JP5748502B2 - Natto production container and method for producing natto using the same - Google Patents

Description

  The present invention relates to a container for producing natto, and more specifically, a container for producing natto that has an excellent balance between airtightness and air permeability and is suitable for heating and holding after a fermentation process, and natto having excellent storage stability using the same. It relates to a manufacturing method.

  In general, natto is shipped as a product through each process of washing, dipping, steaming, natto fungus application, container filling, fermentation, storage, and packaging. First, in the washing process, the soybeans used as a raw material are removed of dirt and foreign matter by a washing machine, and are put into a water tank to remove dirt attached to the soybean surface. In the next soaking step, the soy tissue is softened by soaking the washed soybean in water. In the steaming process, the soaked soybeans are steamed with a high-pressure kettle. In the Bacillus natto spraying step, Bacillus natto is sprayed on the steamed soybean at a temperature of about 80 to 90 ° C. Thereafter, in the container filling and fermentation process, the boiled beans to which the above-mentioned natto bacteria are dispersed are loaded into a natto container and fermented in an environment of a predetermined temperature and humidity in a fermentation chamber. Fermentation is stopped by lowering the temperature of the natto product. Then, in a preservation | save process, natto after fermentation is cooled and preserve | saved at 5 degrees C or less with a refrigerator.

  Natto after the fermentation process causes deterioration of quality over time, such as generation of ammonia odor, generation of white precipitate (tyrosine) on the surface of natto, reduction of stringing, generation of bitterness, and drying. For this reason, in order to suppress deterioration of quality over time, secondary fermentation after fermentation is suppressed by performing low-temperature storage and low-temperature circulation, and deterioration of quality over time is prevented to some extent.

  However, even if the natto after the fermentation process is stored at low temperature and distributed at low temperature, there is a problem that the period during which the quality of natto can be maintained and the original taste of natto can be maintained is only about one week. In addition, the production of natto takes 2-3 days from order receipt to shipment through the above-mentioned steps. When ordering natto manufacturing, the demand at the time of shipment is predicted and the production of the estimated amount of natto is started, but the actual demand may be small and there is a disadvantage that the manufactured natto must be discarded .

  Then, the natto package which improved the feeding property of natto by preventing the drying of natto in processes, such as ripening after fermentation, packaging, shipment, and storage, is proposed (refer patent document 1). The natto package is capable of producing natto without using a perforated film in a tray or cup, and the natto package has a natto package in the center excluding the contact portion with the flange of the lid of the natto package. A structure having a predetermined gap between the side wall and the side wall is provided. In addition, a fermented natto container has been proposed that smoothly ferments the filled boiled beans, prevents drying around the boiled bean mass, and prevents redness due to air burning (see Patent Document 2). The natto container main body is configured so that the container main body and the lid are in close contact with each other, and in the step of filling the natto container with boiled beans, the lid is in close contact with the container main body when the lid is closed after filling with boiled beans. Therefore, the lid can be prevented from being half-opened by the frictional resistance. Furthermore, a method for producing natto has been proposed in which the natto container after the fermentation process is film-wrapped or shrink-wrapped (see Patent Document 3).

JP 2002-249188 A Registered Utility Model Publication No. 3122569 JP 2001-218866 A

  However, the natto package disclosed in Patent Document 1 can supply oxygen necessary for fermentation into the natto package when filling and fermenting steamed soybeans in the natto manufacturing process. Although it is possible to prevent drying of soybeans without using it, the original quality of natto is not sufficiently maintained for a long period of time. Moreover, although the natto container disclosed by patent document 2 can prevent that the quality of natto deteriorates, it prevents redness by drying around the boiled beans lump and air-burning. It is just something that can be done, and the quality of natto cannot be maintained for a long time. Furthermore, the method for producing natto disclosed in Patent Document 3 has a problem in that the container body after the fermentation process is film-wrapped or shrink-wrapped, which requires time and complexity. It was.

  The present invention has been made in view of the above situation, and a container for producing natto excellent in balance between airtightness and air permeability suitable for each step of filling, fermentation, and heating, and this container are used. It aims at providing the manufacturing method of natto excellent in the preservability and taste which were.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have kept the humidity in the natto container body after the fermentation process constant, and airtightness in order to minimize condensation in the container. It has been found that the above-mentioned problems can be solved by using a container for producing natto having an excellent balance of air permeability, and the present invention has been completed. That is, the present invention specifically provides the following.

(1) a container body in which a recess for storing natto is formed;
A lid that is formed to cover the concave portion of the container body and does not have an air hole;
A rectangular frame-shaped flange formed on the upper surface of the container body and a seal portion for bonding the lid body are provided,
A convex part is formed inside the lid to fit the container body,
A container for producing natto, wherein the seal part is adjusted so as to maintain a balance between airtightness and air permeability of the lid and the container body.

  (2) The container for producing natto according to (1), wherein at least one or more of the sealing portions are provided on each side of the lid.

  (3) The container for producing natto according to (1) or (2), wherein the seal portion is provided at the center of each side of the lid.

(4) a step of cooling natto after completion of the fermentation process;
A step of heating and holding a natto production container filled with natto after the cooling step at a temperature higher than the fermentation temperature of natto at a multi-stage temperature;
A method for producing natto, comprising a step of cooling the container for producing natto that has been subjected to the heating and holding step.

  (5) The method for producing natto according to (4), wherein the container for producing natto is the container for producing natto according to any one of (1) to (3).

(6) The step of heating and holding is characterized by heating and holding for 15 minutes at a temperature T ₁ that is equal to or higher than the fermentation temperature of natto, and then for 75 minutes at a temperature T ₂ that is 5 to 15 ° C. lower than the temperature T _1. The method for producing natto according to (4) or (5).

  (7) After the step of cooling the natto production container that has undergone the above heating and holding step, the natto production container is further packaged by pillow packaging and cooled and stored (4) to ( 6) The manufacturing method of natto in any one of description.

  (8) Natto excellent in preservability and taste obtained by the production method according to any one of (4) to (7).

  (9) By adjusting the balance of the airtightness and breathability of the natto production container by modifying the structure of the natto production container, the storage stability and taste of the natto contained in the natto production container are adjusted. how to.

  According to the natto production container and the natto production method of the present invention, the balance of airtightness and breathability of the natto production container body is maintained, so that it has a good natural flavor of natto, generation of ammonia odor, natto It is possible to provide natto excellent in long-term storage with little occurrence of white precipitate (tyrosine) on the surface, reduced stringiness and bitterness.

It is the schematic which shows typically one Embodiment of the container for natto manufacture. It is a top view of the cover body of the container for natto manufacture which increased the seal part. It is a top view of the cover body of the container for natto manufacture which has not increased the seal part. It is a photograph showing the state of the container main body for natto manufacture and the cover which increased the seal part after a heating and holding process. It is a photograph showing the state of the container main body for natto manufacture and the cover which has not increased the seal part after a heating holding process. It is the figure which showed the state of the elapsed time at the time of using the container for natto manufacture which gave the three-way seal part in Example 1, and the temperature in a natto manufacture container. It is the figure which showed the elapsed time at the time of the heat processing of the sample which carried out the pillow packaging in Example 2, and performed the preservation | save test of natto, and the state of the temperature in a natto manufacturing container.

[Natto production container]
Hereinafter, an embodiment of the natto production container 10 of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic view specifically showing an embodiment of a container 10 for producing natto of the present invention. The natto manufacturing container 10 includes a container main body 12 in which an accommodation recess 11 for accommodating natto is formed inside the container, and a lid 13 that covers the opening of the container main body 12. The housing recess 11 for housing the natto has a concave cross-sectional shape. A convex portion 14 is formed on the inner surface of the lid body 13 so that the container body 12 is fitted to the lid body 13. The lid 13 is a lid that does not have air holes. Here, the container main body 12 and the lid body 13 may be integrally formed of a synthetic resin such as polystyrene, polyethylene, or polypropylene. Also, the container body and the lid can be made of different materials. For example, the container body can be made of foamed synthetic resin and the lid can be made of a vinyl film.

  FIG. 2 is a top view of the lid 13 of the container 10 for producing natto of the present invention. As apparent from FIG. 2, the container 10 for producing natto of the present invention has a rectangular frame-shaped flange 15 formed on the upper surface of the container body 12 and a seal portion 16 for bonding the lid body 13. A plurality are provided. In the natto manufacturing container 10 of FIG. 2, three seal portions 16 (16 a, 16 b, and 16 c) are provided in accordance with the center of each side of the lid body for bonding the lid body 13. By providing these seals, it is possible to ferment natto during fermentation and ripening in the natto manufacturing process, and also prevent drying of natto in the container body containing natto in the process of heating and holding. Is something that can be done. By preventing the natto from drying, the original stringing of natto can be maintained, and the occurrence of bitterness and tyrosine can be suppressed. That is, the container for producing natto of the present invention is adjusted so as to maintain the balance between the airtightness and air permeability of the lid body and the container main body by increasing the number of seal portions.

  FIG. 3 is a top view of a lid body 21 of a commercially available normal natto manufacturing container 20 (not shown). As shown in FIG. 3, usually, in a natto manufacturing container, a sealing body 24 for bonding a flange 23 and a lid 21 of a container body 22 (not shown) to which the lid 21 is bonded. Are provided at two locations (24a, 24b). The top surface of the lid of the natto container has a plurality of air holes (25). As described above, the container for producing natto of the present invention does not have an air hole in the lid, as compared with a container for producing ordinary natto, but has a seal portion for bonding the flange of the container body and the lid. Since it is increased, the balance between airtightness and air permeability is excellent, and a large gap does not occur between the flange of the container body and the lid body even after the heating and holding process described later.

  The number of seals provided in the natto production container of the present invention is not particularly limited as long as the balance between the airtightness and air permeability of the container body can be maintained. In addition, the number of the sealing portions varies depending on the heat stability of the material constituting the container body for producing natto and the material constituting the lid. That is, in the natto production container of the present invention, when natto is ripened and heated and held, an appropriate gap that can maintain a balance between airtightness and air permeability between the flange of the container body and the lid is provided. The most important point is that it can be formed, the humidity in the container body can be maintained, and drying of natto can be prevented. Further, the location of the seal portion is not particularly limited as long as it can form an appropriate gap that can maintain a balance between airtightness and air permeability between the flange of the container body and the lid. Although not intended, for example, it can be provided at the center of each side of the container body as described above. Further, various types of seals can be employed from the same viewpoint as described above. Moreover, it is preferable to provide each seal part at equal intervals. By providing the seal portions at equal intervals, it is possible to set an appropriate gap in the natto production container, thereby maintaining a uniform environment in the container system such as temperature and humidity of the natto production container. This is preferable because it is possible.

  The method for forming the seal portion is not particularly limited as long as it can maintain a balance between airtightness and air permeability between the flange of the container main body and the lid body. In addition to applying ultrasonic treatment to the bonding part for bonding the lid to form a seal part, the seal part is formed by bonding with a synthetic resin by heating or applying a predetermined adhesive to the seal part and bonding can do.

[Manufacturing method of natto]
Next, the manufacturing method of the natto of this invention is demonstrated. The method for producing natto of the present invention comprises a step of cooling natto after the fermentation process, and a natto production container filled with natto that has undergone the cooling step at a temperature that is equal to or higher than the fermentation temperature of natto, and a multistage temperature. And a step of cooling the natto production container that has undergone the heating and holding step. Hereinafter, each step will be described.

(Fermentation process)
In the natto production method of the present invention, the fermentation process means a normal natto fermentation process. That is, in the above fermentation process, after soybeans used as a raw material for natto are steamed, the steamed soybeans obtained are inoculated with natto bacteria, filled in a container for natto production, and then at a temperature of about 35 to 45 ° C. It ends by holding for about 10 to 20 hours.

  The natto that can be used in the above fermentation process includes normal natto, black beans, and split walnuts, as well as mustard, wasabi, soy sauce, miso, salt, bonito extract, yuzu extract, shichimi, grated radish, and curry. Natto to which seasonings such as flour are added in advance may be used. These seasonings may be liquid, powder or semi-fluid. When the above seasoning is liquid, the natto stringing after the seasoning is added is reduced, the natto is easy to handle during filling at the time of manufacture, and the stringing is appropriate even when eating. It is preferable. When the seasoning is a solid, it is preferable because it can be a natto product with less wateriness.

  In addition to the above seasonings, fermented foods such as green onions, leek, onions, ginger, bonito shavings, sesame seeds, kimchi, cheese butter, etc. Etc. can also be added as ingredients.

(Cooling process after completion of fermentation process)
Next, in the manufacturing method of natto of this invention, the process of cooling the natto after the said fermentation process completion is provided. In addition to cooling for natto fermentation stop and aging, in the present invention, the natto after the fermentation process is cooled and stored for several days, thereby suppressing the bitter taste of natto and improving the storage stability. . In the above process, first, the temperature is gradually lowered from the fermentation temperature of about 40 ° C. to room temperature, and finally cooling is performed at the cooling temperature. The temperature for finally cooling natto is preferably 3 to 5 ° C. Setting to the above temperature range is preferable because the natto flavor and storage stability are improved. In addition, the cooling time in the above process is not particularly limited as long as it can suppress the bitter taste of natto, but is preferably 5 ° C. or less and 5 to 15 days from the viewpoint of the manufacturing process. .

(Process to heat and hold the container for natto production)
Next, the natto manufacturing method of the present invention includes a step of heating and holding a natto-producing container filled with natto at a temperature equal to or higher than the fermentation temperature of natto at a multi-stage temperature.

  Here, as a natto manufacturing container filled with natto that has undergone a cooling process after completion of the fermentation process, the seal part is not increased, and a normal natto manufacturing container having an air hole in the lid May be used. However, when the natto production container is used, it is necessary to provide an appropriate refrigerated storage period after the heat treatment as described later, and then perform a packaging process such as pillow packaging. Moreover, in the manufacturing method of natto of this invention, the container for natto manufacture of this invention demonstrated above can also be used. That is, when the natto production container of the present invention is used, in the step of heating and holding the natto production container filled with natto after completion of the fermentation process, the balance between airtightness and air permeability of the natto production container Can be held. In other words, it is possible to maintain the humidity in the container body for producing natto and to prevent the natto from drying, and to maintain the quality of natto stringing, bitterness and the like. In order to ferment soybeans, which is the raw material of natto, the environment necessary for fermentation is required. However, if the container body for natto production is completely sealed, there is not enough air for fermentation. Not enough fermentation of natto can proceed. Therefore, in the method for producing natto of the present invention, fermentation of natto is advanced while maintaining a balance between airtightness and air permeability by forming an appropriate gap in the container for producing natto.

  In the heating and holding step, since it is necessary to suppress drying of natto, it is preferable to seal the natto manufacturing container body. For this reason, in the natto manufacturing method of the present invention, a lid that does not have air holes in order to maintain various conditions such as temperature, humidity, and pressure inside the container body for producing natto in the heating and holding step. And use a container for natto production with an increased seal. In the present invention, by adopting a lid that does not have air holes and increasing the seal part, the drying of the natto production container body is suppressed more than the conventional natto production container, and the quality of natto Prevent decline.

  The method for producing natto of the present invention includes a step of heating and holding a natto-producing container filled with natto that has undergone a cooling step after completion of the fermentation step at a temperature equal to or higher than the fermentation temperature of natto at a multistage temperature. The heating temperature in the heating and holding step is a temperature equal to or higher than the fermentation temperature, and is usually 50 to 100 ° C, preferably 60 to 80 ° C. When the temperature to be heated and held is within the above temperature range, the original stringing of natto can be maintained, the occurrence of bitterness and tyrosine can be suppressed, the storage stability of natto is improved, and the taste of natto is improved. It is preferable because it can be maintained.

  The heating and holding step is preferably performed in the atmosphere. When the heating and holding step is performed in the air, the relative humidity is preferably in the range of 80 to 100%. It is preferable that natto is heated under the relative humidity within the above range, so that the natto surface is not dried and the storage stability of natto is improved. In addition, steam is sent into the atmosphere of the natto manufacturing container from a steam heating device or the like, the heat capacity in the heating device is increased, a rapid temperature increase is possible, and drying of the natto manufacturing container body can be prevented. .

  The heating time in the heating and holding step is not particularly limited as long as it is a necessary time to improve the necessary storage stability of natto. It can be suitably set according to various conditions such as the heating and holding temperature, the relative humidity, the volume of the accommodating recess for accommodating natto inside the container body, and the pressure described above. Usually, it is preferably performed for about 15 to 150 minutes. The heating and holding may be maintained so as to satisfy various conditions such as the heating temperature, relative humidity, and pressure. For example, by preparing a storage container for heating and holding and sending air having a predetermined temperature, humidity, and pressure into the storage container, conditions for the process of heating and holding the storage container can be set. . In addition, air with adjusted temperature and humidity can be sent to evaporate the water after the heating and holding step so that the condensation in the container is minimized.

The heating and holding process is performed in multiple stages. This is because by performing the heating and holding process in multiple stages, it is possible to prevent the bitterness of natto from increasing due to the influence of the enzyme if heating is performed in a short time in each heating and holding process. For example, the heating and holding process is made into two stages, and the heating temperature and the heating time are set. Then, forced in various satisfy steam such as the temperature in a constant temperature and humidity chamber, for 15 minutes a stage heating and holding at temperatures T _1, then, than temperature T ₁ of the two-stage heating and holding 5 at 15 ℃ lower temperature _{T 2} may be between 75 minutes. Moreover, depending on various conditions such as the type of natto and the container body for producing natto, the heating and holding can be set in multiple stages as appropriate, such as three stages and four stages, and the heating and holding temperatures T ₁ , T _{2 and the} like can be set for each stage. The temperature can be appropriately set in the range of 50 to 100 ° C.

  In the heating and holding step, it is necessary to carry out the process so as to minimize the mixing of steam into the natto filled in the natto production container. This is because when natto is mixed with water droplets, the natto becomes watery and the original stringing of natto becomes worse, which is not preferable. The heating and holding conditions are so-called high-temperature and high-humidity conditions. Therefore, when the natto production container of the present invention or a normal natto production container is used, water vapor entering through the gap between these containers is rapidly cooled. This is because dew condensation occurs and moisture is present in the natto production container.

(Cooling process of natto production container after heating and holding process)
Therefore, in the natto manufacturing method of the present invention, after the heating and holding step, a cooling storage step of storing for several days after cooling is further provided. Since the cooling temperature is also within the range of room temperature, it can be set by sending air at room temperature or the like with a fan or the like. The gas that can be used in the cooling step is not particularly limited as long as it does not change the quality of natto filled in the natto production container, but examples thereof include air, water vapor, and nitrogen. be able to. In the heating and holding step, it is preferable to use water vapor when the natto in the container has been dried.

  The natto production container filled with natto after the fermentation process is heated and held, and the natto after the cooling storage process is cooled to a storage temperature and shipped as a product. The natto produced by the natto production method of the present invention is preferably refrigerated at 3 to 5 ° C, but can be stored for several days or more at a room temperature of about 10 to 20 ° C higher than these temperatures. Conceivable. The natto produced by the natto production method of the present invention can be stored at 10 ° C. for a period exceeding 40 days, maintains the original stringing of natto, and suppresses the occurrence of bitterness and tyrosine. It is.

(Cooled storage after pillow packaging)
Further, in the natto manufacturing method of the present invention, the natto production container having the lid body having no air holes and the sealing portion and the lid body having the air holes in the lid body and the sealing body having no air holes, and the sealing portion is not increased. Containers can be used. That is, even when the natto production container of the present invention is used as a natto production container, or even when a commercially available natto production container that does not increase the seal portion is used, after the heating and holding step This is because the balance between airtightness and air permeability in the natto production container after the cooling process can be maintained by pillow-wrapping the natto production container after the cooling process. That is, in the natto manufacturing method of the present invention, the natto manufacturing container is a natto manufacturing container with an increased number of the above-described sealing parts (a three-way sealed container). Even if it is a commercially available container for natto production having a normal number, by applying pillow packaging, the conditions such as temperature, humidity, pressure, etc. inside the container body for natto production are maintained, The balance between airtightness and air permeability can be maintained.

  Pillow wrapping refers to pulling out the wound film, forming it into a cylindrical shape with a former, heat-sealing both sides parallel to the film drawing direction (horizontal sealing), and then heat sealing (vertical sealing) perpendicular to the drawing direction. ), And heat sealing can be performed by continuously wrapping with a belt conveyor device or the like. As a packaging material for pillow packaging, a film composed of a surface layer and a back surface layer can be used, and the back surface layer can be obtained by laminating a resin that adheres by heat.

[Method of adjusting storability and taste of natto]
The method for adjusting the storage stability and taste of natto according to the present invention adjusts the balance between airtightness and air permeability of the natto production container filled in the natto production container by modifying the structure of the natto production container. This is what you do. The modification of the structure of the natto production container refers to the modification of the seal portion for bonding the rectangular frame-shaped flange formed on the upper surface of the natto production container body and the lid as described above. The modification of the seal portion is not particularly limited, and examples thereof include the number of seal portions provided in the lid, the location of the seal portion, and the type of the seal portion. The modification of the seal portion can be appropriately adopted for the required natto depending on the quality and the quality retention period.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example at all.

<Natto fermentation>
After immersing the small soybean for natto used as a raw material in water at room temperature for about 10 to 20 hours, the obtained immersed soybean was cooked at a temperature of 128 ° C. and a pressure of 1.8 kg / cm ² for 40 minutes. Next, commercially available natto bacteria solution (Miyagino natto bacteria, manufactured by Miyagino natto factory) is appropriately added to the obtained steamed soybean so that it becomes 1-2 × 10 ³ per 1.0 gram of the above boiled beans. Dilute and inoculate. Then, it was made to ferment at 40 degreeC for about 20 hours. Thereafter, the fermented natto was stored in a refrigerator (about 4 ° C.) for one day, and after the fermentation process, cooled natto was obtained.

<Filling Natto into a container for natto production>
A container for producing natto consisting of a container body and a lid used in the method for producing natto of the present invention was produced. In addition, this container for natto production does not have an air hole on the upper surface of the lid. After the fermentation process, the natto production container body was incorporated so that the total mass of the cooled natto was 40 to 50 grams. Then, the lid and the natto production container body are heat sealed, put in a container and sent to the fermentation process. In the actual process, the charging machine puts boiled beans in the natto container body, heat-seals a film called a film, puts only natto products within the standard through weight and metal detector, Send to fermentation process. After completion of fermentation, the container body for natto production was covered with a lid to form a seal part. As a seal part that bonds the flange and lid, a natto production container (hereinafter referred to as “three-way seal container”) is provided with one seal part on each side of the natto container body, and the seal part is increased in three directions. It was said that). The sealing part is formed by welding the lid and the flange of the container body for producing natto with a simple ultrasonic welder (Honda Electronics Co., Ltd., electric welding machine, trade name “ultrasonic welder”). went.

<Example 1>
After completion of the fermentation step, a natto production container (three-way seal container) having a sealed portion increased in a natto production container filled with cooled natto was heat-treated under predetermined heating and holding conditions. The heat treatment was performed using a low-temperature steam heating device (manufactured by Tom Co., Ltd.). The heating and holding was performed in two stages. First, heating was performed at 85 ° C. for 15 minutes, and then heat treatment was performed at 70 ° C. for 75 minutes. The photograph showing the state of the container main body for natto manufacture which increased the seal part used by the present Example in FIG. 4 and the cover body was shown. FIG. 6 shows the relationship between the heating time and the internal temperature of the container body for producing natto. The temperature of the natto manufacturing container body was measured by placing a sensor (Thermocron SL type “DS1922L”) in the natto manufacturing container.

  According to FIG. 4, the natto production container (three-way seal container) with the increased seal used in Example 1 forms an appropriate gap between the lid and the container body even after heat treatment. You can see that you can. That is, it became clear that the balance between the airtightness and the air permeability of the natto production container main body can be maintained by increasing the seal part.

(Evaluation of natto quality)
Then, the natto after heat processing was preserve | saved at 5 degrees C or less, and the quality (bitterness, stringing, generation | occurrence | production of tyrosine) of natto after passing predetermined days at 10 degreeC after that was evaluated. In addition, the bitterness and stringing of natto were evaluated as follows. Furthermore, these evaluations were put together and the evaluation of preservability as natto was regarded as a comprehensive evaluation. The evaluation results are shown in Table 1 below. Evaluation methods and evaluation criteria are as follows.

The natto after a predetermined number of days elapsed was extracted from the container for natto production, and 10 monitors ate the food, and the average of the evaluation was taken and evaluated according to the following evaluation criteria.
(Bitterness evaluation) ○ ・ ・ ・ No problem
△ ... Slightly bitter
□ ・ ・ ・ It has a bitter taste
× ・ ・ ・ very bitter (string pull evaluation) ○ ・ ・ ・ no problem
△ ・ ・ ・ Slightly weak
□ ・ ・ ・ Very weak
× ・ ・ ・ Flip off (Tyrosine generation) ・ ・ ・ When white granular material is generated on the surface of natto (Comprehensive evaluation) ○ ・ ・ ・ No problem
△ ・ ・ ・ within limits but slightly degraded
□ ・ ・ ・ within the limit but considerably deteriorated
× ・ ・ ・ below the limit

(Evaluation of natto hardness)
Moreover, about the hardness of the natto after heat processing, it evaluated by extracting the natto after heat processing and measuring a breaking strength. For the measurement of breaking strength, 20 natto grains after a predetermined number of days have passed are extracted as measurement samples, 95% confidence intervals are calculated from the t-distribution from the measurement results of 20 grains, and the maximum, minimum and average breaking strengths are calculated. Value. In addition, the measurement of breaking strength used the breaking measuring apparatus (The product of a San Kagaku company, product name "RHOEO TEX TYPE SD-700") as a measuring apparatus according to the natto test method. The evaluation results are shown in Table 3 below.

<Comparative Example 1>
After completion of the fermentation process, natto is manufactured in the same manner as in Example 1 except that a natto manufacturing container (normally sealed container) that does not increase the sealing part is used as a natto manufacturing container that is filled with cooled natto. did. The photograph showing the state of the container main body for natto manufacture and the cover body which did not increase the seal part used in the comparative example 1 in FIG. 5 was shown. Moreover, about the obtained natto, the quality evaluation, hardness evaluation (breaking strength), and the weight change in a natto manufacturing process were evaluated. Table 2 shows the results of natto quality evaluation, and Table 3 shows the hardness evaluation.

  According to FIG. 5, it can be seen that a large gap is formed between the lid body and the container body after heating the container for producing natto used in Comparative Example 1 in which the seal portion is not increased. That is, since the seal part is not increased, it has been found that the balance between airtightness and air permeability of the natto production container main body cannot be maintained.

  According to Table 1, the natto produced using the natto production container (three-way seal container) with the increased seal portion of Example 1 is bitter even after 39 days have passed since the incorporation date. It is understood that there is no generation of tyrosine and no generation of tyrosine. The stringing has become “△ (slightly weak)” from the 11th day from the date of incorporation, but even after the 11th day, the level of the stringing can be maintained without decreasing. It has become a thing.

  As described above, in the comprehensive evaluation evaluated in Table 1 in consideration of all the bitterness, stringing and tyrosine generation of natto, “○ (no problem as a natto product)” on the 1st to 10th day from the incorporation date. After the 11th day from the date of inclusion, it becomes “△ (within the limits but slightly deteriorated)”, and it is understood that the quality as a natto product can be maintained even after 39 days from the 11th day. It was. That is, by using a natto production container (three-way sealed container) with an increased number of parts that seal the container body and lid as a natto production container, the quality of the natto product is maintained for a long period of one month or more. I can see that

  On the other hand, natto produced using the natto production container (normally sealed container) of Comparative Example 1 described in Table 2 has no bitterness, but after 32 days from the date of incorporation, tyrosine was produced. It is recognized that the quality as a natto product cannot be maintained. With regard to stringing, it becomes “△ (slightly weak)” from the 11th day from the date of incorporation, then becomes “□ (very weak)” after the 24th day, and “× (paralyzed” after the 31st day. ) ”. As described above, in the comprehensive evaluation in consideration of all the bitterness, stringing, and tyrosine generation of natto evaluated in Table 2, after the 11th day from the date of incorporation, “△ (within the limit but slightly deteriorated)” From the 24th day onwards, “□ (within the limits but considerably deteriorated)”, and after the 31st day, “× (below the limit of best taste)”, and the quality as a natto product cannot be maintained. It has been found. That is, the natto produced in Example 1 can maintain the quality of natto even after 39 days from the date of incorporation, whereas the natto produced in Comparative Example 1 has a date of incorporation. In just 22 days, the quality of natto could not be maintained. As a result, it is possible to maintain the quality of natto even at a storage temperature of 10 ° C. by producing natto using a natto container (three-way seal container) with an increased sealing portion as a natto production container. It shows that the possible period can be extended over a long period of about 2 weeks (14 days) or more.

  Furthermore, according to Table 3, the hardness (breaking strength) of natto produced in Example 1 is substantially constant (average value 81.8 to 94.7) from 5 to 32 days from the date of incorporation. On the other hand, the hardness (breaking strength) of the natto produced in Comparative Example 1 decreased with time, and the value after 5 days from the date of incorporation was 95.1 (average value). The value after the lapse of days is 68.0 (average value), and the change in the hardness of natto is large. This result shows that the natto production container (three-way seal container) used in Example 1 can suppress moisture drying, and the natto hardness (breaking strength) can be a constant value. It is shown. On the other hand, the natto production container (usually sealed container) used in Comparative Example 1 cannot suppress moisture drying, so that the drying in the natto production container proceeds and the natto hardness (breaking strength) decreases. Is considered to have occurred.

<Examples 2 and 3>
After the heating and holding step, natto was produced in the same manner as in Example 1 except that the cooled natto production container was pillow-wrapped. In Example 2, a container for natto production without increasing the seal portion was used, and the natto container cooled after the heat treatment was subjected to pillow packaging. In Example 3, the natto production container (hereinafter also referred to as “three-way seal container”) having an increased number of seal portions used in Example 1 was used, and the natto container cooled after the heat treatment was subjected to pillow packaging. .

  FIG. 7 shows the relationship between the heating time and the internal temperature of the container body for producing natto. Table 4 (Example 2) and Table 5 (Example 3) show the evaluation results of the quality of natto, and Table 6 (Examples 2 and 3) shows the measurement of the breaking strength.

  According to Table 4, the natto produced in Example 2 was evaluated as “◯ (no problem)” even after 52 days had elapsed from the incorporation date, and tyrosine was also generated. It has never been. About bitterness, it is "(no problem)" from 38 days after inclusion, and it turns out that the bitterness has not generate | occur | produced. As described above, it was found that the quality as a natto product can be maintained until 38 to 40 days have elapsed from the incorporation date in the comprehensive evaluation taking into account all the bitterness, stringing and tyrosine generation shown in Table 4. In other words, even when a commercially available natto production container is used as a natto production container, it is possible to produce a natto product over a long period of time by simply packaging the natto production container after heat treatment and cooling. As it became clear that the quality can be maintained.

  According to Table 5, the natto produced in Example 3 is “○ (no problem)” for stringing even after 52 days have passed since the date of incorporation, and sufficient stringing have. Moreover, about generation | occurrence | production of tyrosine, generation | occurrence | production was not recognized at all even after the lapse of 52 days from the date of incorporation, indicating a good result. The bitterness is “◯ (no problem)” even after 41 days from the date of incorporation, and the quality of “△ (some bitterness)” is maintained even after 43 days. ing. That is, the natto produced in Example 3 uses a container for natto production (three-way seal container) with an increased sealing portion, and further heat-treats and cools the container, and then applies simple pillow packaging. The quality as a natto product can be maintained over a long period of 52 days or more.

  According to Table 6, the breaking strength of natto produced in Example 2 is almost constant (average value 66.4 to 78.2) from 10 to 44 days from the date of incorporation, and Example 3 The rupture strength of the natto produced in the above is also substantially constant (average value 65.3 to 74.7). These results show that the balance between airtightness and air permeability can be maintained by using pillow-wrapped natto production containers after cooling or using a natto production container (three-way seal container) with an increased seal. It shows that the hardness (breaking strength) of natto can be set to a constant value.

<Reference Example 1>
After completion of the fermentation process, natto was produced in the same manner as in Example 1, except that the natto production container filled with cooled natto was subjected to pillow packaging without heat treatment after the fermentation process. Table 7 shows the results of evaluation of natto quality, and Table 8 shows the measurement of breaking strength.

  According to Table 7, even if the natto production container filled with cooled natto after completion of the fermentation process is manufactured without any heat treatment after completion of the fermentation process, a simple pillow is produced after the fermentation process. By packaging, it was found that the quality excellent in natto's bitterness and stringing can be maintained even after 18 days have passed since the incorporation. Given that the shelf life of normal natto products is about 10 days, even if the heat-treated natto production container used in Example 1 is used, natto products can be produced by simple pillow packaging. It is understood that the period during which the quality of the image can be maintained can be extended by about twice. Moreover, according to Table 8, the hardness (breaking strength) of natto also shows a favorable numerical value from the date of incorporation until 14 days have passed, indicating that the quality of the natto product is maintained.

<Example 4, Comparative Examples 2 and 3>
The weight change in each process of natto production due to the difference in containers for natto production was measured. As a natto production container, a natto production container (three-way seal container, Example 4) with an increased number of seals used in Example 1, an air hole in the lid, and the lid and the container body Natto production container (normally sealed container, Comparative Example 2) without increasing the seal part of the natto, and a container similar to the natto production container used in Example 1, but without increasing the seal part (Normally sealed container, Comparative Example 3) was used and natto was produced in the same manner as in Example 1 by the natto production method of the present invention. In Example 4 and Comparative Examples 2 and 3, the weight of the whole natto production container after incorporation, the weight of natto after completion of the fermentation process, and the weight after completion of heating and holding were measured. The results are shown in Table 9. In Example 4 and Comparative Example 2, the weight average value of 95 natto production samples was used as measurement data, and in Comparative Example 3, the weight average value of 195 natto production samples was used as measurement data.

  According to Table 9, the total weight at the time of incorporation of Example 4 and Comparative Examples 2 and 3 is substantially the same, but the weight change after heat treatment is 0.16 for Example 4 (three-way sealed container). Gram, Comparative Example 2 and Comparative Example 3 are 0.20 and 0.25 grams, respectively. From this, it is understood that by using a natto production container (three-way seal container) with an increased seal part, the balance between the airtightness and air permeability of the container can be maintained and drying of natto can be prevented. Is done.

<Example 5, Comparative Example 4>
After completion of the fermentation process, a natto production container (Example 5) in which a seal part is increased in a natto production container filled with cooled natto and a natto production container (Comparative Example 4) in which the seal part is not increased. Each was used in the same manner as in Example 1 to produce natto. Tables 10 and 11 show the results of evaluating the quality of natto after elapse of a predetermined number of days from the inclusion in Examples and Comparative Examples, respectively.

  Moreover, about the natto manufactured in Example 5 and the comparative example 4, the weight of the whole natto manufacturing container after progress for 32 days from the filling date of a natto and a filling date was measured. Table 12 shows the measurement results. In addition, the measurement of the weight of the whole natto manufacturing container extracted 10 samples arbitrarily from the natto manufactured about the Example and the comparative example, measured about each of these samples, and also calculated the average value of 10 samples. The results are shown in Table 13. Furthermore, about the natto manufactured by the said Example and the comparative example, the breaking strength after each day progress from a filling day was measured. Table 14 shows the measurement results.

  According to Table 10, the natto produced in Example 5 is “○ (no problem)” for stringing even after 45 days from the date of incorporation, and sufficient stringing is performed. Have. Similarly, regarding the generation of tyrosine, even after 45 days have passed since the date of incorporation, no occurrence was observed, indicating a good result. The bitterness is “◯ (no problem)” even after 45 days from the date of incorporation, and the quality of natto is maintained. That is, the natto produced in Example 5 maintains the quality as a natto product over a long period of 45 days or more by using a container for natto production (three-way seal container) with an increased number of seals. It is possible to do.

  On the other hand, according to Table 11, “bitterness” is “O (no problem)” even after 46 days have elapsed from the date of incorporation, but stringing is from the date of incorporation. After the 36th day, “◯ (no problem)” changes to “Δ (somewhat weak)”, and thereafter “Δ (somewhat weak)” is maintained. The overall evaluation of the quality as a natto product became “△ (within the limits but slightly deteriorated)” after 36 days, and the quality as a natto product was slightly inferior. From the results of Example 5 and Comparative Example 4, by using a natto production container (three-way seal container) with an increased seal as a natto production container, maintaining the integrity and taste of the natto product. Turned out to be possible.

  According to Table 12, the average weight change of Example 5 is 3.0, while the weight change of Comparative Example 4 is 4.5. That is, as the natto production container, the natto production container (three-way seal container) with the increased seal portion used in Example 1 is used to achieve a balance between the airtightness and the air permeability of the natto production container. It can be seen that the weight change can be reduced.

  Moreover, according to Table 13, the breaking strength of natto produced in Example 5 is substantially constant (average value 64.2-90.0) from 3 days to 44 days from the incorporation date, The breaking strength of the natto produced in Comparative Example 4 is (average value 70.3-80.2). Both have almost constant breaking strength.

  As mentioned above, according to an Example and a comparative example, after completion | finish of a fermentation process, the container for natto manufacture (three-way seal container) which increased the number of the sealing part is used as a container for natto manufacture which fills the cooled natto. Thus, it can be seen that the balance between airtightness and air permeability in the container can be maintained, and the natto quality (bitterness, stringing, generation of tyrosine, etc.) retention period (expiration date) can be extended. In addition, even if a normal natto container that does not increase the number of seals is used as a natto production container that is filled with cooled natto, the natto production container after heat treatment and cooling is used as a pillow. By packaging, the natto quality (bitterness, stringing, generation of tyrosine) retention period (expiration date) can be extended as described above. These results show that the natto product produced by the method for producing natto of the present invention has a shelf life of about 50 days at maximum by applying a simple technique. Considering that the quality retention period (expiration date) of natto products manufactured by the conventional natto manufacturing method is only about one week, the manufacturing method of the present invention has a period of 2 to 2 to maintain the quality of natto products. It can be improved about 7 times, and its technical significance is great.

  That is, according to the natto manufacturing method of the present invention, even when the demand at the time of ordering natto manufacturing and the demand at the time of shipment become inconsistent due to various conditions in the distribution process, natto that maintains a constant quality is always provided. Can do.

Natto production container 10
Housing recess 11
Container body 12
Lid 13
Convex part 14
Flange 15
Seal part 16
Lid 21
Container body 22
Flange 23
Seal part 24
Air hole 25

Claims (4)

Cooling the natto after completion of the fermentation process;
Wherein the cooling to process the via was natto been natto manufactured container a plurality of the above fermentation temperature natto filling temperature, a step of holding multi KaiKa heat,
A method for producing natto, comprising a step of cooling the container for producing natto that has undergone the heating and holding step. The container for producing natto has a container body in which a recess for storing natto is formed, a lid formed so as to cover the recess of the container body and having no air holes, and the container body A rectangular frame-shaped flange formed on the upper surface of the lid and a seal portion for bonding the lid body,
A convex part is formed inside the lid to be fitted to the container body,
The seal portion, the is adjusted so as to hold the airtightness and balance of breathable lid and said container body, method for manufacturing natto according to claim 1. Step, 15 minutes at a temperature T ₁ of the above fermentation temperature of natto, then said the heating holding at 5 to 15 ° C. lower temperature T ₂ 75 minutes than the temperatures T ₁ holding the multistage heating A method for producing natto according to claim 1 or 2 . Wherein after a multi-step heating holding step of cooling the natto manufactured container which has undergone a process of further pillow packaging the natto manufactured containers, according to claims 1, characterized in that a cooling storing step 3 The manufacturing method of natto of any one of Claims 1.