Yeast extract rich in bases and base derivatives and method for producing the same

Abstract

Provided are a yeast extract rich in bases and base derivatives and a method for producing the same. The provided yeast extract rich in bases and base derivatives contains 20,000 to 40,000 mg / kg of bases and base derivatives. The provided yeast extract is rich in bases and base derivatives, and bases and base derivatives are more easily absorbed by microorganisms than nucleotides, so that the provided product has a high ability to promote the growth of microorganisms.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological products, and specifically relates to yeast extract rich in bases and base derivatives and a method for producing the same.

Background Art

[0002] Yeast extract is a powdery, paste-like or liquid product obtained by using fresh yeast raw materials, inducing many enzyme systems of yeast itself by utilizing modern biotechnology or changing the culture environment, decomposing intracellular proteins and nucleic acid substances under appropriate conditions by using some exogenous enzymes, and further undergoing some purification processes. It is rich in proteins, amino acids, peptides, nucleotides, vitamin B, and trace elements. Its main roles are to supplement the nitrogen source and provide various vitamins, amino acids, and growth factors necessary for the growth of microorganisms. It is widely used in the fermentation medium industry and is a medium raw material with high growth-promoting ability.

[0003] Bases (Nucleobase) and base derivatives (Nucleobase derivatives) are different from nucleotides. They are products obtained by further decomposing nucleotides and are the constituent units of yeast nucleic acids. They can be obtained by the decomposition of yeast nucleic acids in the self-decomposition process of yeast. Base derivatives are products obtained by further decomposing bases. In the self-decomposition process of yeast, the decomposing enzymes of yeast nucleic acids can be activated to decompose yeast nucleic acids into bases and base derivatives.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The bases and base derivatives richly contained in yeast extract can provide special growth factors for microorganisms and significantly promote the growth of microorganisms. In addition, it can promote the metabolism of microorganisms to produce some pharmaceutical intermediates, such as adenosine, inosine, etc.

[0005] In conventional yeast extracts, the breakdown of yeast nucleic acids is limited to the nucleotide level, and does not extend to bases and base derivatives. As a result, conventional yeast extracts have a very low content of bases and base derivatives, and cannot meet the efficient production needs of microbial fermentation companies.

[0006] This invention provides a yeast extract rich in bases and base derivatives in order to solve the technical problem of the low content of bases and base derivatives in conventional yeast extracts.

[0007] The yeast extract provided by this invention contains more than 20,000 mg / kg of bases and base derivatives. [Means for solving the problem]

[0008] In a first embodiment, the present invention provides a yeast extract rich in bases and base derivatives, wherein the yeast extract contains 20,000 to 40,000 mg / kg of bases and base derivatives.

[0009] Preferably, the yeast extract contains 22,000 to 39,000 mg / kg of bases and base derivatives. Preferably, the base and base derivative are selected from one or more combinations of adenine, guanine, uracil, cytosine, xanthine, and hypoxanthine. Preferably, the yeast extract contains 2000 to 5000 mg / kg of adenine. And / or, preferably, the yeast extract contains 3000 to 6000 mg / kg of guanine. And / or, preferably, the yeast extract contains 4000 to 7000 mg / kg of uracil. And / or, preferably, the yeast extract contains 1500 to 5000 mg / kg of cytosine. And / or, preferably, the yeast extract contains 8,000 to 11,000 mg / kg of xanthine. And / or, preferably, the yeast extract contains 2000 to 5000 mg / kg of hypoxanthine.

[0010] Preferably, the yeast extract contains 10-12% total nitrogen by mass percentage, and preferably, the yeast extract contains 10.5-11.8% total nitrogen by mass percentage. Preferably, the yeast extract contains 3.5 to 5.5% amino acid nitrogen by mass percentage, and preferably, the yeast extract contains 4 to 5% amino acid nitrogen by mass percentage.

[0011] In a second embodiment, the present invention provides a method for producing the yeast extract, the production method being: The process includes heating yeast milk to 40-60°C, adjusting the pH to 5.0-6.0, adding an enzyme preparation at a mass percentage of 0.1-1% based on the dry weight of the yeast milk, adding a precursor at a mass percentage of 1-5% based on the dry weight of the yeast milk, and allowing it to autodegrade for 15-24 hours.

[0012] The precursor described in this invention is converted into a base and a base derivative through a self-decomposition process.

[0013] Preferably, the enzyme preparation is one or more combinations of nuclease, adenine deaminase, and guanine deaminase. Preferably, the enzyme preparation is a combination of nuclease, adenine deaminase, and guanine deaminase. Preferably, the mass ratio of the nuclease, adenine deaminase, and guanine deaminase is 2.5 to 5:1:1.

[0014] Preferably, the precursor is one or more of yeast RNA or disodium nucleotides that enhance flavor.

[0015] Preferably, the manufacturing method further includes the steps of inactivating the enzyme after autolysis, separating the solid and liquid, and then extracting and concentrating the liquid to obtain a yeast extract. Preferably, the enzyme is inactivated at 65-75°C. Preferably, the concentration method is vacuum evaporation.

[0016] Preferably, the yeast is selected from one or a combination of two or more of budding yeast, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

[0017] Preferably, the method for preparing the yeast milk is including the steps of inoculating a yeast seed into a medium, culturing for 12 to 24 hours under the conditions of pH 4.0 to 6.0 and temperature 30 to 33°C, and collecting yeast cells to obtain yeast milk.

[0018] Preferably, in the yeast milk, based on the dry matter content, the content of yeast cells is 10 to 15 wt%, and the rest is water.

[0019] Preferably, the inoculation amount is 1 to 5 wt%, Preferably, in the medium, 3 to 10 g of carbon source, 0.5 to 1 g of yeast extract, 2 to 5 g of ammonium sulfate, 1 to 2 g of magnesium sulfate, 0.5 to 1 g of potassium dihydrogen phosphate, and 0.1 to 0. _5 g of zinc sulfate are added per 100 mL of water. Preferably, the carbon source is selected from one or a combination of multiple of sugarcane molasses, sugar beet molasses, or hydrolyzed sugar.

[0020] In a third aspect, the present invention further provides a yeast extract produced by the manufacturing method.

[0021] In a fourth aspect, the present invention further provides the use of the yeast extract or the yeast extract produced by the manufacturing method in food, feed, and medium.

Advantages of the Invention

[0022] Yeast extract is a nutrient-complete organic nitrogen source that provides a nitrogen source for the growth of microorganisms and at the same time provides growth factors such as trace elements and vitamins. Conventional yeast extracts are rich in nucleotides, but the yeast extract provided by the present invention is rich in bases and base derivatives. Since bases and base derivatives are more easily absorbed by microorganisms than nucleotides, the product provided by the present invention has a higher ability to promote the growth of microorganisms and better quality than conventional yeast extracts. The production method provided by the present invention can significantly increase the content of bases and base derivatives in the yeast extract.

Embodiments for Carrying out the Invention

[0023] An object of the present invention is to provide a yeast extract rich in bases and base derivatives. Conventional yeast extracts have a low content of bases and base derivatives, insufficient ability to promote the growth of microorganisms and the production of products by microbial metabolism, and cannot meet the needs of efficient production of microbial fermentation enterprises. The yeast extract provided by the present invention is rich in bases and base derivatives and has a high ability to promote the growth and metabolism of microorganisms. By using the method provided by the present invention, an enzyme preparation and a substrate are added to yeast milk, and conditions such as temperature and pH are controlled to promote the autolysis of yeast and at the same time promote the decomposition of yeast nucleic acid into bases and base derivatives, thereby obtaining a yeast extract rich in bases and base derivatives.

[0024] In the yeast extract provided by the present invention, the content of bases and base derivatives exceeds 20,000 mg / kg. The bases are one or a combination of two or more of adenine, guanine, uracil, and cytosine, and the base derivatives are one or two of hypoxanthine and xanthine.

[0025] The method for producing yeast extract provided by the present invention includes the steps of: decomposing yeast milk with an autolytic enzyme; adding an enzyme preparation to the yeast milk; and allowing it to autodecompose for 15 to 24 hours under conditions of 40 to 60°C and pH 5.0 to 6.0. In preferred embodiments of the present invention, the method further includes the steps of: separating and purifying the product obtained by autodecomposition; preferably, separating the yeast autodecomposition liquid from the solid-liquid and concentrating the liquid to obtain yeast extract; and preferably, obtaining a paste-like yeast extract by vacuum evaporation or a powder-like yeast extract by spray drying. In specific embodiments of the present invention, vacuum evaporation is carried out under conditions of 92 to 95 kPa and 80°C.

[0026] In a specific embodiment provided by the present invention, the method for producing the yeast extract includes the following steps. 1) Preparation of yeast milk, with fermentation conditions of pH 4.0-6.0, culture temperature of 30-33°C, and culture time of 12-24 hours. The fermentation medium composition is 3-10% carbon source, 0.5-1% yeast extract, 2-5% ammonium sulfate, 1-2% magnesium sulfate, 0.5-1% potassium dihydrogen phosphate, and 0.1-0.5% zinc sulfate (all in mass-to-volume ratio w / v). Here, the carbon source is one or more types of sugarcane molasses, beet molasses, or hydrolyzed sugar. After fermentation is complete, the fermentation liquid is centrifuged at 5000-7000 rpm, the supernatant is discarded, pure water is added to the heavy liquid, and then centrifuged again to obtain washed yeast. The yeast is further diluted with pure water to obtain yeast milk with a dry matter content of 10-15%.

[0027] 2) A yeast autolysis process, in which the yeast milk is heated to 40-60°C and maintained at this temperature. The pH is adjusted to 5.0-6.0, an enzyme preparation is added at a rate of 0.1-1% by dry weight of the yeast milk, and a substrate is added at a rate of 1-5% by dry weight of the yeast milk, and autolysis is allowed for 15-24 hours. The enzyme preparation is a nuclease, adenine deaminase, or guanine deaminase, and the substrate is yeast RNA or disodium nucleotide for flavoring.

[0028] 3) Separation and purification, wherein after autolysis of the yeast, an autolysis liquid is obtained, subjected to enzyme inactivation treatment at 65-75°C, and then centrifuged in a centrifuge at 5000-7000 rpm for 5-10 minutes to collect the supernatant, and the supernatant is evaporated under reduced pressure to obtain a yeast extract paste rich in bases and base derivatives (moisture content 30-35%), or a powder is obtained by spray drying (moisture content less than 5%).

[0029] The suppliers of the reagents used in the examples are shown in Table 1 below. [Table 1]

[0030] The budding yeast FX-2 (Saccharomyces cerevisiae FX-2) used in the embodiments of this invention was deposited with the China Typical Culture Depository Center (CCTCC) on August 1, 2016, with deposit number M2016418, and is located at Wuhan University in Wuhan, China. This strain is described in the patent disclosure of Chinese Patent Application Publication No. 108220175.

[0031] The Wickerhamomyces anomalus C1.7 used in the embodiments of this invention was deposited with the China Typical Culture Depositary Center (CCTCC) on December 11, 2017, with deposit number M2017782, at Wuhan University in Wuhan, China. This strain is described in the patent disclosure of Chinese Patent Application Publication No. 110959853.

[0032] The Cyberlindnera fabianii C1.8 used in the embodiments of this invention was deposited with the China Typical Culture Depositary Center (CCTCC) on December 11, 2017, with deposit number M2017780, at Wuhan University in Wuhan, China. This strain is described in the patent disclosure of Chinese Patent Application Publication No. 110959853.

[0033] (Example 1: Yeast extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio to water: 3% sugarcane molasses, 0.8% yeast extract, 2% ammonium sulfate, 1% magnesium sulfate, 0.5% potassium dihydrogen phosphate, and 0.1% zinc sulfate, and the pH was adjusted to 4.5.

[0034] 2. The culture of budding yeast FX-2 was performed with an inoculation of 1% (w / v) of budding yeast FX-2, a culture temperature of 30°C, an aeration rate of 50 L / min, a stirring speed of 300 rpm / min, and cultured for 12 hours.

[0035] 3. The mixture was centrifuged at 5000 rpm for 5 minutes in a centrifuge to collect the heavy liquid. Pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 5000 rpm for 5 minutes. The heavy liquid was collected again, and 10% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0036] 4. The above yeast milk was heated to 50°C, the pH was adjusted to 5.0, 0.1% adenine deaminase was added based on the dry weight of the yeast milk, and 1% disodium nucleotide for flavoring was added as a substrate. The temperature and pH were maintained to prevent changes during autolysis, and autolysis was carried out for 20 hours.

[0037] 5. The temperature of the autolysis solution was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 3.5%.

[0038] (Example 2: Yeast extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio relative to water: 5% sugarcane molasses, 0.5% yeast extract, 4% ammonium sulfate, 1.5% magnesium sulfate, 0.5% potassium dihydrogen phosphate, and 0.3% zinc sulfate, and the pH was adjusted to 5.0.

[0039] 2. Culture of Wickerhamomyces anomalus C1.7 yeast, with an inoculation of 1% (w / v) of Wickerhamomyces anomalus C1.7 yeast, a culture temperature of 30°C, an aeration rate of 50 L / min, a stirring speed of 300 rpm / min, and culture for 20 hours.

[0040] 3. The mixture was centrifuged at 6000 rpm for 5 minutes, the heavy liquid was collected, pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 6000 rpm for 5 minutes, the heavy liquid was collected again, and 12% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0041] 4. The above yeast milk was heated to 40°C, the pH was adjusted to 5.5, 0.25% nuclease and 0.1% guanine deaminase were added based on the dry weight of the yeast milk, and 3% yeast RNA was added as a substrate. The temperature and pH were maintained to prevent changes during autolysis, and the autolysis was carried out for 15 hours.

[0042] 5. The temperature of the autolysis solution was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 3.7%.

[0043] (Example 3: Yeast extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio to water: 10% sugarcane molasses, 1% yeast extract, 5% ammonium sulfate, 2% magnesium sulfate, 0.5% potassium dihydrogen phosphate, and 1% zinc sulfate, and the pH was adjusted to 6.0.

[0044] 2. Culture of Cyberlindnera fabianii C1.8 yeast, with an inoculation of 1% (w / v) of Cyberlindnera fabianii C1.8, culture temperature of 33°C, aeration rate of 50 L / min, stirring speed of 300 rpm / min, and culture for 24 hours.

[0045] 3. The mixture was centrifuged at 6000 rpm for 5 minutes, the heavy liquid was collected, pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 6000 rpm for 5 minutes, the heavy liquid was collected again, and 15% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0046] 4. The above yeast milk was heated to 60°C, the pH was adjusted to 6.0, and 0.5% nuclease, 0.1% adenine deaminase, and 0.1% guanine deaminase were added based on the dry weight of the yeast milk. 3% yeast RNA was added as a substrate, and 2% disodium nucleotide for flavoring was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 24 hours.

[0047] 5. The temperature of the autolysis solution was raised to 70°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 3.0%.

[0048] (Comparative Example 1: Effect of enzymes on the properties of yeast extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio to water: 6% sugarcane molasses, 0.8% yeast extract, 3.5% ammonium sulfate, 1% magnesium sulfate, 0.3% potassium dihydrogen phosphate, and 0.6% zinc sulfate, and the pH was adjusted to 5.5.

[0049] 2. Yeast culture was performed with an inoculation of budding yeast FX-2 at 1% (w / v), a culture temperature of 30°C, an aeration rate of 50 L / min, a stirring speed of 300 rpm / min, and cultured for 20 hours.

[0050] 3. The mixture was centrifuged at 6000 rpm for 5 minutes, the heavy liquid was collected, pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 6000 rpm for 5 minutes, the heavy liquid was collected again, and 13% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0051] 4. The above yeast milk was heated to 55°C, the pH was adjusted to 5.5, and the temperature and pH were maintained to prevent changes during autolysis, allowing it to autolyze for 20 hours.

[0052] 5. The temperature of the autolysis solution was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 4.0%.

[0053] (Comparative Example 2: Effect of enzyme usage on the properties of yeast extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio to water: 10% sugarcane molasses, 1% yeast extract, 5% ammonium sulfate, 2% magnesium sulfate, 0.5% potassium dihydrogen phosphate, and 1% zinc sulfate, and the pH was adjusted to 6.0.

[0054] 2. Culture of Cyberlindnera fabianii C1.8 yeast, with an inoculation of 1% (w / v) of Cyberlindnera fabianii C1.8 yeast, a culture temperature of 33°C, an aeration rate of 50 L / min, a stirring speed of 300 rpm / min, and culture for 24 hours.

[0055] 3. The mixture was centrifuged at 6000 rpm for 5 minutes, the heavy liquid was collected, pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 6000 rpm for 5 minutes, the heavy liquid was collected again, and 15% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0056] 4. The above yeast milk was heated to 60°C, the pH was adjusted to 6.0, and 0.05% nuclease, 0.03% adenine deaminase, and 0.03% guanine deaminase were added on a dry weight basis to the yeast milk. 3% yeast RNA was added as a substrate, and 2% disodium nucleotide for flavoring was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 24 hours.

[0057] 5. The temperature of the autolysis solution was raised to 70°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 3.2%.

[0058] (Comparative Example 3: Effect of Precursor Usage on the Properties of Yeast Extract) It was a yeast extract, and its manufacturing method was as follows: 1. Preparation of yeast culture medium: Using 100 L of pure water, the culture medium was prepared with the following ingredients in mass ratio to water: 3% sugarcane molasses, 0.8% yeast extract, 2% ammonium sulfate, 1% magnesium sulfate, 0.5% potassium dihydrogen phosphate, and 0.1% zinc sulfate, and the pH was adjusted to 4.5.

[0059] 2. The culture of budding yeast FX-2 was performed with an inoculation of 1% (w / v) of budding yeast FX-2, a culture temperature of 30°C, an aeration rate of 50 L / min, a stirring speed of 300 rpm / min, and cultured for 12 hours.

[0060] 3. The mixture was centrifuged at 5000 rpm for 5 minutes, the heavy liquid was collected, pure water was added to the heavy liquid, and after stirring until homogenized, it was centrifuged again at 5000 rpm for 5 minutes, the heavy liquid was collected again, and 10% (w / v) of the dry weight of the yeast cells was added to the pure water.

[0061] 4. The above yeast milk was heated to 50°C, the pH was adjusted to 5.0, 0.5% nuclease, 0.1% adenine deaminase, and 0.1% guanine deaminase were added based on the dry weight of the yeast milk, 0.5% yeast RNA was added as a substrate, and 0.2% disodium nucleotide for flavoring was added as a substrate. The temperature and pH were maintained to prevent changes during autolysis, and autolysis was allowed to proceed for 22 hours.

[0062] 5. The temperature of the autolysis solution was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes. The supernatant was collected and concentrated by reduced-pressure evaporation under conditions of 92-95 kPa and 80°C, and then spray-dried to obtain a powdered product. The moisture content was 3.8%.

[0063] The total nitrogen, amino acid nitrogen, water content, base and base derivative content, and the content of each base and base derivative were measured in the yeast extracts produced in Examples 1-3 and Comparative Examples 1-3. The measurement methods for each physical and chemical indicator are as follows. The results are shown in Tables 2 and 3.

[0064] (1) Measurement of moisture The method described in section 6.2 of the Chinese standard GB / T 23530-2009 was adopted. A specified mass of sample was used, dried at 103°C for 4 hours until it reached a constant weight, and then weighed to calculate the moisture content. The results are shown in Table 2.

[0065] (2) Measurement of total nitrogen The Kjeldahl method according to Chinese standard GB / T 23530-2009, section 6.4, was adopted. A sample (equivalent to 30-440 mg of total nitrogen) was digested by boiling in an environment where 5 g of mixed catalyst a (a mixture of potassium sulfate and copper sulfate pentahydrate in a 97:3 ratio) and 2.5 g of catalyst b (a mixture of powdered selenium and potassium sulfate in a 0.1:100 ratio) were reacted, with 20 mL of concentrated sulfuric acid added. Further distillation was performed, and the ammonia product was absorbed with boric acid. Titration was performed with 0.1 mol / L hydrochloric acid, and the data was read to calculate the total nitrogen content. The results are shown in Table 2.

[0066] (3) Measurement of amino acid nitrogen The method for measuring amino acid nitrogen described in section 6.5 of the Chinese standard GB / T 23530-2009 was adopted. Using a 5g sample, after dilution, the sample was titrated with a 0.5 mol / L sodium hydroxide solution until the pH reached 8.2, and maintained for 1 minute. 10 mL of 36% formaldehyde solution was slowly added to react with the non-dissociated amino groups in the neutral amino acid to produce monohydroxymethyl and dihydroxymethyl derivatives. This reaction was carried out entirely quantitatively. The hydrogen ions released during this reaction were titrated with the aforementioned sodium hydroxide, and the amino acid nitrogen content was calculated from the amount of alkaline solution consumed. The results are shown in Table 2.

[0067] (4) pH measurement The pH measurement method described in 7.2.1 of Chinese Standard GB / T 35536-2017 was adopted. An aqueous solution of the specified mass percentage concentration was prepared, and the pH after sterilization was measured using a glass electrode. The difference between two measurements of the same sample should not exceed 0.04.

[0068] (5) Measurement of bases and base derivatives The content of various bases and base derivatives was measured using high-performance liquid chromatography.

[0069] High-performance liquid chromatograph: with UV detector and 250mm x 4.6mm 5μm SCX column. Mobile phase: 0.1% phosphate Column temperature: 35℃ Detection wavelength: 267nm Various bases and base derivatives were prepared as standard solutions at predetermined concentrations, loaded onto a high-performance liquid chromatograph, and measured to create a calibration curve. After dissolving the test sample in water, it was passed through a 0.22 μm membrane film and loaded for high-performance liquid chromatography analysis. The concentrations of each base and base derivative in the sample were calculated from the calibration curve. The results are shown in Tables 2 and 3. [Table 2] [Table 3]

[0070] As shown in Tables 2 and 3 above, the yeast extracts produced in Examples 1 to 3 contained bases and base derivatives in amounts ranging from 22,000 to 39,000 mg / kg, while the yeast extracts produced in Comparative Examples 1 to 3 contained bases and base derivatives in amounts ranging from 3,000 to 4,500 mg / kg. Therefore, it was found that the yeast extract produced by the manufacturing method provided by the present invention has a high content of bases and base derivatives.

[0071] (Experimental Example 1) The yeast extracts from Examples 1-3, Comparative Examples 1-3, and the prior art CN106282242A were used to culture Bacillus subtilis CCTCC 131157, and the OD of the bacterial cells was used. 600 The final adenosine production was also measured. The specific experimental procedure was as follows: 1. Preparation of fermentation medium: Using 1 L of pure water, the following ingredients were prepared in mass ratio relative to water: glucose 150 g / L, yeast extract powder (yeast extract from Examples 1-3, Comparative Examples 1-3 and Chinese Patent Application Publication No. 106282242) 35 g / L, magnesium sulfate 10 g / L, potassium dihydrogen phosphate 10 g / L, manganese sulfate 0.05 g / L, and copper sulfate 0.01 g / L. After preparation, the medium was sterilized at 121°C for 20 minutes.

[0072] 2. Inoculate Bacillus subtilis CTCCC 131157 into the culture medium and culture for 48 hours, then OD 600 The amount of adenosine produced was also measured. The measurement results are shown in Table 4 below. [Table 4]

[0073] As can be seen from Table 4 above, when the yeast extract provided in Examples 1 to 3 of the present invention is used in a microbial culture medium, the growth of microorganisms can be further promoted.

[0074] The foregoing describes only preferred embodiments of the present invention and is not intended to limit it. Those skilled in the art may make various modifications and changes to the present invention. Any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and principles of the present invention shall be within the scope of protection of the present invention.

[0075] (Note) (Note 1) A yeast extract rich in bases and base derivatives, characterized by containing 20,000 to 40,000 mg / kg of bases and base derivatives.

[0076] (Note 2) The aforementioned yeast extract contains 22,000 to 39,000 mg / kg of bases and base derivatives. Preferably, the base and the base derivative are selected from one or more combinations of adenine, guanine, uracil, cytosine, xanthine, and hypoxanthine. Preferably, the yeast extract contains 2000 to 5000 mg / kg of adenine. And / or, preferably, the yeast extract contains 3000 to 6000 mg / kg of guanine. And / or, preferably, the yeast extract contains 4000 to 7000 mg / kg of uracil. And / or, preferably, the yeast extract contains 1500 to 5000 mg / kg of cytosine. And / or, preferably, the yeast extract contains 8,000 to 11,000 mg / kg of xanthine. Furthermore / or, preferably, the yeast extract is characterized by containing 2000 to 5000 mg / kg of hypoxanthine. Yeast extract as described in Appendix 1.

[0077] (Note 3) The yeast extract contains 10-12% total nitrogen by mass percentage, preferably 10.5-11.8% total nitrogen by mass percentage. Preferably, the yeast extract contains 3.5 to 5.5% amino acid nitrogen by mass percentage, and preferably, the yeast extract contains 4 to 5% amino acid nitrogen by mass percentage. Yeast extract as described in Appendix 1 or 2.

[0078] (Note 4) A method for producing yeast extract as described in any one of the appendices 1 to 3, The method is characterized by comprising the steps of heating yeast milk to 40-60°C, adjusting the pH to 5.0-6.0, adding an enzyme preparation at a mass percentage of 0.1-1% based on the dry weight of the yeast milk, adding a precursor at a mass percentage of 1-5% based on the dry weight of the yeast milk, and allowing it to self-decompose for 15-24 hours. Manufacturing method.

[0079] (Note 5) The enzyme preparation is one or more of the following: nuclease, adenine deaminase, and guanine deaminase. Preferably, the enzyme preparation is a combination of nuclease, adenine deaminase, and guanine deaminase. Preferably, the mass ratio of the nuclease, adenine deaminase, and guanine deaminase is 2.5 to 5:1:1. The manufacturing method described in Appendix 4.

[0080] (Note 6) The method for producing a product according to Appendix 4 or 5, characterized in that the precursor is one or more types of yeast RNA or disodium nucleotides that enhance flavor.

[0081] (Note 7) The process further includes the steps of inactivating the enzyme after autodecomposition, separating the solid and liquid, extracting the liquid, and concentrating it to obtain yeast extract. Preferably, the enzyme is inactivated at 65-75°C. Preferably, the concentration method is characterized by reduced-pressure evaporation. The manufacturing method described in any one of the appendices 4 to 6.

[0082] (Note 8) The manufacturing method according to any one of the appendices 4 to 7, characterized in that the yeast is selected from one or more of the following: budding yeast, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

[0083] (Note 9) The method for preparing the aforementioned yeast milk is: The method is characterized by comprising the steps of inoculating yeast seeds into a culture medium, culturing them for 12 to 24 hours under conditions of pH 4.0 to 6.0 and temperature 30 to 33°C, and collecting yeast cells to obtain yeast milk. The manufacturing method described in any one of the appendices 4 to 8.

[0084] (Note 10) The manufacturing method described in Appendix 9, characterized in that the yeast cell content in the aforementioned yeast milk is 10-15 wt% on a dry matter basis, with the remainder being water.

[0085] (Note 11) The dose is 1-5 wt%, Preferably, the culture medium contains 3-10 g of carbon source, 0.5-1 g of yeast extract, 2-5 g of ammonium sulfate, 1-2 g of magnesium sulfate, 0.5-1 g of potassium dihydrogen phosphate, and 0.1-0.5 g of zinc sulfate per 100 mL of water. Preferably, the carbon source is selected from one or more types of sugarcane molasses, beet molasses, or hydrolyzed sugars. The manufacturing method described in Appendix 9 or 10.

[0086] (Note 12) Yeast extract produced by the manufacturing method described in any one of the appendices 4 to 11.

[0087] (Note 13) Use in food, feed, or culture media of yeast extract produced by any one of the appendices 1 to 3 or appendice 12, or by any one of the manufacturing methods described in appendices 4 to 11.

Claims

1. A yeast extract rich in bases and base derivatives, characterized in that it contains a total amount of bases and base derivatives of 20,000 to 40,000 mg / kg, wherein the bases are a combination of adenine, guanine, uracil, and cytosine, and the base derivatives are a combination of xanthine and hypoxanthine, and the yeast extract contains 8,000 to 11,000 mg / kg of xanthine and 2,000 to 5,000 mg / kg of hypoxanthine.

2. The yeast extract according to claim 1, characterized in that the yeast extract contains a total amount of bases and base derivatives of 22,000 to 39,000 mg / kg.

3. The aforementioned yeast extract contains 2000 to 5000 mg / kg of adenine. Furthermore / or, the yeast extract contains 3000 to 6000 mg / kg of guanine, Furthermore / or, the yeast extract contains uracil at a concentration of 4000 to 7000 mg / kg. Furthermore / or, the yeast extract is characterized by containing 1500 to 5000 mg / kg of cytosine. The yeast extract according to claim 2.

4. The yeast extract is characterized by containing 10-12% total nitrogen by mass percentage. The yeast extract according to claim 1.

5. The yeast extract is characterized in that it contains 10.5 to 11.8% total nitrogen by mass percentage. The yeast extract according to claim 1.

6. The yeast extract is characterized in that it contains 3.5 to 5.5% amino acid nitrogen by mass percentage. The yeast extract according to claim 1.

7. The yeast extract is characterized in that it contains 4 to 5% amino acid nitrogen by mass percentage. The yeast extract according to claim 1.

8. A method for producing yeast extract according to any one of claims 1 to 7, The method comprises the steps of heating yeast milk to 40-60°C, adjusting the pH to 5.0-6.0, adding an enzyme preparation at a mass percentage of 0.1-1% based on the dry weight of the yeast milk, adding a precursor at a mass percentage of 1-5% based on the dry weight of the yeast milk, and allowing it to self-decompose for 15-24 hours, wherein the enzyme preparation is one or more of nucleases, adenine deaminases, and guanine deaminases, and the precursor is one or two of yeast RNA or disodium nucleotides with flavoring properties. Manufacturing method.

9. The manufacturing method according to claim 8, characterized in that the enzyme preparation is a combination of a nuclease, adenine deaminase, and guanine deaminase.

10. The manufacturing method according to claim 9, characterized in that the mass ratio of the nuclease, the adenine deaminase, and the guanine deaminase is 2.5 to 5:1:

1.

11. The manufacturing method according to claim 8, further comprising the steps of inactivating the enzyme after autodecomposition, separating the solid and liquid, and then extracting and concentrating the liquid to obtain a yeast extract.

12. The enzyme is inactivated at 65-75°C. Furthermore / or, the method of concentration is characterized by reduced-pressure evaporation. The manufacturing method according to claim 11.

13. The manufacturing method according to claim 8, characterized in that the yeast is selected from one or more combinations of budding yeast, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

14. The method for preparing the aforementioned yeast milk is: The method is characterized by comprising the steps of inoculating yeast seeds into a culture medium, culturing them for 12 to 24 hours under conditions of pH 4.0 to 6.0 and temperature 30 to 33°C, and collecting yeast cells to obtain yeast milk. The manufacturing method according to claim 8.

15. The manufacturing method according to claim 14, characterized in that the yeast cell content in the yeast milk is 10 to 15 wt% on a dry matter basis, and the remainder is water.

16. The production method according to claim 14, characterized in that the inoculation amount is 1 to 5 wt%, and / or, the culture medium contains 3 to 10 g of carbon source, 0.5 to 1 g of yeast extract, 2 to 5 g of ammonium sulfate, 1 to 2 g of magnesium sulfate, 0.5 to 1 g of potassium dihydrogen phosphate, and 0.1 to 0.5 g of zinc sulfate per 100 mL of water.

17. The manufacturing method according to claim 16, characterized in that the carbon source is selected from one or more types of sugarcane molasses, sugar beet molasses, or hydrolyzed sugars.

18. Use of the yeast extract according to any one of claims 1 to 7 in food, feed, or culture medium.

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