JP2023051878A - Production and preservation method and production apparatus of soybean curd - Google Patents

Abstract

To provide a production and preservation method of soybean curd that uses water from which dissolved gas is removed for soybean curd production and thus can suppress propagation of germs in a packaging vessel as low as possible and extend a consumption term without heat sterilization after including produced soybean curd in the packaging vessel.SOLUTION: The problem is solved by using water from which dissolved gas is removed for soybean curd production in all steps to use water for soybean curd production of an immersion step, a milling step, and cutting-out step and by filling the water in a packaging vessel and sealing the packaging vessel with the soybean curd immersed in the water.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a tofu manufacturing and preserving method and a manufacturing apparatus capable of setting a long expiration date without heat sterilization after enclosing tofu in a packaging container.

In general, tofu sold in shops and the like includes filled tofu, silken tofu, and firm tofu. Filled tofu is produced by cooling soybean milk obtained from soybeans, filling and enclosing it in a packaging container together with a coagulant, and heating and coagulating it. This filled tofu is heat sterilized because it is heated after it is enclosed in a packaging container, and has the advantage of being able to set a long expiration date.

On the other hand, silken tofu and cotton tofu are made by pouring soymilk obtained from soybeans into a mold and adding a coagulant inside the mold to coagulate it. sealed inside the packaging container. Such tofu that is not heated after being enclosed in a packaging container is called raw tofu, and is superior in flavor and texture to packed tofu. However, since it is not heated after it is enclosed in a packaging container, it has the drawbacks that the taste deteriorates quickly and the expiration date is shortened.

In view of these drawbacks, in order to extend the expiration date, a method of heat sterilization after encapsulation in a packaging container is generally practiced. This tofu is called boiled tofu, and although it has a long shelf life, there is a risk that the flavor of the tofu will escape into the enclosed water during heating, or that the texture of the tofu itself will deteriorate.

Therefore, as described in Patent Document 1, the produced tofu is immersed in deoxygenated water with dissolved oxygen of 1 mg / L or less, and dissolved in the water that is put together when sealed in the packaging container. A technique is disclosed in which the growth of aerobic bacteria is suppressed as much as possible without heat sterilization and the expiration date is extended by using deoxygenated water with an oxygen content of 1 mg/L or less.

JP 2019-83760

In the method for producing tofu described in Patent Document 1, the produced tofu is immersed in deoxygenated cooling water by a cooling device equipped with a deoxygenating device, and then the deoxygenated water and A method for enclosing tofu together inside a packaging container is described.

According to this method, the tofu is immersed in deoxygenated cooling water to replace the moisture contained in the tofu with the deoxygenated water, and the deoxygenated water and the tofu are placed in a packaging container. Enclosing them together reduces the amount of oxygen in the container, thereby extending the expiration date without heat sterilization.

However, it can be said that the method of Patent Document 1 is insufficient to reduce the amount of oxygen contained in tofu. In other words, the conventional method for producing tofu has many steps that may cause the tofu to contain oxygen. Therefore, it is difficult to say that the oxygen contained in the tofu can be completely replaced by immersing the tofu in deoxygenated water.
Furthermore, although the oxidation of tofu does not directly affect the expiration date, it causes the deterioration of the flavor. it is not possible.

The present invention has been made in view of the above circumstances, and water from which dissolved oxygen has been removed is used as tofu manufacturing water in all steps of tofu manufacturing, such as the soaking step, the grinding step, and the cutting step, which come into contact with water. At the same time, by filling the inside of the packaging container with tofu manufacturing water and enclosing the tofu in a state of being immersed in the packaging container, the amount of oxygen in the tofu enclosed in the packaging container is reduced, and the contact with oxygen is reduced. To provide a method for producing and preserving tofu that prevents oxidation.

Further, a water tank for storing water containing dissolved oxygen, a dissolved oxygen removing device for removing dissolved oxygen from the water stored in the water tank, and an amount of dissolved oxygen contained in the tofu manufacturing water generated by the dissolved oxygen removing device. Equipped with a dissolved oxygen measuring device that measures the soybean, a manufacturing water tank that stores the tofu manufacturing water, and a manufacturing water generating device that removes the dissolved oxygen contained in the water. To provide a soybean curd manufacturing apparatus capable of preventing oxidation in all processes.

The tofu manufacturing method and storage method according to the present invention, which have been made to solve the above problems, use water from which dissolved oxygen has been removed as tofu manufacturing water, and the soaking step, the grinding step, and the It is characterized by being used in all steps of the slicing process, filling the inside of the packaging container with water for producing tofu, and enclosing the tofu in a state in which the tofu is immersed.

Further, a tofu manufacturing apparatus according to the present invention, which has been made to solve the above problems, includes a water tank for storing water containing dissolved oxygen, and a dissolved oxygen removing device for removing dissolved oxygen from the water stored in the water tank. A manufacturing water generator comprising a device, a dissolved oxygen measuring device for measuring the amount of dissolved oxygen contained in the tofu manufacturing water generated by the dissolved oxygen removing device, and a manufacturing water tank for storing the tofu manufacturing water. It is characterized by

According to the method for producing and preserving tofu according to the present invention, water from which dissolved oxygen has been removed is used as tofu production water for producing tofu, and the tofu is immersed in the tofu production water and sealed in a packaging container. By reducing the amount of oxygen inside the tofu and the packaging container enclosing the tofu, the breeding of aerobic bacteria can be suppressed as much as possible, and the expiration date of the tofu can be extended without heat sterilization.

In addition, by using tofu manufacturing water from which dissolved oxygen has been removed as the water used in the manufacturing process, contact with oxygen during manufacturing can be reduced and oxidation can be prevented, and deterioration of the flavor of tofu can be prevented as much as possible. The flavor and texture can be preserved for a long time.

In addition, since it is possible to extend the expiration date without heat sterilization after enclosing tofu in the packaging container, the energy required for heat sterilization and the energy required for cooling after heating can be greatly reduced. It is also possible to reduce running costs.

According to the tofu manufacturing apparatus according to claim 2, water for manufacturing tofu is generated from which dissolved oxygen contained in the water is removed, and the water for manufacturing tofu is supplied to a device for processing soybeans and a device for packaging tofu. By manufacturing and packaging the tofu, it is possible to minimize the contact with oxygen during the manufacturing process, to produce tofu that can maintain the flavor and texture of the tofu for a long time, and to create an aerobic atmosphere inside the packaging container. It can suppress the growth of bacteria.

In addition, by measuring the amount of dissolved oxygen in the water for tofu manufacturing, which is generated by removing the dissolved oxygen contained in the water, it is possible to visually confirm that the dissolved oxygen has been reliably removed, and tofu manufacturing can contribute to reducing contact with oxygen in the

In addition, according to the tofu production and storage method and production apparatus described in claims 1 and 2, contact with oxygen is reduced from tofu production to storage to prevent oxidation of tofu and propagation of aerobic bacteria. and to provide a tofu manufacturing apparatus equipped with a dissolved oxygen removing device for removing dissolved oxygen and a dissolved oxygen measuring device for checking whether the dissolved oxygen is reliably removed in order to realize the above-described method. By doing so, it is possible to set a long expiration date without heat sterilization, and it is possible to obtain HACCP certification, which is established to ensure food safety.

As mentioned above, it is no longer necessary to heat sterilize the tofu packed in the packaging container, and it is possible to save energy in tofu production. It can contribute to "responsible consumption and production" and "concrete measures against climate change" related to the issue.

FIG. 2 is a flow diagram illustrating procedures of a method for producing tofu and a method for storing tofu according to one embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic explanatory diagram showing an overall image of a tofu manufacturing apparatus according to one embodiment of the present invention; 1 is a schematic explanatory diagram showing the configuration of a grinding device according to one embodiment of the present invention; FIG. FIG. 4 is a schematic explanatory diagram showing a conveying portion from a cutting device to a packaging device according to one embodiment of the present invention; FIG. 4 is a flow diagram illustrating procedures of a method for producing tofu and a method for storing tofu according to another embodiment.

The gist of the present invention is that water from which dissolved oxygen has been removed is used as tofu manufacturing water in all steps of contacting water related to tofu manufacturing, including the soaking process, the grinding process, and the cutting process, and the water for manufacturing tofu is contained in the packaging container. and to enclose the tofu in a immersed state.

Further, in the tofu manufacturing apparatus, a water tank for storing water containing dissolved oxygen, a dissolved oxygen removing device for removing dissolved oxygen from the water stored in the water tank, and tofu manufacturing water generated by the dissolved oxygen removing device It is also characterized by comprising a manufacturing water generator comprising a dissolved oxygen measuring device for measuring the amount of dissolved oxygen contained in the tofu, a manufacturing water tank for storing tofu manufacturing water, and a manufacturing water generating device.

[1. Method for producing and preserving tofu]
Hereinafter, one embodiment of the method for producing tofu and the method for preserving tofu according to the present invention will be described with reference to the accompanying drawings. The following embodiments are specific examples of the present invention, and do not limit the technical scope of the present invention. In addition, in the present embodiment, silken tofu is produced by solidifying and then cutting out, as an example, but firm tofu can be produced in the same manner by squeezing tofu.

FIG. 1 is a flow diagram illustrating procedures of a method for producing tofu from soybeans and a method for preserving tofu after production according to the present embodiment.

The method for producing and preserving tofu according to the present embodiment includes, as shown in steps 1 to 9 in FIG. 1, mainly a softening step S1 in which soybeans are soaked in water to soften them, and a draining step S2 in which water is removed from the softened soybeans. Then, a grinding step S3 in which the drained soybeans are ground while adding water, a heating step S4 in which the raw soybean paste obtained by grinding is boiled, and okara and soymilk are separated from the boiled soybean paste obtained by heating. a coagulating step S6 in which a coagulant is added to the extracted soymilk to solidify it; a cutting step S7 in which the tofu produced by coagulating the soymilk is immersed in water and cut; and the cut tofu is packaged. It consists of a sealing step S8 of sealing in a container and a cooling step S9 of cooling the tofu sealed in the packaging container to a temperature suitable for storage.

Hereinafter, steps 1 to 9 of the method for producing and storing tofu according to the present embodiment will be specifically described. Also, the tofu manufacturing water SW used in the method for manufacturing and preserving tofu according to the present embodiment is water from which dissolved oxygen has been removed. As a method for removing dissolved oxygen when producing the tofu manufacturing water SW, the dissolved oxygen in the water is replaced with an inert gas such as nitrogen or argon. Also, a bubbling method of sending an inert gas into water may be used, but a method of filling an inert gas in a sealed container and passing water through it to replace dissolved oxygen with the inert gas is preferable.

The softening step S1, which is step 1, is a step of immersing soybeans in tofu manufacturing water SW to soften them by soaking them with water. Specifically, a tank for soaking soybeans is filled with tofu manufacturing water SW, and soybeans are soaked therein. The time it takes to soak the soybeans varies depending on how long it has been since the soybeans have been harvested and the climate. .

At this time, if water containing a large amount of dissolved oxygen is used as in the softening process of the conventional manufacturing method, the enzymes (soybean protein) contained in the soybeans are activated and oxidized. However, by using the tofu manufacturing water SW produced by removing dissolved oxygen in the softening step S1, the activity of enzymes (soybean proteins) contained in soybeans can be suppressed as much as possible and oxidation can be prevented.

In addition, this softening step S1 is performed in a soybean soaking tank filled with tofu manufacturing water SW to prevent oxygen from dissolving in the tofu manufacturing water SW. you can go In this case, to prevent oxygen from dissolving in the tofu manufacturing water SW in the water tank, the tofu manufacturing water SW is periodically replaced with new tofu manufacturing water SW, or an inert gas such as nitrogen is injected to further oxidize the water. can be prevented.

In particular, it is preferable to continuously pour the tofu manufacturing water SW from the lower part of the water tank in which the soybeans are soaked so that the tofu manufacturing water SW spills out of the water tank. That is, the tofu-making water SW in the water tank can be always kept fresh by continuously pouring the tofu-making water SW from the lower part of the water tank, which is not exposed to air, and causing the water tank to overflow. Therefore, in the softening step S1, which is step 1, it is possible to prevent contact between soybeans and oxygen. Also, before the softening step S1, the skin of the soybean immersed in the tofu manufacturing water SW may be peeled off.

The draining step S2, which is Step 2, is a step of removing water adhering to the surface of the soybeans softened by the tofu manufacturing water SW. The tofu manufacturing water SW that adheres to the soybeans is water from which dissolved oxygen has been removed, but since the water from which the dissolved oxygen has been removed has the property of easily dissolving gas when stimulated, it adheres to the soybeans taken out from the tofu manufacturing water SW. It is necessary to reliably remove excess water, ie excess water. Therefore, in the draining step S2 of step 2, the softened soybeans are taken out from the tofu manufacturing water SW and drained reliably using a centrifugal separator. By reliably removing the surplus water adhering to the soybeans in this manner, oxidation of the soybeans can be suppressed as much as possible.

The water adhering to the surface of the soybeans that have undergone this draining step S2 is surely removed, and the internal water content is reduced to about 30 to 40%. In addition, although the centrifugal separator is used to drain the water in this embodiment, any method of draining the water can be used as long as the surplus water can be reliably removed. Any method such as a method or a method of wiping the surface with a dry cloth may be used.

The grinding step S3, which is Step 3, is a step of grinding the soybeans after draining the water while adding water. Through this process, the soybean milk and soybean curd lees called raw soybean paste are made. Tofu manufacturing water SW from which dissolved oxygen has been removed is used for water addition in this grinding step S3. That is, when soybeans are pulverized, the water added so that the soybean protein is not activated or thermally denatured by frictional heat is water for producing tofu SW from which dissolved oxygen has been removed. can be suppressed.

As a specific method of the grinding step S3, the soybeans from which surplus water has been sufficiently removed in the draining step S2 are dropped into a grinder for grinding soybeans, and water SW for producing tofu is added. This addition of water is performed so that the soybean protein contained in the soybean is not thermally denatured by the frictional heat of the blade of the grinder. Moreover, although a grinder is used as a means for pulverizing soybeans in the grinding step S3, any means may be used as long as the soybeans can be finely pulverized. If the skins of soybeans are not removed before the softening step S1, they are pulverized together with the seeds in the pulverizing step S3.

The heating step S4, which is step 4, is a step of thermally denaturing the soybean protein by heating the raw soybean paste obtained in the grinding step S3. Specifically, the raw go obtained in the grinding step S3 is boiled at a temperature of 80°C to 100°C. At this time, since the water contained in the raw soybean paste is the tofu manufacturing water SW added in the grinding step S3 of step 3, the raw soybean paste can be boiled without being oxidized. Also, during boiling of raw soybean paste, bubbles are generated due to the surfactant effect of soybean saponin contained in soybeans. When the tofu is boiled in water containing a large amount of dissolved oxygen, as in the ordinary method of producing tofu, a large amount of bubbles are generated by combining with the oxygen contained in the water.

However, since the raw soybean soup according to the present embodiment contains a small amount of oxygen as a result of the above-described method, it is possible to minimize the generation of foam due to soybean saponin. When a large amount of foam is generated during boiling due to this saponin, there is a risk that the tofu will be overcooked, and if the tofu is processed into tofu with the foam remaining, the texture will be poor. Therefore, it is necessary to add an antifoaming agent to eliminate the foam. Antifoaming agents do not harm the body when eaten by humans, but they reduce the flavor and eliminate soybean saponin. However, in this embodiment, the amount of defoaming agent added can be minimized because less foam is generated.

In this heating step S4, the soybean protein is thermally denatured into a state called boiled go, the boiled go is separated into bean curd refuse and soy milk, and a coagulant is added to the obtained soy milk in the coagulating step S6 described later. It can be made into tofu. As a method for heating the raw soybean soup in the heating step S4, any method can be used as long as it can heat the raw soybean soup at 80° C. to 100° C. For example, autoclave treatment is possible. By using the heating method, the inside of the pot becomes a high-temperature and high-pressure state by the generated saturated steam, and a sterilization effect can be obtained.

The extraction step S5, which is step 5, is a step of separating the boiled go obtained in the heating step S4 into soymilk and okara. As a specific separation method, the boiled soybean paste obtained in the heating step S4 is filtered through a mesh to separate soymilk and bean curd refuse. In addition, a method using a mesh is used as a method for separating the soymilk and okara, but any method may be used as long as the soymilk and okara can be separated. It may be squeezed or squeezed by a screw type squeezer.

The coagulation step S6, which is step 6, is a step of adding a coagulant to the soymilk obtained in the extraction step S5 to coagulate the soymilk. Specifically, the soymilk extracted in the extraction step S5 is poured into a stainless steel mold and a coagulant is added. The soymilk is reliably coagulated by the coagulant by heating the soybean soybean protein in the heating step S4, which is the preceding step of the extraction step S5.

The coagulant used here may be a method using a metal salt such as magnesium chloride (bittern) or calcium sulfate, or a method using gluconodeltalactone or arrowroot powder. A mixture of a plurality of coagulants, such as a mixture of potassium chloride and magnesium sulfate, may also be used. Also, this coagulant is normally in the form of a powder, and when it is put into the soymilk, it is preferably put into the soymilk as a coagulating liquid made by dissolving it in the tofu manufacturing water SW. A coagulant is added to the soymilk poured into the mold, and the soymilk is completely solidified in about 10 to 30 minutes to produce tofu.

As described above, soybeans are not exposed to oxygen more than necessary until the processing of soybeans into tofu is completed. It is possible to produce high-quality tofu that retains the original taste of soybeans by preventing oxidation of soybeans during the production process.

The cutting step S7 of step 7 is a step of immersing the tofu produced in the above-described method of producing tofu in a water tank filled with water and cutting the tofu. Specifically, a water tank is filled with tofu manufacturing water SW from which dissolved oxygen has been removed, and the tofu produced by coagulating soy milk in the coagulation step S6 is taken out of the mold and immersed in the water tank. The soaked tofu is cut into pieces according to the size of the packaging container while being exposed to water in a water tank. Furthermore, the tofu cut in the water tank is stored in a packaging container with an upper opening inside the same water tank.

In the slicing step S7, slicing the tofu while immersing it in a water tank filled with tofu manufacturing water SW from which dissolved oxygen has been removed prevents oxidation of the tofu without coming into contact with oxygen. Furthermore, by storing the tofu in the packaging container inside the water tank, the tofu manufacturing water SW is stored in the storage container together with the tofu. can be prevented from coming into contact with As in the softening step S1 of step 1, the tofu-making water SW is periodically replaced with new tofu-making water SW or filled with an inert gas such as nitrogen so that gas does not dissolve in the tofu-making water SW. can be injected to further prevent oxidation.

In particular, in this embodiment, the water SW for making tofu is continuously poured from the bottom of the water tank in which the soybeans are soaked so that the water SW for making tofu is spilled from the water tank. That is, the tofu-making water SW is continuously supplied from the lower part of the water tank, which is not exposed to air, and the water tank is overflowed so that the tofu-making water SW in the water tank is always fresh. By doing so, in the cutting step S7, which is step 7, the tofu is cut into a predetermined size while being constantly in contact with the tofu manufacturing water SW from which dissolved oxygen has been removed, thereby preventing the tofu from coming into contact with oxygen. can be made

The enclosing step S8, which is step 8, is a step of hermetically enclosing the upper opening of the packaging container containing the tofu cut out in the cutting out step S7. At this time, before the top opening is covered, new tofu manufacturing water SW is introduced from the top opening of the packaging container to replace the tofu manufacturing water SW that was originally stored inside the packaging container. By doing so, the tofu is always immersed in the tofu manufacturing water SW from which dissolved oxygen has been removed at the time of sale or storage. It is possible to reduce the amount and suppress the growth of aerobic bacteria.

Specifically, the tofu stored together with the tofu manufacturing water SW in a container with an upper opening is conveyed by the conveyor C to the packaging device 320 that closes the opening of the container. At this time, the water SW for making tofu is exposed to air from the upper opening of the container until the opening is closed by the packaging device 320 . That is, there is a possibility that oxygen will dissolve in the tofu manufacturing water SW in the container during this time.

Therefore, in the present embodiment, as shown in FIG. 4, a plurality of tofu manufacturing water supply units 321 are provided between a water tank containing tofu in the container and the packaging device 320 for flowing the tofu manufacturing water SW into the container. ing. That is, by pouring new tofu manufacturing water SW into the container during transportation and transporting while replacing the old tofu manufacturing water SW originally stored in the container, the tofu manufacturing water SW in the container during transportation is transferred. of oxygen can be prevented.

The cooling step S9, which is step 9, is a step of lowering the packaging container containing the tofu and the tofu manufacturing water SW in the enclosing step S8 to a temperature suitable for storage.
This cooling step S9 is performed in the same manner as the boil-cool step performed in the conventional tofu manufacturing method. That is, the packaging container enclosing the tofu and the tofu manufacturing water SW is cooled to about 5° C. by the cooling water in the cooling tank. However, since the heat sterilization treatment (boiling treatment) in the conventional manufacturing process is not performed, the temperature of the tofu before cooling is lower than before, which greatly shortens the time required for cooling. can.

In addition, in the above-described embodiment, the process of producing silken tofu is described, but when producing firm tofu, in addition to producing by the same process as the above-mentioned method for producing silken tofu, coagulation There is a process of wrapping the tofu with a cloth and applying pressure to remove the moisture inside. The cloth used in this step is preferably moistened with tofu manufacturing water SW before the tofu is wrapped and covered. By doing so, the amount of oxygen contained in the contacting water is less than that moistened with plain water, so the increase of aerobic bacteria can be further suppressed.

[2. About measurement results of general live sterilization]
Next, the setting of the expiration date of tofu produced by the method for producing and preserving tofu according to the present embodiment will be described. Generally, the expiry date of tofu is set about two days before the day when the number of general bacteria reaches 100,000/g. Therefore, the inventor conducted the following experiment and set the expiration date of silken tofu produced by the method of producing tofu according to the present embodiment to 10 to 12 days, which is the same as that of general boiled tofu.

As for the content of the experiment, 10 silken tofu produced on the same day were randomly selected for the experiment. The 10 silken tofu were opened 5 times on the 6th, 13th, 16th, 19th and 22nd days from the date of manufacture, and two of each were opened, and the number of general bacteria was counted. At this time, the reason why it is set to 6 days from the production date is that the set date of the general expiration date for raw tofu, which is unheated tofu, like the silken tofu produced by the method for producing tofu according to the present embodiment. according to. In addition, the reason why 10 silken tofu were randomly selected from a large amount of silken tofu produced on the same day is that, as with food inspections in general, if the production timing is exactly the same, the overall production process will be improved. This is because it is difficult to examine safety. The results of the above experiments are shown in Table 1 below.

As shown in Table 1, the silken tofu stored for up to 22 days had the highest number of general bacteria of 20,000/g. Therefore, the value of common bacteria is far below the standard of 100,000/g. Therefore, it was proved that there is no problem in setting the expiration date of this silken tofu to 10 to 12 days, which is the general expiration date of boiled tofu, which is heat-treated after the tofu is sealed in a container.

That is, the silken tofu produced by the method for producing tofu according to the present embodiment is not subjected to heat sterilization after encapsulation in a container, so that it has the rich flavor of soybeans unique to raw tofu and heat sterilization. It is possible to set a longer expiry date than the same as boiled tofu.

In addition, the inventor conducted an experiment to investigate the general bacterial count not only of silken tofu but also of firm tofu produced by the method for producing tofu according to the above-described embodiment. As for the conditions, 10 test subjects were randomly selected from the cotton tofu produced on the same day in the same manner as the silken tofu. The 10 pieces of firm tofu were divided into 5 times, 6 days, 13 days, 16 days, 19 days and 22 days from the date of manufacture, and two of each were opened and the number of general bacteria was counted. The results of the above experiments are shown in Table 2 below.

As shown in Table 2, the highest number of common bacteria in the cotton tofu stored for up to 22 days was 24000/g. Therefore, the cotton tofu produced by the method for producing tofu according to the present embodiment has a general bacteria value much lower than the standard of 100,000 bacteria/g, similarly to the silken tofu. It was proved that there is no problem in setting the expiration date of 10 to 12 days, which is the general expiration date of boiled tofu that is heat-treated after being enclosed in the tofu.

From these experimental results, in the production of tofu, by using tofu production water SW from which dissolved oxygen has been removed in the process of contacting with water, and by using a method of preventing oxygen contamination, the soybean flavor is rich and excellent. It was proved that it is possible to store raw tofu with a good taste for a long period of time.

[3. Comparison of energy consumption related to tofu production and storage methods]
Next, the amount of energy involved in the production of tofu is compared with the conventional production method. The amount of energy described here is the use of gas for heating, the use of electricity for cooling, and the like, and is expressed in units of calories (kcal). In addition, a case where silken tofu is produced in an environment with an outside temperature of 25° C. will be compared as an example.

The total calorie count of tofu produced by the conventional method is about 102 kcal per block of tofu. The breakdown is that the number of calories required in the heating step S4 for heating the raw soybean paste obtained in the above grinding step S3 is about 32 kcal per tofu (25°C raw soybean paste is heated by 75°C to 100°C). case), the number of calories required for the coagulation step S6 of coagulating the soymilk and the cutting step S7 of immersing the tofu in water and cutting it is about 22 kcal per tofu (from adding the coagulant to the boiled go at 100°C to cutting). When the temperature of the tofu reaches 45°C by removing the heat of 55°C in the water tank), the number of calories required in the boiling process of heating and sterilizing the tofu after enclosing it in a packaging container is about 16 kcal (the temperature reached 45°C in the slicing process. When the temperature of the tofu is raised by 40°C to 85°C), the number of calories required for the cooling process to lower the tofu sterilized in the boiling process to the storage temperature is about 32 kcal (the tofu that has reached 85°C in the boiling process). is lowered by 80°C to a storage temperature of 5°C).

When tofu is produced by the method for producing and preserving tofu according to the present embodiment, as described above, it is not necessary to perform heat sterilization after sealing the tofu in the packaging container, and the number of calories required for the boiling process is reduced. Since no further heating is performed, the number of calories consumed in the cooling step S9, in which calories are finally consumed, can be suppressed.

Therefore, the total number of calories required for producing tofu from soybeans, enclosing the produced tofu in a packaging container, and preserving it is about 70 kcal.

The breakdown is that the number of calories required in the heating step S4 for heating the raw soybean paste obtained in the above grinding step S3 is about 32 kcal per tofu (25°C raw soybean paste is heated by 75°C to 100°C). case), the number of calories required for the coagulation step S6 of coagulating the soymilk and the cutting step S7 of immersing the tofu in water and cutting it is about 22 kcal per tofu (from adding the coagulant to the boiled go at 100°C to cutting). When the heat of 55°C is taken away in the water tank and the temperature of the tofu reaches 45°C), the number of calories required to seal it in the packaging container after the cutting step S7 and lower it to the storage temperature is about 16 kcal (45 kcal after the cutting step S7). ℃, is lowered by 40 ℃ to 5 ℃), and the total is 70 kcal.

As described above, the tofu manufactured using the tofu manufacturing water SW from which dissolved oxygen has been removed at the time of sale or storage is enclosed in a packaging container together with the tofu manufacturing water SW, thereby reducing the amount of oxygen in the packaging container. and prevent the growth of aerobic bacteria. That is, it is possible to suppress the propagation of bacteria as much as possible and extend the expiration date without performing heat sterilization after sealing the tofu in the packaging container. In addition, by extending the expiration date of tofu without heat sterilization, it is possible to meet the "responsible consumption and production" and "responsibility to produce" and "responsible consumption" stipulated in the Sustainable Development Goals (SDGs) as a countermeasure against food loss and environmental problems caused by energy consumption. Concrete action on climate change can contribute.

[4. About manufacturing equipment]
Next, a tofu manufacturing apparatus for realizing the above-described method for manufacturing and storing tofu will be described with reference to the drawings. FIG. 2 is a schematic diagram for explaining the configuration necessary for the tofu manufacturing apparatus M according to the present embodiment and the connection points of the supply pumps for supplying the tofu manufacturing water SW.

As shown in FIG. 2, the tofu manufacturing apparatus M includes a manufacturing water generating apparatus 100 that generates tofu manufacturing water SW mainly by removing dissolved oxygen contained in water, and a soybean processing apparatus that processes soybeans to tofu. It is composed of a device 200 and a packaging and cooling device 300 for packaging the manufactured tofu.

The production water generation apparatus 100 includes a water tank 110 that stores water W supplied from a water supply unit 400, a dissolved oxygen removal device 120 that removes dissolved oxygen contained in the water W stored in the water tank 110, a dissolved oxygen measuring device 130 for measuring the amount of dissolved oxygen contained in the tofu, and a manufacturing water tank 140 for storing water (tofu manufacturing water SW) from which dissolved oxygen has been removed.

The water supply unit 400 may be of any type as long as it can supply water W that can be used for tofu production, such as a well or water supply. Also, the water tank 110 may be of any type as long as it can store the water W supplied from the water supply unit 400 .

The dissolved oxygen removal device 120 is a device that removes dissolved oxygen contained in water by allowing the water W stored in the water tank 110 to pass through it. Specifically, the low-pressure sealed container is filled with nitrogen gas, and by allowing water W to pass through it, the dissolved oxygen contained in the water can be replaced with nitrogen gas. The dissolved oxygen contained in the water is replaced with nitrogen, and the above-mentioned tofu manufacturing water SW is used for processing soybeans and preserving tofu.

Further, in the present embodiment, a method of removing dissolved oxygen from the water W passing through by filling the low-pressure sealed container with nitrogen gas is used. Any method or apparatus may be used, for example, a bubbling method in which an inert gas is dissolved in water W may be used. In addition, although nitrogen is used as the gas to be replaced in this embodiment, any inert gas may be used, for example, argon gas may be used instead of nitrogen.

The dissolved oxygen measuring device 130 is for measuring the amount of dissolved oxygen contained in the tofu manufacturing water SW generated by the dissolved oxygen removing device 120 . As a method for measuring the amount of dissolved oxygen, a method using a diaphragm electrode, a method using a fluorescent sensor that irradiates a blue LED, or the like may be used.

A value of less than 2 mg/L is preferable as the tofu manufacturing water SW for processing soybeans and preserving tofu. Therefore, the dissolved oxygen measuring device 130 measures the amount of dissolved oxygen, and if it exceeds the reference value of 2 mg/L, the dissolved oxygen is removed by passing it through the dissolved oxygen removal device 120 again, and if the value is less than the reference value. If so, it is carried to the next manufacturing water tank 140 .

The manufacturing water tank 140 is for storing the tofu manufacturing water SW which is generated by the dissolved oxygen removing device 120 and whose dissolved oxygen content is confirmed to be less than the reference value of 2 mg/L by the dissolved oxygen measuring device 130. be. This manufacturing water tank 140 may have any shape as long as it can store the tofu manufacturing water SW. It may dissolve in water.

Therefore, an input pipe for inputting the tofu manufacturing water SW is provided below the tank main body. By doing this, the falling distance of the tofu manufacturing water SW that is put into the inside of the manufacturing water tank is shortened, the stimulus is minimized, and the discharge port of the input pipe becomes below the water surface immediately after the start of charging, and the air It is possible to minimize contact with the water and prevent oxygen from re-dissolving into the water.

As shown in FIG. 2, the manufacturing water tank 140 is connected to a supply pump 143, which supplies the tofu manufacturing water SW to the soaking tank 210, the grinding device 230, the tofu cutting device 310, and the packaging device 320, which will be described later. is configured to

In addition, a pump may be provided for transporting the water W and the tofu manufacturing water SW between the devices of the manufacturing water generating device 100 as necessary depending on the installation conditions of the devices. For example, in a large facility, the water tank 110 may be installed on the roof of the facility, and a pump is required to supply the water W to the dissolved oxygen removal device 120 installed inside the facility. can be considered.

The soybean processing apparatus 200 includes a soaking tank 210 for soaking soybeans, a draining device 220 for draining the soaked soybeans, a grinding device 230 for grinding the drained soybeans to produce raw soybean soup, and heating the raw soybeans. It is composed of a heating device 240 for making boiled soybean paste, an extracting device 250 for separating the boiled soybean paste into soybean milk and bean curd refuse, and a coagulation frame 260 for solidifying the soybean milk.

The immersion tank 210 is for performing the softening step S1 of the tofu manufacturing method described above. Specifically, whole soybeans, which are raw materials for tofu, are soaked with water to soften them. At this time, the tofu manufacturing water SW supplied by the supply pump 143 is used as the water filled inside the soaking tank 210 . By doing so, the soybeans can be softened by absorbing moisture while preventing the soybeans from being oxidized.

The draining device 220 is for performing the draining step S2 of the tofu manufacturing method described above. Specifically, it is a device for removing surplus water adhering to the surface of soaked and softened soybeans, and uses, for example, a centrifugal separator.

The grinding device 230 is for performing the grinding step S3 of the tofu manufacturing method described above. Specifically, as shown in FIG. 3, a grinding unit 231 for grinding soybeans and a raw soybean soup receiving unit 232 disposed below the grinding unit 231 and receiving raw soybeans obtained by grinding the soybeans. and a supply pipe 233 for supplying tofu manufacturing water SW, and for example, a grinder is used. The supply pipe 233 is connected at its base end to the supply pump 143 and is bifurcated at its end so that the tofu manufacturing water SW can be supplied to the grinding section 231 and the raw bean curd receiving section 232, respectively.

When grinding soybeans, it is necessary to add water so that the soybean protein is not thermally denatured by frictional heat generated between the apparatus and the soybeans. Therefore, the grinding device 230 is connected to the supply pump 143 described above, and performs the grinding operation while supplying water with the tofu manufacturing water SW.

By the way, a value called Brix is important for the production of tofu. Brix is a value measured by a Brix meter, and it indicates how much solid ingredients are contained in raw soybean paste, soymilk, etc. If this value is too low, solid ingredients (soybean protein) and moisture and separate. If the coagulant is added in that state, the water content of the coagulated product is low and the product called silken tofu cannot be obtained.

Therefore, it is necessary to adjust the ratio of Brix to the whole so that the Brix value is 12% or more of the whole when making silken tofu, and 7% or more of the whole when making cotton tofu. . Therefore, in the conventional production of tofu, adjustment was made by adding water during the grinding operation so as to achieve the above values (12% or more for silken tofu and 7% or more for cotton tofu). However, when a grinder is used as the grinding device 230, the water added together with the soybeans is also greatly agitated during grinding, and even the tofu manufacturing water SW from which the dissolved oxygen has been removed is stimulated by the stirring. Oxygen may redissolve.

Therefore, during the grinding operation performed by this grinding device 230, the minimum amount of tofu manufacturing water SW that prevents frictional heat generated during grinding is supplied directly to the grinding section 231 from the upper supply pipe 233 shown in FIG. . Then, the feed provided in the lower part shown in FIG. Next, the tofu manufacturing water SW is supplied from the pipe 233 to the raw soybean paste receiving portion 232 for adjustment. By adopting such a method, the unavoidable dissolution of oxygen during milling can be minimized.

The heating device 240 is for performing the heating step S4 of the tofu manufacturing method described above. Specifically, the soybean protein contained in the soybeans is thermally denatured by heating the raw soybean paste obtained by grinding with the grinding device S3, and the soybean paste is brought into a state called boiled soybean paste. The heating device 240 may be any device as long as it can heat the raw soybean soup at 80° C. to 100° C. For example, it may be a method of transferring heat directly to the boiling pot. However, by using a device that enables autoclave treatment using a boiler, etc., the heating state becomes a high temperature and high pressure state, and in addition to the sterilization effect, the inside of the device becomes a low oxygen state, which further suppresses oxidation. It is more preferable because it can be done.

The extraction device 250 is for performing the extraction step S5 of the tofu manufacturing method described above. Specifically, the boiled soybean paste in which the soybean protein has been denatured by the heating device 240 is separated into soymilk and bean curd refuse. Any device can be used as long as it can separate the liquid portion and the solid portion of boiled soybean paste. It is recommended to use a squeezing machine or a strainer that separates boiled go through a mesh.

The coagulation frame 260 is for performing the coagulation step S6 of the tofu manufacturing method described above. Specifically, it is composed of a rectangular stainless steel frame, and the soymilk obtained from the extraction device 250 is poured into the frame and a coagulating solution is added to coagulate the soymilk to produce tofu. The coagulation solution is a mixture of multiple coagulants, such as a method using metal salts such as magnesium chloride (bitter) or calcium sulfate, a method using glucono delta lactone or arrowroot powder, or a mixture of potassium chloride and magnesium sulfate. However, the one using tofu manufacturing water SW as a solvent for turning the powdery coagulant into a coagulating liquid is used. By doing so, it is possible to prevent the tofu from being oxidized due to the moisture contained in the coagulation liquid. By putting the soymilk and the coagulating liquid into the coagulating frame 260, coagulation is completed in about 10 to 30 minutes, and tofu can be obtained.

The packaging cooling device 300 includes a cutting device 310 for cutting the manufactured tofu into a predetermined size, a packaging device 320 for sealing the cut tofu in a packaging container, and a packaging device suitable for storage by removing residual heat from the packaged tofu. a cooling device 330 for cooling to temperature.

The cutting device 310 is for performing the cutting step S7 of the tofu manufacturing method described above. Specifically, it consists of a water tank for taking out the tofu formed in the coagulation frame 260 in water, a cutting part provided in the water tank, and a packing container input part, and an operator guides the tofu to the cutting part. Tofu is automatically cut out according to the size of the packaging container, and the tofu is put in water in the packaging container with the upper opening set in the packaging container insertion part. A device called an underwater cutting machine or a cut caser may be used. It is also conceivable that only a water tank is provided, and that the cutting of tofu and the packing of the tofu into packaging containers are performed manually by craftsmen.

The water tank provided in the cutting device 310 uses tofu manufacturing water SW supplied from a connected supply pump 143 as shown in FIG. 2 instead of normal water W. By filling the inside of the water tank with the water SW for producing tofu, contact with oxygen is cut off when the tofu is cut out, so that the inside of the tofu does not contain oxygen and oxidation can be prevented as much as possible. Further, since the tofu is stored in water in the packaging container with the top opening, contact with oxygen can be cut off even during the storing operation, and the tofu manufacturing water SW can be mixed with the tofu in the packaging container with the top opening. Since the tofu is stored together, it is possible to prevent the tofu from coming into direct contact with oxygen even during transportation to the next packaging device 320 .

In addition, since the water tank is connected to the water tank 140 and the supply pump 143, the tofu manufacturing water SW in the water tank can be smoothly replaced with new tofu manufacturing water SW at regular intervals. Tofu manufacturing water SW with a dissolved oxygen content of less than 2 mg/L can always be filled in a water tank.

Also, most preferably, a supply port for the tofu-making water SW is provided at a lower position of the water tank so that the tofu-making water SW is supplied without coming into contact with the air, and the old tofu-making water SW is continuously supplied from the upper part of the water tank. should be kept in an overflowed state. By doing so, the tofu manufacturing water SW in the water tank can always be kept fresh, and contamination with oxygen over time can be prevented as much as possible.

The packaging device 320 is for performing the enclosing step S8 of the tofu manufacturing method described above. Specifically, the cutting device 310 closes the upper opening of the packaging container in which the tofu is stored and encloses it in a sealed state. In addition, during transportation to the packaging device 320 for enclosing the lid, as shown in FIG. A supply port is provided for supplying.

More specifically, a plurality of tofu manufacturing water supply units 321 are provided above the conveyor C used for transportation from the water tank where the tofu is cut to the packaging device 320 that closes the opening of the container. By doing so, it is possible to carry in the tofu while constantly replacing the tofu manufacturing water SW in the container for storing the tofu being carried in with a new one. Therefore, it is possible to prevent oxygen from being mixed into the tofu-making water SW stored in the container together with the tofu while the tofu is being conveyed by the conveyor C.

That is, in the packaging container containing the tofu by the cutting device 310, the tofu manufacturing water SW stored together with the tofu by the cutting device 310 is replaced with a new one by the tofu manufacturing water SW supplied from the supply port, After that, the packaging device 320 seals the upper opening and encloses it. Even if oxygen dissolves again in the inside of the tofu manufacturing water SW originally stored together during transportation from the cutting device 310 to the packaging device 320, the tofu manufacturing water SW is replaced with new tofu manufacturing water SW before encapsulation, so that the tofu is reliably enclosed. It can prevent later oxidation of tofu. In addition, by enclosing tofu in the packaging container together with tofu manufacturing water SW having a dissolved oxygen content of less than 2 mg / L, the propagation of aerobic bacteria inside the packaging container is prevented, and after enclosing in the packaging container as described above, The shelf life of tofu can be extended to about two weeks without heat sterilization.

In the conventional manufacturing method, there is a manufacturing method in which the tofu is cut out in accordance with the packaging container and then exposed to water for cooling for a while. Seal the packaging container immediately. By doing so, the possibility of the tofu coming into contact with oxygen can be minimized, and oxidation can be reliably prevented and oxygen can be prevented from entering the packaging container.

The cooling device 330 is for performing the cooling step S9 of the tofu manufacturing method described above. The tofu sealed inside the packaging container by the packaging device 320 retains the heat generated by the manufacturing process up to that point, that is, the residual heat, and if it is shipped as it is, it may be damaged by the heat. . Therefore, as in the conventional manufacturing method, the remaining heat is removed by immersing it in a water tank filled with cooling water, and the temperature is cooled to a temperature suitable for storage.

Specifically, as shown in the energy consumption related to the tofu production and storage method described above, the temperature of the tofu after the cutting step S7 is about 45 ° C., and it is packaged to a temperature of about 5 ° C. to 10 ° C. suitable for storage. Soak the whole container in cooling water to remove residual heat. In addition, conventionally, in order to sterilize silken tofu and cotton tofu, it was necessary to perform heat sterilization treatment (boiling treatment) after sealing in the packaging container, so the temperature after boiling was about 85 ° C. to about 5 ° C., which is suitable for storage. Cool to ~10°C. Therefore, the tofu manufacturing apparatus M and the method for manufacturing and storing tofu according to the present embodiment have the effect of shortening the time required for cooling.

As described above, in the tofu manufacturing apparatus M according to the present invention, the dissolved oxygen removing device 120 for removing dissolved oxygen and the tofu manufacturing water SW generated by removing the dissolved oxygen by the dissolved oxygen removing device 120 is 2 mg, which is the reference value. /L, and a supply pump 143 supplies the generated tofu manufacturing water SW to the soybean processing device 200 and the packaging cooling device 300, thereby oxidizing the tofu during manufacturing. It is possible to suppress the propagation of aerobic bacteria during storage and extend the expiration date without heat sterilization.

In addition, this tofu manufacturing and preserving method that has succeeded in extending the expiration date by removing dissolved oxygen in this way, and a device for removing dissolved oxygen and its removal by the tofu manufacturing apparatus M in order to realize this tofu survival and preserving method. HACCP approval can be obtained by providing a device that can visually confirm the

Moreover, the soybean processing apparatus 200 and the packaging/cooling apparatus 300 may be equipped with dewatering devices for removing water by blowing air. By doing so, it is possible to remove the water adhering to each device and the transport route, thereby preventing erroneous contamination of water containing dissolved oxygen.

[4. Other Examples]
Hereinafter, other embodiments of the method for producing tofu and the method for preserving tofu according to the present invention will be described with reference to the accompanying drawings. FIG. 5 is a flow diagram illustrating procedures of a tofu manufacturing method and a storage method according to another embodiment.

As another embodiment, it is conceivable to drain the soybeans softened in the softening step S1, crush the drained soybeans, and steam the soybeans for heating.

A method for producing tofu according to another embodiment includes, as shown in steps 1 to 5 of FIG. A soybean pulverization step S2′, a soybean protein denaturation step S3′ in which the pulverized soybeans are steamed and heated, an extraction step S4′ in which the steamed soybeans are separated from bean curd refuse and soymilk, and a coagulant is added to the extracted soymilk. and a coagulation step S5'.

Hereinafter, steps 1 to 5 of the method for producing tofu according to the present embodiment will be specifically described. The tofu manufacturing water SW used in the tofu manufacturing method and storage method described below is water from which dissolved oxygen has been removed. The method for removing the dissolved gas when producing the tofu manufacturing water SW is not particularly limited, and it may be produced by, for example, a membrane degassing method, a replacement method with an inert gas, a depressurization method, or the like. .

The softening step S1', which is Step 1, is a step of immersing soybeans in tofu manufacturing water SW to absorb moisture and soften the soybeans. At this time, by using tofu manufacturing water SW produced by removing dissolved oxygen as the water used for soaking, the soybeans can finish the softening step S1 without coming into contact with oxygen during soaking and without being oxidized. In order to prevent gas from dissolving into the tofu manufacturing water SW during this softening step S1′, the tofu manufacturing water SW is periodically replaced with new tofu manufacturing water SW or an inert gas such as nitrogen is injected to further oxidize the tofu manufacturing water SW. can be prevented.

The soybean crushing step S2', which is step 2, consists of a draining step S2'-1 for draining the soybeans and a crushing step S2'-2 for crushing the drained soybeans.

The draining step S2'-1 is a step of taking out the soybeans softened by the softening step S1' containing moisture inside from the tofu manufacturing water SW and removing excess water adhering to the surface. If the surplus water adhering to the surface is not sufficiently removed, the tofu manufacturing water SW produced by removing the dissolved gas will continue to come into contact with air, resulting in oxygen-containing water that will mix with the soybeans. There is fear. Therefore, the draining step S2'-1 reliably removes excess water adhering to the surface of the soybeans, thereby preventing oxidation of the soybeans.

As a specific method of draining water, any method such as a method using a rag or a method of wiping the surface with a dry cloth may be used. Alternatively, water may be drained using a centrifugal separator.
In this draining step S2'-1, it is desirable to set the water content in the soybeans to about 30 to 40%.

The pulverizing step S2'-2 is a step of pulverizing the soybeans, from which excess water has been sufficiently drained in the draining step S2'-1, using a grinder. By finely pulverizing the soybeans in this step, there is an effect of facilitating the extraction of soymilk in the extraction step S4' described later. Further, although the grinder is used as a means for pulverizing soybeans in the pulverizing step S2'-2, any means may be used as long as it can finely pulverize soybeans.

The soybean protein denaturation step S3', which is step 3, includes a heating step S3'-1 in which the soybeans are steamed and heated, and a steaming step S3'-2 in which the steamed soybeans are steamed so that the moisture is uniformly absorbed. consists of

The heating step S3'-1 is a step of heating the pulverized soybeans pulverized in the soybean pulverizing step S2' in a steamer. At this time, the temperature inside the pot is heated to 80°C to 100°C. By doing so, the inside of the kettle becomes a superheated steam state or a high-temperature saturated steam state close to it. The inside of the pot, which is in a superheated steam state or a high-temperature saturated steam state close to it, is filled with steam and the air is removed, so that it becomes anoxic state or low oxygen state. That is, since the pulverized soybeans inside the pot are heated in an oxygen-free or low-oxygen condition, soybean protein can be denatured while preventing oxidation. By denaturing the soy protein by heating, the denatured soy protein is coagulated in the coagulation step S5' described later, and tofu can be produced from soy milk. At this time, foam is generated by heating due to the surfactant effect of soybean saponin, but unlike the conventional manufacturing method, the amount of foam generated is small and the use of an antifoaming agent is not necessary because there is less moisture.

In the steaming step S3'-2, the soybeans heated in the heating step S3'-1 are steamed for about 5 to 13 minutes to evaporate excess water and to create a state in which the ground soybeans are evenly moistened. be. That is, the steamed ground soybeans should not be too partially soaked or too dry. Moreover, all or most of the above-mentioned bubbles disappear naturally within this steaming time.

The extraction step S4', which is step 4, is a step of separating soybean milk and bean curd refuse from the crushed soybeans that have been steamed and heated with steam. As a specific separation method, the soybean milk and bean curd refuse are separated by straining the crushed soybeans heated in the soybean protein denaturation step S3' through a mesh. By filtering the heated pulverized soybeans through a mesh, the soymilk and okara are separated. Therefore, even if the bubbles generated in the heating step S3'-1 remain, the bubbles are not mixed with the extracted soymilk. disappears. In addition, a method using a mesh is used as a method for separating the soymilk and okara, but any method may be used as long as the soymilk and okara can be separated. You can do it by squeezing.

The coagulation step S5', which is step 5, is a step of adding a coagulant to the soymilk obtained in the extraction step S4' to coagulate the soymilk. Specifically, the soymilk extracted in the extraction step S4' is poured into a stainless steel mold and a coagulant is added. The soymilk is heated in the preceding soybean protein denaturation step S3' to denature the soybean protein, thereby ensuring coagulation by the coagulant. The coagulant used here may be a method using a metal salt such as magnesium chloride (bittern) or calcium sulfate, or a method using gluconodeltalactone or arrowroot powder. A mixture of a plurality of coagulants, such as a mixture of potassium chloride and magnesium sulfate, may also be used. Further, the coagulant is usually in the form of a powder, and when it is added to the soymilk, it is added as a coagulant liquid produced by using the tofu manufacturing water SW as a medium. A coagulant is added to the soymilk poured into the mold, and the soymilk is completely hardened in about 10 to 30 minutes, completing the production of tofu.

As described above, the softening step S1' of immersing soybeans in tofu manufacturing water SW from which dissolved gas has been removed and overheating are performed as a manufacturing method in which soybeans are not exposed to oxygen more than necessary until the processing of soybeans is completed. By performing a soybean protein denaturation step S2' in which soybeans are heated in a steam state or a high-temperature saturated steam state close to it, oxidation of soybeans in the manufacturing process is prevented and high-quality tofu making the best use of the original taste of soybeans is produced. can be done.

In addition, by steaming and heating the crushed soybeans inside the steamer without the boiling process (the conventional process of denaturing soybean protein) in a state containing a lot of water contained in the conventional tofu manufacturing method, the bubbles can be produced. By minimizing the generation of soybeans and then separating the heated pulverized soybeans with a mesh or the like to obtain soymilk, no bubbles are generated in the soymilk produced.

In other words, it is possible to prevent air bubbles in the tofu caused by bubbles and poor texture caused by entrapment of air bubbles during eating. Furthermore, since no foam is generated, it is not necessary to add an antifoaming agent, and the tofu can be made only with soybeans and a coagulant. Tofu rich in soybean saponin can be produced. Soybean saponin is effective in suppressing active oxygen in the body, improving immunity, and improving liver function. That is, the tofu produced by the method for producing tofu according to the present embodiment rich in soybean saponin can be healthy tofu.

The method of preserving tofu according to the present embodiment includes, as shown in steps 6 to 8 of FIG. It consists of a cut-out enclosing step S7' for enclosing the cut tofu in an actual container for sale, and a cooling step S8' for lowering the temperature of the tofu enclosed in the packaging container to a temperature suitable for storage. Hereinafter, steps 6' and 7 of the tofu storage method procedure according to the present embodiment will be specifically described.

The water tank immersion step S6', which is step 6', is a step of putting the tofu produced in the above-described tofu production method into a water tank filled with water. At this time, tofu manufacturing water SW from which dissolved oxygen has been removed is used as the water in the water tank. That is, by immersing the tofu in the water SW for producing tofu, the produced tofu can be preserved while being prevented from coming into contact with oxygen and being oxidized. As in the softening step S1' of Step 1, the tofu manufacturing water SW is periodically replaced with new tofu manufacturing water SW or inerted with nitrogen or the like so that oxygen does not dissolve in the tofu manufacturing water SW. Oxidation can be further prevented by injecting gas.

The cut-and-enclose step S7', which is Step 7, consists of a cut-out step S7'-1 for cutting out the soaked tofu and an enclosing step S7'-2 for enclosing the cut-out tofu in a container.

The cutting step S7'-1 is a step of cutting the tofu that has been immersed in the water tank in the water tank immersion step S6' so as to fit into the container that will enclose the tofu in the next step.

The enclosing step S7'-2 is a step of storing the tofu cut out in the cutting out step S7'-1 in a container for sale or storage and enclosing it in a sealed state. When storing tofu in the container, the inside of the container is filled with tofu manufacturing water SW in advance. By doing so, the tofu is always immersed in the tofu-manufacturing water SW from which dissolved oxygen has been removed at the time of sale or storage, so that deterioration of taste can be prevented without oxidation. Moreover, it is desirable that the container in which the tofu is enclosed should be a container that is difficult for oxygen to permeate.

The cooling step S8', which is step 8, is a step of lowering the packaging container containing the tofu and the tofu manufacturing water SW in the enclosing step S7' to a temperature suitable for storage. This cooling step S8' is performed in the same manner as the boil-cool step performed in the conventional tofu manufacturing method. That is, the packaging container enclosing the tofu and the tofu manufacturing water SW is cooled to about 5° C. by the cooling water in the cooling tank. However, since the boiling process (heat sterilization process) in the conventional manufacturing process is not performed, the temperature of the tofu before cooling is lower than before, and the time required for cooling can be greatly shortened. can.

The method and apparatus for producing and storing tofu described above are aimed at producing tofu, but needless to say, they can also be used for producing processed soybean products such as soymilk and fried tofu. Also, when producing fried tofu, it is necessary to add water in the heating process, so in that case, the tofu production water stored in the production water tank may be supplied to the heating device.

Moreover, the description of the above-described embodiment is an example of the present invention, and the method for producing tofu and the method for storing tofu according to the present invention are not limited to the above-described embodiment. Therefore, it goes without saying that various modifications other than the above-described embodiments are possible according to the design and the like, as long as they do not deviate from the technical idea of the present invention. Moreover, the various effects described above are merely examples, and the effects of the present invention are not limited to those described in this embodiment.

S1 Softening step S2 Draining step S3 Grinding step S4 Heating step S5 Extraction step S6 Solidification step S7 Cutting step S8 Encapsulation step S9 Cooling step M Tofu manufacturing apparatus W Water SW Water for tofu manufacturing 100 Manufacturing water generator 110 Water tank 120 Dissolved oxygen removal Apparatus 130 Dissolved oxygen measuring device 140 Production water tank 200 Soybean processing device 210 Immersion tank 220 Draining device 230 Grinding device 231 Grinding part 232 Raw soybean soup receiving part 233 Supply pipe 240 Heating device 250 Extraction device 260 Coagulation frame 300 Packaging cooling device 310 Cutting device 320 Packaging device 321 Tofu manufacturing water supply section C Conveyor 330 Cooling device 400 Water supply section S1' Softening step S2'S2' Soybean crushing step S2'-1 Draining step S2'-2 Crushing step S3' Soybean protein denaturation step S3 '-1 Heating process S3'-2 Steaming process S4' Extraction process S5' Solidification process S6' Water tank immersion process S7' Cutting and enclosing process S7'-1 Cutting process S7'-2 Enclosing process S8' Cooling process

Claims (2)

A method for producing and preserving tofu that enables setting a long expiration date without heat sterilization after encapsulation in a packaging container,
Water from which dissolved oxygen has been removed is used as tofu manufacturing water,
It is used in all the steps of soaking, grinding, and cutting that come into contact with water related to tofu production,
filling the inside of the packaging container with the tofu manufacturing water,
A method for producing and preserving tofu, characterized by encapsulating tofu in a soaked state. A tofu manufacturing apparatus comprising a manufacturing water generating device for generating the tofu manufacturing water from which dissolved oxygen contained in water has been removed,
The manufacturing water generator includes a water tank for storing water containing dissolved oxygen,
a dissolved oxygen removal device for removing dissolved oxygen from the water stored in the water tank;
a dissolved oxygen measuring device for measuring the amount of dissolved oxygen contained in the tofu manufacturing water generated by the dissolved oxygen removing device;
a production water tank for storing the tofu production water;
A tofu manufacturing apparatus characterized by comprising:

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