Bacteriostat, method of making and using the same, and soy sauce production process

Abstract

The application discloses a bacteriostatic agent, which comprises the following substances in percentage by weight: 18-22% of salt, 0.08-0.12% of edible glue and the rest of water. The application also discloses a method for using the bacteriostatic agent, which comprises the following steps: after the cooking process of soy sauce production is completed, using a conventional cleaning method to clean the cooked beans, bean skins and other substances remaining in the cooking equipment and the discharging equipment; after cleaning, spraying the bacteriostatic agent on the inner wall of the cooking equipment and the discharging equipment, and naturally airing for the next cooking. The maximum salt tolerance concentration of heat-resistant bacteria-bacillus is 12%, and the bacteriostatic measure prepared according to the physiological characteristics has strong pertinence and remarkable effect. The edible glue such as xanthan gum has good adsorption, and the bacteriostatic agent prepared by compounding the edible glue with salt water can relatively durably make the surface of the equipment in a high-salt environment, thereby achieving good bacteriostatic effect.

Description

Technical Field

[0001] This invention relates to the field of soy sauce brewing technology, specifically to an antibacterial agent that can reduce the number of heat-resistant bacteria on the surface of production equipment, the preparation and application method of the antibacterial agent, and the soy sauce production process. Background Technology

[0002] Soy sauce brewing uses oilseed crops as raw materials, and the processes of koji making, fermentation, extraction, and oil filtration are all carried out under open conditions, making it highly susceptible to bacterial contamination. Therefore, effectively controlling microbial contamination during production has always been a key technical challenge for ensuring product hygiene and improving soy sauce clarity and yield. In the past two years, this issue has gradually gained attention from research and production departments.

[0003] Many types of bacteria contaminate soy sauce production, which can be divided into two main categories based on their temperature sensitivity: heat-sensitive bacteria and heat-resistant Bacillus. Heat-sensitive bacteria can be completely killed by pasteurization or at higher temperatures. However, for heat-resistant Bacillus, it is difficult to achieve effective eradication using current sterilization temperatures and times (generally 80-85℃ for 30 minutes). Therefore, simply using high-temperature sterilization to kill bacteria is not ideal.

[0004] Extensive research has been conducted on the physiological characteristics of heat-resistant Bacillus subtilis, and with the aid of appropriate production processes, the growth and reproduction of Bacillus subtilis during soy sauce production can be suppressed to the greatest extent. However, at the same time, the growth of spores on the surfaces of equipment that come into direct contact with the production materials is often overlooked, and there is a lack of research on how to further reduce contamination and microbial growth on equipment surfaces.

[0005] Currently, there are two main methods for inhibiting bacteria: First, thoroughly cleaning the koji-making equipment and disinfecting it with disinfectants such as hypochlorous acid. This method is fundamental for suppressing unwanted bacteria, but it is highly dependent on the operators, leading to inconsistent hygiene levels after cleaning and disinfection. Furthermore, sodium hypochlorite is a toxic and hazardous substance, requiring strict control by relevant departments according to regulations, posing certain safety and management risks to food production enterprises. Second, adding glacial acetic acid during the koji-making and ventilation processes. While this method can effectively inhibit unwanted bacteria, it requires adding steps to the existing production process and introducing exogenous substances, making it more cumbersome. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an antibacterial agent, a method for preparing and using the antibacterial agent, and a soy sauce production process, thereby inhibiting the growth and reproduction of heat-resistant bacteria, reducing the number of heat-resistant bacteria introduced into the soy sauce production process due to contact with equipment surfaces, and improving the number of heat-resistant bacteria in high-salt dilute soy sauce.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0008] An antibacterial agent comprising the following substances in weight percentages: 18%–22% salt, 0.08%–0.12% edible gum, and the remainder being water.

[0009] Furthermore, the salt content is 18%–20% by mass, and the edible gum content is 0.10%–0.12% by mass.

[0010] Furthermore, the salt content is 20%–22% by mass, and the edible gum content is 0.08%–0.10% by mass.

[0011] A method for preparing the above-mentioned antibacterial agent involves weighing 18% to 22% by weight of salt and 0.08% to 0.12% by weight of edible gum powder, mixing the salt and edible gum powder evenly, and then slowly adding the mixture to 100 parts by weight of water that is being stirred, to prepare the antibacterial agent.

[0012] A method for using an antibacterial agent includes washing away residual cooked beans, bean skins, and other substances in the cooking and feeding equipment using conventional cleaning methods after the cooking process in soy sauce production; after cleaning, spraying the inner walls of the cooking and feeding equipment with the aforementioned antibacterial agent and allowing them to air dry naturally for the next cooking use.

[0013] Furthermore, it also includes natural sun-drying during the fermentation process of soy sauce production, followed by re-oiling according to process requirements; after re-oiling, the antibacterial agent is sprayed onto the exposed inner wall of the fermentation tank.

[0014] A soy sauce production process includes the following steps:

[0015] S1. Soaking soybeans: After removing impurities from the soybeans, put them into a soaking pot and add water to soak them;

[0016] S2. Steaming and Cooling: The soaked soybeans are steamed using a reduced pressure steaming method to obtain cooked soybeans, and then the cooked soybeans are cooled.

[0017] S3. Cleaning: Wash away any remaining cooked beans, bean skins, and other substances from the cooking and feeding equipment;

[0018] S4. Spray antibacterial agent: Spray the inner walls of the cooking equipment and feeding equipment with the antibacterial agent and let them air dry naturally for the next cooking use;

[0019] S5. Mixing and Inoculation: Inoculate the cooled cooked beans with the inoculum, add flour, and mix well to obtain the mixture;

[0020] S6. Koji making: The mixture is fed into a thick-layer ventilated fermentation tank for koji making, thereby producing Daqu (large koji).

[0021] S7. Fermentation: The Daqu (a type of starter culture) is sent to a fermentation tank for fermentation. During the fermentation process, a re-oiling operation is performed every 10 to 15 days. After each re-oiling operation, the antibacterial agent is sprayed onto the exposed inner wall of the fermentation tank.

[0022] Furthermore, in step S7, the weight ratio of the amount of Daqu (a type of starter culture) to the amount of antibacterial agent sprayed is 1:0.1~1.

[0023] Further, brine is added to the Daqu (a type of starter culture) prepared in step S6 and mixed evenly. The weight ratio of Daqu to brine is 1:1.5~2.5, and the concentration of brine is 15~25g / 100mL.

[0024] Furthermore, the concentration of the saline solution is 18~22g / 100mL.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) The maximum salt tolerance concentration for heat-resistant bacteria, Bacillus subtilis, is 12%. Antibacterial measures developed based on this physiological characteristic are highly targeted and effective. Edible gums such as xanthan gum have good adsorption properties; when combined with salt water, they create an antibacterial agent that can maintain a relatively long-lasting high-salt environment on equipment surfaces, resulting in a good antibacterial effect.

[0027] 2) Compared with other cleaning and disinfecting agents, brine itself is a raw material for soy sauce brewing, and edible gums such as xanthan gum are also food-grade additives. It is simple to make, non-corrosive to equipment, and poses no food safety hazard. It avoids the introduction of exogenous substances during the production process and greatly reduces the safety and management risks for production enterprises in the process of using toxic and harmful products.

[0028] 3) Introducing antibacterial agents into the soy sauce production process can effectively inhibit the growth of heat-resistant bacteria on the surface of production equipment, thereby reducing the number of heat-resistant bacteria in the process products - Daqu (fermented starter culture) and natural oil, and improving quality and the effective utilization of raw materials. Detailed Implementation

[0029] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] An antibacterial agent comprising the following substances in weight percentages: 18%–22% salt, 0.08%–0.12% edible gum, and the remainder being water.

[0031] This invention adds edible gum to concentrated brine to form a compound antibacterial agent, which improves the adhesion of the antibacterial agent and enables it to exert its antibacterial effect more effectively when in contact with the surface of the equipment.

[0032] Example 1

[0033] Weigh out 180.0g of salt and 12.0g of xanthan gum powder. Mix the salt and xanthan gum powder evenly and then slowly add them to 1L of water that is being stirred to make an antibacterial agent.

[0034] Example 2

[0035] Weigh out 220.0g of salt and 8.0g of xanthan gum powder. Mix the salt and agar powder evenly and slowly add them to 1L of water that is being stirred to make an antibacterial agent.

[0036] Example 3

[0037] Weigh out 200.0g of salt and 10.0g of xanthan gum powder. Mix the salt and xanthan gum powder evenly and then slowly add them to 1L of water that is being stirred to make an antibacterial agent.

[0038] Example 4

[0039] According to daily production monitoring data, the number of heat-resistant bacteria in the cooking and feeding equipment is 10. 4 ~10 5 In this embodiment, the cooking equipment refers to the opening of the cooking pot, and the feeding equipment refers to the feeding trough below the cooking pot. The main reasons are analyzed as follows: the opening of the cooking pot and the feeding trough are under high temperature for a long time during the production process, and non-heat-resistant bacteria are easily killed, leaving only heat-resistant bacteria to survive. In addition, there are residual nutrients from cooked beans in the opening of the cooking pot and the feeding trough, which leads to the large-scale proliferation of heat-resistant bacteria.

[0040] This invention employs the following technical solution for the cooking pot opening and the feeding trough: After the normal production of the cooking process is completed, use a conventional cleaning method (rinsing with tap water) to wash away any residual cooked beans, bean skins, and other substances from the cooking pot opening and the feeding trough below the cooking pot. After cleaning, spray the antibacterial agent from Example 1 onto the inner wall of the cooking pot opening and the feeding trough, and allow it to air dry naturally. This ensures that the clean equipment surface is in a high-salt environment before the next day's production, inhibiting the growth and reproduction of heat-resistant bacteria, thus preparing it for the next cooking use.

[0041] Traditional Cantonese soy sauce uses a high-salt, low-temperature fermentation process. After the raw materials are mixed, they ferment naturally in fermentation tanks under the sun and dew, with the temperature of the mash rising and falling naturally with the ambient temperature. Therefore, during the humid spring season, when the temperature and humidity begin to rise, the fermentation tanks containing the mixed raw materials experience condensation on their inner walls due to the temperature difference between day and night and the increased humidity. This condensation reduces the salt content of the inner walls, allowing heat-resistant bacteria to grow on the surface.

[0042] The present invention adopts the following technical solution for this type of fermentation tank: For fermentation tanks whose fermentation cycle is during the humid season (March-April), after the oil re-oiling operation (once every 10-15 days), the antibacterial agent in Example 1 is sprayed onto the exposed fermentation tank wall (the mixed raw materials in the tank are not full, so a part of the inner wall will not be covered by raw materials), so that the inner wall surface of the fermentation tank is in a high-salt environment, which inhibits the growth and reproduction of heat-resistant bacteria.

[0043] Based on the growth characteristics of the heat-resistant bacterium Bacillus subtilis, this invention creates a high-salt environment on the surface of production equipment during daily production, thereby inhibiting the growth and reproduction of the heat-resistant bacteria, reducing the number of heat-resistant bacteria introduced into the soy sauce production process due to contact with the equipment surface, and improving the number of heat-resistant bacteria in high-salt diluted soy sauce.

[0044] Example 5

[0045] This embodiment is largely the same as embodiment 4, except that the antibacterial agent used in embodiment 2 is sprayed on the inner wall of the cooking pot opening and the feeding trough; and the antibacterial agent used in embodiment 2 is sprayed on the inner wall of the fermentation tank.

[0046] Example 6

[0047] This embodiment is largely the same as embodiment 4, except that the antibacterial agent used in embodiment 3 is sprayed on the inner wall of the cooking pot opening and the feeding trough; and the antibacterial agent used in embodiment 3 is sprayed on the inner wall of the fermentation tank.

[0048] Comparative Example 1

[0049] After the cooking process is completed, use conventional cleaning methods (rinsing with tap water) to wash away any remaining cooked beans, bean skins, and other substances from the opening of the cooking pot and the feeding trough below it, and let them air dry naturally until the next day's production. During the fermentation process, let them air dry naturally, and perform a re-oiling operation as required by the process (once every 10-15 days). Do not perform any other treatment on the walls of the fermentation tank.

[0050] The total number of thermoresistant bacteria-spores was detected by wiping fluid from the surfaces of the equipment involved in the comparative example, example 4, example 5 and example 6 respectively. The specific results are shown in Table 1.

[0051] Table 1. Results of total number of heat-resistant bacteria-spores on the surface of the equipment in the comparative examples and embodiments.

[0052] Unit: cfu / mL

[0053]

[0054] As shown in Table 1, the total number of heat-resistant bacteria (in terms of total spore count) on the surface of the equipment in the embodiment was reduced by 1 to 2 orders of magnitude compared with the control group, showing a significant improvement effect.

[0055] Example 7

[0056] This embodiment provides a method for brewing soy sauce, which mainly uses soybeans and flour as raw materials and obtains the soy sauce through steps such as soaking soybeans, steaming, cooling, mixing and inoculating, making koji, and fermentation.

[0057] The soy sauce brewing method specifically includes the following steps:

[0058] S1. Soaking soybeans: After removing impurities, put the soybeans into a soaking container and add water at 1.5 to 2 times their weight in soybeans. Soak for 4 to 8 hours. Preferably, the soybeans are non-GMO soybeans, and preferably, the soaking water is twice the weight of the soybeans.

[0059] S2. Steaming and Cooling: The soaked soybeans are steamed to obtain cooked soybeans, and then cooled to below 42°C. In this embodiment, a conventional NK steamer can be used as the steaming equipment, and steaming is carried out using a reduced-pressure steaming method. In this embodiment, the steaming pressure is preferably 0.08~0.12 MPa, preferably 0.10 MPa, and the steaming time is preferably 10~15 minutes. The cooked soybeans meet the conditions of being cooked but not mushy, and having plump grains but not undercooked. The cooling process of the cooked soybeans is preferably carried out using a blower-type cooling conveyor belt. The blower-type cooling conveyor belt can be equipped with a dust cover.

[0060] S3. Cleaning: After the normal production of the cooking process is completed, use the conventional cleaning method (rinsing with tap water) to wash away the cooked beans, bean skins and other substances remaining in the opening of the cooking pot and the feeding trough below the cooking pot.

[0061] S4. Spray antibacterial agent: After cleaning, spray the antibacterial agent from Example 4 onto the opening of the cooking pot and the inner wall of the feeding trough, and let it air dry naturally so that the clean equipment surface is in a high-salt environment before the next day's production, inhibiting the growth and reproduction of heat-resistant bacteria, in preparation for the next cooking.

[0062] S5. Mixing and Inoculation: Inoculate the cooled cooked beans with the inoculum and add flour. Mix the mixture evenly using a screw conveyor to obtain the mixture.

[0063] S6. Koji Making: The mixture is fed into a thick-layer, ventilated fermentation tank for koji making, thus producing Daqu (large koji). The thickness of the mixture in the fermentation tank is controlled at 30-40cm, and the koji making time is approximately 32-36 hours.

[0064] S7. Fermentation: The moisture content of the prepared Daqu (fermented starter culture) is tested and controlled to be 30%~35%. Then, brine is added to the Daqu and mixed evenly. The weight ratio of Daqu to brine is 1:1.5~2.5, and the concentration of the brine is 15~25g / 100mL, preferably 18~22g / 100mL. The Daqu is placed in a fermentation tank for fermentation. During fermentation, a re-oiling operation is performed every 10~15 days. After each re-oiling operation, the antibacterial agent described in Example 4 is sprayed onto the exposed inner wall of the fermentation tank to finally obtain natural oil. The weight ratio of Daqu to antibacterial agent sprayed is 1:0.1~1.

[0065] Example 8

[0066] This embodiment is largely the same as Embodiment 7, except that, in step S3, the antibacterial agent from Embodiment 2 is sprayed on the opening of the cooking pot and the inner wall of the feeding trough; and in step S7, the antibacterial agent from Embodiment 2 is sprayed on the inner wall of the fermenter.

[0067] Example 9

[0068] This embodiment is largely the same as Embodiment 7, except that, for step S3, the antibacterial agent from Embodiment 3 is sprayed on the opening of the cooking pot and the inner wall of the feeding trough; and for step S7, the antibacterial agent from Embodiment 3 is sprayed on the inner wall of the fermenter.

[0069] Comparative Example 2

[0070] The soy sauce brewing method in this comparative example specifically includes the following steps:

[0071] S1. Soaking soybeans: After removing impurities, put the soybeans into a soaking container and add water at 1.5 to 2 times their weight in soybeans. Soak for 4 to 8 hours. Preferably, the soybeans are non-GMO soybeans, and preferably, the soaking water is twice the weight of the soybeans.

[0072] S2. Steaming and Cooling: The soaked soybeans are steamed to obtain cooked soybeans, and then cooled to below 42°C. In this embodiment, a conventional NK steamer can be used as the steaming equipment, and steaming is carried out using a reduced-pressure steaming method. In this embodiment, the steaming pressure is preferably 0.08~0.12 MPa, preferably 0.10 MPa, and the steaming time is preferably 10~15 minutes. The cooked soybeans meet the conditions of being cooked but not mushy, and having plump grains but not undercooked. The cooling process of the cooked soybeans is preferably carried out using a blower-type cooling conveyor belt. The blower-type cooling conveyor belt can be equipped with a dust cover.

[0073] S3. Cleaning: After the normal production of the cooking process is completed, use the conventional cleaning method (rinsing with tap water) to wash away the cooked beans, bean skins and other substances remaining in the opening of the cooking pot and the feeding trough below the cooking pot.

[0074] S4. Mixing and Inoculation: Inoculate the cooled cooked beans with the inoculum and add flour. Mix the mixture evenly using a screw conveyor to obtain the mixture.

[0075] S5. Koji Making: The mixture is fed into a thick-layer, ventilated fermentation tank for koji making, thus producing Daqu (large koji). The thickness of the mixture in the fermentation tank is controlled at 30-40cm, and the koji making time is approximately 32-36 hours.

[0076] S6. Fermentation: The moisture content of the prepared Daqu (fermented starter culture) is tested and controlled to be 30%~35%. Then, brine is added to the Daqu and mixed evenly. The weight ratio of Daqu to brine is 1:1.5~2.5, and the concentration of the brine is 15~25g / 100mL, preferably 18~22g / 100mL. The Daqu is then placed in a fermentation tank for fermentation. During fermentation, a re-oiling operation is performed every 10~15 days to obtain natural oil.

[0077] Key indicators of the koji and natural oil produced using the equipment in Comparative Example 2 and Examples 7, 8, and 9 were tested, and the results are as follows:

[0078] Table 2 Physicochemical and microbiological indicators of comparative and example samples.

[0079]

[0080] Table 3. Physicochemical and microbiological properties of the natural oils obtained in the comparative examples and the actual examples.

[0081]

[0082] From the above comparative and example product data, it is clear that the examples have the following beneficial effects compared to the comparative examples:

[0083] 1) The reduced number of heat-resistant bacteria on the surface of the koji-making equipment also reduced the content of heat-resistant bacteria (calculated as Bacillus) in the koji, thus reducing the inhibitory effect of heat-resistant bacteria (calculated as Bacillus) on the target microbial group Aspergillus oryzae. This allowed Aspergillus oryzae to obtain sufficient nutrients for growth and reproduction, placing it in a dominant position and accumulating more enzymes for the fermentation stage (data shown in Table 2).

[0084] 2) The Daqu (fermentation starter culture) in the Example 1 had a lower spore count and higher protease activity (data shown in Table 2), providing favorable conditions for the fermentation stage. Firstly, the Daqu provided higher enzyme activity, allowing for thorough decomposition of substances in the raw materials throughout the fermentation process. Secondly, the Daqu contained a lower content of thermostable bacteria (calculated as Bacillus), reducing the introduction of thermostable bacteria (calculated as Bacillus) into the natural oil and preventing excessive consumption of nutrients in the raw materials during fermentation. In summary, the natural oil from the Example 1 outperformed the comparative example in all indicators (data shown in Table 3), and also improved the utilization rate of raw materials.

[0085] The above content is only a preferred embodiment of the present invention. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the concept of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A method of using an antibacterial agent, characterized in that, The antibacterial agent comprises the following substances in weight percentages: salt at a mass concentration of 18%–22%, edible gum at a mass concentration of 0.08%–0.12%, and the remainder being water, wherein the edible gum is xanthan gum; The method of use includes washing away the substances, including cooked beans and bean skins, remaining in the steaming and feeding equipment after the steaming and cooking process of soy sauce production using conventional cleaning methods; after cleaning, spraying the inner walls of the steaming and feeding equipment with the antibacterial agent and letting them air dry naturally for the next steaming and cooking use. It also includes the fermentation process in soy sauce production, natural sun-drying, and a re-oiling operation every 10 to 15 days according to process requirements; after the re-oiling is completed, the antibacterial agent is sprayed onto the exposed inner wall of the fermentation tank.

2. A soy sauce production process, characterized in that, Includes the following steps: S1. Soaking soybeans: After removing impurities from soybeans, put them into a soaking container, add water with 1.5 to 2 times the weight of the soybeans, and soak for 4 to 8 hours; S2. Steaming and Cooling: The soaked soybeans are steamed under reduced pressure at a pressure of 0.08 to 0.12 MPa for 10 to 15 minutes to obtain cooked soybeans. The cooked soybeans are then cooled to below 42°C. S3. Cleaning: Wash away any residue, including cooked beans and bean skins, remaining in the cooking and feeding equipment. S4. Spraying antibacterial agent: Spray an antibacterial agent on the inner wall of the cooking equipment and the feeding equipment, and let it air dry naturally for the next cooking use; the antibacterial agent includes the following substances by weight percentage: salt accounts for 18% to 22% of the mass concentration, edible gum accounts for 0.08% to 0.12% of the mass concentration, and the remainder is water, wherein the edible gum is xanthan gum; S5. Mixing and Inoculation: Inoculate the cooled cooked beans with the inoculum, add flour, and mix well to obtain the mixture; S6. Koji making: The mixture is fed into a thick-layer ventilated fermentation tank for koji making. The thickness of the mixture in the fermentation tank is controlled at 30-40cm, and the koji making time is 32-36 hours, thereby producing koji. S7. Fermentation: After controlling the moisture content of the Daqu to 30% to 35%, the Daqu is sent to a fermentation tank for fermentation. During the fermentation process, a re-oiling operation is performed every 10 to 15 days. After each re-oiling operation, the antibacterial agent is sprayed onto the exposed inner wall of the fermentation tank.

3. The soy sauce production process according to claim 2, characterized in that, In step S7, the weight ratio of the amount of Daqu (a type of starter culture) to the amount of the antibacterial agent sprayed is 1:0.1~1.

4. The soy sauce production process according to claim 3, characterized in that, In step S6, brine is added to the Daqu (a type of starter culture) and mixed evenly. The weight ratio of Daqu to brine is 1:1.5~2.5, and the concentration of brine is 15~25g / 100mL.

5. The soy sauce production process according to claim 4, characterized in that, The concentration of the saline solution is 18~22g / 100mL.

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