A method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice
After functional red koji fermentation, the protective agent and pulverization treatment of sodium alginate, sodium ethylenediaminetetraacetate and casein phosphopeptide are formed to form a stable ring-opening Monacorin K, and the ring-opening in the prior art is solved. The problems of low rate and instability improve the quality and safety of the product.
Patent Information
- Application Number
- CN202410572763.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2044-05-10
AI Technical Summary
The opening rate of Monacorin K in the existing functional red music is difficult to reach 50%-90%, and the opening form is unstable, which is easy to transform into a closed loop, affecting product quality.
After the functional red koji fermentation is completed, the sterilization is performed using a mixed protective agent of sodium alginate, sodium ethylenediaminetetraacetate and casein phosphopeptide, and then sprayed in the fermentation product, stirring evenly, then dried and crushed, and further passed through ultra-micrometer Crushing and dry granulation form small particles to form a protection system that is conducive to ring opening stability.
The open-loop ratio and stability of Monacorin K is significantly improved, the transition ratio from open-loop to closed-loop is reduced, the fermented substances are contaminated by mixed bacteria, and the quality and safety of the product are ensured.
Smart Images
Figure GDA0005075491210000071 
Figure GDA0005075491210000081
Abstract
Description
Technical Field
[0001] The invention relates to the technical fields of bioengineering and health food, and in particular to a method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice. Background Art
[0002] Red yeast rice is a traditional Chinese medicine health product that can be used for both food and treatment. It was first used in the Tang Dynasty and has a history of more than a thousand years. Li Shizhen of the Ming Dynasty recorded in Compendium of Materia Medica that red yeast rice can help digestion and promote blood circulation, strengthen the spleen and dry the stomach, treat injuries from falls, as well as blood and qi pain in women and postpartum blood.
[0003] Red yeast rice is a product fermented by Monascus purpureus with rice as the main raw material. Modern science has further revealed that red yeast rice has other unique effects. In 1979, Japanese scholar Endo Akira discovered that red yeast rice contains a lipid regulator, HMG-COA reductase inhibitor (monacolin K), and believed that this is the main active ingredient of red yeast rice. Monacolin K can competitively block the synthesis of total cholesterol in the liver, reduce serum total cholesterol (TC), and can reduce triglycerides (TG) and low-density lipoprotein (LDL-C), and increase high-density lipoprotein (HDL-C). Therefore, red yeast rice can lower cholesterol and prevent cardiovascular diseases.
[0004] Monacolin K (also called lovastatin) in functional red yeast rice contains two structures: lactone closed-ring and acid open-ring. The closed-ring monacolin K itself is inactive and needs to be hydrolyzed by the hydroxyesterase produced by the human body to become acid open-ring monacolin K to take effect, which can cause damage to the liver and kidneys. The latter does not require the participation of the human body's hydroxyesterase and can be directly absorbed and take effect without causing damage to the liver and kidneys.
[0005] Most manufacturers claim that the ring-opening rate of monacolin in functional red yeast rice is 50%-90%, but in fact many manufacturers cannot reach this level, and the ring-opening rate of most manufacturers' products is less than 50%. Some manufacturers have a lower fermentation level and achieve the content of functional red yeast rice statins by adding extracted lovastatin, and the added statins are basically closed-loop.
[0006] More importantly, the acidic open-ring monacolin K is unstable and can easily change from an open ring to a closed ring during production, processing and storage of finished products. Therefore, the ring-opening rate of existing functional red yeast monacolin is gradually reduced after production. Therefore, it is of great significance to improve the ring-opening rate of monacolin in the functional red yeast during the production process and to stabilize the ring-opening rate of monacolin in the functional red yeast product after production.
[0007] The technical solution published in the Chinese invention patent "A method for controlling the ring-opening ratio of monacolin K in functional red yeast rice" with patent application number 201110389452.X is: during the fermentation process of functional red yeast rice, the additive is sprayed onto the solid fermentation product using an ultrasonic atomization device. However, to obtain solid-state fermented functional red yeast rice with qualified quality, it is currently sterilized and fermented together with the culture medium in a specific container. The fermentation process does not allow the growth of foreign bacteria, otherwise the content of monacolin K in the product cannot be guaranteed, and it may cause excessive toxins such as citrinin and aflatoxin. The additives added in this solution are not sterilized and need to be added using ultrasonic atomization, which obviously has major defects for the fermentation of functional red yeast rice that requires aseptic operation. Summary of the invention
[0008] The technical problem to be solved by the present invention is to provide a method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice.
[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: to provide a method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, comprising the following steps:
[0010] Step 1: After the functional red yeast fermentation is completed, a red yeast fermentation product is obtained, and an aqueous solution prepared by mixing sodium alginate, sodium ferric ethylenediaminetetraacetate, and casein phosphopeptide is used as a protective agent. After the protective agent is sterilized, it is sprayed into the red yeast fermentation product, stirred evenly, and left for 3-5 hours to obtain a mixture;
[0011] Step 2, drying the mixture at a temperature below 60-70 degrees Celsius to a water content below 8% to obtain a red yeast rice solid fermentation product;
[0012] Step 3, crushing the red yeast rice solid fermentation product, and sieving through a 60-70 mesh sieve to obtain red yeast rice powder;
[0013] Step 4, mixing the red yeast rice powder, sodium carboxymethyl cellulose and microcrystalline cellulose and further ultrafine grinding them until 90% of the particles have a particle size of less than 45 microns to obtain ultrafine mixed powder;
[0014] Step 5: reconstitute and granulate the ultrafine mixed powder using a dry granulator to obtain small particles.
[0015] Preferably, in the above-mentioned method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, the protective agent is a mixed protective agent aqueous solution prepared in a ratio of 10-15g / L sodium alginate, 5-15g / L sodium ferric ethylenediaminetetraacetate, and 5-15g / L casein phosphopeptide, and is sterilized with high-pressure steam at 121°C for 30 minutes and then cooled to below 50°C for use.
[0016] Preferably, in the above-mentioned method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, the step 2 is specifically: drying the red yeast rice fermentation product in an oven at a temperature below 70° C. to obtain a solid fermentation product with a water content of less than 8%.
[0017] Preferably, in the above method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, the preparation method of the red yeast rice fermentation product in step 1 is as follows:
[0018] Step 01: Prepare slant culture medium: weigh 30-45 g / L soluble starch, 1.5-4.5 g / L sodium nitrate, 1.5-6 g / L potassium dihydrogen phosphate, 150-180 g / L soybean hydrolyzate, 0.15-0.7 g / L magnesium sulfate, 3-8 g / L glucose, 2-10 g / L peptone and 15-25 g / L agar, with the balance being water. Mix the raw materials and boil them to dissolve, then dispense them into test tubes or eggplant bottles, add stoppers and bandages, sterilize them with high pressure steam at 121 degrees Celsius for 30 minutes, and then cool to about 60 degrees Celsius and place them into a slant to obtain a slant culture medium.
[0019] Step 02: Prepare the production strain: inoculate the Monascus strain into a slant culture medium and cultivate it at 30°C for 3 to 5 days to obtain the production strain;
[0020] Step 03: Prepare fermentation medium: brown rice is selected as raw material, washed with water and then soaked in clean water for 5-12 hours, drained and placed on a plate, steamed and cooled in a rice steamer, and brown rice is obtained for use, and then 30-40g / L of soybean powder, 10-20g / L of yeast powder, 50-150g / L of glucose, 5-6g / L of ammonium sulfate, 0.25-0.3g / L of potassium chloride and 0.025-0.03g / L of manganese sulfate are added, and the balance is water, and the pH value is adjusted to 6-7, and the supplementary nutrient solution is obtained after mixing evenly, and finally the supplementary nutrient solution is added to the brown rice according to the ratio of brown rice: supplementary nutrient solution = 1: (0.4-0.7), and the supplementary nutrient solution is dispersed and stirred evenly. After the supplementary nutrient solution is fully absorbed by the brown rice, it is divided into high-temperature resistant plastic culture bottles or glass triangular bottles, and sterilized with high-temperature steam at 121 degrees Celsius for 30 minutes, and the fermentation medium is obtained after cooling;
[0021] Step 04 solid-state fermentation: inoculate the production strain described in step 2 into the fermentation medium described in step 3, and ferment at 20-35° C. for 40 days to obtain red yeast rice fermentation product.
[0022] Preferably, in the above method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, the Monascus species in step 02 is a Monascus species that can produce monacolin K, which is one of Monascus purpurogenum, Monascus tricholoma or Monascus purpurogenum.
[0023] The beneficial effect of the present invention is that in the method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, relative to the technical scheme of the background technology "a method for controlling the ring-opening ratio of monacolin K in functional red yeast rice", additives are added during the fermentation process. After the functional red yeast rice fermentation is completed, sodium alginate, sodium ferric ethylenediaminetetraacetic acid, casein phosphopeptide and red yeast rice are fully stirred, and the added substances form a protective system that is more conducive to the conversion of closed-loop monacolin K to open-loop monacolin K through chelation and coating, etc., which greatly improves the thermal stability of open-loop monacolin K, and greatly reduces the ratio of monacolin open-loop to closed-loop conversion in the subsequent drying process. At the same time, since the protective agent is added after sterilization and cooling after the red yeast rice fermentation is completed, the risk of harmful substances produced by contamination of the red yeast rice fermentation by miscellaneous bacteria is avoided.
[0024] Sodium carboxymethyl cellulose, microcrystalline cellulose, and crushed and sieved red yeast rice powder are mixed and further ultra-finely ground to a particle size of 90% less than 45 microns. In this process, the functional red yeast rice and the added substances are crushed into very fine particles, so that various substances are fully and evenly mixed, creating conditions for subsequent granulation and reconstruction. The ultra-fine mixed powder obtained after ultra-fine grinding is made into small particles by a dry granulator. During the granulation process, the air between the particles overflows, and some particles are broken to form new surface points and bonding points. Finally, the functional red yeast rice powder and other added materials complete the particle reconstruction together, forming a system that is beneficial to protecting the ring-opening stability of monacolin in red yeast rice.
[0025] Through the technology of the present application, while improving the ring-opening rate and stability of monacolin in red yeast rice, the total monacolin K content is also relatively stable. DETAILED DESCRIPTION
[0026] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.
[0027] The method for preparing the fermented red yeast rice used in each embodiment of the present invention comprises the following steps:
[0028] Step 01: Prepare slant culture medium: weigh 30-45 g / L soluble starch, 1.5-4.5 g / L sodium nitrate, 1.5-6 g / L potassium dihydrogen phosphate, 150-180 g / L soybean hydrolyzate, 0.15-0.7 g / L magnesium sulfate, 3-8 g / L glucose, 2-10 g / L peptone and 15-25 g / L agar, with the balance being water. Mix the raw materials and boil them to dissolve, then dispense them into test tubes or eggplant bottles, add stoppers and bandages, sterilize them with high pressure steam at 121 degrees Celsius for 30 minutes, and then cool to about 60 degrees Celsius and place them into a slant to obtain a slant culture medium.
[0029] Step 02: preparing the production strain: using a strain of Monascus sp., such as Monascus Purpureus, Monascus pilosus, Monascus pupureus Went, etc., which can be used to produce functional red yeast rice as the fermentation strain, inoculating the Monascus strain into a slant culture medium, and cultivating it at 30° C. for 3 to 5 days to obtain the production strain;
[0030] Step 03: Prepare fermentation medium: first, select high mountain pollution-free brown rice as the main raw material, wash it with water and then soak it in clean water for 5-12 hours, drain it and put it on a plate, steam it with a rice steamer and cool it, and then the brown rice is ready for use. Then, add 30-40g / L of soybean powder, 10-20g / L of yeast powder, 50-150g / L of glucose, 5-6g / L of ammonium sulfate, 0.25-0.3g / L of potassium chloride and 0.025-0.03g / L of manganese sulfate, and the balance is water. Adjust the pH value to 6-7, mix well and obtain supplementary nutrient solution for use. Finally, add the supplementary nutrient solution to the brown rice at a ratio of brown rice: supplementary nutrient solution = 1: (0.4-0.7), disperse and stir evenly, and after the nutrient solution is fully absorbed by the brown rice, divide it into high-temperature resistant plastic culture bottles or glass triangular bottles, sterilize it with high-temperature steam at 121 degrees Celsius for 30 minutes, and obtain fermentation medium after cooling.
[0031] Step 04: Solid-state fermentation: The production strain described in (3) is inoculated into the fermentation medium described in (4), and fermented at 20-35° C. for 40 days to obtain red yeast rice fermentation product.
[0032] Example 1
[0033] A method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice comprises the following steps:
[0034] Step 1, prepare a mixed protective agent aqueous solution according to the ratio of 12g / L sodium alginate, 15g / L sodium ferric ethylenediaminetetraacetate, and 15g / L casein phosphopeptide, heat and boil for 10 minutes, and then cool to below 50°C for use. After the functional red yeast fermentation is completed, add 300ml of the prepared mixed protective agent per kilogram of the red yeast fermentation product (the red yeast fermentation product used in this embodiment is prepared by the preparation method of the red yeast fermentation product mentioned above), stir evenly, and leave for 5 hours to obtain a mixture;
[0035] Step 2, drying the mixture to a water content of less than 8% at 60-70°C to obtain a solid fermentation product;
[0036] Step 3, crushing the solid fermentation product, and sieving it through a 60-70 mesh sieve to obtain red yeast rice powder A;
[0037] Step 4, 6 parts of red yeast rice powder A, 2 parts of sodium carboxymethyl cellulose and 2 parts of microcrystalline cellulose are mixed and further ultrafinely ground until more than 90% of the particles have a particle size of less than 45 microns to obtain ultrafine mixed powder A;
[0038] Step 5: Reconstruct and granulate the ultrafine mixed powder A using a dry granulator to prepare red yeast rice small particles A.
[0039] The red yeast rice powder A is prepared into red yeast rice small particles C by a dry granulator without adding any auxiliary materials.
[0040] Comparative Example 1
[0041] A method for preparing functional red yeast rice comprises the following steps:
[0042] Step 1, preparing red yeast rice fermentation product according to the preparation method of red yeast rice fermentation product;
[0043] Step 2, drying the red yeast fermentation product in an oven at a temperature below 70° C. to obtain a solid fermentation product with a water content below 8%;
[0044] Step 3, crushing the solid fermentation product, and sieving it through a 60-70 mesh sieve to obtain red yeast rice powder B;
[0045] Step 4, the red yeast rice powder B is ultrafinely ground until 90% of the particles have a diameter of less than 45 μm, to obtain ultrafine mixed powder B;
[0046] Step 5: Use a dry granulator to make the ultrafine mixed powder B into red yeast rice small particles B.
[0047] The average ratios of monacolin K ring opening in the red yeast rice powders obtained in Example 1 and Comparative Example 1 (determined by HPLC) are: red yeast rice powder A 76%; red yeast rice powder B 67%;
[0048] The average ratios of monacolin K ring opening in the red yeast rice granules obtained in Example 1 and Comparative Example 1 (determined by HPLC) were: red yeast rice granules A 76.3%, red yeast rice granules B 67.1%, and red yeast rice granules C 76.2%.
[0049] The average ratios of monacolin K ring-opening in the red yeast rice powder and red yeast rice granules obtained in Example 1 and Comparative Example 1 after one year (determined by HPLC) were: red yeast rice powder A 65.4%; red yeast rice powder B 53.2%; red yeast rice granules A 74.7%; red yeast rice granules B 54.3%; and red yeast rice granules C 67.2%.
[0050] Example 2
[0051] A method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice comprises the following steps:
[0052] Step 1: Prepare a mixed protective agent aqueous solution according to the ratio of 10-15 g / L sodium alginate, 5-15 g / L sodium ferric ethylenediaminetetraacetate, and 5-15 g / L casein phosphopeptide, heat and boil for 10 minutes, then cool to below 50°C for use. Add 300 ml of the prepared mixed protective agent per kilogram of the red yeast fermentation product obtained after the functional red yeast fermentation (the red yeast fermentation product used in this embodiment is prepared by the preparation method of the red yeast fermentation product mentioned above), stir evenly, and leave for 5 hours to obtain a mixture;
[0053] Step 2, drying the mixture in an oven at 60-70° C. to a water content of less than 8% to obtain a solid fermentation product;
[0054] Step 3, crushing the solid fermentation product, and sieving it through a 60-70 mesh sieve to obtain red yeast rice powder;
[0055] Step 4, 6 parts of red yeast rice, 3 parts of sodium carboxymethyl cellulose and 3 parts of microcrystalline cellulose are mixed and then further ultrafinely ground until more than 90% of the particles have a particle size of less than 45 microns to obtain a mixed powder;
[0056] Step 5: The mixed powder is made into small particles using a dry granulator.
[0057] Comparative performance testing
[0058] According to the method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice in Example 2, the effects of protective agents with different ratios on the ring-opening ratio of monacolin in the obtained red yeast rice powder were tested, and the test results are shown in Table 1.
[0059] Table 1
[0060]
[0061] From the test results in Table 1, it can be seen that the addition of sodium alginate, sodium ferric ethylenediaminetetraacetate, and casein phosphopeptide in the method of the present invention forms a protective system that is more conducive to the conversion of closed-loop statins to open-loop statins, greatly improving the thermal stability of open-loop statins, and greatly reducing the proportion of monacolin open-loop to closed-loop conversion in the subsequent drying process. However, the addition of sodium alginate greater than 15g / L or less than 10g / L, sodium ferric ethylenediaminetetraacetate, and casein phosphopeptide greater than 15g / L or less than 5g / L has no significant effect.
[0062] Example 3
[0063] A method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice comprises the following steps:
[0064] Step 1, prepare a mixed protective agent aqueous solution according to the ratio of 12g / L sodium alginate, 15g / L sodium ferric ethylenediaminetetraacetate, and 15g / L casein phosphopeptide, heat and boil for 10 minutes, and then cool to below 50°C for use. After the functional red yeast fermentation is completed, add 300ml of the prepared mixed protective agent per kilogram of the red yeast fermentation product (the red yeast fermentation product used in this embodiment is prepared by the preparation method of the red yeast fermentation product mentioned above), stir evenly, and leave for 5 hours to obtain a mixture;
[0065] Step 2, drying the mixture at 60-70° C. to a water content of less than 8% to obtain a solid fermentation product;
[0066] Step 3, crushing the solid fermentation product, and sieving it through a 60-70 mesh sieve to obtain red yeast rice powder;
[0067] Step 4, mixing sodium carboxymethyl cellulose, microcrystalline cellulose and the red yeast rice powder, and further ultrafine grinding until more than 90% of the particles have a particle size of less than 45 microns to obtain an ultrafine mixed powder;
[0068] Step 5: The ultrafine mixed powder is made into small particles using a dry granulator.
[0069] Comparative performance testing
[0070] According to the method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice of Example 3, the effects of different added amounts of sodium carboxymethyl cellulose and microcrystalline cellulose on the ring-opening rate of the obtained monacolin K after one year were detected by particle reconstruction granulation. The test results are shown in Table 2.
[0071] Table 2
[0072]
[0073] It can be seen from the test results in Table 2 that in the method of the present invention for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, sodium carboxymethyl cellulose and microcrystalline cellulose are added, and a system that is beneficial to protecting the ring-opening stability of monacolin in red yeast rice is formed through particle reconstruction granulation. One year later, the product to which sodium carboxymethyl cellulose and microcrystalline cellulose are added and granulated through particle reconstruction has significantly better stability of the ring-opening ratio of monacolin K than the product simply granulated through particle reconstruction.
[0074] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice, characterized in that: The steps include: Step 1: After the functional red yeast fermentation is completed, a red yeast fermentation product is obtained, and an aqueous solution prepared by mixing sodium alginate, sodium ferric ethylenediaminetetraacetate, and casein phosphopeptide is used as a protective agent. After the protective agent is sterilized, it is sprayed into the red yeast fermentation product, stirred evenly, and left for 3-5 hours to obtain a mixture; Step 2, drying the mixture at a temperature below 60-70 degrees Celsius to a water content below 8% to obtain a red yeast rice solid fermentation product; Step 3, crushing the red yeast rice solid fermentation product, and sieving through a 60-70 mesh sieve to obtain red yeast rice powder; Step 4, mixing the red yeast rice powder, sodium carboxymethyl cellulose and microcrystalline cellulose and further ultrafine grinding them until 90% of the particles have a particle size of less than 45 microns to obtain ultrafine mixed powder; Step 5, reconstructing and granulating the ultrafine mixed powder using a dry granulator to obtain small particles; The protective agent is a mixed protective agent aqueous solution prepared according to the ratio of 10-15g / L sodium alginate, 5-15g / L sodium ferric ethylenediaminetetraacetate, and 5-15g / L casein phosphopeptide, which is heated to boil for 10 minutes and then cooled to below 50°C for standby use.
2. The method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice according to claim 1, characterized in that: In the step 4, the mass ratio of red yeast rice powder, sodium carboxymethyl cellulose and microcrystalline cellulose is 6:1-3:1-3.
3. The method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice according to claim 1, characterized in that: The step 2 specifically includes: drying the red yeast fermentation product in an oven at a temperature below 70° C. to obtain a solid fermentation product with a water content below 8%.
4. The method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice according to claim 1, characterized in that: The preparation method of the red yeast rice fermentation product in step 1 is as follows: Step 01: Prepare slant culture medium: weigh 30-45 g / L soluble starch, 1.5-4.5 g / L sodium nitrate, 1.5-6 g / L potassium dihydrogen phosphate, 150-180 g / L soybean hydrolyzate, 0.15-0.7 g / L magnesium sulfate, 3-8 g / L glucose, 2-10 g / L peptone and 15-25 g / L agar, with the balance being water. Mix the raw materials and boil them to dissolve, then dispense them into test tubes or eggplant bottles, add stoppers and bandages, sterilize them with high pressure steam at 121 degrees Celsius for 30 minutes, and then cool to 60 degrees Celsius and place them into a slant to obtain the slant culture medium. Step 02: Prepare the production strain: inoculate the Monascus strain into a slant culture medium and cultivate it at 30°C for 3 to 5 days to obtain the production strain; Step 03: Prepare fermentation medium: Use brown rice as raw material, wash it with water and then soak it in clean water for 5-12 hours, drain it and put it on a plate, steam it in a rice steamer and cool it, and then you can get brown rice for use, then add 30-40g / L of soybean powder, 10-20g / L of yeast powder, 50-150g / L of glucose, 5-6g / L of ammonium sulfate, 0.25-0.3g / L of potassium chloride and 0.025-0.03g / L of manganese sulfate, and the balance is water, adjust the pH value to 6-7, mix well to get supplementary nutrient solution for use, finally add the supplementary nutrient solution to the brown rice at a ratio of brown rice: supplementary nutrient solution = 1: (0.4-0.7), disperse and stir evenly, after the supplementary nutrient solution is fully absorbed by the brown rice, divide it into high temperature resistant plastic culture bottles or glass triangular bottles, sterilize it with high temperature steam at 121 degrees Celsius for 30 minutes, and get fermentation medium after cooling; Step 04 solid-state fermentation: inoculate the production strain described in step 2 into the fermentation medium described in step 3, and ferment at 20-35° C. for 40 days to obtain red yeast rice fermentation product.
5. The method for improving the ring-opening ratio and stability of monacolin K in functional red yeast rice according to claim 4, characterized in that: The Monascus species in step 02 is a Monascus species that can produce monacolin K, which is one of Monascus purpurogenus, Monascus pubescens or Monascus purpurogenus.