A koji-making method for increasing protease content

Abstract

The application provides a koji making method for improving protease content, and belongs to the technical field of condiment manufacturing. The koji making method for improving protease content comprises the following steps: preparing protein soybean raw materials and starch wheat raw materials, inoculating Aspergillus oryzae, mixing and stirring, and then carrying out koji making; the koji making is divided into a first culture stage, a second culture stage, a third culture stage and a fourth culture stage according to koji making time; the first culture stage is 0-13 hours of koji making; the second culture stage is 14-21 hours of koji making; the third culture stage is 22-30 hours of koji making; and the fourth culture stage is 31-44 hours of koji making. The application mainly designs oxygen demand of Aspergillus oryzae at different growth stages, combines heat production rules of Aspergillus oryzae metabolism, and creatively realizes optimization combination of circulating air and fresh air from outside and optimization of air volume at different stages, so that the koji quality is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of condiment manufacturing, and particularly relates to a koji making method for improving protease content. BACKGROUND

[0002] Koji making is a key step in the brewing of condiments such as soy sauce, and is a process of enzyme production by Aspergillus oryzae. Enzymes play a role in decomposing proteins in the liquid fermentation process, and form amino nitrogen and small molecule peptides, which are the main contributors to the umami and thick taste of condiments. The quality of koji making will affect the quality of condiments. CN201510858727.8 discloses a koji making method for soy sauce brewing. The method selects protein raw materials and starch raw materials, mixes them, inoculates microorganisms, and then carries out koji making culture. During the koji making culture process, air is introduced. After the first time of koji loosening, when the temperature of the koji exceeds 35℃, water is added and atomized to reduce the temperature of the koji to 28-32℃ until before the second time of koji loosening. After the second time of koji loosening, when the temperature of the koji rises to above 38℃, the sugar substances on the surface of the koji have been consumed by microorganisms, and a glucose aqueous solution is added and atomized to reduce the temperature of the koji to 28-32℃ until the koji making is completed. The existing koji making process for soy sauce mainly combines the growth law of Aspergillus oryzae, and uses temperature as a judgment standard. The process is controlled by means of air volume and koji loosening, but the air volume of each stage and the control process cannot be reasonably set according to the oxygen demand of Aspergillus oryzae at different stages, so that the most economical and reasonable control process cannot be realized. SUMMARY

[0003] The technical problem to be solved by the application is to provide a koji making method for improving protease content, which solves the problem of low enzyme activity of koji for soy sauce by adjusting the stage-by-stage proportion of circulating air and fresh air in the whole koji making process.

[0004] To achieve the above object, the technical scheme adopted by the application is as follows: a koji making method for improving protease content, comprising the following steps: preparing protein soybean raw materials and starch wheat raw materials, inoculating Aspergillus oryzae, mixing and stirring the materials, and then carrying out koji making; and in each culture stage of the koji making, the opening degree of the return air valve and the opening degree of the fresh air valve are controlled according to the oxygen demand of Aspergillus oryzae at each culture stage, so as to control the oxygen concentration and the air supply volume.

[0005] As a preferred embodiment of the koji-making method for improving protease content, the koji-making is divided into a first culture stage, a second culture stage, a third culture stage and a fourth culture stage according to the koji-making time; the first culture stage is 0-13 h of koji-making; the second culture stage is 14-21 h of koji-making; the third culture stage is 22-30 h of koji-making; and the fourth culture stage is 31-44 h of koji-making. The koji-making of soy sauce is carried out by inoculating Aspergillus oryzae on koji materials, and in this process, proteases required for soy sauce production are secreted. If the koji-making process is not well controlled, the quality and enzyme activity of the koji will affect the quality of the soy sauce. Temperature, humidity and air have a great influence on the koji-making process. Most of the existing koji-making processes of soy sauce are based on temperature as the judgment standard, and the whole process is controlled by means of air volume and loose koji, etc. Ventilation has the functions of cooling and oxygen supply in the koji-making process. The present application combines the oxygen metabolism demand of Aspergillus oryzae growth and metabolism process, adjusts the stage ratio of circulating air and fresh air in the whole koji-making process, superimposes the air volume control, meets the oxygen metabolism demand of the whole Aspergillus oryzae growth and metabolism process, and thus realizes the stable improvement of the overall quality.

[0006] As a preferred embodiment of the koji-making method for improving protease content, in the first culture stage, the oxygen concentration is 17-19% within 0-8 h, the return air valve opening degree is 60-80%, the external fresh air valve opening degree is 20-40%, and the air supply volume is 40000-80000 m 3 / h; and the oxygen concentration is 19-21% within 9-13 h, the return air valve opening degree is 10-30%, the external fresh air valve opening degree is 70-90%, and the air supply volume is 80000-160000 m 3 / h.

[0007] As a preferred embodiment of the koji-making method for improving protease content, in the second culture stage, the oxygen concentration is 19-21%, the return air valve opening degree is 15-35%, the external fresh air valve opening degree is 65-85%, and the air supply volume is 120000-160000 m 3 / h.

[0008] As a preferred embodiment of the koji-making method for improving protease content, in the third culture stage, the oxygen concentration is 18-20%, the return air valve opening degree is 0-20%, the external fresh air valve opening degree is 80-100%, and the air supply volume is 100000-140000 m 3 / h.

[0009] As a preferred embodiment of the koji making method for improving protease content, in the fourth culture stage, the oxygen concentration is 17-19%, the return air valve opening is 20-40%, the external fresh air valve opening is 60-80%, and the air supply is 60000-100000 m 3 / h.

[0010] The application further provides a soy sauce koji prepared by the koji making method for improving protease content.

[0011] The application further provides application of the soy sauce koji in preparing a condiment.

[0012] As a preferred embodiment of the application, the condiment comprises soy sauce.

[0013] The application further provides a soy sauce fermented by the soy sauce koji.

[0014] The application has the following beneficial effects: the application provides a koji making method for improving protease content, which mainly designs oxygen demand in different growth stages of Aspergillus oryzae, combines heat production rules of Aspergillus oryzae metabolism, and creatively realizes optimization combination of circulating air and external fresh air and optimization of air volume in different stages, so as to improve koji quality; the application takes temperature demand of Aspergillus oryzae growth as a basis, takes oxygen content demand in different stages as a judgment condition, and creatively realizes stage optimization of circulating air and external fresh air and air volume control, so as to meet control requirements and realize economy of air supply volume. DETAILED DESCRIPTION

[0015] In order to more simply and clearly show the technical scheme, object and advantages of the application, the technical scheme of the application is described in detail below in combination with specific examples. Unless otherwise specified, the reagents involved in the examples of the application are all commercially available and can be purchased through commercial channels.

[0016] Example 1

[0017] The preparation method of the soy sauce raw oil in this embodiment specifically comprises the following steps:

[0018] S1: Protein soybean raw material preparation: remove impurities from soybeans and soak them (soaking ratio 110-130%);

[0019] S2: Cooking: cook the treated soybean raw material in S1, the cooking conditions are 120-140℃, 0.18-0.30MPa, and the cooking time is 10-90s, so that the protein is denatured moderately and microorganisms attached to the raw material are killed, and after the cooking is completed, the cooked material is cooled to 30℃-36℃, obtaining soybean cooked material;

[0020] S3: Starchy wheat raw material preparation: remove impurities, roast, cool, crush, and obtain wheat flour;

[0021] S4: Seed dressing: mix 0.1% to 0.3% of the Aspergillus oryzae inoculum after pure culture expansion with the wheat flour of S3, mix evenly, and then mix with the treated soybean material of S2 to obtain the material;

[0022] S5: Mixed material: evenly distribute and lay the material of S4 in the koji pool or disc for koji making;

[0023] S6: Koji making: koji making is divided into four culture stages, and the specific conditions and parameters of each culture stage are as follows:

[0024] First culture stage: 0-8h of koji making: koji material temperature is 33-35℃, oxygen concentration is 19%, return air valve opening is 60%, external fresh air valve opening is 40%, and air supply is 50000m 3 / h; 9-13h of koji making: koji material temperature is 35-40℃, oxygen concentration is 21%, return air valve opening is 10%, external fresh air valve opening is 90%, and air supply is 100000m 3 / h, and the koji material is stirred and turned for the first time at 11-13h of growth;

[0025] Second culture stage: 14-21h of koji making: koji material temperature is 28-35℃, oxygen concentration is 21%, return air valve opening is 15%, external fresh air valve opening is 85%, and air supply is 130000m 3 / h;

[0026] Third culture stage: 22-30h of koji making: koji material temperature is 26-33℃, oxygen concentration is 20%, return air valve opening is 0%, external fresh air valve opening is 100%, and air supply is 110000m 3 / h, and the koji material is stirred and turned for the third time at 30h of growth;

[0027] Fourth culture stage: 31-44h of koji making: koji material temperature is 26-32℃, oxygen concentration is 19%, return air valve opening is 20%, external fresh air valve opening is 80%, and air supply is 80000m 3 / h, and the koji is formed at 40-44h of growth;

[0028] S7: Fermentation: high-salt dilute fermentation method is adopted, the soy sauce koji of S6 is mixed with salt water with a salt concentration of 19-23% to obtain a mixture, and the koji: salt water = 1:(1.5-2.2). The fermentation temperature is 30-38℃, and the time is 50-80 days.

[0029] Example 2

[0030] The soy sauce raw material preparation method of the embodiment specifically comprises the following steps:

[0031] S1: Protein soybean raw material preparation: remove impurities from soybeans and soak them (soaking ratio 110-130%);

[0032] S2: Cooking: cook the soybean raw material treated in S1, with cooking conditions of 120-140°C, 0.18-0.30 MPa, and cooking time of 10-90 s, so as to make the protein denature moderately and kill the microorganisms attached to the raw material. After the cooking is completed, cool the cooked material to 30-36°C to obtain soybean cooked material;

[0033] S3: Starchy wheat raw material preparation: remove impurities from wheat, roast, cool, and crush to obtain wheat flour;

[0034] S4: Seed mixing: mix the wheat flour of S3 with the koji prepared by pure culture expansion of Aspergillus oryzae seeds at 0.1%-0.3%, and then mix the mixture with the soybean cooked material treated in S2 to obtain the material;

[0035] S5: Mixing and stirring the material: evenly distribute and lay the material of S4 in a koji pit or a disc for koji making;

[0036] S6: Koji making: koji making is divided into four culture stages, and the specific conditions of each culture stage are as follows:

[0037] First culture stage: 0-8 h of koji making: koji temperature 33-35°C, oxygen concentration 18%, return air valve opening 70%, external fresh air valve opening 30%, and air supply 50000 m 3 / h; 9-13 h of koji making: koji temperature 35-40°C, oxygen concentration 21%, return air valve opening 20%, external fresh air valve opening 80%, and air supply 100000 m 3 / h, and the koji is stirred and turned for the first time when it grows to 11-13 h according to the sensory evaluation;

[0038] Second culture stage: 14-21 h of koji making: koji temperature 28-35°C, oxygen concentration 20%, return air valve opening 25%, external fresh air valve opening 75%, and air supply 130000 m 3 / h, and the koji is stirred and turned for the second time when it grows to 21 h;

[0039] Third culture stage: 22-30 h of koji making: koji temperature 26-33°C, oxygen concentration 19%, return air valve opening 10%, external fresh air valve opening 90%, and air supply 110000 m 3 / h, when growing to 30h, the koji is stirred for the third time;

[0040] Fourth culture stage: koji 31-44h: koji temperature 26-32℃, oxygen concentration 18%, return air valve opening 30%, external fresh air valve opening 70%; air supply 80000m 3 / h, when growing to 40-44h, the koji is formed;

[0041] S7: fermentation: using high-salt dilute fermentation method, the soy sauce koji of S6 is mixed with salt water with a salt concentration of 19-23%, koji: salt water = 1:(1.5-2.2). The fermentation temperature is 30-38℃, and the time is 50-80 days.

[0042] Example 3

[0043] The method for preparing a soybean crude oil of the present embodiment specifically comprises the following steps:

[0044] S1: protein soybean raw material preparation: remove impurities from soybeans and hydrate (hydration ratio 110-130%);

[0045] S2: cooking: cook the treated soybean raw material in S1, the cooking conditions are 120-140℃, 0.18-0.30MPa, and the cooking time is 10-90s, so that the protein is denatured moderately and microorganisms attached to the raw material are killed, and after the cooking is completed, the cooked material is cooled to 30-36℃, obtaining soybean cooked material;

[0046] S3: starch wheat raw material preparation: remove impurities from wheat, roast, cool, and crush, obtaining wheat flour;

[0047] S4: seed dressing: mix 0.1-0.3% of the Aspergillus oryzae inoculum after pure expansion culture with the wheat flour of S3, mix them evenly, and then mix them evenly with the soybean cooked material after S2 treatment, obtaining the material;

[0048] S5: mixed material mixing: evenly distribute and lay the material of S4 in the koji pool or disc for koji making;

[0049] S6: koji making: koji making is divided into four culture stages, and the specific conditions and parameters of each culture stage are as follows:

[0050] First culture stage: 0-8h of koji making: koji temperature 33-35℃, oxygen concentration 17%, return air valve opening 80%, external fresh air valve opening 20%, air supply 50000m 3 / h; 9-13h of koji making: koji temperature 35-40℃, oxygen concentration 21%, return air valve opening 30%, external fresh air valve opening 70%, air supply 100000m 3 / h, combined with the sensory evaluation of the koji material, when it has grown for 11-13 hours, the koji material is stirred and turned for the first time;

[0051] Second cultivation stage: 14-21 hours of koji making: koji material temperature 28-35℃, oxygen concentration 19%, return air valve opening 35%, outside fresh air valve opening 65%; at 21 hours of growth, the koji material is stirred and turned a second time, with an air supply volume of 130,000 m³ / h. 3 / h;

[0052] Third cultivation stage: 22-30 hours of koji making: koji material temperature 26-33℃, oxygen concentration 18%, return air valve opening 20%, outside fresh air valve opening 80%, air supply volume 110,000 m³ / h. 3 / h, when the growth reaches 30h, the koji material is stirred and turned for the third time;

[0053] Fourth cultivation stage: 31–44 hours of koji making: koji material temperature 26–32℃, oxygen concentration 17%, return air valve opening 40%, external fresh air valve opening 60%; air supply volume 80,000 m³ / h. 3 / h, it takes 40-44h to form a curd;

[0054] S7: Fermentation: High-salt dilute-state fermentation method is adopted. The soy sauce koji from S6 is mixed evenly with brine with a salt concentration of 19-23%, and the ratio of koji to brine is 1:(1.5-2.2). The fermentation temperature is 30-38℃, and the time is 50-80 days.

[0055] Comparative Example 1

[0056] The comparative example of a method for preparing crude soy sauce specifically includes the following steps:

[0057] S1: Preparation of protein soybean raw materials: Remove impurities from soybeans and moisten them with water (moistening ratio 110-130%);

[0058] S2: Cooking: Cook the soybean raw material processed in S1 at 120-140℃, 0.18-0.30MPa, for 10-90 seconds to denature the protein and kill the microorganisms attached to the raw material. After cooking, cool the cooked material to 30-36℃ to obtain cooked soybean material.

[0059] S3: Preparation of starchy wheat raw materials: Remove impurities from wheat, roast, cool, and grind to obtain wheat flour;

[0060] S4: Seed mixing: The seed koji after pure expansion culture of Aspergillus oryzae is premixed with wheat flour from S3 at 0.1% to 0.3%, and then mixed evenly with the cooked soybeans treated in S2 to obtain the material.

[0061] S5: Mixing and stirring: evenly distribute and lay the S4 material in the tank or disc for koji making;

[0062] S6: Koji making: koji making is divided into four cultivation stages, and the specific conditions of each cultivation stage are as follows:

[0063] First cultivation stage: 0-8h of koji making: koji temperature is 33-35℃, 9-13h of koji making: koji temperature is 35-40℃, air supply is controlled at 90000m 3 / h, the proportion of circulating air and fresh air is automatically adjusted according to the deviation between the set temperature and the actual temperature, and the koji is stirred for the first time when it grows to 11-13h;

[0064] Second cultivation stage: 14-21h of koji making: koji temperature is 28-35℃, air supply is 140000m 3 / h, the proportion of circulating air and fresh air is automatically adjusted according to the deviation between the set temperature and the actual temperature, and the koji is stirred for the second time when it grows to 21h;

[0065] Third cultivation stage: 22-30h of koji making: koji temperature is 26-33℃, air supply is 100000m 3 / h, the proportion of circulating air and fresh air is automatically adjusted according to the deviation between the set temperature and the actual temperature, and the koji is stirred for the third time when it grows to 30h;

[0066] Fourth cultivation stage: 31-44h of koji making: koji temperature is 26-32℃, air supply is 90000m 3 / h, the proportion of circulating air and fresh air is automatically adjusted according to the deviation between the set temperature and the actual temperature, and the koji is stirred for the third time when it grows to 30h;

[0067] S7: Fermentation: high-salt dilute fermentation method is used, the koji of S6 is mixed with salt water with a salt concentration of 19-23%, and the ratio of koji to salt water is 1:(1.5-2.2). The fermentation temperature is 30-38℃, and the time is 50-80 days.

[0068] Comparative examples 2-3

[0069] The preparation method of soy sauce raw oil of comparative examples 2-3 is the same as that of comparative example 1.

[0070] Effect example

[0071] In this effect example, the koji making related parameters in the preparation process of soy sauce raw oil of examples 1-3 and comparative examples 1-3, and the related parameters of raw oil obtained by koji making and fermentation are detected, and the results are shown in Table 1.

[0072] Table 1

[0073]

[0074] From Table 1, it can be seen that the koji preparation methods of Examples 1-3 for improving protease content according to the present application can significantly improve the cell amount, pH and neutral protease enzyme activity of the prepared koji compared with the comparative examples, and the content of amino nitrogen and total nitrogen of the prepared soy sauce raw oil is higher than that of the comparative examples. In summary, the present application adjusts the phase ratio of circulating air and fresh air in the whole koji preparation process, and controls the air volume in the stacking process, so that the quality of the koji and the prepared raw oil is improved.

[0075] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A koji-making method for increasing the content of a protease, characterized by, The method comprises the following steps: Preparation of protein soybean raw materials and starch wheat raw materials, inoculation of Aspergillus oryzae mixed material, and koji making; During each culture stage of koji making, the opening degree of return air valve and the opening degree of external fresh air valve are controlled according to the oxygen required by Aspergillus oryzae in each culture stage, so as to control the oxygen concentration and the air supply; The koji making is divided into a first culture stage, a second culture stage, a third culture stage and a fourth culture stage according to the koji making time; the first culture stage is 0-13 h of koji making; the second culture stage is 14-21 h of koji making; the third culture stage is 22-30 h of koji making; and the fourth culture stage is 31-44 h of koji making; The oxygen concentration is 17-19% in 0-8h of the first culture stage, the air supply is 40000-50000m 3 / h, the return air valve opening is 60-80%, and the external fresh air valve opening is 20-40%; the oxygen concentration is 19-21% in 9-13h, the air supply is 80000-100000m 3 / h, the return air valve opening is 10-30%, and the external fresh air valve opening is 70-90%. In the second culture stage, the oxygen concentration is 19-21%, the air supply is 120000-130000 m 3 / h, the return air valve opening is 15-35%, and the external fresh air valve opening is 65-85%. In the third culture stage, the oxygen concentration is 18-20%, the air supply is 100000-110000 m 3 / h, the return air valve opening is 0-20%, and the external fresh air valve opening is 80-100%. In the fourth culture stage, the oxygen concentration is 17-19%, the air supply is 60000-80000m 3 / h, the return air valve opening is 20-40%, and the external fresh air valve opening is 60-80%.

2. A koji for soy sauce, characterized by, The koji making method for improving protease content is used for preparation.

3. Use of the koji of claim 2 in the preparation of condiments.

4. Use according to claim 3, characterized in that, The condiments include soy sauce.

5. A sauce, characterized by The koji of claim 2 is used for fermentation.

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