Preparation method of black bean braising soy sauce

Abstract

The invention relates to the technical field of food processing, and discloses a preparation method of black bean braising soy sauce, and the black bean braising soy sauce comprises the following raw materials in parts by weight: 10-30 parts of red yeast rice saccharification clear liquid, 5-10 parts of red yeast rice wine liquid and 60-85 parts of black bean soy sauce. The raw materials are blended in proportion to prepare the black bean braising soy sauce. The black bean braising soy sauce provided by the invention is high in nutritional value, red and bright in color without blackening, salty, sweet and delicious in taste, strong in body, strong in fragrance, rich in sauce fragrance with bouquet and high in free amino acid content, and has lovastatin with a blood fat reducing function; the caramel-free braised soy sauce does not contain caramel pigments, white granulated sugar and preservatives, so that the caramel color of the braised soy sauce and zero addition of the preservatives are realized, the safety of the braised soy sauce is improved, and meanwhile, the requirements of special crowds with sucrose intolerance and the like are met.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a method for preparing black bean braised soy sauce. Background Art

[0002] Soy sauce is a traditional Chinese liquid condiment. It is reddish-brown in color, has a unique aroma, and tastes delicious. It can stimulate appetite. It is mainly brewed with beans, wheat or bran as raw materials, and water and salt are added. In recent years, the health function of black foods has attracted more and more attention. Among them, black beans are rich in black bean saponins, black bean pigments and other reducing substances, and have obvious antioxidant effects. The Compendium of Materia Medica records: "Black beans enter the spleen and kidney meridians, and have the functions of nourishing the kidney and yin, strengthening the spleen and removing dampness, removing heat and detoxification, promoting diuresis and reducing swelling, and removing wind and removing numbness." Therefore, black bean soy sauce, which is brewed with black beans as raw materials instead of soybeans, has also become a new force in soy sauce products.

[0003] Braised soy sauce, also known as dark soy sauce, is a darker soy sauce, generally used in making braised dishes. Existing braised soy sauce is generally prepared by adding colorants such as caramel color to the original soy sauce. At the same time, in order to ensure that the soy sauce does not deteriorate during the shelf life, preservatives and other additives are also added. However, caramel color is prone to produce 4-methylimidazole harmful substances during the production process, and its safety issues have attracted great attention. In addition, adding too much caramel color will make the soy sauce lose its original flavor and have a "special" and "unpleasant" caramel smell. Summary of the invention

[0004] In view of this, the present invention provides a method for preparing black bean braised soy sauce to solve the safety problem caused by adding caramel pigment and preservatives to the existing braised soy sauce.

[0005] To achieve the above purpose, the technical scheme provided by the present invention is: a method for preparing black bean braised soy sauce, wherein the black bean braised soy sauce comprises the following raw materials in parts by weight: 10-30 parts of red yeast rice saccharification clear liquid, 5-10 parts of red yeast rice wine liquid, and 60-85 parts of black bean soy sauce;

[0006] The red yeast rice saccharification clear solution is prepared by using red yeast rice as a raw material and sequentially undergoing gelatinization, liquefaction, and saccharification steps;

[0007] The red yeast rice wine is prepared by adding red yeast rice saccharification clear liquid as raw material and fermenting it after adding brewer's yeast;

[0008] The black bean soy sauce is made from black beans as raw materials, and is sequentially softened, flattened, moistened with water, steamed, cooled, inoculated with Aspergillus oryzae, made into koji, fermented with salt water, and squeezed.

[0009] The above raw materials are mixed in proportion to prepare the black bean braised soy sauce.

[0010] The invention prepares red yeast rice into red yeast rice saccharification clear liquid and red yeast rice wine liquid and adds them into the soy sauce crude oil, which can not only replace caramel pigment to achieve the coloring effect of braised soy sauce, but also increase the free amino acid content in the soy sauce, reduce the salt content of the soy sauce, and enable the soy sauce to obtain natural antiseptic ability, thereby avoiding the addition of caramel pigment and preservative in the preparation of the braised soy sauce, achieving zero addition of the braised soy sauce, and improving the safety of the braised soy sauce; at the same time, the invention uses black beans as raw materials to ferment and brew the soy sauce crude oil, and utilizes the nutritional value and functionality of the black beans to improve the nutritional value of the braised soy sauce; and adding red yeast rice powder into the salt water for brewing the black bean soy sauce crude oil can further enhance the coloring effect of the soy sauce.

[0011] Furthermore, the black bean braised soy sauce also includes 3-5 parts by weight of starch for adjusting the required viscosity of the braised soy sauce.

[0012] Furthermore, the preparation method of red yeast rice comprises the following steps:

[0013] Step 1, steaming: soak the washed rice for 4-6 hours, drain, and steam at 100-105° C. for 20-30 minutes until the rice grains have no hard core to obtain the rice to be inoculated;

[0014] Step 2, stacking and heating: After the rice to be inoculated is cooled to 40-45°C, Monascus is inoculated and mixed evenly, and then stacked into a pile, wherein the inoculation amount of Monascus is 0.5-1% of the weight of the rice to be inoculated, and after 16-18 hours of stacking and the product temperature rises to 45-50°C, the first koji turning is performed, and the second koji turning is performed 4-6 hours later. After turning the koji, the koji material is flattened for ventilation culture, and the product temperature of the ventilation culture is controlled at 30-32°C;

[0015] Step 3, drying: drying the mature red yeast rice obtained by ventilation culture in step 2 at 20-30°C.

[0016] Furthermore, the method for preparing the red yeast rice saccharification clear solution comprises the following steps:

[0017] Step 1, gelatinization: crush red yeast rice to obtain red yeast rice powder, add the red yeast rice powder into water at a material-water ratio of 1:(2-4), stir evenly, and gelatinize at 90° C. for 20-50 min to obtain a gelatinized liquid;

[0018] Step 2, liquefaction: adjusting the pH of the gelatinized liquid to 5.5±0.2, adding liquefaction enzyme and liquefying at 85-95° C. for 40-70 min to obtain a liquefied liquid, wherein the amount of the liquefaction enzyme added is 0.1-0.3% of the total weight of the gelatinized liquid;

[0019] Step 3, saccharification: lower the temperature of the liquefied liquid to 60°C, adjust the pH to 4.3±0.2, add saccharifying enzyme and saccharify at 55-70°C for 30-50min to obtain the red yeast rice saccharification clear liquid, wherein the amount of the saccharifying enzyme added is 0.1-0.3% of the total weight of the liquefied liquid.

[0020] Furthermore, the red yeast rice wine is prepared by adding brewer's yeast to the red yeast rice saccharification liquid and fermenting for 68-75 hours, and the amount of brewer's yeast added is 1-2‰ of the total weight of the red yeast rice saccharification liquid.

[0021] In some embodiments of the present invention, the sugar content of the red yeast rice saccharification solution is ≥15 Brix.

[0022] In some embodiments of the present invention, the alcohol content of the red yeast rice wine is greater than 10°.

[0023] Furthermore, the preparation method of the black bean soy sauce comprises the following steps:

[0024] Step 1, raw material pretreatment: the raw black beans are de-stoned, impurity-removed, softened, and flattened to obtain black bean flakes;

[0025] Step 2, moistening: soak the black bean flakes in hot water at 80-85° C. for 5-10 minutes, and then heat them to 90-95° C. to obtain a moistening material, wherein the amount of the black bean flakes added is 65-80% of the weight of the hot water;

[0026] Step 3, cooking: using an FM continuous cooking device to cook the moistened material at a temperature of 128-133° C. and a pressure of 0.17-0.20 MPa for 3.5-5 min to obtain a clinker;

[0027] Step 4, cooling, inoculation, and koji making: After the temperature of the clinker is cooled to 40°C, it is mixed with flour in a mass ratio of clinker: flour = (7-9): (3-1), and then Aspergillus oryzae is added and mixed uniformly, and then ventilated and koji is made. The koji making time is 30-36h, and the addition amount of the Aspergillus oryzae is 3-5‰ of the total weight of the clinker and flour mixture;

[0028] Step 5, fermentation: adding the koji material prepared in step 4 to salt water with a mass concentration of 18-23% according to a material-water ratio of 1: (1.9-2.3) for fermentation at a temperature of 30-35°C, adding Saccharomyces cerevisiae for fermentation for 60 days after fermentation for 25-30 days and when the pH drops to 5.0-5.2, the Saccharomyces cerevisiae is added in an amount of 1‰ of the total weight of the koji material and the salt water, and the Saccharomyces cerevisiae is fermented for 60 days at a temperature of 25-30°C for mature fermentation, and the fermentation time of the mature fermentation is 120-180 days;

[0029] Step 7, pressing: pressing the mixed liquid fermented in step 6 to obtain crude oil, and after the crude oil is sterilized at high temperature and heat-precipitated, extracting the supernatant to obtain black bean soy sauce.

[0030] The above technical solution can achieve the following beneficial effects:

[0031] (1) The black bean braised soy sauce provided by the present invention does not contain caramel color, white sugar, or preservatives, thereby achieving zero addition of caramel color and preservatives to the braised soy sauce, thereby improving the safety of the braised soy sauce and also meeting the needs of special groups such as those with sucrose intolerance.

[0032] (2) The black bean braised soy sauce provided by the present invention has high nutritional value, bright red color without blackness, salty, sweet and fresh taste, thick body, rich aroma, strong sauce aroma accompanied by wine aroma, high free amino acid content, and lovastatin with lipid-lowering function. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific examples. It is to be understood that the specific examples are merely exemplary of the present invention and should not be regarded as the entirety of the present invention or as a limitation or restriction to the technical solution of the present invention. Unless otherwise specified, the raw materials used in the specific examples can be obtained through conventional commercial channels.

[0034] The sources of the strains, enzyme preparations, caramel pigments, and preservatives used in the following examples are as follows:

[0035] Monascus liquid - strain MPWC-4, manufacturer: Chengdu Guoniang Food Co., Ltd.;

[0036] Aspergillus oryzae - Shanghai Brewing 3.042 Koji Essence, manufacturer: Shandong Hezhong Kangyuan Biological Co., Ltd.;

[0037] Liquefaction enzyme - acid-resistant high-temperature amylase, manufacturer: Angel Enzyme Co., Ltd.;

[0038] Glucoamylase - GA-150, manufacturer: Qi Enzyme Preparation Co., Ltd.;

[0039] Saccharomyces rouxii - Beina Bio-culture Collection Center, collection number BNCC 336710;

[0040] Caramel color - Manufacturer: Xiangyu Biotechnology Co., Ltd.

[0041] Preservative - potassium sorbate, manufacturer: Jinneng Technology Co., Ltd.;

[0042] High-proof white vinegar - 12° degree, manufacturer: Hengqing Sauce and Vinegar Food Co., Ltd.

[0043] 1. Preparation of Red Yeast Rice

[0044] (1) Steaming: Weigh 500 kg of rice, wash and soak for 6 hours, drain and steam (steam at 100-105° C. for 20-30 minutes until the rice grains have no hard core).

[0045] (2) Stacking and heating: When the steamed rice is cooled to 40-45°C through ventilation, add Monascus liquid with an inoculation rate of 1%. After mixing well, move it into the koji pool for stacking and heating. After 16-18 hours, when the product temperature rises to 45-50°C, turn the koji for the first time. After 5 hours, turn the koji for the second time. After turning the koji, spread the koji material flat for ventilation and cultivation.

[0046] (3) Ventilation culture: The fan automatically blows air and the product temperature is controlled at 30-32°C. After 72 hours, the mycelium grows fully and water is added at intervals until the mycelium gradually invades the center from the surface of the rice grains and turns bright red. When the red pigment penetrates the center by hand, the red yeast rice is mature.

[0047] (4) Drying: Place the mature red yeast rice in a drying room and dry it at a low temperature of 20-30℃.

[0048] 2. Preparation of Red Yeast Rice Saccharification Solution

[0049] (1) Gelatinization: crush red yeast rice into fine powder to obtain red yeast rice flour, add the red yeast rice flour into water at a material-water ratio of 1:2, stir evenly, and gelatinize at 90° C. for 40 min to obtain a gelatinized liquid;

[0050] (2) Liquefaction: After gelatinization, adjust the pH to 5.5±0.05 with high-proof white vinegar, add 0.1% liquefaction enzyme, and liquefy at 90°C for 60 min;

[0051] (3) Saccharification: After liquefaction, the temperature was lowered to 60°C, the pH was adjusted to 4.3±0.05 with high-proof white vinegar, 0.1% saccharifying enzyme was added, and saccharification was carried out at 60°C for 30 min. After that, the red yeast rice saccharification clear liquid (sugar content 18 Brix) was obtained by squeezing.

[0052] 3. Preparation of Red Yeast Rice Wine

[0053] 1.5‰ brewer's yeast was added to the red yeast rice saccharification clear liquid and fermented for 70 hours, and then filtered to obtain red yeast rice wine (alcohol content 12°).

[0054] 4. Preparation of Black Bean Soy Sauce Crude Oil

[0055] (1) Raw material pretreatment: After the black bean raw material is de-stoned and impurities removed, it is softened in a soybean softener for 30-60 seconds and pressed into 3-5 mm thin slices in a flattening machine;

[0056] (2) moistening: soaking the black bean flakes in hot water at 80-85° C. for 5-10 minutes, and then steam heating to 90-95° C. to obtain a moistening material, wherein the amount of the black bean flakes added is 80% of the weight of the hot water;

[0057] (3) Cooking: Cooking the wet material to mature it, using an FM continuous cooking device to cook the wet material at a temperature of 128-133° C. and a pressure of 0.17-0.20 MPa for 3.5-5 minutes to obtain a clinker;

[0058] (4) Cooling and inoculation: After the cooked clinker is rapidly depressurized and cooled to 40° C. by a steel belt cooling device, it is mixed in a ratio of clinker to flour = 7:3 by mass, and then 5‰ of Aspergillus oryzae is added for ventilation and koji making;

[0059] (5) Koji making: The koji material is made into a round koji, and the total koji making time is 30-36 hours (based on the sensory condition of the finished koji material);

[0060] (6) Fermentation: Add 2 times the weight of salt water (mass concentration 23%) to the prepared koji material, and ferment at a controlled temperature of 30-35°C. Ferment for 25-30 days. When the pH drops to 5.2, add 1‰ of Saccharomyces cerevisiae for fermentation. After 60 days, perform mature fermentation at a controlled temperature of 25-30°C. The mature fermentation time is 180 days.

[0061] (7) Oil extraction: The fermented liquid is squeezed to obtain crude oil, which is sterilized at 105° C. for 60 seconds and heat-precipitated at 95° C. for more than 7 days. The supernatant is extracted to obtain black bean soy sauce crude oil.

[0062] Example 1: Preparation of black bean braised soy sauce

[0063] 100g of red yeast rice saccharification clear liquid, 50g of red yeast rice wine liquid and 600g of black bean soy sauce crude oil are mixed, and 30g of starch is added for mixing, and then the mixture is sterilized at 90-100°C for 30min to obtain the desired black bean braised soy sauce.

[0064] Example 2: Preparation of black bean braised soy sauce

[0065] Take 200g of red yeast rice saccharification clear liquid, 100g of 1# red yeast rice wine liquid and 700g of black bean soy sauce crude oil for preparation, add 40g of starch for preparation, and sterilize at 90-100℃ for 30min to obtain the required black bean braised soy sauce.

[0066] Example 3: Preparation of black bean braised soy sauce

[0067] 300g of red yeast rice saccharification clear liquid, 100g of 1# red yeast rice wine liquid and 850g of black bean soy sauce crude oil are mixed, and 50g of starch is added for mixing, and then the mixture is sterilized at 90-100℃ for 30min to obtain the desired black bean braised soy sauce.

[0068] Comparative Example 1:

[0069] 600 g of black bean soy sauce crude oil was mixed with 30 g of starch and sterilized at 90-100° C. for 30 min.

[0070] Comparative Example 2:

[0071] The same as comparative example 1, except that the preparation method of the black bean soy sauce crude oil used is different. When preparing the black bean soy sauce crude oil, the koji is inoculated with a mixed strain of Aspergillus oryzae and Monascus (mass ratio 1:1), and the inoculation amount is 5‰.

[0072] Comparative Example 3:

[0073] The same as Example 1, except that the preparation method of the black bean soy sauce crude oil is different. The brine used for fermentation in the preparation of the black bean soy sauce crude oil is a brine containing red yeast rice powder, and the brine containing red yeast rice powder is obtained by adding red yeast rice powder (addition amount 1%) to brine with a mass concentration of 23% and then controlling the temperature at 50° C. for 5 days.

[0074] Comparative Example 4:

[0075] 100 g of red yeast rice saccharification clear liquid and 600 g of black bean soy sauce crude oil were mixed, and 30 g of starch was added for mixing, and then sterilized at 90-100° C. for 30 min.

[0076] Comparative Example 5:

[0077] Take 600g of black bean soy sauce crude oil, add 20% caramel coloring, and sterilize at 90-100℃ for 30min.

[0078] Comparative Example 6:

[0079] The same as comparative example 4, except that 0.9‰ of a preservative (potassium sorbate) was added for preparation.

[0080] Comparative Example 7:

[0081] Commercially available braised soy sauce (Sichuan braised soy sauce sold by Chengdu Guoniang Food Co., Ltd., the raw materials include water, caramel color, edible salt, non-GMO defatted soybeans, wheat, wheat bran, monosodium glutamate, disodium ribonucleotides, and sucralose).

[0082] Comparative evaluation analysis:

[0083] The soy sauces of the above-mentioned embodiment and comparative example were tested for the following indicators, and the results are shown in Table 1.

[0084] 1. Free amino acid content: refer to the method of "Quality Analysis of 13 Commercially Available Original Brewed Soy Sauces" by Zhong Xiaoting et al. for amino acid sample pretreatment and determination.

[0085] 2. Color rate: Determine it according to the soy sauce color rate determination method in "Study on Thermal Stability of Ordinary Caramel Color in Dark Soy Sauce" by Xu Yi et al.

[0086] 3. Red index: Determine with reference to the soy sauce red index determination method in "Study on Thermal Stability of Ordinary Caramel Color in Dark Soy Sauce" by Xu Yi et al.

[0087] 4. Salt content: Determine according to GB 18186-2000.

[0088] 5. Anticorrosiveness: Refer to T / CNFIA 001-2017 and GB 18186-2000 for sensory evaluation of sample shelf life.

[0089] 6. Lovastatin content: Determine according to BJS201710.

[0090] 7. Coloring of braised pork: Use the same method, the same raw materials and ingredients, and equal amounts of the above-mentioned soy sauce to make braised pork separately, and observe the coloring of the braised pork.

[0091] Table 1. Summary of soy sauce index test results

[0092]

[0093] As can be seen from Table 1, compared with Comparative Examples 1 and 2, the black bean braised soy sauce in Examples 1 to 3, to which red yeast rice saccharification clear solution and red yeast rice wine liquid are added, not only increases the free amino acid content, increases the color rate value, reduces the salt content, but also enables the soy sauce to obtain a natural antiseptic ability, and at the same time detects the lovastatin component; and referring to the data of Comparative Examples 1 and 2, it can be seen that the addition of Monascus to the fermentation of black bean crude oil does not contribute much to the improvement of color rate and red index; and referring to the data of Comparative Example 3, in Comparative Example 3, red yeast rice powder is added to the fermentation brine of black bean crude oil, compared In Example 1, the fermented brine without red yeast rice powder has an unsatisfactory coloring effect. Referring to the data of Comparative Example 4, it can be seen that the addition of red yeast rice wine has made a major contribution to the color rate and antiseptic properties of the soy sauce. Compared with the braised soy sauces of Comparative Examples 5 to 7 prepared with caramel color, the black bean braised soy sauces prepared in Examples 1 to 3 not only have higher soy sauce core indicators (free amino acid content) than the soy sauces of the comparative examples, but also have good coloring effects, and at the same time, have lower salt content, do not contain preservatives, and contain lovastatin components with lipid-lowering functions, which are healthier than the soy sauces of the comparative examples.

[0094] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing black bean braised soy sauce, characterized in that: The black bean braised soy sauce comprises the following raw materials in parts by weight: 10-30 parts of red yeast rice saccharification clear liquid, 5-10 parts of red yeast rice wine liquid, and 60-85 parts of black bean soy sauce; The red yeast rice saccharification clear solution is prepared by using red yeast rice as a raw material and sequentially undergoing gelatinization, liquefaction, and saccharification steps; The red yeast rice wine is prepared by adding red yeast rice saccharification clear liquid as raw material and fermenting after adding brewer's yeast; The black bean soy sauce is made from black beans as raw materials, and is sequentially softened, flattened, moistened with water, boiled, cooled, inoculated with Aspergillus oryzae, made into koji, fermented with salt water, and squeezed. The above raw materials are mixed in proportion to prepare the black bean braised soy sauce.

2. A method for preparing black bean braised soy sauce according to claim 1, characterized in that: The black bean braised soy sauce also includes 3-5 parts by weight of starch.

3. A method for preparing black bean braised soy sauce according to claim 1, characterized in that: The preparation method of red yeast rice comprises the following steps: Step 1, steaming: soak the washed rice for 4-6 hours, drain, and steam at 100-105° C. for 20-30 minutes until the rice grains have no hard core to obtain the rice to be inoculated; Step 2, stacking and heating: After the rice to be inoculated is cooled to 40-45°C, Monascus is inoculated and mixed evenly, and then stacked into a pile, wherein the inoculation amount of Monascus is 0.5-1% of the weight of the rice to be inoculated, and after 16-18 hours of stacking and the product temperature rises to 45-50°C, the first koji turning is performed, and the second koji turning is performed 4-6 hours later. After turning the koji, the koji material is flattened for ventilation culture, and the product temperature of the ventilation culture is controlled at 30-32°C; Step 3, drying: drying the mature red yeast rice obtained by ventilation culture in step 2 at 20-30°C.

4. The method for preparing black bean braised soy sauce according to claim 1, wherein: The method for preparing the red yeast rice saccharification clear solution comprises the following steps: Step 1, gelatinization: crush red yeast rice to obtain red yeast rice powder, add the red yeast rice powder into water at a material-water ratio of 1:(2-4), stir evenly, and gelatinize at 90° C. for 20-50 min to obtain a gelatinized liquid; Step 2, liquefaction: adjusting the pH of the gelatinized liquid to 5.5±0.2, adding liquefaction enzyme and liquefying at 85-95° C. for 40-70 min to obtain a liquefied liquid, wherein the amount of the liquefaction enzyme added is 0.1-0.3% of the total weight of the gelatinized liquid; Step 3, saccharification: lower the temperature of the liquefied liquid to 60°C, adjust the pH to 4.3±0.2, add saccharifying enzyme and saccharify at 55-70°C for 30-50min to obtain the red yeast rice saccharification clear liquid, wherein the amount of the saccharifying enzyme added is 0.1-0.3% of the total weight of the liquefied liquid.

5. A method for preparing black bean braised soy sauce according to claim 1 or 4, characterized in that: The sugar content of the red yeast rice saccharification clear liquid is ≥15 Brix.

6. The method for preparing black bean braised soy sauce according to claim 1, characterized in that: The red yeast rice wine is prepared by adding brewer's yeast to the red yeast rice saccharification clear liquid and fermenting for 68-75 hours, and the amount of brewer's yeast added is 1-2‰ of the total weight of the red yeast rice saccharification clear liquid.

7. A method for preparing black bean braised soy sauce according to claim 1 or 6, characterized in that: The alcohol content of the red yeast rice wine is greater than 10°.

8. The method for preparing black bean braised soy sauce according to claim 1, characterized in that: The preparation method of the black bean soy sauce comprises the following steps: Step 1, raw material pretreatment: the raw black beans are de-stoned, impurity-removed, softened, and flattened to obtain black bean flakes; Step 2, moistening: soak the black bean flakes in hot water at 80-85° C. for 5-10 minutes, and then heat them to 90-95° C. to obtain a moistening material, wherein the amount of the black bean flakes added is 65-80% of the weight of the hot water; Step 3, cooking: using an FM continuous cooking device to cook the moistened material at a temperature of 128-133° C. and a pressure of 0.17-0.20 MPa for 3.5-5 min to obtain a clinker; Step 4, cooling, inoculation, and koji making: After the temperature of the clinker is cooled to 40°C, it is mixed with flour in a mass ratio of clinker: flour = (7-9): (3-1), and then Aspergillus oryzae is added and mixed uniformly, and then ventilated and koji is made. The koji making time is 30-36h, and the addition amount of the Aspergillus oryzae is 3-5‰ of the total weight of the clinker and flour mixture; Step 5, fermentation: adding the koji material prepared in step 4 to salt water with a mass concentration of 18-23% according to a material-water ratio of 1: (1.9-2.3) for fermentation at a temperature of 30-35°C, adding Saccharomyces cerevisiae for fermentation for 60 days after fermentation for 25-30 days and when the pH drops to 5.0-5.2, the Saccharomyces cerevisiae is added in an amount of 1‰ of the total weight of the koji material and the salt water, and the Saccharomyces cerevisiae is fermented for 60 days at a temperature of 25-30°C for mature fermentation, and the fermentation time of the mature fermentation is 120-180 days; Step 7, pressing: pressing the mixed liquid fermented in step 6 to obtain crude oil, and after the crude oil is sterilized at high temperature and heat-precipitated, extracting the supernatant to obtain black bean soy sauce.

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