and intended use, used tea leaves may be adjusted so that the leaf to stem content meets the above mass ratio in order to provide a stable mushroom medium substrate. When the mass ratio of leaves to stems is within the above range, mushrooms tend to grow well.

[0015] An example of a method for treating used tea leaves with formic acid is mixing the hydrated used tea leaves with formic acid. Mixing can be performed at room temperature (e.g., 25°C). "Hydrated used tea leaves treated with formic acid" may contain water, used tea leaves and components derived from the used tea leaves, as well as formic acid and components derived from formic acid. "Hydrated used tea leaves treated with formic acid" has a lower pH than hydrated used tea leaves not treated with formic acid. The amount of formic acid to be mixed may be 0.01 to 4.0% by mass, more preferably 0.06 to 1.4% by mass, based on the dry mass of the used tea leaves contained in the hydrated used tea leaves.

[0016] When mixing the hydrated used tea leaves with formic acid, formic acid may be used alone, or an aqueous formic acid solution or a commercially available formic acid additive may be used.

[0017] An example of a method for fermenting used tea leaves under anaerobic conditions is a method in which hydrated used tea leaves are mixed with lactic acid bacteria and the used tea leaves are subjected to lactic acid fermentation under anaerobic conditions. Lactic acid fermentation can be carried out at 20 to 50°C, preferably 25 to 37°C. "Anaerobically fermented used tea leaves" may contain water, used tea leaves and components derived from used tea leaves, lactic acid bacteria, and lactic acid. The lactic acid content in "anaerobically fermented used tea leaves" is higher than the lactic acid content in used tea leaves that have not been subjected to anaerobically fermentation. Commercially available lactic acid bacteria agents can be used for lactic acid fermentation. The amount of lactic acid bacteria to be mixed can be adjusted appropriately depending on the number of bacteria in the lactic acid bacteria agent used, the storage period, etc. For example, when using a lactic acid bacteria agent for silage such as cyprolacto as the lactic acid bacteria, the amount of the lactic acid bacteria agent to be mixed may be 0.04 to 20 mass%, more preferably 0.06 to 4.0 mass%, and even more preferably 0.08 to 1.0 mass%, based on the dry mass of the tea leaves contained in the hydrated tea leaves.

[0018] Examples of lactic acid bacteria include lactic acid cocci such as Lactobacillus thermophilus, Lactobacillus lactis, and Lactobacillus cremoris; and Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus helveticus, and Lactobacillus casei. Examples of lactic acid bacterial cells include Lactobacillus genus, Bifidobacterium genus, Lactococcus genus, Pediococcus genus, Enterococcus genus, Streptococcus genus, and Leuconostoc genus. The lactic acid bacteria to be mixed with hydrated used tea leaves may be powdered or cultured, preferably powdered. The powdered lactic acid bacteria may be, for example, a freeze-dried powder.

[0019] When the tea leaves used in the formic acid treatment or anaerobic fermentation are hydrated tea leaves, the moisture content of the hydrated tea leaves ((mass (g) of water in hydrated tea leaves / mass (g) of hydrated tea leaves) × 100(%)) is preferably 50 to 80% by mass, more preferably 60 to 79% by mass, and even more preferably 70 to 78% by mass. When the moisture content is 50% by mass or more, the amount of moisture to be removed from the tea leaves after extraction can be reduced by using a dehydrator or the like without using fuel, thereby reducing the energy consumed in heat treatment using fuel, or eliminating the need for a large area for sun drying and saving time for drying. When the moisture content is 80% by mass or less, solid-liquid separation can be prevented from occurring during storage of the hydrated tea leaves, allowing the subsequent formic acid treatment or anaerobic fermentation to be carried out efficiently.

[0020] The moisture content of the hydrous tea leaves that have been treated with formic acid or anaerobic fermented ((mass (g) of water in hydrous tea leaves / mass (g) of hydrous tea leaves) × 100 (%)) is preferably 50 to 80 mass%, more preferably 60 to 79 mass%, and even more preferably 70 to 78 mass%. When the moisture content is 50 mass% or more, the amount of moisture that needs to be removed from the tea leaves after extraction can be reduced, which reduces the energy consumed in heat treatment using fuel, or eliminates the need for a large area for sun drying and saves time for drying. When the moisture content is 80 mass% or less, solid-liquid separation can be prevented from occurring during storage of the hydrous tea leaves, allowing the subsequent formic acid treatment or anaerobic fermentation to be carried out efficiently.

[0021] The pH of the formic acid-treated or anaerobically fermented hydrated tea leaves is preferably 3.5 to 7.0, more preferably 3.8 to 6.9, and even more preferably 3.9 to 6.0. A pH of 3.5 or higher can suppress adverse effects on mushroom growth. A pH of 7.0 or lower can prevent the proliferation of bacteria that adversely affect mushroom mycelia in the used tea leaves. In this specification, the pH of the hydrated used tea leaves may be the pH of a mixture of hydrated used tea leaves and distilled water in a weight ratio of 1:9, and can be measured using a pH meter. The pH meter is calibrated at three points using pH buffer solutions (pH = 4.0, 7.0, and 9.0). For example, measurements are performed five times using the pH meter, and the average of the five measurements is taken as the pH of the hydrated used tea leaves.

[0022] Formic acid-treated hydrated tea leaves and anaerobically fermented hydrated tea leaves may be mixed to prepare a mushroom medium substrate containing both. The formic acid-treated hydrated tea leaves may be further anaerobically fermented to prepare a mushroom medium substrate containing hydrated tea leaves that have been subjected to formic acid treatment and anaerobic fermentation. In this case, the formic acid treatment reduces the pH of the hydrated tea leaves, thereby suppressing spoilage of the tea leaves and facilitating anaerobic fermentation.

[0023] The mushroom culture medium substrate according to an embodiment of the present invention contains hydrated used tea leaves that have been treated with formic acid, hydrated used tea leaves that have been anaerobically fermented, hydrated used tea leaves that have been treated with formic acid and anaerobically fermented, or a mixture of two or more of these. The mushroom culture medium substrate can increase the amino acid content of mushrooms and enhance their concentration.

[0024] Furthermore, because the mushroom culture medium substrate according to an embodiment of the present invention utilizes used tea leaves, a food by-product, it is highly economical and leads to the effective use of unused resources. Generally, when using resources such as food by-products in mushroom culture media, there are concerns that the shape and size must be adjusted, that if the material is dried, the moisture content of the medium after preparation may be uneven, which may affect growth, or that if the material is highly hydrated, the drying process may require time and energy. Used tea leaves have a shape and size suitable for culture media, and when hydrated tea leaves recovered after extracting tea components are used, they contain an appropriate amount of moisture, making it easy to adjust the moisture content for use as a culture medium substrate.

[0025] [Mushroom medium composition] In an embodiment of the present invention, a mushroom medium composition contains at least one selected from the group consisting of wood flour, rice bran, and corncob meal, and formic acid-treated or anaerobically fermented hydrated tea leaves. The mushroom medium composition may contain wood flour, rice bran, and corncob meal, and formic acid-treated hydrated tea leaves or anaerobically fermented hydrated tea leaves. The mushroom medium composition is used as a medium for mushroom cultivation.

[0026] Examples of wood flour include sawdust from cedar, beech, oak, etc. The mushroom medium composition may contain any other component in addition to wood flour, rice bran, and corncob meal. The optional component may be, for example, a base material or nutrient material, such as soybean hulls, shochu lees, corn, corn bran, grain sorghum, bran, soybean lees, cotton hulls, etc. Commercially available medium activators may also be used, such as the medium activator "Nyokidel" (manufactured by Denka Co., Ltd.).

[0027] The content of hydrated tea leaves in the mushroom medium composition by dry mass ((dry mass (g) of tea leaves / mass (g) of mushroom medium composition excluding water) × 100(%)) is preferably 1 to 15 mass%, more preferably 1 to 14 mass%, and even more preferably 1 to 13 mass%. When the content is 1 mass% or more, an increase in the amount of amino acids can be expected. When the content is 15 mass% or less, mushrooms tend to grow well.

[0028] When the mushroom medium composition contains wood flour, the content of wood flour in the mushroom medium composition by dry mass ((dry mass of wood flour (g) / mass of mushroom medium composition excluding water (g)) x 100 (%)) is preferably 20 to 75 mass%, more preferably 25 to 60 mass%, and even more preferably 25 to 45 mass%.

[0029] When the mushroom medium composition contains rice bran, the content of rice bran in the mushroom medium composition by dry mass ((dry mass (g) of rice bran / mass (g) of mushroom medium composition excluding water) × 100 (%)) is preferably 5 to 50 mass%, more preferably 10 to 45 mass%, and even more preferably 15 to 40 mass%.

[0030] When the mushroom medium composition contains corncob meal, the content of corncob meal in the mushroom medium composition by dry mass ((dry mass (g) of corncob meal / mass (g) of mushroom medium composition excluding water) × 100 (%)) is preferably 5 to 60 mass%, more preferably 5 to 50 mass%, and even more preferably 5 to 45 mass%.

[0031] The method for producing the composition is not particularly limited. It is sufficient to mix a mushroom medium base material with at least one selected from the group consisting of wood flour, rice bran, and corncob meal, and, if necessary, optional components such as base materials and nutrients. Mixing can be performed at room temperature (e.g., 25°C).

[0032] [Mushroom production method] In an embodiment of the present invention, the method for producing mushrooms comprises cultivating mushrooms using a mushroom medium composition containing formic acid-treated hydrated tea leaves or a mushroom medium composition containing anaerobically fermented hydrated tea leaves. The method for producing mushrooms may also use a mushroom medium composition containing both formic acid-treated hydrated tea leaves and anaerobically fermented hydrated tea leaves. The formic acid-treated hydrated tea leaves and anaerobically fermented hydrated tea leaves may each be tea leaves that have been subjected to both formic acid treatment and anaerobic fermentation. For example, the method for producing mushrooms comprises cultivating mushrooms using a mushroom medium composition containing formic acid-treated and then anaerobically fermented hydrated tea leaves.

[0033] In the mushroom production method, a mushroom medium composition is used as a medium. The mushroom production method can follow general mushroom production methods except for using a mushroom medium composition. The mushroom production method includes, for example, (1) preparing a mushroom medium composition, (2) filling a container with the mushroom medium composition, (3) sterilizing the mushroom medium composition, (4) inoculating the mushroom medium composition with a seed culture, (5) culturing mushrooms, (6) scraping, (7) sprouting and growing, and (8) harvesting the mushrooms.

[0034] The amino acid content of mushrooms can be increased by using a mushroom medium composition containing formic acid-treated hydrated tea leaves or a mushroom medium composition containing anaerobically fermented hydrated tea leaves as a culture medium. The mushroom production method may be a method for producing mushrooms with an increased amino acid content. As used herein, "mushrooms with an increased amino acid content" refers to mushrooms with an increased amino acid content compared to mushrooms produced under the same conditions using a culture medium that does not contain any of formic acid-treated hydrated tea leaves, anaerobically fermented hydrated tea leaves, or hydrated tea leaves that have been treated with formic acid and anaerobic fermentation.

[0035] In the production of Bunashimeji mushrooms, (5) the fungus is cultured for approximately 70 days in the dark at a temperature of 20-23°C and a humidity of 50-80%. (7) The fungus is cultured for approximately 10 days at a temperature of 14-16°C and a humidity of 95-100% to form fruiting body primordia and allow them to sprout. The fungus is then grown for approximately 2 weeks under an illumination intensity of 1500 lux (12 hours / day).

[0036] In the production of Enoki mushrooms, (5) involves cultivating and aging the fungus for 24 days in the dark at a temperature of 15-18°C and a humidity of 50-80%. (7) involves cultivating the fungus for approximately 10 days at a temperature of 17-19°C and a humidity of 50-80%, allowing the formation of fruiting body primordia and germination. The fungus is then allowed to acclimate for 3-5 days at a temperature of 5-6°C and a humidity of approximately 80%, and then inhibited for approximately 5 days under an illumination intensity of 1500 lux (30 minutes / day). After wrapping the fungus in paper, it is grown for approximately 7 days. [Example]

[0037] The embodiments of the present invention will be described below with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0038] [Example 1] (Preparation of mushroom medium substrate containing formic acid-treated hydrated tea leaves) Green tea residue (leaves:stems = 70:30) immediately after extraction discharged from a beverage factory was dehydrated using a screw press and allowed to cool, yielding hydrated used tea leaves with a moisture content of 75% by mass, pH 5.5, and a temperature of 40°C or less. 150 mg of formic acid additive (Nacalai Tesque, Inc., formic acid (purity 85% by mass)) was added to the hydrated used tea leaves per 100 g of hydrated used tea leaves and mixed to obtain a medium substrate for mushrooms. The pH of the hydrated used tea leaves (mushroom medium substrate) after formic acid treatment was 4.2.

[0039] (Preparation of mushroom medium substrate containing anaerobically fermented hydrated tea leaves) Freshly extracted green tea residue (leaves:stem = 70:30) discharged from a beverage factory was dehydrated using a screw press and allowed to cool, yielding hydrated used tea leaves with a moisture content of 75% by mass, pH 5.5, and a temperature of less than 40°C. Lactic acid bacteria powder (manufactured by the National Federation of Dairy Cooperative Associations, product name: Cyprolacto, lactic acid bacteria species: Lactobacillus casei and Streptococcus lactis) was sprinkled onto the hydrated used tea leaves at a rate of 50 mg per 100 g of hydrated used tea leaves and mixed. The mixture was placed in a 900 x 1000 mm, 0.07 mm thick polyethylene film bag (90 L commercial-use plastic bag, manufactured by Nippon Sanipak Co., Ltd.), degassed using a commercially available vacuum cleaner, sealed with cable ties, and stored at room temperature (25°C) for 30 days to obtain a mushroom medium substrate. The pH of the hydrated used tea leaves (mushroom medium substrate) after anaerobic treatment was 4.2.

[0040] (Preparation of mushroom medium composition) Mushroom medium compositions A to C were prepared by mixing a mushroom medium base material, cedar sawdust, rice bran, corncob meal, wheat bran, bean husks, cotton hulls, and a medium activator (Nyokidel, manufactured by Denka Co., Ltd.) in the mass ratios shown in Table 1.

[0041] [Table 1]

[0042] (Mushroom cultivation and evaluation) The mushroom medium composition was pressure-packed into an 850 mL plastic bottle. The bottled mushroom medium composition was then heat-sterilized at 120°C under saturated steam pressure. After cooling, the bottled mushroom medium composition was inoculated with Bunashimeji mushrooms (Nagano Agricultural and Industrial Research Institute B-4: Nagano Agricultural and Industrial Research Institute variety) in a sterile room. The mushrooms were then cultivated and aged for 70 days in the dark at a temperature of 20-23°C and a humidity of 50-80%. After cultivation and aging, the inoculum was scraped off (scraped), leaving an approximately 1 cm diameter inoculum in the center of the bottle neck. Water was poured onto the surface of the mushroom medium composition, and the inoculum was cultivated for 10 days at a temperature of 14-16°C and a humidity of 95-100% to form fruiting body primordia and germinate. Bunashimeji mushrooms were grown for 2 weeks under an illumination intensity of 1500 lux (12 hours / day). After two weeks of cultivation, the growth of the Bunashimeji mushrooms was completed, and the Bunashimeji mushrooms were harvested and the amino acid content of the fruiting bodies was analyzed according to the method described below. The evaluation results are shown in Table 2.

[0043] [Table 2]

[0044] [Example 2] (Preparation of mushroom medium composition) Mushroom medium composition D was prepared by mixing 176 g of a commercially available medium mainly containing corncob meal with 16 g of the anaerobically fermented hydrated tea leaves prepared in Example 1. Also, 194 g of a commercially available medium mainly containing corncob meal was prepared as mushroom medium composition E.

[0045] (Mushroom cultivation and evaluation) The mushroom medium composition was pressure-packed into an 850 mL plastic bottle. The bottled mushroom medium composition was then heat-sterilized at 120°C under saturated steam pressure. After cooling, the bottled mushroom medium composition was inoculated with Enokitake mushroom (Nagano Agricultural and Industrial Research Institute GA12: Nagano Agricultural and Industrial Research Institute variety) spores in a sterile room and cultured for 24 days in the dark at a temperature of 15-18°C and a humidity of 50-80%. After culturing, the inoculum was scraped off the surface of the bottle neck (scraping), and water was poured onto the surface of the medium. The spores were then cultured for 10 days at a temperature of 17-19°C and a humidity of 50-80% to form fruiting body primordia and allow germination. The mixture was allowed to acclimate for 4 days at a temperature of 5-6°C and a humidity of approximately 80%, and then inhibited for 5 days at an illumination intensity of 1500 lux (30 minutes / day), after which it was wrapped in paper. The mushrooms were then grown for another 7 days. After 7 days of cultivation, the mushrooms were harvested and the amino acid content of the fruiting bodies was analyzed according to the method described below. The evaluation results are shown in Table 3.

[0046] [Table 3]

[0047] [Method for analyzing amino acid content] The amount of amino acids was determined according to the following method. The harvested mushrooms were freeze-dried and pulverized in a ball mill. 200 mg of the pulverized material was weighed out and placed in a 100 mL volumetric flask. 80 mL of hot water was poured over the mixture, and the mixture was left to stand in an incubator at 80°C for 30 minutes to extract the amino acids. After standing for 30 minutes, the mixture was cooled to room temperature with cold water, and water was added to bring the volume to 100 mL. The mixture was then thoroughly shaken. The resulting liquid was used for high-performance liquid chromatography (HPLC) analysis. The amino acid content per dry mass (mg / 100 g) was determined using a Shimadzu NexeraX2 system with HPLC (fluorescence detection). The amino acids analyzed, the sample preparation method, and the HPLC conditions are described below.

[0048] Target amino acids: aspartic acid, glutamic acid, asparagine, serine, glutamine, histidine, glycine, threonine, arginine, alanine, GABA, tyrosine, cystine, valine, methionine, tryptophan, phenylalanine, isoleucine, leucine, lysine, proline

[0049] Sample preparation method: An appropriate amount of the liquid obtained above was measured out, suspended in distilled water, filtered, and then subjected to analysis. HPLC measurement conditions: Column: Shim-pack Velox C18 (3 mm x 100 mm) Temperature: 35℃ Mobile phase A: 14 mmol / L potassium dihydrogen phosphate and 4 mmol / L dipotassium hydrogen phosphate solution Mobile phase B: acetonitrile / methanol / ultrapure water = 30 / 40 / 30 (V / V / V) Detector: Fluorescence detector RF20-Axs Detection wavelength: Excitation 335nm, Emission 450nm

[0050] [Reference example] (Preparation of hydrated tea leaves) Green tea containing tea leaves and stems in the mass ratio shown in Table 4 was used as the raw material tea, and green tea components were extracted to obtain hydrated tea leaves a to d. Extraction was carried out by adding 10 g of green tea to 1 L of hot water at 90°C, at a green tea concentration of 10 g / L, at 90°C for 5 minutes. During the 5 minutes, stirring was carried out for 20 seconds at 0 minutes, 2 minutes, and 4 minutes after the addition of water. After 5 minutes of extraction, the extract and hydrated tea leaves were separated.

[0051] [Table 4]

[0052] (Mushroom production and evaluation) The hydrated used tea leaves were placed in a test tube, which was then placed in an autoclave bag to prevent moisture absorption, and sterilized in an autoclave (121°C, 20 minutes). Bunashimeji mushrooms (variety NN-12: Nagano Agricultural and Industrial Research Institute variety) were prepared and mycelia were inoculated into the hydrated used tea leaves. The mixture was then cultured for 12 days in an incubator set at 20°C. Five and 12 days after the start of culture, the amount of mycelial growth (mm) and growth rate (mm / day) were measured. The results are shown in Table 5.

[0053] The growth state of the mycelia was evaluated based on the following criteria, and the results are shown in Table 5. (Evaluation criteria) ◎ Mycelial growth of 20 mm or more over 12 days and mycelial growth rate of 2.0 mm / day or more over 12 days ○ Mycelial growth amount over 12 days is 20 mm or more, and mycelial growth rate over 12 days is less than 2.0 mm / day

[0054] [Table 5]

Claims

1. A method for producing mushrooms, comprising cultivating mushrooms using a mushroom medium composition containing hydrated tea leaves treated with formic acid.

2. A method for producing mushrooms, comprising cultivating mushrooms using a mushroom medium composition containing anaerobically fermented hydrated tea leaves.

3. 3. The method for producing mushrooms according to claim 1 or 2, wherein the mushrooms produced have an increased amino acid content.

4. The method for producing mushrooms according to claim 2 , wherein the anaerobic fermentation is lactic acid fermentation.

5. A mushroom culture medium base material containing hydrated tea leaves that have been treated with formic acid or fermented anaerobically.

6. The mushroom medium base material according to claim 5, wherein the moisture content of the hydrated tea leaves is 50 to 80% by mass.

7. A mushroom medium composition comprising at least one selected from the group consisting of wood flour, rice bran, and corncob meal, and formic acid-treated or anaerobically fermented hydrated tea leaves.

8. The mushroom medium composition according to claim 7, wherein the content of the hydrated tea leaves is 1 to 15% by mass based on dry mass.

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