Method for preparing soybean paste

Abstract

The invention relates to a method for preparing soybean paste. By introducing the step of high-temperature soy sauce mash inactivation in the fermentation process and then adding tetracoccus halophilus with the preservation number of CGMCC No. 26096, the brewing process of the soybean paste disclosed by the invention can obviously reduce the risk of white spots, and is particularly suitable for cooking noodles with soybean paste; the comprehensive sensory indexes of the fried bean paste noodles are improved from multiple dimensions of coloring speed, color effect, stability, sauce flavor and the like.

Description

Technical Field

[0001] The present invention relates to the field of microorganisms. More specifically, it relates to a method for preparing soybean paste using Tetragenococcus halophilus with the preservation number of CGMCC NO. 26096. Background Art

[0002] Soybean paste is one of the four traditional fermented soy products in China. It is rich in nutrition, easy to digest, and has a unique flavor. It is an important condiment in people's daily life. Its appearance and flavor are crucial quality indicators, directly affecting consumers' willingness to purchase.

[0003] White spots often appear during the production of soybean paste. They are composed of supersaturated amino acid crystals mainly tyrosine. The solubility of such substances in water is about 0.45 g / L, and their solubility will further decrease with the increase of salinity. Therefore, once formed, it is very difficult to eradicate. Although the existence of white spots has little impact on product quality, consumers will refuse to buy due to the poor appearance, causing great economic losses to enterprises. So far, how to reduce the generation of white spots is still a technical problem in the soybean paste brewing industry, and there is no efficient method to eliminate white spots in soybean paste.

[0004] In addition, as a common condiment, the biggest use of soybean paste is in cooking. Among them, the traditional special fried sauce noodles use a large amount of soybean paste. The addition of soybean paste can not only increase the nutrition of fried sauce noodles, but also improve the overall taste, making the fried sauce noodles more delicious and the color more attractive.

[0005] In the prior art, attention has been paid to the white spot problem of soybean paste. The Chinese patent application with the application number of 201910295473.1 discloses a brewing process of a sauce embryo for soybean paste: the brewing process of the sauce embryo for soybean paste controls the temperature of the koji material before koji making, and adds high-concentration low-temperature cooling brine to the daqu during the fermentation stage to reduce the protease activity in the sauce mash, thereby inhibiting the generation of white spots in soybean paste. This process suppresses the overall protease activity and will affect the decomposition efficiency of proteins. The Chinese patent application with the application number of 202010252896.8 discloses a method for brewing soybean paste by adding halotolerant bacteria to reduce the content of free tyrosine in the sauce mash. The powder Pichia pastoris culture solution obtained by separation and screening is inoculated during the brewing process of soybean paste, which can reduce the amount of tyrosine in the later stage of fermentation and reduce the risk of white spots in soybean paste. The powder Pichia pastoris obtained by this method may compete with the main flavor-enhancing yeast in the soybean paste for growth and thus affect the flavor of the soybean paste.

[0006] Therefore, so far, it is still a technical problem in the soybean paste brewing industry to produce soybean paste with uniform, bright red appearance, no white spots and excellent flavor, and there is no related efficient method. Summary of the Invention

[0007] The present invention solves the above technical problems in the art by providing a new method for preparing soybean paste.

[0008] Specifically, the present invention relates to the following technical solutions:

[0009] On the one hand, the present invention relates to a method for preparing soybean paste, which includes

[0010] 1) Preparing koji mash;

[0011] 2) Subjecting the prepared koji mash to low-temperature fermentation;

[0012] 3) Inactivating the low-temperature fermented koji mash at high temperature;

[0013] 4) Adding Tetragenococcus halophilus with the preservation number of CGMCC No 26096 for fermentation after cooling; and

[0014] 5) Obtaining the finished soybean paste.

[0015] In one embodiment, step 1) includes:

[0016] a) Treating soybean raw materials, preferably by screening, impurity removal and then high-temperature soaking; and

[0017] b) Mixing the cooked soybean raw materials with flour, preferably in a ratio of 1:0.5 - 0.8;

[0018] c) Making koji, preferably by adding 0.1% - 0.3% Aspergillus oryzae for cultivation;

[0019] d) Mixing the obtained koji material with brine to obtain koji mash, preferably, the ratio of koji material to brine is 1:1.7 - 2.2.

[0020] In one embodiment, 1 - 3% of Tetragenococcus halophilus is added in step 4).

[0021] In one embodiment, the low-temperature fermentation is carried out at 15 - 20°C for 15 - 30 days.

[0022] In one embodiment, the high-temperature inactivation is carried out by keeping the temperature at 70 - 90°C for 30 - 50 minutes.

[0023] In one embodiment, it is cooled to 28 - 35°C after the high-temperature inactivation.

[0024] In one embodiment, the temperature is maintained at 30 - 35°C until the fermentation ends after adding Tetragenococcus halophilus.

[0025] In one embodiment, Saccharomyces rouxii is further added 30 - 40 days after the addition of Tetragenococcus halophilus, preferably 0.5 - 2% of Saccharomyces rouxii is added.

[0026] In one embodiment, the fermentation cycle of step 4) is 60 - 90 days.

[0027] On the other hand, the present invention relates to soybean paste obtained by the above method.

[0028] The Tetragenococcus halophilus added in the method of the present invention was isolated by the applicant from the fermented mash in the early stage (preservation number: CGMCC No 26096, see CN202310035808.2). It can improve the flavor of the fermented mash, and at the same time adapt to decomposing tyrosine in a high - salt environment, inhibit the generation of white spots during the fermentation of soybean paste, and does not produce biogenic amines.

[0029] The preparation method of the soybean paste of the present invention inactivates the fermented mash by high temperature, controls the content of microorganisms during the fermentation process, reduces the competition of other flora for Tetragenococcus halophilus that can decompose tyrosine, and the processing technology is reasonable, the process conditions are simple and easy to control. The prepared soybean paste has a delicious taste, is rich in nutrition, and is not restricted by seasons and regions.

[0030] The brewing process of the soybean paste of the present invention uses the method of consuming free tyrosine in the fermented mash of soybean paste to reduce the tyrosine content, and does not affect the protein decomposition during the fermentation of the fermented mash. Therefore, it can essentially and effectively solve the problem that white spots appear in the shelf life of soybean paste and affect the appearance of soybean paste without affecting the quality of soybean paste.

[0031] The soybean paste prepared by the present invention is used for cooking fried sauce noodles, has a strong sauce flavor, and has a fast coloring speed, bright yellow color, and stable color. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a comparison diagram of the actual effects of soybean paste prepared by the methods of the examples and the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention discloses a preparation method of soybean paste. Specifically, it includes the following steps:

[0034] Step 1. Raw material treatment:

[0035] The soybeans are screened, impurity - removed, and then soaked at a high temperature (50 - 80°C) for 20 - 120 minutes, and set aside.

[0036] Step 2. Koji making:

[0037] The soybeans are cooked by using the method of sterilizing at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.5 - 0.8, and then 0.1% - 0.3% of Aspergillus oryzae is added for koji making. Water is added to adjust the moisture content to 45 - 50%, and it is cultured at 28 - 32°C for 2 - 3 days to obtain the mature koji.

[0038] Step 3: Preparation of enhanced strains

[0039] Tetragenococcus halophilus is used. The Tetragenococcus halophilus is preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, with the Latin name Tetragenococcus halophilus and the preservation number CGMCC No26096. The Tetragenococcus halophilus was previously isolated from the moromi. It can produce rich organic acids to improve the flavor of the moromi. At the same time, it is found that this bacterium can decompose tyrosine in a high-salt environment, inhibit the generation of white spots during fermentation, and does not produce biogenic amines such as tyramine. The liquid medium of Tetragenococcus halophilus is 30 - 50% crude soy sauce, 2 - 4% glucose, 0.5 - 2% yeast extract, and the balance is water; it is statically cultured in the liquid medium at 35°C - 37°C for 3 - 5 days to obtain a bacterial suspension with viable cell count ≥ 10 9 CFU / ml for standby (see CN202310035808.2).

[0040] Step 4: Fermentation

[0041] The koji material prepared in Step 2 is mixed with 20 - 25% brine. The ratio of the mature koji to the brine is 1:1.7 - 2.2. After mixing evenly, the moromi is obtained and pumped into the koji tank for fermentation. In the first 15 days of fermentation, low-temperature fermentation is adopted, and the temperature is controlled at 15 - 20°C. From the 15th to the 30th day, the temperature of the moromi is raised to 70 - 90°C, kept warm for 30 - 50 minutes, and then cooled to 28 - 35°C. Subsequently, 1 - 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi, and the fermentation temperature is maintained at 30 - 35°C until the end of fermentation. Stir it once every 3 days. Additionally, 0.5 - 2% of the culture solutions of Saccharomyces rouxii and Torulopsis globosa are added on the 30th - 40th day of fermentation. The overall fermentation period is 60 - 90 days.

[0042] Step 5: Sterilization:

[0043] The fermented moromi is sterilized to obtain the finished product of soybean paste.

[0044] The following further illustrates the specific implementation of the present invention in combination with examples.

[0045] (1) Determination of amino acids in soy sauce: Refer to the national standard GB 5009.124 - 2016 and use an amino acid analyzer for detection.

[0046] (2) Determination of amino acid nitrogen and total acid: The formaldehyde titration method in GB / T 5009.39—2003 "Analysis Method for Hygienic Standard of Soy Sauce" was adopted.

[0047] (3) Determination of biogenic amines: Detection was carried out with reference to GB 5009.208-2016 "Determination of Biogenic Amines in Foods".

[0048] (4) Sensory evaluation: Randomly select 8 people to form a sensory evaluation group to taste the soybean paste brewed with the examples and comparative examples, and compare and score for color, soy sauce aroma, alcohol and ester aroma, and taste. The scoring range is 1-15 points (with a full score of 15 points). The higher the score, the higher the degree of preference.

[0049] (5) Preparation of fried sauce noodles: Put a little oil in the pot, then put in diced fatty meat, stir-fry until slightly yellow and oil comes out, add soybean paste, stir-fry evenly, and cool for later use. Put the noodles into a boiling water pot and boil for two times. After taking out of the pot, put shredded cucumber and shredded carrot on it and pour the fried sauce on it. Invite professional chefs to evaluate from dimensions such as coloring speed, color, and color stability.

[0050] The yeast extract used in the following examples was purchased from Angel Yeast.

[0051] The crude soy sauce can be prepared by methods well-known in the art. The exemplary method used in the present invention includes: After the soybean meal is steamed at 100 °C for 30 min, it is mixed with flour at a mass ratio of 3:1. After cooling to room temperature, it is inoculated with Aspergillus oryzae koji essence accounting for 0.05% (w / w) of the weight of the soybean meal and cultured at 28 °C for 60 hours to obtain koji; Ferment for about 120 days by the high-salt dilute-state soy sauce brewing method (GB18186-2000), press and filter, and perform heat treatment at 90 °C for 30 min to obtain crude soy sauce.

[0052] The ratios in the examples are all by weight.

[0053] Example 1

[0054] Step 1. Raw material treatment:

[0055] The soybeans are screened and decontaminated, and then soaked at 50 °C for 120 minutes for later use.

[0056] Step 2. Koji making:

[0057] The soybeans are cooked by sterilization at 121 °C for 20 minutes. The cooked soybeans are mixed with flour at 1:0.5 (w / w), and then 0.3% (based on the total weight of flour and soybean raw materials being 100%) of Aspergillus oryzae (CICC 2339) is added for koji making. The water content is adjusted to 50% by adding water, and koji is obtained after culturing at 32 °C for 2 days.

[0058] Step 3: Preparation of enhanced strains

[0059] Use a Tetragenococcus halophilus with a preservation number of CGMCC No 26096. The liquid medium for Tetragenococcus halophilus is 30% crude soy sauce, 4% glucose, 2% yeast extract, and the balance is water; statically culture in the liquid medium at 35°C for 3 days to obtain a bacterial solution with viable cell count ≥ 10 9 CFU / ml of the bacterial strain culture solution for standby.

[0060] Step 4: Fermentation

[0061] Mix the koji material prepared in Step 2 with 23% brine, and the ratio of mature koji to brine is 1:1.7 (W / W). After mixing evenly, obtain the moromi, and transfer it to a koji vat for fermentation. For the first 15 days of fermentation, carry out low-temperature fermentation with the temperature controlled at about 15°C. On the 15th day, raise the temperature of the moromi to 70°C, keep it warm for 50 minutes, then cool it to 30°C. Subsequently, add 1% of the Tetragenococcus halophilus prepared in Step 3 to the moromi, and keep the fermentation temperature at 35°C until the end of fermentation. Additionally, add 0.5% of Saccharomyces rouxii (CICC 1379) on the 30th day of fermentation. The overall fermentation period is 60 days.

[0062] Example 2:

[0063] Step 1. Raw material treatment:

[0064] After screening and impurity removal, soak soybeans at 80°C for 20 minutes for standby.

[0065] Step 2. Koji making:

[0066] Use the method of sterilizing at 121°C for 20 minutes to ripen soybeans. After ripening, mix the soybeans with flour at a ratio of 1:0.8 (w / w), then add 0.3% of Aspergillus oryzae (CICC 2339) to make koji, adjust the moisture content to 45% by adding water, and culture at 30°C for 3 days to obtain mature koji.

[0067] Step 3: Preparation of enhanced bacterial strain

[0068] Use a Tetragenococcus halophilus with a preservation number of CGMCC No 26096. The liquid medium for Tetragenococcus halophilus is 40% crude soy sauce, 2% glucose, 1% yeast extract; statically culture in the liquid medium at 37°C for 5 days to obtain a bacterial solution with viable cell count ≥ 2*10 9 CFU / ml of the bacterial strain culture solution for standby.

[0069] Step 4: Fermentation

[0070] Mix the koji material prepared in Step 2 with 25% brine at a ratio of koji to brine of 1:2.0. After uniform mixing, the moromi is obtained and pumped into the koji pool for fermentation. For the first 15 days of fermentation, low-temperature fermentation is adopted, with the temperature controlled at about 15°C. On the 20th day, the temperature of the moromi is raised to 90°C, held for 30 minutes, and then cooled to 35°C. Subsequently, 2% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi, and the fermentation temperature is maintained at 33°C until the end of fermentation. Additionally, 1% of Saccharomyces rouxii (CICC 1379) is added on the 35th day of fermentation. The overall fermentation period is 80 days.

[0071] Example 3:

[0072] Step 1. Raw material treatment:

[0073] The soybeans are screened, impurity-removed, and soaked at 60°C for 60 minutes, and then reserved for use.

[0074] Step 2. Koji making:

[0075] The soybeans are cooked by sterilization at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.7 (w / w), and then 0.3% of Aspergillus oryzae (CICC 2339) is added for koji making. The water content is adjusted to 47% by adding water, and the koji is cultured at 28°C for 2.5 days to obtain the mature koji.

[0076] Step 3: Preparation of enhanced strains

[0077] A kind of Tetragenococcus halophilus with the preservation number of CGMCC No 26096 is used. The liquid medium of Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract. It is statically cultured in the liquid medium at 36°C for 4 days to obtain the strain culture solution with viable cell count ≥ 3×10 9 CFU / ml for standby.

[0078] Step 4: Fermentation

[0079] Mix the koji material prepared in Step 2 with 20% brine at a ratio of koji to brine of 1:1.8. After uniform mixing, the moromi is obtained and pumped into the koji pool for fermentation. For the first 17 days of fermentation, low-temperature fermentation is adopted, with the temperature controlled at about 15°C. On the 15th day, the temperature of the moromi is raised to 80°C, held for 40 minutes, and then cooled to 33°C. Subsequently, 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi, and the fermentation temperature is maintained at 35°C until the end of fermentation. Additionally, 2% of Saccharomyces rouxii (CICC 1379) is added on the 40th day of fermentation. The overall fermentation period is 90 days.

[0080] Example 4:

[0081] Step 1. Raw material treatment:

[0082] After screening and impurity removal, the soybeans are soaked at 60°C for 60 minutes and set aside.

[0083] Step 2. Koji making:

[0084] The soybeans are cooked using the method of sterilization at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.7 (w / w), and then 0.3% Aspergillus oryzae (CICC 2339) is added for koji making. Water is added to adjust the moisture content to 47%, and koji is obtained after culturing at 28°C for 2.5 days.

[0085] Step 3: Preparation of enhanced strain

[0086] A strain of Tetragenococcus halophilus with a preservation number of CGMCC No 26096 is used. The liquid medium for Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract. It is statically cultured in the liquid medium at 36°C for 4 days to obtain a bacterial suspension with viable cell count ≥ 3×10 9 CFU / ml, and the bacterial suspension is set aside.

[0087] Step 4: Fermentation

[0088] The koji prepared in Step 2 is mixed with 20% brine, and the ratio of koji to brine is 1:1.8. After uniform mixing, the moromi is obtained and transferred to a koji pool for fermentation. In the first 17 days of fermentation, low-temperature fermentation is carried out, and the temperature is controlled at about 15°C. On the 15th day, the temperature of the moromi is raised to 80°C, kept warm for 40 minutes, and then cooled to 33°C. Subsequently, 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi, and the fermentation temperature is maintained at 35°C until the end of fermentation. Additionally, 2% of Saccharomyces rouxii (CDMCC 2.54) is added on the 40th day of fermentation. The overall fermentation period is 90 days.

[0089] Example 5:

[0090] Step 1. Raw material treatment:

[0091] After screening and impurity removal, the soybeans are soaked at 60°C for 120 minutes and set aside.

[0092] Step 2. Koji making:

[0093] The soybeans are cooked using the method of sterilization at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.7 (w / w), and then 0.1% Aspergillus oryzae (CGMCC3.6940) is added for koji making. Water is added to adjust the moisture content to 47%, and koji is obtained after culturing at 28°C for 2.5 days.

[0094] Step 3: Preparation of enhanced strain

[0095] Use a Tetragenococcus halophilus with a preservation number of CGMCC No 26096. The liquid medium for Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract; statically culture in the liquid medium at 36°C for 4 days to obtain a bacterial solution with viable cell count ≥ 3×10 9 CFU / ml of the strain culture solution for standby.

[0096] Step 4: Fermentation

[0097] Mix the koji material prepared in Step 2 with 20% brine, and the ratio of koji to brine is 1:1.8. After mixing evenly, obtain moromi, and transfer it to a koji pool for fermentation. For the first 17 days of fermentation, use low-temperature fermentation with the temperature controlled at about 15°C. On the 15th day, raise the temperature of the moromi to 80°C, keep it warm for 40 minutes, then cool it to 33°C. Subsequently, add 3% of the Tetragenococcus halophilus prepared in Step 3 to the moromi, and keep the fermentation temperature at 35°C until the end of fermentation. Additionally, add 2% of Saccharomyces rouxii (CICC 1379) on the 40th day of fermentation. The overall fermentation period is 90 days.

[0098] Example 6:

[0099] Step 1. Raw material treatment:

[0100] After screening and impurity removal, soak soybeans at 80°C for 60 minutes for standby.

[0101] Step 2. Koji making:

[0102] Use the method of sterilizing at 121°C for 20 minutes to ripen soybeans. After ripening, mix the soybeans with flour at a ratio of 1:0.7 (w / w), then add 0.2% of Aspergillus oryzae (CGMCC3.7043) to make koji, adjust the moisture content to 47% by adding water, and culture at 30°C for 2.5 days to obtain mature koji.

[0103] Step 3: Preparation of enhanced strain

[0104] Use a Tetragenococcus halophilus with a preservation number of CGMCC No 26096. The liquid medium for Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract; statically culture in the liquid medium at 36°C for 4 days to obtain a bacterial solution with viable cell count ≥ 3×10 9 CFU / ml of the strain culture solution for standby.

[0105] Step 4: Fermentation

[0106] Mix the koji material prepared in Step 2 with 25% brine. The ratio of koji to brine is 1:1.8. After uniform mixing, the moromi is obtained and pumped into the koji tank for fermentation. For the first 17 days of fermentation, low-temperature fermentation is adopted, and the temperature is controlled at about 15°C. On the 15th day, the temperature of the moromi is raised to 80°C, held for 40 minutes, cooled to 33°C, and then 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi. The fermentation temperature is maintained at 35°C until the end of fermentation. The total fermentation period is 90 days.

[0107] Example 7:

[0108] Step 1. Raw material treatment:

[0109] The soybeans are screened, decontaminated, and then soaked at 80°C for 60 minutes and set aside.

[0110] Step 2. Koji making:

[0111] The soybeans are cooked by sterilization at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.7 (w / w), and then 0.2% of Aspergillus oryzae (CICC 2339) is added for koji making. The water content is adjusted to 47% by adding water, and koji is obtained after culturing at 30°C for 2.5 days.

[0112] Step 3: Preparation of enhanced strains

[0113] A kind of Tetragenococcus halophilus with the preservation number of CGMCC No 26096 is used. The liquid medium of Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract. It is statically cultured in the liquid medium at 36°C for 4 days to obtain a bacterial suspension with viable cell count ≥ 3×10 9 CFU / ml for standby.

[0114] Step 4: Fermentation

[0115] Mix the koji material prepared in Step 2 with 25% brine. The ratio of koji to brine is 1:1.8. After uniform mixing, the moromi is obtained and pumped into the koji tank for fermentation. For the first 17 days of fermentation, low-temperature fermentation is adopted, and the temperature is controlled at about 15°C. On the 15th day, the temperature of the moromi is raised to 80°C, held for 40 minutes, cooled to 33°C, and then 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi. Additionally, 2% of Saccharomyces rouxii (Angel Yeast SC01) is added on the 40th day of fermentation, and the fermentation temperature is maintained at 35°C until the end of fermentation. The total fermentation period is 90 days.

[0116] Example 8:

[0117] Step 1. Raw material treatment:

[0118] The soybeans are screened, decontaminated, and then soaked at 80°C for 60 minutes and set aside.

[0119] Step 2. Koji making:

[0120] The soybeans are cooked using the method of sterilization at 121°C for 20 minutes. The cooked soybeans are mixed with flour at a ratio of 1:0.7 (w / w), and then 0.2% Aspergillus oryzae (CGMCC 3.1059) is added for koji making. Water is added to adjust the moisture content to 47%, and koji is obtained after culturing at 30°C for 2.5 days.

[0121] Step 3: Preparation of enhanced strains

[0122] A strain of Tetragenococcus halophilus with the preservation number CGMCC No 26096 is used. The liquid medium for Tetragenococcus halophilus is 50% crude soy sauce, 3% glucose, and 0.5% yeast extract; it is statically cultured in the liquid medium at 36°C for 4 days to obtain a bacterial suspension with viable cell count ≥ 3×10 9 CFU / ml as the spare strain culture solution.

[0123] Step 4: Fermentation

[0124] The koji prepared in Step 2 is mixed with 25% brine, and the ratio of koji to brine is 1:1.8. After uniform mixing, the moromi is obtained and pumped into the koji pool for fermentation. Low-temperature fermentation is carried out in the first 17 days, with the temperature controlled at about 15°C. On the 15th day, the temperature of the moromi is raised to 80°C, kept warm for 40 minutes, and then cooled to 33°C. Subsequently, 3% of the Tetragenococcus halophilus prepared in Step 3 is added to the moromi. Additionally, 2% of Saccharomyces rouxii (CGMCC 2.180) is added on the 40th day of fermentation, and the fermentation temperature is maintained at 35°C until the end of fermentation. The overall fermentation period is 90 days.

[0125] Comparative Examples 1 - 6:

[0126] The process of Comparative Example 1 is the same as that of Example 1, but Tetragenococcus halophilus is not added.

[0127] Comparative Example 2 uses Tetragenococcus halophilus CGMCC1.2492, and the process is the same as that of Example 1.

[0128] Comparative Examples 3 - 5 use Tetragenococcus halophilus CICC10469, and the processes correspond to Examples 1 - 3 respectively.

[0129] Comparative Example 6 uses Tetragenococcus halophilus CICC26059, but does not use the moromi heating process, which is consistent with the process in CN202310035808.2.

[0130] Table 1 Differences in Comparative Examples

[0131]

[0132] Comparison of physical and chemical indexes between the examples and the comparative examples:

[0133] Table 2 Comparison results of physical and chemical indexes

[0134] Physical and chemical indexes Total acid (g / 100g) Amino acid nitrogen (g / 100g) Presence of white spots Tyrosine content (mg / kg) Biogenic amines (mg / kg) Example 1 2.17 0.79 None 595 595 Example 2 2.06 0.72 None 611 608 Example 3 1.97 0.79 None 581 601 Example 4 1.99 0.78 None 602 612 Example 5 1.90 0.70 None 586 606 Example 6 1.96 0.76 None 599 598 Example 7 1.91 0.78 None 631 599 Example 8 1.98 0.73 None 608 615 Comparative example 1 1.97 0.57 Yes 1903 582 Comparative example 2 2.32 0.58 Yes 1761 611 Comparative example 3 2.29 0.63 Yes 1899 630 Comparative example 4 2.08 0.59 Yes 1305 592 Comparative example 5 1.95 0.59 Yes 1916 602 Comparative example 6 2.5 0.67 Basically none 680 605

[0135] Comparison of sensory scores between the examples and the comparative examples:

[0136] Table 3 Comparison results of sensory evaluation indexes

[0137]

[0138] Comparison of application effects of the fried sauce noodles:

[0139] Table 4 Comparison results of sensory evaluation of the application of the fried sauce noodles

[0140]

[0141] The actual effect is shown in Figure 1 .

[0142] As can be seen from Table 2, Table 3 and Table 4, the content of amino acid nitrogen, the core index of the soybean paste brewed in Examples 1-8, is more than 10% higher than that of the control group, the content of tyrosine is significantly lower than that of the control group, the biogenic amine index has no difference compared with the control, and there are no white spots in the finished soybean paste. The soybean paste brewing process of the present invention can significantly reduce the risk of white spots, and is especially suitable for the cooking of fried sauce noodles, improving the comprehensive sensory indexes of fried sauce noodles from multiple dimensions such as coloring speed, color effect, stability, and sauce flavor.

[0143] The above data all show that the method of the present invention can be used to prepare soybean paste without white spots, and the operation steps are simple and the stability is good. It can be realized without additional equipment using the normal production line, improving the efficiency of production research. The soybean paste that meets the process requirements also meets the requirements of normal production. Moreover, it is detected that the tyrosine index is significantly reduced. Therefore, the preparation method of the soybean paste of the invention can be used in the production stage.

Claims

1. A method for preparing soybean paste, which comprises 1) preparing koji mash; 2) subjecting the prepared koji mash to low-temperature fermentation; 3) subjecting the low-temperature fermented koji mash to high-temperature inactivation; 4) adding Tetragenococcus halophilus with the preservation number of CGMCC No 26096 for fermentation after cooling; and 5) obtaining the finished soybean paste.

2. The method according to claim 1, wherein step 1) comprises: a) Process the soybean raw materials, preferably after screening and impurity removal, and then soak them at high temperature for processing; and b) After ripening the soybean raw materials, mix them with flour, preferably in a ratio of 1:0.5 - 0.8; c) Make koji, preferably by adding 0.1% - 0.3% Aspergillus oryzae for cultivation to make koji; d) Mix the obtained koji material with brine to obtain moromi, preferably, the ratio of koji material to brine is 1:1.7 - 2.

2.

3. The method according to claim 1 or 2, wherein 1-3% of Tetragenococcus halophilus is added in step 4).

4. The method according to any one of claims 1-3, wherein the low-temperature fermentation is carried out at 15-20 °C for 15-30 days.

5. The method according to any one of claims 1-4, wherein the high-temperature inactivation is carried out by holding at a temperature of 70-90 °C for 30-50 minutes.

6. The method according to any one of claims 1-5, wherein it is cooled to 28-35 °C after the high-temperature inactivation.

7. The method according to any one of claims 1-6, wherein the temperature is maintained at 30-35 °C until the end of fermentation after adding Tetragenococcus halophilus.

8. The method according to any one of claims 1-7, wherein Saccharomyces rouxii is further added 30-40 days after adding Tetragenococcus halophilus, preferably 0.5-2% of Saccharomyces rouxii is added.

9. The method according to any one of claims 1-8, wherein the fermentation period of step 4) is 60-90 days.

10. The soybean paste obtained by the method according to any one of claims 1-9.

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