Method for brewing soy sauce

Abstract

The invention provides a soy sauce brewing method which comprises the following steps: 1) making koji to obtain a koji material; 2) mixing the koji material with first salt water to obtain a primary mixed material liquid; (3) mixing the primary mixed material liquid with second saline water to obtain secondary mixed material liquid; 4) conveying the secondary mixed material liquid to a fermentation device; and 5) fermenting. The method increases the total nitrogen utilization rate of the soy sauce to 87% or above, and is low in cost, efficient and compatible.

Description

Technical Field

[0001] The invention belongs to the technical field of soy sauce brewing, and particularly relates to a method for brewing soy sauce. Background Art

[0002] In soy sauce brewing, total nitrogen utilization is the core indicator to measure the conversion of raw protein into soluble nitrogen-containing substances, and can be used to measure the technical level and management level of soy sauce production. How to improve total nitrogen utilization has always been a technical problem that the soy sauce brewing industry is committed to solving. Summary of the invention

[0003] The invention provides a method for brewing soy sauce. The method improves the total nitrogen utilization rate of the soy sauce to more than 87% by regulating the brine osmotic gradient, optimizing the mixing method and pumping parameters in the yellowing stage, has low cost and high efficiency and compatibility.

[0004] The present invention provides a method for brewing soy sauce, comprising:

[0005] 1) making koji to obtain koji material;

[0006] 2) mixing the koji material with the first brine to obtain a primary mixed liquid;

[0007] 3) mixing the primary mixed liquid with the second brine to obtain a secondary mixed liquid;

[0008] 4) transporting the secondary mixed liquid to a fermentation device;

[0009] 5) Fermentation.

[0010] In certain embodiments, the first brine is an aqueous sodium chloride solution having a concentration of 14-16° Bé. In certain embodiments, the first brine is an aqueous sodium chloride solution having a concentration of 14.5-16° Bé. In certain embodiments, the first brine is an aqueous sodium chloride solution having a concentration of 14.5-15° Bé. In certain embodiments, the first brine is an aqueous sodium chloride solution having a concentration of 14.6° Bé or 15° Bé.

[0011] In certain embodiments, the second brine is an aqueous sodium chloride solution at a concentration of 22-24° Bé containing 0.1%-0.2% by weight sodium lactate. In certain embodiments, the second brine is an aqueous sodium chloride solution at a concentration of 22.5-23.5° Bé containing 0.12%-0.18% by weight sodium lactate. In certain embodiments, the second brine is an aqueous sodium chloride solution at a concentration of 23-23.5° Bé containing 0.12% by weight sodium lactate.

[0012] In certain embodiments, the weight ratio of koji material to the first brine is (0.9 - 1.3):1.0. In certain embodiments, the weight ratio of koji material to the first brine is (1.0 - 1.2):1.0. In certain embodiments, the weight ratio of koji material to the first brine is (1.0 - 1.1):1.0.

[0013] In certain embodiments, the weight ratio of the second brine to the koji material is (0.2 - 0.6):1.0. In certain embodiments, the weight ratio of the second brine to the koji material is (0.3 - 0.5):1.0. In certain embodiments, the weight ratio of the second brine to the koji material is (0.4 - 0.5):1.0.

[0014] In certain embodiments, the koji material and the first brine are mixed by vortex to obtain a primary mixture liquid.

[0015] In certain embodiments, the primary mixture liquid and the second brine are mixed by vortex while using ultrasonic wave-assisted mixing to obtain a secondary mixture liquid.

[0016] In certain embodiments, the koji material and the first brine are mixed in a screw conveyor. In certain embodiments, the koji material and the first brine are mixed in the screw conveyor at a rotation speed of 20 - 30 rpm for 30 - 60 seconds.

[0017] In certain embodiments, the primary mixture liquid and the second brine are mixed in a screw conveyor. In certain embodiments, the primary mixture liquid and the second brine are mixed in the screw conveyor at a rotation speed of 20 - 30 rpm for 30 - 60 seconds.

[0018] In certain embodiments, the ultrasonic wave frequency is such that the primary mixture liquid and the second brine are mixed in a screw conveyor while using ultrasonic wave-assisted mixing with a frequency of 20 - 30 kHz and a power of 150 - 300 W.

[0019] In certain embodiments, the secondary mixture liquid is transported to a fermentation device by a rotor pump, and the outlet pressure of the rotor pump is less than or equal to 0.3 MPa.

[0020] In certain embodiments, the first brine is preheated to 35 - 40 °C before being mixed with the koji material. In certain embodiments, the first brine is preheated to 36 - 38 °C before being mixed with the koji material. In certain embodiments, the first brine is preheated to 37 °C before being mixed with the koji material. In certain embodiments, the second brine is preheated to 35 - 40 °C before being mixed with the primary mixture liquid. In certain embodiments, the second brine is preheated to 36 - 38 °C before being mixed with the koji material. In certain embodiments, the second brine is preheated to 37 °C before being mixed with the koji material.

[0021] In certain embodiments, koji making includes:

[0022] 1-1) Mix the cooked soybeans, flour, and Aspergillus oryzae strain to obtain a mixture;

[0023] 1-2) Incubate the obtained mixture at a temperature of 28°C - 38°C and a fan frequency of 20 - 50 Hz for 40 - 46 hours to obtain koji material,

[0024] wherein the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:(2.5 - 3.5):(0.007 - 0.015).

[0025] In certain embodiments, the fermentation includes:

[0026] 5-1) Conduct primary fermentation at a temperature of 32 - 38°C for 50 - 70 days, preferably 60 days, to obtain the first oil;

[0027] 5-2) Add 1.2 - 2 times the weight of the third brine to the mash remaining after discharging the first oil, mix, and conduct secondary fermentation for 7 - 14 days, preferably 10 days, to obtain the second oil,

[0028] In certain embodiments, the third brine is an aqueous sodium chloride solution with a concentration of 20 - 25°Bé, preferably an aqueous sodium chloride solution with a concentration of 23°Bé.

[0029] The present invention also provides a soy sauce obtained by the method for brewing soy sauce described in the present invention.

[0030] In the present invention, brine refers to an aqueous solution of sodium chloride.

[0031] In the present invention, the concentration unit of brine is Baumé (°Bé), and the degree obtained by dipping a Baumé hydrometer into the measured brine is the Baumé degree.

[0032] In the present invention, the "yellowing stage" refers to the stage where the koji material is mixed with brine and then pumped into the fermentation tank.

[0033] Advantages of the present invention

[0034] The method for brewing soy sauce provided by the present invention can increase the total nitrogen utilization rate of soy sauce to more than 87%, while having low cost and being highly compatible. Detailed embodiments

[0035] The following further illustrates the substantial content of the present invention in combination with specific embodiments of the present invention. It should be understood that the following embodiments are only used to illustrate the present invention, but do not limit the protection scope of the present invention.

[0036] Although many of the materials and operating methods used in the following embodiments are well known in the art, the present invention is still described in as much detail as possible herein. Those skilled in the art will understand that if not otherwise specified, the materials and operating methods used in the following embodiments are well known in the art, and the raw materials without indicating the manufacturer can be obtained as conventional products through commercial purchase. The brine used in the embodiments of the present invention is an aqueous sodium chloride solution

[0037] Example 1

[0038] Step 1. Soybean pretreatment

[0039] After removing impurities, weighing, soaking, and crushing soybeans, continuous cooking is carried out in a continuous cooker to obtain cooked soybeans

[0040] Step 2. Mixing and koji making

[0041] Take flour, Aspergillus oryzae strain and mix them evenly with the cooked soybeans obtained in Step 1, and send them to a disk koji maker. Among them, the fan frequency is 20 - 50 Hz, the culture temperature is 28℃ - 38℃, the culture time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. Koji material is obtained through cultivation

[0042] Step 3. Yellowing

[0043] Step 3.1 Gradient brine preparation and pretreatment

[0044] The first brine: with a concentration of 15.0°Bé, preheated to 37℃, and stored in a heat preservation tank for standby

[0045] The second brine: with a concentration of 23.0°Bé, adding 0.12 wt% sodium lactate (pH buffer), preheated to 37℃, and stored in a heat preservation tank for standby

[0046] Step 3.2 Preparation of primary mixed liquor

[0047] Add the koji material obtained in Step 2 and the first brine dynamically to the first spiral auger for vortex mixing to obtain the primary mixed liquor. Among them, the weight ratio of the koji material to the first brine is 1.1:1.0, the auger rotation speed is 25 rpm, and the stirring time is 45 s

[0048] Step 3.3 Preparation of secondary mixed material

[0049] Transfer the primary mixed liquor to the second spiral auger under the pushing action of the first spiral auger, and carry out vortex mixing with the second brine. At the same time, ultrasonic assistance mixing is carried out to uniformly infiltrate the koji material particles to obtain the secondary mixed liquor. Among them, the weight ratio of the second brine to the koji material is 0.4:1.0, the auger rotation speed is 25 rpm, the stirring time is 45 s, the ultrasonic frequency is 25 kHz, and the power is 200 W

[0050] Step 3.4 Send to the fermentation and insulation tank

[0051] Use a rotor pump to transfer the secondary mixture liquid to the fermentation and insulation tank, where the outlet pressure of the rotor pump ≤ 0.3 MPa.

[0052] Step 4. Primary fermentation:

[0053] The temperature of the primary fermentation is controlled at 32 - 38 °C throughout the process, and the fermentation lasts for 60 days. Then, release the oil layer liquid from the bottom of the fermentation tank and filter it using a filter screen to obtain the first oil. Stirring is prohibited before releasing the first oil to facilitate the gradual stratification of the oil and the mash.

[0054] Step 5. Secondary fermentation:

[0055] In the mash remaining after releasing the first oil, add 1.5 times the weight of the third brine with a concentration of 23 °Bé, stir evenly and continue fermentation for 10 days, and obtain the second oil after pressing.

[0056] Example 2

[0057] Step 1. Soybean pretreatment

[0058] After removing impurities, weighing, soaking, and crushing soybeans, conduct continuous cooking in a continuous cooker to obtain cooked soybeans.

[0059] Step 2. Mixing and koji making

[0060] Mix flour, Aspergillus oryzae strain, and the cooked soybeans obtained in Step 1 evenly, and send them to a disk koji maker. Among them, the fan frequency is 20 - 50 Hz, the cultivation temperature is 28 °C - 38 °C, the cultivation time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. Cultivate to obtain koji material.

[0061] Step 3. Yellowing

[0062] Step 3.1 Gradient brine preparation and pretreatment

[0063] The first brine: concentration 14.6 °Bé, preheated to 37 °C, stored in a heat preservation tank for standby;

[0064] The second brine: concentration 23.3 °Bé, add 0.12 wt% sodium lactate (pH buffer), preheated to 37 °C, stored in a heat preservation tank for standby.

[0065] Step 3.2 Preparation of the primary mixture liquid

[0066] Dynamically add the koji material obtained in Step 2 and the first brine to the first spiral auger for vortex mixing to obtain the primary mixture liquid. Among them, the mass ratio of the koji material to the first brine is 1.0:1.0, the auger rotation speed is 25 rpm, and the stirring time is 50 s.

[0067] Step 3.3 Preparation of secondary mixed material

[0068] The primary mixed material liquid is transferred to the second screw conveyor under the pushing action of the first screw conveyor, and is vortex-mixed with the second brine. At the same time, ultrasonic-assisted mixing is carried out to uniformly infiltrate the koji particles, obtaining the secondary mixed material liquid. The weight ratio of the second brine to the koji is 0.5:1.0, the screw conveyor rotation speed is 25 rpm, the stirring time is 50 s, the ultrasonic frequency is 25 kHz, and the power is 200 W.

[0069] Step 3.4 Pumping to the fermentation heat preservation tank

[0070] The secondary mixed material liquid is pumped into the fermentation heat preservation tank by a rotor pump, and the outlet pressure of the rotor pump is ≤ 0.3 MPa.

[0071] Step 4. Primary fermentation

[0072] The temperature of the primary fermentation is controlled at 32 - 38 °C throughout the process, and the fermentation lasts for 60 days. Then, the oil layer liquid is discharged from the bottom of the fermentation tank and filtered using a filter screen to obtain the first oil. Stirring is prohibited before discharging the first oil to facilitate the gradual stratification of the oil and the mash.

[0073] Step 5. Secondary fermentation

[0074] In the mash remaining after discharging the first oil, 1.5 times the weight of the third brine is added. The concentration of the third brine is 23 °Bé. After stirring evenly, fermentation continues for 10 days, and the second oil is obtained after pressing.

[0075] Comparative Example 1

[0076] Step 1. Pretreatment of soybeans

[0077] After removing impurities, weighing, soaking, and crushing soybeans, continuous cooking is carried out in a continuous cooker to obtain cooked soybeans.

[0078] Step 2. Mixing and koji making

[0079] Take flour, Aspergillus oryzae strain and the cooked soybeans obtained in Step 1, mix them evenly, and send them to a disk koji maker. The fan frequency is 20 - 50 Hz, the cultivation temperature is 28 °C - 38 °C, the cultivation time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. The koji material is obtained through cultivation.

[0080] Step 3. Yellowing

[0081] Step 3.1 Brine preparation

[0082] Prepare the fourth brine with a concentration of 18.6 °Bé, preheat it to 37 °C, and store it in a heat preservation tank for standby.

[0083] Step 3.2 Preparation of primary mixed material liquid

[0084] The koji material obtained in Step 2 and the fourth brine are dynamically added to the first spiral auger and mixed by eddy current to obtain a primary mixed material liquid. The weight ratio of the koji material to the fourth brine is 1.1:1.0, the auger rotation speed is 25 rpm, and the stirring time is 45 s.

[0085] Step 3.3 Preparation of the secondary mixed material

[0086] The primary mixed material liquid is transferred to the second spiral auger under the pushing action of the auger and mixed with the fourth brine by eddy current. At the same time, ultrasonic-assisted mixing is carried out to uniformly infiltrate the koji material particles to obtain a secondary mixed material liquid. The weight ratio of the brine to the koji material is 0.4:1.0, the auger rotation speed is 25 rpm, the stirring time is 45 s, the ultrasonic frequency is 25 kHz, and the power is 200 W.

[0087] Step 3.4 Pumping to the fermentation insulation tank

[0088] The secondary mixed material liquid is pumped to the fermentation insulation tank by a rotor pump, and the outlet pressure of the rotor pump is ≤ 0.3 MPa.

[0089] Step 4. Primary fermentation

[0090] The temperature of the primary fermentation is controlled at 32 - 38 °C throughout the process, and the fermentation lasts for 60 days. Then, the oil layer liquid is discharged from the bottom of the fermentation tank and filtered using a filter screen to obtain the first oil. Stirring is prohibited before discharging the first oil to facilitate the gradual stratification of the oil and the mash.

[0091] Step 5. Secondary fermentation:

[0092] In the mash remaining after discharging the first oil, 1.5 times the weight of the third brine is added. The concentration of the third brine is 23 °Bé. After stirring evenly, fermentation continues for 10 days, and the second oil is obtained after pressing.

[0093] Comparative Example 2

[0094] Step 1. Pretreatment of soybeans

[0095] After removing impurities, weighing, soaking, and crushing the soybeans, continuous cooking is carried out in a continuous cooking machine to obtain cooked soybeans.

[0096] Step 2. Mixing and koji making

[0097] Take flour, Aspergillus oryzae strain and the cooked soybeans obtained in Step 1, mix them evenly, and send them to a disk koji making machine. The fan frequency is 20 - 50 Hz, the cultivation temperature is 28 °C - 38 °C, the cultivation time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. Koji material is obtained through cultivation.

[0098] Step 3. Yellowing

[0099] Step 3.1 Gradient brine preparation and pretreatment

[0100] The first brine: with a concentration of 15.0°Bé, preheated to 37°C, and stored in a heat-insulated tank for standby;

[0101] The second brine: with a concentration of 23.0°Bé, adding 0.12 wt% sodium lactate (pH buffer), preheated to 37°C, and stored in a heat-insulated tank for standby.

[0102] Step 3.2 Preparation of the primary mixed material liquid

[0103] The koji material obtained in Step 2 and the first brine are dynamically added to the first screw conveyor and mixed by eddy current to obtain the primary mixed material liquid. The weight ratio of the koji material to the first brine is 1.1:1.0, the screw conveyor speed is 25 rpm, and the stirring time is 45 s.

[0104] Step 3.3 Preparation of the secondary mixed material

[0105] The primary mixed material liquid is transferred to the second screw conveyor under the pushing action of the first screw conveyor and mixed by eddy current with the second brine, and the koji material particles are evenly wetted to obtain the secondary mixed material liquid. The weight ratio of the second brine to the koji material is 0.4:1.0, the screw conveyor speed is 25 rpm, and the stirring time is 45 s.

[0106] Step 3.4 Pumping to the fermentation heat-insulated tank

[0107] The secondary mixed material liquid is pumped to the fermentation heat-insulated tank by a rotor pump, and the outlet pressure of the rotor pump ≤ 0.3 MPa.

[0108] Step 4. Primary fermentation

[0109] The temperature of the primary fermentation is controlled at 32 - 38°C throughout the process, fermented for 60 days, and then the oil layer liquid is discharged from the bottom of the fermentation tank and filtered using a filter screen to obtain the first oil. Stirring is prohibited before discharging the first oil to facilitate the gradual stratification of the oil and the mash.

[0110] Step 5. Secondary fermentation

[0111] In the mash remaining after discharging the first oil, 1.5 times the weight of the third brine is added. The concentration of the third brine is 23°Bé, stirred evenly and continue to ferment for 10 days, and the second oil is obtained after pressing.

[0112] Comparative Example 3

[0113] Step 1. Soybean pretreatment

[0114] After removing impurities, weighing, soaking, and crushing the soybeans, continuous cooking is carried out in a continuous cooker to obtain cooked soybeans.

[0115] Step 2. Mixing and koji making

[0116] Mix the flour, Aspergillus oryzae strain, and the cooked soybeans obtained in Step 1 evenly, and send them to a disk koji-making process. The frequency of the blower is 20 - 50 Hz, the culture temperature is 28°C - 38°C, the culture time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. The koji material is obtained through cultivation.

[0117] Step 3. Yellowing

[0118] Step 3.1 Preparation and pretreatment of gradient brine

[0119] The first brine: with a concentration of 15.0°Bé, preheated to 37°C, and stored in a heat-insulated tank for standby;

[0120] The second brine: with a concentration of 23.0°Bé, adding 0.12 wt% sodium lactate (pH buffer), preheated to 37°C, and stored in a heat-insulated tank for standby.

[0121] Step 3.2 Preparation of the primary mixed liquor

[0122] Add the koji material obtained in Step 2 and the first brine dynamically to the first screw conveyor, and mix them by eddy current to obtain the primary mixed liquor. The weight ratio of the koji material to the first brine is 1.1:1.0, the screw conveyor speed is 25 rpm, and the stirring time is 45 s.

[0123] Step 3.3 Preparation of the secondary mixed material

[0124] Transfer the primary mixed liquor to the second screw conveyor under the pushing action of the first screw conveyor, and mix it with the second brine by eddy current. At the same time, assist the mixing with ultrasonic waves to uniformly infiltrate the koji material particles, and obtain the secondary mixed liquor. The weight ratio of the second brine to the koji material is 0.4:1.0, the screw conveyor speed is 25 rpm, the stirring time is 45 s, the ultrasonic frequency is 25 kHz, and the power is 200 W.

[0125] Step 3.4 Pump to the fermentation heat-insulated tank

[0126] Transfer the secondary mixed liquor to the fermentation heat-insulated tank with a rotor pump, and the outlet pressure of the rotor pump is 0.5 - 0.7 MPa.

[0127] Step 4. Primary fermentation:

[0128] The temperature of the primary fermentation is controlled at 32 - 38°C throughout the process, and the fermentation lasts for 60 days. Then, release the oil layer liquid from the bottom of the fermentation tank and filter it with a filter screen to obtain the first oil. Stirring is prohibited before releasing the first oil to facilitate the gradual stratification of the oil and the mash.

[0129] Step 5. Secondary fermentation:

[0130] In the mash remaining after discharging the first oil, add third brine with a weight 1.5 times that of the mash. The concentration of the third brine is 23°Bé. Stir evenly and continue fermentation for 10 days. After pressing, the second oil is obtained.

[0131] Comparative Example 4

[0132] Step 1. Soybean pretreatment

[0133] After removing impurities, weighing, soaking, and crushing soybeans, conduct continuous cooking in a continuous cooker to obtain cooked soybeans.

[0134] Step 2. Mixing and koji making

[0135] Mix flour, Aspergillus oryzae strain evenly with the cooked soybeans obtained in Step 1, and send them to a disk koji maker. The frequency of the fan is 20 - 50 Hz, the cultivation temperature is 28°C - 38°C, the cultivation time is 40 - 46 h, and the weight ratio of soybeans, flour, and Aspergillus oryzae strain is 7:3:0.01. Koji material is obtained through cultivation.

[0136] Step 3. Yellowing

[0137] Step 3.1 Brine preparation

[0138] Prepare fourth brine with a concentration of 18.6°Bé, preheat it to 37°C, and store it in a heat preservation tank for standby.

[0139] Step 3.2 Preparation of mixed material liquid

[0140] Dynamically add the koji material obtained in Step 2 and the fourth brine to the first spiral auger for vortex mixing to obtain a mixed material liquid. The weight ratio of the koji material to the fourth brine is 1.5:1.0, the rotation speed of the auger is 30 rpm, and the stirring time is 50 s.

[0141] Step 3.3 Pump to the fermentation heat preservation tank

[0142] Transport the mixed material liquid to the fermentation heat preservation tank with a rotor pump. The outlet pressure of the rotor pump is 0.4 - 0.6 MPa.

[0143] Step 4. Primary fermentation:

[0144] The temperature of the primary fermentation is controlled at 32 - 38°C throughout the process, and fermentation lasts for 60 days. Then, release the oil layer liquid from the bottom of the fermentation tank and filter it with a filter screen to obtain the first oil. Stirring is prohibited before discharging the first oil to facilitate the gradual stratification of the oil and the mash.

[0145] Step 5. Secondary fermentation:

[0146] In the mash remaining after discharging the first oil, add third brine with a weight 1.5 times that of the mash. The concentration of the third brine is 23°Bé. Stir evenly and continue fermentation for 10 days. After pressing, the second oil is obtained.

[0147] Index Test

[0148] The various indexes of the first oil and the second oil in Examples 1-2 and Comparative Examples 1-4 were tested. The test methods are as follows:

[0149] 1. Total nitrogen

[0150] Total nitrogen is the sum of organic nitrogen and inorganic nitrogen in soy sauce, reflecting the nutritional value and fermentation degree of soy sauce. The detection method refers to GB / T 18186-2000.

[0151] 2. Amino acid nitrogen

[0152] Amino acid nitrogen refers to the content of nitrogen element in the form of amino acids and is the core index to measure the umami taste and quality of soy sauce. The detection method refers to GB 5009.235-2016.

[0153] 3. Total nitrogen utilization rate of soy sauce

[0154] The total nitrogen utilization rate of soy sauce refers to the ratio of the total amount of total nitrogen in soy sauce to the total amount of protein in raw materials, which is used to measure the technical level and management level of soy sauce production. The detection method of raw material protein refers to GB 5009.5-2016.

[0155] 4. Judgment criteria for the taste of soy sauce:

[0156] The score is from 1 to 5 points. The higher the score, the better the umami taste and the richer and more coordinated the taste.

[0157] Table 1

[0158]

[0159]

[0160] The test results are shown in Table 1. It can be seen from Table 1 that:

[0161] (1) The total nitrogen, total nitrogen utilization rate, amino acid nitrogen, and soy sauce flavor score of the first oil and the second oil obtained in Examples 1-2 are significantly higher than those in Comparative Examples 1 and 4, indicating that gradient brine penetration and staged regulation of salt concentration and enzyme activity are beneficial to reducing the inhibition of sudden osmotic pressure change on protein extraction and achieving the goal of improving the total nitrogen utilization rate and soy sauce flavor.

[0162] (2) The total nitrogen, total nitrogen utilization rate, amino acid nitrogen, and soy sauce flavor score of the first oil and the second oil in Examples 1-2 are significantly higher than those in Comparative Examples 2 and 4, indicating that using ultrasonic-assisted eddy mixing can break through the limitations of traditional static infiltration, further improve the uniformity of the liquid-solid mixture, enhance the accessibility of protease, improve the nitrogen dissolution efficiency, and achieve the goal of improving the total nitrogen utilization rate and soy sauce flavor.

[0163] (3) The total nitrogen, total nitrogen utilization rate, amino acid nitrogen, and soy sauce flavor score of the first oil and the second oil in Examples 1-2 are significantly higher than those in Comparative Example 3 and Comparative Example 4, indicating that low-pressure transportation can reduce the damage of mechanical shear to the enzyme-substrate complex, reduce nitrogen loss, and achieve the goal of improving the total nitrogen utilization rate and soy sauce flavor.

[0164] Although the specific embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and substitutions can be made to those details based on all the teachings that have been disclosed, and such changes are within the protection scope of the present invention. The entire scope of the present invention is given by the appended claims and any equivalents thereof.

Claims

1. A method for brewing soy sauce, comprising: 1) making koji to obtain koji material; 2) mixing the koji material with the first brine to obtain a primary mixed liquid; 3) mixing the primary mixed liquid with the second brine to obtain a secondary mixed liquid; 4) transporting the secondary mixed liquid to a fermentation device; 5) Fermentation.

2. The method of claim 2, wherein the first brine is a sodium chloride aqueous solution with a concentration of 14-16° Bé, and the second brine is a sodium chloride aqueous solution with a concentration of 22-24° Bé containing 0.1%-0.2wt% sodium lactate.

3. The method according to claim 1 or 2, wherein the weight ratio of the koji material to the first brine is (0.9-1.3):1.0, and the weight ratio of the second brine to the koji material is (0.2-0.6):1.

0.

4. The method according to any one of claims 1 to 3, wherein the koji material and the first brine are mixed by vortex mixing to obtain a primary mixed liquid.

5. The method according to any one of claims 1 to 4, wherein the primary mixed liquid and the second brine are mixed by vortex mixing and ultrasonic assisted mixing to obtain a secondary mixed liquid.

6. The method according to any one of claims 1 to 5, wherein the koji material is mixed with the first brine in a spiral auger, Preferably, the koji material is mixed with the first brine in a spiral auger at a rotation speed of 20-30 rpm for 30-60 seconds.

7. The method according to any one of claims 1 to 5, wherein the primary mixed liquid is mixed with the second brine in a spiral auger, Preferably, the primary mixed liquid and the second brine are mixed in the auger at a rotation speed of 20-30 rpm for 30-60 seconds.

8. The method of claim 7, wherein the ultrasonic frequency is 20-30 kHz and 150-300 W for the primary mixed liquid and the second brine to be mixed in the spiral auger.

9. The method according to any one of claims 1 to 8, wherein the secondary mixed liquid is transported to the fermentation device by a rotor pump, and the outlet pressure of the rotor pump is less than or equal to 0.3 MPa.

10. The method according to any one of claims 1 to 9, wherein the first brine is preheated to 35-40°C before being mixed with the koji material, and the second brine is preheated to 35-40°C before being mixed with the primary mixed liquid.

11. The method according to any one of claims 1 to 10, wherein the koji making comprises: 1-1) mixing soybean cooked material, flour and Aspergillus oryzae species to obtain a mixture; 1-2) The obtained mixture is cultured for 40-46 hours at a temperature of 28°C-38°C and a fan frequency of 20-50Hz to obtain a koji material. The weight ratio of soybean, flour and Aspergillus oryzae is 7:(2.5-3.5):(0.007-0.0150).

12. The method of any one of claims 1 to 11, wherein the fermentation comprises: 5-1) Performing primary fermentation at a temperature of 32-38°C for 50-70 days to obtain hair oil; 5-2) Add 1.2 to 2 times the weight of the third salt water to the mash left after the first oil is released, mix and perform secondary fermentation. After 7 to 14 days, the second oil is obtained. Preferably, the third brine is a sodium chloride aqueous solution with a concentration of 20-25° Bé, preferably a sodium chloride aqueous solution with a concentration of 23° Bé.

13. A soy sauce obtained by the method according to any one of claims 1 to 12.

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