JPH0956361A - Production of yeast extract - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an extract of yeast containing free amino acid and 5'-nucleotide in large amounts and excellent in their balance by subjecting a suspension of yeast cell bodies treated by a high pressure homogenizer to an autolysis under specific conditions. SOLUTION: A suspension of yeast cells is treated by a high pressure homogenizer, and the treated suspension is adjusted to pH6.8-8.5. An enzyme containing an endo-type protease is added to the treated suspension and it is treated at 45-47 deg.C for carrying out autolysis preferably after a pretreatment at 30-43 deg.C for 30min to 1hr. The high pressure homogenizer is preferably a machine capable of increasing a treating pressure to >=700kgf/cm<2> . The protease is preferably added at a concentration of 0.125-0.25mg/ml to the yeast suspension. Further, the termination of the autolysis is commonly carried out by heating at 90 deg.C for 10min. Furthermore, it is preferable to add a cell wall digesting enzyme during the autolysis, and to add chitosan and a polyacrylic acid salt after the heat deactivation because this allows water-insoluble matter to flocculate to be easily removed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a yeast extract containing a large amount of free amino acids and 5'-nucleotides, especially 5'-GMP having a taste.

[0002]

2. Description of the Related Art The main component of yeast extract is free amino acid, and at the same time, it has an effect of imparting umami to foods together with a small amount of 5'-nucleotide. In addition, yeast extract also contains peptides, organic acids, sugars, minerals, etc., which are widely used in the food industry because they have the effect of imparting a complex taste such as richness and depth of taste to foods. .

Most of the yeast extracts on the market are produced by the autolysis method. To start the autolysis, the yeast cell suspension is supplemented with salt, fatty acid ester, organic acid, organic solvent, etc. Addition of auto-digestion promoter (Japanese Patent Publication No. 54-13496, JP-A-55-3409)
No. 6, JP-A-59-109152), mechanical stimuli such as ultra-high pressure hydrostatic treatment, ultrasonic treatment and high-pressure homogenizer treatment (JP-A-2-255059, JP-B-50-255).
No. 39) is known.

During the autolysis reaction, the temperature is usually 37 to 55 ° C.
By keeping the temperature at 1, the protein and RNA in the microbial cells are decomposed into amino acids and 5'-nucleotides by autolytic enzymes. 5'-G among 5'-nucleotides
MP is known to have umami. Further, 5'-AMP produced at the same time does not have umami as it is, but it exerts umami if it is converted to 5'-IMP by the action of deaminase. At that time, since yeast does not have deaminase, it is necessary to add it from the outside. On the other hand, it is known that the coexistence of a cell wall lysing enzyme during self-digestion solubilizes the saccharides in the cell wall and increases the extract yield.

It is also known that the composition of the umami component contained in the extract changes depending on the pH during the autolysis reaction [Japan Food Science 11, 37, (198).
7)]. In other words, 5'which has a taste when it is weakly alkaline
-While many nucleotides are produced, there is a drawback that the amount of free amino acids is low and the extract yield is low at the same time.
The optimum pH of the protease that works for autolysis is 4.5-5.
It is said that the cause of the low alkaline amino acid content and the low extract yield is due to such properties of the protease.

On the other hand, in weakly acidic condition, the amount of free amino acid and the yield of extract are high, but most of RNA is not tasteable 3 '.
-It has the drawback of being broken down into nucleotides. Also,
There is a problem that 5′-nucleotide is easily decomposed by an acidic and highly active dephosphorylating enzyme, and the content of 5′-nucleotide in the product is low.

[0007] Common yeast extracts currently on the market are 5'-nucleotides (mainly 5'-G except for special ones prepared by adding separately prepared 5'-nucleotides).
MP) content is usually about 0.1 to 0.3%. 5'-
It is known that GMP and 5′-IMP not only have umami by themselves, but also show a synergistic effect of umami in the presence of sodium glutamate, and foods containing a large amount of these have a strong umami and are preferable. Also, 5'-GMP, 5'-IMP
Since the umami can be further enhanced by combining it with sodium glutamate or a hydrolyzed protein hydrochloride, which is often used as an umami seasoning, a yeast extract containing a large amount of these is desired. Therefore, yeast extract produced by a general method is added to 5'-GMP produced by another method,
5'-IMP is being added. Here, another method is a method for producing 5'-nucleotide by hydrolyzing RNA extracted and purified from Candida yeast containing a large amount of RNA with 5'-phosphodiesterase produced by Penicillium or the like. . At this time, the 5'-AMP produced is 5'-I by 5'-adenylate deaminase produced by Aspergillus or the like.
You may convert into MP. However, since 5'-GMP and 5'-IMP obtained by such a method are expensive, the price is correspondingly high.

[0008]

The object of the present invention is to obtain a high yield of yeast extract which contains a large amount of free amino acids and 5'-nucleotides, especially 5'-GMP having a taste, and which has a good balance of both component contents. To provide at a rate.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have made a yeast cell suspension treated with a high-pressure homogenizer into a medium to weakly alkaline solution, and added an endo-type protease thereto. It has been found that a yeast extract containing a large amount of free amino acids and 5′-nucleotides in a well-balanced manner and having a high extract yield can be produced by adding an enzyme agent containing the same and performing self-digestion. Furthermore, by adding cell wall lysing enzyme during autolysis, heating and inactivating the enzyme, and then adding chitosan and polyacrylate,
It has been found that the water-insoluble matter becomes a floc and can be easily removed.

That is, the present invention provides: (1) pH of a yeast cell suspension treated with a high-pressure homogenizer
A method for producing a yeast extract, which comprises adjusting to 6.5 to 8.5 neutral to weakly alkaline, adding an enzyme agent containing an endo-type protease to the yeast cell suspension, and allowing it to self-digest. (2) The processing pressure of the high pressure homogenizer is 700 kgf / cm
^The method for producing a yeast extract according to the above (1) which is ² or more; (3) after the high-pressure homogenizer treatment, the above-mentioned (1) or (2) characterized in that the freeze-drying treatment is performed to such an extent that denaturation of the autolytic enzyme is not caused. ) The method for producing a yeast extract as described above; (4) The autolysis is performed by subjecting the yeast cell suspension to 30 to 43 ° C. for 30 minutes.
The method for producing a yeast extract according to any one of (1) to (3) above, which is performed by maintaining the temperature for about 1 minute to about 1 hour and then heating at 43 to 50 ° C .;

(5) The autolysis digests the yeast cell suspension into 3
Maintain at 0 ~ 43 ℃ for 30 minutes ~ 1 hour, then 45 ~
The method for producing a yeast extract according to (4) above, which is carried out by heating to 47 ° C .; (6) A yeast cell wall lysing enzyme is further added during the autolysis to carry out a reaction, and the enzyme is lost by heating. The method for producing the yeast extract according to any one of (1) to (5) above, wherein water insoluble matter is removed by adding chitosan and polyacrylate after activation; (7) Cell wall lysis The method for producing a yeast extract according to (6) above, wherein the enzyme is derived from Arthrobacter bacterium; (8) A yeast extract produced by the method according to any one of (1) to (7) above. Hereinafter, the present invention will be described in detail.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Yeast used The yeast used in the present invention is not particularly limited as long as it is edible, and brewer's yeast, baker's yeast, alcohol yeast, sake yeast and the like can be used. When using brewer's yeast, a yeast extract having a better flavor can be produced by appropriately performing debittering treatment to remove bitterness derived from hops.

(2) High-pressure homogenizer treatment The high-pressure homogenizer used in the present invention has the ability to damage the cell wall and cell membrane, cause exchange of intracellular fluid with extracellular fluid, and have a processing pressure of 700 kgf / cm ^2. Anything can be used as long as it can be raised above. Specific examples include those manufactured by Runny Co., Ltd., Gorin Co., Ltd. and Nippon Seiki Co., Ltd.

Although not limited to a particular theory, the high-pressure homogenizer pierces the cell wall and the cell membrane, and the intracellular pH, which is generally said to be around pH 6 by exchanging intracellular fluid and extracellular fluid, is used. , P of the liquid around the cells
It is considered to have the action of approaching H. At the same time, regarding the added enzyme, it is considered that the high-pressure homogenizer treatment allows pores to be opened in the cell wall and the cell membrane so that the cells can penetrate into the cells.

The treatment pressure during the high-pressure homogenizer treatment may be that required to bring the pH in the cells closer to the external liquid. Normally, if it is 700 kgf / cm ² or more, the 5'-nucleotide, the extract yield, and the amount of free amino acids are increased. You can see the effect. Usually, the number of times of treatment may be once, but when it is performed twice or more, it is desirable to attach a cooling tube or the like to the sample outlet to sufficiently lower the temperature of the sample in order to prevent the activity of the autolyzing enzyme group from being lowered due to overheating of the sample.

(3) Autodigestion by addition of endo-type protease The protease used in the present invention may be any protease having endo-type protease activity. Commercial products, plant and animal tissues, microbial cells and A microbial culture solution or the like is used.

Specific examples of those containing endo-type protease as a main component include, specifically, Alcalase 2.4 L, Neutrase 0.5 L, Protamex MG, Esperase 7.5 L (above, manufactured by Novo Industry), Protease N. , Protease S, Proleather, Pancreatin F, Papain W-40, Bromelain F (above, manufactured by Amano Pharmaceutical Co., Ltd.), Orientase N (manufactured by Hankyu Kyoei Bussan). In addition to those containing endo-type protease as a main component, Protease A, Protease M, Peptidase R, Protease P (above, Amano Pharmaceutical Co., Ltd.), Cochrase SS (Sankyo Co., Ltd.), Flavorzyme (Novo Industry Co., Ltd.) In addition to endo-type activity, it may have exo-type activity.

The endo-type protease itself does not have an action of directly releasing an amino acid from a protein, but it is known to have an action of increasing the amount of released amino acid by a synergistic effect with an exo-type enzyme. We have found in the present invention that free amino acids are increased by newly adding an endo-type enzyme during autolysis of medium to weakly alkaline. This indicates that there is a difference in the degree of activity decrease in the medium to weakly alkaline group among the autolyzed protease group. That is, it is suggested that the activity of the endo-type protease, which has the effect of increasing the extract yield, is significantly reduced, but the activity of the exo-type protease is not reduced as much as that of the endo-type protease. Therefore, it is considered that the addition of a new endo-type enzyme will increase the extract yield and at the same time increase the amount of free amino acids.

The addition timing of the protease is not particularly limited, but there is no particular problem if it is added after the high pressure homogenizer treatment. The more the enzyme is added and the earlier the enzyme is added, the more the amount of free amino acid increases.

The reaction time is a factor that influences the quality of the extract. That is, the reaction start 2 to 4 in the process of autolysis reaction
After time, the amount of 5'-nucleotides becomes the highest and then decreases. On the other hand, the amount of free amino acids increases with time. Therefore, if the amount of 5'-nucleotide is important, the autolysis reaction is stopped in a short time, and if the amount of amino acid is to be increased, the reaction time may be lengthened. 5'-GMP and 5'-IMP are known as tasty 5'-nucleotides. Although 5'-IMP is not contained in the autolysis reaction product, if deamizyme (manufactured by Amano Pharmaceutical Co., Ltd.) is added, it is produced from 5'-AMP by the action of deaminase contained therein. Reaction start pH
For, it is better to start the reaction at pH 6.5 to 8.5 so as to produce more tasty 5'-nucleotides. Although the pH decreases with the start of the reaction, the pH may be maintained by appropriately adding an alkaline solution. When the pH is lower than the above range, the amount of 5'-nucleotide tends to decrease, and when the pH exceeds the above range, the amount of free amino acid tends to decrease. Therefore, in order to increase the contents of both components as much as possible and keep the balance, it is preferable to set the pH within the above range.

The reaction temperature is maintained at 30 to 43 ° C. for about 30 minutes to 1 hour, and then at 43 to 50 ° C., preferably 45 to 47 ° C. To quickly raise the product temperature, a heat exchanger can be used if it is a large-scale facility, but if it is a laboratory scale, it can pass through a stainless steel tube immersed in a constant temperature water tank set to a specified temperature. It becomes possible by doing. For example, inner diameter 3mm, outer diameter 4
The temperature of the sample can be rapidly raised by connecting a syringe to one end of a coiled stainless steel tube of mm, inhaling the cooled sample from the other end, and immersing the coil in a constant temperature water bath.

The protease is contained in the yeast solution in an amount of 0.05 to
0.5 mg / ml, preferably 0.125-0.25 m
For example, it is added at a concentration of about g / ml. If it is less than this, the extract yield is lowered and the synergistic effect with the exo-type self-digesting protease is lowered, and if it is more than this, the extract yield reaches the ceiling.

Termination of the autolysis reaction is usually carried out by heating the sample. The processing temperature at this time is usually 90 ° C. and heating may be performed for about 10 minutes. The supernatant fraction obtained by centrifuging the sample after cooling can be processed into powder, paste or liquid depending on the purpose of use.

In order to liberate a large amount of 5'-nucleotides, yeast cells are suspended at a solid content concentration of about 5 to 15%, and K ₂ PO ₄ is added thereto. Addition concentration is 4
A concentration of 0 mM or less is suitable, and if the concentration is more than 0 mM, the amount of free amino acids decreases, so the concentration may be selected depending on what quality of yeast extract is desired. In order to release the amount of free amino acid and the amount of 5'-nucleotide in a well-balanced manner, 5 to 20 mM is suitable. The timing of addition may be before or after the high pressure homogenizer treatment.

(4) Freeze-drying treatment The yeast suspension treated with a high-pressure homogenizer may be directly subjected to self-digestion, but may be frozen and stored to such an extent that denaturation of the self-digesting enzyme does not occur, or freeze-dried. Alternatively, it may be returned to the aqueous solution when necessary. The amount of 5′-GMP in the obtained yeast extract is increased by performing the freeze-drying process and the process of re-dissolving it thereafter. Before the freeze-drying treatment, some yeast cells remained in which the exchange of yeast intracellular fluid with the extracellular fluid was insufficient. It is considered that this is because the external liquid can penetrate to the inside.

(5) Addition of cell wall lysing enzyme, chitosan and polyacrylic acid salt Not only the extract yield can be improved by adding the cell wall lysing enzyme during autolysis, but also chitosan and polyacrylic acid after heat inactivation are added. By combining with the addition of an acid salt, it becomes possible to flocculate the water-insoluble matter in the self-digesting solution and agglomerate it. As the cell wall lysing enzyme, any enzyme can be used as long as it can lyse the cell wall of yeast. In particular, the enzyme derived from Arthrobacter is preferable in terms of effectiveness. Examples of the product include Zymori Ace (20T, 100T) manufactured by Kirin Brewery Co., Ltd.
Other products of the cell wall lysing enzyme include Tunicase (manufactured by Daiwa Kasei Co., Ltd.), Kitalase (manufactured by KI Kasei Co., Ltd.), and YL-5 (manufactured by Amano Pharmaceutical Co., Ltd.).

The amount of addition for maximizing the effect is 0.078 to 7.8 U / ml, preferably 0.16 to 3.9 U / ml, with respect to the enzyme solution, in the case of Zymolyce 20T as an example. After the addition reaction of the cell wall lysing enzyme, the enzyme is inactivated by heating before the addition of chitosan or polyacrylate. The heat deactivation is performed by, for example, treating at 70 to 95 ° C. for 5 to 30 minutes. The amount of chitosan added is about 4 to 16 v / v% in 1 w / v% chitosan diluted hydrochloric acid solution. In addition, polyacrylate is sodium polyacrylate,
It refers to potassium polyacrylate, etc., but the addition amount of them is 0.5-21 w / v% polyacrylate aqueous solution.
It is about v / v%.

[0028]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Example 1] (1) Production of yeast extract Yeast by-produced in the brewing process (usually called brewer's yeast) was prepared to a solid content concentration of 10% (W / V), and the treatment pressure was 1000 kgf. / Cm ² and treated with a high-pressure homogenizer (manufactured by RANNIE, TYPE 10.51 VH), and this was once made into a freeze-dried powder. At the time of use, it was dissolved in cold tap water so as to have a solid content of 10%, and then adjusted to pH 5.5 to 9.0, and K ₂ HPO ₄ was adjusted to 0.25 mg / ml so as to be 10 mM. So that Protamex MG was added. Sample 15
ml was sucked into a stainless steel tube and immersed in a constant temperature water bath at 35 ° C. for 1 minute, then the sample was transferred to a plastic test tube and heated for a total of 30 minutes. Next, with each test tube 47
The mixture was transferred to a constant temperature water bath at ℃ and further heated for 7 hours and 30 minutes.
The test tube may be appropriately shaken and stirred. To stop the reaction, the test tube was placed in boiling water and heated for 10 minutes. The supernatant obtained by centrifugation was freeze-dried and subjected to the following analysis.

(2) Analysis of yeast extract The yeast extract sample obtained in (1) was analyzed. (Amount of Free Amino Acid) The amount of free amino acid was determined by summing up the amounts of each amino acid determined by an amino acid analyzer.

(Amount of 5'-GMP) The amount of 5'-GMP was determined by high performance liquid chromatography under the following conditions. Column: MCI GEL CDR-10 Diameter: 4.6 mm x 250 mm (manufactured by Mitsubishi Kasei Co., Ltd.) Eluent: 1 M ammonium acetate buffer (pH 3.5) Pump: Tosoh CCPD Flow rate: 1 ml / min Detector: Tosoh UV8010 Measurement wavelength : 254 nm Calculator: Tosoh SC-8010 Free amino acid amount and 5'-nucleotide amount are the number of mg contained per 1 g of the solid content of the extract component (unit: mg / g)
Or the number of mg contained in the reaction vessel (mg / tube)
It was expressed by. The extract yield was expressed as a percentage of the solid content of the extract component with respect to the raw yeast solid content.

The results of the analysis are shown in Table 1. As a comparative example, the analysis results of a sample that has undergone an autolysis reaction without adding an enzyme are shown. As is clear from Table 1, the extract yield, free amino acid content,
The amount of 5'-GMP increases. In particular, pH 6.5-8.5
The amount of free amino acid 5'-
Both GMP amount is increasing.

[0033]

[Table 1]

Example 2 The high pressure homogenizer treatment liquid prepared in the same manner as in Example 1 was used without freeze-drying.
K ₂ HPO ₄ was added to adjust the pH to 7.5, and the pH was adjusted to 7.5.
After adjusting to Protamex MG 0.25mg / m
It was added so as to be 1. Of this, 15 ml was used in Example 1
In the same manner as shown in (3), the mixture was heated at 35 ° C. for 30 minutes and then at 47 ° C. for another 5 hours and 30 minutes for autolysis. The methods of stopping the reaction, solid-liquid separation, and pulverization were in accordance with the method of Example 1. The analysis results are shown in Table 2. As shown in Table 2, the enzyme yield increased the extract yield. In addition, the total amount of 5'-GMP increased with the increase in the total amount of free amino acids per reaction vessel.

[0035]

[Table 2]

Example 3 The high-pressure homogenizer treatment liquid prepared in the same manner as in Example 1 was once made into a freeze-dried powder, which was dissolved in tap water so that the solid content was 10%, and the pH was 7.
What was adjusted to 5 was once put into a reaction container by 15 ml. To this, K ₂ HPO ₄ was added so that the concentration was 10 mM, and various protease preparations (<1> to <13>) were 0.25 mg / ml for powder products and 0.25 μl for liquid products.
/ Ml was added. After heating this for 30 minutes in a constant temperature water bath at 35 ° C., it was further heated at 47 ° C. for 5 hours and 30 minutes to carry out an autolysis reaction. During the self-digestion reaction, the reaction vessel may be appropriately shaken and stirred. Stop reaction,
The solid-liquid separation and the powdering were carried out according to the method of Example 1.

Table 3 shows the analysis results of the obtained yeast extract powder.
It was shown to. As a comparative example, the analysis result of the sample which carried out the autolysis reaction without adding the enzyme is shown. As shown in Table 3, not only enzyme preparations containing exo-type protease activity (<10> to <13>) under intermediate to alkaline conditions, but also protease preparations containing only endo-type protease activity (<1> to <9>) The increase in extract yield and the amount of free amino acids were also remarkable in the above.

[0038]

[Table 3]

Example 4 The high-pressure homogenizer treatment liquid prepared in the same manner as in Example 1 was once made into a freeze-dried powder, which was dissolved in tap water so that the solid content was 10%, and the pH was adjusted to 7.5. It was adjusted. K ₂ HPO ₄ was added to 15 ml of the solution so that the concentration was 10 mM, Protamex MG was added at 0.25 mg / ml, or Neutrase 0.5 L was added at 0.75 μl / ml. This is 35
After heating for 30 minutes in a constant temperature water bath at ℃, the temperature was raised to 47 ℃, and further heated for 5 hours and 30 minutes for self-digestion.
As a comparative example, the same procedure was performed without adding the enzyme. The methods of stopping the reaction, solid-liquid separation, and pulverization were in accordance with the method of Example 1. The analysis results are shown in Table 4. As in Example 2, the amount of 5'-GMP increases with the increase of the amount of free amino acid.

[0040]

[Table 4]

Example 5 80 L of brewery yeast suspension (solid content 6.25%) was treated with a high-pressure homogenizer to give 30
It was put in a 0 L stainless steel jar. The processing pressure of the high-pressure homogenizer was 1000 kgf / cm ² . Add 25 ml of Neutrase 0.5 L to this and add 10 m
K ₂ HPO ₄ was added to make M. After adjusting the pH to 7.5 using 5N potable soda, start heating,
After about 1 hour, it reached 47 ° C. After 40 minutes, the pH was adjusted to 7.5 using a caustic soda, and after 16 hours, steam was passed through a jacket attached to a stainless steel jar to raise the temperature to 90 ° C. and kept for 10 minutes to stop self-digestion. . After cooling, the mixture was centrifuged and the supernatant was concentrated with a thin film centrifugal concentrator, further pulverized and analyzed. The analysis results are shown in Table 5.

[0042]

[Table 5]

Example 6 Beer yeast suspension (solid content 1
To 100 L of 0%), an equal amount of 1.25% NaCO ₃ solution was added and stirred for 30 minutes, and the supernatant was removed by centrifugation. Water was added to this and the supernatant was removed by centrifugation. Add water to add 10
%, Adjust with high pressure homogenizer, cool down to 30
It was placed in a 0 L stainless steel jar. The high-pressure homogenizer treatment pressure was 1000 kgf / cm ² . The pH was adjusted to 7.5 with 5N caustic soda, and 6 g of Protamex MG and 4 g of Zymoly Ace were added and heating was started. After 30 minutes, the temperature reached 47 ° C. A heat exchanger was used for heating. Six hours after the start of heating, steam was passed through the jacket to keep the temperature of the product at 90 ° C. for 10 minutes and then cooled to 70 ° C. 15.6 L of dilute hydrochloric acid solution of chitosan was added thereto while gently stirring. A dilute hydrochloric acid solution of chitosan was prepared by suspending 156 g of chitosan powder in 15.6 L of water and then adding 156 ml of 12N hydrochloric acid to dissolve it. 0.5 w / v% after stirring for 10 minutes
20.8 L of sodium polyacrylate solution was added. The water-insoluble matter in the solution was in the form of flocs. The water-insoluble matter was removed with a mesh or the like, then concentrated, further pulverized and analyzed. The analysis results are shown in Table 6.

[0044]

[Table 6]

[0045]

INDUSTRIAL APPLICABILITY According to the present invention, a large amount of free amino acids and 5'-nucleotides, particularly 5'-GMP having a taste, which are preferably used in the field of food industry, and the balance of the content of both components is provided. A good yeast extract can be produced in high yield.

Claims (8)

[Claims] 1. A yeast cell suspension treated with a high-pressure homogenizer is adjusted to pH 6.5 to 8.5 neutral to weakly alkaline, and an enzyme agent containing an endo-type protease is added to the yeast cell suspension. A method for producing a yeast extract, which comprises subjecting the yeast extract to self-digestion. 2. The processing pressure of the high pressure homogenizer is 700 k.
The method for producing the yeast extract according to claim 1, which has a gf / cm ² or more. 3. The method for producing a yeast extract according to claim 1 or 2, wherein after the treatment with a high-pressure homogenizer, a freeze-drying treatment is performed to such an extent that denaturation of the autolyzing enzyme does not occur. 4. A method of autolyzing a yeast cell suspension to 30-4.
Maintain at 3 ℃ for 30 minutes to 1 hour, then 43-50 ℃
The method for producing a yeast extract according to any one of claims 1 to 3, wherein the method is performed by heating the yeast extract. 5. A method of autolyzing a yeast cell suspension for 30 to 4
Maintain at 3 ℃ for 30 minutes to 1 hour, then 45-47 ℃
The method for producing a yeast extract according to claim 4, wherein the method is performed by heating the yeast extract. 6. When autolyzing, yeast cell wall lysing enzyme is further added to carry out the reaction, and after inactivating the enzyme by heating, chitosan and polyacrylic acid salt are added to remove water-insoluble matter. The method for producing the yeast extract according to any one of claims 1 to 5, which is characterized. 7. The method for producing a yeast extract according to claim 6, wherein the cell wall lysing enzyme is derived from Arthrobacter. 8. A yeast extract produced by the method according to claim 1.