Culture method and application of selenium-enriched cordyceps militaris mycelium

Abstract

The invention relates to the technical field of mycelium culture, in particular to a culture method and application of selenium-enriched cordyceps militaris mycelium. The culture method comprises the following steps: carrying out PAD culture medium culture, shake-flask culture and fermentation tank aerated culture on a cordyceps militaris mother strain to obtain a cordyceps militaris liquid strain; inoculating the cordyceps militaris liquid strain into a liquid culture medium for aerated culture to obtain selenium-rich organic selenium cordyceps militaris liquid; the preparation method comprises the following steps: respectively crushing soybeans, wheat and corn, mixing to obtain mixed powder, soaking the mixed powder with water, and airing to obtain a solid culture medium; and inoculating the selenium-rich organic selenium cordyceps militaris bacterial liquid into a solid culture medium for aerated culture to obtain selenium-rich cordyceps militaris mycelia. The culture method is simple in step and easy to operate, the selenium content of the cultured selenium-enriched cordyceps militaris mycelium is high, and the culture method has wide application prospects in food, health care products, traditional Chinese medicinal materials and feed.

Description

Technical Field

[0001] The invention relates to the technical field of mycelium cultivation, and in particular to a cultivation method and application of selenium-enriched Cordyceps militaris mycelium. Background Art

[0002] Cordyceps militaris, also known as northern cordyceps, belongs to Eumycota, Ascomycotina, Pyrenomycetes, Clavicipitales, Clavicipitaceae, Cordyceps, and is a different species of the same genus as Cordyceps sinensis. It is the model species of the genus Cordyceps. A large number of studies have shown that the pharmacological effects of Cordyceps militaris are very similar to those of Cordyceps sinensis. The content of its medicinal ingredients, cordycepic acid, cordyceps polysaccharides, cordycepin, and SOD activity are all higher than those of Cordyceps sinensis. It has the effects of anti-tumor, anti-fatigue, hypoglycemic, anti-bacterial and anti-inflammatory, and improving immunity.

[0003] Selenium is an essential trace element for the human body. It is also internationally recognized as the "king of anti-cancer elements" and "human immune activator". It plays a very important role in human health. It participates in the synthesis of various selenium-containing enzymes and selenoproteins in the human body and has multiple biological functions. For most people, an appropriate amount of selenium supplementation is of positive significance for maintaining good health and preventing certain diseases. However, the selenium existing in the soil and water in nature is inorganic selenium, which has toxic side effects. It can only be consumed by humans after being converted into safe and non-toxic organic selenium by plants, animals or microorganisms.

[0004] As a carrier for enriching selenium, Cordyceps militaris has strong selenium resistance and selenium aggregation capabilities. It can bind inorganic selenium to macromolecular active substances (such as proteins and polysaccharides) through the transformation of material metabolism in mycelial cells, and convert it into organic forms of selenium such as protein selenium and polysaccharide selenium. Selenium polysaccharides can be used as immunomodulators and health products for cancer prevention and antiviral treatment. They also have unique functions in removing active oxidative free radicals, thereby preventing the human body from inflammation, aging, tumors, immune damage, certain drug toxicity and other diseases caused by oxidative free radicals. Therefore, studying the organic combination of Cordyceps militaris and selenium can make selenium and the physiologically active substances in Cordyceps militaris synergistically enhance the effect, effectively improve the nutrition and health care effects of Cordyceps militaris, and develop selenium-enriched Cordyceps militaris of great significance. Summary of the invention

[0005] In order to solve the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a method for culturing selenium-enriched Cordyceps militaris mycelium and its application. The method for culturing selenium-enriched Cordyceps militaris mycelium is simple to operate, short in cycle, low in cost, green and environmentally friendly, and the cultivated Cordyceps militaris mycelium has a high selenium content and has broad application prospects.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for culturing selenium-enriched Cordyceps militaris mycelium comprises the following steps:

[0008] S1, culturing the mother strain of Cordyceps militaris through PAD medium, shaking flask culture and fermentation tank aeration culture to obtain liquid strain of Cordyceps militaris;

[0009] S2, inoculating the Cordyceps militaris liquid strain in S1 into a liquid culture medium for aeration culture to obtain a selenium-rich organic selenium Cordyceps militaris liquid;

[0010] S3, respectively grinding soybean, wheat and corn and mixing them to obtain a mixed powder, soaking the mixed powder in water, and drying to obtain a solid culture medium;

[0011] S4. Inoculate the selenium-rich organic selenium Cordyceps militaris liquid of S2 into the solid culture medium of S3 under sterile conditions to carry out the first culture; take the Cordyceps militaris mycelium after the first culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the second culture; take the Cordyceps militaris mycelium after the second culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the third culture to obtain selenium-rich Cordyceps militaris mycelium.

[0012] The invention combines liquid fermentation with solid fermentation to cultivate selenium-enriched Cordyceps militaris mycelium, and has the advantages of simple operation and good selenium-enriched effect; the Cordyceps militaris mycelium is high in protein and polysaccharide content, and has the effects of anti-tumor, anti-fatigue, hypoglycemic, antibacterial and anti-inflammatory, immunity-enhancing and the like; Cordyceps militaris is used as a selenium-enriched carrier to convert inorganic selenium into organic selenium, and the absorption conversion rate is as high as 90-99%, the selenium content of each kilogram of Cordyceps militaris is as high as 1800 mg, and the organic selenium content accounts for as high as 98% of the total selenium content, providing a new idea for developing selenium-enriched food and health products, Chinese medicinal materials and feed.

[0013] Further, in the S2, the liquid culture medium includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal, 4-6 parts of white sugar, 0.07-0.09 parts of peptone, 0.07-0.09 parts of potassium dihydrogen sulfate, 0.07-0.09 parts of magnesium sulfate, 0.1-0.5 parts of selenium-rich microcapsules and 900-1100 parts of water, and the temperature of the liquid culture medium aeration culture is 23-25 ​​° C, and the aeration is sterile air, the pressure is 0.1-0.2MPa, and the time is 7-15 days. The liquid culture medium in the present invention utilizes selenium-rich microcapsules to have a sustained release effect, so that the liquid culture medium can continuously and stably release the selenium source, and Cordyceps militaris converts the inorganic selenium source into organic selenium, thereby increasing the organic selenium content of the Cordyceps militaris mycelium.

[0014] Furthermore, the selenium-rich microcapsules include the following raw materials in parts by weight: 0.1-0.5 parts of sodium selenite, 1-5 parts of isophorone diisocyanate, 6-10 parts of accelerator, 1-5 parts of emulsifier, 0.5-2 parts of catalyst and 30-80 parts of water.

[0015] Furthermore, the accelerator is zinc sulfate or zinc acetate, the emulsifier is polyvinyl alcohol or polyvinyl pyrrolidone, and the catalyst is tetramethylethylenediamine or pentamethyldiethylenetriamine.

[0016] Enter

[0017] In one step, the preparation method of the selenium-rich microcapsules comprises the following steps: (1) preparing an aqueous phase: mixing an emulsifier and water according to parts by weight and stirring evenly; (2) preparing an oil phase: mixing sodium selenite, an accelerator and isophorone diisocyanate according to parts by weight and stirring evenly; (3) preparing an oil-in-water emulsion: mixing an aqueous phase and an oil phase and stirring evenly; (4) preparing selenium-rich microcapsules: mixing an aqueous phase and an oil phase according to parts by weight and stirring evenly;

[0018] The oil-in-water emulsion and the catalyst are mixed according to weight, stirred evenly, and reacted at 80-100° C. for 2-6 hours. The present invention uses sodium selenite and a promoter as the core material, polyurea as the microcapsule wall material, and utilizes the advantages of good sustained-release performance and high embedding rate of the microcapsule, so that sodium selenite and the promoter can be slowly released in the liquid culture medium, and promote the enrichment of selenium in Cordyceps militaris; at the same time, a promoter containing zinc is added, and zinc can promote the enrichment of selenium in Cordyceps militaris under the condition of the presence of zinc and low selenium concentration. In the mycelium of Cordyceps militaris, selenium is mainly combined with protein, and zinc is mainly combined with polysaccharide, so that Cordyceps militaris can simultaneously enrich selenium and zinc.

[0019] Furthermore, in S1, the culture medium for shake flask culture includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal powder, 4-6 parts of white sugar, 0.07-0.09 parts of yeast extract, 0.07-0.09 parts of potassium dihydrogen phosphate, 0.07-0.09 parts of magnesium sulfate and 900-1100 parts of water.

[0020] Furthermore, in S1, the culture medium for aeration culture in the fermentation tank includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal powder, 4-6 parts of white sugar, 0.1-0.2 parts of peptone, 0.05-0.2 parts of potassium dihydrogen phosphate, 0.05-0.1 parts of magnesium sulfate and 900-1100 parts of water. The temperature of aeration culture in the fermentation tank is 23-25°C, the aeration is sterile air, the pressure is 0.1-0.2MPa, and the time is 5-10 days.

[0021] Furthermore, in S3, the weight ratio of soybean, wheat and corn is 4-8:20-30:60-80, and the weight ratio of mixed powder and water is 1:40-50.

[0022] Furthermore, the particle size of the soybean, wheat and corn is 4-8 mm.

[0023] Further, in the S4, the temperature of the first culture is 23-25°C, the time of the first culture is 10-15 days, the temperature of the second culture is 23-25°C, the time of the second culture is 10-15 days, the temperature of the third culture is 23-25°C, and the time of the third culture is 10-15 days. The present invention effectively increases the biomass of Cordyceps militaris mycelium by repeating the culture three times, improves the yield of Cordyceps militaris mycelium, and increases the content of cordycepin and other effective ingredients in the Cordyceps militaris mycelium.

[0024] The present invention also provides a selenium-rich Cordyceps militaris mycelium, and the selenium-rich Cordyceps militaris mycelium is obtained by the above-mentioned culturing method of the selenium-rich Cordyceps militaris mycelium.

[0025] The present invention also provides the use of selenium-enriched Cordyceps militaris mycelium in the preparation of food, health products, Chinese medicinal materials and feed.

[0026] The beneficial effects of the present invention are:

[0027] The method for culturing selenium-enriched Cordyceps militaris mycelia of the invention comprises the following steps: subjecting Cordyceps militaris mother strains to PAD culture medium, shaking flask culture and fermentation tank aeration culture to obtain Cordyceps militaris liquid strains, inoculating the strains into a liquid culture medium to obtain selenium-enriched organic selenium Cordyceps militaris bacterial liquid, and then inoculating the selenium-enriched organic selenium Cordyceps militaris bacterial liquid into a solid culture medium to obtain selenium-enriched Cordyceps militaris mycelia; the selenium-enriched microcapsules in the liquid culture medium have a good sustained-release effect, can continuously and effectively release selenium, so that Cordyceps militaris can convert inorganic selenium into organic selenium, thereby realizing the enrichment of selenium; the culturing method has simple steps and is easy to operate; the cultured selenium-enriched Cordyceps militaris mycelia has high selenium content, and has broad application prospects in food, health products, Chinese medicinal materials and feed. DETAILED DESCRIPTION

[0028] The present invention will be described below in conjunction with specific embodiments, and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments are used to illustrate the present invention, rather than to limit the present invention.

[0029] Example 1

[0030] In this embodiment, a method for culturing selenium-enriched Cordyceps militaris mycelium comprises the following steps:

[0031] S1, culturing the mother strain of Cordyceps militaris through PAD medium, shaking flask culture and fermentation tank aeration culture to obtain liquid strain of Cordyceps militaris;

[0032] S2, inoculating the Cordyceps militaris liquid strain in S1 into a liquid culture medium for aeration culture to obtain a selenium-rich organic selenium Cordyceps militaris liquid;

[0033] S3, respectively grinding soybean, wheat and corn and mixing them to obtain a mixed powder, soaking the mixed powder in water, and drying to obtain a solid culture medium;

[0034] S4. Inoculate the selenium-rich organic selenium Cordyceps militaris liquid of S2 into the solid culture medium of S3 under sterile conditions to carry out the first culture; take the Cordyceps militaris mycelium after the first culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the second culture; take the Cordyceps militaris mycelium after the second culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the third culture to obtain selenium-rich Cordyceps militaris mycelium.

[0035] Furthermore, in S2, the liquid culture medium includes the following raw materials in parts by weight: 0.4 parts of soybean meal powder, 5 parts of white sugar, 0.08 parts of peptone, 0.08 parts of potassium dihydrogen sulfate, 0.08 parts of magnesium sulfate, 0.3 parts of selenium-rich microcapsules and 1000 parts of water. The temperature of aeration culture of the liquid culture medium is 24°C, the aeration is sterile air, the pressure is 0.15 MPa, and the time is 11 days.

[0036] Furthermore, the selenium-rich microcapsules include the following raw materials in parts by weight: 0.3 parts of sodium selenite, 3 parts of isophorone diisocyanate, 8 parts of accelerator, 3 parts of emulsifier, 1 part of catalyst and 60 parts of water.

[0037] Furthermore, the accelerator is zinc sulfate, the emulsifier is polyvinyl alcohol, and the catalyst is tetramethylethylenediamine.

[0038] Furthermore, the preparation method of the selenium-rich microcapsules includes the following steps: (1) preparing an aqueous phase: mixing an emulsifier and water according to parts by weight and stirring evenly; (2) preparing an oil phase: mixing sodium selenite, an accelerator and isophorone diisocyanate according to parts by weight and stirring evenly; (3) preparing an oil-in-water emulsion: mixing an aqueous phase and an oil phase and stirring evenly; (4) preparing selenium-rich microcapsules: mixing an oil-in-water emulsion and a catalyst according to parts by weight, stirring evenly, and reacting at 90°C for 4 hours.

[0039] Furthermore, in S1, the culture medium for shake flask culture includes the following raw materials in parts by weight: 0.4 parts of soybean meal powder, 5 parts of white sugar, 0.08 parts of yeast extract, 0.08 parts of potassium dihydrogen phosphate, 0.08 parts of magnesium sulfate and 1000 parts of water.

[0040] Furthermore, in S1, the culture medium for aeration culture in the fermentation tank includes the following raw materials in parts by weight: 0.4 parts of soybean meal powder, 5 parts of white sugar, 0.15 parts of peptone, 0.1 parts of potassium dihydrogen phosphate, 0.07 parts of magnesium sulfate and 1000 parts of water. The temperature of aeration culture in the fermentation tank is 24°C, the aeration is sterile air, the pressure is 0.15 MPa, and the time is 7 days.

[0041] Furthermore, in S3, the weight ratio of soybean, wheat and corn is 5:25:70, and the weight ratio of mixed powder and water is 1:45.

[0042] Furthermore, the particle size of the soybean, wheat and corn is 6 mm.

[0043] Furthermore, in S4, the temperature of the first culture is 24° C., the time of the first culture is 13 days, the temperature of the second culture is 24° C., the time of the second culture is 13 days, and the temperature of the third culture is 24° C., the time of the third culture is 13 days.

[0044] Example 2

[0045] In this embodiment, a method for culturing selenium-enriched Cordyceps militaris mycelium comprises the following steps:

[0046] S1, culturing the mother strain of Cordyceps militaris through PAD medium, shaking flask culture and fermentation tank aeration culture to obtain liquid strain of Cordyceps militaris;

[0047] S2, inoculating the Cordyceps militaris liquid strain in S1 into a liquid culture medium for aeration culture to obtain a selenium-rich organic selenium Cordyceps militaris liquid;

[0048] S3, respectively grinding soybean, wheat and corn and mixing them to obtain a mixed powder, soaking the mixed powder in water, and drying to obtain a solid culture medium;

[0049] S4. Inoculate the selenium-rich organic selenium Cordyceps militaris liquid of S2 into the solid culture medium of S3 under sterile conditions to carry out the first culture; take the Cordyceps militaris mycelium after the first culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the second culture; take the Cordyceps militaris mycelium after the second culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the third culture to obtain selenium-rich Cordyceps militaris mycelium.

[0050] Furthermore, in S2, the liquid culture medium includes the following raw materials in parts by weight: 0.2 parts of soybean meal powder, 4 parts of white sugar, 0.07 parts of peptone, 0.07 parts of potassium dihydrogen sulfate, 0.07 parts of magnesium sulfate, 0.1 parts of selenium-rich microcapsules and 900 parts of water. The temperature of aeration culture of the liquid culture medium is 23°C, the aeration is sterile air, the pressure is 0.1 MPa, and the time is 7 days.

[0051] Furthermore, the selenium-rich microcapsules include the following raw materials in parts by weight: 0.1 parts of sodium selenite, 2 parts of isophorone diisocyanate, 6 parts of accelerator, 2 parts of emulsifier, 0.5 parts of catalyst and 30 parts of water.

[0052] Furthermore, the accelerator is zinc acetate, the emulsifier is polyvinyl pyrrolidone, and the catalyst is pentamethyldiethylenetriamine.

[0053] Furthermore, the preparation method of the selenium-rich microcapsules comprises the following steps: (1) preparing an aqueous phase: mixing an emulsifier and water according to parts by weight and stirring evenly; (2) preparing an oil phase: mixing sodium selenite, an accelerator and isophorone diisocyanate according to parts by weight and stirring evenly; (3) preparing an oil-in-water emulsion: mixing an aqueous phase and an oil phase and stirring evenly; (4) preparing selenium-rich microcapsules: mixing an oil-in-water emulsion and a catalyst according to parts by weight, stirring evenly, and reacting at 80° C. for 2 hours.

[0054] Furthermore, in S1, the culture medium for shake flask culture includes the following raw materials in parts by weight: 0.2 parts of soybean meal powder, 4 parts of white sugar, 0.07 parts of yeast extract, 0.07 parts of potassium dihydrogen phosphate, 0.07 parts of magnesium sulfate and 900 parts of water.

[0055] Furthermore, in S1, the culture medium for aeration culture in the fermentation tank includes the following raw materials in parts by weight: 0.2 parts of soybean meal powder, 4 parts of white sugar, 0.1 parts of peptone, 0.07 parts of potassium dihydrogen phosphate, 0.07 parts of magnesium sulfate and 900 parts of water. The temperature of aeration culture in the fermentation tank is 23°C, the gas is sterile air, the pressure is 0.1 MPa, and the time is 6 days.

[0056] Furthermore, in S3, the weight ratio of soybean, wheat and corn is 4:20:60, and the weight ratio of mixed powder and water is 1:40.

[0057] Furthermore, the particle size of the soybean, wheat and corn is 4 mm.

[0058] Furthermore, in S4, the temperature of the first culture is 23° C., the time of the first culture is 10 days, the temperature of the second culture is 23° C., the time of the second culture is 10 days, and the temperature of the third culture is 23° C., the time of the third culture is 10 days.

[0059] Example 3

[0060] In this embodiment, a method for culturing selenium-enriched Cordyceps militaris mycelium comprises the following steps:

[0061] S1, culturing the mother strain of Cordyceps militaris through PAD medium, shaking flask culture and fermentation tank aeration culture to obtain liquid strain of Cordyceps militaris;

[0062] S2, inoculating the Cordyceps militaris liquid strain in S1 into a liquid culture medium for aeration culture to obtain a selenium-rich organic selenium Cordyceps militaris liquid;

[0063] S3, respectively grinding soybean, wheat and corn and mixing them to obtain a mixed powder, soaking the mixed powder in water, and drying to obtain a solid culture medium;

[0064] S4. Inoculate the selenium-rich organic selenium Cordyceps militaris liquid of S2 into the solid culture medium of S3 under sterile conditions to carry out the first culture; take the Cordyceps militaris mycelium after the first culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the second culture; take the Cordyceps militaris mycelium after the second culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the third culture to obtain selenium-rich Cordyceps militaris mycelium.

[0065] Furthermore, in S2, the liquid culture medium includes the following raw materials in parts by weight: 0.6 parts of soybean meal powder, 6 parts of white sugar, 0.09 parts of peptone, 0.09 parts of potassium dihydrogen sulfate, 0.09 parts of magnesium sulfate, 0.45 parts of selenium-rich microcapsules and 1100 parts of water. The temperature of aeration culture of the liquid culture medium is 25°C, the aeration is sterile air, the pressure is 0.2 MPa, and the time is 15 days.

[0066] Furthermore, the selenium-rich microcapsules include the following raw materials in parts by weight: 0.5 parts of sodium selenite, 5 parts of isophorone diisocyanate, 8 parts of accelerator, 5 parts of emulsifier, 1.5 parts of catalyst and 80 parts of water.

[0067] Furthermore, the accelerator is zinc sulfate, the emulsifier is polyvinyl alcohol, and the catalyst is tetramethylethylenediamine.

[0068] Furthermore, the preparation method of the selenium-rich microcapsules comprises the following steps: (1) preparing an aqueous phase: mixing an emulsifier and water according to parts by weight and stirring evenly; (2) preparing an oil phase: mixing sodium selenite, an accelerator and isophorone diisocyanate according to parts by weight and stirring evenly; (3) preparing an oil-in-water emulsion: mixing an aqueous phase and an oil phase and stirring evenly; (4) preparing selenium-rich microcapsules: mixing an oil-in-water emulsion and a catalyst according to parts by weight, stirring evenly, and reacting at 100° C. for 6 hours.

[0069] Furthermore, in S1, the culture medium for shake flask culture includes the following raw materials in parts by weight: 0.6 parts of soybean meal powder, 6 parts of white sugar, 0.09 parts of yeast extract, 0.09 parts of potassium dihydrogen phosphate, 0.09 parts of magnesium sulfate and 1100 parts of water.

[0070] Furthermore, in S1, the culture medium for aeration culture in the fermenter includes the following raw materials in parts by weight: 0.5 parts of soybean meal powder, 5.5 parts of white sugar, 0.2 parts of peptone, 0.2 parts of potassium dihydrogen phosphate, 0.1 parts of magnesium sulfate and 1100 parts of water. The temperature of aeration culture in the fermenter is 25°C, the gas is sterile air, the pressure is 0.2 MPa, and the time is 10 days.

[0071] Furthermore, in S3, the weight ratio of soybean, wheat and corn is 7:30:80, and the weight ratio of mixed powder and water is 1:50.

[0072] Furthermore, the particle size of the soybean, wheat and corn is 8 mm.

[0073] Furthermore, in S4, the temperature of the first culture is 25° C., the time of the first culture is 15 days, the temperature of the second culture is 25° C., the time of the second culture is 15 days, and the temperature of the third culture is 25° C., the time of the third culture is 15 days.

[0074] Example 4

[0075] In this embodiment, the selenium-rich Cordyceps militaris mycelia obtained in Examples 1-3 and the culture medium full of mycelia are dried or sun-dried, and then crushed into 120-300 mesh fine powder to obtain selenium-rich Cordyceps militaris mycelia powder. The Cordyceps militaris mycelia powder can be used to prepare selenium-rich health products.

[0076] The total arsenic, lead, total mercury and cadmium contents and the pesticide residues of 666 and DDT in the Cordyceps militaris mycelium in Example 1 were tested, and the test results are shown in Table 1 below:

[0077]

[0078] As shown in Table 1, the selenium content of the Cordyceps militaris mycelium obtained by the cultivation method of the present invention is not detected in total arsenic, lead, and total mercury, the cadmium content is lower than the amount specified by the national standard, and no pesticide residues of hexachlorocyclohexane and DDT are detected, so it is safe to eat.

[0079] The Cordyceps militaris mycelium in Example 1-3 was placed in a drying oven at 80° C., and then the selenium content was measured according to GB / T5009.93-2003, and the zinc content was measured according to GB 5009.14-2017. The test results are shown in Table 2 below:

[0080] Serial number Selenium, mg / kg Organic selenium mass percentage, % Zinc, mg / kg Example 1 <![CDATA[2.32*10 3 ]]> 98.7 <![CDATA[1.21*10 6 ]]> Example 2 <![CDATA[2.19*10 3 ]]> 98.2 <![CDATA[1.14*10 6 <!-- 6 -->]]> Example 3 <![CDATA[2.25*10 3 ]]> 98.5 <![CDATA[1.18*10 6 ]]>

[0081] As can be seen from Table 1-2, the liquid culture medium of the present invention utilizes selenium-rich microcapsules with a sustained release effect, so that the liquid culture medium can continuously and stably release the selenium source, Cordyceps militaris converts the inorganic selenium source into organic selenium, and the organic selenium content of the Cordyceps militaris mycelium is increased; the selenium-rich microcapsules use sodium selenite and a promoter as the core material, and polyurea as the microcapsule wall material, and utilize the advantages of good sustained release performance and high embedding rate of the microcapsules, so that sodium selenite and the promoter can be slowly released in the liquid culture medium, and the enrichment of selenium in Cordyceps militaris is promoted; at the same time, a promoter containing zinc is added, and in the presence of zinc and low selenium concentration, zinc can promote the enrichment of selenium in Cordyceps militaris.

[0082] The method for culturing the selenium-rich Cordyceps militaris mycelium of the present invention is simple to operate, short in cycle, low in cost, and environmentally friendly; the cultured Cordyceps militaris mycelium has a high selenium content and has broad application prospects.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for cultivating selenium-enriched Cordyceps militaris mycelium, characterized in that: The steps include: S1, culturing the mother strain of Cordyceps militaris through PAD medium, shaking flask culture and fermentation tank aeration culture to obtain liquid strain of Cordyceps militaris; S2, inoculating the Cordyceps militaris liquid strain in S1 into a liquid culture medium for aeration culture to obtain a selenium-rich organic selenium Cordyceps militaris liquid; S3, respectively grinding soybean, wheat and corn and mixing them to obtain a mixed powder, soaking the mixed powder in water, and drying to obtain a solid culture medium; S4. Inoculate the selenium-rich organic selenium Cordyceps militaris liquid of S2 into the solid culture medium of S3 under sterile conditions to carry out the first culture; take the Cordyceps militaris mycelium after the first culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the second culture; take the Cordyceps militaris mycelium after the second culture, shake the solid culture medium under sterile conditions to make the Cordyceps militaris mycelium evenly dispersed on the surface of the solid culture medium, and carry out the third culture to obtain selenium-rich Cordyceps militaris mycelium.

2. The method for cultivating selenium-enriched Cordyceps militaris mycelium according to claim 1, characterized in that: In the S2, the liquid culture medium includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal powder, 4-6 parts of white sugar, 0.07-0.09 parts of peptone, 0.07-0.09 parts of potassium dihydrogen sulfate, 0.07-0.09 parts of magnesium sulfate, 0.1-0.5 parts of selenium-rich microcapsules and 900-1100 parts of water. The temperature of the liquid culture medium is aerated and cultured at 23-25°C, the aeration is sterile air, the pressure is 0.1-0.2MPa, and the time is 7-15 days.

3. The method for cultivating selenium-enriched Cordyceps militaris mycelium according to claim 2, characterized in that: The selenium-rich microcapsules include the following raw materials in parts by weight: 0.1-0.5 parts of sodium selenite, 1-5 parts of isophorone diisocyanate, 6-10 parts of accelerator, 1-5 parts of emulsifier, 0.5-2 parts of catalyst and 30-80 parts of water.

4. The method for culturing selenium-enriched Cordyceps militaris mycelium according to claim 3, characterized in that: The preparation method of the selenium-rich microcapsules comprises the following steps: (1) preparing an aqueous phase: mixing an emulsifier and water according to parts by weight and stirring evenly; (2) preparing an oil phase: mixing sodium selenite, an accelerator and isophorone diisocyanate according to parts by weight and stirring evenly; (3) preparing an oil-in-water emulsion: mixing an aqueous phase and an oil phase and stirring evenly; (4) preparing selenium-rich microcapsules: mixing an oil-in-water emulsion and a catalyst according to parts by weight, stirring evenly, and reacting at 80-100° C. for 2-6 hours.

5. The method for culturing selenium-enriched Cordyceps militaris mycelium according to claim 1, characterized in that: In S1, the culture medium for shake flask culture includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal powder, 4-6 parts of white sugar, 0.07-0.09 parts of yeast extract, 0.07-0.09 parts of potassium dihydrogen phosphate, 0.07-0.09 parts of magnesium sulfate and 900-1100 parts of water.

6. The method for culturing selenium-enriched Cordyceps militaris mycelium according to claim 1, characterized in that: In S1, the culture medium for aeration culture in the fermentation tank includes the following raw materials in parts by weight: 0.2-0.6 parts of soybean meal powder, 4-6 parts of white sugar, 0.1-0.2 parts of peptone, 0.05-0.2 parts of potassium dihydrogen phosphate, 0.05-0.1 parts of magnesium sulfate and 900-1100 parts of water. The temperature of aeration culture in the fermentation tank is 23-25°C, the aeration is sterile air, the pressure is 0.1-0.2MPa, and the time is 5-10 days.

7. The method for culturing selenium-enriched Cordyceps militaris mycelium according to claim 1, characterized in that: In the S3, the weight ratio of soybean, wheat and corn is 4-8:20-30:60-80, and the weight ratio of the mixed powder and water is 1:40-50.

8. The method for culturing selenium-enriched Cordyceps militaris mycelium according to claim 1, characterized in that: In S4, the first culture temperature is 23-25°C, the first culture time is 10-15 days, the second culture temperature is 23-25°C, the second culture time is 10-15 days, and the third culture temperature is 23-25°C, the third culture time is 10-15 days.

9. A selenium-enriched Cordyceps militaris mycelium, characterized in that: The selenium-enriched Cordyceps militaris mycelium is obtained by the culture method according to any one of claims 1 to 8.

10. Use of the mycelium according to claim 9 in preparing food, health products, Chinese medicinal materials and feed.

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