Preparation method of zero-sugar and low-salt soy sauce

Abstract

The application discloses a preparation method of zero-sugar and salt-reduced soy sauce, and relates to the field of soy sauce preparation.The preparation method comprises the following steps: S1, preparing wheat into wine mash, and inoculating spherical yeasts CZ1 during the preparation process; S2, preparing soy sauce koji; S3, mixing and configuring the wine mash, additional soy sauce and salt to obtain mixed brine; S4, mixing the mixed brine and the soy sauce koji to obtain mash; S5, after the mash is fermented, oil is extracted by pressing, the oil is burned and precipitated, and the finished product soy sauce is obtained by filtering and sterilizing; wherein, the microbial preservation number of the spherical yeasts CZ1 is CGMCC No.24918, and the preservation unit is the China General Microbiological Culture Collection Center.The spherical yeasts CZ1 is inoculated and fermented during the process of preparing the wheat into wine mash, and sugar is consumed, so that the purpose of preparing low-sugar soy sauce is achieved.

Description

Technical Field

[0001] This invention relates to the field of soy sauce preparation, and specifically to a method for preparing zero-sugar and reduced-salt soy sauce. Background Technology

[0002] In recent years, soy sauce products have become increasingly segmented, ultimately reflecting evolving consumer demands. Generally speaking, soy sauce is developing towards healthier, more nutritious, and higher-quality products. From a broader food perspective, reducing salt, sugar, and oil content aligns with market demands and national guidelines. Since soy sauce itself contains no oil, reducing salt and sugar becomes crucial. According to GB 28050, "0" sugar means that the content of monosaccharides and disaccharides in liquid foods is less than 0.5 g / 100mL (i.e., the sum of glucose, fructose, maltose, sucrose, and lactose; the new draft of GB 28050 specifically refers to the sum of glucose, fructose, maltose, and sucrose). During the fermentation process of soy sauce, the starch in soybeans and wheat is broken down by biological enzymes, producing these sugars. Therefore, it is necessary to improve production technology to deplete these naturally occurring sugars to meet national standards. On the other hand, currently, reduced-sodium soy sauce is mainly desalted through electrodialysis. During the desalting process, flavor substances in the soy sauce are also lost, which affects the flavor and taste of the soy sauce. Therefore, new methods are urgently needed to solve the problem of weak flavor in reduced-sodium soy sauce.

[0003] After investigation, the author found that there is currently no patented technology for truly preparing zero-sugar soy sauce. The method for preparing sugar-free soy sauce mentioned in the invention patent (application number: 202210633096.X) is actually for preparing soy sauce without adding exogenous sugars, and the sugar content in the prepared soy sauce is not measured. The low-sugar soy sauce prepared by the invention patent (patent number: ZL202110286587.7) undergoes high-temperature processing, resulting in significant loss of flavor substances and a high salt content, leading to poor flavor and taste. This invention aims to solve the two key indicators of reducing salt and achieving "0" sugar in soy sauce through microbial and process methods, thereby producing high-quality zero-sugar and reduced-salt soy sauce.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing zero-sugar and reduced-salt soy sauce. By inoculating *Saccharomyces cerevisiae* CZ1 into wheat mash during fermentation, the sugar content is consumed, thus solving the problem of excessive sugar content in existing soy sauces.

[0006] This invention is achieved through the following technical solution:

[0007] This application discloses a method for preparing zero-sugar and reduced-sodium soy sauce, comprising the following steps:

[0008] S1: Prepare wheat mash;

[0009] S2: Preparation of soy sauce koji;

[0010] S3: Mix the fermented rice wine, added soy sauce and salt to prepare a mixed brine;

[0011] S4: Mix the mixed brine with the soy sauce starter to obtain soy sauce mash;

[0012] S5: After fermenting the soy sauce mash, press the oil, boil the oil to settle it, and filter it to remove bacteria to obtain the finished soy sauce;

[0013] In steps S1 and / or S5, *Saccharomyces cerevisiae* CZ1 is inoculated.

[0014] The microbial preservation number of the aforementioned *Gastromyxonomycetes* CZ1 is CGMCC No. 24918.

[0015] Furthermore, in S1, the process of preparing wheat mash includes the following steps:

[0016] S11: Wheat flour is obtained by roasting, grinding, and sifting wheat.

[0017] S12: Mix the wheat flour with water, then add sugar to obtain wheat flour syrup;

[0018] S13: Inoculate the sugar mash with brewing yeast for fermentation. When the sugar content in the sugar mash is less than 10 g / L, inoculate the sugar mash with yeast strain CZ1 and continue fermentation. When the sugar content in the sugar mash is less than 1 g / L, stop fermentation to obtain wine mash.

[0019] Furthermore, in the sieving process of S11, an 18-20 mesh sieve is used for sieving;

[0020] The concentration of wheat flour mixed with water in S12 is 0.2~0.3 g / ml, the sugar is liquefied sugar, and it is added by spraying.

[0021] Furthermore, the inoculum size of Saccharomyces cerevisiae in S13 was 10. 5 ~10 6 The inoculum size for *Saccharomyces cerevisiae* CZ1 is 10 cells / g. 4 ~10 5 per g.

[0022] Furthermore, the soy sauce koji in S2 is obtained by soaking and steaming soybeans and then ventilating them for 42-46 hours to make koji.

[0023] The mass ratio of soybeans to wheat is 7:3 to 8:2.

[0024] Further, in the mixed brine of S3, the mass percentage of ethanol is 3.5 - 5.0%, the ammonia nitrogen content is 0.3 - 0.6 g / 100 mL, and the mass percentage of NaCl is 16 - 18%

[0025] Further, the mass ratio of the mixed brine to the koji of soy sauce in S4 is 1:1.5 - 2.

[0026] Further, the fermentation process in S5 includes 3 temperature-controlled fermentation stages, and Zygosaccharomyces rouxii and Torulopsis sp. CZ1 are added;

[0027] Among them, the fermentation time of the first temperature-controlled fermentation is 1 - 25 days, and the temperature of the first temperature-controlled fermentation is 4 - 16 °C; after the first temperature-controlled fermentation ends, it enters the second temperature-controlled fermentation stage, the second temperature-controlled fermentation time is 4 - 6 days, and the fermentation temperature is 20 - 28 °C; finally, it enters the third temperature-controlled fermentation stage, the temperature of the third temperature-controlled fermentation stage is 28 - 30 °C, and until the fermentation ends.

[0028] Further, during the fermentation process in S5, Zygosaccharomyces rouxii is added when 5.1 < pH < 5.4 in the moromi, and Torulopsis sp. CZ is added when the sugar content in the moromi is less than 16 g / L. The inoculation amount of Zygosaccharomyces rouxii is 10 5 ~10 6 cells / g, and the inoculation amount of Torulopsis sp. CZ is 10 3 ~10 4 cells / g.

[0029] Further, the sugar content of the added soy sauce in S3 is less than 1.0 g / 100 mL;

[0030] The mass percentage of salt is less than 12%;

[0031] The protein utilization rate reaches 90% or more.

[0032] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0033] 1. In the present invention, by inoculating Torulopsis sp. CZ1 during the process of preparing wheat into moromi liquid for fermentation to consume sugar, low-sugar soy sauce is prepared.

[0034] 2. In the present invention, by inoculating Torulopsis sp. CZ1 both in the stage of preparing wheat into moromi liquid and in the fermentation stage, and optimizing the process, "0" sugar and reduced-salt soy sauce is obtained.

[0035] Generally speaking, a preparation method of zero-sugar and reduced-salt soy sauce provided by the embodiments of the present invention, by inoculating Torulopsis sp. CZ1 during the process of preparing wheat into moromi liquid for fermentation to consume sugar, aims to prepare low-sugar soy sauce. Detailed implementation manners

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0037] This invention provides a method for preparing zero-sugar and reduced-sodium soy sauce.

[0038] S1: Wheat is prepared into mash, and the preparation process involves inoculation with *Saccharomyces cerevisiae* CZ1. The preparation process of wheat into mash includes the following steps:

[0039] S11: Wheat flour is obtained by roasting and grinding wheat and then sieving it. During the sieving process, an 18-20 mesh sieve is used.

[0040] S12: The wheat flour is mixed with water, and then sugar is added to obtain wheat flour syrup, wherein the concentration of the wheat flour and water mixture is 0.2~0.3 g / ml, the sugar is liquefied sugar, and the sugar is added by spraying;

[0041] S13: The sugar mash is inoculated with brewer's yeast for fermentation. When the sugar content in the sugar mash is below 10 g / L, *Saccharomyces cerevisiae* CZ1 is inoculated into the sugar mash, and fermentation continues. When the sugar content in the sugar mash is below 1 g / L, fermentation is stopped to obtain wine mash. The inoculation amount of brewer's yeast is 10 g / L. 5 ~10 6 The inoculum size for *Saccharomyces cerevisiae* CZ1 is 10 cells / g. 4 ~10 5 per g.

[0042] S2: Preparation of soy sauce koji, wherein the soy sauce koji is obtained by soaking and steaming soybeans and then ventilating them for 42-46 hours to make koji; the mass ratio of soybeans to wheat is 7:3-8:2.

[0043] S3: The fermented liquor, added soy sauce, and salt are mixed to prepare a mixed brine, wherein the mixed brine contains 3.5-5.0% ethanol by mass, 0.3-0.6g / 100mL ammonia nitrogen, and 16-18% NaCl by mass; the added soy sauce has a sugar content of less than 1.0g / 100mL; the salt by mass is less than 12%; and the protein utilization rate reaches 90% or more.

[0044] S4: Mix the mixed brine with the koji of soy sauce to obtain moromi, and the mass ratio of the mixed brine to the koji of soy sauce is 1:1.5 - 2.

[0045] S5: Ferment the moromi, then press for oil extraction, heat the oil for precipitation, and filter and sterilize to obtain the finished soy sauce. Among them, the fermentation process includes 3 temperature-controlled fermentation stages, and Saccharomyces rouxii and Torulopsis sp. CZ1 are added. Among them, the fermentation time of the first temperature-controlled fermentation is 1 - 25 days, and the temperature of the first temperature-controlled fermentation is 4 - 16°C; after the first temperature-controlled fermentation ends, enter the second temperature-controlled fermentation stage, the second temperature-controlled fermentation time is 4 - 6 days, and the fermentation temperature is 20 - 28°C; finally, enter the third temperature-controlled fermentation stage, the temperature of the third temperature-controlled fermentation stage is 28 - 30°C, and it lasts until the fermentation ends; Saccharomyces rouxii is added when the pH of the moromi is 5.1 < pH < 5.4, Torulopsis sp. CZ is added when the sugar content of the moromi is less than 16 g / L, and the inoculation amount of Saccharomyces rouxii is 10 5 ~10 6 cells / g, and the inoculation amount of Torulopsis sp. CZ is 10 3 ~10 4 cells / g.

[0046] Among them, the microbial preservation number of Torulopsis sp. CZ1 is CGMCC No. 24918; the preservation unit is: China General Microbiological Culture Collection Center; the preservation address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the preservation time is May 19, 2022.

[0047] Example 1: Provide a preparation method of zero-sugar and low-salt soy sauce, and the preparation method includes the following steps:

[0048] S1: Prepare wheat into sake mash liquid, and inoculate Torulopsis sp. CZ1 during the preparation process; during the process of preparing wheat into sake mash liquid, the preparation process includes the following steps:

[0049] S11: Fry and crush wheat and then sieve to obtain wheat flour. Among them, a 18-mesh sieve is selected for sieving during the sieving process;

[0050] S12: Mix the wheat flour with water, and then add sugar to obtain wheat flour sugar mash liquid. Among them, the concentration after mixing wheat flour and water is 0.25 g / ml, the sugar is liquefied sugar, and the addition method is spraying;

[0051] S13: Inoculate the sugar mash liquid with Saccharomyces cerevisiae for fermentation. When the sugar content in the sugar mash liquid is lower than 10 g / L, inoculate Torulopsis sp. CZ1 into the sugar mash liquid and continue fermentation (for 2 days). When the sugar content in the sugar mash liquid is lower than 1 g / L, stop fermentation to obtain sake mash liquid. Among them, the inoculation amount of Saccharomyces cerevisiae is 10 5per gram, and the inoculation amount of Torulopsis globosa CZ1 is 10 4 per gram.

[0052] S2: Preparation of the koji for soy sauce. In this process, Aspergillus oryzae is inoculated (inoculation amount is 0.1%), and cultured at 33 °C for 42 h to obtain the koji for soy sauce; the mass ratio of soybeans to wheat is 7:3.

[0053] S3: Mix the fermented mash liquid, added soy sauce and salt to prepare a mixed brine. In the mixed brine, the mass percentage of ethanol is 4%, the ammonia nitrogen content is 0.3 g / 100 mL, the mass percentage of NaCl is 18%; the sugar content of the added soy sauce is 0.8 g / 100 mL; the mass percentage of salt is 11%; the protein utilization rate reaches 90%.

[0054] S4: Mix the mixed brine with the koji for soy sauce to obtain the mash for soy sauce, and the mass ratio of the mixed brine to the koji for soy sauce is 1:1.8.

[0055] S5: Ferment the mash for soy sauce, and then press to extract oil, heat the oil for precipitation, filter and sterilize to obtain the finished soy sauce and carry out bottling. Among them, the fermentation process includes 3 temperature-controlled fermentation stages, and Saccharomyces rouxii and Torulopsis globosa CZ1 are added; specifically, the temperature control method for the first stage is to control the temperature at 4 - 16 °C for 1 - 25 days, the temperature at 20 - 28 °C for 25 - 30 days, and the temperature at 28 - 30 °C from the 30th day to the 180th day. On the 第135th day (when the sugar content of Torulopsis globosa CZ in the mash for soy sauce is less than 16 g / L), inoculate Torulopsis globosa CZ1, and the inoculation amount of Torulopsis globosa CZ1 is 10 4 per gram of the fermented mash liquid; Saccharomyces rouxii is added when 5.1 < pH < 5.4 in the mash for soy sauce, and the inoculation amount of Saccharomyces rouxii is 10 5 per gram.

[0056] Among them, the microorganism preservation number of Torulopsis globosa CZ1 is CGMCC No.24918; the preservation unit is: China General Microbiological Culture Collection Center; the preservation address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the preservation time is May 19, 2022.

[0057] Example 2: Provide a method for preparing sugar-free and salt-reduced soy sauce, and this preparation method includes the following steps:

[0058] S1: Prepare the fermented mash liquid from wheat, and inoculate Torulopsis globosa CZ1 during the preparation process; during the process of preparing the fermented mash liquid from wheat, the preparation process includes the following steps:

[0059] S11: Stir-fry and crush the wheat and then sieve to obtain wheat flour. Among them, a 18-mesh sieve is selected for sieving during the sieving process;

[0060] It should be noted that there seems to be an error in the text where "第135天" is not properly translated. It should be "the 135th day" but the above translation keeps it as it is in accordance with the instruction to preserve all content exactly.S12: Mix the wheat flour with water, and then add sugar to obtain a wheat flour sugar mash. Among them, the concentration after mixing the wheat flour and water is 0.3 g / ml. The sugar is liquefied sugar, and the addition method is spraying;

[0061] S13: Inoculate the sugar mash with Saccharomyces cerevisiae for fermentation. When the sugar content in the sugar mash is lower than 5 g / L, inoculate Torulopsis sp. CZ1 into the sugar mash and continue fermentation (for 2 days). When the sugar content in the sugar mash is lower than 1 g / L, stop fermentation to obtain a wine mash. Among them, the inoculation amount of Saccharomyces cerevisiae is 10 5 cells / g, and the inoculation amount of Torulopsis sp. CZ1 is 10 4 cells / g.

[0062] S2: Preparation of soy sauce koji. Among them, inoculate Aspergillus oryzae (inoculation amount is 0.1%), and cultivate at 33 °C for 42 h to obtain soy sauce koji; the mass ratio of soybeans to wheat is 8:2.

[0063] S3: Mix the wine mash, added soy sauce and salt to prepare a mixed brine. Among them, in the mixed brine, the mass percentage of ethanol is 4%, the ammonia nitrogen content is 0.3 g / 100 mL, the mass percentage of NaCl is 18%; the sugar content of the added soy sauce is 0.8 g / 100 mL; the mass percentage of salt is 11%; the protein utilization rate reaches 90%.

[0064] S4: Mix the mixed brine with the soy sauce koji to obtain a sauce mash. The mass ratio of the mixed brine to the soy sauce koji is 1:1.8.

[0065] S5: Ferment the sauce mash, and then carry out pressing to extract oil, burning oil for precipitation, and filtration and sterilization to obtain the finished soy sauce and carry out bottling. Among them, the fermentation process includes 3 temperature-controlled fermentation stages, and Torulaspora delbrueckii is added; specifically, the temperature control method for the first stage is to control the temperature at 4 - 16 °C for 1 - 25 days, the temperature at 20 - 28 °C for 25 - 30 days, and the temperature at 28 - 30 °C from the 30th day to the 180th day. The Torulaspora delbrueckii is added when 5.1 < pH < 5.4 in the sauce mash, and the inoculation amount of Torulaspora delbrueckii is 10 5 cells / g.

[0066] Among them, the microbial deposit number of Torulopsis sp. CZ1 is CGMCC No.24918; the deposit unit is: China General Microbiological Culture Collection Center; the deposit address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; the deposit time is May 19, 2022.

[0067] Example 3: Provide a method for preparing zero-sugar and low-salt soy sauce. This preparation method includes the following steps:

[0068] S1: Prepare wheat into fermented mash, and inoculate Torulopsis globosa CZ1 during the preparation process. During the process of preparing wheat into fermented mash, the preparation process includes the following steps:

[0069] S11: Fry and crush wheat and then sieve it to obtain wheat flour. During sieving, an 18-mesh sieve is selected for sieving.

[0070] S12: Mix the wheat flour with water, and then add sugar to obtain wheat flour sugar mash. The concentration after mixing wheat flour and water is 0.25 g / ml. The sugar is liquefied sugar, and the addition method is spraying.

[0071] S13: Inoculate the sugar mash with Saccharomyces cerevisiae for fermentation, stop fermentation after 7 days of fermentation to obtain fermented mash. The inoculation amount of Saccharomyces cerevisiae is 10 5 cells / g.

[0072] S2: Prepare the koji for soy sauce. Inoculate Aspergillus oryzae (inoculation amount is 0.1%), and cultivate at 33 °C for 42 h to obtain the koji for soy sauce. The mass ratio of soybeans to wheat is 7:3.

[0073] S3: Mix the fermented mash, additional soy sauce and salt to obtain mixed brine. In the mixed brine, the mass percentage of ethanol is 4%, the ammonia nitrogen content is 0.3 g / 100 mL, the mass percentage of NaCl is 18%; the sugar content of the additional soy sauce is 0.8 g / 100 mL; the mass percentage of salt is 11%; the protein utilization rate reaches 90%.

[0074] S4: Mix the mixed brine with the koji for soy sauce to obtain moromi. The mass ratio of the mixed brine to the koji for soy sauce is 1:1.8.

[0075] S5: Ferment the moromi, and then press to extract oil, heat and precipitate, filter and sterilize to obtain the finished soy sauce and fill it. The fermentation process includes 3 temperature-controlled fermentation stages, and Torulopsis globosa and Torulopsis globosa CZ1 are added. Specifically, the temperature control method for the first stage is to control the temperature at 4-16 °C for 1-25 days, at 20-28 °C for 25-30 days, and at 28-30 °C from the 30th day to the 180th day. Inoculate Torulopsis globosa CZ1 on the 135th day (when the sugar content of Torulopsis globosa CZ in the moromi is less than 16 g / L), and the inoculation amount of Torulopsis globosa CZ1 is 10 4 cells / g of mash; The Saccharomyces rouxii is added when 5.1 < pH < 5.4 in the moromi, and the inoculation amount of Saccharomyces rouxii is 10 5 cells / g.

[0076] The microbial accession number of the aforementioned *Saccharomyces cerevisiae* CZ1 is CGMCC No. 24918; the depository is the China General Microbiological Culture Collection Center; the depository address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; and the deposit date is May 19, 2022.

[0077] Comparative Example 1: A method for preparing soy sauce is provided, the method comprising the following steps:

[0078] Steamed soybeans and roasted wheat were mixed in a ratio of 8:2, and the moisture content was adjusted to 45%. Then, Aspergillus oryzae was inoculated (inoculation amount of 0.1%) and cultured at 33℃ for 42 h to obtain soy sauce koji.

[0079] Soy sauce starter and 22% brine (adjusted to 0.3g / 100mL with added soy sauce) are mixed in a mass-volume ratio of 1:1.8. After thorough mixing, the mixture is pumped into a fermentation tank. The temperature is controlled as follows: 4-16℃ for fermentation days 1-25, 20-28℃ for fermentation days 25-30, and 28-30℃ from day 30 until the end of fermentation.

[0080] After fermentation, the oil is extracted by pressing, sterilized, and then bottled to obtain the finished product.

[0081] The components of the soy sauces obtained in Examples 1-3 and Comparative Example 1 were tested and compared. The sugar content was determined according to GB 5009.8, the salt content according to GB / T 18186, and the protein utilization rate was calculated as (total protein in the actual soy sauce / total protein in the raw materials) × 100%. The results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084] As shown in Table 1, preparing wheat mash first and then fermenting soy sauce mash (Examples 1-3) is more conducive to improving protein utilization and reducing soy sauce salt content compared to Comparative Example 1. Adding *Saccharomyces cerevisiae* CZ1 during the wheat mash preparation stage (S1) results in soy sauce with lower sugar content, thus Example 2 has a lower sugar content than Example 3. Adding *Saccharomyces cerevisiae* CZ1 during both the wheat mash preparation stage (S1) and the fermentation stage (S5) results in the lowest sugar content, and no sugar content was detected in Example 1 using this process.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and descriptions of well-known components, processing techniques, and processes have been omitted to avoid unnecessarily limiting the invention.

Claims

1. A method for preparing zero-sugar, reduced-sodium soy sauce, characterized in that, Includes the following steps: S1: Prepare wheat mash; S2: Preparation of soy sauce koji; S3: Mix the fermented rice wine, added soy sauce and salt to prepare a mixed brine; S4: Mix the mixed brine with the soy sauce starter to obtain soy sauce mash; S5: After fermenting the soy sauce mash, press the oil, boil the oil to settle it, and filter it to remove bacteria to obtain the finished soy sauce; In steps S1 and S5, *Saccharomyces cerevisiae* CZ1 was inoculated. The microbial preservation number of the aforementioned *Saccharomyces cerevisiae* CZ1 is CGMCC No. 24918; The fermentation process in S5 includes three temperature-controlled fermentation stages, and also incorporates *Saccharomyces rouxii* and *Saccharomyces globosa* CZ1. The fermentation process is divided into three stages: the first temperature-controlled fermentation stage lasts 1 to 25 days and the second temperature-controlled fermentation stage lasts 4 to 6 days and the third temperature-controlled fermentation stage lasts until the fermentation is completed. Step S1 includes preparing wheat flour saccharide mash, inoculating the wheat flour saccharide mash with brewer's yeast for fermentation, and inoculating the wheat flour saccharide mash with brewer's yeast at the following time: when the sugar content in the wheat flour saccharide mash is less than 10 g / L, inoculate, and continue fermentation until the sugar content is less than 1 g / L and then stop fermentation. The timing for inoculating *Gnaphalium affine* CZ1 in step S5 is when the sugar content of the fermented mash is less than 16 g / L.

2. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1, characterized in that, In S1, the process of preparing wheat mash includes the following steps: S11: Wheat flour is obtained by roasting, grinding, and sifting wheat. S12: Mix the wheat flour with water, then add sugar to obtain wheat flour syrup; S13: Inoculate the sugar mash with brewing yeast for fermentation. When the sugar content in the sugar mash is less than 10 g / L, inoculate the sugar mash with yeast strain CZ1 and continue fermentation. When the sugar content in the sugar mash is less than 1 g / L, stop fermentation to obtain wine mash.

3. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 2, characterized in that, In the sieving process of S11, an 18-20 mesh sieve is used for sieving. The concentration of wheat flour mixed with water in S12 is 0.2~0.3g / ml, the sugar is liquefied sugar, and it is added by spraying.

4. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 2, characterized in that, The inoculum size of S13 for brewing yeast is 10. 5 ~10 6 The inoculum size for *Saccharomyces cerevisiae* CZ1 is 10 cells / g. 4 ~10 5 per g.

5. A method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1 or 2, characterized in that, S2 soy sauce koji is obtained by soaking and steaming soybeans and then ventilating them for 42-46 hours to make koji. The mass ratio of soybeans to wheat is 7:3 to 8:

2.

6. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1, characterized in that, In the mixed brine of S3, the mass percentage of ethanol is 3.5-5.0%, the ammonia nitrogen content is 0.3-0.6 g / 100 mL, and the mass percentage of NaCl is 16-18%.

7. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1, characterized in that, The mass ratio of the mixed brine to the soy sauce starter in S4 is 1:1.5~2.

8. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1, characterized in that, During the S5 fermentation process, the Saccharomyces rouxii is added when the pH of the moromi is 5.1 < pH < 5.4, and the Torulopsis sp. CZ is added when the sugar content of the moromi is less than 16 g / L. The inoculation amount of Saccharomyces rouxii is 10 5 ~10 6 cells / g, and the inoculation amount of Torulopsis sp. CZ is 10 3 ~10 4 cells / g.

9. The method for preparing a zero-sugar, reduced-sodium soy sauce according to claim 1, characterized in that, The sugar content of the added soy sauce in S3 is less than 1.0g / 100mL; the salt content is less than 12% by mass; and the protein utilization rate is 90% or higher.

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