Efficient fermentation process for reducing soy sauce koji making amount and increasing amino acid content of soy sauce mash

Abstract

The invention belongs to the technical field of food fermentation and brewing, and particularly relates to an efficient fermentation process for reducing soy sauce koji making amount and increasing soy sauce mash amino acid content. The process comprises the following steps: (1) roasting wheat at ultrahigh temperature for a short time; 2) cooking the raw materials; (3) making koji; and (4) supplementing materials and fermenting. According to the process, the aspergillus oryzae strain PCSM001 is used for preparing the high-enzyme-activity soy sauce koji to provide sufficient endogenous biological enzyme to directly hydrolyze high-protein cooked materials which are not subjected to koji making, so that the koji making workload of part of raw materials is reduced, and the koji making energy consumption is reduced; the substrate consumption of microbial growth metabolism in the starter propagation process is also reduced, and the conversion rate of raw materials is improved. In addition, by supplementing a large amount of high-protein clinker, the content of amino acid in the fermented soy sauce mash is greatly increased, and the product quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of food fermentation and brewing, and specifically relates to an efficient fermentation process for reducing the amount of soy sauce koji and improving the amino acid content of soy sauce mash. Background Art

[0002] Soy sauce is a traditional fermented liquid condiment in my country. It is mainly made from soybeans or soybean meal, wheat flour, etc., and is processed through processes such as koji making, fermentation, pressing, and refining. Among them, koji making is the key link in soy sauce brewing, which directly determines the quality of the product and the utilization rate of raw materials. Soy sauce koji making uses Aspergillus oryzae to grow on the surface of koji materials to enrich various biological enzymes and provide sufficient enzymes for the subsequent fermentation process. However, unlike fermented foods such as liquor and vinegar that use koji as a fermentation agent, soy sauce brewing uses koji as the main raw material. For example, in the high-salt dilute fermentation process, the finished koji and brine are usually mixed and fermented at a mass ratio of 1: (1.8-2.5), which leads to a large amount of koji making work in soy sauce processing. However, the koji making process is complicated, with poor controllability and high energy consumption, especially energy consumption accounts for about a quarter of the entire soy sauce production process. Therefore, reducing the workload of koji making is of great significance to improving the efficiency of soy sauce processing.

[0003] In addition, soy sauce is famous for its umami taste, which mainly comes from umami substances such as amino acids, nucleotides, and umami peptides, especially amino acids, which contribute the most to the umami taste of soy sauce. In order to meet consumers' demand for high-umami soy sauce, the main method of increasing the amino acid content of products in the existing technology is to add umami substances such as monosodium glutamate. However, with the improvement of living standards, people are paying more and more attention to healthy diet. The additional addition of these umami agents will not only leave a bad impression on consumers, but also increase production costs, ultimately affecting the competitiveness of the products.

[0004] It can be seen that how to improve the existing technology and provide a method that can reduce the workload of koji making, simplify the process, reduce costs, while increasing the amino acid content of fermented sauce and mash and enhancing the umami taste of the product is a technical problem that needs to be urgently solved in this field. Summary of the invention

[0005] The object of the present invention is to provide an Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) in view of the above technical problems. The Aspergillus oryzae strain PCSM001 has strong protease production ability and a complete enzyme system.

[0006] Another object of the present invention is to provide the use of the above-mentioned Aspergillus oryzae strain in preparing high enzyme activity soy sauce koji or in soy sauce brewing. Using Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) to make high enzyme activity soy sauce koji, so as to realize the additional addition of high protein raw materials for fermentation in the subsequent fermentation process, effectively reduce the workload of soy sauce koji making, and increase the amino acid content in the mash, and enhance the umami taste of soy sauce.

[0007] In order to achieve the above-mentioned object of the invention, the specific technical solution of the present invention is:

[0008] The invention provides an Aspergillus oryzae strain PCSM001 (Aspergillus oryzae).

[0009] The Aspergillus oryzae strain was deposited in the Guangdong Provincial Microbial Culture Collection Center on June 5, 2017. Its Latin name is Aspergillus oryzae, and its deposit number is GDMCC No: 60199. The address of the depository unit is 5th Floor, Building 59, No. 100, Xianlie Middle Road, Guangzhou. This strain is an existing strain, but when it is further developed and utilized, it is used to prepare soy sauce mash. It is found that it has the characteristics of strong protease production ability and complete enzyme system, so it is used in the application of high enzyme activity soy sauce koji or the production process of soy sauce mash with excellent performance.

[0010] In order to better prepare soy sauce mash, the present invention also provides an efficient fermentation process for reducing the workload of soy sauce koji making and improving the amino acid content of mash. The above-mentioned Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) is used in the method, and the specific preparation method comprises the following steps:

[0011] (1) Wheat roasting: After wheat is screened and impurities are removed, it is moistened to increase the moisture content of wheat; then the water is drained and immediately sent to a wheat roasting machine for ultra-high temperature and short-time roasting. The ultra-high temperature and short-time roasting causes a large amount of water inside the wheat to vaporize too quickly, thereby completely destroying the cell tissue structure, improving the protein digestibility and starch gelatinization of the roasted wheat, and then increasing the decomposition rate and conversion rate of protein and starch in the subsequent fermentation process. Finally, the wheat is immediately sent to an air cooler after being baked, cooled to below 40°C, and then crushed to obtain roasted wheat flour.

[0012] Further preferably, in step (1), the wheat is moistened by soaking in hot water at 50°C to 70°C for 10 to 20 minutes, and the moisture content of the wheat is required to reach 25% to 35%;

[0013] The high temperature short time roasting condition is 250~300℃ ultra-high temperature roasting for 10~20min;

[0014] The roasted wheat is crushed into 4 to 6 pieces, and 30-mesh powder accounts for 30% to 40%.

[0015] (2) Raw material cooking: After the soybean meal is moistened with water, it is steamed at a temperature of 130-135°C and a pressure of 0.25-0.30 MPa for 3-5 min, and then immediately air-cooled to 35-40°C to obtain soybean meal clinker.

[0016] Further preferably, the moistening conditions in step (2) are: the moistening weight is 110% to 130% of the weight of the soybean meal, and the moistening temperature is 80 to 90°C.

[0017] (3) Preparation of high enzyme activity soy sauce koji: The fried wheat flour and soybean meal prepared in step (2) and step (3) are mixed in proportion, and inoculated with a starter of Aspergillus oryzae strain PCSM001. Finally, the inoculated mixed koji material is conveyed to a disc koji making machine for koji making, and cultured for 40 to 48 hours to obtain a high enzyme activity soy sauce koji.

[0018] Further preferably, in step (3), the soybean meal cooked material and the fried wheat flour are mixed in a ratio of soybean meal raw material mass to fried wheat flour mass = 8: (2-2.5);

[0019] The inoculation amount of Aspergillus oryzae PCSM001 starter is 0.03% to 0.1% (based on the dry weight of the raw material);

[0020] The specific conditions for disc koji making are: material layer thickness of 25 to 40 cm, koji making humidity of ≥90% rh, koji making temperature of 28 to 33 °C, koji turning once within 12 hours during koji making, and the second turning should be done 4 to 6 hours after the first turning.

[0021] Preparation of Aspergillus oryzae PCSM001 starter: The Aspergillus oryzae PCSM001 is subjected to multi-stage seed expansion culture in a bran medium (conventional method), and spores are separated or not to obtain the Aspergillus oryzae PCSM001 starter.

[0022] The leavening agent can be bran koji (containing live bacteria of Aspergillus species PCSM001) or spore powder of Aspergillus oryzae strain PCSM001. The preparation of these two products is the same as the prior art.

[0023] (4) Soy sauce feed fermentation: The high enzyme activity soy sauce koji prepared in step (3) is mixed with low-temperature brine at 5-10° C. in proportion, and high-protein cooked material that has not been made into koji after steaming is added before fermentation, and the mixture is fermented in a tank.

[0024] The abundant endogenous biological enzymes in the high-enzyme activity soy sauce koji are used to directly hydrolyze the high-protein clinker that has not been koji-made, thereby reducing the workload of koji-making for some raw materials and reducing the energy consumption of koji-making; at the same time, the amino acid content in the fermented sauce mash is greatly increased, thereby improving product quality.

[0025] Further preferably, in step (4), the high enzyme activity soy sauce koji and the low temperature brine are mixed in a mass ratio of 1:(1.5-3);

[0026] The salt content concentration of the low-temperature brine is 20-25 g / 100 mL, and the salt content concentration in the final sauce mash system is required to be controlled to reach 16-18 g / 100 mL.

[0027] The high-protein clinker is a clinker obtained by steaming one or more of the protein raw materials according to step (2) and rapidly cooling the raw materials, or a mixed clinker obtained by mixing one or more of the protein raw materials with fried wheat flour in a mass ratio of 5:(1-5), steaming the raw materials according to step (2), and rapidly cooling the raw materials.

[0028] Protein raw materials include but are not limited to soybean meal, soybeans, defatted soybeans, etc.

[0029] The added amount of the high-protein clinker is 10% to 30% of the total weight of the koji-making raw materials.

[0030] The soy sauce supplementary fermentation conditions are: fermentation at 15-20°C for 30 days, stirring once a day during this period; then the temperature is raised to 28-30°C for fermentation for 4-6 months, stirring once every 10-15 days during this period.

[0031] Another object of the present invention is to protect the mash obtained by the above-mentioned process or combination of process steps, which is the mash for making soy sauce.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The Aspergillus oryzae strain PCSM001 provided by the present invention is found to be able to produce high levels of protease and has a balanced enzyme system; further using the Aspergillus oryzae strain PCSM001 in the soy sauce brewing process can improve the enzyme activity of the soy sauce koji, thereby providing sufficient and balanced endogenous biological enzymes for the fed-batch fermentation of soy sauce, reducing the workload of koji making, reducing the energy loss of koji making, and at the same time improving the amino acid content of the fermented soy sauce mash.

[0034] (ii) The present invention adopts a fed-batch fermentation process, and utilizes sufficient endogenous biological enzymes in high-enzyme activity soy sauce koji to directly hydrolyze the un-kojied high-protein clinker, thereby realizing the simultaneous hydrolysis and fermentation, with a simple process and convenient operation. At the same time, there is no need to add an additional raw material hydrolysis process, nor is there any need to add biological enzyme preparations, which greatly reduces the production cost and the convenience of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The colony morphology of Aspergillus oryzae strain PCSM001 in Example 1;

[0036] Figure 2 The bacterial morphology of Aspergillus oryzae strain PCSM001 under a scanning electron microscope in Example 1;

[0037] Figure 3 The figure shows the changes in the physical and chemical indicators of the sauce mash during the fermentation process using different processes in Example 1. DETAILED DESCRIPTION

[0038] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0039] Any feature disclosed in this specification (including claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0040] The features and properties of the present invention are further described in detail below in conjunction with the examples. In the present application, % without special descriptions all represent mass percentage, i.e. wt%.

[0041] Embodiment 1:

[0042] Evaluation of enzyme production ability of Aspergillus oryzae strain PCSM001

[0043] The preserved Aspergillus oryzae strain PCSM001 is activated (the activation method is the existing technology), and then the activated Aspergillus oryzae strain PCSM001 is inoculated into a bran culture medium and cultured at a temperature of 30°C for 120 hours. During the culture period, the agglomerated bran culture medium is regularly shaken off to obtain bran koji of Aspergillus oryzae strain PCSM001.

[0044] The existing method was then used to determine the activities of acid protease, neutral protease, aminopeptidase, carboxypeptidase and amylase in the bran of Aspergillus oryzae strain PCSM001, and Aspergillus oryzae Shanghai Brewing 3.042 was used as a control. The results are shown in Table 1.

[0045] Table 1 Enzyme production characteristics of Aspergillus oryzae strain PCSM001

[0046] project Aspergillus oryzae PCSM001 Aspergillus oryzae Shanghai Brewing 3.042 Acid protease (U / g) 1125 689 Neutral protease (U / g) 1916 1055 Aminopeptidase (U / g) 2646 1342 Carboxypeptidase (U / g) 1567 794 Amylase (U / g) 2889 1770

[0047] As shown in Table 1, compared with Aspergillus oryzae Huniang 3.042, the activities of acidic protease, neutral protease, aminopeptidase, carboxypeptidase and amylase of Aspergillus oryzae strain PCSM001 were increased by more than 60%, and the activities of some enzymes were even about 1 times higher. This shows that Aspergillus oryzae strain PCSM001 has strong enzyme production ability and balanced enzyme production system, especially outstanding protease production ability.

[0048] Embodiment 2:

[0049] An efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash, comprising the following steps:

[0050] (1) Preparation of starter: The Aspergillus oryzae strain PCSM001 is subjected to multi-stage seed expansion culture in a bran medium to obtain PCSM001 bran koji, i.e., the Aspergillus oryzae strain PCSM001 starter.

[0051] (2) Wheat roasting

[0052] After screening and removing impurities, the wheat is soaked in 60℃ hot water for 15 minutes, and the water content of the wheat is required to reach 30%. The wheat is immediately filtered after soaking, and then put into the wheat roasting machine for high temperature roasting at 280℃ for 15 minutes. After that, the wheat is immediately put into the air cooling machine to cool to below 40℃, and finally crushed to obtain fried wheat flour.

[0053] More preferably, the roasted wheat is crushed into 4 to 6 petals, and 30-mesh powder accounts for 30% to 40%.

[0054] (3) Raw material cooking

[0055] After being moistened with water, the soybean meal is steamed at a temperature of 135°C and a pressure of 0.30 MPa for 3 minutes, and then immediately air-cooled to 35-40°C to obtain soybean meal clinker.

[0056] The specific watering parameters are: the watering weight is 120% of the soybean meal weight, and the watering temperature is 85°C.

[0057] (4) Preparation of high enzyme activity soy sauce koji

[0058] The fried wheat flour and soybean meal cooked material prepared in step (2) and step (3) are mixed in a mass ratio of 8:2 (based on the mass of the soybean meal raw material and the fried wheat flour, respectively) to obtain a mixed koji material; and 0.1% (based on the dry weight of the raw materials) of Aspergillus oryzae strain PCSM001 starter is inoculated, and finally the inoculated mixed koji material is conveyed to a disc koji making machine and cultured for 45 hours to obtain a soy sauce koji, i.e., a soy sauce koji with high enzyme activity.

[0059] The specific conditions for disc koji making are: material layer thickness of 30 cm, koji making humidity of ≥90% rh, koji making temperature of 28-33°C, koji turning once within 12 hours during koji making, and the second turning is carried out 6 hours after the first turning.

[0060] (5) Soy sauce feed fermentation

[0061] The high enzyme activity soy sauce koji prepared in step (4) is mixed with low-temperature brine at 10°C in a mass ratio of 1:2.5, and high-protein cooked material that has not been made into koji after cooking is added before fermentation. The mixture is put into a tank and fermented at 15-20°C for 30 days, during which time the mixture is stirred once a day. Thereafter, the temperature is increased to 28-30°C and fermented for 5 months, during which time the mixture is stirred once every 10 days, to obtain soy sauce mash.

[0062] The salt content concentration of the low-temperature brine is 22g / 100mL, and it is required to control the salt content concentration in the final sauce mash system to reach 17g / 100mL.

[0063] The high-protein clinker is obtained by steaming soybean meal according to step (3) and rapidly cooling the raw material to obtain a mixed clinker.

[0064] The added amount of the mixed clinker is 20% of the total weight of the koji-making raw materials.

[0065] Embodiment 3:

[0066] An efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash, comprising the following steps:

[0067] (1) Preparation of starter: The Aspergillus oryzae strain PCSM001 is subjected to multi-stage seed expansion culture in a bran culture medium to obtain PCSM001 bran koji (prior art), i.e., the Aspergillus oryzae strain PCSM001 starter.

[0068] (2) Wheat roasting

[0069] After screening and removing impurities, the wheat is soaked in 60℃ hot water for 15 minutes, and the water content of the wheat is required to reach 30%. The wheat is immediately filtered after soaking, and then put into the wheat roasting machine for high temperature roasting at 280℃ for 15 minutes. After that, the wheat is immediately put into the air cooling machine to cool to below 40℃, and finally crushed to obtain fried wheat flour.

[0070] More preferably, the roasted wheat is crushed into 4 to 6 petals, and 30-mesh powder accounts for 30% to 40%.

[0071] (3) Raw material cooking

[0072] After being moistened with water, the soybean meal is steamed at a temperature of 135°C and a pressure of 0.30 MPa for 3 minutes, and then immediately air-cooled to 35-40°C to obtain soybean meal clinker.

[0073] The specific watering parameters are: the watering weight is 120% of the soybean meal weight, and the watering temperature is 85°C.

[0074] (4) Preparation of high enzyme activity soy sauce koji

[0075] The fried wheat flour and soybean meal prepared in step (2) and step (3) are mixed in a mass ratio of 8:2.5 (based on the mass of the soybean meal raw material and the fried wheat flour, respectively), and 0.1% (based on the dry weight of the raw materials) of Aspergillus oryzae strain PCSM001 starter is inoculated, and finally the inoculated mixed koji material is conveyed to a disc koji making machine and cultured for 45 hours to obtain soy sauce koji.

[0076] The specific conditions for disc koji making are: material layer thickness of 30 cm, koji making humidity of ≥90% rh, koji making temperature of 28-33°C, koji turning once within 12 hours during koji making, and the second turning is carried out 6 hours after the first turning.

[0077] (5) Soy sauce feed fermentation

[0078] The high enzyme activity soy sauce koji prepared in step (4) is mixed with low-temperature brine at 10°C in a mass ratio of 1:2.5, and high-protein cooked material that has not been made into koji after cooking is added before fermentation. The mixture is put into a tank and fermented at 15-20°C for 30 days, during which time the mixture is stirred once a day. Thereafter, the temperature is increased to 28-30°C and fermented for 5 months, during which time the mixture is stirred once every 15 days, to obtain soy sauce mash.

[0079] Further preferably, the salt content concentration of the low-temperature brine is 22 g / 100 mL, and the salt content concentration in the final sauce mash system is required to be controlled to reach 17 g / 100 mL.

[0080] Further preferably, the high-protein mixed clinker is prepared by mixing soybean meal and fried wheat flour in a mass ratio of 5:5, steaming the raw materials according to step (2), and rapidly cooling the mixed clinker.

[0081] Further preferably, the amount of the mixed clinker added is 30% of the total weight of the koji-making raw materials.

[0082] Comparative Example 1:

[0083] The method for preparing soy sauce mash is the same as that in Example 2, except that the wheat roasting step is different:

[0084] The specific steps of step (2) wheat roasting are:

[0085] After screening and removing impurities, the wheat is directly put into the wheat roasting machine without soaking in hot water and roasted at 160℃ for 30 minutes. Then the wheat is immediately put into the air cooler to be cooled to below 40℃ and finally crushed to obtain fried wheat flour.

[0086] The remaining steps are the same as those in Example 2, and finally the soy sauce mash is obtained.

[0087] The fried wheat flour and soy sauce mash prepared in Example 2 and the fried wheat flour and soy sauce mash prepared in Comparative Example 1 were tested and analyzed, and the protein digestibility, starch gelatinization, and amino acid nitrogen and reducing sugar content of the fermented mash of the fried wheat flour prepared by the two technologies were compared. The results are shown in Table 2 below.

[0088] Table 2 Effect of different wheat roasting processes

[0089]

[0090] As can be seen from Table 2, compared with the common wheat roasting process (Comparative Example 1), the degree of protein and starch denaturation in the ultra-high temperature short-time roasting (Example 2) wheat is significantly improved, wherein the protein digestibility is increased by 45.2%; the starch gelatinization degree is increased by 44.9%, which is mainly due to the ultra-high temperature short-time roasting technology to increase the moisture content and roasting temperature of the material, so that the water can be quickly vaporized under high temperature conditions, thereby improving the protein denaturation and starch gelatinization degree. In addition, the amino acid nitrogen and reducing sugar content of the fermented sauce mash also increased significantly, indicating that the use of ultra-high temperature short-time roasting can further improve the conversion rate of the raw materials, thereby improving the quality of the fermented sauce mash. It should be noted that for this technical field, the increase in amino acid nitrogen in this application is very significant.

[0091] Comparative Example 2:

[0092] The method for preparing soy sauce mash is the same as that in Example 2, except that the Aspergillus oryzae strain PCSM001 is replaced with the Aspergillus oryzae Shanghai Niang 3.042 strain during the preparation of the starter. The specific steps of step (1) of preparing the starter are:

[0093] The Aspergillus oryzae Shanghai Niang 3.042 strain is subjected to multi-stage seed expansion culture in a bran culture medium to obtain the Aspergillus oryzae Shanghai Niang 3.042 bran koji, namely the Aspergillus oryzae Shanghai Niang 3.042 strain starter.

[0094] The remaining steps are exactly the same as in Example 2, and finally soy sauce mash is obtained.

[0095] Comparative Example 3:

[0096] The preparation method of soy sauce mash is the same as that of Example 2, except that during the soy sauce feeding fermentation, no high-protein cooked material that has not been made into koji after cooking is added before fermentation. The specific steps of step (5) of the soy sauce feeding fermentation are as follows:

[0097] The high enzyme activity soy sauce koji prepared in step (4) is mixed with low-temperature brine at 10°C in a mass ratio of 1:2.5, and fermented at 15-20°C for 30 days, stirring once a day during the fermentation; then the temperature is increased to 28-30°C and fermented for 5 months, stirring once every 15 days during the fermentation.

[0098] The salt content concentration of the low-temperature brine is 22g / 100mL, and it is required to control the salt content concentration in the final sauce mash system to reach 17g / 100mL.

[0099] The remaining steps are exactly the same as in Example 2, and finally soy sauce mash is obtained.

[0100] The quality of the soy sauce koji and soy sauce (fermented) mash prepared in the above Examples 2-3 and Comparative Examples 2-3 was tested and analyzed. The results are shown in Tables 3 and 4. Figure 3 shown.

[0101] Table 3 Comparative analysis of the quality of soy sauce koji and mash produced by different processes

[0102]

[0103] As can be seen from Table 3, the various biological enzyme activities of the finished koji in Example 2-3 are much higher than the enzyme activities of the finished koji in Comparative Example 2, which shows that the various enzyme activities of the soy sauce koji can be significantly improved by making koji with Aspergillus oryzae strain PCSM001. At the same time, the amino acid nitrogen content of the sauce mash in Example 2-3 is 1.12g / 100g and 1.06g / 100g, respectively, and the reducing sugar content is 6.3g / 100g and 7.4g / 100g, respectively, which is also much higher than the amino acid nitrogen content (0.77g / 100g) and reducing sugar content (5.7g / 100g) of the sauce mash in Comparative Example 2, indicating that the high enzyme activity soy sauce koji prepared by Aspergillus oryzae strain PCSM001 in Example 2-3 has enough endogenous biological enzymes to hydrolyze the added high-protein clinker to ensure the normal progress of subsequent fermentation. By comparing Example 2-3 with Comparative Example 3, it was found that the amino acid nitrogen content of the sauce mash in Example 2-3 was significantly higher than the amino acid nitrogen content of the sauce mash in Comparative Example 3 (0.87g / 100g), indicating that the content of amino acids and other substances in the sauce mash can be effectively improved through subsequent fed-batch fermentation.

[0104] Depend on Figure 3 It can be seen that the free amino acid content of the fermented sauce mash in Example 2-3 is significantly increased compared with that in Comparative Example 2-3, with the total amount of free amino acids increased by more than 20%, indicating that the technical scheme can effectively increase the amino acid content of the fermented sauce mash, laying the foundation for the preparation of high-quality soy sauce.

[0105] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0106] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. Application of an Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) in preparing high enzyme activity soy sauce koji, characterized in that: The deposit number of the Aspergillus oryzae strain PCSM001 is GDMCC No:60199.

2. The use according to claim 1, characterized in that: When preparing soy sauce koji, the high enzyme activity koji prepared by Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) is used to directly hydrolyze the high-protein clinker that has not been koji-made, thereby reducing the workload and energy consumption of koji-making; at the same time, the substrate consumption of microbial growth metabolism during koji-making is reduced, thereby improving the conversion rate of raw materials.

3. An efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash, characterized in that The following steps are involved: (1) Wheat roasting After screening and removing impurities, the wheat is soaked in hot water at 50℃ to 70℃ for 10 to 20 minutes to make the water content of the wheat reach 25wt% to 35wt%; the wheat after soaking is filtered and put into a wheat roasting machine for high-temperature short-time roasting; the wheat is immediately put into an air cooler after being taken out of the oven to be cooled to below 40℃, and then crushed to obtain fried wheat flour; The high temperature and short time roasting conditions are: high temperature roasting at 250-300℃ for 10-20min; (2) Raw material cooking After the soybean meal is moistened with water, it is steamed for 3 to 5 minutes at a temperature of 130 to 135°C and a pressure of 0.25 to 0.30 MPa, and then immediately air-cooled to 35 to 40°C to obtain soybean meal clinker; (3) Koji making The soybean meal cooked material and the fried wheat flour are mixed in proportion, and 0.03% to 0.1% of the Aspergillus oryzae strain PCSM001 (Aspergillus oryzae) starter is inoculated based on the dry weight of the raw materials to obtain a mixed koji material; the mixed koji material is conveyed to a disc koji making machine for culturing for 40 to 48 hours to obtain a soy sauce koji; (4) Soy sauce feed fermentation The prepared soy sauce koji is mixed with low-temperature brine at a mass ratio of 1:1.5-3, and the high-protein cooked material without koji is directly added to the fermentation tank before fermentation. The product is fermented at 15-20°C for 30 days, stirring once a day during the fermentation. The temperature is then raised to 28-30°C for fermentation for 4-6 months, stirring once every 10-15 days during the fermentation.

4. The efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash according to claim 3, characterized in that: In step (1), the fried wheat is crushed into 4 to 6 petals, and the 30-mesh powder accounts for 30% to 40% of the total mass of the fried wheat flour.

5. A high-efficiency fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash as claimed in claim 3 or 4, characterized in that: In step (2), the specific watering parameters are: the watering weight is 110% to 130% of the soybean meal weight, and the watering temperature is 80 to 90°C.

6. The efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash according to claim 5, characterized in that: In step (3), the mass ratio of soybean meal to fried wheat flour is 8:2-2.5; the specific conditions of the disc koji making are: the material layer thickness is 25-40 cm, the koji making humidity is ≥90% rh, the koji making temperature is 28-33°C, the koji is turned once within 12 hours during the koji making, and the second koji is turned 4-6 hours after the first koji.

7. A high-efficiency fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash as claimed in claim 3 or 6, characterized in that: In step (4), the salt content concentration of the low-temperature brine is 20-25 g / 100 mL, and the salt content concentration in the final sauce mash system is required to be controlled to reach 16-18 g / 100 mL.

8. The efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash according to claim 7, characterized in that: In step (4), the high-protein clinker is any one or more of soybean meal, soybeans, and defatted soybeans, which are steamed according to step (2) and rapidly cooled to obtain the high-protein clinker; or any one or more of soybean meal, soybeans, and defatted soybeans are mixed with fried wheat flour in a mass ratio of 5:1 to 5, which are steamed according to step (2) and rapidly cooled to obtain the high-protein clinker.

9. The efficient fermentation process for reducing the amount of soy sauce koji and increasing the amino acid content of soy sauce mash according to claim 8, characterized in that: The addition amount of the high-protein clinker is 10% to 30% of the total weight of the koji-making raw materials.

10. The mash for making soy sauce obtained by the process as described in any one of claims 3, 4, 6, 8 and 9.

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