Brewing method of sugar-free soy sauce

Abstract

The invention discloses a brewing method of sugar-free soy sauce, which comprises the following steps: S1, respectively moistening bean slices, puffed vital gluten and fried wheat with water, uniformly mixing, cooking, cooling, inoculating a composite strain containing composite aspergillus oryzae, rhizopus, mucor and saccharified aroma-enhancing yeast, and culturing to prepare high-quality soy sauce yeast; s2, adding water into the puffed vital gluten, mixing, and inoculating protease and pullulanase to prepare enzymolysis mash; s3, supplementing water to the enzymolysis mash to prepare an enzymolysis mash mixed solution, mixing the enzymolysis mash mixed solution with soy sauce koji, ventilating, stirring and fermenting, and transferring into a fermentation tank for fermenting; and S4, squeezing the fermented soy sauce mash to obtain the low-sugar soy sauce with low sugar content. S5, inoculating the low-sugar soy sauce into rhodotorula mucilaginosa for secondary fermentation, and sterilizing and refining after fermentation to obtain a finished product of sugar-free soy sauce; the taste is delicious, and the total sugar content is 1t; 0.5 g / 100mL, and amino acid nitrogen is greater than or equal to 1.2 g / 100mL; the product disclosed by the invention meets the '0' sugar soy sauce standard specified by GB 28050-2011. The production of the sugar-free soy sauce can be realized on the basis of the existing equipment of a soy sauce factory.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fermentation, and in particular relates to a method for brewing sugar-free soy sauce. Background Art

[0002] With the accelerated pace of modern life and the increase of work pressure, unhealthy diet and lack of exercise have led to the "three highs" problem at a younger age. Sugar-free food has become the first choice for healthy living due to its low sugar or sugar-free characteristics. In particular, consumers with diabetes will become an important consumer group of sugar-free food because they pay more attention to health.

[0003] After inquiry, there is no standard for sugar-free soy sauce in China. According to the relevant provisions of GB 28050-2011 "National Food Safety Standard General Rules for Nutrition Labeling of Pre-packaged Foods": In liquid foods, "0" sugar means that the content of monosaccharides and disaccharides is less than 0.5g / 100mL (that is, the sum of glucose, fructose, maltose, sucrose and lactose. The latest draft for comments of GB 28050 "National Food Safety Standard General Rules for Nutrition Labeling of Pre-packaged Foods" specifically refers to the sum of glucose, fructose, sucrose and maltose).

[0004] More and more companies have begun to research low-sugar and sugar-free soy sauce. For example, the Chinese invention patent for patent application No. CN202110286587.7, a method for brewing low-sugar and zero-additive soy sauce, mainly improves the raw material pretreatment, fermentation process and soy sauce crude oil post-processing process, which can greatly reduce the total sugar content in the soy sauce and control it at a low level, thereby realizing the production of low-sugar soy sauce; the total sugar content of the obtained soy sauce is lower than 1.0g / 100mL, and the amino acid nitrogen content is higher than 1.4g / 100mL. The brewed soy sauce is delicious, bright red in color, and has a strong sauce aroma; the Chinese invention patent for patent application No. CN202311271938.2, a method for preparing zero-sugar and reduced-salt soy sauce, mainly prepares wheat into a wine mash and inoculates Torulopsis CZ1 during the fermentation process to consume sugar, so as to achieve the purpose of preparing low-sugar soy sauce. As for the patent application number CN202210633096.X, a sugar-free asparagus soy sauce and its preparation process, it is to prepare soy sauce without adding exogenous sugar and does not measure the sugar content in the prepared soy sauce. Although the above preparation method can prepare low-sugar soy sauce, it still cannot meet the indicators of sugar-free soy sauce specified in GB 28050-2011 "National Food Safety Standard General Rules for Nutrition Labeling of Prepackaged Foods", and also has the defects of complex process and high equipment investment intensity.

[0005] In view of the two important problems in the current production of sugar-free soy sauce, namely how to obtain high-quality sugar-free soy sauce and the problem of preservation, a simple process method that can control sugar from the fermentation source of soy sauce and maintain the quality of soy sauce is urgently needed. Summary of the invention

[0006] The purpose of the present invention is to design a brewing method for sugar-free soy sauce, and the total sugar content of the soy sauce is less than 0.5g / 100mL and the amino acid nitrogen is ≥1.2g / 100mL by improving the fermentation process. The production of sugar-free soy sauce is realized, and the soy sauce is rich in amino acid nitrogen, delicious, and bright red in color.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for brewing sugar-free soy sauce comprises the following steps: S1: Soybean flakes, puffed gluten powder and roasted wheat are moistened with water and then mixed and steamed. After cooling, composite bacteria containing composite Aspergillus oryzae, Rhizopus, Mucor and saccharification and flavoring koji are inoculated and cultured at 25-28°C for 54-56 hours to prepare high-quality soy sauce koji; S2: adding water to the expanded gluten powder, mixing it with protease and pullulanase to prepare enzymatic mash for later use; S3: After the enzymatic hydrolyzed mash is replenished with water, the enzymatic hydrolyzed mash mixture is mixed with the soy sauce koji material, aerated and stirred for fermentation, and then transferred to a fermentation tank for fermentation; S4: The fermented mash is squeezed to obtain a low-sugar soy sauce with low sugar content; S5: The low-sugar soy sauce obtained in S4 is inoculated with red yeast for secondary fermentation, and after the fermentation, sterilization and refining are performed to obtain a finished product of sugar-free soy sauce, wherein the total sugar content of the sugar-free soy sauce is <0.5g / 100mL, and the amino acid nitrogen is ≥1.2g / 100mL. The red yeast is TS344560.

[0008] Furthermore, after cooking and cooling in S1, four composite strains including Aspergillus oryzae are added: ① the amount of composite Aspergillus oryzae (spore count 50×108 / g) is 0.5-1%; ② the amount of Rhizopus is 1-1.5%; ③ the amount of Mucor is 0.5-2%; ④ the amount of saccharification and flavoring koji is 0.1-0.3%, and the mixture is cultured at 25-28°C for 54-56h; during the koji making process, the moisture and temperature of the koji material are strictly controlled to obtain a high-enzyme activity high-quality soy sauce koji.

[0009] Further, in S1, the composite Aspergillus oryzae strain is a composite strain of Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800, and the mixing ratio of Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800 is 2:3; Furthermore, in S1, the bean flakes, puffed gluten powder and roasted wheat are soaked in water for 8 to 9 minutes respectively, and the soaked bean flakes, puffed gluten powder and roasted wheat are mixed and steamed; the weight ratio of the bean flakes, puffed gluten powder and roasted wheat is: 6:4:0.5 to 7:3:0.5; Further, in S2, the puffed gluten is hydrolyzed at 45-55°C for 22-24h to prepare an enzymatic mash, the solid-liquid ratio of the puffed gluten to water is 1:4-5, and then the amount of pullulanase added is 0.5-2‰, the amount of flavor protease is 2%, the amount of endoprotease is 1%, and the amount of aminopeptidase is 3‰ based on the weight of the puffed gluten; Furthermore, after the enzymatic hydrolysis of the enzymatic mash in S3 is completed, the temperature is lowered to room temperature, and then water is added and mixed, and the enzymatic hydrolysis mash mixture is mixed with the soy sauce koji; the ratio of the enzymatic hydrolysis mash mixture to the soy sauce koji is 2 to 3:1; Furthermore, the fermentation of the sauce mash in S3 is divided into two stages: the early fermentation temperature of the sauce mash is 44-46°C, the duration is 4-5 days, and in the early fermentation stage, 0.4-0.6‰ glutaminase, 5-7‰ high-temperature resistant Saccharomyces cerevisiae, and 1-3‰ aminopeptidase are added according to the volume of the sauce mash; in the later stage, the sauce mash is cooled and supplemented with edible salt with a weight of 8-12%, and 20-30% of the volume of the sauce mash is added. Saccharomyces cerevisiae culture solution is added, and the number of yeasts is 2.2-2.4×10 8 cfu / ml; the fermentation temperature of the mash is 31-34°C, and low-sugar soy sauce is obtained by pressing until the fermentation is completed; the total sugar content of the low-sugar soy sauce is: 0.5-0.98g / 100ml; Furthermore, the amount of red yeast in the S5 low-sugar soy sauce is 10-15% (by volume), (the number of yeast is 0.15-0.18×10 8 cfu / ml); the fermentation temperature of the mash is 31-34°C; after the fermentation, sterilization and refining are carried out to obtain the finished sugar-free soy sauce, the total sugar content of the sugar-free soy sauce is <0.5g / 100mL, and the amino acid nitrogen is ≥1.2g / 100mL.

[0010] The following beneficial effects can be obtained through the above technical solution: The invention introduces composite Aspergillus oryzae, Rhizopus, Mucor and saccharification and flavoring koji into the koji making stage to prepare soy sauce koji material, so that the koji is cultured under low temperature conditions, and then the koji is fermented into sauce mash after the koji making is completed; in the early stage of fermentation, dilute high temperature and salt-free fermentation is adopted, so that a variety of enzyme systems such as very rich proteases, amylases, saccharifying enzymes and the like metabolized by low temperature koji are rapidly decomposed under salt-free and salt-free conditions, and the contamination of miscellaneous bacteria is well controlled; in the post-fermentation, a large dose of Saccharomyces rouxii culture fluid is added in an unconventional manner, so that the yeast is rapidly fermented and rapidly utilizes sugars to proliferate in large quantities, thereby rapidly producing wine; alcohol, polysaccharides, amino acids and polypeptides are produced in the fermentation process, a high-nitrogen sauce mash system is formed, the growth and reproduction of miscellaneous bacteria are effectively inhibited, and the sourness problem of the sauce mash is perfectly controlled in the salt-free fermentation stage; The secondary fermentation uses red yeast to further reduce the sugar content in the soy sauce and greatly improve the sensory quality of the soy sauce, making the oil brighter and clearer, with a richer aroma and more delicious taste. The sugar-free soy sauce obtained by the method of the invention has simple process operation, and the obtained sugar-free soy sauce has strong aroma and delicious taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Process flow chart of sugar-free soy sauce. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 As shown, an embodiment of the present invention provides a method for brewing sugar-free soy sauce, and the method is as follows: S1: Soybean flakes, puffed gluten powder and roasted wheat are moistened with water and then mixed and steamed. After cooling, composite bacteria containing composite Aspergillus oryzae, Rhizopus, Mucor and saccharification and flavoring koji are inoculated and cultured at 25-28°C for 54-56 hours to prepare high-quality soy sauce koji; S2: adding water to the expanded gluten powder, mixing it with protease and pullulanase to prepare enzymatic mash for later use; S3: After the enzymatic hydrolyzed mash is replenished with water, the enzymatic hydrolyzed mash mixture is mixed with the soy sauce koji material, aerated and stirred for fermentation, and then transferred to a fermentation tank for fermentation; S4: The fermented mash is squeezed to obtain a low-sugar soy sauce with low sugar content; S5: The low-sugar soy sauce obtained in S4 is inoculated with red yeast for secondary fermentation, and after the fermentation, sterilization and refining are performed to obtain a finished product of sugar-free soy sauce, wherein the total sugar content of the sugar-free soy sauce is less than 0.5 g / 100 mL, and the amino acid nitrogen is ≥1.2 g / 100 mL. The product number of the red yeast is TS344560.

[0013] After cooking and cooling, the S1 is inoculated with four composite bacteria including Aspergillus oryzae: ① the composite Aspergillus oryzae (spore count 50×108 / g) with a strain amount of 0.5-1%; ② the Rhizopus strain amount of 1-1.5%; ③ the Mucor strain amount of 0.5-2%; ④ the saccharification and flavoring koji strain amount of 0.1-0.3%, and cultured at 25-32°C for 44-56 hours; during the koji making process, the moisture and temperature of the koji material are strictly controlled to obtain a high-enzyme activity high-quality soy sauce koji; In S1, the composite Aspergillus oryzae strain is a composite strain of Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800, and the mixing ratio of Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800 is 2:3; In S1, the bean flakes, puffed gluten powder and fried wheat are respectively cooked for 8 to 9 minutes, and the moistened bean flakes, puffed gluten powder and fried wheat are mixed and steamed; the weight ratio of the bean flakes, puffed gluten powder and fried wheat is: 6:4:0.5 to 7:3:0.5; In S2, the expanded gluten powder is hydrolyzed at 45-55°C for 22-24 hours to prepare an enzymatic mash with a solid-liquid ratio of 1:4-5, and the amount of pullulanase added is 0.5-2‰, the amount of flavor protease is 2%, the amount of endoprotease is 1%, and the amount of aminopeptidase is 3‰; After the enzymatic hydrolysis of the enzymatic mash in S3 is completed, the temperature is lowered to room temperature, and then water is added and mixed, and the enzymatic hydrolysis mash mixture is mixed with the soy sauce koji; the ratio of the enzymatic hydrolysis mash mixture to the soy sauce koji is 2 to 3:1; The fermentation of the sauce mash in S3 is divided into two stages: in the early stage, the fermentation temperature of the sauce mash is kept at 44-46°C, the duration is 4-5 days, the amount of glutaminase added is 0.4-0.6‰, the amount of thermostable Saccharomyces cerevisiae added is 5-7‰, and the amount of aminopeptidase added is 1-3‰; in the later stage, the sauce mash is cooled and supplemented with edible salt with a weight of 8-12%, and the Saccharomyces cerevisiae culture solution with a volume of 20-30% of the sauce mash is added, and the number of yeasts is 2.2-2.4×10 8 cfu / ml; the fermentation temperature of the mash is 31-34°C, and low-sugar soy sauce is obtained by pressing after the fermentation is completed; The amount of red yeast in the S5 low-sugar soy sauce is 10-15% (by volume), (the number of yeast is 0.15-0.18×10 8 cfu / ml); the heat preservation temperature of the sauce mash is 31-34°C; the total sugar content of the low-sugar soy sauce is: 0.5-0.98g / 100ml; Example 1

[0014] (1) Bean flakes, puffed gluten and roasted wheat were used as raw materials in a ratio of 6:4:0.5. After the raw materials were screened, they were soaked in water for 8-9 minutes. After soaking, they were mixed and steamed according to the conventional method and cooled to about 28°C. Four composite strains containing Aspergillus oryzae were inoculated: ① Composite Aspergillus oryzae (spore count 50×10 8 1. The amount of Aspergillus oryzae is 0.6%; 2. The amount of Rhizopus is 1%; 3. The amount of Mucor is 0.5%; 4. The amount of saccharification and flavoring koji is 0.2%, and the mixture is cultured at 25°C for 56 hours; the composite Aspergillus oryzae is a composite strain of AS3.951 Aspergillus oryzae and AS3.800 Aspergillus oryzae, and the mixing ratio of AS3.951 Aspergillus oryzae and AS3.800 Aspergillus oryzae is 2:3; the moisture and temperature of the koji material are strictly controlled during the koji making process; the koji making temperature control requirement is 25°C to obtain a high-quality soy sauce koji with high enzyme activity; (2) Take 1.5 parts of puffed gluten and add 4.5 parts of water, mix them and place them in an enzymatic hydrolysis tank. Then add 2% flavor protease, 1% endoprotease, 3‰ aminopeptidase and 1‰ pullulanase. Perform enzymatic hydrolysis at 55℃ for 24 hours to obtain enzymatic mash for use.

[0015] (3) After the enzymatic hydrolysis of the mash was completed, the temperature was lowered to room temperature, and then water was added and mixed. The enzymatic hydrolysis mash mixture was mixed with soy sauce koji for fermentation; the ratio of the enzymatic hydrolysis mash mixture to the soy sauce koji was 2:1; the initial fermentation temperature of the mash was 45°C, the duration was 5 days, the amount of glutaminase added was 0.5‰, the amount of thermostable Saccharomyces cerevisiae added was 6‰, and the amount of aminopeptidase added was 3‰; in the later stage, the mash was cooled, 8% of edible salt was added, and 20% (by volume) of Saccharomyces cerevisiae culture solution (the number of yeast was 2.2×10 8 cfu / ml); the fermented soy sauce is kept warm at 32°C until the fermentation is completed and the low-sugar soy sauce is obtained by squeezing; the total sugar content of the low-sugar soy sauce is: 0.58g / 100ml; (5) 10% (by volume) of red yeast (yeast count 0.18×10 8 cfu / ml) for secondary fermentation; the fermentation temperature of the sauce mash is 32°C; wherein the red yeast is: TS344560.

[0016] (6) After fermentation, the product is sterilized and refined to obtain a finished sugar-free soy sauce with an amino acid nitrogen content of 1.41 g / 100 ml and a total sugar content of 0.35 g / 100 ml, which meets the "0" sugar soy sauce standard specified in GB 28050-2011. Example 2

[0017] (1) Bean flakes, puffed gluten and roasted wheat were used as raw materials in a ratio of 7:3:0.5. After the raw materials were screened, they were soaked in water for 8-9 minutes. After soaking, they were mixed and steamed according to the conventional method and cooled to about 28°C. Four composite strains containing Aspergillus oryzae were inoculated: ① Composite Aspergillus oryzae (spore count 50×10 8 1. The amount of Aspergillus oryzae is 0.6%; 2. The amount of Rhizopus is 1%; 3. The amount of Mucor is 0.5%; 4. The amount of saccharification and flavoring koji is 0.2%, and the mixture is cultured at 25°C for 56 hours; the composite Aspergillus oryzae is a composite strain of AS3.951 Aspergillus oryzae and AS3.800 Aspergillus oryzae, and the mixing ratio of AS3.951 Aspergillus oryzae and AS3.800 Aspergillus oryzae is 2:3; the moisture and temperature of the koji material are strictly controlled during the koji making process, and the koji making temperature control requirement is 26°C to obtain a high-enzyme activity high-quality soy sauce koji; (2) Take 1.5 parts of puffed gluten and add 4.5 parts of water, mix them and place them in an enzymatic hydrolysis tank. Then add 2% flavor protease, 1% endoprotease, 3‰ aminopeptidase and 1‰ pullulanase. Perform enzymatic hydrolysis at 55℃ for 24 hours to obtain enzymatic mash for use.

[0018] (3) After the enzymatic hydrolysis of the mash was completed, the temperature was lowered to room temperature, and then water was added and mixed. The enzymatic hydrolysis mash mixture was mixed with soy sauce koji for fermentation; the ratio of the enzymatic hydrolysis mash mixture to the soy sauce koji was 2:1; the initial fermentation temperature of the mash was 45°C, the duration was 5 days, the amount of glutaminase added was 0.5‰, the amount of thermostable Saccharomyces cerevisiae added was 6‰, and the amount of aminopeptidase added was 3‰; in the later stage, the mash was cooled, 8% of edible salt was added, and 20% (by volume) of Saccharomyces cerevisiae culture solution (the number of yeast was 2.2×10 8 cfu / ml); the sauce mash is kept warm at 32°C until the fermentation is completed and low-sugar soy sauce is obtained by squeezing; the total sugar content of the low-sugar soy sauce is: 0.93g / 100ml.

[0019] (5) 10% (by volume) of red yeast (yeast count 0.18×10 8 cfu / ml) for secondary fermentation; the fermentation temperature of the sauce mash is 32°C; wherein the red yeast is: TS344560.

[0020] (6) After fermentation, the product is sterilized and refined to obtain a finished sugar-free soy sauce with an amino acid nitrogen content of 1.29 g / 100 ml and a total sugar content of 0.39 g / 100 ml, which meets the "0" sugar soy sauce standard specified in GB 28050-2011.

[0021] Comparative Example:

[0022] (1) Preparation of soy sauce koji: 6 parts of bean flakes and 4 parts of puffed gluten powder were soaked in water for 8-9 minutes respectively, and then the soaked bean flakes and puffed gluten powder were fully mixed. Conventional steaming was used, and the mixture was cooled to 32°C, and then 5‰ AS3.951 Aspergillus oryzae and 0.2% saccharification and flavoring koji were added to make koji. The koji making temperature was 32-34°C, and the koji making time was 42 hours. (2) Preparation of soy sauce koji The fermentation of soy sauce mash is carried out in two stages. In the early stage, 12.5°C brine with a weight of 2 times the total weight of bean flakes and puffed gluten powder is added, and 6‰ of the thermostable Saccharomyces cerevisiae is added for heat preservation and fermentation for 5 days at a temperature of 45°C. In the later stage, the soy sauce mash is cooled to 32°C, 8% (by total weight) of edible salt is added, and after being stirred evenly, 2% (by volume) of Saccharomyces cerevisiae culture solution (the number of yeast is 2.2×10 8 cfu / ml) and kept at 32℃ until the fermentation was completed; (3) After the soy mash is fermented for 120 days, it is pressed, filtered, sterilized and refined to obtain soy sauce.

[0023] The products of the sugar-free soy sauce preparation example test were tested for their amino acid nitrogen (AN), total sugar and total nitrogen (TN) contents. The results are shown in Table 1.

[0024] Table 1, test data and sensory index evaluation of soy sauce prepared in specific embodiments of the present invention Through the embodiments and the control examples, it is shown that the present invention can prepare sugar-free soy sauce, which is different from conventional fermentation in that: 1. High-quality soy sauce koji with high enzyme activity is obtained by using multiple strains of bacteria to make koji at low temperature; 2. By preparing the enzymatic hydrolysate before fermentation, multiple enzymes work synergistically to promote the full hydrolysis of amylopectin, so that the Saccharomyces rouxii can quickly utilize the decomposed sugars during the fermentation process to proliferate rapidly, and produce alcohol to prevent the soy sauce from being corrupted; 3. Rhodotorula can utilize multiple carbon sources and nitrogen sources for fermentation, further reduce the sugar content of soy sauce and increase the red index of soy sauce, reduce the color rate, thereby achieving the goal of sugar-free soy sauce, while improving the color and clarity of soy sauce, making the aroma more intense and the taste more delicious.

[0025] The above are all preferred embodiments of the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, various equivalent modifications to the present invention belong to the protection scope of the claims attached to this application.

Claims

1. A method for brewing sugar-free soy sauce, characterized in that: The method is as follows: S1: Soybean flakes, puffed gluten powder and roasted wheat are moistened with water and then mixed evenly for steaming. After cooling, composite bacteria containing composite Aspergillus oryzae, Rhizopus, Mucor and saccharification and flavoring koji are inoculated for cultivation to prepare high-quality soy sauce koji; S2: adding water to the expanded gluten powder and adding protease and pullulanase to prepare enzymatic mash; S3: After the enzymatic hydrolyzed mash is replenished with water, the enzymatic hydrolyzed mash mixture is mixed with the soy sauce koji material, aerated and stirred for fermentation, and then transferred to a fermentation tank for fermentation; S4: The fermented mash is squeezed to obtain a low-sugar soy sauce with low sugar content; S5: The low-sugar soy sauce obtained in S4 is inoculated with red yeast for secondary fermentation. After the fermentation, the low-sugar soy sauce is sterilized and refined to obtain a finished sugar-free soy sauce. The total sugar content of the sugar-free soy sauce is <0.5g / 100mL, and the amino acid nitrogen is ≥1.2g / 100mL. The red yeast is TS344560.

2. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: The soybean meal after cooking and cooling in S1 is inoculated with the composite bacteria and cultured at 25-28°C for 54-56h. The moisture and temperature of the koji are strictly controlled during the koji making process to obtain a high-quality soy sauce koji with high enzyme activity.

3. The brewing method of a sugar-free soy sauce according to claim 1 or 2, characterized in that: The composite bacteria in S1 include composite Aspergillus oryzae with a bacterial species amount of 0.5-1%, Rhizopus with a bacterial species amount of 1-1.5%, Mucor with a bacterial species amount of 0.5-2%, and saccharification and flavoring koji with a bacterial species amount of 0.1-0.3%.

4. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: The composite Aspergillus oryzae in S1 includes Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800, and the mixing ratio of Aspergillus oryzae AS3.951 and Aspergillus oryzae AS3.800 is 2:

3.

5. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: In S1, the bean flakes, puffed gluten powder and roasted wheat are soaked in water for 8 to 9 minutes respectively, and the soaked bean flakes, puffed gluten powder and roasted wheat are mixed and steamed; the weight ratio of the bean flakes, puffed gluten powder and roasted wheat is: 6:4:0.5 to 7:3:0.

5.

6. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: In the enzymatic hydrolysis process of the puffed gluten in S2, water is added at a solid-liquid ratio of 1:4-5, and then 0.5-2‰ pullulanase, 2% flavor protease, 1% endoprotease, and 3‰ aminopeptidase are added according to the weight of the puffed gluten, and enzymatic hydrolysis is carried out at 45-55°C for 22-24h to prepare enzymatic mash.

7. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: After the enzymatic hydrolysis of the enzymatic mash in S3 is completed, the temperature is lowered to room temperature, and then water is added and mixed evenly, and then mixed with the soy sauce koji; the ratio of the soy sauce koji to the enzymatic hydrolysis mash mixture is 2-3:

1.

8. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: The fermentation of the sauce mash in S3 is divided into two stages: in the first stage, 0.4-0.6‰ glutaminase, 5-7‰ thermostable Saccharomyces cerevisiae, and 1-3‰ aminopeptidase are added to the sauce mash by volume at the beginning of the fermentation, and then the fermentation is kept warm; the warm temperature is 44-46°C, and the warm time is 4-5 days; in the second stage, the sauce mash fermented in the first stage is cooled to 31-34°C, and then edible salt is added at 8-12% of the weight of the sauce mash, and 20-30% of Saccharomyces cerevisiae culture solution is added by volume of the sauce mash, and the number of yeasts is 2.2-2.4×10 8 cfu / ml; keep warm at 31-34℃ for conventional fermentation, and after fermentation, squeeze to obtain low-sugar soy sauce with a total sugar content of 0.5-0.95g / 100ml.

9. The method for brewing sugar-free soy sauce according to claim 1, characterized in that: The S5 low-sugar soy sauce secondary fermentation process needs to be inoculated with red yeast; the amount of red yeast inoculated is: 10-15% by volume of the low-sugar soy sauce, and the number of red yeast is 0.15-0.18×10 8 cfu / ml; the secondary fermentation temperature is 31-34℃; after the fermentation, the finished sugar-free soy sauce is obtained through sterilization, filtration and refining, which has bright red color, delicious taste, total sugar content <0.5g / 100mL, and amino acid nitrogen ≥1.2g / 100mL; it meets the "0" sugar soy sauce standard specified in GB 28050-2011.

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