A method for improving the efficiency of soy sauce tank fermentation

Abstract

The application discloses a method for improving the fermentation efficiency of soy sauce pool type fermentation, which is characterized by the following steps: using the self-source microorganism in the fermentation tank to carry out fermentation outside the fermentation tank, combining with the fermentation liquid of Lactobacillus reuteri for synergistic fermentation, and then returning the fermentation liquid to the fermentation tank for pouring and utilization, so as to realize the promotion of the self-source microorganism in the fermentation tank to the soy sauce fermentation. The self-source microorganism is fermented and cultured by reducing the salinity outside the fermentation tank and adding a proper amount of starch raw material, and the fermentation liquid with high activity of protease can be prepared in a short time, which is returned to the fermentation tank for pouring and utilization, so as to improve the degree and efficiency of protein hydrolysis in the fermentation tank. The Lactobacillus reuteri uses the fermentation liquid of the soy sauce mash in the fermentation tank as the basic nutrient source and ferments together with a proper amount of white granulated sugar to produce the fermentation liquid with the function of inhibiting Escherichia coli, so as to resist the Escherichia coli pollution in the fermentation process of the self-source microorganism outside the fermentation tank, guarantee the safety of the returned pouring fermentation liquid, and further improve the production efficiency of the soy sauce pool type fermentation technology.

Description

TECHNICAL FIELD

[0001] The present application relates to a soy sauce pool fermentation process, in particular to a method for improving the efficiency of soy sauce pool fermentation. BACKGROUND

[0002] Soy sauce brewing has a history of more than 3,000 years, and has been produced in traditional small workshops for a long time. The brewing technology is basically inherited, and lacks the guidance of modern science. Therefore, the brewing technology has been stagnant for a long time.

[0003] With the development of modern science, especially the significant improvement in microbiology, people have some understanding and gradually clear understanding of the microbiological mechanism of brewing. As a result, the soy sauce brewing technology has developed rapidly, and the production level has been greatly improved. The fermentation container has developed from small jars to large pools and tanks, and the fermentation capacity has increased by several tens or even hundreds of times. Correspondingly, the related scientific and technological research on brewing has also developed rapidly, especially the research on the utilization rate and conversion rate of protein resources and the flavor quality. A large amount of investment has been made to improve the utilization of resources and stabilize the flavor quality.

[0004] In recent years, there have been many researches on improving the utilization rate and conversion rate of soybean protein resources, and improving the fermentation efficiency and quality of soy sauce. For example, the Chinese invention patent with the publication number CN109463713A (the patent name is: a multi-strain fermentation process for improving the flavor of soy sauce), which optimizes the fermentation conditions of pneumatic stirring, and inoculates Weissella, salt-tolerant Pediococcus pentosaceus, Saccharomyces rouxii, and Torulopsis glabrata at different stages of fermentation to realize multi-strain synergistic fermentation, improve the utilization rate of raw materials and the conversion rate of amino acid nitrogen, and improve the flavor and quality of soy sauce.

[0005] For another example, the Chinese invention patent with the publication number CN111329034A (the patent name is: a method for improving the quality of soy sauce), which produces high-salt dilute soy sauce through double-strain synergistic fermentation, and appropriately adds double-strain composed of Saccharomyces rouxii and Haloterrigena quadruplicata during the fermentation process of soy sauce mash. The soy sauce produced by double-strain synergistic fermentation has rich soy sauce aroma, thick ester aroma, and sufficient umami. The content of furanone, a flavor component in soy sauce, is 7.4 times that of the control without adding strains, and the total content of volatile flavor substances is 2.4 times that of the control. It has important significance for large-scale production of high-quality soy sauce.

[0006] At present, the technology and process for improving the utilization rate and conversion rate of soybean protein resources, and improving the fermentation efficiency and product quality are mostly achieved through the addition of additional strains for synergistic fermentation, without considering the use of self-source microorganisms in the fermentation pool. The fermentation effect of self-source microorganisms outside the fermentation pool is returned to the soy sauce mash to improve the fermentation efficiency. SUMMARY

[0007] In order to effectively improve the utilization rate and conversion rate of soybean protein resources in the fermentation process of soy sauce, and to improve the fermentation efficiency and obtain high-quality products, the application provides a method for improving the fermentation efficiency of soy sauce pool.

[0008] The application realizes the promotion of soy sauce fermentation by self-source microorganisms in the fermentation tank, improves the utilization rate of protein and the conversion rate of amino acids, reduces the precipitation, and improves the flavor quality of soy sauce products.

[0009] The application realizes the technical scheme as follows:

[0010] A technical method for effectively improving the fermentation efficiency of soy sauce pool, based on the process technology of mature soy sauce koji in the fermentation process in the fermentation tank, comprising the following steps:

[0011] Step one: the mature soy sauce koji is mixed with salt water with a concentration of 19%±1%(w / w) in the fermentation tank according to a weight ratio of 1:2.2 to form a dilute moromi, and the fermentation is started.

[0012] Step two: after a period of fermentation, the surface material of the moromi is taken as a source of self-source microorganisms, and is mixed with corn starch paste liquid and Lactobacillus reuteri fermentation liquid in a certain proportion and content in the fermentation tank, and then the self-source microbial fermentation liquid is obtained by fermentation; the prepared self-source microbial fermentation liquid is returned and poured into the moromi.

[0013] Step three: thereafter, the process of step two is repeated every certain period of time, and the frequency of repeating step two is three to four times in total, and the moromi is finally fermented to maturity. The liquid part of the material is discharged to obtain high-quality soy sauce.

[0014] The Lactobacillus reuteri fermentation liquid of step two is prepared by adding white granulated sugar, water and inoculating Lactobacillus reuteri fermentation based on the moromi fermentation liquid as the basic nutrient source, and the fermentation culture medium is composed of the following components according to the weight ratio:

[0015] Moromi fermentation liquid: 34%(w / w)

[0016] White granulated sugar: 6%(w / w)

[0017] Water: 60%(w / w)

[0018] Lactobacillus reuteri: inoculation amount is 10 6 CFU / mL (based on the volume of the culture medium).

[0019] The fermentation process conditions are as follows: the soy sauce mash fermentation liquor, white granulated sugar and water are mixed and dissolved, then heated to 93±2 DEG C and kept for 20 minutes, then cooled to 37±1 DEG C, inoculated with Lactobacillus reuteri, and kept at 37±1 DEG C for 12 hours for fermentation, then boiled for 5 minutes for sterilization treatment, so that the Lactobacillus reuteri fermentation liquor can be obtained.

[0020] The prepared Lactobacillus reuteri fermentation liquor has a pH value of 4.3±0.2, a total acid content of 1.6±0.3 g / 100 mL (calculated as lactic acid), and a significant inhibitory effect on Escherichia coli, and the diameter of the inhibition zone is required to be greater than 12 mm in the inhibition zone test.

[0021] In step two, the self-source microorganism refers to the microorganism cultivated in the material with a thickness of 1 cm on the surface of the fermentation tank mash, which is from the soy sauce koji and the environment of the fermentation tank, and which survives under the high-salt condition of the mash and is screened in the fermentation process of the mash.

[0022] In step two, the self-source microorganism fermentation liquor has the following raw material composition according to the weight percentage:

[0023] Self-source microorganism: 18% to 32% (w / w)

[0024] Corn starch gelatinized liquid: 62% to 76% (w / w)

[0025] Lactobacillus reuteri fermentation liquor: 6% (w / w)

[0026] The concentration of the corn starch gelatinized liquid is 4.6% to 5.6% (w / w).

[0027] Then, the fermentation is carried out in the fermentation tank at 37±1 DEG C for 16 to 28 hours, and the protease activity at the end of the fermentation reaches more than 700 U / mL, and the sum of the acid protease activity and the neutral protease activity is not less than 650 U / mL.

[0028] In step three, the frequency of the repeated operation of step two and the fermentation time are as follows: the production time is from the middle of April to the middle of October every year, the frequency is totally three times, and the fermentation time is 70±3 days; the frequency of the rest of the production time is totally four times, and the fermentation time is 90±3 days.

[0029] Compared with the prior art, the present application has the following advantages and effects:

[0030] The pool fermentation is a relatively open fermentation mode of soy sauce, and the height (thickness) of the material in the fermentation pool is generally about 1 meter. However, the surface area of the fermented mash is large, and a large number of microorganisms outside the fermentation pool gradually fall into the surface of the mash. Together with the microorganisms from the soy sauce koji, the microorganisms are subjected to the high-salt condition, so that most of the microorganisms that are not resistant to high-salt environment die, and only a small part of the salt-tolerant and adapted microorganisms for soy sauce fermentation, referred to as self-source microorganisms, are left. These microorganisms participate in the fermentation of the soy sauce mash, and can improve the fermentation effect and efficiency of the soy sauce.

[0031] The self-source microorganisms are used for fermentation outside the fermentation pool to prepare a fermentation liquor with high protease activity. The fermentation liquor is returned and poured onto the mash to enhance the proteolysis capacity of the mash and improve the utilization rate and conversion rate of soybean protein. At the same time, the self-source microorganism activity is improved by the self-source microorganism fermentation liquor, and the soy sauce prepared by the traditional soy sauce brewing process has the quality and characteristics of traditional soy sauce, such as good color, strong aroma, and thick taste.

[0032] In order to improve the fermentation speed of the self-source microorganisms, the salt content in the culture medium for the self-source microorganism fermentation outside the fermentation pool is appropriately reduced by adding corn starch paste, so that the salt content is reduced to 3.5% to 6.0% (w / w), which is beneficial to the effective and high-speed fermentation. However, after the salt content is reduced, the fermentation system is easily contaminated by E. coli in the environment, which causes the self-source microorganism fermentation liquor to have an odor and reduces the production of protease. The Lactobacillus reuteri fermentation liquor is prepared by using the mash fermentation liquor as the main raw material, adding an appropriate amount of white granulated sugar, sterilizing, inoculating Lactobacillus reuteri, and incubating and fermenting. The fermentation liquor contains lactic acid, which has acidic taste characteristics, and also produces E. coli inhibition substances. Therefore, by adding the Lactobacillus reuteri fermentation liquor for fermentation, the growth of the possible contaminated E. coli is inhibited, and the fermentation environment is provided with moderate acidity, which is beneficial to the secretion and production of neutral protease and acid protease. DETAILED DESCRIPTION

[0033] The application will be further specifically and in detail described below with reference to specific examples.

[0034] Example 1

[0035] An effective technical method for improving the fermentation efficiency of soy sauce pool, based on the process technology of mature soy sauce koji fermentation in the fermentation pool, includes the following steps (the production time is taken as mid-May as an example):

[0036] Step one: The mature soy sauce koji is mixed with salt water with a concentration of 19% ± 1% (w / w) in the fermentation pool at a weight ratio of 1:2.2 to form a dilute mash, and the fermentation is started.

[0037] Step two: at the 10th day of fermentation, the material with a thickness of 1 cm on the surface of the mash in the fermentation tank was taken as a source of microorganisms, and was mixed with corn starch paste liquid and Lactobacillus reuteri fermentation liquid in a certain proportion in a fermentation tank, and then was fermented to obtain a self-source microbial fermentation liquid, and the obtained self-source microbial fermentation liquid was returned and sprayed on the mash; the specific operation process is described as follows:

[0038] (1) Preparation of Lactobacillus reuteri fermentation liquid:

[0039] The Lactobacillus reuteri fermentation liquid is prepared by adding white granulated sugar and water to the mash fermentation liquid and inoculating Lactobacillus reuteri for fermentation, and the fermentation medium is composed of the following components by weight:

[0040] Mash fermentation liquid: 34% (w / w)

[0041] White granulated sugar: 6% (w / w)

[0042] Water: 60% (w / w)

[0043] Lactobacillus reuteri: inoculation amount is 10 6 CFU / mL (based on the volume of the medium).

[0044] The fermentation process conditions are as follows: after the mash fermentation liquid, white granulated sugar and water are mixed and dissolved, heating to 93±2℃ for 20 minutes, then cooling to 37±1℃, inoculating Lactobacillus reuteri, and incubating at 37±1℃ for 12 hours, then boiling for 5 minutes for sterilization treatment, then the Lactobacillus reuteri fermentation liquid can be obtained.

[0045] The prepared Lactobacillus reuteri fermentation liquid has a pH value of 4.3±0.2, a total acid content of 1.6±0.3 g / 100 mL (calculated as lactic acid), and a significant inhibitory effect on Escherichia coli, and the diameter of the inhibition zone is required to be greater than 12 mm by using the inhibition zone test method.

[0046] (2) Acquisition of self-source microorganisms:

[0047] The microorganisms cultivated in the material with a thickness of 1 cm on the surface of the mash in the fermentation tank are from the soy sauce koji and the environment of the fermentation tank, and can survive under high-salt conditions in the mash, and are obtained by high-salt screening during the mash fermentation process, therefore, the material with a thickness of 1 cm on the surface of the mash is taken as the self-source microorganisms, and the percentage of the self-source microbial material in the total amount of the material in the fermentation tank is 1.1±0.1% (w / w).

[0048] (3) Preparation of self-source microbial fermentation liquid

[0049] According to the weight percentage, the medium raw material composition is as follows:

[0050] Self-source microorganism: 18% (w / w)

[0051] Corn starch gelatinized liquid: 76% (w / w)

[0052] Lactobacillus reuteri fermentation liquid: 6% (w / w)

[0053] The concentration of the corn starch gelatinized liquid is 4.6% (w / w).

[0054] Then, the fermentation is carried out in a fermentation tank at 37±1℃ for 28 hours, and the protease activity at the end of fermentation is determined to be above 700 U / mL, and the sum of the acid protease activity and the neutral protease activity is not less than 650 U / mL.

[0055] The prepared self-source microorganism fermentation liquid is returned and poured into the soy sauce mash.

[0056] Step three: thereafter, the process of step two is repeated at 25 days and 45 days of fermentation, respectively, so that the frequency of repeating the process of step two is 3 times in total, and the soy sauce mash is finally fermented to maturity after 70±3 days of fermentation. The liquid material is discharged to obtain high-quality soy sauce.

[0057] Example 2:

[0058] A technical method for effectively improving the fermentation efficiency of a soy sauce pool, based on the process technology of mature soy sauce koji in the fermentation process in the fermentation pool, includes the following steps (taking the end of September as an example):

[0059] Step one: the mature soy sauce koji is mixed with salt water with a concentration of 19%±1% (w / w) in the fermentation pool at a weight ratio of 1:2.2 to form a dilute soy sauce mash, and the fermentation is started.

[0060] Step two: at 10 days of fermentation, the material with a thickness of 1 cm on the surface of the fermentation pool is taken as the source of self-source microorganisms, and is mixed with corn starch gelatinized liquid and Lactobacillus reuteri fermentation liquid in a certain proportion in a fermentation tank to obtain self-source microorganism fermentation liquid, and the prepared self-source microorganism fermentation liquid is returned and poured into the soy sauce mash; the specific operation process is described as follows:

[0061] (1) Preparation of Lactobacillus reuteri fermentation liquid:

[0062] The Lactobacillus reuteri fermentation liquid is prepared by adding white granulated sugar and water to the soy sauce mash fermentation liquid and inoculating Lactobacillus reuteri for fermentation, and the fermentation medium is composed of the following components according to weight ratio:

[0063] Soy sauce mash fermentation liquid: 34% (w / w)

[0064] White granulated sugar: 6% (w / w)

[0065] Water: 60% (w / w)

[0066] Lactobacillus reuteri: inoculation amount is 10 6 CFU / mL (based on the volume of medium).

[0067] The fermentation process conditions are as follows: after the soy sauce fermentation liquor, white granulated sugar and water are mixed and dissolved, heating to 93±2℃ for 20 minutes, then cooling to 37±1℃, inoculating Lactobacillus reuteri, and incubating at 37±1℃ for 12 hours for fermentation, then boiling for 5 minutes for sterilization treatment, then Lactobacillus reuteri fermentation liquor can be obtained.

[0068] The pH value of the prepared Lactobacillus reuteri fermentation liquor is 4.3±0.2, the total acid content is 1.6±0.3g / 100mL (calculated as lactic acid), and it has a significant inhibitory effect on Escherichia coli, which is required to be tested by the inhibition zone test method, and the diameter of the inhibition zone is greater than 12mm.

[0069] (2) Acquisition of self-source microorganisms:

[0070] The microorganisms cultivated in the 1cm-thick surface layer of the fermentation tank soy sauce are microorganisms from the soy sauce koji and the fermentation tank environment, which survive under high-salt conditions and are obtained through high-salt screening during the soy sauce fermentation process. Therefore, the 1cm-thick surface layer of the soy sauce is scraped as self-source microorganisms, and the percentage of the self-source microorganism material in the total fermentation tank material is 1.1±0.1% (w / w).

[0071] (3) Preparation of self-source microorganism fermentation liquor

[0072] According to the weight percentage, the composition of the culture medium raw materials is as follows:

[0073] Self-source microorganisms: 32% (w / w)

[0074] Corn starch gelatinized liquid: 62% (w / w)

[0075] Lactobacillus reuteri fermentation liquor: 6% (w / w)

[0076] Among them, the concentration of corn starch gelatinized liquid is between 5.6% (w / w).

[0077] Then ferment in the fermentation tank at 37±1℃ for 16 hours, and the protease activity at the end of fermentation should reach more than 700U / mL, and the sum of the activities of acid protease and neutral protease should not be less than 650U / mL.

[0078] The prepared self-source microorganism fermentation liquor is returned and sprayed on the soy sauce.

[0079] Step three: thereafter, at 25 days and 45 days of fermentation, the process of step two is repeated, so that the frequency of repeating step two is 3 times in total, and after 70±3 days of fermentation, the final mash is fermented to maturity. The liquid material is discharged to produce high-quality soy sauce.

[0080] Example 3:

[0081] A technical method for effectively improving the fermentation efficiency of soy sauce tank fermentation is based on the process technology of mature soy sauce koji fermentation in a fermentation tank, which includes the following steps (the production time is taken as an example in early November):

[0082] Step one: mix the mature soy sauce koji and the salt water with a concentration of 19%±1% (w / w) in a fermentation tank according to a weight ratio of 1:2.2 to form a dilute mash, and start fermentation.

[0083] Step two: at 15 days of fermentation, take the material with a thickness of 1 cm on the surface of the fermentation tank as a source of microorganisms, and mix it with corn starch paste and Lactobacillus reuteri fermentation broth in a fermentation tank according to a certain proportion, then ferment to obtain a self-source microbial fermentation broth, and return the prepared self-source microbial fermentation broth to the mash; the specific operation process is described as follows:

[0084] (1) Preparation of Lactobacillus reuteri fermentation broth:

[0085] The Lactobacillus reuteri fermentation broth is prepared by adding white sugar and water to the mash fermentation broth and inoculating Lactobacillus reuteri for fermentation. According to the weight ratio, the fermentation medium is composed of:

[0086] Mash fermentation broth: 34% (w / w)

[0087] White sugar: 6% (w / w)

[0088] Water: 60% (w / w)

[0089] Lactobacillus reuteri: inoculation amount is 10 6 CFU / mL (based on the volume of the medium).

[0090] The fermentation process conditions are as follows: mix and dissolve the mash fermentation broth, white sugar and water, heat to 93±2℃ for 20 minutes, then cool to 37±1℃, inoculate Lactobacillus reuteri, and incubate at 37±1℃ for 12 hours, then boil for 5 minutes for sterilization treatment, then the Lactobacillus reuteri fermentation broth can be obtained.

[0091] The prepared Lactobacillus reuteri fermentation broth has a pH value of 4.3±0.2 and a total acid content of 1.6±0.3 g / 100 mL (calculated as lactic acid), and has a significant inhibitory effect on Escherichia coli. The inhibition zone test method is used to test that the diameter of the inhibition zone is greater than 12 mm.

[0092] (2) Acquisition of self-source microorganisms:

[0093] The microorganisms in the 1 cm thick layer of the fermented mash are the microorganisms from the soy sauce koji and the environment of the fermentation tank, which survive under the high-salt condition of the mash and are screened by high salt during the fermentation process of the mash. Therefore, the 1 cm thick layer of the mash is scraped as the self-source microorganisms, and the amount of the self-source microorganism material accounts for 1.1 ± 0.1% (w / w) of the total amount of the material in the fermentation tank.

[0094] (3) Preparation of self-source microorganism fermentation broth

[0095] According to the weight percentage, the raw material composition of the culture medium is as follows:

[0096] Self-source microorganisms: 25% (w / w)

[0097] Corn starch paste liquid: 69% (w / w)

[0098] Lactobacillus reuteri fermentation broth: 6% (w / w)

[0099] The concentration of the corn starch paste liquid is between 5.1% (w / w).

[0100] Then, the fermentation is carried out in the fermentation tank at 37 ± 1°C for 22 hours, and the protease activity at the end of fermentation should reach more than 700 U / mL, and the sum of the activities of the acid protease and the neutral protease is not less than 650 U / mL.

[0101] The prepared self-source microorganism fermentation broth is returned and sprayed on the mash.

[0102] Step three: thereafter, the process of step two is repeated at 30 days, 50 days and 75 days of fermentation, respectively, so that the frequency of repeating step two is a total of 4 times, and after 90 ± 3 days of fermentation, the final mash is matured. The liquid material is discharged to produce high-quality soy sauce.

[0103] Example 4:

[0104] A technical method for effectively improving the fermentation efficiency of a soy sauce tank, based on the process technology of mature soy sauce koji during the fermentation process in the fermentation tank, includes the following steps (the production time is taken as an example in mid-March):

[0105] Step one: the mature soy sauce koji is mixed with the salt water with a concentration of 19% ± 1% (w / w) in the fermentation tank at a weight ratio of 1:2.2 to form a dilute mash, and the fermentation is started.

[0106] The fermentation tank is mixed to form a dilute mash, and the fermentation is started.

[0107] Step two: after 15 days of fermentation, the material with a thickness of 1 cm on the surface of the fermented mash in the fermentation tank was taken as a source of microorganisms, and was mixed with corn starch paste liquid and Lactobacillus reuteri fermentation liquid in a certain proportion in a fermentation tank, and then was fermented to obtain a self-source microbial fermentation liquid, and the obtained self-source microbial fermentation liquid was returned and sprayed on the mash; the specific operation process is described as follows:

[0108] (1) Preparation of Lactobacillus reuteri fermentation liquid:

[0109] The Lactobacillus reuteri fermentation liquid was prepared by adding white granulated sugar and water to the mash fermentation liquid and inoculating Lactobacacillus reuteri for fermentation, and the fermentation medium was composed of the following components by weight:

[0110] Mash fermentation liquid: 34% (w / w)

[0111] White granulated sugar: 6% (w / w)

[0112] Water: 60% (w / w)

[0113] Lactobacillus reuteri: inoculation amount of 10 6 CFU / mL (based on the volume of the medium).

[0114] The fermentation process conditions were as follows: after the mash fermentation liquid, white granulated sugar and water were mixed and dissolved, heating to 93±2℃ for 20 minutes, then cooling to 37±1℃, inoculating Lactobacillus reuteri, and incubating at 37±1℃ for 12 hours, then boiling for 5 minutes for sterilization treatment, the Lactobacillus reuteri fermentation liquid was obtained.

[0115] The prepared Lactobacillus reuteri fermentation liquid had a pH value of 4.3±0.2, a total acid content of 1.6±0.3 g / 100 mL (calculated as lactic acid), and a significant inhibitory effect on Escherichia coli, and the diameter of the inhibition zone was required to be greater than 12 mm by using the inhibition zone test method.

[0116] (2) Acquisition of self-source microorganisms:

[0117] The microorganisms cultivated in the material with a thickness of 1 cm on the surface of the mash in the fermentation tank were from the soy sauce koji and the environment of the fermentation tank, and survived under the high-salt condition of the mash, and were obtained by high-salt screening during the mash fermentation process, therefore, the material with a thickness of 1 cm on the surface of the mash was taken as the self-source microorganisms, and the percentage of the self-source microbial material amount in the total amount of the material in the fermentation tank was 1.1±0.1% (w / w).

[0118] (3) Preparation of self-source microbial fermentation liquid

[0119] According to the weight percentage, the medium raw material composition was as follows:

[0120] Self-source microorganism: 28% (w / w)

[0121] Corn starch gelatinized liquid: 66% (w / w)

[0122] Lactobacillus reuteri fermentation liquid: 6% (w / w)

[0123] The concentration of the corn starch gelatinized liquid is between 5.3% (w / w).

[0124] Then, the fermentation end point protease activity is determined after the fermentation in the fermentation tank at 37±1℃ for 19 hours.

[0125] The value should reach above 700 U / mL, and the sum of the acid protease and neutral protease activities is not less than 650 U / mL.

[0126] The prepared self-source microorganism fermentation liquid is returned and poured into the soy sauce mash.

[0127] Step three: thereafter, the process of step two is repeated at the fermentation time of 30 days, 50 days and 75 days, respectively, so that the frequency of repeating the process of step two is totally 4 times, and the final soy sauce mash is fermented to maturity after 90±3 days of fermentation. The liquid material is discharged to prepare high-quality soy sauce.

[0128] Comparative example 1:

[0129] The fermentation efficiency of example 1 and the conventional production is compared, and the protease activity parameters of the fermentation process and the amino acid nitrogen content of the collected soy sauce at the fermentation end point are compared, and the specific data are shown in Table 1.

[0130] Table 1 Comparison of protease activity of the fermentation process of example 1 and the conventional production

[0131]

[0132]

[0133] From the data in Table 1, it can be seen that the self-source microorganism fermentation liquid is added at the fermentation time of 10 days, 25 days and 45 days in example 1, which has a relatively obvious effect on improving the protease activity in the fermentation tank, especially for the neutral protease and acid protease activities which play a key role in the soy sauce fermentation, which provides higher catalytic activity and fermentation effect for the hydrolysis of proteins to amino acids in the soy sauce fermentation process, can obviously improve the efficiency of the tank fermentation, improve the utilization rate of proteins, and make the amino acid nitrogen content of the obtained soy sauce increase obviously. Compared with the amino acid nitrogen content of the soy sauce obtained at the fermentation end point of example 1 and the conventional production, it can be seen that the amino acid nitrogen content of example 1 increases by more than 20%.

[0134] Comparative example 2:

[0135] The fermentation performance of Example 3 and the conventional production were compared, and the protease activity parameters of the fermentation processes and the amino acid nitrogen content of the collected soy sauce at the end of fermentation were compared, and the specific data are shown in Table 2.

[0136] Table 2 Comparison of protease activity of fermentation processes of Example 3 and conventional production

[0137]

[0138] As can be seen from the data in Table 2, in Example 3, the self-source microbial fermentation liquor was added at 15 days, 30 days / 50 days and 75 days of fermentation, respectively, and the results were similar to those of Example 1. The protease activity in the fermentation tank was significantly improved, among which the activities of neutral protease and acid protease, which played a key role in soy sauce fermentation, were greatly improved, and the activity of neutral protease was particularly improved. This provided stronger catalytic activity and fermentation effect for the hydrolysis of proteins to amino acids in the soy sauce fermentation process, could significantly improve the efficiency of tank fermentation, improve the utilization rate of proteins, and significantly improve the amino acid nitrogen content of the obtained soy sauce. Compared with the amino acid nitrogen content of the soy sauce obtained at the end of fermentation of Example 3 and conventional production, the amino acid nitrogen content of Example 3 was increased by nearly 25%.

[0139] As described above, the present application realizes the promotion of soy sauce fermentation by self-source microorganisms in the fermentation tank, improves the utilization rate of proteins and the conversion rate of amino acids, reduces precipitation, and improves the flavor quality of soy sauce products by repeatedly returning the fermentation culture liquor to the fermentation tank after the fermentation of the self-source microorganisms outside the fermentation tank and the synergistic fermentation of the Lactobacillus reuteri fermentation liquor. The self-source microbial fermentation culture can be prepared in a short time to produce a fermentation liquor with high activity of protease, which is returned to the fermentation tank for utilization, thereby improving the degree and efficiency of protein hydrolysis in the fermentation tank, and further improving the utilization rate and conversion rate of protein resources. The Lactobacillus reuteri utilizes the mash fermentation liquor in the fermentation tank as a basic nutrient source and ferments with an appropriate amount of white granulated sugar to produce a fermentation liquor with the function of inhibiting Escherichia coli, which can resist the contamination of Escherichia coli in the fermentation process of self-source microorganisms outside the fermentation tank, ensure the safety of the returned fermentation liquor, and further improve the production performance of the soy sauce tank fermentation technology.

[0140] The embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods and shall be included in the protection scope of the present application.

Claims

1. A method for improving the efficiency of soy sauce tank fermentation, based on the fermentation process of mature soy sauce koji material in a fermentation tank, characterized by, It comprises the following steps: Step one: mature soy sauce koji material is mixed with 19%±1% w / w salt water in a fermentation tank at a weight ratio of 1:2.2 to form a diluted mash, and fermentation is started; Step two: after the diluted mash is fermented, the surface layer of the mash is taken as a source of microorganisms, mixed with corn starch paste and Lactobacillus reuteri fermentation liquid in a fermentation tank, and then fermented to obtain a self-source microbial fermentation liquid; the self-source microbial fermentation liquid obtained is returned and poured into the mash; Step three: thereafter, the process of step two is repeated; the frequency of repeating the process of step two is three to four times in total, and the mash is finally fermented to maturity; the liquid part of the material is discharged to produce high-quality soy sauce; The Lactobacillus reuteri fermentation liquid of step two is prepared by adding white granulated sugar and water to the mash fermentation liquid and inoculating Lactobacillus reuteri; according to the weight ratio, the fermentation medium is composed of: Mash fermentation liquid: 34% w / w; White granulated sugar: 6% w / w; Water: 60% w / w; Lactobacillus reuteri: inoculum of 10 6 CFU / mL; The fermentation process conditions are as follows: after the mash fermentation liquid, white granulated sugar and water are mixed and dissolved, heating to 93±2℃ for 20 minutes, then cooling to 37±1℃, inoculating Lactobacillus reuteri, and incubating at 37±1℃ for 12 hours, then boiling for 5 minutes for sterilization treatment, the Lactobacillus reuteri fermentation liquid can be obtained; The pH value of the prepared fermentation liquid is 4.3±0.2, the total acid content is 1.6±0.3 g / 100mL, and it has an inhibitory effect on Escherichia coli; the inhibition zone test method is used for inspection, and the diameter of the inhibition zone is required to be greater than 12 mm; The self-source microorganism in step two refers to the microorganism cultivated in the 1cm-thick material on the surface layer of the mash in the fermentation tank; The microorganism is a microbial system from the soy sauce koji material and the environment of the fermentation tank, which survives under high-salt conditions in the mash and is obtained through high-salt screening during the mash fermentation process; therefore, the 1cm-thick material on the surface layer of the mash is called a self-source microorganism, and the percentage of the self-source microorganism material in the total amount of the material in the fermentation tank is 1.1±0.1% w / w.

2. The method of improving the efficiency of a soy sauce tank fermentation according to claim 1, wherein, The self-source microbial fermentation liquid of step two is composed of the following raw materials according to the weight percentage: Self-source microorganism: 18%-32% w / w; Corn starch paste: 62%-76% w / w; Lactobacillus reuteri fermentation liquid: 6% w / w; The concentration of the corn starch paste is 4.6%-5.6% w / w; Then, the fermentation is carried out in a fermentation tank at 37±1℃ for 16-28 hours, and the protease activity at the end of fermentation reaches more than 700 U / mL, and the sum of the activities of acid protease and neutral protease is not less than 650 U / mL.

3. The method of improving the efficiency of a soy sauce tank fermentation according to claim 1, wherein, The frequency of repeating the process of step two and the fermentation time of step three are as follows: the production time is from mid-April to mid-October each year, the frequency is three times in total, and the fermentation time is 70±3 days; the frequency of the remaining production time is four times in total, and the fermentation time is 90±3 days.

4. High-quality soy sauce prepared by the method of any one of claims 1-3.

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