A cultivation method for improving selenium content of auricularia auricula

Abstract

The application discloses a cultivation method for improving selenium content of Auricularia auricula, and comprises a cultivation material for improving selenium content of Auricularia auricula, wherein the cultivation material is obtained by mixing a slow-release sodium chlorate composite material and a slow-release selenium-containing mineral material with carbon nutrition, nitrogen nutrition and mineral nutrition respectively. In the application, the sodium chlorate and selenium are respectively prepared into specific slow-release systems, and the slow-release reaction in the cultivation material generates selenite which is easy to be absorbed and utilized by Auricularia auricula, so that the selenite concentration in the cultivation material is regulated, the growth of Auricularia auricula is promoted, the yield of Auricularia auricula is improved, the quality of Auricularia auricula is significantly improved, the selenium content and the amino acid content of Auricularia auricula are both significantly increased, and the cultivation material can be used for seedling cultivation of Auricularia auricula with high selenium content, so as to obtain high-quality seedlings of Auricularia auricula with high selenium content.

Description

[0001] This invention is a divisional application of patent application number 202411581354.X, entitled "A cultivation substrate for cultivating selenium-enriched black fungus and its preparation method". Technical Field

[0002] This invention relates to the field of edible fungi cultivation technology, specifically to a cultivation method for increasing the selenium content of black fungus. Background Technology

[0003] Selenium is a very small amount of trace element in the human body, but it is also an essential trace element. Its functions include: enhancing immunity, scavenging free radicals, and eliminating toxins from the body; selenium is an active component of glutathione peroxidase, preventing oxidative damage to insulin-producing beta cells and ensuring their normal function; enhancing and improving digestive and absorptive functions, promoting normal gastrointestinal function, and preventing constipation, bloating, abdominal pain, nausea, aversion to oily foods, and loss of appetite; selenium is an important element for maintaining normal heart function, protecting and repairing myocardial cells. Low blood selenium levels can lead to a decline in the body's ability to scavenge free radicals, resulting in the accumulation of harmful substances.

[0004] Black fungus, a precious edible and medicinal gelatinous fungus in my country, is recognized worldwide as a health food. It contains plant collagen, polysaccharides, and other substances. Dried black fungus varieties are high in protein, microorganisms, and iron. In recent years, with increased awareness of nutrition and health, research on selenium-enriched cultivation and the nutritional components of black fungus has become increasingly in-depth. However, the organic selenium content in the dried substrate of conventionally cultivated black fungus products has long been generally low. Adding a selenium source to the cultivation substrate can increase the selenium content of black fungus to some extent, but the following technical problems exist: If the selenium content is low, different selenium compounds will form in the substrate due to environmental changes, resulting in low effective absorption by the black fungus and less subsequent conversion into organic selenium. If a large amount of selenium source is introduced, the selenium content in the substrate will exceed the standard, leading to black fungus poisoning during growth, inhibiting growth, and ultimately reducing the yield and quality of black fungus. Summary of the Invention

[0005] Based on the above problems, the purpose of this invention is to provide a cultivation method for increasing the selenium content of black fungus, specifically a cultivation material for increasing the selenium content of black fungus.

[0006] Another objective of this invention is to provide a method for preparing the above-mentioned cultivation substrate for selenium-enriched black fungus.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A cultivation method for increasing the selenium content of black fungus includes a cultivation medium for increasing the selenium content of black fungus. The cultivation medium is characterized by: the cultivation medium being a mixture of slow-release sodium chlorate composite material and slow-release selenium-containing mineral material with carbon nutrients, nitrogen nutrients, and mineral nutrients; the slow-release selenium-containing mineral material being a suspension formed by dissolving selenium powder, gypsum, superphosphate, potassium dihydrogen phosphate, calcium sulfate, diatomaceous earth, nano-silica, and surfactant OP-10 in ethanol; the filtered and dried selenium-containing mineral core material; a monomer solution formed by mixing acrylic acid, butyl acrylate, and styrene; a packaging material obtained by adding the monomer solution, silane coupling agent, and azobisisobutyronitrile to isopropanol; the slow-release selenium-containing mineral core material; and finally, a polymer-encapsulated slow-release selenium-containing mineral material obtained by soaking in Bis-Tris buffer solution.

[0009] Because inorganic selenium is directly added to the cultivation substrate, elemental selenium is difficult to utilize effectively and it is difficult to form selenium-rich soil in black fungus. Furthermore, excessively high concentrations can inhibit the growth of black fungus mycelium and may cause selenium poisoning during the subsequent growth process. Selenium is most easily absorbed and utilized by black fungus in the form of selenite, but too low a concentration is also not conducive to absorption by black fungus, while too high a concentration can inhibit mycelial growth.

[0010] In this invention, selenium and mineral components are arranged in a slow-release structure, allowing for gradual release into the cultivation medium. Simultaneously, the released selenium reacts with the slow-released sodium chlorate at a suitable pH to produce selenite and chlorine dioxide. The selenite form is more easily absorbed by black fungus and effectively converted into organic selenium. Meanwhile, chlorine dioxide acts as a sterilizer during the growth of black fungus, thus ensuring its healthy growth. The slow release of selenium, with its initially low concentration and the selenium environment created by unreacted selenium, effectively promotes the growth of black fungus mycelium. As the concentration of selenite gradually increases, the selenite formed in the cultivation medium remains stable within a suitable concentration range for the growth of black fungus fruiting bodies, inhibiting excessive selenium concentration in the cultivation medium and preventing selenium poisoning in black fungus, while providing a stable and continuous effective concentration for rapid absorption by the black fungus.

[0011] The reaction formula between selenium and sodium chlorate is as follows:

[0012] 4ClO3 - +4H + +Se=4ClO2+H2O+H2SeO3

[0013] In this invention, sodium chlorate and minerals are released in a slow-release manner, which regulates the concentration changes of selenite and selenium in the cultivation medium, creating a special cultivation medium environment. In addition, it was found that the minerals and selenium are released in a slow-release manner simultaneously, which effectively promotes the absorption of selenium by black fungus, and also promotes the growth of black fungus mycelium and fruiting body.

[0014] Further, in the suspension 2, by weight, 1 part selenium powder, 18-20 parts gypsum, 4-5 parts superphosphate, 18-20 parts potassium dihydrogen phosphate, 8-10 parts calcium sulfate, 90 parts diatomaceous earth, 10 parts nano silica, 20 parts surfactant OP-10 and 130 parts ethanol are mixed and heated to 50-60°C, and stirred for 2-3 hours to obtain a nano silica-modified diatomaceous earth suspension.

[0015] Furthermore, the mass ratio of the slow-release selenium-containing mineral core material, packaging material, and water is 3:1:8~10. After being stirred evenly, the mixture is dried at 80~90℃ and then pulverized to obtain the slow-release selenium-containing mineral coarse material.

[0016] Furthermore, the slow-release sodium chlorate composite material is prepared by dissolving sodium chlorate in water to form a sodium chlorate solution, mixing diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol to prepare a suspension 1, adding the sodium chlorate solution to the suspension to obtain a mixture, vacuum filtering the mixture, drying the filtered solid to obtain a slow-release sodium chlorate core material, and then adding packaging material and water to form a slow-release sodium chlorate material.

[0017] Furthermore, by weight, the sodium chlorate solution contains 1 part sodium chlorate and 5 parts water, while suspension 1 contains 25-27 parts diatomaceous earth, 2 parts nano-activated carbon, 3 parts surfactant OP-10, and 195 parts ethanol.

[0018] Furthermore, diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol are mixed in a certain mass ratio, heated to 50~60℃, and stirred for 2~3 h to form a diatomaceous earth suspension modified with nano-activated carbon.

[0019] Furthermore, the mass ratio of the slow-release sodium chloride core material, packaging material, and water is 2:1:10, and the mixture is dried and pulverized at 80~90℃ to obtain the slow-release sodium chlorate material.

[0020] Furthermore, in the monomer solution, the mass ratio of acrylic acid, butyl acrylate and styrene is 1~1.2:2~2.5:1~1.2, and the mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50~55:40~45:2:1.

[0021] Furthermore, the cultivation material, by weight, contains 12-20 parts of carbon nutrients, 8-14 parts of nitrogen nutrients, 0.8-1.2 parts of slow-release sodium chlorate material, and 0.5-1 parts of slow-release selenium-containing mineral material.

[0022] Furthermore, the carbon nutrient components are composed of glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30.

[0023] Furthermore, the nitrogenous nutrient components are composed of rice bran, soybean meal, amino acids, urea, and rice husk in a ratio of 1:2:1:5:35.

[0024] Furthermore, the soaking treatment involves placing the crude, sustained-release selenium-containing mineral in Bis-Tris buffer solution, heating it to 35-40°C, soaking it for 4-5 hours, then filtering it, and finally drying it at 35-40°C to obtain the sustained-release selenium-containing mineral material.

[0025] A method for preparing a cultivation substrate for cultivating selenium-enriched black fungus, characterized by comprising the following steps:

[0026] Step 1: Preparation of sustained-release sodium chlorate composite material

[0027] (1) Dissolve sodium chlorate in water to make a solution, mix diatomaceous earth, nano activated carbon, surfactant OP-10 and ethanol to prepare suspension 1, add sodium chlorate solution to suspension to obtain mixed solution, vacuum filter the mixed solution, filter the solid and dry it to obtain slow-release sodium chlorate core material;

[0028] (2) Acrylic acid, butyl acrylate and styrene are mixed to form a monomer solution, and the monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol to form a packaging material;

[0029] (3) Add the slow-release sodium chlorate core material into the packaging material, then add water and stir evenly, dry and pulverize to obtain the slow-release sodium chlorate material;

[0030] Step 2: Preparation of slow-release selenium mineral materials

[0031] (1) Selenium powder, gypsum, superphosphate, potassium dihydrogen phosphate, calcium sulfate, diatomaceous earth, nano silica, surfactant OP-10 and ethanol are mixed to form suspension 2. Suspension 2 is vacuum filtered and the filtered solid is dried to obtain slow-release selenium-containing mineral core material.

[0032] (2) Mix acrylic acid, butyl acrylate and propylene to form a monomer solution, and add the monomer solution, silane coupling agent and azobisisobutyronitrile to isopropanol to obtain the packaging material;

[0033] (3) Add the slow-release selenium-containing mineral core material into the packaging material, then add water and stir, then dry and crush in sequence to obtain the slow-release selenium-containing mineral rough, and then use Bis-Tris buffer solution to soak and treat to make polymer-encapsulated slow-release selenium mineral material.

[0034] Step 3: Prepare the black fungus cultivation substrate

[0035] The black fungus cultivation substrate is prepared by mixing carbon nutrients, nitrogen nutrients, slow-release sodium chlorate material, slow-release selenium-containing mineral material, and water, and then bagged for later use.

[0036] Furthermore, in the packaging materials of steps one and two, the mass ratio of acrylic acid, butyl acrylate and styrene is 1~1.2:2~2.5:1~1.2.

[0037] Furthermore, the mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50~55:40~45:2:1.

[0038] Furthermore, by weight, the sodium chlorate solution in step one contains 1 part sodium chlorate and 5 parts water, while suspension 1 contains 25-27 parts diatomaceous earth, 2 parts nano-activated carbon, 3 parts surfactant OP-10, and 195 parts ethanol.

[0039] Furthermore, the diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol are mixed in a certain mass ratio, heated to 50~60℃, and stirred for 2~3 h to form a diatomaceous earth suspension modified with nano-activated carbon.

[0040] Furthermore, in step one, the mass ratio of the slow-release sodium chloride core material, packaging material, and water is 2:1:10, and the mixture is dried and pulverized at 80~90℃ to obtain the slow-release sodium chlorate material.

[0041] Further, in step two, suspension 2, by weight, 1 part selenium powder, 20 parts gypsum, 5 parts superphosphate, 20 parts potassium dihydrogen phosphate, 10 parts calcium sulfate, 90 parts diatomaceous earth, 10 parts nano silica, 20 parts surfactant OP-10 and 130 parts ethanol are mixed and heated to 50-60°C, and stirred for 2-3 hours to obtain a nano silica-modified diatomaceous earth suspension.

[0042] Furthermore, the mass ratio of the slow-release selenium-containing mineral core material, packaging material, and water is 3:1:8~10. After being stirred evenly, the mixture is dried at 80~90℃ and then pulverized to obtain the slow-release selenium-containing mineral coarse material.

[0043] Furthermore, the soaking treatment involves placing the crude, sustained-release selenium-containing mineral in Bis-Tris buffer solution, heating it to 35-40°C, soaking it for 4-5 hours, then filtering it, and finally drying it at 35-40°C to obtain the sustained-release selenium-containing mineral material.

[0044] By soaking the selenium in Bis-Tris buffer solution, the pH of the selenium slow-release environment was stabilized at 5.5-6.5. Under this environment, sodium chlorate and selenium react mainly to produce selenite. Selenite in selenite form is beneficial for the absorption and utilization of selenium during the growth of black fungus. In addition, this pH is also the optimal environment for the growth of black fungus, effectively promoting its growth.

[0045] Furthermore, the cultivation material, by weight, contains 12-20 parts of carbon nutrients, 8-14 parts of nitrogen nutrients, 0.8-1.2 parts of slow-release sodium chlorate material, 0.5-1 part of slow-release selenium-containing mineral material, and 30-40 parts of water.

[0046] Furthermore, the carbon nutrient components are composed of glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30.

[0047] Furthermore, the nitrogenous nutrient components are composed of rice bran, soybean meal, amino acids, urea, and rice husk in a ratio of 1:2:1:5:35.

[0048] Most specifically, a method for preparing a cultivation substrate for selenium-enriched black fungus is characterized by comprising the following steps:

[0049] Step 1: Preparation of sustained-release sodium chlorate composite material

[0050] (1) Prepare a sodium chlorate solution by mixing sodium chlorate and water at a mass ratio of 1:5. Mix diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol at a mass ratio of 25~27:3:6:195. Then heat to 50~60℃ and keep warm and stir for 2~3h to form suspension 1. Add sodium chlorate solution to suspension and stir to mix evenly to obtain a mixture. Vacuum filter the mixture and dry the filtered solid to obtain slow-release sodium chlorate core material.

[0051] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1~1.2:2~2.5:1~1.2 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 100~110℃. The reaction is continued for 1 h to form a packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50~55:40~45:2:1.

[0052] (3) Add the slow-release sodium chloride core material to the packaging material, then add water and stir evenly, dry, and pulverize to obtain the slow-release sodium chloride material. The mass ratio of the slow-release sodium chloride core material, packaging material and water is 2:1:10. Dry at 80~90℃.

[0053] Step 2: Preparation of slow-release selenium mineral materials

[0054] (1) According to the weight parts, 1 part of selenium powder, 20 parts of gypsum, 5 parts of superphosphate, 20 parts of potassium dihydrogen phosphate, 10 parts of calcium sulfate, 90 parts of diatomaceous earth, 10 parts of nano silica, 20 parts of surfactant OP-10 and 130 parts of ethanol are mixed and heated to 50~60℃, kept warm and stirred for 2~3 h to obtain suspension 2. Suspension 2 is vacuum filtered, and the filtered solid is dried to obtain slow-release selenium-containing mineral core material.

[0055] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1~1.2:2~2.5:1~1.2 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 100~110℃. The reaction is continued for 1 h to form a packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50~55:40~45:2:1.

[0056] (3) Mix the slow-release selenium-containing mineral core material, packaging material and water in a mass ratio of 3:1:8~10, stir evenly and dry at 80~90℃, then pulverize to obtain slow-release selenium-containing mineral crude, then place the slow-release selenium-containing mineral crude in Bis-Tris buffer solution, heat to 35~40℃, soak for 4~5 h, then filter, and dry at 35~40℃ to obtain slow-release selenium-containing mineral material;

[0057] Step 3: Prepare the black fungus cultivation substrate

[0058] The cultivation material, by weight, consists of 12-20 parts carbon nutrients, 8-14 parts nitrogen nutrients, 1-2 parts slow-release sodium chlorate material, 0.5-1 part slow-release selenium-containing mineral material, and 30-40 parts water. This mixture is then bagged and stored for later use. The carbon nutrients consist of glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30. The nitrogen nutrients consist of rice bran, soybean meal, amino acids, urea, and rice husks in a ratio of 1:2:1:5:35.

[0059] The present invention has the following technical effects:

[0060] In this invention, sodium chlorate and selenium are respectively formulated into specific slow-release systems. After slow release in the cultivation material, they react to generate selenite, which is easily absorbed and utilized by black fungus. This regulates the concentration of selenite in the cultivation material, promotes the growth of black fungus, increases the yield of black fungus, and significantly improves the quality of black fungus. The selenium content and amino acid content in black fungus are significantly increased. This cultivation material can be used for the seedling cultivation of black fungus strains with high selenium content, and high-quality strains of black fungus with high selenium content can be obtained through cultivation using this cultivation material. Detailed Implementation

[0061] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0062] Example 1

[0063] A cultivation method for increasing the selenium content of black fungus, comprising cultivating a substrate for selenium-enriched black fungus, is prepared according to the following steps:

[0064] Step 1: Preparation of sustained-release sodium chlorate composite material

[0065] (1) Prepare sodium chlorate solution by mixing sodium chlorate and water at a mass ratio of 1:5. Mix diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol at a mass ratio of 27:3:6:195. Then heat to 55°C and keep warm and stir for 2.5h to form suspension 1. Add sodium chlorate solution to suspension and stir to mix evenly to obtain a mixture. Vacuum filter the mixture and dry the filtered solid to obtain slow-release sodium chlorate core material.

[0066] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1.2:2:1 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 105℃. The reaction is continued for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 52:44:2:1.

[0067] (3) Add the slow-release sodium chloride core material to the packaging material, then add water and stir evenly, dry, and pulverize to obtain the slow-release sodium chloride material. The mass ratio of the slow-release sodium chloride core material, packaging material and water is 2:1:10. Dry at 80~90℃.

[0068] Step 2: Preparation of slow-release selenium mineral materials

[0069] (1) According to the weight parts, 1 part of selenium powder, 20 parts of gypsum, 5 parts of superphosphate, 20 parts of potassium dihydrogen phosphate, 10 parts of calcium sulfate, 90 parts of diatomaceous earth, 10 parts of nano silica, 20 parts of surfactant OP-10 and 130 parts of ethanol are mixed and heated to 55°C, and stirred for 2.5 h to obtain suspension 2. Suspension 2 is vacuum filtered, and the filtered solid is dried to obtain slow-release selenium-containing mineral core material.

[0070] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1.2:2:1 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 105℃. The reaction is continued for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 52:44:2:1.

[0071] (3) Mix the slow-release selenium-containing mineral core material, packaging material and water in a mass ratio of 3:1:9, stir evenly and dry at 85°C, then pulverize to obtain slow-release selenium-containing mineral crude material, then place the slow-release selenium-containing mineral crude material in Bis-Tris buffer solution, heat to 40°C, soak for 4.5 h, then filter, and dry at 40°C to obtain slow-release selenium-containing mineral material;

[0072] Step 3: Prepare the black fungus cultivation substrate

[0073] The cultivation material, by weight, consists of 15 parts carbon nutrients, 10 parts nitrogen nutrients, 1 part slow-release sodium chlorate material, 0.8 parts slow-release selenium-containing mineral material, and 35 parts water, mixed together and bagged for later use. The carbon nutrients are glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30, and the nitrogen nutrients are rice bran, soybean meal, amino acids, urea, and rice husks in a ratio of 1:2:1:5:35.

[0074] Comparative Example 1

[0075] Compared with Example 1, no slow-release sodium chlorate material was prepared, i.e., step one was omitted, and the rest of the cultivation substrate formulation was the same as in Example 1.

[0076] Comparative Example 2

[0077] Compared to Example 1, the sodium chlorate component was not subjected to a slow-release treatment; instead, an equivalent amount of sodium chlorate as in Example 1 was directly added to the cultivation substrate.

[0078] Comparative Example 3

[0079] Compared with Example 1, in step two, the preparation of the slow-release selenium-containing mineral material did not involve a subsequent soaking treatment, and the remaining steps were the same as in Example 1.

[0080] Comparative Example 4

[0081] Compared with Example 1, the suspension in the preparation of the slow-release selenium core material does not contain gypsum, superphosphate, potassium dihydrogen phosphate and calcium sulfate. All of the above components are added directly when mixing and preparing the cultivation material, and the remaining steps are the same as in Example 1.

[0082] The culture media prepared in Example 1 and each comparative example were bagged at 2.5 kg / bag, sterilized, and inoculated with the same black fungus strain. They were then cultivated and managed under the same conditions. During the cultivation process, starting from the inoculation, the concentration of selenite in the cultivation bags was measured every 15 days. The results are shown in Table 1.

[0083] Table 1: Changes in selenite concentration in cultivation substrate during cultivation management

[0084]

[0085] As can be seen, in this invention, the selenite content in the cultivation medium gradually increases with the increase of detection time. In the early stage, due to the slow release of selenium and sodium chlorate, the concentrations of selenium and selenite are both low, which is within the concentration range conducive to the growth of black fungus mycelium, thus promoting mycelial growth. After 60 days, a relatively stable concentration range is formed, which is conducive to the growth of black fungus fruiting bodies and the effective absorption of selenite. In Comparative Example 1, because sodium chlorate was not added, the slowly released selenium was difficult to be converted into a large amount of selenite in the cultivation medium, which promotes mycelial growth and is more easily absorbed and utilized by black fungus. Instead, it mainly accumulated in the cultivation medium in the form of selenium, which significantly inhibited mycelial formation. The unfavorable growth of mycelium also affected the subsequent growth of fruiting bodies. In Comparative Example 2, because sodium chlorate was not released gradually, the initially released selenium reacted directly and completely with the sufficient amount of sodium chlorate, generating a large amount of selenite. This caused the selenite to accumulate rapidly initially, exceeding the mycelial growth requirements and the optimal concentration limit, thus inhibiting mycelial growth and the absorption and utilization of selenite by black fungus during its growth. In Comparative Example 3, due to unsuitable pH, the reaction between sodium chlorate and selenium was relatively slow, resulting in a low concentration of selenite. As selenium was released gradually, elemental selenium and sodium chlorate slowly accumulated in the cultivation bag, and the selenite concentration still did not meet the requirements. In Comparative Example 4, because the mineral components were not released synchronously with selenium, a difference in the mineral environment of the cultivation medium occurred. Although a suitable concentration of selenite was generated, the absorption of selenite by black fungus was not ideal, and selenite gradually accumulated in the cultivation medium.

[0086] During cultivation, a control group was inoculated with a culture medium that did not contain slow-release selenium mineral materials or slow-release sodium chlorate materials, and the minerals were directly added. The mycelial growth, yield, selenium content and other relevant indicators of black fungus are shown in Table 2.

[0087] Table 2:

[0088]

[0089] Note: The number of "+" signs for mycelial growth indicates the strength of the shape.

[0090] Although my country's national standards currently do not impose unlimited limits on the selenium content in edible fungi, some provincial local standards do impose limits. For example, DB36 / T566-2009, "Jiangxi Provincial Local Standard Review Food Selenium Content Classification Standard," stipulates that the selenium content in edible fungi should not exceed 1.0 mg / kg. Therefore, this standard is used as the safety standard. The selenium content of dried black fungus in this invention is 0.47 mg / kg, which is within the safety standard range, and the yield is significantly increased by 11.70% compared to the control group. In contrast, the selenium content in Comparative Example 2 is 1.29 mg / kg, and the organic selenium content is only 92.4%. Both the selenium content and the organic selenium content pose certain risks to human health. Although the yield of black fungus in Comparative Example 4 is significantly higher than that of the control group, the increase in selenium content is not significant, and the organic selenium content is also low. In Comparative Examples 1 and 3, mycelial growth was inhibited due to selenium accumulation, resulting in a decrease in the yield of black fungus. Furthermore, the low concentration of easily absorbed selenite in the cultivation substrate led to an unsatisfactory selenium content in the black fungus. In addition, it can be seen that the total amino acid content in the black fungus cultivated in Example 1 was significantly increased, with the proportion of essential amino acids reaching 45.28%, compared to only 42.87% in the control group. In Comparative Examples 1-3, the proportion of essential amino acids in the black fungus was significantly lower than that in the control group.

[0091] Example 2

[0092] A method for preparing a cultivation substrate for cultivating selenium-enriched black fungus includes the following steps:

[0093] Step 1: Preparation of sustained-release sodium chlorate composite material

[0094] (1) Sodium chlorate and water are prepared into sodium chlorate solution at a mass ratio of 1:5. Diatomaceous earth, nano activated carbon, surfactant OP-10 and ethanol are mixed at a mass ratio of 26:3:6:195. The mixture is then heated to 50°C and stirred for 3 hours to form suspension 1. Sodium chlorate solution is added to suspension and stirred until homogeneous to obtain a mixture. The mixture is vacuum filtered and the filtered solid is dried to obtain slow-release sodium chlorate core material.

[0095] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1:2.5:1.2 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 100℃. The reaction is continued for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 55:45:2:1.

[0096] (3) Add the slow-release sodium chloride core material to the packaging material, then add water and stir evenly, dry, and pulverize to obtain the slow-release sodium chloride material. The mass ratio of the slow-release sodium chloride core material, packaging material and water is 2:1:10. Dry at 80℃.

[0097] Step 2: Preparation of slow-release selenium mineral materials

[0098] (1) According to the weight parts, 1 part of selenium powder, 20 parts of gypsum, 5 parts of superphosphate, 20 parts of potassium dihydrogen phosphate, 10 parts of calcium sulfate, 90 parts of diatomaceous earth, 10 parts of nano silica, 20 parts of surfactant OP-10 and 130 parts of ethanol are mixed and heated to 50°C, and stirred for 3 h to obtain suspension 2. Suspension 2 is vacuum filtered, and the filtered solid is dried to obtain slow-release selenium-containing mineral core material.

[0099] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1:2.5:1.2 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 100℃. The reaction is continued for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 55:45:2:1.

[0100] (3) Mix the slow-release selenium-containing mineral core material, packaging material and water in a mass ratio of 3:1:8, stir evenly and dry at 90°C, then pulverize to obtain slow-release selenium-containing mineral crude material, then place the slow-release selenium-containing mineral crude material in Bis-Tris buffer solution, heat to 35°C, soak for 5 h, then filter, and dry at 35°C to obtain slow-release selenium-containing mineral material;

[0101] Step 3: Prepare the black fungus cultivation substrate

[0102] The cultivation material, by weight, consists of 12 parts carbon nutrients, 8 parts nitrogen nutrients, 2 parts slow-release sodium chlorate material, 1 part slow-release selenium-containing mineral material, and 35 parts water, mixed together and bagged for later use. The carbon nutrients are glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30, and the nitrogen nutrients are rice bran, soybean meal, amino acids, urea, and rice husks in a ratio of 1:2:1:5:35.

[0103] Compared with conventional cultivation materials (with the addition of slow-release selenium mineral materials and slow-release sodium chlorate materials, and the mineral components being directly added to the cultivation materials), the black fungus cultivated in this embodiment has a 12.14% higher yield, a selenium content of 0.42 mg / kg of dried fungus, and an amino acid content of 126.49 mg / g, of which the proportion of essential amino acids for the human body reaches 44.17%.

[0104] Example 3

[0105] A method for preparing a cultivation substrate for cultivating selenium-enriched black fungus includes the following steps:

[0106] Step 1: Preparation of sustained-release sodium chlorate composite material

[0107] (1) Sodium chlorate and water are prepared into sodium chlorate solution at a mass ratio of 1:5. Diatomaceous earth, nano activated carbon, surfactant OP-10 and ethanol are mixed at a mass ratio of 25:3:6:195. Then the mixture is heated to 60°C and stirred for 2 hours to form suspension 1. Sodium chlorate solution is added to suspension and stirred to mix evenly to obtain a mixture. The mixture is vacuum filtered and the filtered solid is dried to obtain slow-release sodium chlorate core material.

[0108] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1.1:2.2:1.1 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 110°C. The reaction is continued at the temperature for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50:40:2:1.

[0109] (3) Add the slow-release sodium chloride core material to the packaging material, then add water and stir evenly, dry, and pulverize to obtain the slow-release sodium chloride material. The mass ratio of the slow-release sodium chloride core material, packaging material and water is 2:1:10. Dry at 80~90℃.

[0110] Step 2: Preparation of slow-release selenium mineral materials

[0111] (1) According to the weight parts, 1 part of selenium powder, 20 parts of gypsum, 5 parts of superphosphate, 20 parts of potassium dihydrogen phosphate, 10 parts of calcium sulfate, 90 parts of diatomaceous earth, 10 parts of nano silica, 20 parts of surfactant OP-10 and 130 parts of ethanol are mixed and heated to 60°C, and stirred for 2 hours to obtain suspension 2. Suspension 2 is vacuum filtered, and the filtered solid is dried to obtain slow-release selenium-containing mineral core material.

[0112] (2) Acrylic acid, butyl acrylate and styrene are mixed in a mass ratio of 1.1:2.2:1.1 to form a monomer solution. The monomer solution, silane coupling agent and azobisisobutyronitrile are added to isopropanol at a temperature of 110°C. The reaction is continued at the temperature for 1 h to form packaging material. The mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50:40:2:1.

[0113] (3) Mix the slow-release selenium-containing mineral core material, packaging material and water in a mass ratio of 3:1:10, stir evenly and dry at 85°C, then pulverize to obtain slow-release selenium-containing mineral crude material, then place the slow-release selenium-containing mineral crude material in Bis-Tris buffer solution, heat to 38°C and soak for 4 hours, then filter, and dry at 38°C to obtain slow-release selenium-containing mineral material;

[0114] Step 3: Prepare the black fungus cultivation substrate

[0115] The cultivation material, by weight, consists of 20 parts carbon nutrients, 14 parts nitrogen nutrients, 2 parts slow-release sodium chlorate material, 0.5 parts slow-release selenium-containing mineral material, and 40 parts water, mixed together and bagged for later use. The carbon nutrients are glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:30, and the nitrogen nutrients are rice bran, soybean meal, amino acids, urea, and rice husks in a ratio of 1:2:1:5:35.

[0116] Compared with conventional cultivation materials (with the addition of slow-release selenium mineral materials and slow-release sodium chlorate materials, and the mineral components being directly added to the cultivation materials), the black fungus cultivated in this embodiment has a 10.57% higher yield, a selenium content of 0.43 mg / kg of dried fungus, and an amino acid content of 124.52 mg / g, of which the proportion of essential amino acids for the human body reaches 43.95%.

Claims

1. A cultivation method for increasing the selenium content of black fungus, comprising a cultivation substrate for increasing the selenium content of black fungus, characterized in that: The cultivation medium is prepared by mixing slow-release sodium chlorate composite material and slow-release selenium-containing mineral material with carbon nutrients, nitrogen nutrients, and mineral nutrients. The slow-release selenium-containing mineral material is prepared by dissolving selenium powder, gypsum, superphosphate, potassium dihydrogen phosphate, calcium sulfate, diatomaceous earth, nano-silica, and surfactant OP-10 in ethanol to form a suspension 2, which is then filtered and dried to obtain the slow-release selenium-containing mineral core material. Acrylic acid, butyl acrylate, and styrene are mixed to form a monomer solution, and polymers are added to isopropanol. A packaging material is prepared by mixing a monomer solution, a silane coupling agent, and azobisisobutyronitrile (AIBN). Then, a sustained-release selenium-containing mineral core material is added to obtain a sustained-release selenium-containing mineral aggregate. This aggregate is then treated with Bis-Tris buffer solution to prepare a polymer-encapsulated sustained-release selenium-containing mineral material. The suspension 2 contains, by weight, 1 part selenium powder, 18-20 parts gypsum, 4-5 parts superphosphate, 18-20 parts potassium dihydrogen phosphate, 8-10 parts calcium sulfate, 90 parts diatomaceous earth, 10 parts nano-silica, 20 parts surfactant OP-10, and 130 parts ethanol. The mixture is then heated to 50-60°C and stirred for 2-3 minutes. The slow-release sodium chlorate composite material is prepared by dissolving sodium chlorate in water to form a sodium chlorate solution, mixing diatomaceous earth, nano-activated carbon, surfactant OP-10, and ethanol to prepare suspension 1, adding the sodium chlorate solution to suspension 1 to obtain a mixture, vacuum filtering the mixture, drying the filtered solid to obtain the slow-release sodium chlorate core material, and then adding packaging material and water to prepare the slow-release sodium chlorate material. The sodium chlorate solution contains 1 part sodium chlorate and 5 parts water. Suspension 1 contains 25-27 parts diatomaceous earth, 2 parts nano-activated carbon, 3 parts surfactant OP-10, and 195 parts ethanol. The cultivation material, by weight, contains 12-20 parts carbon nutrients, 8-14 parts nitrogen nutrients, 0.8-1.2 parts slow-release sodium chlorate material, and 0.5-1 parts slow-release selenium-containing mineral material.

2. The cultivation method for increasing the selenium content of black fungus as described in claim 1, characterized in that: The mass ratio of the slow-release selenium-containing mineral core material, packaging material and water is 3:1:8~10. After being stirred evenly, the mixture is dried at 80~90℃ and then pulverized to obtain the crude slow-release selenium-containing mineral.

3. A cultivation method for increasing the selenium content of black fungus as described in claim 1 or 2, characterized in that: Diatomaceous earth, nano-activated carbon, surfactant OP-10 and ethanol are mixed in a certain mass ratio, heated to 50~60℃, and stirred for 2~3 h to form a diatomaceous earth suspension modified with nano-activated carbon.

4. The cultivation method for increasing the selenium content of black fungus as described in claim 3, characterized in that: In the monomer solution, the mass ratio of acrylic acid, butyl acrylate and styrene is 1~1.2:2~2.5:1~1.2, and the mass ratio of isopropanol, monomer solution, silane coupling agent and azobisisobutyronitrile is 50~55:40~45:2:

1.

5. The cultivation method for increasing the selenium content of black fungus as described in claim 4, characterized in that: The carbon nutrient is composed of glucose, fructose, sucrose, starch, and sawdust in a mass ratio of 2:1:2:3:

30.

6. A cultivation method for increasing the selenium content of black fungus as described in claim 4 or 5, characterized in that: The nitrogenous nutrient composition is composed of rice bran, soybean meal, amino acids, urea, and rice husk in a ratio of 1:2:1:5:35.

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