Granules and soy sauce having a function of promoting koji-making, and methods for producing the same and a method for producing koji for soy sauce

Abstract

The present application relates to the technical field of seasoning brewing, and discloses a particle with a function of promoting koji making, soy sauce, and a preparation method of the particle and the soy sauce and a preparation method of koji for soy sauce. The preparation method of the particle comprises the following steps: (1) dry steaming a protein raw material for koji making; and (2) first mixing the dry steamed protein raw material for koji making with a plant source bacteriostatic component and granulating. The koji for soy sauce prepared by using the particle provided by the present application has a significantly higher enzyme activity, can effectively resist microbial contamination during the koji making process of the soy sauce, and can avoid burning koji. The content of total nitrogen and amino acid nitrogen in the soy sauce prepared in this way is higher, and the quality of the soy sauce is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of condiment brewing, in particular to a kind of granules with promoting koji making function and soy sauce and their preparation method and the preparation method of koji for soy sauce. BACKGROUND

[0002] In recent years, the price of soy sauce and soybean meal increases year by year, and the cost pressure of raw materials increases, so it is imperative to develop other protein raw material resources. Peanut meal, as an agricultural byproduct, is mostly used in the production of animal feed, and less used in the field of soy sauce and related compound sauces. The development of peanut meal soy sauce can realize the recycling of economic byproducts, which is also the fundamental of enterprise development. Moreover, peanut meal soy sauce has a unique flavor, a sweet and fresh aroma, and meets the needs of contemporary consumers, with a broad market application prospect.

[0003] However, the peanut meal after oil extraction has small particles, and if it is directly used for soy sauce brewing, the air flow during koji making process is small, which is easy to burn koji. Therefore, it is necessary to develop a method that can avoid burning koji and obtain soy sauce with good quality. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned problems existing in the prior art, and to provide a kind of granules with promoting koji making function and soy sauce and their preparation method and the preparation method of koji for soy sauce. Compared with traditional koji, the koji for soy sauce prepared by the granules provided by the present application has higher enzyme activity, and can effectively resist microbial contamination and avoid burning koji during soy sauce koji making process. The total nitrogen content and amino acid nitrogen content in the soy sauce prepared in this way are higher, and the quality of the soy sauce is better.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a preparation method of granules with promoting koji making function, which comprises:

[0006] (1) dry steaming the protein raw material for koji making;

[0007] (2) first mixing the dry steamed protein raw material for koji making and plant source bacteriostatic ingredients, and granulating the first mixing product.

[0008] The second aspect of the present application provides granules with promoting koji making function prepared by the method as described above.

[0009] The third aspect of the present application provides a preparation method of koji for soy sauce, which comprises: second mixing starch raw material, fermentation agent, seed koji and granules with promoting koji making function as described in the second aspect, and stacking and fermenting the second mixed material to obtain koji.

[0010] The fourth aspect of the present application provides a method for preparing soy sauce, which comprises: carrying out third mixing and fermentation of brine and koji for soy sauce prepared by the method of the third aspect.

[0011] The fifth aspect of the present application provides soy sauce prepared by the method of the fourth aspect.

[0012] When the koji for soy sauce prepared by the granules of the present application is used, microbial contamination can be effectively resisted, the presence of the granules can ensure the dominant position of Aspergillus oryzae, and is conducive to the output and stability of enzyme system. Compared with traditional koji, the enzyme activity of the koji prepared by the method of the present application is significantly higher. The soy sauce prepared by using such koji has higher total nitrogen content and amino acid nitrogen content, and has better quality. In addition, when the koji is prepared by using the granules, burning koji can be avoided. DETAILED DESCRIPTION

[0013] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate points are not to be construed as being precise values by themselves, but are understood to be used in a generic sense to describe the approximate values. The endpoints of the ranges and the separate points can be combined with one another to create new ranges or points that are not expressly mentioned, and these new ranges or points are to be considered to be included within the scope of the present disclosure.

[0014] In a first aspect, the present application provides a method for preparing a granule having a function of promoting koji preparation, which comprises:

[0015] (1) dry steaming a protein raw material for koji preparation;

[0016] (2) first mixing the dry steamed protein raw material for koji preparation with a plant-derived antibacterial component, and granulating the first mixing product.

[0017] The inventors of the present application found in research that the granule prepared according to the above method, when used for preparing koji for soy sauce, can effectively resist microbial contamination, the presence of the granule can ensure the dominant position of Aspergillus oryzae, and is conducive to the output and stability of enzyme system, and the enzyme activity of the koji is significantly higher. Compared with traditional koji, the enzyme activity of the koji prepared by using the above granule is significantly higher. The soy sauce prepared by using such koji has higher total nitrogen content and amino acid nitrogen content, and has better quality.

[0018] According to the present application, preferably, the temperature of dry steaming is 115-126℃, the time is 0.3-0.5h, and the pressure is 0.08-0.15MPa. Through dry steaming, not only impurities and miscellaneous bacteria in the protein raw material for koji preparation can be removed, but also the protein can be denatured moderately, so as to facilitate the decomposition of the protein for koji preparation.

[0019] According to the present application, preferably, the protein raw material for koji making is peanut meal and / or rapeseed meal, more preferably peanut meal. When peanut meal is used, not only the recycling of economic by-products can be realized, but also the peanut meal soy sauce has a unique flavor and broad market prospects. Generally, if peanut meal is directly used for the brewing of soy sauce, it is easy to cause burning koji, and the present inventors have further found that when peanut meal is used in the preparation of the granules having the function of promoting koji making, burning koji during koji making can also be avoided.

[0020] According to the present application, preferably, the mass content of the protein raw material for koji making in the first mixed product is 70-80wt%, relative to the total mass of the first mixed product.

[0021] According to the present application, preferably, the amount of the plant-derived bacteriostatic component is such that the mass content in the first mixed product is 10-15wt%. The present inventors have found in research that in the above case, the ability of the granules to resist microbial contamination when used for preparing koji for soy sauce can be further ensured.

[0022] According to the present application, preferably, in step (2), the first mixing further includes the operation of introducing a granulation aid into the mixing system.

[0023] Preferably, the granulation aid is flour. The granulation aid can make the components more easily bonded during granulation.

[0024] Preferably, the mass content of the granulation aid is 10-15wt%, relative to the total mass of the first mixed product.

[0025] According to the present application, preferably, the granulation is such that the particle size of the granules is 0.3-1.5cm, preferably 0.5-1cm (for example, it can be 0.5cm, 0.6cm, 0.7cm, 0.8cm, 0.9cm, 1cm, and any two of the above values and values within the range). It can be understood that the particle size of the obtained granules during granulation will not be completely uniform, and it can be within the above range; a drum granulation method can be used. When the above range is used, the koji material can be looser during koji making, and koji making is more likely to be successful.

[0026] According to the present application, preferably, the plant-derived bacteriostatic component is selected from at least one of onion extract, garlic extract and ginger extract.

[0027] Preferably, the preparation method of the plant-derived antibacterial component includes: mixing the raw material to be extracted with water and juicing it; wherein the mass ratio of the raw material to be extracted to water is 1:(1-1.5). For example, when the plant-derived antibacterial component is onion extract, the raw material to be extracted is onion; when the plant-derived antibacterial component is a mixture of onion extract and garlic extract, the raw materials to be extracted are onion and garlic. In operation, impurities can be removed from the raw material to be extracted first, then it can be washed, cut into pieces, and then water can be added for juicing. The mixture obtained after juicing is used as the plant-derived antibacterial component.

[0028] According to a particularly preferred embodiment of the present invention, the raw materials to be extracted include onions and garlic, with a mass ratio of onions to garlic of 3:(1-1.5). Thus, the plant-derived antibacterial components are preferably onion extract and garlic extract. This further ensures the dominant position of Aspergillus oryzae in the preparation of soy sauce koji.

[0029] Secondly, the present invention provides granules with koji-making-promoting function prepared by the method described above.

[0030] Thirdly, this invention provides a method for preparing koji for soy sauce, the method comprising: mixing starchy raw materials, a fermenting agent, a starter culture, and granules with koji-promoting function as described in the second aspect, and then pile-fermenting the mixture to obtain koji. It is understood that the fermenting agent added during the preparation of soy sauce koji is generally a microbial strain.

[0031] According to the present invention, preferably, the starchy raw material is roasted oatmeal. The oatmeal can be roasted at 100-150℃ for 3-5 minutes.

[0032] According to the present invention, preferably, the mass ratio of granules and starchy raw materials with the function of promoting koji making is (1-1.5):1.

[0033] According to the present invention, preferably, the fermenting agent is lactic acid bacteria, more preferably Lactobacillus plantarum. For example, it can be Lactobacillus plantarum CICC20346 purchased from the China Industrial Microbial Culture Collection Center.

[0034] According to the present invention, preferably, the amount of the fermenting agent is such that the initial content of the fermenting agent in the second mixed material is 1×10⁻⁶. 6 -1×10 7 cfu / g.

[0035] To ensure the starter culture is evenly distributed into the koji (fermentation starter), the cultured starter culture can be mixed with water first, and then added to the koji. The amount of water used can be 70-100 wt%, relative to the total mass of the starchy raw materials and the granules that promote koji production.

[0036] According to the present invention, preferably, the koji is an Aspergillus oryzae koji.

[0037] According to the present invention, preferably, the amount of Aspergillus oryzae inoculum is such that the initial content of Aspergillus oryzae in the second mixed material is 1×10⁻⁶. 8 -5×10 8 cfu / g. Aspergillus oryzae can be used in its spore form. Any Aspergillus oryzae starter culture available in the art for fermentation in the preparation of soy sauce is suitable for this invention, such as the starter culture culture from Shandong Hezhong Kangyuan Biotechnology Co., Ltd., catalog number Aspergillus oryzae Hu Niang 3.042.

[0038] The granules that promote koji-making can be mixed with starchy raw materials first, then mixed with the fermenting agent and water mixture as described above, and then inoculated with koji.

[0039] According to the present invention, preferably, the stacking fermentation method includes: after a first culture at 30-32°C for 12-15 hours, turning the koji, and then carrying out a second culture.

[0040] According to the present invention, preferably, the second cultivation method includes: culturing at 28-30℃ for 6-9 hours, performing a second turning of the koji, and then continuing cultivation for another 12-14 hours. Under the above conditions, a yellow-green koji can generally be obtained. The cultivation status of the koji can generally be judged by observing its condition. When the koji is yellow-green, has no obvious odor, and shows obvious spores rising, the cultivation effect can be considered good.

[0041] It is understandable that turning the koji refers to loosening the koji material, reducing ventilation resistance, and making the koji material temperature uniform, so as to facilitate the normal growth and reproduction of Aspergillus oryzae.

[0042] Fourthly, the present invention provides a method for preparing soy sauce, the method comprising: mixing brine and soy sauce prepared by the method described in the third aspect with koji and fermenting.

[0043] In soy sauce brewing, "chengqu" refers to the mixture of fermenting bacteria and raw materials obtained after the starter culture has grown and multiplied on the raw materials.

[0044] This invention does not impose any particular limitation on the specific fermentation method; it can be carried out according to methods commonly used in the field. The amount of brine used relative to 1 kg of koji (fermented starter) can be 2-3 L. The salt concentration in the brine can be 18-25 wt%. It is understood that in soy sauce fermentation, the salt in the brine refers to sodium chloride.

[0045] According to the present invention, preferably, the fermentation temperature is 28-32℃ and the time is 170-190 days. During the fermentation process, the mixture can be stirred daily. After fermentation, the fermented mash can be filtered, and the filtered liquid phase can be sterilized at 75-85℃ for 20-60 minutes. After standing and filtering to remove the precipitate, the finished soy sauce product is obtained.

[0046] Fifthly, the present invention provides soy sauce prepared by the method described in the fourth aspect.

[0047] According to the present invention, preferably, the total nitrogen content in the soy sauce is 1.57-1.68 g / 100 mL.

[0048] According to the present invention, preferably, the amino acid nitrogen content in the soy sauce is 1.25-1.33 g / 100 mL.

[0049] The present invention will be described in detail below through embodiments.

[0050] In the following examples, *Saccharomyces rouxii* was ATCC 28253; *Lactobacillus plantarum* was CICC 20346.

[0051] How to make fried oatmeal: Fry the oatmeal at 120℃ for 4 minutes.

[0052] The Aspergillus oryzae starter culture was purchased from Shandong Hezhong Kangyuan Biotechnology Co., Ltd., with product number Aspergillus oryzae Hu Niang 3.042 starter culture.

[0053] Granulation is performed using a drum granulation method.

[0054] Example 1

[0055] (1) Peanut meal was kept dry-steamed at 121℃ and 0.1MPa for 0.4h.

[0056] The juice is obtained by removing impurities from onions and garlic, washing and chopping them, adding water and juicing. The mass ratio of onions, garlic and water is 3:1.3:5.5. The material obtained after juicing is used as a plant-based antibacterial liquid.

[0057] The plant-derived antibacterial liquid, peanut meal, and flour were mixed to obtain a first mixed product. The amounts of each ingredient added were such that, relative to the total mass of the first mixed product, the peanut meal content was 75 wt%, the flour content was 12.5 wt%, and the plant-derived antibacterial component content was 12.5 wt%.

[0058] The first mixture was granulated to obtain particles with a diameter of 0.5-1 cm.

[0059] (2) The granules and fried oat flakes obtained in step (1) are mixed at a mass ratio of 1.3:1. A bacterial solution of *Lactobacillus plantarum* and water is prepared and mixed with the granules and oat flakes. Then, *Aspergillus oryzae* is inoculated to obtain the second mixed material. The amount of water used relative to the total mass of the granules and oat flakes is 85 wt%; the initial content of *Lactobacillus plantarum* is 5 × 10⁻⁶. 6 cfu / g, the initial content of Aspergillus oryzae was 3×10 8 cfu / g.

[0060] The third mixture was piled up for fermentation. After the first fermentation at 31℃ for 14 hours, the mixture was turned over and then spread out for further fermentation at 29℃. After another 7 hours, the mixture was turned over and spread out again, and fermentation continued for another 13 hours. A yellow-green Daqu (fermented starter culture) was obtained.

[0061] Example 2

[0062] (1) Peanut meal was kept dry-steamed at 126℃ and 0.15MPa for 0.3h.

[0063] The juice is obtained by removing impurities from onions and garlic, washing and chopping them, adding water and juicing. The mass ratio of onions, garlic and water is 3:1.5:6. The material obtained after juicing is used as a plant-based antibacterial liquid.

[0064] The plant-derived antibacterial liquid, peanut meal, and flour were mixed to obtain a first mixed product. The amounts added were such that, relative to the total mass of the first mixed product, the peanut meal content was 80 wt%, the flour content was 10 wt%, and the plant-derived antibacterial component content was 10 wt%.

[0065] The first mixture was granulated to obtain particles with a diameter of 0.5-1 cm.

[0066] (2) The granules and fried oatmeal obtained in step (1) are mixed at a mass ratio of 1:1. *Lactobacillus plantarum* and water are mixed to obtain a bacterial solution, which is then mixed with the granules and oatmeal. *Aspergillus oryzae* is then inoculated to obtain the second mixed material. The amount of water used relative to the total mass of the granules and oatmeal is 100 wt%; the initial content of *Lactobacillus plantarum* is 1 × 10⁻⁶. 6 cfu / g, of which the initial content of Aspergillus oryzae was 5×10 8 cfu / g.

[0067] The third mixture was piled up for fermentation. After the first 12 hours of cultivation at 32℃, the mixture was turned over and then cultivated flat at 30℃ for another 6 hours. The mixture was then turned over and spread flat again, and cultivated for another 12 hours. A yellow-green Daqu (fermented starter culture) was obtained.

[0068] Example 3

[0069] (1) Peanut meal was kept dry-steamed at 115℃ and 0.08MPa for 0.5h.

[0070] The juice is obtained by removing impurities from onions and garlic, washing and chopping them, adding water and juicing. The mass ratio of onions, garlic and water is 3:1:5. The material obtained after juicing is used as a plant-based antibacterial liquid.

[0071] The plant-derived antibacterial liquid, peanut meal, and flour were mixed to obtain a first mixed product. The amounts of each ingredient added were such that, relative to the total mass of the first mixed product, the peanut meal content was 70 wt%, the flour content was 15 wt%, and the plant-derived antibacterial component content was 15 wt%.

[0072] The first mixture was granulated to obtain particles with a diameter of 0.5-1 cm.

[0073] (2) The granules and fried oat flakes obtained in step (1) are mixed at a mass ratio of 1.5:1. *Lactobacillus plantarum* and water are mixed to obtain a bacterial solution, which is then mixed with the granules and oat flakes. *Aspergillus oryzae* is then inoculated to obtain the second mixed material. The amount of water used relative to the total mass of the granules and oat flakes is 70 wt%; the initial content of *Lactobacillus plantarum* is 1 × 10⁻⁶. 7 cfu / g, of which the initial content of Aspergillus oryzae was 1×10 8 cfu / g.

[0074] The third mixture was piled up for fermentation. After 15 hours of initial cultivation at 30℃, the mixture was turned over and then cultivated flat at 28℃ for another 9 hours. The mixture was then turned over and spread flat again, and cultivation continued for another 14 hours. A yellow-green Daqu (fermented starter culture) was obtained.

[0075] Example 4

[0076] The method is the same as in Example 1, except that the onion is replaced with ginger.

[0077] Example 5

[0078] The method is the same as in Example 1, except that the plant-derived antibacterial liquid contains 5 wt% of the total mass of the first mixture.

[0079] Example 6

[0080] The method is the same as in Example 1, except that the mass content of the granulation aid is 5 wt% relative to the total mass of the first mixture.

[0081] Example 7

[0082] The method is the same as in Example 1, except that in step (2), the mass ratio of the granules and fried oatmeal obtained in step (1) is 2:1.

[0083] Example 8

[0084] The method is the same as in Example 1, except that the amount of *Lactobacillus plantarum* used is adjusted so that the initial content of *Lactobacillus plantarum* in the second mixture is 1 × 10⁻⁶. 8 cfu / g.

[0085] Example 9

[0086] The method is the same as in Example 1, except that *Lactobacillus plantarum* is replaced with *Saccharomyces rouxii*.

[0087] Example 10

[0088] The method is the same as in Example 1, except that peanut meal is replaced with rapeseed meal.

[0089] Comparative Example 1

[0090] The method is the same as in Example 1, except that no plant-derived antibacterial solution is added.

[0091] Comparative Example 2

[0092] The method is the same as in Example 1, except that Lactobacillus plantarum is not added.

[0093] Comparative Example 3

[0094] (1) Mix peanut meal and water, wherein the mass of water is 100 wt% of the mass of peanut meal, and then heat the material at 121℃ and 0.1 MPa for 0.4 h.

[0095] (2) Add roasted oat flakes to the material prepared in step (1) so that the ratio of peanut meal to oat flakes is 1.3:1. After cooling to 38°C, add Aspergillus oryzae, wherein the initial content of Aspergillus oryzae is 1×10⁻⁶. 8 cfu / g.

[0096] The above materials were piled up for fermentation. After the first fermentation at 30℃ for 14 hours, the mixture was turned over and then spread out for further fermentation at 29℃. After another 7 hours, the mixture was turned over and spread out again, and fermentation continued for another 12 hours. A yellow-green Daqu (fermented starter culture) was obtained.

[0097] Comparative Example 4

[0098] The process is the same as in Example 1, except that the peanut meal is not granulated; instead, the plant-derived antibacterial liquid, peanut meal, and flour are mixed to obtain a first mixed product. When mixing with roasted oatmeal, the first mixed product and roasted oatmeal are mixed at a ratio of 1.3:1, and then the subsequent operations in Example 1 are performed.

[0099] Test Example 1

[0100] The results of observing the Daqu prepared in the above embodiments and comparative examples are shown in Table 1.

[0101] The protease activity of Daqu (a type of Chinese liquor) was determined using the formaldehyde method (SB / T 10317-1999), and the results are shown in Table 1.

[0102] Table 1

[0103]

[0104]

[0105] Furthermore, the bacterial community distribution of the cultures prepared in Examples 1-3 and Comparative Example 3 was determined as follows: Total genomic DNA was extracted using the Biospin Bacterial Genomic DNA Extraction Kit (purchased from Tianjin Jimmy Technology Co., Ltd.). PCR products were purified by 2% (w / v) agarose gel electrophoresis and recovered using the GeneJET DNA Gel Extraction Kit (purchased from Thermo Fisher Scientific). The purified PCR products were used to construct sequencing libraries, and high-throughput sequencing was performed using a Nova Seq 6000. The results are shown in Table 2.

[0106] Table 2

[0107]

[0108]

[0109] As can be seen from the above, the koji prepared using the method of the present invention has a good appearance. Using the granules provided by the present invention, microbial contamination can be effectively resisted when preparing koji for soy sauce. The presence of the granules ensures the dominant position of Aspergillus oryzae, which is beneficial to the production and stability of the enzyme system, and can produce koji with significantly higher protease activity. In particular, compared with koji prepared by traditional methods (such as Comparative Example 3), the koji prepared by the method of the present invention has significantly higher protease activity.

[0110] Furthermore, during the preparation of the koji, it was observed that none of the methods in Examples 1-10 resulted in koji burning, while Comparative Example 3 did exhibit koji burning. The method provided by this invention can also avoid koji burning during the preparation of soy sauce koji using peanut meal as raw material.

[0111] The solution of this invention can effectively resist microbial contamination during the soy sauce koji-making process. The soy sauce microbial community under particulate intervention is dominated by halophilic tetracocci and lactobacilli, while traditional fermentation may have the risk of microbial imbalance, with significantly higher levels of Stenotrophomonas maltophilia, Staphylococcus, and Proteus.

[0112] Test Example 2

[0113] Take the koji prepared in the above examples and comparative examples, and prepare soy sauce according to the following methods:

[0114] Mix the koji and a 20wt% sodium chloride solution, wherein the amount of brine used is 2.5L relative to 1kg of koji.

[0115] The materials are then fermented at 30℃ for 180 days, with daily stirring during this period. After fermentation, the mash is filtered, and the filtered liquid phase is sterilized at 80℃ for 40 minutes. After standing and filtering to remove sediment, the finished soy sauce is obtained.

[0116] For each of the above-mentioned soy sauce products, the total nitrogen and amino acid nitrogen content were determined according to the method in GB 18186-2000 Brewed Soy Sauce. The results are shown in Table 3.

[0117] Table 3

[0118] Total nitrogen content (g / 100 ml) Amino acid nitrogen content (g / 100 ml) Example 1 1.68 1.33 Example 2 1.57 1.25 Example 3 1.62 1.27 Example 4 1.47 1.09 Example 5 1.51 1.14 Example 6 1.39 1.02 Example 7 1.48 1.08 Example 8 1.50 1.17 Example 9 1.45 1.13 Example 10 1.44 1.09 Comparative Example 1 1.17 0.89 Comparative Example 2 1.31 0.93 Comparative Example 3 1.22 0.82 Comparative Example 4 1.26 0.98

[0119] It is evident that the soy sauce prepared using the method provided by this invention has a higher total nitrogen content and amino acid nitrogen content, resulting in better soy sauce quality.

[0120] Test Example 3

[0121] Furthermore, sensory evaluation was conducted on the various soy sauce products obtained in Test Example 2. The specific method was as follows: the participants consisted of 14 members (7 men and 7 women, aged 22 to 45 years) with sensory evaluation experience (having received at least one year of training). The participants were familiar with six flavor qualities (mellow aroma, malty aroma, soy sauce aroma, ester aroma, sweet aroma, and amine aroma). The results are shown in Table 4.

[0122] The scoring criteria for each fragrance are as follows: 0-2 points for very weak, 2-4 points for weak, 4-6 points for medium, 6-8 points for strong, and 8-10 points for very strong.

[0123] Table 4

[0124] Alcoholic Malty Saucey Esters Sweet Amines Example 1 6.2 8.7 9.4 6.3 8.1 1.6 Example 2 7.8 7.4 8.8 6.9 8.5 1.3 Example 3 7.2 8.5 9.0 7.2 7.9 1.9 Example 4 8.4 8.9 7.3 5.8 6.6 2.6 Example 5 6.6 7.4 8.0 5.9 7.6 2.5 Example 6 7.5 7.5 8.8 6.8 5.8 3.6 Example 7 8.4 8.2 9.0 7.0 6.5 3.5 Example 8 8.0 7.8 9.1 5.9 7.4 2.9 Example 9 9.5 6.4 8.7 6.6 6.5 2.4 Example 10 6.8 5.3 7.9 5.2 7.8 2.8 Comparative Example 1 7.3 6.0 8.5 4.9 5.0 5.2 Comparative Example 2 6.5 4.9 8.2 5.5 4.4 4.1 Comparative Example 3 6.3 4.5 7.6 6.2 3.9 4.8 Comparative Example 4 7.0 5.5 7.5 5.4 4.6 5.4

[0125] The above results show that the peanut meal antibacterial masterbatch provided by this invention can effectively resist spoilage microbial contamination during the soy sauce koji-making process. Furthermore, the mixing of the antibacterial masterbatch with oatmeal promotes ventilation, which is beneficial for the growth of Aspergillus oryzae and reduces the likelihood of koji burning. Therefore, sensorily, the amine flavor is significantly reduced, and excessive alcoholic fermentation does not mask other flavors with an alcoholic taste. The soy sauce aroma, sweet aroma, and malt aroma are more prominent, resulting in a more balanced overall flavor.

[0126] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing koji for soy sauce, characterized in that, The method includes: mixing starchy raw materials, fermenting agents, starter culture, and granules with koji-making function in a second mixing process, and then piling and fermenting the mixture to obtain koji; The method for preparing the granules with the function of promoting koji making includes: (1) Dry-steam the protein raw materials used for koji making; (2) The dry-steamed protein raw material for koji making is mixed with plant-derived antibacterial components, and the first mixture is granulated. The plant-derived antibacterial component is selected from onion extract and garlic extract; The preparation method of the plant-derived antibacterial component includes: mixing the raw material to be extracted with water and juicing it; The mass ratio of the raw material to be extracted to water is 1:(1-1.5); the raw material to be extracted includes onions and garlic, and the mass ratio of onions to garlic is 3:(1-1.5). In step (1), the dry steaming temperature is 115-126℃, the time is 0.3-0.5h, and the pressure is 0.08-0.15MPa; The protein raw material used for koji making is peanut meal; the mass content of the protein raw material used for koji making is 70-80 wt% relative to the total mass of the first mixed product; the mass content of the plant-derived antibacterial component is 10-15 wt% relative to the total mass of the first mixed product. Granulation results in a particle size of 0.5-1 cm; The fermenting agent is *Lactobacillus plantarum*; the starter culture is *Aspergillus oryzae* starter culture.

2. The method according to claim 1, wherein, In step (2), the first mixing also includes the operation of introducing a granulation aid into the mixing system.

3. The method according to claim 2, wherein, The granulation aid is flour.

4. The method according to claim 2, wherein, The mass content of the granulation aid is 10-15 wt% relative to the total mass of the first mixture.

5. The method according to claim 1, wherein, The starchy raw material is roasted oatmeal; The mass ratio of granular and starchy raw materials that promote koji-making is (1-1.5):

1.

6. The method according to claim 1, wherein, The amount of the fermenting agent is such that, in the second mixture, the initial content of the fermenting agent is 1 × 10⁻⁶. 6 -1×10 7 cfu / g.

7. The method according to claim 6, wherein, The amount of Aspergillus oryzae inoculum used is such that the initial content of Aspergillus oryzae in the second mixed material is 1×10⁻⁶. 8 -5×10 8 cfu / g; The stacking fermentation method includes: after a first culture at 30-32℃ for 12-15 hours, turning the koji, and then carrying out a second culture.

8. The method according to claim 7, wherein, The second cultivation method includes: culturing at 28-30℃ for 6-9 hours, followed by a second turning, and then continuing cultivation for another 12-14 hours.

9. A method for preparing soy sauce, characterized in that, The method includes: mixing brine and soy sauce prepared by the method according to any one of claims 1-8 with koji and fermenting.

10. The method according to claim 9, wherein, The fermentation temperature is 28-32℃, and the time is 170-190 days.

11. The soy sauce prepared by the method of claim 9 or 10.

12. The soy sauce according to claim 11, wherein, The soy sauce contains 1.57-1.68 g / 100 mL of total nitrogen.

13. The soy sauce according to claim 12, wherein, The soy sauce contains 1.25-1.33 g / 100 mL of amino acid nitrogen.

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