Aspergillus culture technology for improving protease activity of soy sauce koji

Abstract

The invention relates to an aspergillus culture technology for improving protease activity of soy sauce koji, and particularly provides a disc koji-making method which comprises a step of performing disc culture on a mixture, the mixture comprises raw materials and koji seeds, two rounds of koji loosening are performed in the disc culture process, during the first round of koji loosening, the koji loosening frequency is 2-5 times, and during the second round of koji loosening, the koji loosening time is 2-5 times; the koji loosening auger is used for loosening the koji during the first koji loosening, and the koji loosening auger and the koji loosening rake are matched for loosening the koji during the second and later koji loosening; and during the second round of koji loosening, the koji loosening times are 1-5 times, and koji loosening is performed by matching a koji loosening auger with a koji loosening rake during each time of koji loosening.

Description

Technical Field

[0001] The invention belongs to the technical field of condiment production, and particularly relates to an Aspergillus culture technology for improving the activity of soy sauce koji protease. Background Art

[0002] Koji making is the core link in soy sauce brewing. Koji making can cultivate a large number of Aspergillus oryzae strains, which can secrete rich enzymes and provide the necessary biochemical reaction conditions for the subsequent fermentation process. At the same time, koji making can also ensure that the quality and flavor of soy sauce are in the best state. Therefore, koji making is an indispensable step in the soy sauce brewing process.

[0003] As an aerobic microorganism, Aspergillus oryzae needs oxygen to support its growth and metabolic activities. During the koji making process, the koji material is easily lumped together due to the mycelium wrapping it, which prevents the koji material from dissipating heat and causes heartburn. In addition, the internal mycelium cannot come into contact with oxygen, which hinders the growth and reproduction of Aspergillus oryzae and easily causes infection by other bacteria, reducing the enzyme activity of the koji material.

[0004] At present, there are mainly six technologies to improve the activity of koji proteinase:

[0005] (1) By adjusting different air volumes during the koji material cultivation process: CN115678787A introduces a method for increasing the oxygen content of Aspergillus oryzae and thus increasing the enzyme production capacity of Aspergillus oryzae and ultimately improving the protease activity of the koji material by adjusting the ratio of fresh air from the outside to internal circulating air at different stages during the koji making process. However, this method will reduce the temperature of the koji material by increasing the fresh air from the outside. If the temperature of the koji material is low in winter and it needs to be heated, the energy consumption will increase and the cost of koji making will increase, so there will be certain limitations in practical application.

[0006] (2) Improving the activity of koji enzyme by reducing the number of microorganisms in the koji raw materials: CN102406153A introduces a method for sterilizing cooked soybeans immediately after they are taken out of the pot, thereby reducing the number of microorganisms in the raw materials and strengthening the growth of the target bacteria, and finally improving the activity of the koji protease. However, this method causes the raw materials and the koji bacteria to be mixed unevenly, and the proportion of the koji bacteria in the entire koji raw materials is relatively low. The efficiency of mixing the cooked soybeans with the raw materials and then with the added seeds is not high, and the koji bacteria cannot fully utilize the raw materials for growth, which reduces the utilization efficiency of the raw materials.

[0007] (3) Improving the enzyme production capacity of Aspergillus oryzae by adding activators: CN103798739A introduces a method of activating the enzyme system inside the koji-making fungus by adding pantothenic acid, tomato pomace and inorganic salts during the koji-making process, thereby promoting enzyme production and increasing the protease content of the koji material. However, this method will add additional additives, which will be added to the ingredient list of the finished soy sauce, which may reduce the competitiveness of the finished product, so there will be limitations in practical application.

[0008] (4) Improving the activity of protease in koji material by adding soy whey protein peptide: CN101297690A introduces a method of adding soy whey protein peptide in the koji making process to improve the enzyme production capacity of Aspergillus oryzae and ultimately improve the protease activity of koji material. However, the soy protein peptide prepared by this method needs to go through the steps of concentration, enzyme inactivation and spray drying, which increases the cost of koji making, so there are certain limitations in actual operation.

[0009] (5) Improving the pH of the koji material to increase the protease: CN117461826A introduces a method of spraying alkali solution and acetic acid during the koji making process to control the pH of the koji material, so as to improve the enzyme production capacity of Aspergillus oryzae and ultimately increase the protease of the koji material. However, this method increases the cost of koji making, and the pH control during the koji making process is more difficult, so it has certain limitations in actual operation.

[0010] (6) Improving the activity of protease in koji by adding protein-rich additives: CN1857113A introduces a method for increasing the activity of protease in the process of making koji for soy sauce, which includes adding additives during the preparation of raw materials, the preparation of strains, or the mixing of raw materials and strains, or adding a certain amount of additives during the above stages, with the amount of additives accounting for 0.5%-20% of the total amount of raw materials. By adding appropriate protein-rich additives, the activity of protease in the koji process is greatly improved, thereby increasing the yield of soy sauce. However, this method increases production costs by adding additional additives, so it has certain limitations in actual operation.

[0011] Therefore, the technology to enhance the activity of koji proteinase needs further research and development. Summary of the invention

[0012] In order to solve the problems existing in the above prior art, the inventors of the present application have provided a new method for making koji through experimental research, and surprisingly found that in the two-round loosening process of the koji making method of the present invention, the choice of the timing of the loosening auger and the loosening rake in the first round of loosening has a significant impact on the performance of the finished koji. The inventors of the present application found that in the first round of loosening, compared with lowering the auxiliary rake to assist in loosening the koji from the first time of loosening the koji, the auxiliary rake was lowered to start assisting in loosening the koji in the second time of loosening the koji, and the spore count and enzyme activity of the finished koji were significantly improved, and the particle size of the koji material was significantly reduced (to less than 50%), achieving an unexpected improvement in effect.

[0013] Thus, in a first aspect, the present invention provides a disc koji making method, comprising the step of disc culturing a mixture, the mixture comprising raw materials and seed koji, and performing two rounds of koji loosening steps during the disc culturing process, wherein:

[0014] In the first round of loosening, the number of loosening is 2-5 times. The first time of loosening is to use a loosening auger. The second and subsequent times of loosening are to use a loosening auger and a loosening rake.

[0015] In the second round of loosening, the number of loosening times is 1-5 times, and each time the loosening is done with a loosening auger and a loosening rake.

[0016] In some embodiments, the first round of loosening is performed 2-3 times, the first loosening is performed using a loosening auger, and the second and subsequent loosening are performed using a loosening auger in combination with a loosening rake.

[0017] In the second round of loosening, the number of loosening is 2-3 times, and each time the loosening is performed using a loosening auger and a loosening rake.

[0018] In some embodiments, the first round of loosening is performed three times, the first time a loosening auger is used to loosen the hair, and the second to third times a loosening auger and a loosening rake are used in combination to loosen the hair.

[0019] In some embodiments, the second round of loosening is performed twice, and each time the loosening is performed using a loosening auger in combination with a loosening rake.

[0020] Furthermore, the inventors of the present application have also found that in the koji making method of the present invention, the rake clearance during the two rounds of loosening, especially the second round, also has a significant impact on the performance of the finished koji. Selecting a suitable rake clearance can further significantly increase the spore count and enzyme activity of the finished koji, and further significantly reduce the particle size of the koji (e.g., to less than 50%), which is beneficial to the later increase of amino nitrogen in the fermented crude oil.

[0021] Thus, in some embodiments, in the first round of loosening, the gap of the loosening rake is 3-10 cm (such as 3-5 cm, 3-7 cm, 3-10 cm, 5-7 cm, 5-10 cm or 7-10 cm, or such as 3 cm, 5 cm, 7 cm or 10 cm), and in the second round of loosening, the gap of the loosening rake is 3-10 cm (such as 3-5 cm, 3-7 cm, 3-10 cm, 5-7 cm, 5-10 cm or 7-10 cm, or such as 3 cm, 5 cm, 7 cm or 10 cm).

[0022] In some embodiments, in the first round of loosening, the gap of the loosening rake is 3-5 cm.

[0023] In some embodiments, in the first round of loosening, the gap of the loosening rake is 3 cm.

[0024] In some embodiments, in the second round of loosening, the gap of the loosening rake is 3-5 cm.

[0025] In some embodiments, in the second round of loosening, the gap of the loosening rake is 3 cm.

[0026] In some embodiments, in the first round of deflexion, the total deflexion time is 50-100 min (such as 50-70 min, 50-90 min, 50-100 min, 70-90 min, 70-100 min or 90-100 min, or such as 50 min, 70 min, 90 min or 100 min).

[0027] In some embodiments, in the first round of loosening, the total time of the loosening is 70 minutes.

[0028] In some embodiments, in the second round of deflexion, the total deflexion time is 50-90 min (such as 50-70 min or 70-90 min, or such as 50 min, 70 min or 90 min).

[0029] In some embodiments, in the second round of loosening, the total time of the loosening is 50 minutes.

[0030] In some embodiments, in the first round of loosening, when the number of loosening is greater than 1, the time of each loosening is the same.

[0031] In some embodiments, in the second round of loosening, when the number of loosening is greater than 1, the time of each loosening is the same.

[0032] In some embodiments, in the first round of loosening, when the number of loosening is greater than 1 time, multiple loosenings are performed continuously.

[0033] In some embodiments, in the second round of loosening, when the number of loosening is greater than 1, multiple loosenings are performed continuously.

[0034] In some embodiments, in the first round of loosening, the loosening frequency is 30-60 Hz (such as 30-40 Hz, 30-50 Hz, 30-60 Hz, 40-50 Hz, 40-60 Hz or 50-60 Hz, or such as 30 Hz, 40 Hz, 50 Hz or 60 Hz).

[0035] In some embodiments, in the first round of loosening, the loosening frequency is 50 Hz.

[0036] In some embodiments, in the second round of loosening, the loosening frequency is 30-70 Hz (such as 30-40 Hz, 30-50 Hz, 30-60 Hz, 30-70 Hz, 40-50 Hz, 40-60 Hz, 40-70 Hz, 50-60 Hz, 50-70 Hz or 60-70 Hz, or such as 30 Hz, 40 Hz, 50 Hz, 60 Hz or 60 Hz).

[0037] In some embodiments, in the second round of loosening, the loosening frequency is 40 Hz.

[0038] In some embodiments, in the first round of loosening, the loosening fan frequency is 50-70 Hz (such as 50-60 Hz or 60-70 Hz, or such as 50 Hz, 60 Hz or 70 Hz).

[0039] In some embodiments, in the first round of loosening, the loosening fan frequency is 60 Hz.

[0040] In some embodiments, in the second round of loosening, the loosening fan frequency is 30-60 Hz (such as 30-40 Hz, 30-50 Hz, 30-60 Hz, 40-50 Hz, 40-60 Hz or 50-60 Hz, or such as 30 Hz, 40 Hz, 50 Hz or 60 Hz).

[0041] In some embodiments, in the second round of loosening, the loosening fan frequency is 40 Hz.

[0042] In some embodiments, the first round of loosening and the second round of loosening are performed at a temperature of 25-38°C (such as 25-27°C, 25-30°C, 25-33°C, 25-36°C, 25-38°C, 27-30°C, 27-33°C, 27-36°C, 27-38°C, 30-33°C, 30-36°C, 30-38°C, 33-36°C, 33-38°C or 36-38°C, or such as 25°C, 27°C, 30°C, 33°C, 36°C or 38°C, preferably 36°C).

[0043] In some embodiments, in the first round of loosening, the moisture content of the loosened dough is 80-98% (such as 80-85%, 80-90%, 80-95%, 80-98%, 85-90%, 85-95%, 85-98%, 90-95%, 90-98% or 95-98%, or such as 80%, 85%, 90%, 95% or 98%).

[0044] In some embodiments, in the first round of loosening, the moisture content of the loosened dough is 98%.

[0045] In some embodiments, in the second round of loosening, the moisture content of the loosened dough is 80-98% (such as 80-85%, 80-90%, 80-95%, 80-98%, 85-90%, 85-95%, 85-98%, 90-95%, 90-98% or 95-98%, or such as 80%, 85%, 90%, 95% or 98%).

[0046] In some embodiments, in the second round of loosening, the moisture content of the loosened dough is 95%.

[0047] In some embodiments, the first round of loosening begins when the disc is cultured for 9-13 hours (such as 9-10 hours, 9-11 hours, 9-12 hours, 9-13 hours, 10-11 hours, 10-12 hours, 10-13 hours, 11-12 hours, 11-13 hours or 12-13 hours, or such as 9 hours, 10 hours, 11 hours, 12 hours or 13 hours, preferably 13 hours).

[0048] In some embodiments, the second round of loosening is initiated when the disc is cultured for 15-23 h (such as 15-16 h, 15-18 h, 15-20 h, 15-22 h, 15-23 h, 16-18 h, 16-20 h, 16-22 h, 16-23 h, 18-20 h, 18-22 h, 18-23 h, 20-22 h, 20-23 h or 22-23 h, or such as 15 h, 16 h, 18 h, 20 h, 22 h or 23 h, preferably 16 h).

[0049] In some embodiments, the disc is cultured for 40-50 h (such as 40-43 h, 40-45 h, 40-47 h, 40-50 h, 43-45 h, 43-47 h, 43-50 h, 45-47 h, 45-50 h or 47-50 h, or such as 40 h, 43 h, 45 h, 47 h or 50 h).

[0050] In some embodiments, the disc is cultured for 43 hours.

[0051] In some embodiments, the seed koji is an Aspergillus seed koji.

[0052] In some embodiments, the seed koji is Aspergillus oryzae seed koji.

[0053] In some embodiments, the raw materials include soybeans and wheat.

[0054] In some embodiments, the weight ratio of the soybean to the wheat is (6-7): (3-4).

[0055] In some embodiments, the weight ratio of the Aspergillus oryzae seed koji, the soybean and the wheat is (0.0006-0.0009):(6-7):(3-4).

[0056] In some embodiments, the weight ratio of the Aspergillus oryzae seed, the soybean and the wheat is 0.0008:7:3.

[0057] In some embodiments, the soybeans are pre-moistened and steamed.

[0058] In some embodiments, the wheat is roasted and crushed in advance.

[0059] In a second aspect, the present invention provides a finished song, which is prepared by the method described in any technical solution of the first aspect.

[0060] In a third aspect, the present invention provides use of the finished koji described in the second aspect in preparing condiments.

[0061] In some embodiments, the condiment is selected from soy sauce and paste.

[0062] In some embodiments, the condiment is soy sauce.

[0063] In a fourth aspect, the present invention provides a condiment obtained by fermenting the koji described in the second aspect.

[0064] In some embodiments, the condiment is selected from soy sauce and paste.

[0065] In some embodiments, the condiment is soy sauce. Beneficial Effects

[0066] 1. In the koji making method of the present invention, the timing of the coordination of the koji loosening auger and the koji loosening rake in the first round of koji loosening has a significant impact on the performance of the finished koji. In the first round of koji loosening, compared with lowering the auxiliary rake to assist in koji loosening from the first round of koji loosening, the auxiliary rake is lowered to assist in koji loosening in the second round of koji loosening. The spore count and enzyme activity of the finished koji are significantly improved, and the particle size of the koji material is significantly reduced (reduced to less than 50%), which achieves an unexpected effect improvement, which is beneficial to the later increase of amino nitrogen in the fermented crude oil.

[0067] 2. In the koji making method of the present invention, during the two rounds of loosening, especially the second round, the rake clearance also has a significant impact on the performance of the finished koji. Selecting a suitable rake clearance can further significantly increase the spore count and enzyme activity of the finished koji, and further significantly reduce the particle size of the koji (to less than 45%), which is beneficial to the later increase of amino nitrogen in the fermented crude oil.

[0068] 3. The process technology of the present invention is relatively simple, can avoid the addition of additional additives and energy consumption, can save costs, and ultimately can not only greatly improve the enzyme activity of the koji material, but also the final product does not contain any additional additives.

[0069] 4. The method of the present invention can reduce the particle size of the koji material (to below 50%, or even below 45%) by combining the koji loosening auger with the koji loosening auxiliary rake at an appropriate time and further optimizing the rake gap, so that Aspergillus oryzae can fully combine with oxygen, improve the growth ability of Aspergillus oryzae, and enable it to grow fully. There is no need for other additives, no increase in energy consumption, low adjustment cost, and greatly improved fermentation efficiency. DETAILED DESCRIPTION

[0070] The following specific examples further illustrate the present invention, and it should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The test methods for which specific conditions are not specified in the following examples are usually performed under normal conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, all raw materials and equipment are commercially available. Unless otherwise stated, all percentages, ratios, ratios, or portions are by weight.

[0071] In the present invention, the preparation process of Aspergillus oryzae seed koji comprises the following steps: using bran, soybean meal and water in a certain proportion, mixing and stirring them uniformly, and then evenly distributing them into a koji plate; using a koji seed machine for steaming and sterilization; cooling and lowering the temperature after sterilization; using compressed air to blow Aspergillus oryzae strains in a triangular bottle into the koji seed machine for inoculation after reaching an inoculation temperature; and entering a culturing stage after the inoculation is completed, wherein the culturing temperature is controlled at 27-37°C, and the culturing is performed for 60 hours to obtain the Aspergillus oryzae seed koji.

[0072] In the present invention, the koji making process is completed and realized by a disc koji making machine (manufacturer: Guangdong Tianniang Intelligent Equipment Co., Ltd., model: YP20601A).

[0073] In the present invention, "loosening frequency" refers to the frequency of turning the koji blank during the koji making process.

[0074] In the present invention, "the frequency of the fan for loosening the koji" refers to the use of the fan to adjust the air flow, temperature and humidity in the koji room during the koji making process. By adjusting the frequency of the fan, the amount of fresh air entering and the wind speed can be controlled, thereby affecting the fermentation speed and quality of the koji.

[0075] In the present invention, "loosening rake gap" refers to the gap distance between two adjacent teeth of the loosening rake.

[0076] In the present invention, "multiple times" means more than once.

[0077] The present invention provides the following technical solutions:

[0078] After pretreatment, soybeans are mixed with wheat flour and koji fungus and then placed in the koji tray for cultivation. By optimizing and adjusting the loosening parameters, a row of loosening auxiliary rakes is added to the loosening auger during loosening, and the loosening auger and the loosening rake are coordinated at the right time to make the koji loose, reduce ventilation resistance and bacterial infection, and add fresh oxygen. The Aspergillus oryzae in the koji is fully exposed to oxygen, which improves the growth and reproduction ability of Aspergillus oryzae, inhibits the reproduction of bacteria, and ultimately improves the protease activity of the koji. The koji after cultivation is mixed with brine and pumped to the fermentation tank for fermentation.

[0079] The present invention also provides the following technical solutions:

[0080] 1. Raw material pretreatment

[0081] The soybeans are moistened and steamed, mixed with roasted and crushed wheat flour, and then mixed with Aspergillus oryzae koji. The weight ratio of Aspergillus oryzae koji, moistened and steamed soybeans, and roasted and crushed wheat flour is (0.0006-0.0009): (6-7): (3-4), and finally transported to the disc culture.

[0082] 2. Cultivation of Aspergillus oryzae

[0083] The room temperature is adjusted to 25-38℃, and the first round of loosening is carried out in 9-13h, and the total time of loosening is 50-100 min, 2-5 times of loosening (multiple loosening is carried out continuously, and the time of each loosening is the same), loosening frequency is 30-60Hz, loosening fan frequency is 50-70Hz, loosening humidity is 80-98%, the rake on the loosening auger descends to cooperate with the auger during loosening, the spacing between loosening rakes is 3-10cm, adjust the timing of rake lowering, and lower the loosening rake to cooperate with the loosening auger during the 2nd to 5th times of loosening; carry out the second round of loosening at 15-23h, the total time of loosening is 50-90min, loosening is carried out 1-5 times (multiple loosening is carried out continuously, and the time of each loosening is the same), loosening frequency is 30-70Hz, loosening fan frequency is 30-60Hz, loosening humidity is 80-98%, the loosening auger is coordinated with the loosening rake, the spacing between loosening rakes is 3-10cm, adjust the timing of rake lowering, and lower the loosening rake to cooperate with the loosening auger during the 1st to 5th times of loosening. After optimization, the particle size of the koji material is moderate, and the growth, reproduction and enzyme production capacity of Aspergillus oryzae are significantly improved.

[0084] The present invention is further explained below with reference to specific embodiments. Embodiment 1:

[0085] 1. Raw material pretreatment

[0086] The soybeans are moistened and steamed, and then mixed with roasted and crushed wheat flour and Aspergillus oryzae seed koji, the weight ratio of Aspergillus oryzae seed koji, moistened and steamed soybeans, and roasted and crushed wheat flour is 0.0008:7:3, and finally transported into the disc culture.

[0087] 2. Cultivation of Aspergillus oryzae

[0088] The temperature in the room was adjusted to 36℃. The first round of loosening was carried out at 13h, with a total time of 70min, 3 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 50Hz, a loosening fan frequency of 60Hz, and a loosening humidity of 98%. In the second loosening, the auxiliary rake was lowered for auxiliary loosening, and the gap between the loosening rakes was 5cm. The second round of loosening was carried out at 16h, with a total time of 50min, 2 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 40Hz, a loosening fan frequency of 40Hz, and a loosening humidity of 95%. From the first time of loosening, the loosening auger was lowered for auxiliary loosening, and the gap between the loosening rakes was 5cm. Mature koji was obtained after 43h of cultivation. Embodiment 2:

[0089] 1. Raw material pretreatment

[0090] The soybeans are moistened and steamed, and then mixed with roasted and crushed wheat flour and Aspergillus oryzae seed koji, the weight ratio of Aspergillus oryzae seed koji, moistened and steamed soybeans, and roasted and crushed wheat flour is 0.0008:7:3, and finally transported into the disc culture.

[0091] 2. Cultivation of Aspergillus oryzae

[0092] The temperature in the room was adjusted to 36℃. The first round of loosening was carried out at 13h, with a total time of 70min, 3 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 50Hz, a loosening fan frequency of 60Hz, and a loosening humidity of 98%. In the second loosening, the auxiliary rake was lowered for auxiliary loosening, and the gap between the loosening rakes was 3cm; the second round of loosening was carried out at 16h, with a total time of 50min, 2 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 40Hz, a loosening fan frequency of 40Hz, and a loosening humidity of 95%. From the first time of loosening, the loosening auger was lowered for auxiliary loosening, and the gap between the loosening rakes was 5cm. Mature koji was obtained after 43h of cultivation. Embodiment 3:

[0093] 1. Raw material pretreatment

[0094] The soybeans are moistened and steamed, and then mixed with roasted and crushed wheat flour and Aspergillus oryzae seed koji, the weight ratio of Aspergillus oryzae seed koji, moistened and steamed soybeans, and roasted and crushed wheat flour is 0.0008:7:3, and finally transported into the disc culture.

[0095] 2. Cultivation of Aspergillus oryzae

[0096] The temperature in the room was adjusted to 36℃. The first round of loosening was carried out at 13h, with a total time of 70min, 3 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 50Hz, a loosening fan frequency of 60Hz, and a loosening humidity of 98%. In the second loosening, the auxiliary rake was lowered for auxiliary loosening, and the gap between the loosening rakes was 3cm. The second round of loosening was carried out at 16h, with a total time of 50min, 2 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 40Hz, a loosening fan frequency of 40Hz, and a loosening humidity of 95%. From the first time of loosening, the loosening auger was lowered for auxiliary loosening, and the gap between the loosening rakes was 3cm. Mature koji was obtained after 43h of cultivation.

[0097] Comparative Example 1:

[0098] 1. Raw material pretreatment:

[0099] The soybeans are moistened and steamed, and then mixed with roasted and crushed wheat flour and Aspergillus oryzae seed koji, the weight ratio of Aspergillus oryzae seed koji, moistened and steamed soybeans, and roasted and crushed wheat flour is 0.0008:7:3, and finally transported into the disc culture.

[0100] 2. Aspergillus oryzae culture:

[0101] The temperature in the room was adjusted to 36℃. The first round of loosening was carried out at 13h, with a total time of 70min, 3 times of loosening (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 50Hz, a loosening fan frequency of 60Hz, and a loosening humidity of 98%; the second round of loosening was carried out at 16h, with a total time of 50min, 2 times of loosening (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 40Hz, a loosening fan frequency of 40Hz, and a loosening humidity of 95%. After 43h of cultivation, mature koji was obtained. There was no loosening auxiliary rake in this process.

[0102] Comparative Example 2:

[0103] 1. Raw material pretreatment:

[0104] The soybeans are moistened and steamed, and then mixed with roasted and crushed wheat flour and Aspergillus oryzae seed koji, the weight ratio of Aspergillus oryzae seed koji, moistened and steamed soybeans, and roasted and crushed wheat flour is 0.0008:7:3, and finally transported into the disc culture.

[0105] 2. Aspergillus oryzae culture:

[0106] The temperature in the room was adjusted to 36℃. The first round of loosening was carried out at 13h, with a total time of 70min, 3 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 50Hz, a loosening fan frequency of 60Hz, and a loosening humidity of 98%. The auxiliary rake was lowered for auxiliary loosening at the first time of loosening, and the gap between the loosening rakes was 5cm. The second round of loosening was carried out at 16h, with a total time of 50min, 2 times (multiple loosenings were carried out continuously, and the time of each loosening was the same), a loosening frequency of 40Hz, a loosening fan frequency of 40Hz, and a loosening humidity of 95%. The loosening auger was lowered for auxiliary loosening at the first time of loosening, and the gap between the loosening rakes was 5cm. Mature koji was obtained after 43h of cultivation.

[0107] The mature koji materials obtained in the above Examples 1-3 and Comparative Examples 1-2 were tested for moisture, pH, koji particle size, koji spore count and enzyme activity. The testing method is as follows:

[0108] (1) Enzyme activity detection:

[0109] SBT 10317-1999 Protease Activity Assay

[0110] (2) Moisture detection:

[0111] GB5009.3—2016 National Food Safety Standard Determination of Water Content in Food

[0112] (3) pH detection:

[0113] GB5009.237—2016 National Food Safety Standard Determination of pH Value of Food

[0114] (4) Spore count detection:

[0115] SBT 10315-1999 Spore count method

[0116] (5) Particle size detection:

[0117] Take 500g of koji material from different positions of the koji-making disc, and sieve it with a 6-mesh sieve until there is no koji material smaller than 6 mesh. Weigh the weight of the material on the 6-mesh sieve and divide it by 500g.

[0118] The test results are shown in Table 1 below.

[0119] Table 1: Test results of mature koji materials of Examples and Comparative Examples

[0120] From the comparison results in the above table, it can be seen that the timing of the coordination between the auger and the rake in the first round of loosening has a significant impact on the performance of the finished koji. In the first round of loosening, compared with lowering the auxiliary rake to assist in loosening the koji from the first time of loosening, lowering the auxiliary rake to assist in loosening the koji in the second time of loosening the koji significantly increased the number of spores and enzyme activity of the finished koji, and the particle size of the koji material was significantly reduced (reduced to less than 50%), achieving an unexpected improvement in effect.

[0121] Furthermore, from the comparison results in the above table, it can be seen that the rake clearance during the two rounds of loosening, especially the second round, also has a significant impact on the performance of the finished koji. Selecting the appropriate rake clearance can significantly increase the spore count and enzyme activity of the finished koji, and significantly reduce the particle size of the koji (to less than 45%).

Claims

1. A disc koji making method, comprising the step of disc culturing a mixture, wherein the mixture comprises raw materials and seed koji, and two rounds of koji loosening steps are performed during the disc culturing process, wherein: In the first round of loosening, the number of loosening is 2-5 times. The first time of loosening is to use a loosening auger. The second and subsequent times of loosening are to use a loosening auger and a loosening rake. In the second round of loosening, the number of loosening times is 1-5 times, and each time the loosening is done with a loosening auger and a loosening rake.

2. The method according to claim 1, wherein: In the first round of loosening, the number of loosening is 2-3 times. The first time of loosening is to use a loosening auger. The second and subsequent times of loosening are to use a loosening auger and a loosening rake. Preferably, in the first round of loosening, the number of loosening is 3 times, the first loosening is performed by using a loosening auger, and the second to third loosening is performed by using a loosening auger in combination with a loosening rake; In the second round of loosening, the number of loosening is 2-3 times, and each time the loosening is performed by using a loosening auger and a loosening rake. Preferably, during the second round of loosening, the number of loosening is 2 times, and each time the loosening is performed using a loosening auger in cooperation with a loosening rake.

3. The method according to claim 1 or 2, wherein: In the first round of loosening, the gap of the loosening rake is 3-10 cm, preferably 3-5 cm, more preferably 3 cm; In the second round of loosening, the gap of the loosening rake is 3-10 cm, preferably 3-5 cm, and more preferably 3 cm.

4. The method according to any one of claims 1 to 3, wherein: The method further has one or more technical features selected from the following (i)-(vi): (i) In the first round of loosening, the total time of the loosening is 50-100 minutes, preferably 70 minutes; (ii) in the second round of loosening, the total time of the loosening is 50-90 minutes, preferably 50 minutes; (iii) In the first round of loosening, if the number of loosening is greater than 1, the duration of each loosening is the same; (iv) In the second round of loosening, if the number of loosening is greater than 1, the duration of each loosening is the same; (v) In the first round of loosening, if the number of loosening is greater than one, multiple loosenings are performed continuously; (vi) In the second round of loosening, if the number of loosening is greater than one, multiple loosenings are performed continuously.

5. The method according to any one of claims 1 to 4, wherein: The method further has one or more technical features selected from the following (i)-(iv): (i) in the first round of loosening, the loosening frequency is 30-60 Hz, preferably 50 Hz; (ii) in the second round of loosening, the loosening frequency is 30-70 Hz, preferably 40 Hz; (iii) in the first round of loosening, the frequency of the loosening fan is 50-70 Hz, preferably 60 Hz; (iv) In the second round of loosening, the frequency of the loosening fan is 30-60 Hz, preferably 40 Hz.

6. The method according to any one of claims 1 to 5, wherein: The method further has one or more technical features selected from the following (i)-(iii): (i) the first round of loosening and the second round of loosening are performed at a temperature of 25 to 38° C. (preferably 36° C.); (ii) in the first round of loosening, the moisture content of the loosened dough is 80-98%, preferably 98%; (iii) In the second round of loosening, the moisture content of the loosened dough is 80-98%, preferably 95%.

7. The method according to any one of claims 1 to 6, wherein: The method further has one or more technical features selected from the following (i)-(v): (i) the first round of loosening begins when the disc is cultured for 9-13 hours (preferably 13 hours); (ii) the second round of loosening begins when the disc is cultured for 15-23 hours (preferably 16 hours); (iii) the disc culture time is 40-50h, preferably 43h; (iv) the seed koji is an Aspergillus seed koji, preferably an Aspergillus oryzae seed koji; (v) the raw materials include soybeans and wheat, Preferably, the weight ratio of the soybean to the wheat is (6-7): (3-4); Preferably, the weight ratio of the Aspergillus oryzae seed koji, the soybean and the wheat is (0.0006-0.0009): (6-7): (3-4); Preferably, the soybeans are pre-moistened and steamed. Preferably, the wheat is roasted and crushed in advance.

8. A finished song prepared by the method according to any one of claims 1 to 7.

9. Use of the finished koji according to claim 8 in preparing condiments; Preferably, the condiment is selected from soy sauce and sauce, preferably soy sauce.

10. A condiment obtained by fermenting the koji according to claim 8; Preferably, the condiment is selected from soy sauce and sauce, preferably soy sauce.

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