Cordyceps militaris cultivation method with high yield and low total ash content

Abstract

This invention relates to a cultivation method for high-yield, low-total-ash Cordyceps militaris. The method involves using rice or wheat with 10-50% residual cortex as a solid substrate. Water is added, and the substrate is then subjected to sterilization treatment under the following conditions: 0.2-0.3% α-amylase is added to the solid substrate, and the substrate is kept at 65-90℃ for 0.5-1 hour; then, the temperature is lowered to 60-70℃, and 0.05-0.1% β-amylase is added, and the substrate is kept at 0.5-1 hour; then, the temperature is lowered to 40-60℃, and 0.05-0.15% pullulanase is added, and the substrate is kept at 0.5-1 hour; finally, the substrate is autoclaved at 121℃ for 0.5-1 hour; and finally, the substrate is cooled, inoculated, cultured, and harvested. This technical solution uses rice or wheat with 10-50% residual husk as a solid matrix raw material. By combining a specific sequence of steaming and sterilization processes with enzyme treatment, it can achieve the unexpected technical effect of increasing yield and reducing total ash content. This results in a 30-60% reduction in total ash content in Cordyceps militaris fruiting bodies and a further 10-30% increase in Cordyceps militaris yield or bioconversion rate. This will help to further promote the high-quality development of the Cordyceps militaris industry and the widespread application of Cordyceps militaris deep processing.

Description

Technical Field

[0001] This invention relates to the field of edible and medicinal fungi cultivation, specifically a cultivation method for Cordyceps militaris with high yield and low total ash content. Background Technology

[0002] Cordyceps militaris ( Cordyceps militaris(L.)Fr. Cordyceps sinensis, also known as North Cordyceps, is a commonly used edible and medicinal fungus. It belongs to the phylum Ascomycota, class Sordariomycetes, class Hypocreales, family Cordycipitaceae, and genus Cordyceps. Cordyceps It belongs to the same genus of fungi as Cordyceps sinensis. It is rich in nutrients and has the effects of protecting the lungs and kidneys and strengthening the body. It has gradually become an ideal substitute for Cordyceps sinensis.

[0003] Total ash refers to the mineral elements remaining after a sample is burned. In the food industry, if the total ash content exceeds the standard limit, it usually indicates that raw materials or food additives that do not meet hygiene standards were used in food production, or that the food was contaminated during processing, storage, and transportation. Beyond these general situations, the total ash content of food raw materials affects their intrinsic quality and performance, such as the color, gloss, water absorption (shelf life), and taste of Cordyceps militaris products, thus impacting the widespread application and development of Cordyceps militaris in the food processing industry. With China's sustained high-speed economic development over the past 20 years, the domestic health industry has experienced explosive growth, and the production capacity and market demand for Cordyceps militaris have also increased rapidly. As the country comprehensively promotes socialist modernization, the Cordyceps militaris and related product industry will inevitably tend towards high-quality development. On August 26, 2019, the Standardization Administration of China announced industry standards such as GH / T 1240-2019 "Dried Cordyceps militaris," which sets the limit for the total ash content in Cordyceps militaris fruiting bodies at ≤10%, thus unifying technical requirements across the industry for the first time. Currently, the total ash content in Cordyceps militaris fruiting bodies on the market and in publicly available reports generally remains at a level of 6-10%, which meets the standard limit. Furthermore, since total ash is not a crucial indicator for grading Cordyceps militaris, there is currently no research or report on how to further reduce the total ash content in Cordyceps militaris fruiting bodies within this technical field.

[0004] On the other hand, existing technology reports that wheat or rice seed coats contain a large amount of minerals and cellulose, and are the part of wheat grains with the highest ash content. Therefore, removing the seed coat can predictably reduce the total ash content in the substrate raw material, and may consequently reduce or to some extent reduce the total ash content in Cordyceps militaris fruiting bodies. However, removing the seed coat from rice or wheat will lead to a significant or severe reduction in the bioconversion rate or yield of Cordyceps militaris (see instruction manual). Figure 1Clearly, dehulling rice or wheat cannot achieve the dual benefits of "low total ash and increased yield" without affecting output. For production enterprises that need to control raw material costs and prioritize "stable and high yields," since Cordyceps militaris already meets industry standards, further dehulling rice or wheat would be a counterproductive measure. Real-world experience and established industry practices dictate that dehulling rice or wheat is not advisable, which is the main reason why there are no reports on reducing the total ash content in Cordyceps militaris fruiting bodies in this technical field. Meanwhile, starch hydrolases refer to a class of enzymes that catalyze the hydrolysis of starch. They possess substrate specificity and can hydrolyze substrates into various reducing and non-reducing monosaccharides and small amounts of polysaccharides. Aside from the secondary use of Cordyceps militaris culture medium or its application in health food processing, amylase has rarely been used in Cordyceps militaris cultivation. Even when it is used, its application is limited to the foreseeable absorption of nutrients by Cordyceps militaris mycelia, potentially increasing yield and total ash content to some extent. It cannot foresee the technical effect of "low total ash and increased yield," nor can it provide technical insights into the effects of specific combinations of amylases (α-amylase, β-amylase, and pullulanase) and their specific or closely related process sequences and parameters to improve the physical properties of Cordyceps militaris culture medium. Therefore, even if those skilled in the art are motivated to use hulled rice or wheat in combination with amylase for Cordyceps militaris cultivation, they cannot foresee or easily experiment to achieve the dual technical effect of "low total ash and increased yield."

[0005] To overcome the obstacles or prejudices in the application of hulled rice or wheat in Cordyceps militaris cultivation, to further improve the quality of Cordyceps militaris, and to solve the technical problem of the inability to achieve both low total ash content and increased yield, this technical solution provides a cultivation method for high-yield, low-total-ash Cordyceps militaris. It uses rice or wheat with 10-50% hull residue as a solid culture medium. After adding water, the medium undergoes a specific steaming and sterilization process: 0.2-0.3% α-amylase is added to the solid substrate, and the medium is kept at 65-90℃ for 0.5-1 hour; then, the temperature is lowered to 60-70℃, and 0.05-0.1% β-amylase is added, and the medium is kept at 0.5-1 hour; finally, the temperature is lowered to 40-60℃, and 0.05-0.15% pullulanase is added, and the medium is kept at 0.5-1 hour; then, the medium is autoclaved at 121℃ for 0.5-1 hour; finally, the medium is cooled, inoculated, cultured, and harvested. This technical solution is simple and easy to implement, overcoming the application obstacles of peeled rice or wheat. By combining enzyme treatment with a specific sequence of steaming and sterilization processes, it can achieve the unexpected technical effect of increasing yield and reducing total ash content. It can reduce the total ash content in Cordyceps militaris fruiting bodies by 30-60%, and compared with the use of unpeeled raw materials, the yield or bioconversion rate of Cordyceps militaris can be further increased by 10-30%. Summary of the Invention

[0006] To further improve the quality of Cordyceps militaris and solve the technical problem of simultaneously achieving low total ash content and high yield, this technical solution provides a cultivation method for high-yield, low-total-ash Cordyceps militaris. It uses rice or wheat with 10-50% residual cortex as a solid culture medium. After adding water, the medium undergoes a specific steaming and sterilization process: 0.2-0.3% α-amylase is added to the solid substrate, and the medium is incubated at 65-90℃ for 0.5-1 hour; then, the temperature is lowered to 60-70℃, and 0.05-0.1% β-amylase is added, followed by incubation for 0.5-1 hour; finally, the temperature is lowered to 40-60℃, and 0.05-0.15% pullulanase is added, followed by incubation for 0.5-1 hour; and then, the medium is autoclaved at 121℃ for 0.5-1 hour. Finally, the medium is cooled, inoculated, cultured, and harvested. The specific steps of this technical solution are as follows:

[0007] 1. Peeling process: Use peeling equipment to remove the husk from rice or wheat, obtaining grains with 10-50% husk residue, which can be used as a solid substrate for cultivating Cordyceps militaris.

[0008] 2. Preparation of culture medium: Weigh the aforementioned solid matrix, weigh α-amylase at 0.2-0.3% of the solid matrix, add 1.2-1.5 times the amount of water to the solid matrix, stir well, and the culture medium is prepared.

[0009] 3. Sterilization by boiling: The above culture medium is sterilized by boiling in a specific order, i.e., incubating at 65-90℃ for 0.5-1 hour; cooling to 60-70℃, adding 0.05-0.1% β-amylase by weight of solids and incubating for 0.5-1 hour; cooling to 40-60℃, adding 0.05-0.15% pullulanase by weight of solids and incubating for 0.5-1 hour; and then autoclaving at 121℃ for 0.5-1 hour.

[0010] 4. Cooling and inoculation: Cool the culture medium after the above-mentioned steaming and sterilization treatment, and inoculate it with Cordyceps militaris inoculum;

[0011] 5. Culture medium and harvesting: Place the inoculated culture medium in the mycelium growth room and incubate in the dark at 16-18℃ for 3-5 days. After the surface is covered with mycelium, transfer it to the cultivation room and cultivate under light at 18-20℃ and 400-600 Lux. Harvesting can begin on the 50th day of cultivation.

[0012] Compared with existing technologies, this technical solution has the following main advantages:

[0013] 1. Overcoming the industry's common perception that "removing the husk from rice or wheat will reduce yield or bioconversion rate", and unexpectedly achieving the dual technical effect of "reducing total ash content and increasing yield";

[0014] 2. Significant technical effects have been achieved, including a 30-60% reduction in total ash content in Cordyceps militaris fruiting bodies, and a 10-30% increase in yield or bioconversion rate compared to using unpeeled raw materials.

[0015] 3. The process is simple and easy to implement, which is conducive to its widespread promotion and can further promote the high-quality development of Cordyceps militaris and its extensive application in deep processing and other fields. Attached Figure Description

[0016] Figure 1 The effects of rice or wheat with different degrees of peeling on the yield and total ash content of Cordyceps militaris and the technical effects of preferred embodiments.

[0017] The specific implementation method is as follows:

[0018] Example 1

[0019] 1. Peeling process: Peeling equipment is used to remove the husk from the rice grains, resulting in grains with 20% husk residue, which are used as a solid substrate for cultivating Cordyceps militaris.

[0020] 2. Preparation of culture medium: Weigh the aforementioned solid matrix, weigh α-amylase at 0.2% of the solid matrix, add 1.5 times the amount of water to the solid matrix, stir well, and the culture medium is prepared.

[0021] 3. Sterilization treatment: The above culture medium was sterilized by steaming in a specific order, namely, incubating at 90℃ for 1 hour; cooling to 60℃ and adding 0.05% β-amylase (by weight of solids) and incubating for 0.5 hours; cooling to 40℃ and adding 0.15% pullulanase (by weight of solids) and incubating for 1 hour; and then autoclaving at 121℃ for 0.5 hours.

[0022] 4) Cooling and inoculation: Cool the culture medium after the above-mentioned steaming and sterilization treatment, and inoculate it with Cordyceps militaris spawn;

[0023] 5) Culture medium and harvesting: Place the inoculated culture medium in the mycelium growth room and incubate in the dark at 16-18℃ for 3-5 days. After the surface is covered with mycelium, transfer it to the cultivation room and cultivate under light at 18-20℃ and 400-600 Lux. Harvesting begins on the 50th day of cultivation.

[0024] Example 2

[0025] 1) Peeling treatment: Use peeling equipment to remove the husk from wheat grains, obtaining grains with 20% husk residue, which are used as a solid substrate for cultivating Cordyceps militaris.

[0026] 2) Preparation of culture medium: Weigh the aforementioned solid matrix, weigh α-amylase at 0.2% of the solid matrix, add 1.5 times the amount of water to the solid matrix, stir well, and the culture medium is obtained;

[0027] 3) Sterilization treatment: The above culture medium was sterilized by steaming in a specific order, namely, incubating at 65℃ for 0.5 hours; cooling to 60℃, adding 0.05% β-amylase by weight of solids and incubating for 0.5 hours; cooling to 60℃, adding 0.05% pullulanase by weight of solids and incubating for 0.5 hours; and then autoclaving at 121℃ for 1 hour.

[0028] 4) Cooling and inoculation: Cool the culture medium after the above-mentioned steaming and sterilization treatment, and inoculate it with Cordyceps militaris spawn;

[0029] 5) Culture medium and harvesting: Place the inoculated culture medium in the mycelium growth room and incubate in the dark at 16-18℃ for 3-5 days. After the surface is covered with mycelium, transfer it to the cultivation room and cultivate under light at 18-20℃ and 400-600 Lux. Harvesting begins on the 50th day of cultivation.

[0030] Figure 1 The effects of different degrees of rice or wheat peeling on the yield and total ash content of Cordyceps militaris, and the technical effects of preferred embodiments.

[0031] Note: The bioconversion rate in the figure is calculated as the dry weight of dried fruiting bodies / dry weight of the dry basis used * 100; the method for determining the total ash content of Cordyceps militaris fruiting bodies is based on the national food safety standard GB5009.4-2016 "Determination of Ash Content in Food".

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the manner adopted by the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cultivation method for Cordyceps militaris with high yield and low total ash content, characterized in that, Using rice or wheat with 10-50% residual bran as a solid culture medium, water is added, and the medium is sterilized by steaming in a specific sequence: first, 0.2-0.3% α-amylase of the solid matrix is ​​added and incubated at 65-90℃ for 0.5-1 hour; then, the temperature is lowered to 60-70℃, 0.05-0.1% β-amylase of the solid matrix is ​​added and incubated for 0.5-1 hour; finally, the temperature is lowered to 40-60℃, 0.05-0.15% pullulanase of the solid matrix is ​​added and incubated for 0.5-1 hour; and then, the temperature is raised to 121℃ for autoclaving for 0.5-1 hour. Finally, the medium is cooled, inoculated, cultured, and harvested. The specific steps of the cultivation method for Cordyceps militaris with high yield and low total ash content include: 1) Peeling treatment: Use peeling equipment to remove the husk from rice or wheat, obtaining grains with 10-50% husk residue, which can be used as a solid substrate for cultivating Cordyceps militaris. 2) Preparation of culture medium: Weigh the aforementioned solid matrix, weigh α-amylase at 0.2-0.3% of the solid matrix, add 1.2-1.5 times the amount of water of the solid matrix, stir evenly, and the culture medium is prepared; 3) Sterilization treatment: The above culture medium is sterilized by steaming in a specific order, namely, incubating at 65-90℃ for 0.5-1 hour; cooling to 60-70℃, adding 0.05-0.1% β-amylase by weight of solids and incubating for 0.5-1 hour; cooling to 40-60℃, adding 0.05-0.15% pullulanase by weight of solids and incubating for 0.5-1 hour; and autoclaving at 121℃ for 0.5-1 hour. 4) Cooling and inoculation: Cool the culture medium after the above-mentioned steaming and sterilization treatment, and inoculate it with Cordyceps militaris spawn; 5) Culture medium and harvesting: Place the inoculated culture medium in the mycelium growth room and incubate in the dark at 16-18℃ for 3-5 days. After the surface is covered with mycelium, transfer it to the cultivation room and cultivate under light at 18-20℃ and 400-600 Lux. Harvesting begins on the 50th day of cultivation.

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