A method for cleaning soy sauce pressing filter cloth

Abstract

The present invention relates to the technical field of filter cloth cleaning, and more specifically, to a method for cleaning soy sauce press filter cloth. The method comprises: removing the soy sauce press filter cloth from the residue, soaking it in a composite enzyme solution for a first cleaning step; subsequently soaking it in hot water for a second cleaning step; and then spraying the filter cloth with electrolyzed water for disinfection and storage. This method replaces existing cleaning methods by combining composite enzyme solution and high-temperature water cleaning. The multiple enzyme systems in the composite enzyme solution hydrolyze grease and residue on the filter cloth, and high-temperature water washing increases the dissolution and sterilization of the hydrolyzed products. While maintaining the filtering performance of the cleaned filter cloth, it also reduces one water washing step, saving approximately 30% of cleaning water and simultaneously reducing wastewater discharge by approximately 30%.

Description

Technical Field

[0001] The invention relates to the technical field of filter cloth cleaning, and in particular to a method for cleaning a soy sauce pressing filter cloth. Background Art

[0002] Cantonese-style high-salt, dilute soy sauce is primarily brewed from soybeans and wheat. After fermentation, the oil is poured and squeezed out to produce raw soy sauce and soy sauce residue. However, during the oil extraction process using vertical hydraulic presses, the soybean oil, fiber, and protein in the residue adhere to the filter cloth due to pressure, clogging the filter pores and reducing processing capacity.

[0003] To address this issue, the industry generally uses a 5% caustic soda solution to clean the filter cloth after pressing. This saponifies the oil, softens the remaining soy sauce residue, and sterilizes it, removing grease and stains and reducing microbial activity. Nylon filter cloth, known for its alkali resistance, is widely used in soy sauce pressing. However, because existing cleaning methods include an alkali wash, two subsequent rinses with clean water are required, increasing the amount of water and wastewater used for cleaning, placing significant pressure on environmental protection.

[0004] Although nylon filter cloth performs well in alkali resistance, its heat resistance is not good enough and its resistance to oxidants is poor. This makes it impossible to disinfect the filter cloth by high temperature, electrolyzed water (oxidant), etc., and there is a problem that it cannot be stored for a long time. In comparison, polyester filter cloth, which is also a polyfiber material, has slightly weaker alkali resistance, but has excellent performance in high temperature resistance and oxidant resistance. The price is about 1 / 2 of nylon filter cloth, making it a good alternative. Summary of the Invention

[0005] Existing processes use nylon press filter cloth and a "caustic soda wash + water wash + water wash" method to clean and sterilize the press filter cloth. This method results in high water consumption and significant wastewater discharge, which are environmentally friendly issues. Furthermore, due to the nylon filter cloth's poor resistance to oxidants, it cannot be disinfected with disinfectants such as electrolyzed water after cleaning. The present invention aims to provide a method for cleaning and disinfecting polyester press filter cloth used in Cantonese soy sauce pressing. By replacing the polyester press filter cloth with an "enzyme solution wash + hot water wash" method, the present invention improves the existing problems of high water consumption, significant wastewater discharge, and high filter cloth cost (pressing operating costs) associated with alkali washing of the filter cloth, while ensuring effective cleaning and sterilization. Furthermore, the press filter cloth can be disinfected with electrolyzed water, extending its shelf life.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for cleaning a soy sauce pressing filter cloth comprises the following steps:

[0008] (1) Koji making: adding bacterial strains to the koji making raw materials and culturing them to obtain finished koji; the bacterial strains are a mixed species of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5;

[0009] (2) preparing a complex enzyme solution: adding low-salt warm water to the finished koji obtained in step (1), adjusting the pH value, extracting, and filtering to obtain a complex enzyme solution;

[0010] (3) First cleaning: remove the residue from the soy sauce pressing filter cloth and then soak and wash it with a complex enzyme solution;

[0011] (4) Second cleaning: The filter cloth after the first cleaning is soaked and washed with hot water;

[0012] (5) Disinfection and storage: Spray the filter cloth with electrolyzed water for disinfection and storage.

[0013] Preferably, in step (1), the koji-making raw material is a mixture of desalted soy sauce residue, wheat flour, cooked soybean meal and water; wherein the mass ratio of desalted soy sauce residue, wheat flour and cooked soybean meal is 6:1.5:2.5; water is added to adjust the moisture content to 45% to 50%; the incubation temperature is 28 to 34° C., and the incubation time is 48 to 72 hours.

[0014] Preferably, in step (2), the mass ratio of the koji to the low-salt warm water is 1:(2.5-3.5); wherein the salt content of the low-salt warm water is 0.5-2.0 g / 100 mL, and the temperature is 35-40° C.; the pH value is 7.5±0.5; and the extraction time is 40 min.

[0015] Preferably, in step (3), the soaking and washing is carried out at a temperature of 35 to 40° C. and for a time of 45 to 75 minutes.

[0016] Preferably, in step (4), the temperature of the hot water is 80-90° C.; and the soaking and washing time is 45-60 minutes.

[0017] Preferably, in step (5), the concentration of the electrolyzed water is 50 to 100 ppm.

[0018] Preferably, the soy sauce pressing filter cloth is made of polyester.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. Combining compound enzyme liquid and high-temperature water cleaning to replace the existing cleaning method, the multiple enzyme systems (protease system, lipase system, etc.) in the compound enzyme liquid can enzymatically hydrolyze the grease and residue on the filter cloth, and high-temperature water washing increases the dissolution of the enzymatic hydrolyzate and the sterilization effect. While ensuring the filtering performance of the filter cloth after cleaning, it reduces one water washing operation, saves about 30% of the cleaning water, and at the same time reduces the discharge of wastewater by about 30%.

[0021] 2. By optimizing and improving the cleaning method, the nylon filter cloth suitable for alkali washing is replaced with a lower-priced polyester filter cloth. The operating cost of the filter cloth can be reduced by about 45%. At the same time, the replacement of the filter cloth solves the problems of disinfection and storage of the filter cloth, extending the storage time.

[0022] 3. The present invention adopts a sauce residue culture medium and a mixed fermentation method of multiple strains, and utilizes the oil in the sauce residue culture medium to encourage different strains to produce more types of lipase systems, and the lipase activity of the finished koji reaches more than 1100U / g; at the same time, neutral and acidic protease systems are produced through the growth metabolism of Aspergillus oryzae and Aspergillus niger, enriching the types of enzyme systems in the system and enhancing the ability of the enzyme solution to enzymatically hydrolyze filter cloth oil and residue. DETAILED DESCRIPTION

[0023] Embodiment 1:

[0024] Using polyester press filter cloth:

[0025] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0026] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0027] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0028] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0029] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0030] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0031] Example 2:

[0032] Using polyester press filter cloth:

[0033] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 60 minutes at a temperature of 36°C.

[0034] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 86℃ hot water for 50 minutes, and then dehydrated and dried.

[0035] ③Disinfection and storage: Use 70ppm electrolyzed water to spray the filter cloth for disinfection and storage.

[0036] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0037] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 50%, inoculate the bacterial strain, mix well, crush, and culture at 30°C for 60 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0038] ② Preparation of complex enzyme solution: Add 3.2 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 1.8g / 100mL and the temperature is 40℃.

[0039] Example 3:

[0040] Using polyester press filter cloth:

[0041] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 70 minutes at a temperature of 35°C.

[0042] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed with 83℃ hot water for 60 minutes, and then dehydrated and dried.

[0043] ③Disinfection and storage: Use 90ppm electrolyzed water to spray the filter cloth for disinfection and storage.

[0044] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0045] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 28°C for 72 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0046] ② Preparation of complex enzyme solution: Add 3.5 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 1.0g / 100mL and the temperature is 35°C.

[0047] Comparative Example 1:

[0048] Using nylon press filter cloth:

[0049] ① First cleaning: After deslagging, the filter is placed in a drum washing machine and soaked and washed with 5% caustic soda solution for 50 minutes.

[0050] ② Second cleaning: Soak the filter cloth after the first cleaning in clean water for 45 minutes.

[0051] ②The third cleaning: Soak the filter cloth after the second cleaning in clean water for 45 minutes, and then dehydrate and dry it.

[0052] Comparative Example 2:

[0053] Using nylon press filter cloth:

[0054] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0055] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0056] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0057] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0058] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0059] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0060] Comparative Example 3:

[0061] Using polyester press filter cloth:

[0062] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked in clean water for 45 minutes at a temperature of 40°C.

[0063] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0064] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0065] Comparative Example 4:

[0066] Using polyester press filter cloth:

[0067] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0068] ② Second cleaning: Soak the filter cloth after the first cleaning in clean water for 45 minutes, and then dehydrate and dry it.

[0069] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0070] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0071] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0072] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0073] Comparative Example 5:

[0074] Using polyester press filter cloth:

[0075] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked in hot water for 45 minutes at a temperature of 88°C.

[0076] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40°C, and then dehydrated and dried.

[0077] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0078] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0079] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5.

[0080] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0081] Comparative Example 6:

[0082] Using polyester press filter cloth:

[0083] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0084] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0085] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0086] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0087] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is Aspergillus oryzae.

[0088] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0089] Comparative Example 7:

[0090] Using polyester press filter cloth:

[0091] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0092] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0093] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0094] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0095] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is Aspergillus niger.

[0096] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0097] Comparative Example 8:

[0098] Using polyester press filter cloth:

[0099] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0100] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0101] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0102] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0103] ① Koji making: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain koji; the bacterial strain is Rhizopus.

[0104] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0105] Comparative Example 9:

[0106] Using polyester press filter cloth:

[0107] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0108] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0109] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0110] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0111] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain the koji; the bacterial strain is a mixture of Aspergillus niger and Rhizopus, with a mass ratio of 2:5.

[0112] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0113] Comparative Example 10:

[0114] Using polyester press filter cloth:

[0115] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0116] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0117] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0118] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0119] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain the koji; the bacterial strains are a mixture of Aspergillus oryzae and Rhizopus, with a mass ratio of 3:5.

[0120] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0121] Comparative Example 11:

[0122] Using polyester press filter cloth:

[0123] ① First cleaning: After removing the residue, the filter is placed in a drum washing machine and soaked and washed with complex enzyme solution for 45 minutes at a temperature of 40℃.

[0124] ② Second cleaning: After the first cleaning, the filter cloth is soaked and washed in 88℃ hot water for 45 minutes, and then dehydrated and dried.

[0125] ③Disinfection and storage: Spray the filter cloth with 50ppm electrolyzed water for disinfection and storage.

[0126] The complex enzyme solution used in the first cleaning step is prepared by the following method:

[0127] ① Koji preparation: Take 6 parts by mass of desalted soy sauce residue, 1.5 parts by mass of wheat flour, and 2.5 parts by mass of cooked soybean meal, add water to adjust the moisture content to 46%, inoculate the bacterial strain, mix well, crush, and culture at 33°C for 50 hours to obtain the koji; the bacterial strains are a mixture of Aspergillus oryzae and Aspergillus niger, with a mass ratio of 3:2.

[0128] ② Preparation of complex enzyme solution: Add 2.7 times the weight of low-salt warm water to the finished koji, adjust the pH to 7.5, extract for 40 minutes, and then filter to obtain the complex enzyme solution, wherein the salt content of the low-salt warm water is 0.7g / 100mL and the temperature is 38°C.

[0129] Effect detection:

[0130] Comparing Examples 1 to 3 with Comparative Examples 1 to 11, the obtained sauce mash processing capacity, washing water consumption, wastewater discharge, oil filtration capacity of the filter cloth in 1 hour, total number of colonies on the filter cloth after washing, storage days, total number of colonies on the filter cloth after storage, koji lipase activity, and filter cloth cost can be seen in Table 1 below.

[0131] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0132]

[0133]

Claims

1. A method for cleaning a soy sauce pressing filter cloth, characterized in that: The steps include: (1) Koji making: adding bacterial strains to the koji making raw materials and culturing them to obtain finished koji; the bacterial strains are a mixture of Aspergillus oryzae, Aspergillus niger, and Rhizopus, with a mass ratio of 3:2:5; (2) Preparing a complex enzyme solution: adding low-salt warm water to the finished koji obtained in step (1), adjusting the pH value, and then extracting and filtering to obtain a complex enzyme solution; (3) First cleaning: remove the residue from the soy sauce pressing filter cloth and then soak and wash it with a compound enzyme solution; (4) Second cleaning: The filter cloth after the first cleaning is soaked and washed with hot water; (5) Disinfection and storage: Spray the filter cloth with electrolyzed water for disinfection and storage.

2. The method according to claim 1, characterized in that In step (1), the koji-making raw material is a mixture of desalted soy sauce residue, wheat flour, cooked soybean meal and water; wherein the mass ratio of desalted soy sauce residue, wheat flour and cooked soybean meal is 6:1.5:2.5; water is added to adjust the moisture content to 45% to 50%; the incubation temperature is 28 to 34°C, and the incubation time is 48 to 72 hours.

3. The method according to claim 1, characterized in that In step (2), the mass ratio of the koji to the low-salt warm water is 1:(2.5-3.5); wherein the salt content of the low-salt warm water is 0.5-2.0 g / 100 mL, and the temperature is 35-40° C.; the pH value is 7.5±0.5; and the extraction time is 40 min.

4. The method according to claim 1, wherein In step (3), the soaking and washing is performed at a temperature of 35-40° C. and for a time of 45-75 minutes.

5. The method according to claim 1, wherein In step (4), the temperature of the hot water is 80-90° C.; the soaking and washing time is 45-60 minutes.

6. The method according to claim 1, wherein In step (5), the concentration of the electrolyzed water is 50-100 ppm.

7. The method according to claim 1, characterized in that The material of the soy sauce pressing filter cloth is polyester.

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