Preparation method of black bean salt-reduced soy sauce without addition

Abstract

The present application belongs to the technical field of brewing fermentation, and discloses a preparation method of black bean salt-reduced soy sauce without addition, comprising the following steps: (1) soaking: soaking black beans in drinking water until there is no white core; (2) steaming and cooking: uniformly mixing and sterilizing roasted wheat and black bean cooked materials to obtain koji material; (3) koji making: mixing the koji material with koji extract to prepare green or light green koji; (4) wine cheese making: steaming roasted wheat, adding root enzyme and yeast to obtain wine cheese; (5) fermentation: preparing preliminary soy sauce mash, adding wine cheese, and inoculating S yeast liquid to obtain fermented mash; (6) squeezing or leaching: squeezing or leaching the fermented mash to collect crude oil; (7) sterilization treatment: high-temperature instant sterilization of the crude oil to obtain salt-reduced black bean soy sauce. The present application starts from the fermentation process, innovates the process conditions, directly produces special-grade black bean soy sauce with reduced salt and sodium, and thus achieves the purpose of increasing nutrition and reducing salt and sodium.

Description

Technical Field

[0001] This invention belongs to the field of brewing and fermentation technology, and in particular, a method for preparing additive-free black bean reduced-sodium soy sauce. Background Technology

[0002] As people's living standards continue to improve, more and more consumers are paying attention to the nutritional value of food. Firstly, the health benefits of black foods have gained increasing attention in recent years. Black beans, in particular, are rich in black bean saponins, black bean pigments, and other reducing substances, exhibiting significant antioxidant effects. The Compendium of Materia Medica records that "black beans enter the spleen and kidney meridians, and have the functions of nourishing the kidneys and yin, strengthening the spleen and promoting diuresis, clearing heat and detoxifying, promoting urination and reducing swelling, and dispelling wind and relieving numbness." Black bean soy sauce has thus become a new force in the soy sauce product market.

[0003] Secondly, numerous studies have confirmed a negative correlation between salt and cardiovascular disease and hypertension, making salt reduction a crucial issue for condiment development. Soy sauce is an indispensable condiment in daily life, and its salt content is increasingly attracting consumer attention. Consequently, soy sauce manufacturers have begun developing low-sodium products. However, most low-sodium soy sauces on the market are blended from crude oil, and due to limitations in testing methods, they only reduce chlorine levels, not sodium. Furthermore, the use of food additives is increasingly drawing consumer attention. Currently, the following technical problems still exist in existing soy sauce production processes:

[0004] (1) Since the production process of soy sauce involves koji making, the distribution of microorganisms in the materials is relatively complex. After the salinity decreases during the fermentation stage, the risk of contamination by miscellaneous bacteria increases, the acidity rises, and it is very easy to become rancid, which seriously contaminates the quality of soy sauce. Therefore, the traditional high-salt dilute state fermentation process cannot achieve the purpose of low-salt fermentation.

[0005] (2) The specific steps for producing high-salt dilute soybean soy sauce are: soaking soybeans, steaming the material in a spherical steaming tank, cooling and inoculating with bacteria, making koji in a koji bed, mixing with brine, fermenting in a constant temperature fermentation tank, pressing and settling, sterilization, and filling. The fermentation cycle is long, requiring 4-6 months, and it occupies fermentation tanks and energy.

[0006] (3) The specific steps of double-fermentation soybean soy sauce are as follows: using the crude oil from normal fermentation as brine, mixing it with the starter culture, and continuing fermentation. At the same time, the dominant bacteria in the crude oil can effectively reduce contamination by miscellaneous bacteria and increase acidity, ensuring the safety of the soy sauce. Double fermentation can effectively increase the content of amino acid nitrogen and total nitrogen. Then, by adding water and blending in the later stage, a reduced-salt soy sauce crude oil is obtained. However, because the effective substances in the soy sauce raw liquid are already saturated, the secondary fermentation results in low raw material utilization, which greatly increases the cost. In addition, the double fermentation method has a long fermentation cycle, long equipment occupation time, and large energy consumption, which also greatly increases the cost.

[0007] Therefore, there is an urgent need for a low-sodium soy sauce production process that can be easily applied by enterprises without altering the main flavor of soy sauce. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing additive-free black bean reduced-sodium soy sauce.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] A method for preparing additive-free, low-sodium black bean soy sauce, the method comprising the following steps:

[0011] (1) Soaking: Soak black beans in drinking water until there is no white core, stir well, and you will get soaked black beans;

[0012] (2) Steaming: Place the soaked black beans from step (1) into a steaming pot, and after venting and draining the air, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no white heart is left, to obtain cooked black beans. Then add roasted wheat and mix it evenly with the cooked black beans. Simmer for 15 minutes to obtain koji.

[0013] (3) Making koji: Cool the koji material that has been simmered in step (2) back to 30-35℃, and then transport it to the koji making equipment to mix with koji extract. The amount of koji extract inoculated is 0.03% to 0.05%. After 40-44 hours of koji making, green or light green koji is produced.

[0014] (4) Making fermented wheat: Steam roasted wheat, inoculate with root enzymes and yeast, ferment at 28°C for 15 days to obtain fermented wheat with an alcohol content ≥12%, and set aside for later use.

[0015] (5) Fermentation: The koji obtained in step (3) and the 16% salt water are placed in a fermentation tank and mixed to obtain the initial soy sauce mash. The initial fermentation temperature is 45-50℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process takes 10-20 days. Add the fermented milk obtained in step (4) at a volume ratio of 100:1 to the initial soy sauce mash and the fermented milk, mix it evenly with the mash, stop the heat preservation, lower the fermentation temperature to 30-35℃, and add S yeast liquid to make the final yeast concentration of the mash ≥10. 4 CFU / ml, continue fermentation for 25-45 days, stirring or aerating daily during this period; each stirring lasts 30 seconds, allowing salt-tolerant yeast to multiply and produce aroma; the entire process takes 45-60 days to obtain flavor-enhancing sauce mash;

[0016] (6) Pressing or leaching: After fermentation is completed, press or leach the flavor-enhancing sauce mash obtained in step (5) and collect the crude oil;

[0017] (7) Sterilization treatment: The crude oil collected in step (6) is sterilized at a high temperature of 121-125℃ to obtain low-sodium black bean soy sauce.

[0018] Furthermore, the mass ratio of black beans to roasted wheat is 700:250.

[0019] Furthermore, in step (5), the volume of brine added is 1.4 to 1.6 times the mass of the fermented product.

[0020] Furthermore, the S yeast liquid in (5) is salt-tolerant Rhus oryzae, and the amount added is such that the final yeast concentration of the fermented mash is ≥10. 4 cfu / ml.

[0021] Furthermore, in step (4), the root enzyme is brewing root enzyme and the yeast is brewing yeast. First, brewing root enzyme is added to the steamed roasted wheat and fermented for 10 days. Then, brewing yeast is added and fermented for 5-10 days until the alcohol content is ≥12℃.

[0022] Furthermore, the mass ratio of roasted wheat: brewing root enzyme: brewing yeast is 10:0.05:0.03.

[0023] Furthermore, the reduced-sodium black bean soy sauce obtained in step (7) has an amino acid nitrogen content ≥0.8g / 100ml and a total nitrogen content of ≥0.8g / 100ml.

[0024] ≥1.5g / 100ml, total acid ≤2.5g / 100ml, protein content up to 10g / 100ml, sugar content 7.6g / 100ml, salt (as Cl-) content ≤13.5g / 100ml, sodium content reduced to 3800mg / 100ml, total bacterial count ≤1000cfu / ml.

[0025] The advantages and positive effects of this invention are as follows:

[0026] 1. This invention starts with the fermentation process and innovates the process conditions to directly produce premium black bean soy sauce with reduced salt and sodium, thereby achieving the goal of increasing nutrition while reducing salt and sodium. This invention uses black beans as the main raw material, adopts high-temperature fermentation, and combines it with the method of adding aroma by fermenting wine mash in the later stage. From the perspective of fermentation, the black bean soy sauce is fermented with reduced salt, so as to achieve the goal of reducing salt soy sauce without adding flavor enhancers, color enhancers or food additives.

[0027] 2. The black bean reduced-sodium soy sauce produced by the method of this invention has an amino acid nitrogen content ≥0.8g / 100ml, total nitrogen content ≥1.5g / 100ml, and total acid content ≤2.5g / 100ml, reaching the level of premium soy sauce. This reduced-sodium soy sauce product uses black beans and roasted wheat as the main raw materials. Compared with commercially available reduced-sodium soy sauce, it has the advantages of lower equipment investment, no additional energy consumption, and a shorter fermentation cycle, which can greatly reduce costs. Moreover, it has a rich soy sauce aroma and ester aroma, with both caramel and alcohol ester aromas.

[0028] 3. Because black beans are rich in reducing substances such as black bean saponins and black bean pigments, the black bean soy sauce produced by the method of this invention combines the nutrition and color of black beans, with a protein content of 10.0g / 100ml and a sugar content of 7.6g / 100ml, and a reddish and glossy color.

[0029] 4. The black bean soy sauce produced by the method of the present invention can reduce the salt and sodium content without changing the overall flavor of the soy sauce. The salt content (calculated as Cl-) is ≤13.5g / 100ml and the sodium content is reduced to 3800mg / 100ml. Both salt and sodium are reduced by more than 25% compared with normal soy sauce, achieving true salt and sodium reduction. Attached Figure Description

[0030] Figure 1 This is a graph showing the physicochemical properties of the black bean reduced-sodium soy sauce prepared in Example 1 of this invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the embodiments. The following embodiments are descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0032] The various experimental operations involved in the specific embodiments are all conventional techniques in the field. For parts not specifically annotated in this document, those skilled in the art can refer to various commonly used reference books, scientific and technological documents or related instructions and manuals prior to the filing date of this invention to carry out the operations.

[0033] A method for preparing additive-free, low-sodium black bean soy sauce, the method comprising the following steps:

[0034] (1) Soaking: Soak black beans in drinking water until there is no white core, stir well, and you will get soaked black beans;

[0035] (2) Steaming: Place the soaked black beans from step (1) into a steaming pot, and after venting and draining the air, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no white heart is left, to obtain cooked black beans. Then add roasted wheat and mix it evenly with the cooked black beans. Simmer for 15 minutes to obtain koji.

[0036] (3) Making koji: Cool the koji material that has been simmered in step (2) back to 30-35℃, and then transport it to the koji making equipment to mix with koji extract. The amount of koji extract inoculated is 0.03% to 0.05%. After 40-44 hours of koji making, green or light green koji is produced.

[0037] (4) Making fermented wheat: Steam roasted wheat, inoculate with root enzymes and yeast, ferment at 28°C for 15 days to obtain fermented wheat with an alcohol content ≥12%, and set aside for later use.

[0038] (5) Fermentation: The koji obtained in step (3) and the 16% salt water are placed in a fermentation tank and mixed to obtain the initial soy sauce mash. The initial fermentation temperature is 45-50℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process takes 10-20 days. Add the fermented milk obtained in step (4) at a volume ratio of 100:1 to the initial soy sauce mash and the fermented milk, mix it evenly with the mash, stop the heat preservation, lower the fermentation temperature to 30-35℃, and add S yeast liquid to make the final yeast concentration of the mash ≥10. 4 CFU / ml, continue fermentation for 25-45 days, stirring or aerating daily during this period; each stirring lasts 30 seconds, allowing salt-tolerant yeast to multiply and produce aroma; the entire process takes 45-60 days to obtain flavor-enhancing sauce mash;

[0039] (6) Pressing or leaching: After fermentation is completed, press or leach the flavor-enhancing sauce mash obtained in step (5) and collect the crude oil;

[0040] (7) Sterilization treatment: The crude oil collected in step (6) is sterilized at a high temperature of 121-125℃ to obtain low-sodium black bean soy sauce.

[0041] Preferably, the mass ratio of black beans to roasted wheat is 700:250.

[0042] Preferably, in step (5), the volume of brine added is 1.4 to 1.6 times the mass of the fermented product.

[0043] Preferably, the S yeast liquid in (5) is salt-tolerant Rhus oryzae, and the amount added is such that the final yeast concentration of the fermented mash is ≥10. 4 cfu / ml.

[0044] Preferably, in step (4), the root enzyme is brewing root enzyme and the yeast is brewing yeast. First, brewing root enzyme is added to the steamed roasted wheat and fermented for 10 days. Then, brewing yeast is added and fermented for 5-10 days until the alcohol content is ≥12℃.

[0045] Preferably, the mass ratio of roasted wheat: brewing root enzyme: brewing yeast is 10:0.05:0.03.

[0046] Preferably, the reduced-sodium black bean soy sauce obtained in step (7) has amino acid nitrogen ≥ 0.8 g / 100 ml, total nitrogen ≥ 1.5 g / 100 ml, total acid ≤ 2.5 g / 100 ml, protein content of 10 g / 100 ml, sugar content of 7.6 g / 100 ml, salt content (calculated as Cl-) ≤ 13.5 g / 100 ml, sodium content reduced to 3800 mg / 100 ml, and total bacterial count ≤ 1000 cfu / ml.

[0047] Specifically, the relevant preparation and testing methods are as follows:

[0048] A method for preparing additive-free, low-sodium black bean soy sauce, the method comprising the following steps:

[0049] (1) Raw material preparation: Black beans and roasted wheat are added to the silo in a mass ratio of 700:300 to prepare for discharge.

[0050] (2) Soaking: Soak 700 kg of black beans in 1200 kg of water for 10 hours until there is no white core. Stir twice during the process to ensure that the black beans are soaked evenly.

[0051] (3) Steaming: Put the soaked black beans into the steaming tank, and after venting and draining, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no white heart is obtained, and then mix 250 kg of roasted wheat with the black bean cooked material and simmer for 15 minutes to make the roasted wheat and black bean cooked material evenly mixed and sterilized by heat, and obtain the starter material.

[0052] (4) Making koji: Cool the simmered koji material back to 33°C, then transport it to the koji-making equipment and mix it with koji extract. The amount of koji extract inoculated is 400g. After 42.5 hours of koji-making, green or light green koji is produced.

[0053] (5) Making wine cheese: Add 30kg of water to 50kg of roasted wheat, steam it in a rice steamer, put it into a large barrel, add 25g of brewing root enzyme powder, ferment at 28℃ for 10 days until the material bubbles and produces wine, add 20ml of brewing yeast, continue fermenting for 5 days to obtain wine cheese with an alcohol content ≥12%, and set aside for later use.

[0054] (6) Fermentation: Mix the koji and 1.5 times the volume of 16% salt brine (volume: weight of raw materials, i.e., the volume of 16% salt brine added is 1.5 times the mass of the koji) in a fermentation tank to obtain the initial soy sauce mash. The initial fermentation temperature is 45-48℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process lasts for 15 days. Add the fermented rice wine obtained in step (5) at a volume ratio of 100:1 to the initial soy sauce mash and add the rice wine. Mix it evenly with the mash. Stop the heat preservation and lower the fermentation temperature to 30-35℃. Add 25L of S yeast liquid and continue fermentation for 45 days. During this period, stir or aerate daily for 30 seconds each time. The entire process takes 60 days to obtain the flavored soy sauce mash.

[0055] (7) Pressing: After fermentation is complete, press the flavor-enhancing mash to collect the crude oil.

[0056] (8) Sterilization treatment: The crude oil is sterilized briefly at 121-125℃, and the total bacterial count is determined to be ≤1000 cfu / ml, thus obtaining black bean reduced-sodium soy sauce. Relevant test results are shown in Tables 1 and 2. Figure 1 .

[0057] Table 1. Detection of Fermentation Cycle Indicators for Black Bean Reduced Salt Soy Sauce

[0058] Fermentation days amino acid nitrogen g / 100ml Salt g / 100mL Total acid g / 100ml Fermentation temperature ℃ 0 0.00 12.02 0.00 48 3 0.90 11.80 1.59 48 6 0.99 12.82 1.74 45 9 0.97 12.64 1.82 45 12 0.95 12.14 1.89 45 15 0.99 12.94 1.98 45 22 1.03 12.58 2.13 35 29 1.01 12.11 2.16 32 36 1.00 12.99 2.19 33 45 1.02 12.87 2.23 33 54 1.01 13.23 2.25 32 60 1.02 12.85 2.32 32

[0059] As the test results above show, under this process, premium brewed soy sauce that fully meets national food safety standards can be fermented in 60 days, shortening the fermentation cycle of normal black bean soy sauce and achieving the effect of reducing salt and sodium.

[0060] Table 2 shows the physicochemical properties of the black bean reduced-sodium soy sauce:

[0061]

[0062] Experiments showed that reduced-salt black bean soy sauce, due to its lower brine concentration and smaller amount of brine added, had a lower raw material utilization rate, but its amino acid nitrogen and total nitrogen content were higher than those of normal-salt black bean soy sauce. The experiment also revealed a 29.47% reduction in salt content.

[0063] Example 2:

[0064] A method for preparing additive-free, low-sodium black bean soy sauce, the method comprising the following steps:

[0065] (1) Raw material preparation: Black beans and roasted wheat are added to the silo in a ratio of 700:300 to prepare for discharge.

[0066] (2) Soaking: Soak 700 kg of black beans in 1200 kg of water for 10 hours until there is no white core. Stir twice during the process to ensure that the black beans are soaked evenly.

[0067] (3) Steaming: Put the soaked black beans into the steaming tank, and after venting and draining, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no white heart is obtained, and then mix 250 kg of roasted wheat with the black bean cooked material and simmer for 15 minutes to make the roasted wheat and black bean cooked material evenly mixed and sterilized by heat, and obtain the starter material.

[0068] (4) Making koji: Cool the simmered koji material back to 33°C, then transport it to the koji-making equipment and mix it with koji extract. The amount of koji extract inoculated is 400g. After 44 hours of koji-making, green or light green koji is produced.

[0069] (5) Making wine cheese: Add 30kg of water to 50kg of roasted wheat, steam it in a rice steamer, put it into a large barrel, add 25g of brewing root enzyme powder, ferment at 28℃ for 10 days until the material bubbles and produces wine, add 20ml of brewing yeast, continue fermenting for 5 days to obtain wine cheese with an alcohol content ≥12%, and set aside for later use.

[0070] (6) Fermentation: Mix the koji and 1.5 parts (volume: weight of raw materials, i.e., the volume of 16% salt brine added is 1.5 times the mass of the koji) in a fermentation tank to obtain the initial soy sauce mash. The initial fermentation temperature is 48-50℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process lasts for 20 days. Add the fermented rice wine obtained in step (5) at a volume ratio of 100:1 to the initial soy sauce mash and add the rice wine. Mix it evenly with the mash. Stop the heat preservation and lower the fermentation temperature to 30-35℃. Add 25L of S yeast liquid and continue fermentation for 30 days. During this period, stir or aerate daily for 30 seconds each time. The entire process takes 50 days to obtain the flavorful soy sauce mash.

[0071] (7) Pressing: After fermentation is complete, press the flavor-enhancing mash to collect the crude oil.

[0072] (8) Sterilization treatment: The crude oil is sterilized at a high temperature of 121-125℃ for a short time. The total number of colonies is measured to be ≤1000cfu / ml, which yields black bean reduced salt soy sauce. The relevant test results are shown in Tables 3 and 4.

[0073] Table 3. Detection of Fermentation Cycle Indicators for Black Bean Reduced Salt Soy Sauce

[0074]

[0075] As the test results above show, under this process, premium brewed soy sauce that fully meets national food safety standards can be fermented in 50 days, shortening the fermentation cycle of normal black bean soy sauce and achieving the effects of reducing salt and sodium. Compared with Example 1, its fermentation process is negatively correlated with the initial fermentation temperature, and due to the shorter fermentation cycle, the total acid content is lower than that of Example 1.

[0076] Table 4 shows the physicochemical properties of the black bean reduced-sodium soy sauce:

[0077]

[0078] Experiments showed that reduced-salt black bean soy sauce, due to its lower brine concentration and smaller amount of brine added, had a lower raw material utilization rate, but its amino acid nitrogen and total nitrogen content were higher than those of normal-salt black bean soy sauce. The experiment also revealed a 29.97% reduction in salt content.

[0079] Example 3:

[0080] A method for preparing additive-free, low-sodium black bean soy sauce, the method comprising the following steps:

[0081] (1) Raw material preparation: Black beans and roasted wheat are added to the silo in a ratio of 700:300 to prepare for discharge.

[0082] (2) Soaking: Soak 700 kg of black beans in 1200 kg of water for 10 hours until there is no white core. Stir twice during the process to ensure that the black beans are soaked evenly.

[0083] (3) Steaming: Put the soaked black beans into the steaming tank, and after venting and draining, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no white heart is obtained, and then mix 250 kg of roasted wheat with the black bean cooked material and simmer for 15 minutes to make the roasted wheat and black bean cooked material evenly mixed and sterilized by heat, and obtain the starter material.

[0084] (4) Making koji: Cool the koji material to 35°C and transport it to the koji making equipment. Mix it with koji extract. The amount of koji extract inoculated is 400g. After 40 hours of koji making, green or light green koji is produced.

[0085] (5) Making wine cheese: Add 30kg of water to 50kg of roasted wheat, steam it in a rice steamer, put it into a large barrel, add 25g of brewing root enzyme powder, ferment at 28℃ for 10 days until the material bubbles and produces wine, add 20ml of brewing yeast, continue fermenting for 5 days to obtain wine cheese with an alcohol content ≥12%, and set aside for later use.

[0086] (6) Fermentation: Mix the koji and 1.5 times the volume of 16% salt brine (volume: weight of raw materials, i.e., the volume of 16% salt brine added is 1.5 times the mass of the koji) in a fermentation tank to obtain the initial soy sauce mash. The initial fermentation temperature is 45-48℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process lasts for 20 days. Add the fermented rice wine obtained in step (5) at a volume ratio of 100:1 to the initial soy sauce mash and add the rice wine. Mix the mash evenly and stop the heat preservation. Lower the fermentation temperature to 30-35℃ and add 25L of S yeast liquid. Continue fermentation for 25 days. During this period, stir or aerate daily for 30 seconds each time. The entire process takes 45 days to obtain the flavor-enhanced soy sauce mash.

[0087] (7) Pressing: After fermentation is complete, press the flavor-enhancing mash to collect the crude oil.

[0088] (8) Sterilization treatment: The crude oil is sterilized at a high temperature of 121-125℃ for a short time. The total number of colonies is ≤1000cfu / ml, which is the result of black bean reduced salt soy sauce. The relevant test results are shown in Tables 5 and 6.

[0089] Table 5. Detection of Fermentation Cycle Indicators for Black Bean Reduced Salt Soy Sauce

[0090]

[0091] As can be seen from the above test results, under this process, a premium brewed soy sauce that fully meets the national food safety standards can be fermented in 45 days. However, compared with Examples 1 and 2, the total acid content is lower than that of Examples 1 and 2, and the overall flavor is thinner than that of Examples 1 and 2.

[0092] Table 6 shows the physicochemical properties of the black bean reduced-sodium soy sauce:

[0093]

[0094] According to the experiment, Example 3 had a short fermentation cycle, resulting in low raw material utilization, but its amino acid nitrogen and total nitrogen were higher than those of black bean soy sauce with normal salt content. The experiment showed that the salt content was reduced by 30.57%.

[0095] Meanwhile, by comparing Examples 1-3, it can be seen that the koji-making time in the koji-making step, the initial fermentation temperature of 48-50℃ in the early stage of the fermentation step, and the overall process time in the method of the present invention have a synergistic effect, which can synergistically improve the salt and sodium content of the soy sauce prepared by the method of the present invention.

[0096] The key technical points of this invention are as follows:

[0097] (1) Raw materials: Black beans and roasted wheat are used as raw materials. Through the innovation of fermentation process, the salt and sodium of soy sauce are reduced without any additives.

[0098] (2) Steaming: Steam the black beans until cooked, mix them with roasted wheat, and simmer until cooked.

[0099] (3) Making koji: After the simmered koji material has cooled down, it is mixed with koji essence. The amount of koji essence inoculated is 0.03% to 0.05%. It is then transported to the koji making equipment and made into green or light green koji after 40 to 44 hours.

[0100] (4) Making wine cheese: Steam roasted wheat, inoculate with root enzymes and brewer's yeast, ferment at 28°C for 15 days to obtain wine cheese with an alcohol content ≥12%, and set aside for later use.

[0101] (5) Fermentation: During the fermentation process, the concentration of brine is reduced to obtain preliminary soy sauce mash. The initial fermentation temperature is 45-50℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process takes 10-20 days. To prevent spoilage and contamination by miscellaneous bacteria after the temperature drops, the yeast from (4) is added while the temperature is lowered to ensure that the mash contains a certain amount of alcohol, thus preventing spoilage and contamination by miscellaneous bacteria. The fermentation temperature is lowered to 30-35℃, and Rhus oryzae liquid is introduced. Fermentation continues for 25-45 days, during which time stirring or aeration is performed daily for 30 seconds each time. This allows the salt-tolerant yeast to multiply and produce aroma. The entire process takes 45-60 days to obtain aroma-enhanced soy sauce mash.

[0102] (6) Pressing or leaching: After fermentation is complete, press or leach the flavor-enhancing mash and collect the crude oil.

[0103] (7) Sterilization treatment: The crude oil is sterilized at a high temperature of 121-125℃ and the total number of colonies is measured to be ≤1000cfu / ml, which yields black bean reduced salt soy sauce.

[0104] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing a low-sodium black bean soy sauce without additives, characterized in that: The method includes the following steps: (1) Soaking: Soak black beans in drinking water until there is no white core, stir well, and you will get soaked black beans; (2) Steaming: Place the soaked black beans from step (1) into a steaming tank. After venting and draining the water, steam at 0.15 MPa for 5-8 minutes until the black bean hearts change color and no longer have white hearts. Then add roasted wheat and mix it evenly with the black bean cooked material. Simmer for 15 minutes to obtain the starter. (3) Making koji: Cool the koji material that has been simmered in step (2) back to 30-35℃, and transport it to the koji making equipment to mix with koji essence. The amount of koji essence inoculated is 0.03% to 0.05%. After 40-44 hours of koji making, green or light green koji is produced. (4) Making wine cheese: Steam roasted wheat, inoculate with root enzymes and yeast, ferment at 28°C for 15 days to obtain wine cheese with an alcohol content ≥12%, and set aside for later use. (5) Fermentation: The koji obtained in step (3) and the brine with 16% salt content are placed in a fermentation tank and mixed to obtain the initial soy sauce mash. The initial fermentation temperature is 45-50℃. Stir or aerate twice a day for 30 seconds each time to make the mash uniform and inhibit the excessive reproduction of anaerobic microorganisms. This fermentation process takes 10-20 days. Add the fermented rice wine obtained in step (4) at a volume ratio of 100:1 to the initial soy sauce mash and the fermented rice wine. Mix it evenly with the mash. Stop the heat preservation and lower the fermentation temperature to 30-35℃. Add S yeast liquid to make the final yeast concentration of the mash ≥10. 4 CFU / ml, continue fermentation for 25-45 days, stirring or aerating daily during this period; each stirring lasts 30 seconds, allowing salt-tolerant yeast to multiply and produce aroma; the entire process takes 45-60 days to obtain flavor-enhancing sauce mash; (6) Pressing or leaching: After fermentation is completed, press or leach the flavor-enhancing mash obtained in step (5) to collect the crude oil; (7) Sterilization treatment: The crude oil collected in step (6) is sterilized at a high temperature of 121-125℃ to obtain low-sodium black bean soy sauce; In step (5), the volume of brine added is 1.4 to 1.6 times the mass of the finished product. In (5), the S yeast liquid is salt-tolerant Rhus oryzae, and the amount added is such that the final yeast concentration of the fermented mash is ≥10. 4 cfu / ml.

2. The preparation method according to claim 1, characterized in that: The mass ratio of black beans to roasted wheat is 700:

250.

3. The preparation method according to claim 1, characterized in that: In step (4), the root enzyme is brewing root enzyme and the yeast is brewing yeast. First, add brewing root enzyme to the steamed roasted wheat and ferment for 10 days. Then add brewing yeast and ferment for 5-10 days until the alcohol content is ≥12℃.

4. The preparation method according to claim 3, characterized in that: The mass ratio of roasted wheat, brewing root enzyme, and brewing yeast is 10:0.05:0.03.

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