Method for producing fermented dried tofu flakes
By pickling, soaking in rice koji, and applying mold, the method enhances soy protein breakdown in tofu, producing fermented dried tofu flakes with increased umami content for vegetarian cuisine and seasoning applications.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- F·D·T LTD
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for producing dried tofu fail to fully utilize soy proteins, resulting in insufficient extraction of umami and dashi components, limiting their use in vegetarian cuisine and as a seasoning for those avoiding animal-based broths.
A method involving pickling tofu in salt water, soaking in rice koji to break down proteins, and applying mold to promote fermentation and drying, which includes a final drying process to produce fermented dried tofu flakes.
The method effectively breaks down soy proteins into amino acids, enhancing the umami content and enabling the production of hard fermented dried tofu flakes suitable for use as an ingredient and seasoning in vegetarian cuisine and for those avoiding animal-based broths.
Smart Images
Figure 2026082170000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for producing fermented dried katsuobushi that can produce katsuobushi containing more dashi components from soy proteins in tofu, and is a method for producing fermented dried katsuobushi suitable for producing dashi for shojin cuisine.
Background Art
[0002] Dishes that do not use animal-based dashi have long been known as shojin cuisine in relation to Buddhist teachings. Representative examples of the dashi used in this shojin cuisine include kelp and shiitake. Furthermore, during the Heian period, it became possible to make dried tofu by applying salt to tofu and drying it, and this dried tofu was thinly sliced and used in shojin cuisine and the like as an aid for dashi.
[0003] This dried tofu is called shojin katsuobushi or rokujo tofu, and rokujo tofu made at "Tofu Workshop Seiryu-an" in Kanawa-cho, Yamagata Prefecture is still used in some shojin cuisine. However, since this rokujo tofu is made by directly applying salt to dehydrated tofu and drying it, as the salt concentration is high, the proteins in the tofu have not been fully utilized as dashi, and the umami of soy proteins could not be fully extracted.
[0004] On the other hand, as prior art related to dried tofu, the following Patent Document 1 is known. This Patent Document 1 provides lactic acid-fermented tofu obtained by fermenting Okinawa-produced island tofu with lactic acid bacteria. Then, appropriate pressure treatment is performed on the Okinawa-produced island tofu to squeeze out and remove the contained moisture, and lactic acid bacteria are further added to the pickling juice prepared using miso, mirin, sugar, a small amount of sake, etc. to the tofu, and fermentation is carried out for a certain period to impart unique flavor, texture, and functionality.
Prior Art Documents
Patent Documents
[0005] [[ID=so]]
Patent Document 1
[0006] Patent Document 1, mentioned above, describes a technology for manufacturing dried tofu. However, this dried tofu was made by fermenting tofu in red yeast rice or awamori (Okinawan rice liquor), and was a type of "tofuyo" unique to the Ryukyu region, so it was not possible to bring out the umami of the soy protein.
[0007] In response to this, there was a need for a broth used in vegetarian cuisine that could not only be used as an ingredient in vegetarian dishes, but also as a seasoning for people who do not consume animal-based broths or who avoid using umami seasonings. For this reason, it was necessary to develop tofu flakes, a type of vegetarian broth that contains more broth components from the soy protein in tofu.
[0008] This invention was made in view of the above background, and aims to provide a method for producing fermented dried tofu flakes that can produce tofu flakes containing more dashi components from the soy protein in tofu. [Means for solving the problem]
[0009] The invention described in claim 1, which solves the above problem, involves pickling tofu in salt water, Next, the tofu is soaked in rice koji to break down the tofu's protein, and then mold is applied to the tofu. This is a method for producing fermented and dried tofu flakes, which involves a final drying process.
[0010] According to the method for producing fermented dried tofu flakes as described in Claim 1, the salt concentration can be kept low because the tofu is simply soaked in salt water. Furthermore, by soaking the tofu in rice koji to break down the tofu's protein, then inoculating the tofu with mold, and finally drying it, a hard fermented dried tofu flake similar to katsuobushi is produced.
[0011] As a result of the above, this manufacturing method allows for the breakdown of soy protein in tofu from peptides, which are the source of nutrients and flavor, into amino acids, making it possible to produce hard fermented dried tofu flakes containing more dashi components. In other words, this fermented dried tofu flakes can be used not only as an ingredient in vegetarian cuisine, but also as a suitable seasoning ingredient for people who do not consume animal-based broths or who avoid using umami seasonings.
[0012] According to the method for producing fermented dried tofu flakes as described in claim 2, by dehydrating the tofu before soaking it in brine, the moisture in the tofu can be actively removed, and effective absorption of brine can be made possible when soaking it in brine. According to the method for producing fermented dried tofu flakes as described in claim 3, when dehydrating the tofu, most of the water can be removed by applying pressure to the tofu while cooling it for 10 to 15 hours, which allows for the appropriate absorption of saltwater when soaking it in saltwater afterward.
[0013] According to the method for producing fermented dried tofu flakes as described in claim 4, in the step of soaking the tofu in brine, soaking it in 5% brine for 10 to 15 hours while cooling it effectively promotes the decomposition of soy protein in the tofu and prevents spoilage of the tofu when mold is applied to the tofu.
[0014] According to the method for producing fermented dried tofu flakes as described in claim 5, when soaking the tofu in rice koji and then applying mold to the tofu, the method includes a primary mold application step in which rice koji is grown deep within the tofu, and a secondary mold application step in which koji mold for katsuobushi production is applied.
[0015] While soaking tofu in rice koji breaks down the soy protein on the surface, further mold cultivation is necessary to make tofu suitable for dashi (broth). Therefore, a primary mold cultivation process is performed because the mold breaks down the soy protein in deeper parts of the tofu, and the rice koji requires moisture to grow in the tofu, thus assisting in the removal of moisture from deeper layers.
[0016] Furthermore, in the secondary mold-attachment step, by further attaching and propagating koji mold for making dried bonito to the fat contained in the dehumidified tofu, the decomposition of soy protein is promoted to refine the flavor, and since koji mold requires moisture during propagation and can further remove the deep moisture, the tofu becomes as hard as dried bonito.
Advantages of the Invention
[0017] As described above, according to the present invention, there is an excellent effect that a method for producing fermented and dried tofu cubes containing more juice components from soy protein in tofu can be obtained.
Brief Description of the Drawings
[0018] [Figure 1] It is a diagram showing a manufacturing process chart of fermented and dried tofu cubes according to an embodiment of the present invention. [Figure 2] It is a diagram showing tofu in the first step according to an embodiment of the present invention. [Figure 3] It is a diagram showing a state in which a weight is placed on the tofu in the first step according to an embodiment of the present invention. [Figure 4] It is a diagram showing the immersion of tofu in salt water in the second step according to an embodiment of the present invention. [Figure 5] It is a diagram showing the immersion of tofu in rice koji in the third step according to an embodiment of the present invention. [Figure 6] It is a diagram showing the first mold-attachment to the tofu in the fourth step according to an embodiment of the present invention. [Figure 7] It is a diagram showing a state in which the first mold-attachment to the tofu in the fourth step according to an embodiment of the present invention is completed. [Figure 8] It is a diagram showing a state in which the second mold-attachment to the tofu in the fifth step according to an embodiment of the present invention is completed.
Modes for Carrying Out the Invention
[0019] Hereinafter, one embodiment of the method for producing fermented dried tofu flakes according to the present invention will be described in detail with reference to the drawings. This embodiment aims to produce a hard, fermented, dried tofu flake similar to bonito flakes, which can be used not only as an ingredient in vegetarian cuisine, but also as a seasoning for people who do not consume animal-based broth or who avoid using umami seasonings.
[0020] In the method for producing fermented and dried tofu flakes according to this embodiment, tofu that is fermented and dried is first prepared in advance, such as commercially available firm tofu with a high proportion of soybeans. Firm tofu is used because the amount of soybeans needed to make one block of firm tofu is typically 77-90g, and its manufacturing process results in a low water content and a high soybean (soy milk) content, making it suitable for the production of tofu flakes. In contrast, packaged tofu, like firm tofu, is made by mixing soy milk with nigari (magnesium chloride) and then filling it directly into a container. As a result, it has a high water content, is smooth and soft, and is not ideal for the production of tofu flakes, although it can be used.
[0021] Tofu flakes are manufactured following the procedure shown in the manufacturing process chart in Figure 1, with the first step being the dehydration of the tofu. Dehydration is necessary to remove as much water as possible from the tofu, thereby accelerating the breakdown of soy protein in the tofu in the next step and promoting the absorption of salt water to prevent spoilage.
[0022] Specifically, ten blocks of tofu 10 are arranged in a dewatering tray 12 having drainage holes at the bottom, as shown in Figure 2. A board or similar material is placed on top of the tofu, and then a weight 14, such as a 2-3 kg weight, is placed on top of that, as shown in Figure 3. The tofu 10 is then dewatered in a refrigerator at a temperature of 5-8°C for, for example, 12 hours while pressure is applied. The dewatering time may be between 10 and 15 hours. However, the number of tofu 10 can be changed depending on the size of the dewatering tray 12, but the pressure for dewatering should be 200-300 g per block. The dewatering method does not have to be limited to the method described, but the weight used during dewatering should not be too heavy as it may crush the tofu 10.
[0023] The second step is to soak the tofu in saltwater SW. The purpose of soaking the tofu 10 in saltwater SW is to accelerate the breakdown of the protein in the tofu 10 and to prevent spoilage of the tofu 10 when mold is applied to it. Specifically, in the first step, 10 blocks of tofu 10 that have been dehydrated in the refrigerator for 10 to 15 hours are removed along with the dehydration tray 12, and the 10 blocks of tofu 10 are transferred to a pickling tray 16 containing 5% salt solution SW as shown in Figure 4, and the tofu 10 in the pickling tray 16 are then immersed again in the refrigerator for 10 to 15 hours. However, the time may be changed depending on the degree of dehydration.
[0024] The third step is the process of soaking the tofu in rice koji. In the second step, the salted tofu 10 is taken out of the refrigerator and placed in 1 liter of 0.5% saline solution mixed with 200g of pre-prepared rice koji with strong protease activity (koji for soy sauce or miso), which is then added to the 10 blocks of tofu 10 shown in Figure 5. The tofu 10 is then immersed in this mixed solution ML, which is considered to be saline solution containing enzymes produced by the rice koji, at room temperature of 25-30°C by stirring, for 2-5 hours, so that the tofu 10 is coated with this mixed solution ML.
[0025] However, for optimal results, it is recommended to soak the tofu at room temperature for 3 to 4 hours. On the other hand, if soaked for more than 5 hours, the soy protein in the tofu may decompose too much, potentially affecting the taste and resulting in a stronger bitterness in the finished product.
[0026] In short, this process aims to break down the soy protein in tofu 10 from peptides, which are the source of nutrients and flavor, to amino acids. The rice koji used at this time is made using Aspergillus oryzae koji mold for soy sauce or miso. Rice koji with strong amylase activity is not used here. Furthermore, in the process of breaking down the soy protein in tofu 10, the tofu 10 is soaked in brine SW in the second step, making it less likely to spoil. In addition, while barley koji is usually used for soy sauce koji, we use our own rice koji due to allergy labeling requirements, but it is also acceptable to purchase rice koji from an external source.
[0027] The fourth step is the primary mold application process to the tofu 10. In the third step, the soy protein on the surface of the tofu 10 is broken down, but moisture remains in the deeper parts, and as it is, it does not become a dried bonito flake and cannot be used as a dashi broth bonito flake. In order to make it into a dashi broth bonito flake, it is necessary to further break down the soy protein in the deeper parts of the tofu 10, and since rice koji requires moisture to grow on the tofu 10, mold is added as it is expected to play an auxiliary role in removing moisture from the deeper parts.
[0028] Specifically, the 10 blocks of tofu 10 that have completed the third step are removed from the saline solution SW and placed in a special basket 18. At this time, in order to ensure that the rice koji KM adheres firmly to the tofu 10 and promotes its growth, the tofu 10 are coated with rice koji KM as shown in Figure 6. Then, this special basket 18 with the tofu 10 is placed in a dehumidifying dryer and dehumidified under the following conditions to cultivate koji mold on the tofu 10. During this dehumidified cultivation, the tofu 10 are turned over every 12 hours. Dehumidifier temperature setting: 30-40℃ Dehumidified culture time 24~72 hours Furthermore, after the dehumidification culture is complete, the tofu 10, in which the rice koji KM has grown well, is removed from the dehumidifier as shown in Figure 7, and the rice koji KM on the surface of the tofu 10 is removed. The dehumidifier was set to a temperature of 30-40°C, but the maximum temperature was 50°C as this also served to encourage mold growth.
[0029] The fifth step is the secondary mold inoculation process. This process aims to make the tofu 10, which has been first mold-inoculated and dehumidified in the fourth process, as hard as bonito flakes. In this fifth process, koji mold KK, used for bonito flake production, is applied to the fat content of the tofu 10 and allowed to grow, thereby promoting the breakdown of soy protein and refining the flavor. Furthermore, since koji mold requires moisture to grow, further moisture removal from the deeper parts of the tofu is achieved, resulting in the tofu 10 becoming as hard as bonito flakes.
[0030] Specifically, the tofu 10, after the fourth step is completed, is immersed again for 5 to 20 minutes in a 0.5% saline solution SW mixed with pre-prepared rice koji, or the tofu 10 is immersed or sprayed for 5 to 20 minutes in water in which the starter koji used for rice koji has been dissolved. The koji mold used here is Aspergilus glaucus or repens cultured in rice koji, which has been developed in-house, or if spraying with Aspergillus oryzae is to be done, Eurotium herbariorum will be used. The basket containing the tofu 10 is then placed back into a dehumidifying dryer, and mold is applied to the tofu 10 while culturing it in a dehumidifying environment under the following conditions. However, the tofu 10 is turned over every 12 hours during this dehumidifying cultivation.
[0031] Dehumidifier temperature setting: 30-40℃ Dehumidified culture time 12~36 hours As a result of the above, once the katsuobushi mold has grown on the surface of the tofu 10 as shown in Figure 8, the dehumidified culture is terminated. After the dehumidified culture is completed, the tofu 10 is removed from the dehumidifying dryer and the koji mold KK that has grown on the surface of the tofu 10 is removed. Note that this secondary mold inoculation step is not necessarily required, and the product can be considered complete after the fourth step, but completing this fifth step results in higher quality tofu flakes.
[0032] The sixth step is the final drying process. To improve the shelf life of the tofu flakes, which are almost complete after the fourth or fifth step, the moisture content is reduced to 5% or less, and the surface of the tofu flakes is dried for sterilization. Specifically, the tofu flakes that have undergone mold cultivation and drying, as well as mold removal, are placed on drying trays and dried in a hot air dryer at 75°C for 1 to 10 hours. The specific drying time is determined based on the moisture content measured up to the previous step.
[0033] The seventh step is considered the finishing step. This process involves cooling the dried tofu flakes, which were finished and dried in the sixth step, and then packaging them into finished products. These finished tofu flakes are then transported to retail stores or mailed to consumers who place orders online.
[0034] Examples of uses for the "fermented dried tofu flakes" produced by this embodiment include the following: First, thinly slicing "fermented dried tofu flakes" and adding them when making dashi (broth) from other ingredients such as kelp, shiitake mushrooms, and vegetables can create a rich, flavorful broth. Furthermore, finely grinding "fermented dried tofu flakes" and mixing them into salad dressings can create a more flavorful dressing. Additionally, coarsely grinding "fermented dried tofu flakes" and placing them in a dashi bag allows you to create single-use dashi packets.
[0035] Based on the above, the method for producing fermented dried tofu flakes according to this embodiment allows for the development of fermented dried tofu flakes (also called tofu flakes or vegetarian flakes) containing more umami components by breaking down the soy protein in tofu into amino acids or peptide units that are the source of umami. As a result, the produced fermented dried tofu flakes can be used not only as an ingredient in vegetarian cuisine, but also as a seasoning ingredient for people who do not consume animal-based broth or who avoid using umami seasonings. Accordingly, by shaving these fermented dried tofu flakes like katsuobushi and adding them to broth, it is possible to create a vegetarian broth that does not use animal-based ingredients.
[0036] In the above embodiment, fermented and dried tofu flakes were produced in units of 10 blocks of tofu, but this is merely an example, and they may be produced in units of 20 blocks or more. Also, in the second step, 10 blocks of tofu were transferred to a pickling tray 16 containing 5% salt solution SW, but a salt solution SW of 5-20% concentration may be used.
[0037] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention. [Industrial applicability]
[0038] The present invention relates to a method for producing fermented dried tofu flakes, which can produce tofu flakes containing more dashi components from the soy protein in tofu, for example. Although intended for the production of dashi for vegetarian cuisine, it can also be applied to dashi for ordinary cooking other than vegetarian cuisine. [Explanation of symbols]
[0039] 10 Tofu 12 Dehydration trays 14 weights 16 Pickling trays 18 Dedicated basket KK Koji mold KM rice koji ML mixture SW Saltwater
Claims
1. Soak the tofu in salt water, Next, the tofu is soaked in rice koji to break down the tofu's protein, and then mold is applied to the tofu. A method for producing fermented and dried tofu flakes, which involves a final drying process.
2. A method for producing fermented dried tofu flakes according to claim 1, wherein the tofu is dehydrated before being soaked in brine.
3. A method for producing fermented dried tofu flakes according to claim 2, wherein the tofu is dehydrated by applying pressure while being cooled for 10 to 15 hours.
4. The method for producing fermented dried tofu flakes according to claim 1, wherein the tofu is immersed in a 5% salt solution for 10 to 15 hours while being cooled during the step of soaking the tofu in salt water.
5. A method for producing fermented dried tofu flakes according to claim 1, comprising a primary mold inoculation step in which rice koji is grown deep within the tofu after soaking the tofu in rice koji, and a secondary mold inoculation step in which koji mold for katsuobushi production is applied.