Hot water bean soaking process and fermented bean curd production method
Through the slightly acidic high-temperature bean soaking process, the problems of long soaking beans, high energy consumption and microbial contamination are solved, and high-quality fermented bean products are achieved efficiently.
Patent Information
- Application Number
- CN202510714298.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-29
AI Technical Summary
The existing bean soaking process has a long time, high energy consumption, low soybean output rate, poor quality of fermented bean curd products, and high risk of microbial contamination.
The bean soaking process with slightly acidic (pH 5.5-6.0) and high-temperature conditions is used to soak it in two steps to shorten the soaking time, improve the protein dissolution rate, and reduce microbial contamination.
Shorten the time to soak beans, reduce the rate of stagnant beans, improve the output rate of soybeans, improve the quality and flavor of fermented bean curd products, and reduce microbial pollution.
Smart Images
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of fermented bean curd processing, and particularly to a hot water soaking process for soybeans and a method for producing fermented bean curd. Background Art
[0002] The existing soybean soaking process controls the soaking time by natural soaking according to different seasons and water temperatures. The soybean soaking process mainly soaks soybeans at a ratio of raw materials to fresh water of 1:3, and mainly includes the following operations: 1) When the water temperature ≥ 25 °C, the soaking time is 6 - 8 hours; 2) When the water temperature is 20 - 25 °C, the soaking time is 8 - 10 hours; 3) When the water temperature is 15 - 20 °C, the soaking time is 10 - 12 hours; 4) When the water temperature ≤ 15 °C, the soaking time is 12 - 14 hours.
[0003] The existing method for producing fermented bean curd includes the following steps: taking soybeans, screening, soaking soybeans at room temperature, grinding soybeans, boiling soybean milk, making embryos, fermenting the embryo with Mucor, pickling, bottling, post - ripening, and packaging to obtain fermented bean curd. Soaking soybeans at room temperature has a long soaking time, high energy consumption, low soybean yield, and poor quality of the obtained fermented bean curd products. Summary of the Invention
[0004] The purpose of this application is to overcome the deficiencies of the above - mentioned existing technologies and provide a hot water soaking process for soybeans and a method for producing fermented bean curd.
[0005] To achieve the above purpose, the technical solution adopted in this application is as follows:
[0006] This application provides a hot water soaking process for soybeans, including the following steps:
[0007] S1. Adjust the pH value of water to 5.5 - 6.0, heat it to 80 - 85 °C, then put soybeans into the treated water for soaking, and then drain the water;
[0008] S2. Adjust the pH value of water to 5.5 - 6.0, heat it to 70 °C - 85 °C, and then add the water to the soybeans treated in step S1 for soaking.
[0009] This application discovers that dividing the hot water soaking process for soybeans into two steps and adopting a slightly acidic (pH 5.5 - 6.0) and high - temperature condition can shorten the soaking time, reduce energy consumption, lower the rate of stiff soybeans, increase the dissolution rate of protein, and thus improve the soybean yield. By soaking soybeans in two steps, the temperature difference between the outside and inside of soybeans is reduced, making the soybeans absorb water evenly and fully soaking and absorbing water in a short time; moreover, this application adopts a slightly acidic high - temperature soaking process for soybeans, which can also reduce the microbial contamination during the soaking process and stably improve the quality of fermented bean curd products.
[0010] This application provides a method for producing fermented bean curd, including the following steps:
[0011] 1) Adjust the pH value of water to 5.5 - 6.0, heat it to 80 - 85 °C, then soak soybeans in the treated water, and then drain the water.
[0012] 2) Adjust the pH value of water to 5.5 - 6.0, heat it to 70 °C - 85 °C, and then add the water to soak the soybeans treated in step 1).
[0013] 3) Grind, filter, separate the pulp from the residue of the soybeans treated in step 2), and then cook the pulp.
[0014] 4) Mix the cooked soybean milk with a coagulant, perform bean curdling and waiting, pressing, cutting the milk embryo, then ferment and pickle the milk embryo with Mucor to obtain a salty embryo, pour the fermented bean curd soup into the salty embryo for post - fermentation to obtain fermented bean curd.
[0015] The method for producing fermented bean curd of this application adopts the above - mentioned slightly acidic high - temperature soybean soaking process, which can shorten the soybean soaking time, solve the problem of the rigid bean rate caused by natural soybean soaking. The rigid bean rate can be reduced from about 3% to less than 0.05%, improve the dissolution rate of protein, and thus improve the output rate of soybeans. Moreover, the above - mentioned soybean soaking process can also reduce the microbial contamination during the soybean soaking process and stably improve the quality of fermented bean curd products.
[0016] The soybean soaking process adopted in this application eliminates the defects of the traditional old method, that is, natural water absorption for soybean soaking with unstable time and relying on artificial experience control. For soybeans soaked at high temperature, the soybeans are fully soaked and soft, easy to grind, and the protein and other nutrients in the soybeans are easy to extract, improving the output rate of soybeans.
[0017] Applying the soybean soaking process to the method for producing fermented bean curd of this application improves the soybean soaking efficiency, and thus improves the soybean soaking quality. Moreover, the overall flavor of the fermented bean curd products obtained by applying the above - mentioned production method is more harmonious and the fresh and sweet taste is better.
[0018] As a preferred embodiment of the method for producing fermented bean curd described in this application, the ratio of the weight of soybeans to the total weight of water is 1:(3.5 - 4.5). Preferably, the ratio of the weight of soybeans to the total weight of water is 1:4.
[0019] When the mass ratio of soybeans to water in this application is the above - mentioned mass ratio, soybeans can be better soaked, the output rate of soybeans can be improved, and the soybean soaking quality can be improved.
[0020] As a preferred embodiment of the method for producing fermented bean curd described in this application, in step 1), the soaking time is 0.5 - 1 h; in step 2), the soaking time is 1 - 2 h.
[0021] The present application adopts the method of soaking soybeans in a high temperature environment and matching the soaking time, so that the soybeans obtained by soaking are fully soaked and soft, and the slurry is easy to grind, and the protein and other nutrients in the soybeans are easy to extract.
[0022] Furthermore, the above soaking conditions shorten the soaking time, reduce energy consumption, improve production efficiency, reduce the stiff bean rate, increase the protein dissolution rate, and thus increase the soybean output rate.
[0023] As a preferred embodiment of the fermented bean curd production method described in the present application, in step 3), the boiling temperature is 98 to 105° C., and the boiling time is 1 to 2 minutes.
[0024] As a preferred embodiment of the fermented bean curd production method described in the present application, in step 4), the conditions for the Mucor fermentation are: the fermentation time is 34 to 36 hours, and the fermentation temperature is 31 to 33°C.
[0025] By adopting the above fermentation conditions, fermented bean curd can be prepared better with a more harmonious flavor.
[0026] As a preferred embodiment of the fermented bean curd production method described in the present application, in the step 4), the pickling time is 6 to 8 hours.
[0027] As a preferred embodiment of the fermented bean curd production method described in the present application, in step 4), the post-fermentation time is 40 to 60 days.
[0028] As a preferred embodiment of the fermented bean curd production method described in the present application, the fermented bean curd soup includes edible alcohol, edible refined salt and water, and the mass ratio of edible alcohol, edible refined salt and water is 50:8:42.
[0029] As a preferred embodiment of the fermented bean curd production method described in the present application, the mass ratio of the soy milk to the coagulant is 1:(0.1-0.15).
[0030] When the mass ratio of soy milk to coagulant is within the above range, it is easy to obtain embryo.
[0031] Compared with the prior art, this application has the following beneficial effects:
[0032] This application provides a hot water soaking process for soybeans and a method for producing fermented bean curd. This application uses slightly acidic (pH 5.5-6.0) and high temperature conditions to shorten the soaking time, reduce energy consumption, lower the rate of stiff beans, increase the protein dissolution rate, and thus increase the soybean yield. Furthermore, this application uses a slightly acidic, high-temperature soaking process to reduce microbial contamination during the soaking process, steadily improving the quality of the fermented bean curd product, and resulting in a more harmonious overall flavor and a better fresh and sweet taste. DETAILED DESCRIPTION
[0033] To better illustrate the purpose, technical solution, and advantages of the present application, the present application will be further described below in conjunction with specific embodiments.
[0034] In the following examples and comparative examples, unless otherwise specified, the experimental methods used are conventional methods, and the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified, and the component raw materials used in each parallel experiment are of the same kind.
[0035] Example 1
[0036] This example provides a method for producing fermented bean curd, including the following steps:
[0037] 1) Raw material treatment: Remove impurities from soybeans, and remove foreign substances through an impurity removal machine to obtain clean soybean raw materials.
[0038] 2) Soaking soybeans in hot water: Soak soybeans according to the ratio of raw materials to clear water of 1:4:
[0039] A. First stage: Adjust the pH of the water to 5.6, heat it to 83°C, put the weighed soybeans into the hot water and start soaking for 1 hour, then drain the water;
[0040] B. Second stage: Adjust the pH of the water to 5.5, heat it to 80°C, quantitatively add it to the soybeans in the first stage, and soak for 2 hours. The total soaking time is 3 hours, and the water absorption rate of the beans is 1.2 times that of soybeans.
[0041] 3) Grinding the soybeans: Grind the soybeans according to the required ratio, and the operation is to grind while adding water.
[0042] 4) Filtration: Vibration-filter the cooked soybean milk to separate the pulp from the residue; then adjust the concentration of the soybean milk and cook it.
[0043] 5) Cooking the soybean milk: Control the cooking temperature of the soybean milk at 98 - 105°C and maintain it for 1 minute.
[0044] 6) Coagulating the soybean milk and letting it stand: Add a coagulant (magnesium chloride) and soybean milk according to the required ratio, then slowly stir the soybean milk until it forms flowers and stop stirring to let it stand.
[0045] 7) Pressing: Press according to the specified requirements, and ensure even pressing.
[0046] 8) Cutting the fermented bean curd embryos: Cut the embryos into pieces according to the size requirements of different product specifications.
[0047] 9) Fermentation of the fermented bean curd embryos with Mucor: 36h, 32°C.
[0048] 10) Pickling the fermented bean curd embryos: Pickle the fermented bean curd embryos that have matured with Mucor with salt for 6 - 8 hours to obtain salty embryos.
[0049] 11) Fermentation after bottling: The salty embryo is placed in a bottle and filled with fermented bean curd soup (the fermented bean curd soup is composed of edible alcohol, edible refined salt and water in a mass ratio of 50:8:42).
[0050] 12) Post-fermentation and maturity for 45 days.
[0051] 13) Labeling and warehousing: Attach labels to the packaging bottles and put them into the warehouse.
[0052] Example 2
[0053] Compared with Example 1, Example 2 is different in step 2), and the other steps are the same as Example 1.
[0054] 2) Soak beans in hot water: Soak beans in a ratio of 1:4 between raw materials and water.
[0055] A. Stage 1: Adjust the pH of the water to 5.6, heat it to 83°C, place the weighed soybeans in the hot water and soak for 1 hour, then drain the water.
[0056] B. Second stage: Adjust the pH of water to 5.7, heat to 70℃, add quantitatively into the soybeans in the first stage, and soak for 1.5 hours. The total soaking time is 2.5 hours. The water absorption rate of soybeans is 1.22 times that of soybeans.
[0057] Example 3
[0058] Compared with Example 1, Example 3 is different in step 2), and the other steps are the same as Example 1.
[0059] 2) Soak beans in hot water: Soak beans in a ratio of 1:4 between raw materials and water.
[0060] A. Stage 1: Adjust the pH of the water to 5.6, heat it to 83°C, place the weighed soybeans in the hot water and soak for 1 hour, then drain the water.
[0061] B. Second stage: Adjust the pH of water to 5.6, heat to 75℃, add quantitatively to the soybeans in the first stage, and soak for 1 hour. The total soaking time is 2 hours. The water absorption rate of soybeans is 1.21 times that of soybeans.
[0062] Example 4
[0063] Compared with Example 1, Example 4 is different in step 2), and the other steps are the same as Example 1.
[0064] 2) Soak beans in hot water: Soak beans in a ratio of 1:4 between raw materials and water.
[0065] A. Stage 1: Adjust the pH of the water to 5.6, heat it to 83°C, place the weighed soybeans in the hot water and soak for 0.5 hours, then drain the water.
[0066] B. Second stage: adjust the pH of water to 5.7, heat to 75℃, add quantitatively to the soybeans in the first stage, and soak for 1 hour. The total soaking time is 1.5 hours. The water absorption rate of soybeans is 1.2 times that of soybeans.
[0067] Example 5
[0068] Compared with Example 1, Example 5 is different in step 2), and the other steps are the same as Example 1.
[0069] 2) Soak beans in hot water: Soak beans in a ratio of 1:4 between raw materials and water.
[0070] A. Stage 1: Adjust the pH of the water to 5.5, heat it to 80°C, place the weighed soybeans in the hot water and soak for 1 hour, then drain the water.
[0071] B. Second stage: adjust the pH of water to 5.5, heat to 70℃, add quantitatively into the soybeans in the first stage, and soak for 2 hours. The total soaking time is 3 hours. The water absorption rate of soybeans is 1.2 times that of soybeans.
[0072] Example 6
[0073] Compared with Example 1, Example 6 is different in step 2), and the other steps are the same as Example 1.
[0074] 2) Soak beans in hot water: Soak beans in a ratio of 1:4 between raw materials and water.
[0075] A. Stage 1: Adjust the pH of the water to 6.0, heat it to 85°C, place the weighed soybeans in the hot water and soak for 1 hour, then drain the water.
[0076] B. Second stage: Adjust the pH of water to 6.0, heat to 85℃, add quantitatively into the soybeans in the first stage, and soak for 2 hours. The total soaking time is 3 hours. The water absorption rate of soybeans is 1.2 times that of soybeans.
[0077] Comparative Example 1
[0078] Compared with Example 1, Comparative Example 1 is different in step 2), and the other steps are the same as Example 1.
[0079] 2) Soaking beans: Soak the beans in a ratio of raw materials to clean water of 1:4, the water temperature is 30℃, the soaking time is 7 hours, and the water absorption rate of the beans is 1.21 times that of soybeans.
[0080] Comparative Example 2
[0081] Compared with Example 1, Comparative Example 2 is different in step 2), and other steps are the same as those in Example 1.
[0082] 2) Soaking soybeans: Soak soybeans at a ratio of raw materials to clear water of 1:4. The water temperature for soaking soybeans is 25°C, the soaking time is 8 hours, and the water absorption rate of soybeans is 1.21 times that of soybeans.
[0083] Comparative Example 3
[0084] Compared with Example 1, Comparative Example 3 is different in step 2), and other steps are the same as those in Example 1.
[0085] 2) Soaking soybeans: Soak soybeans at a ratio of raw materials to clear water of 1:4. The water temperature for soaking soybeans is 20°C, the soaking time is 10 hours, and the water absorption rate of soybeans is 1.21 times that of soybeans.
[0086] Comparative Example 4
[0087] Compared with Example 1, Comparative Example 4 is different in step 2), and other steps are the same as those in Example 1.
[0088] 2) Soaking soybeans: Soak soybeans at a ratio of raw materials to clear water of 1:4. The water temperature for soaking soybeans is 15°C, the soaking time is 12 hours, and the water absorption rate of soybeans is 1.21 times that of soybeans.
[0089] Comparative Example 5
[0090] Compared with Example 1, Comparative Example 5 is different in step 2), does not contain the second stage, and other steps are the same as those in Example 1.
[0091] 2) Soaking soybeans in hot water: Soak soybeans at a ratio of raw materials to clear water of 1:4. Adjust the pH of the water to 5.6, heat it to 83°C, and quantitatively add it to the soybeans for about 4 hours. The water absorption rate of soybeans is 1.2 times that of soybeans.
[0092] Comparative Example 6
[0093] Compared with Example 1, Comparative Example 6 is different in step 2), does not contain the first stage, and other steps are the same as those in Example 1.
[0094] 2) Soaking soybeans in hot water: Soak soybeans at a ratio of raw materials to clear water of 1:4. Adjust the pH of the water to 5.5, heat it to 80°C, and quantitatively add it to the soybeans for about 4 hours. The water absorption rate of soybeans is 1.2 times that of soybeans.
[0095] Comparative Example 7
[0096] Compared with Example 1, Comparative Example 7 is different in step 2), and other steps are the same as those in Example 1.
[0097] 2) Soaking beans in hot water: Soak the beans according to the ratio of raw materials to clear water of 1:4;
[0098] A. The first stage: Adjust the pH of the water to 5.6, heat it to 93 degrees, put the weighed soybeans into the hot water and start soaking for 1 hour, then drain the water.
[0099] B. The second stage: Adjust the pH of the water to 5.5, heat it to 80 °C, quantitatively add it to the soybeans in the first stage, and soak for 2.0 hours. The total soaking time is about 3 hours, and the water absorption rate of the beans is 1.2 times that of the soybeans.
[0100] Comparative Example 8
[0101] Compared with Example 1, the difference in Comparative Example 8 is that step 2) is different, and other steps are the same as those in Example 1.
[0102] 2) Soaking beans in hot water: Soak the beans according to the ratio of raw materials to clear water of 1:4:
[0103] A. The first stage: Adjust the pH of the water to 7.0, heat it to 83 °C, put the weighed soybeans into the hot water and start soaking for 1 hour, then drain the water;
[0104] B. The second stage: Adjust the pH of the water to 7.0, heat it to 80 °C, quantitatively add it to the soybeans in the first stage, and soak for 2 hours. The total soaking time is 3 hours, and the water absorption rate of the beans is 1.2 times that of the soybeans.
[0105] Test Example
[0106] Measure the rate of stiff beans and the yield of tofu embryos (soybeans: milk embryos) in the methods of the above Examples 1-6 and Comparative Examples 1-8.
[0107] Measure the physical and chemical properties of the fermented bean curd prepared in the above Examples 1-6 and Comparative Examples 1-8, including amino acids, sodium chloride, total acid, coliform bacteria, color, brightness, body state, and the situation of rose aroma.
[0108] The measurement methods of each parameter are as follows:
[0109] (1) Amino acids: Measured with reference to the first method of GB5009.235-2016;
[0110] (2) Sodium chloride: Measured with reference to the third method of GB 5009.44-2016;
[0111] (3) Total acid: Measured with reference to SB / T10170-2007;
[0112] (3) Coliform bacteria: Measured with reference to CB / T-4789.3-2010;
[0113] (4) Color, brightness, shape, and aroma of roses:
[0114] The sensory experience is evaluated by 10 people with sensory experience on a scale of 1-10, and the arithmetic mean is taken. The higher the score, the better the sensory effect of the content.
[0115] The results are shown in Table 1.
[0116] Table 1
[0117]
[0118]
[0119]
[0120] As can be seen from the data in Table 1, by using the slightly acidic high-temperature bean soaking process of Examples 1 to 6, the mature soybean particles are fully soaked, absorb water appropriately and fully, the beans are crisp but not soft, the soaking time is short, the beans are sweet, and there is no other odor. The process of the present application can shorten the soaking time, solve the problem of the stiff bean rate caused by natural soaking, and reduce the stiff bean rate from about 3% to below 0.05%, thereby increasing the protein dissolution rate and thus increasing the soybean output rate; in addition, the above-mentioned soaking process can also reduce the contamination of microorganisms during the soaking process, and steadily improve the quality of fermented bean curd products.
[0121] Compared to Comparative Examples 1-4, the soybean soaking process used in Examples 1-6 of the present application eliminates the shortcomings of the traditional old method, which is natural water absorption, unstable soaking time, and human experience control. By soaking the soybeans at high temperature, the soybeans are fully soaked and soft, and the pulp is easy to grind. The protein and other nutrients in the soybeans are easily extracted, thereby improving the soybean yield.
[0122] The bean soaking processes of Comparative Examples 5 and 6 do not contain the first stage or the second stage respectively. Comparative Example 5 shows that the soaking time is longer, and the physical and chemical properties and sensory effects of fermented bean curd are not as good as those of Examples 1 to 6; Comparative Example 6 shows that the soaked soybean particles are not fully soaked, the water absorption is average, and one-third of the beans are fully cooked, and the protein is denatured.
[0123] In the first stage of the bean soaking process of Comparative Example 7, the temperature is relatively high, the soaked soybean particles are not fully soaked, the water absorption is average, and two-thirds of the beans are fully cooked, the protein is denatured, and the soaking time is short.
[0124] In the first stage of the soaking process of Comparative Example 8, the temperature was high, the soaked soybeans were not fully soaked, the water absorption was average, and two-thirds of the soybeans were fully cooked, the protein was denatured, and the soaking time was short. The water pH was high, and the curd had a slightly astringent aftertaste.
[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.
Claims
1. A hot water soaked soybean process, characterized in that It includes the following steps: S1. Adjust the pH value of water to 5.5 - 6.0, heat it to 80 - 85 °C, then soak soybeans in the treated water, and then drain the water; S2. Adjust the pH value of water to 5.5 - 6.0, heat it to 70 °C - 85 °C, and then add the water to soak the soybeans treated in step S1.
2. A method for producing fermented bean curd, characterized in that, It includes the following steps: 1) Adjust the pH value of water to 5.5 - 6.0, heat it to 80 - 85 °C, then soak soybeans in the treated water, and then drain the water; 2) Adjust the pH value of water to 5.5 - 6.0, heat it to 70 °C - 85 °C, and then add the water to soak the soybeans treated in step 1); 3) Grind, filter, separate the pulp from the residue of the soybeans treated in step 2), and then cook the pulp; 4) Mix the cooked soybean milk with a coagulant, perform curdling and waiting, pressing, cutting the curd embryo, then ferment and pickle the curd embryo with Mucor to obtain a salty embryo, pour the preserved bean curd soup into the salty embryo for post-fermentation to obtain preserved bean curd.
3. The method for producing fermented bean curd according to claim 2, wherein, The ratio of the weight of the soybeans to the total weight of water is 1:(3.5 - 4.5).
4. The method for producing fermented bean curd according to claim 2, characterized in that In step 1), the soaking time is 0.5 - 1 h; in step 2), the soaking time is 1 - 2 h.
5. The method for producing fermented bean curd according to claim 2, characterized in that, In step 3), the cooking temperature of the pulp is 98 - 105 °C, and the cooking time is 1 - 2 min.
6. The method for producing fermented bean curd according to claim 2, characterized in that, In step 4), the conditions for Mucor fermentation are: the fermentation time is 34 - 36 h, and the fermentation temperature is 31 - 33 °C.
7. The method for producing fermented bean curd according to claim 2, characterized in that, In step 4), the pickling time is 6 - 8 h.
8. The method for producing fermented bean curd according to claim 2, characterized in that, In step 4), the post-fermentation time is 40 - 60 days.
9. The method for producing fermented bean curd according to claim 2, wherein, The preserved bean curd soup includes edible alcohol, edible refined salt and water, and the mass ratio of edible alcohol, edible refined salt and water is 50:8:
42.
10. The method for producing fermented bean curd according to claim 2, characterized in that, The mass ratio of the soybean milk to the coagulant is 1:(0.1 - 0.15).