Cultivation method of selenium-rich edible mushrooms

Abstract

The invention discloses a cultivation method of selenium-rich edible mushrooms. The cultivation method comprises the following steps: S1, manufacturing a culture medium mushroom bag; wherein the culture medium fungus bag comprises selenium-rich crops, wood chips, cottonseed hulls, soybean meal and biochar; the selenium-rich crops comprise selenium-rich wheat and / or selenium-rich rice; s2, sterilizing the culture medium fungus bag; s3, in a sterile environment, edible fungus strains are inoculated to the two ends and the center of the sterilized culture medium fungus bag; and S4, stacking the inoculated culture medium fungus bags in a greenhouse, carrying out proper ventilation and spraying water supply on the greenhouse, controlling the temperature and humidity in the greenhouse, and carrying out fermentation cultivation for 60-90 days to obtain the selenium-rich edible fungi. The edible mushrooms can absorb organic selenium in selenium-rich crops in the cultivation process, and the edible mushrooms with high organic selenium content are obtained.

Description

Technical Field

[0001] The invention relates to the technical field of edible fungus cultivation, and in particular to a method for cultivating selenium-enriched edible fungi. Background Art

[0002] Edible fungi are the sixth largest category of products in the planting industry after grain, cotton, oil, fruit and vegetables. They are nutritious and delicious. Selenium-rich edible fungi can be used as a highly effective selenium supplement, providing a safe and effective source of selenium for people who are deficient in selenium.

[0003] When cultivating selenium-rich edible fungi, the prior art is to increase the selenium content in the edible fungi by spraying selenium fertilizer on the surface of the edible fungi so that the edible fungi absorb the selenium in the selenium fertilizer. However, since the selenium fertilizer includes a large amount of inorganic selenium, after spraying the selenium fertilizer, the edible fungi cannot convert all the inorganic selenium into organic selenium during the growth cycle of the edible fungi. In this way, there will still be a large amount of inorganic selenium in the edible fungi after they mature. These edible fungi with a large amount of inorganic selenium are prone to selenium poisoning when eaten by humans.

[0004] Therefore, there is an urgent need to provide a method for cultivating selenium-rich edible fungi to avoid the presence of a large amount of inorganic selenium in mature edible fungi. Summary of the invention

[0005] The purpose of the present invention is to provide a method for cultivating selenium-enriched edible fungi to solve the problem of low organic selenium content in the edible fungi cultivation process proposed in the above background technology, thereby improving the nutritional value of the edible fungi and food safety.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for cultivating selenium-enriched edible fungi comprises the following steps: S1. preparing culture medium bags; wherein the culture medium bags comprise selenium-enriched crops, wood chips, cottonseed hulls, soybean meal and biochar; the selenium-enriched crops comprise selenium-enriched wheat and / or selenium-enriched rice; S2. sterilizing the culture medium bags; S3. inoculating edible fungi strains at both ends and the center of the sterilized culture medium bags under a sterile environment; S4. stacking the inoculated culture medium bags in a greenhouse, ventilating the greenhouse appropriately and spraying water to supply the greenhouse, controlling the temperature and humidity in the greenhouse, and fermenting and cultivating for 60 to 90 days to obtain selenium-enriched edible fungi.

[0008] As a preferred technical solution of the present invention, the preparation of the culture medium bag includes: weighing 20 to 22 parts by weight of selenium-enriched wheat, 16 to 20 parts by weight of selenium-enriched rice, 10 to 13 parts by weight of sawdust, 7 to 10 parts by weight of cottonseed hulls, 6 to 8 parts by weight of soybean meal, and 5 to 8 parts by weight of biochar, and mixing them; putting the mixed selenium-enriched wheat, selenium-enriched rice, sawdust, cottonseed hulls, soybean meal and biochar into a cylindrical breathable gauze bag to obtain a cylindrical culture medium bag.

[0009] As a preferred technical solution of the present invention, before weighing the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk, the method also includes: crushing the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk so that the particle sizes of the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk are all greater than or equal to 0.8 mm and less than or equal to 1.2 mm.

[0010] As a preferred technical solution of the present invention, the preparation of biochar includes: weighing 28 to 32 parts by weight of nut shells, 20 to 25 parts by weight of sawdust and 18 to 20 parts by weight of rice husks, and mixing them; placing the mixed nut shells, sawdust and rice husks in a carbonization furnace, and filling the carbonization furnace with nitrogen, heating at a rate of 5°C / min until the temperature in the carbonization furnace is between 520°C and 540°C; carbonizing the nut shells, sawdust and rice husks in the carbonization furnace for 2h to 2.5h to obtain biochar.

[0011] As a preferred technical solution of the present invention, the mass ratio of peanut shell, walnut shell and almond shell in the nut shell is 2:2:1.

[0012] As a preferred technical solution of the present invention, before weighing the nut shells and sawdust, the method further includes: crushing the nut shells and sawdust to make the particle sizes of the nut shells and sawdust greater than or equal to 1.5 mm and less than or equal to 2.0 mm.

[0013] As a preferred technical solution of the present invention, sterilizing the culture medium bag includes: placing the cylindrical culture medium bag in a normal pressure sterilizer and adding purified water; heating the purified water until the water boils and continuing heating for 7h to 8h; closing the normal pressure sterilizer and maintaining for 8 to 10h until the temperature in the cylindrical culture medium bag drops below 25°C.

[0014] As a preferred technical solution of the present invention, before inoculating the edible fungus strains at both ends and the center of the sterilized culture medium bag, it also includes: selecting vigorous, strong, and uncontaminated edible fungus strains of the appropriate season.

[0015] As a preferred technical solution of the present invention, in S4: the temperature T in the greenhouse satisfies: 15°C≤T≤25°C; the humidity %RH in the greenhouse satisfies: 85%≤%RH≤95%.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the present invention, selenium-enriched wheat and / or selenium-enriched rice are added to the culture medium bacteria bag, so that the organic selenium in the selenium-enriched wheat and / or selenium-enriched rice can be transferred to the edible fungi to obtain selenium-enriched edible fungi with high organic selenium content.

[0018] 2. The present invention treats nut shells, sawdust, and rice husks by high-temperature carbonization in a carbonization furnace. Under high-temperature anaerobic conditions, lignin, cellulose, and some organic substances in nut shells, sawdust, and rice husks undergo thermal decomposition reactions, releasing gas and liquid to form a carbon-rich microporous structure. Carbonization under high-temperature conditions forms more pores in biochar while generating oxygen-containing functional groups such as carboxyl and hydroxyl groups, increasing the chemical activity and adsorption capacity of biochar. The porous structure of biochar can absorb and retain a large amount of water, improve the water retention rate of the culture medium, reduce the evaporation and loss of water, and promote the absorption and utilization of nutrients in the strains. At the same time, biochar can provide a C source for the culture medium, accelerate the growth of mycelium, and improve the nutritional value of edible fungi. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flow chart of cultivating selenium-enriched edible fungi. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0023] Selenium can be divided into inorganic selenium and organic selenium. Inorganic selenium and organic selenium are two different forms of selenium. Inorganic selenium refers to elemental Se or Se. 2- Inorganic ion forms include selenite (such as Na2SeO3), selenious acid (such as H2SeO3), selenate (such as Na2SeO4), etc. Organic selenium refers to compounds containing carbon-selenium bonds, including methyl selenium, methylene selenium, thiomethyl selenium, etc.

[0024] Inorganic selenium can be reduced to some intermediates containing -Se-H bonds in the human body, but this reduction process requires the action of some reductases, and its absorption and utilization rate is generally only about 10%, and the intermediates obtained by reduction are easily oxidized to inorganic selenium forms, thereby reducing the biological effect. Inorganic selenium is relatively toxic. Excessive intake can cause acute poisoning such as nausea, vomiting, and diarrhea. Long-term intake can also cause chronic poisoning such as liver damage and anemia.

[0025] Organic selenium can be converted into some intermediates containing -Se-C bonds through metabolic processes in the human body. These intermediates can directly participate in biological processes such as protein synthesis and DNA repair. In addition, organic selenium can also be converted into methyl selenium through methylation reactions, further improving its biological effects. Its absorption and utilization rate in the human body can reach more than 50%. Organic selenium has low toxicity. Large intake can cause mild symptoms such as gastrointestinal discomfort and dizziness, but will not cause acute or chronic poisoning. Intake of organic selenium within an appropriate range can improve immunity and prevent cancer.

[0026] Selenium-enriched edible fungi refer to edible fungi grown in an environment rich in selenium. They not only inherit the nutritional value of traditional edible fungi, but also have higher health value due to their rich selenium content. Selenium-enriched edible fungi are designed to provide organic selenium to the human body to enhance its effects in anti-oxidation, immunity, and prevention of cardiovascular diseases and cancer.

[0027] However, the existing method of cultivating selenium-enriched edible fungi by spraying selenium fertilizer usually contains more inorganic selenium, which can easily lead to selenium poisoning after human consumption. Therefore, after in-depth research, the inventor provides a method for cultivating selenium-enriched edible fungi to increase the content of organic selenium in selenium-enriched edible fungi and reduce the content of inorganic selenium in selenium-enriched edible fungi.

[0028] See also Figure 1 A method for cultivating selenium-rich edible fungi provided in an embodiment of the present application comprises the following steps: S1. preparing a culture medium bag; wherein the culture medium bag comprises selenium-rich crops, sawdust, cottonseed hulls, bean curd and biochar; the selenium-rich crops comprise selenium-rich wheat and / or selenium-rich rice; S2. sterilizing the culture medium bag; S3. inoculating edible fungi strains at both ends and the center of the sterilized culture medium bag in a sterile environment; S4. stacking the inoculated culture medium bags in a greenhouse, ventilating and spraying the greenhouse with water appropriately, controlling the temperature and humidity in the greenhouse, and fermenting and cultivating for 60 to 90 days to obtain selenium-rich edible fungi.

[0029] In this embodiment, selenium-enriched wheat and / or selenium-enriched rice are added to the culture medium bacteria bag to obtain selenium-enriched edible fungi with high organic selenium content. This is because, during the edible fungi cultivation process, the selenium-enriched wheat and / or selenium-enriched rice in the culture medium bacteria bag can provide organic selenium to the edible fungi, such as selenomethionine, selenomethylselenocysteine ​​and other organic forms of selenium, which have high biological activity and nutritional value and are easier to be absorbed and utilized by the human body.

[0030] In addition, the present invention also adds biochar to the culture medium bag. The porous structure of the biochar can absorb and retain a large amount of water, improve the water retention rate of the culture medium, reduce the evaporation and loss of water, and promote the absorption and utilization of nutrients in the bacteria. At the same time, the biochar can provide a carbon source for the culture medium, thereby accelerating the growth of mycelium and increasing the nutritional value of edible fungi.

[0031] After the cylindrical culture medium bags are stacked, the contact area between adjacent culture medium bags is smaller than that of the prismatic ones, which is beneficial to increase the air permeability of the culture medium bags, facilitates the outside air to enter the culture medium bags, and provides a good ventilation environment for edible fungi.

[0032] In some embodiments, before weighing the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk, the method also includes: crushing the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk so that the particle sizes of the selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk are greater than or equal to 0.8 mm and less than or equal to 1.2 mm.

[0033] When the particle size of selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk is less than 0.8 mm, selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk may leak out of the culture medium bag, resulting in a decrease in the content of selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk. On the contrary, when the particle size of selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk is greater than 1.2 mm, the selenium in selenium-enriched wheat and selenium-enriched rice is not easily transferred to the edible fungi, and the nutrients in sawdust and cottonseed husk are not easily absorbed and utilized by the edible fungi.

[0034] Based on this, this embodiment makes the particle size of selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk greater than or equal to 0.8 mm and less than or equal to 1.2 mm, so that selenium-rich wheat, selenium-rich rice, sawdust and cottonseed husk are not easy to leak out of the culture medium bag, and the selenium in the selenium wheat and selenium-rich rice can be more easily transferred to the edible fungi, and the nutrients in the sawdust and cottonseed husk are more easily absorbed and utilized by the edible fungi.

[0035] In some embodiments, the preparation of biochar includes: weighing 28 to 32 parts by weight of nut shells, 20 to 25 parts by weight of sawdust and 18 to 20 parts by weight of rice husks, and mixing them; placing the slowly mixed nut shells, sawdust and rice husks in a carbonization furnace, and filling the carbonization furnace with nitrogen, heating at a rate of 5°C / min until the temperature in the carbonization furnace is between 520°C and 540°C; carbonizing the nut shells, sawdust and rice husks in the carbonization furnace for 2h to 2.5h to obtain biochar.

[0036] In this embodiment, nut shells, sawdust, and rice husks are carbonized at high temperature in a carbonization furnace. Under high temperature and anaerobic conditions, lignin, cellulose, and some organic matter in the nut shells, sawdust, and rice husks undergo thermal decomposition reactions to release gases and liquids, forming a carbon-rich microporous structure in the material. Carbonization under high temperature conditions causes the biochar to form more pores while producing oxygen-containing functional groups such as carboxyl and hydroxyl groups, thereby increasing the chemical activity and adsorption capacity of the biochar. The porous structure of the biochar can absorb and retain a large amount of water, improve the water retention rate of the culture medium, reduce water evaporation and loss, and promote the absorption and utilization of nutrients in the fungus. At the same time, the biochar can provide a C source for the culture medium, thereby accelerating the growth of mycelium, improving the conversion efficiency of inorganic selenium to organic selenium, and increasing the nutritional value of edible fungi.

[0037] In some embodiments, the mass ratio of peanut shell, walnut shell and almond shell in the nut shell is 2:2:1.

[0038] In this embodiment, since peanut shells, walnut shells and almond shells naturally have large empty holes, during the high-temperature carbonization process of peanut shells, walnut shells and almond shells, more carbon-rich microporous structures can also be formed, increasing the chemical activity and adsorption capacity of biochar. The porous structure of biochar can absorb and retain a large amount of water.

[0039] In some embodiments, before weighing the nut shells and wood chips, the process further includes: crushing the nut shells and wood chips so that the particle size of the nut shells is greater than or equal to 1.5 mm and less than or equal to 2.0 mm.

[0040] In this embodiment, nut shells and sawdust are crushed to a particle size greater than or equal to 1.5 mm and less than or equal to 2.0 mm, so that the crushed nut shells and sawdust are not easy to leak out of the culture medium bag, and more carbon-rich microporous structures can be formed, increasing the chemical activity and adsorption capacity of biochar to absorb and retain a large amount of water.

[0041] In some embodiments, sterilizing the culture medium bag includes: placing the cylindrical culture medium bag in a normal pressure sterilizer and adding purified water; heating the purified water until it boils and continuing heating for 7 to 8 hours; closing the normal pressure sterilizer and maintaining the temperature for 8 to 10 hours until the temperature inside the cylindrical culture medium bag drops below 25°C.

[0042] In this embodiment, the edible fungi strains are sterilized in the above steps by a normal pressure autoclave, which can reduce the foreign bacteria carried by the edible fungi strains and prevent the edible fungi strains from being affected by more foreign bacteria during the growth process in the culture medium bag and being unable to absorb more organic selenium and inorganic selenium, which is beneficial to further increase the selenium enrichment of the edible fungi.

[0043] In some embodiments, before inoculating the edible fungi strains at both ends and the center of the sterilized culture medium bag, it also includes selecting edible fungi strains of appropriate season that are vigorous, strong, and free of contamination by other bacteria.

[0044] In this embodiment, the selection of vigorous, robust, and timely edible fungi strains without foreign bacterial contamination is conducive to the expected growth of the edible fungi strains in the culture medium bag, thereby obtaining high-quality edible fungi.

[0045] In some embodiments, in the aforementioned S4: the temperature T in the greenhouse satisfies: 15°C ≤ T ≤ 25°C; the humidity %RH in the greenhouse satisfies: 85% ≤ %RH ≤ 95%.

[0046] In this embodiment, providing the above temperature in the large basin can meet the growth conditions of conventional edible fungi, so as to provide excellent cultivation conditions for the edible fungi and enable the edible fungi to grow with high quality.

[0047] Based on the above embodiments, the inventors also conducted the following experiments:

[0048] It should be noted that the raw materials used in the following experiments are all commercially available raw materials. Among them, the edible fungi can be Ganoderma lucidum, shiitake mushrooms, straw mushrooms, mushrooms, black fungus, white fungus, hericium, bamboo fungus, matsutake, trichoderma, red mushroom, cordyceps, truffles, white mushrooms, boletus, morels, saddle mushrooms and truffles. The strain used in this experiment is Ganoderma lucidum.

[0049] Experiment 1:

[0050] A method for cultivating selenium-enriched edible fungi comprises the following cultivation steps:

[0051] S1. Preparation of culture medium bacteria bag; Processing of selenium-rich crops: Use a grinder to grind selenium-rich wheat and selenium-rich rice respectively until the particle size of selenium-rich wheat and selenium-rich rice is 1.2mm. Preparation of biochar: Peanut shells, walnut shells and almond shells are composed of nut shells in a mass ratio of 2:2:1; Use a grinder to grind nut shells and sawdust to meet the particle size of 1.5-2.0mm; Weigh 28 parts of nut shells, 20 parts of sawdust, and 18 parts of rice husks, mix them, and place them in a carbonization furnace. In an inert gas nitrogen atmosphere, heat up to 520℃ at a heating rate of 5℃ / min and carbonize for 2.5h to obtain biochar. Weigh 20 parts by weight of selenium-enriched wheat, 16 parts by weight of selenium-enriched rice, 10 parts by weight of sawdust, 7 parts by weight of cottonseed husks, 6 parts by weight of soybean meal, and 5 parts by weight of biochar, and mix them; put the mixed selenium-enriched wheat, selenium-enriched rice, sawdust, cottonseed husks, soybean meal, and biochar into a cylindrical breathable gauze bag to obtain a cylindrical culture medium bag.

[0052] S2. Sterilize the culture medium bag; place the cylindrical culture medium bag in a normal pressure sterilizer and add purified water; heat the purified water until it boils and continue heating for 7 hours; close the normal pressure sterilizer and keep it for 8 hours until the temperature inside the cylindrical culture medium bag drops below 25°C.

[0053] S3. In a sterile environment, inoculate the edible fungi strains at both ends and the center of the sterilized culture medium bag; select vigorous, robust, and suitable edible fungi strains without contamination by other bacteria. In a sterile or nearly sterile room, use an inoculation hoe to inoculate the strains at both ends and the center of the culture medium bag, with the inoculation amount being 6% of the culture medium mass.

[0054] S4. The inoculated culture medium bags are stacked in a greenhouse and fermented and cultivated for 90 days to obtain selenium-rich Ganoderma lucidum. During the cultivation process, spraying water is used in the greenhouse, and proper ventilation is maintained to keep the temperature in the greenhouse at 15°C to 25°C and the humidity at 85 to 95%.

[0055] Experiment 2:

[0056] A method for cultivating selenium-enriched edible fungi comprises the following cultivation steps:

[0057] S1. Preparation of culture medium bacteria bag; Processing of selenium-rich crops: Use a grinder to grind selenium-rich wheat and selenium-rich rice respectively until the particle size of selenium-rich wheat and selenium-rich rice is 1.2mm. Preparation of biochar: Peanut shells, walnut shells and almond shells are composed of nut shells in a mass ratio of 2:2:1; Use a grinder to grind nut shells and sawdust to a particle size of 2.0mm; Weigh 32 parts of nut shells, 25 parts of sawdust, and 20 parts of rice husks, mix them, and place them in a carbonization furnace. In an inert gas nitrogen atmosphere, heat the temperature to 540℃ at a heating rate of 5℃ / min and carbonize for 2h to obtain biochar. Weigh 22 parts by weight of selenium-enriched rice, 20 parts by weight of selenium-enriched wheat, 13 parts by weight of sawdust, 10 parts by weight of cottonseed husks, 8 parts by weight of soybean meal, and 8 parts by weight of biochar, and mix them; put the mixed selenium-enriched wheat, selenium-enriched rice, sawdust, cottonseed husks, soybean meal, and biochar into a cylindrical breathable gauze bag to obtain a cylindrical culture medium bag.

[0058] S2. Sterilize the culture medium bag; place the cylindrical culture medium bag in a normal pressure sterilizer and add purified water; heat the purified water until it boils and continue heating for 8 hours; close the normal pressure sterilizer and keep it for 10 hours until the temperature inside the cylindrical culture medium bag drops below 25°C.

[0059] S3. In a sterile environment, inoculate the edible fungi strains at both ends and the center of the sterilized culture medium bag; select vigorous, robust, and suitable edible fungi strains without contamination by other bacteria. In a sterile or nearly sterile room, use an inoculation hoe to inoculate the strains at both ends and the center of the culture medium bag, with the inoculation amount being 7% of the culture medium mass.

[0060] S4. The inoculated culture medium bags are stacked in a greenhouse and fermented and cultivated for 90 days to obtain selenium-rich Ganoderma lucidum. During the cultivation process, spraying water is used in the greenhouse, and proper ventilation is maintained to keep the temperature in the greenhouse at 15°C to 25°C and the humidity at 85 to 95%.

[0061] Comparative Example 1:

[0062] The difference from Experiment 1 is that the biochar in Experiment 1 is removed.

[0063] Comparative Example 2:

[0064] The difference from Experiment 1 is that the selenium-enriched wheat and selenium-enriched rice in Example 1 are removed.

[0065] Comparative Example 3:

[0066] The difference from Experiment 1 is that no biochar, selenium-enriched wheat or selenium-enriched rice was added, and selenium fertilizer was sprayed after the edible fungi grew mycelium, with the amount of selenium fertilizer added being 1.2% of the mass of the culture medium.

[0067] The total selenium content was tested according to GB 5009.93-2017 “Determination of Selenium in Foods”, and the inorganic and organic selenium contents were tested according to T / SDAQI 037-2021 “Determination of Organic Selenium in Cereals”. The selenium content results of selenium-enriched wheat and selenium-enriched rice are shown in Table 1.

[0068] Table 1: Selenium content of selenium-enriched wheat and selenium-enriched rice

[0069]

[0070] As shown in Table 1, the total selenium and organic selenium content of wheat are both 0.13 mg / kg, which meets the requirements of the T / FXXH 011-2020 "Selenium-enriched wheat" standard. The total selenium and organic selenium content of rice are both 0.18 mg / kg, which meets the requirements of the GB / T 22499-2008 "Selenium-enriched rice" standard.

[0071] Further testing of organic selenium in selenium-enriched wheat and selenium-enriched rice revealed that organic selenium includes selenoamino acids composed of selenium-containing amino acids such as selenomethionine, selenocysteine, selenomethylselenocysteine, and their derivatives. These compounds have high biological activity and nutritional value and are easier to be absorbed and utilized by the human body.

[0072] The edible fungus Ganoderma lucidum cultivated in Experiment 1, Experiment 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3 were dried to a moisture content of 9-10%, and then the contents of total selenium, inorganic selenium and organic selenium were tested. The content of selenoamino acids was tested in accordance with GH / T1135-2017 "Selenium-rich agricultural products", the polysaccharide content of Ganoderma lucidum was tested in accordance with NY / T 1676-2023 "Determination of crude polysaccharides in edible fungi", and the protein content of Ganoderma lucidum was tested in accordance with GB 5009.5-2016 "Determination of protein in food". The results are shown in Table 2.

[0073] Table 2: Nutritional content of dried edible fungi Ganoderma lucidum

[0074]

[0075] It can be seen from Table 2 that in the dried edible fungi Ganoderma lucidum cultivated in Experiment 1, Experiment 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3:

[0076] Selenium content: total selenium content was 3.25mg / kg, 3.34mg / kg, 2.78mg / kg, 0.01mg / kg and 2.78mg / kg respectively. Of which, organic selenium content accounted for 100%, 100%, 100%, 100% and 42.8% of the total selenium content respectively, and selenoamino acid content accounted for 72.3%, 71.0%, 39.8%, 43.5% and 13.3% of the total selenium content respectively.

[0077] It can be seen that the organic selenium in the selenium-enriched edible fungi cultivated by selenium-enriched wheat and selenium-enriched rice reached 100%. This shows that when the edible fungi are cultivated in the culture medium bacteria bag made of selenium-enriched wheat and selenium-enriched rice, the edible fungi absorb the organic selenium in the selenium-enriched wheat and selenium-enriched rice in the culture medium bacteria bag into the edible fungi Ganoderma lucidum through microbial metabolism, fermentation and biochemical reactions during the cultivation and growth process. Most of the selenium-enriched edible fungi Ganoderma lucidum cultivated by spraying selenium fertilizer in comparative example 3 exist in the form of inorganic selenium, which is not conducive to human absorption, and long-term consumption is more harmful to the human body.

[0078] The polysaccharide contents are as follows: the polysaccharide contents are 7.35g / 100g, 7.67g / 100g, 6.87g / 100g, 6.92g / 100g and 4.15g / 100g respectively. The polysaccharide contents in Experiment 1 are 6.5%, 5.9% and 43.5% higher than those in Comparative Example 1, Comparative Example 2 and Comparative Example 3 respectively.

[0079] The protein content is as follows: the protein contents are 10.23g / 100g, 9.86g / 100g, 9.25g / 100g, 8.83g / 100g and 8.34g / 100g respectively. The protein content in Experiment 1 is 9.6%, 13.7% and 18.5% higher than that in Comparative Example 1, Comparative Example 2 and Comparative Example 3 respectively.

[0080] It can be seen that the polysaccharide and protein contents of Ganoderma lucidum cultivated in Comparative Examples 1, 2, and 3 are lower than those in Experiments 1 and 2. This shows that the porous structure of biochar can absorb and retain a large amount of water, improve the water retention rate of the culture medium, reduce the evaporation and loss of water, and promote the absorption and utilization of nutrients in the strains. At the same time, biochar can provide a carbon source for the culture medium and increase the polysaccharide and protein content of edible fungi. Adding selenium-enriched wheat and selenium-enriched rice not only increases the organic selenium content of edible fungi Ganoderma lucidum, but also increases the polysaccharide and protein content of Ganoderma lucidum, thereby improving the nutritional value of Ganoderma lucidum.

[0081] In summary, the present invention adds biochar to the culture medium bag, and also adds selenium-rich wheat and selenium-rich rice. The edible fungi cultivated after inoculation of the strains have a high content of organic selenium, and at the same time, the content of nutrients such as polysaccharides and proteins in the edible fungi is increased. The selenium-rich edible fungi have broad market prospects.

[0082] After cultivating the strains, we get selenium-rich Ganoderma lucidum. When Ganoderma lucidum matures, it will eject an extremely tiny oval reproductive cell from the pores under the cap. This is the seed of Ganoderma lucidum. The essence of Ganoderma lucidum can be collected artificially to obtain health products that can resist oxidation, enhance immunity, prevent cardiovascular diseases and cancer, etc.

[0083] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A method for cultivating selenium-enriched edible fungi, characterized in that: The following steps are involved: S1. preparing a culture medium bacterial bag; wherein the culture medium bacterial bag comprises selenium-rich crops, sawdust, cottonseed hulls, soybean meal and biochar; the selenium-rich crops comprise selenium-rich wheat and / or selenium-rich rice; S2. Sterilizing the culture medium bag; S3. In a sterile environment, the edible fungus strains are inoculated at both ends and the center of the sterilized culture medium bag; S4. The inoculated culture medium bacteria bags are stacked in a greenhouse and fermented and cultivated for 60 to 90 days to obtain selenium-rich edible fungi.

2. The method for cultivating selenium-rich edible fungi according to claim 1, characterized in that: The preparation of the culture medium bacteria bag comprises: 20-22 parts by weight of selenium-enriched wheat, 16-20 parts by weight of selenium-enriched rice, and 5-8 parts by weight of biochar, and mixing them; The mixed selenium-enriched wheat, selenium-enriched rice, sawdust, cottonseed husk, soybean meal and biochar are put into a cylindrical breathable gauze bag to obtain a cylindrical culture medium bag.

3. The method for cultivating selenium-rich edible fungi according to claim 2, characterized in that: Before weighing the selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk, the method further includes: crushing the selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk so that the particle sizes of the selenium-enriched wheat, selenium-enriched rice, sawdust and cottonseed husk are all greater than or equal to 0.8 mm and less than or equal to 1.2 mm.

4. The method for cultivating selenium-enriched edible fungi according to claim 3, characterized in that: The production of the biochar comprises: Weigh 28 to 32 parts by weight of nut shells, 20 to 25 parts by weight of sawdust, and 18 to 20 parts by weight of rice husks, and mix them; Placing the mixed nut shells, sawdust and rice husks in a carbonization furnace, filling the carbonization furnace with nitrogen, and heating at a rate of 5° C. / min until the temperature in the carbonization furnace is between 520° C. and 540° C.; The nut shells, the wood chips and the rice husks are carbonized in the carbonization furnace for 2 hours to 2.5 hours to obtain the biochar.

5. The method for cultivating selenium-enriched edible fungi according to claim 4, characterized in that: The mass ratio of peanut shell, walnut shell and almond shell in the nut shell is 2:2:

1.

6. The method for cultivating selenium-rich edible fungi according to claim 4, characterized in that: Before weighing the nut shells and sawdust, the method further comprises: The nut shells and wood chips are crushed so that the particle sizes are greater than or equal to 1.5 mm and less than or equal to 2.0 mm.

7. The method for cultivating selenium-rich edible fungi according to claim 2, characterized in that: The sterilization treatment of the culture medium bacteria bag comprises: The cylindrical culture medium bag is placed in a normal pressure sterilizer, and purified water is added; Heat the purified water until it boils, and continue heating for 7 to 8 hours; Close the normal pressure sterilizer and keep it for 8 to 10 hours until the temperature in the cylindrical culture medium bag drops below 25°C.

8. The method for cultivating selenium-enriched edible fungi according to claim 1, characterized in that: Before inoculating the edible fungus strains into the two ends and the center of the sterilized culture medium bag, the method further comprises: Choose edible fungi strains of the right season that are vigorous, strong, and free of contamination from other bacteria.

9. The method for cultivating selenium-enriched edible fungi according to claim 1, characterized in that: During the fermentation and cultivation process, the greenhouse is properly ventilated and watered to control the temperature and humidity in the greenhouse. The temperature T in the greenhouse satisfies: 15°C ≤ T ≤ 25°C, and the humidity %RH in the greenhouse satisfies: 85% ≤ %RH ≤ 95%.

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