JP2016036291A - Method for manufacturing simmered and softened mushrooms - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing mushrooms that are simmered and softened so as to obtain such firmness that even a person having difficulty in chewing such as elderly person can easily eat (simmered and softened mushrooms), while maintaining its original shape of mushrooms.SOLUTION: Mushrooms are soaked in an aqueous enzyme solution comprising: a first decomposing enzyme including any activity of cellulase activity and hemicellulase activity; and a second decomposing enzyme including at least one of activities selected from the group consisting of pectinase activity, glucanase activity, or chitinase activity. After decreasing or increasing the pressure of the aqueous solution in which the mushrooms is soaked, the aqueous solution in which the mushrooms is soaked is maintained in the temperature range of 35 to 55°C. Before the aqueous enzyme solution is maintained in such temperature range, adipic acid is added thereinto.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing soft mushrooms that can be eaten easily even by a person with weak chewing force such as an elderly person without chewing with teeth.

  In recent years, with the progress of an aging society, many foods for those who have difficulty chewing or swallowing have been released. However, some of these foods have the problem that the texture varies greatly, there are parts that are not soft, and the appetite is not appreciable visually because the shape of the original ingredients is not maintained. To do.

  For this reason, the technique which softens a foodstuff, maintaining the original shape is proposed. For example, Patent Document 1 discloses a technique in which a plant material is frozen and thawed, then left under reduced pressure, and rapidly softened while maintaining its shape using a method of rapidly introducing an enzyme into the plant food material. Yes. Similarly, Patent Document 2 has an enzyme introduction step of introducing an enzyme into a food material by subjecting the raw material food to a reduced pressure treatment, contacting the liquid component containing the enzyme while maintaining the reduced pressure state, and then increasing the pressure. Disclosed is a method for producing an enzyme-containing food product.

  Patent Document 3 discloses a method of softening a plant material without variation in hardness by contacting the plant material with an enzyme treatment solution containing an enzyme and then performing a reduced pressure treatment a plurality of times.

  Patent Document 4 discloses a method for producing an enzyme degradation product by treating a fruit body of a mushroom with hot water, followed by enzymatic treatment with chitinase.

JP 2006-223122 A International Publication No. 2010/114120 JP 2012-055191 A JP 2014-42512 A

  The methods disclosed in Patent Documents 1 to 3 are suitable for vegetables, beans, potatoes or fruits. However, mushrooms are greatly different from these plant materials in the structure and components of the tissue, so even if the methods disclosed in Patent Documents 1 to 3 are used, elderly people with weak chewing ability can eat. To a certain extent, it has been difficult to sufficiently soften the original mushrooms while maintaining their shape. The method disclosed in Patent Document 4 is a method for efficiently decomposing mushroom fruit body parts to obtain an enzyme degradation product, and is not a method for softening mushrooms as food.

  Here, in order to soften the mushrooms with a size as close to the shape of the original mushrooms as possible without cutting them into small pieces, it is necessary to carry out enzyme treatment for a long time. However, it was confirmed that if the enzyme treatment time is increased, the number of bacteria in the enzyme-containing aqueous solution in which mushrooms are immersed increases, and the softened mushrooms are not suitable for eating.

  It is an object of the present invention to provide a method for producing mushrooms (soft mushrooms) that have been softened to a hardness that can be easily eaten even by elderly people with weak chewing force while maintaining the shape of the original mushrooms. To do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have carried out decompression and decompression operations in a state where mushrooms are immersed in an enzyme aqueous solution containing an enzyme such as cellulase, and then the enzyme It was confirmed that mushrooms can be sufficiently softened by performing the enzyme treatment in the temperature range of 35 ° C. to 55 ° C., which is near the optimum temperature.

  However, for mushrooms, the enzyme treatment takes a long time compared to other plant materials such as leafy vegetables, root vegetables or fruits, so the flavor of mushrooms often deteriorates due to the growth of microorganisms (miscellaneous bacteria). It became clear that there was a problem that it was not suitable for eating. Therefore, the present inventors have further studied a method for preventing microbial growth during the enzyme treatment, and as a result, by adding adipic acid to the enzyme aqueous solution containing the enzyme, the enzyme reaction (hydrolysis reaction) is performed. The present inventors have found that a unique effect that cannot be obtained with other organic acids, such as suppressing the growth of microorganisms, without inhibiting the softening of mushrooms, has been completed, and the present invention has been completed.

Specifically, the present invention
Mushrooms, a first degrading enzyme having either cellulase activity or hemicellulase activity;
A second degrading enzyme having one or more activities selected from the group consisting of pectinase activity, glucanase activity or chitinase activity;
Step A soaked in an enzyme aqueous solution containing
Maintaining the mushrooms immersed in the enzyme aqueous solution for a certain period of time under reduced pressure; and
Step C for returning mushrooms immersed in the enzyme aqueous solution to normal pressure;
Holding the mushrooms immersed in the enzyme aqueous solution in a temperature range of 35 to 55 ° C .;
Have
It is related with the manufacturing method of the soft mushroom characterized by adding adipic acid to the said enzyme aqueous solution before the said process D is started.

  After step D, it is preferable to further include step E for inactivating the first decomposing enzyme and the second decomposing enzyme contained in the enzyme aqueous solution by washing mushrooms and further heat-treating.

  It is preferable to repeat step B and step C a plurality of times.

  From the viewpoint of working efficiency, it is preferable to add adipic acid to the aqueous enzyme solution in step A.

  The concentration of adipic acid added to the enzyme aqueous solution is preferably 0.005 mol / L or more and 0.1 mol / L or less.

  Mushrooms are foods that are elastic and difficult to eat by those who have difficulty chewing as they are, and are difficult to soften by conventional enzyme treatment. However, according to the present invention, it is possible to produce soft mushrooms that are soft enough to be crushed between the tongue and the upper jaw while maintaining the shape of the mushrooms.

  Hereinafter, modes for carrying out the present invention will be described with reference to examples. The present invention is not limited to the following description.

(Process A)
The term “mushrooms” used in the present invention means edible mushrooms in general such as edible shiitake, maitake, enokitake, shimeji, eringi or mushroom, and includes both fresh and dried products. “Mushrooms” includes a so-called “umbrella” portion and “shaft” portion, and also includes other edible portions.

  The shape and size of the mushrooms are not particularly limited, but they are not finely cut so that the shape of the original mushrooms is not maintained as in the case of chopped, but the so-called “bite size” that is close to the original shape of the mushrooms. Is preferable. This is because maintaining the appearance (shape) of the original mushrooms as much as possible is preferable from the viewpoint of maintaining appetite during eating. In the present invention, even such a so-called “bite-size” mushroom can exhibit a unique effect of being easily chewed and swallowed by softening.

  For example, (1) In the case of shiitake, the diameter of the umbrella is about 2 cm to 5 cm; (2) In the case of enoki or maitake, the length is about 2 cm to 7 cm; In this case, it is preferable to adjust the length to about 5 cm to 8 cm and the width and thickness to about 0.5 to 1 cm from the viewpoint of maintaining the original shape of the mushrooms. If the size of the mushrooms is originally within the above range, the mushrooms may be used as it is without being cut.

  In the present invention, first, mushrooms are a first degrading enzyme having one of cellulase activity and hemicellulase activity, and one or more kinds selected from the group consisting of pectinase activity, glucanase activity or chitinase activity. Immerse in an aqueous enzyme solution containing the bilytic enzyme. At this stage, it is preferable from the viewpoint of work efficiency to add adipic acid to the aqueous enzyme solution. However, before starting step D, adipic acid may be added to the aqueous enzyme solution in a step after step A. Good.

  A commercially available enzyme reagent can be used as the degrading enzyme. The enzyme activity in the aqueous enzyme solution is 10 IU or more and 10,000 IU or less for the first degrading enzyme, 10 IU or more and 10,000 IU or less (in the case of pectinase), or 0.01 IU or more and 10 IU or less (per gram of dried mass of the mushrooms to be immersed) Glucanase or chitinase is preferred. However, considering cost and workability such as time required for the process D (enzyme treatment process), the first degrading enzyme is 50 IU to 2000 IU, the second degrading enzyme is 50 IU to 2000 IU (in the case of pectinase) or 0.1 IU More preferably, it is 10 IU (in the case of glucanase or chitinase).

  The origin or dosage form of the commercially available enzyme reagent used as the first decomposing enzyme and the second decomposing enzyme is not limited, and may be a powder product or a liquid product.

  The adipic acid concentration in the enzyme aqueous solution is 0.005 mol / L or more and 0.1 mol / L or less considering the balance between the effect of preventing the growth of various bacteria in the subsequent process D and the acidity remaining in the mushrooms after the process D. Preferably, it is more preferably 0.01 mol / L or more and 0.07 mol / L or less.

  In order to maintain the activity of the first decomposing enzyme and the second decomposing enzyme, the pH of the aqueous enzyme solution in which mushrooms are immersed is preferably adjusted as necessary. From the viewpoint of the stability of the enzyme reaction, it is practically preferable that the pH is appropriately adjusted so as to be in the range of pH 3.0 to 5.0 at the start of Step D.

(Process B and Process C)
Subsequent to step A, the mushrooms immersed in the enzyme aqueous solution are brought into a reduced pressure state (step B), and then returned to normal pressure (step C), whereby the first decomposing enzyme and the second decomposing enzyme aqueous solution are contained inside the mushrooms. Can be permeated uniformly, and the softening effect by the enzyme reaction in the step D can be enhanced. Further, when adipic acid is added before the start of step B, adipic acid can be uniformly permeated into the mushrooms, and the bacteriostatic effect of adipic acid in step D can be enhanced. The process B may be any conditions as long as at least part of the liquid or gas present in the voids inside the mushrooms is discharged. For example, the reduced pressure state is maintained for about 10 to 180 seconds at a pressure of 20 kPa or less. Is preferred.

  In order to sufficiently permeate the first decomposing enzyme and the second decomposing enzyme into the mushrooms, it is preferable to repeat Step B and Step C two or more times. When mushrooms are large, etc., it is preferable to repeat 4 times or more. After Step C, Step P may be performed in which mushrooms immersed in the enzyme aqueous solution are pressurized to a normal pressure or higher.

(Process D)
Subsequent to Step C, the mushrooms immersed in the enzyme aqueous solution are held at a temperature range of 35 to 55 ° C. for a predetermined time. When softening a vegetable material such as leaf vegetables, root vegetables or fruits, the holding time is usually about 2 to 6 hours. On the other hand, in the case of mushrooms, it is set appropriately depending on the type and size of the target, for example, if one side is less than 1 cm, 8-12 hours, if one side is 1 cm or more It takes about 12-30 hours. When softening mushrooms of the so-called “bite size” in which the shape (appearance) of the original mushrooms as the main object of the present invention is maintained, it is longer than when softening finely cut mushrooms Retention time is required. In this case, miscellaneous bacteria easily propagate in an aqueous solution containing an enzyme, and thus it is necessary to suppress the growth of miscellaneous bacteria (microorganisms).

  In the present invention, by adding adipic acid to the aqueous enzyme solution (enzyme treatment solution), as described above, it is possible to effectively prevent the propagation of various bacteria even in long-term enzyme treatment without inhibiting the activity of the degrading enzyme. obtain. Such an effect is an effect specific to adipic acid that cannot be obtained by using other organic acids or antibacterial agents.

  In addition, when it exceeds 48 hours, even if adipic acid is added, it may not be possible to suppress the growth of germs in the enzyme aqueous solution. Therefore, appropriately adjust (1) the concentration of the enzyme in the aqueous enzyme solution; (2) the number of repetitions of step B and step C; (3) the reaction temperature: etc. so that the mushrooms are sufficiently softened within 48 hours. It is desirable.

(Process E)
After completion of Step D, the mushrooms that have been subjected to the enzyme treatment are taken out from the aqueous enzyme solution and washed with tap water or the like. Furthermore, mushrooms are heat-treated. By this heat treatment, the enzyme remaining in the mushrooms is deactivated, and the mushrooms are further sterilized. In addition, when mushrooms are immediately cooked and eaten after the process D, only the washing operation is performed, and the heat treatment can be omitted. The method for the heat treatment may be any method that allows the enzyme to be inactivated, and may include retort sterilization, boiling, steaming, or heating by a microwave oven.

[Example 1]
An aqueous enzyme solution containing 0.1% by mass of cellulase and pectinase and 0.039 mol / L (0.57% by mass) of adipic acid was prepared, and 600 mL thereof was taken in a beaker. 100 g of dried mushroom shiitake with an umbrella diameter of 2 to 3 cm and a thickness of 1 cm to 2 cm was rehydrated and placed in a beaker, and the mushroom was immersed in an enzyme aqueous solution. At this time, cellulase (first degrading enzyme) in the enzyme aqueous solution is about 720 IU / g with respect to shiitake dry mass, and pectinase (second degrading enzyme) is about 480 IU / g with respect to shiitake dry mass. . The beaker was put into a vacuum kettle, maintained for 1 minute under a reduced pressure of 10 kPa, and then returned to normal pressure. This decompression operation and decompression operation were repeated 5 times.

  After the fifth re-pressure operation, the beaker was left in a 40 ° C. incubator for 27 hours for enzyme treatment. Thereafter, shiitake (treated shiitake) after the enzyme treatment was taken out of the beaker and washed with tap water. After washing, shiitake mushrooms were placed in a heat-resistant plastic film together with the seasoning liquid, sealed, and heated at 115 ° C. for 60 minutes using a hot water retort apparatus.

[Example 2]
A shiitake processed product was obtained in the same manner as in Example 1 except that an enzyme aqueous solution having an adipic acid concentration of 0.015 mol / L (0.22% by mass) was used.

[Example 3]
A shiitake processed product was obtained in the same manner as in Example 1 except that an aqueous enzyme solution having an adipic acid concentration of 0.005 mol / L (0.072% by mass) was used.

[Comparative Example 1]
A shiitake processed product was obtained in the same manner as in Example 1 except that an aqueous enzyme solution to which adipic acid was not added was used.

[Comparative Example 2]
A shiitake processed product was obtained in the same manner as in Example 1, except that an enzyme aqueous solution containing 0.039 mol / L (0.75 mass%) citric acid was used instead of adipic acid.

[Comparative Example 3]
A shiitake processed product was obtained in the same manner as in Example 1, except that an enzyme aqueous solution containing 0.015 mol / L (0.29% by mass) of citric acid was used instead of adipic acid.

[Comparative Example 4]
A shiitake processed product was obtained in the same manner as in Example 1 except that an enzyme aqueous solution containing 0.039 mol / L (0.23% by mass) of acetic acid was used instead of adipic acid.

[Comparative Example 5]
A shiitake processed product was obtained in the same manner as in Example 1, except that an enzyme aqueous solution containing 0.039 mol / L (0.52% by mass) of malic acid was used instead of adipic acid.

[Comparative Example 6]
A shiitake processed product was obtained in the same manner as in Example 1, except that an enzyme aqueous solution containing 0.039 mol / L (0.59% by mass) tartaric acid was used instead of adipic acid.

[Comparative Example 7]
A shiitake processed product was obtained in the same manner as in Example 1 except that an enzyme aqueous solution containing 0.039 mol / L (0.35% by mass) of lactic acid (DL-lactic acid) was used instead of adipic acid.

[Comparative Example 8]
A shiitake processed product was obtained in the same manner as in Example 1 except that an enzyme aqueous solution containing 0.039 mol / L (0.46% by mass) of succinic acid was used instead of adipic acid.

[Comparative Example 9]
Shiitake processed product in the same manner as in Example 1 except that an aqueous enzyme solution containing 0.4% by mass of a commercially available bacteriostatic agent (referred to as bacteriostatic agent A) containing alum as a main component instead of adipic acid is used. Got.

[Comparative Example 10]
Shiitake processing in the same manner as in Example 1 except that an aqueous enzyme solution containing 0.2% by mass of a commercially available bacteriostatic agent (referred to as bacteriostatic agent B) containing sodium acetate as a main component instead of adipic acid is used. I got a product.

[Comparative Example 11]
A shiitake processed product in the same manner as in Example 1 except that an aqueous enzyme solution containing 0.4% by mass of a commercially available bacteriostatic agent (referred to as bacteriostatic agent C) based on glycine instead of adipic acid is used. Got.

<Evaluation of softening rate of shiitake processed product>
The hardness of the shiitake processed products obtained in Examples 1 to 3 and Comparative Examples 1 to 11 was examined to determine whether or not they were sufficiently softened. The hardness of shiitake processed products is determined by counting the number of pieces that can be crushed by pressing a shiitake processed product (or a fragment thereof) between the tongue and the upper jaw one by one, and pressing the tongue against the upper jaw. It was measured. Then, among 50 processed shiitake mushrooms (or fragments thereof), the ratio of the number of crushed pieces to the total number was calculated as “softening rate”.

  For the maitake processed product of Example 15 and the eringi processed product of Example 16 to be described later, the softening rate was calculated by the same operation as that for the shiitake processed product.

  The “softening rate” showed almost no difference between the shiitake processed product immediately after the enzyme treatment and the shiitake processed product after the retort sterilization treatment.

<Measurement of general viable count>
About Examples 1-3 and Comparative Examples 1-11, the number of general viable bacteria in the enzyme aqueous solution immediately after enzyme treatment was measured. The aqueous enzyme solution was appropriately diluted with physiological saline and smeared on a standard agar medium (SMA) in a petri dish. The petri dish was cultured at 37 ° C. for 48 hours, and then the number of colonies was counted to calculate the general viable cell count (cfu / g) in the enzyme aqueous solution.

  Table 1 shows the softening rate and the number of general viable bacteria of Examples 1 to 3 and Comparative Examples 1 to 4. Table 2 shows the softening rate and the general viable count of Comparative Examples 5 to 11.

From Table 1 and Table 2, about Examples 1-3, the softening rate of the shiitake processed product was 95% or more, and the number of general viable bacteria was 10 ⁴ order or less. On the other hand, in Comparative Examples 2 to 8 using organic acids other than adipic acid, the softening rate sometimes exceeded 80%, but the number of general viable bacteria was 10 except for Comparative Example 6 using tartaric acid. It was confirmed that the number of germs was so high that it was ⁷ orders or more and food sanitation problems occurred. In Comparative Example 6 where the softening rate was low, it was estimated that cellulase and pectinase activities were inhibited by tartaric acid. Also in Comparative Examples 9 to 11 using a bacteriostatic agent instead of an organic acid, the number of general viable bacteria was 10 ⁵ cfu / g or more, and it was judged that there was a problem in food hygiene.

  In general, when an organic acid is used for food for bacteriostatic purposes, acetic acid having a high bacteriostatic effect or inexpensive citric acid is often used. In addition, bacteriostatic agents are often used for foods such as sugar beets, salads, beverages or soups. However, under long-term enzyme treatment conditions for sufficiently softening mushrooms, the effect of adipic acid is not effective in that it inhibits microbial growth and does not inhibit the activities of the first and second degrading enzymes. It was confirmed that it was significantly higher than organic acids or bacteriostatic agents.

<Examination of temperature conditions in process D>
The temperature in the thermostatic chamber at the time of the enzyme treatment (step D) of Example 1 was changed from 30 ° C to 60 ° C. The enzyme treatment time was unified to 27 hours. Table 3 shows the measurement results of the softening rate of shiitake processed products after retort sterilization treatment.

  From Table 3, it was confirmed that when the enzyme treatment temperature is in the range of 35 ° C. to 55 ° C., the softening rate of the shiitake processed product can be made 70% or more by the enzyme treatment for 27 hours. It was also confirmed that when the enzyme treatment temperature was in the range of 40 ° C. to 50 ° C., the softening rate was about 90% or more. On the other hand, when the enzyme treatment temperature was 30 ° C., the softening rate was only 60%, and at 60 ° C., the measured value decreased to less than half of the softening rate at 55 ° C. Thus, it has been found that the temperature during the enzyme treatment is preferably 35 ° C. or more and 55 ° C. or less, and more preferably 40 ° C. or more and 50 ° C. or less.

<Types of mushrooms, types of enzymes used and amounts added>
[Example 8]
A shiitake processed product was obtained in the same manner as in Example 1 except that the enzyme treatment step (step D) was performed at 40 ° C. for 24 hours.

[Example 9]
A shiitake processed product was obtained in the same manner as in Example 8 except that hemicellulase was used instead of cellulase.

[Example 10]
A shiitake processed product was obtained in the same manner as Example 8 except that glucanase was used instead of pectinase. The glucanase (second degrading enzyme) in the enzyme aqueous solution is 4 IU / g based on the dry weight of shiitake mushroom.

[Example 11]
Shiitake processed products were obtained in the same manner as in Example 8 except that chitinase was used instead of pectinase and the enzyme treatment was performed at 45 ° C. for 30 hours. Chitinase (second degrading enzyme) in the enzyme aqueous solution is 1 IU / g with respect to shiitake dry mass.

[Example 12]
A shiitake processed product was obtained in the same manner as in Example 8 except that the cellulase addition amount and the pectinase addition amount were reduced. Cellulase (first degrading enzyme) and pectinase (second degrading enzyme) in the enzyme aqueous solution are each 100 IU / g with respect to the dried shiitake mass.

[Example 13]
A shiitake processed product was obtained in the same manner as in Example 8 except that dry shiitake with an umbrella diameter of 3 to 5 cm was used.

[Example 14]
Using fresh shiitake mushrooms with a diameter of 3 to 5 cm of umbrella, cellulase (primary degrading enzyme) and pectinase (second degrading enzyme) in the aqueous enzyme solution without reconstitution with water were each 500 IU / A shiitake processed product was obtained in the same manner as in Example 8 except that g and 300 IU / g were used.

[Example 15]
A processed maitake mushroom was obtained in the same manner as Example 14 except that raw maitake having a length of 3 to 5 cm, a width and a thickness of 0.5 to 1 cm was used.

[Example 16]
A processed ering product was obtained in the same manner as Example 14 except that raw eringi having a length of 5 to 8 cm, a width and a thickness of 0.5 to 1 cm was used.

[Comparative Example 14]
Shiitake processed product in the same manner as Example 8 except that the first degrading enzyme (cellulase or hemicellulase) is not used, an aqueous enzyme solution containing chitinase and glucanase is used, and the enzyme treatment is performed at 45 ° C. for 30 hours. Got. The chitinase and glucanase in the enzyme aqueous solution were 5 IU / g and 20 IU / g, respectively, with respect to the shiitake dry mass.

[Comparative Example 15]
A shiitake processed product was obtained in the same manner as in Example 8 except that cellulase was used as the first decomposing enzyme and no second decomposing enzyme was used. The cellulase in the enzyme aqueous solution was 1000 IU / g with respect to the dried shiitake mass.

  About Examples 8-16 and Comparative Examples 14-15, the number of general viable bacteria in the enzyme aqueous solution immediately after an enzyme treatment was measured by the method similar to the above. Moreover, about the obtained mushroom processed product, the softening rate was measured by the method similar to the above. Tables 4 and 5 show the results.

Table 4 and Table 5 show that by combining cellulase or hemicellulase (primary degrading enzyme) with pectinase, glucanase or chitinase (secondary degrading enzyme), the softening rate by enzymatic treatment without finely cutting mushrooms. It was confirmed that it can be softened to 80% or more. Moreover, the number of general viable bacteria in the enzyme aqueous solution after the enzyme treatment was less than 10 ³ cfu / g, and it was confirmed that there was no problem in food hygiene. On the other hand, as in Comparative Examples 14 and 15, when only the first degrading enzyme or the second degrading enzyme was used, the number of general viable bacteria was suppressed to less than 10 ³ cfu / g by the effect of adipic acid, The softening rate was about 60% or less, and it was confirmed that mushrooms could not be sufficiently softened.

  In Examples 13 to 16, mushrooms larger than the mushrooms used in other examples were treated, but a high softening rate of 84% or more could be achieved.

  The method for producing softened mushrooms of the present invention is useful in the fields of medical and food manufacturing industries as a method for producing processed mushroom products suitable for nursing foods and the like.

Claims (5)

Mushrooms, a first degrading enzyme having either cellulase activity or hemicellulase activity;
A second degrading enzyme having one or more activities selected from the group consisting of pectinase activity, glucanase activity or chitinase activity;
Step A soaked in an enzyme aqueous solution containing
Maintaining the mushrooms immersed in the enzyme aqueous solution for a certain period of time under reduced pressure; and
Step C for returning mushrooms immersed in the enzyme aqueous solution to normal pressure;
Holding the mushrooms immersed in the enzyme aqueous solution in a temperature range of 35 to 55 ° C .;
Have
A method for producing soft mushrooms, characterized in that adipic acid is added to the enzyme aqueous solution before the start of the step D.   2. The method according to claim 1, further comprising a step E of inactivating the first decomposing enzyme and the second decomposing enzyme contained in the enzyme aqueous solution by washing mushrooms and further heat-treating after the step D. Of softening mushrooms.   The method for producing softened mushrooms according to claim 1 or 2, wherein Step B and Step C are repeated a plurality of times.   The method for producing softened mushrooms according to any one of claims 1 to 3, wherein adipic acid is added to the aqueous enzyme solution in the step A.   The method for producing softened mushrooms according to any one of claims 1 to 4, wherein the concentration of adipic acid added to the aqueous enzyme solution is 0.005 mol / L or more and 0.1 mol / L or less.