Grain low-temperature soaking and curing pretreatment solid-state fermentation process

Abstract

The application provides a kind of grain low-temperature soaking, curing pretreatment solid fermentation process, it relates to grain fermentation technical field, it is characterized in that, comprising the following steps: step 1, whole grain screening;Step 2, countercurrent low-temperature soaking: whole grain is placed in multistage countercurrent soaking system, with water temperature 5 to 10 ℃ clean water is soaked and treated;Step 3, moderate curing treatment: after soaking and draining, grain is sent into zoned temperature control steaming equipment, and curing treatment is carried out;Step 4, cooling inoculation: after curing, grain is first cooled by heat exchange, then cooled rapidly, and then fermentation strain is inoculated;Step 5, solid fermentation: after inoculation, grain is placed in forced ventilation fermentation environment, and solid state is carried out;Step 6, low-temperature drying: after fermentation, material is low-temperature dried, and fermented grain product is obtained.The application has the advantages that: whole grain solid fermentation with high safety, short cycle and low contamination rate is realized, and is suitable for the fermentation deep processing of various miscellaneous grains.

Description

Technical Field

[0001] This invention relates to the field of grain fermentation technology, and in particular to a solid-state fermentation process for low-temperature soaking and ripening pretreatment of grains. Background Technology

[0002] Solid-state fermentation of grains is an important approach for the deep processing of miscellaneous grains and the development of functional foods. Existing pretreatment processes mainly include three categories: one is to directly ferment the grains after crushing them and adding water; the second is to soak them at room temperature and then steam them until fully cooked before fermentation; and the third is to soak the raw grains for a short time and then directly ferment them for a long time.

[0003] However, the following defects exist in practical application: Incomplete removal of harmful substances from the grain skin: Saponins, tannins, and pesticide residues on the grain skin are the main sources of bitterness and safety risks in the product. After crushing, starch dissolution hinders saponin diffusion, resulting in a low removal rate; during whole-grain soaking at room temperature, harmful substances are solidified within the living tissue due to grain germination and metabolism; High risk of germination and mold during soaking: The water temperature for soaking at room temperature is usually higher than 12℃, which activates the grain's respiration and germination process, leading to germ germination, starch degradation, and structural loosening; at the same time, microorganisms in the natural water body proliferate in large quantities at room temperature, causing mold and off-odors; Fermentation efficiency and permeability cannot be balanced: Direct fermentation of raw materials results in a slow fermentation period of more than 20 hours due to the crystalline state of starch, with a total cycle exceeding 70 hours; if the grain is completely cooked, the grains become mushy, stick together, and clump severely, resulting in loss of permeability of the material layer, the formation of an anaerobic environment inside, and a high rate of contamination by miscellaneous bacteria.

[0004] Therefore, there is an urgent need for a low-temperature soaking and maturation pretreatment solid-state fermentation process for grains that can effectively remove harmful substances from the surface, prevent germination during soaking, improve fermentation efficiency, and ensure stable fermentation, in order to solve the above-mentioned technical problems. Summary of the Invention

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A low-temperature soaking, cooking, and pretreatment solid-state fermentation process for grain includes the following steps: Step 1, grain screening: Select whole grains, remove impurities, broken grains, and moldy grains, maintain the integrity of the grain shape, and the broken grains ≤1%;

[0007] Step 2, Countercurrent Low-Temperature Soaking: Place the whole grains in a multi-stage countercurrent soaking system and soak them in clean water at a temperature of 5 to 10°C. The total soaking time is 5 to 10 hours. Fresh low-temperature water is added to the final soaking tank, and the first soaking tank uses the soaking liquid overflowing from the second stage. High-concentration soaking wastewater is discharged after the soaking is completed.

[0008] Step 3, Moderate Cooking Treatment: After soaking and draining, the grains are sent to a zoned temperature-controlled steaming equipment and cooked under normal or low pressure steam environment. The cooking endpoint is controlled to be 70-80% cooked, that is, the outer tissue of the grains is fully cooked, the center retains a hard core, and the grains do not break or stick together.

[0009] Step 4, Cooling and Inoculation: The cooked grain is first pre-cooled by heat exchange, then rapidly cooled to 30 to 35°C by vacuum cooling, and then inoculated with fermentation bacteria in a clean environment;

[0010] Step 5, Solid-state fermentation: Place the inoculated grain in a forced-ventilation fermentation environment with a temperature of 28 to 32°C and a relative humidity of 60% to 70% for solid-state fermentation for 48 to 60 hours. During the fermentation period, turn the material intermittently according to the temperature change.

[0011] Step 6, Low-temperature drying: After fermentation, the material is dried at a low temperature of 40 to 50°C until the moisture content is ≤10%, thus obtaining the fermented grain product.

[0012] As an improvement, the multi-stage countercurrent soaking system in step 2 consists of 2 to 4 tanks connected in series. The fresh grains and the soaking liquid flow in opposite directions. The high-concentration soaking wastewater discharged from the first-stage tank is treated by an air flotation defoaming device to remove saponin foam before entering the wastewater treatment system.

[0013] As an improvement, after the low-temperature soaking in step 2, a surface micro-damage treatment step is also included: low-pressure friction treatment or ultrasonic vibration treatment with a roller spacing greater than the grain diameter is used to create micro-cracks or micropores in the grain seed coat, while the grain remains intact and unbroken.

[0014] As an improvement, in step 3, the zoned temperature-controlled steaming equipment is set up with a preheating zone, a strong steaming zone, and a steaming zone in sequence along the material travel direction. The temperature and steam flow rate of each zone are independently adjustable. The determination of the cooking endpoint is based on the real-time detection value of the online dielectric constant sensor. When the dielectric characteristic value falls into the preset "seven or eight parts cooked" calibration range, the conveyor belt travel speed or steam supply is automatically adjusted.

[0015] As an improvement, the heat exchange pre-cooling in step 4 is specifically as follows: the grain with a temperature of 85 to 100°C after cooking is passed into the heat exchange silo, and the low-temperature soaking wastewater of 5 to 10°C discharged in step 2 is used as the cooling medium for indirect heat exchange, so that the temperature of the grain is reduced to 40 to 50°C before being sent into the vacuum cooler.

[0016] As an improvement, the grain raw material is selected from at least one of quinoa, oats, barley, buckwheat, millet, and sorghum.

[0017] A grain low-temperature soaking, cooking pretreatment solid fermentation equipment system includes, along the material flow direction, the following components in sequence: a pretreatment unit including a vibrating screen and a color sorter, used to output grain with a whole grain rate of ≥99%;

[0018] Low-temperature countercurrent immersion unit: includes 2 to 4 series-connected conical-bottom immersion tanks with cooling jackets, with overflow pipes between each tank, the last tank connected to a fresh cold water supply pipe, and the first tank connected to a high-concentration wastewater discharge pipe;

[0019] Surface micro-damage treatment unit: includes a low-pressure rubber roller friction machine or an ultrasonic vibration groove, used to form micro-cracks in the grain seed coat;

[0020] Zoned temperature control steaming unit: including a tunnel-type mesh belt steamer with a preheating zone, a strong steaming zone, and a humidification zone. Each zone's steam pipeline is independently equipped with a proportional regulating valve. An online dielectric constant sensor is installed at the equipment outlet. This sensor is electrically connected to the frequency converter that controls the mesh belt speed and the steam regulating valve.

[0021] Heat exchange precooling unit: includes a temporary storage silo with an indirect heat exchange jacket, the cooling medium inlet of which is connected to the high-concentration wastewater discharge pipe of the low-temperature countercurrent soaking unit through pipelines and pumps;

[0022] Vacuum cooling unit: including vacuum cooling tank and vacuum system, used to rapidly cool the pre-cooled grain to the inoculation temperature;

[0023] Clean inoculation unit: includes a closed inoculation auger under a Class 100 laminar flow hood, with bacterial liquid atomizing nozzles inside the auger;

[0024] Solid-state fermentation unit: including multi-layer disc fermentation bed or box-type ventilated fermentation bed, equipped with air conditioning purification unit and low-frequency rake loosening device;

[0025] Low-temperature drying unit: including heat pump dehumidification type multi-layer belt dryer, whose hot air temperature control range is 40 to 50℃.

[0026] As an improvement, the wastewater discharge pipe of the first tank of the low-temperature countercurrent soaking unit is connected to an air flotation defoaming device downstream, and the outlet of the air flotation defoaming device is connected to an anaerobic fermentation system or a conventional sewage treatment network.

[0027] As an improvement, the control system of the zoned temperature-controlled steaming unit has a pre-stored formula library of cooking parameters for at least three grains: quinoa, oats, and sorghum. The operation interface has a grain variety selection button, and after selection, the system automatically calls up the corresponding zoned temperature setting value and the mesh belt reference speed.

[0028] As an improvement, the low-frequency rake loosener in the solid-state fermentation unit has a rake tooth rotation speed of 0.5 to 2 r / h, and the minimum distance between the tip of the rake tooth and the bottom surface of the fermentation bed is not less than 5 cm, so as to avoid crushing the whole grain during the turning process.

[0029] The beneficial effects of this invention are as follows: by setting a low-temperature countercurrent soaking process, saponins, tannins and pesticide residues are continuously diffused and dissolved from the intact seed coat into the low-temperature water body, while inhibiting the germination metabolism and microbial proliferation of the grains. This results in a significant increase in the removal rate of harmful substances on the seed coat, a pure and non-bitter taste in the product, and enhanced food safety. It can also be used for a variety of grains.

[0030] By setting up zoned temperature-controlled steaming equipment and online dielectric constant sensor closed-loop control, precise control of the degree of ripening and stable maintenance of the critical state are achieved, shortening the overall fermentation cycle and improving product quality. Attached Figure Description

[0031] Figure 1 This is a flowchart of a solid-state fermentation process for low-temperature soaking, ripening, and pretreatment of grains according to the present invention;

[0032] Figure 2 A system block diagram of an equipment for applying the present invention, which involves low-temperature soaking, ripening, and solid-state fermentation of grain. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0034] It should be noted that the terms "first" and "second" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0035] like Figure 1As shown, a solid-state fermentation process for low-temperature soaking and ripening pretreatment of grain includes the following steps: Step 1, Grain screening: Select whole grains, remove impurities, broken grains, and moldy grains, maintaining the integrity of the grain shape, with broken grains ≤1%; Step 2, Countercurrent low-temperature soaking: Place the whole grains in a multi-stage countercurrent soaking system and soak them in clean water at a temperature of 5 to 10°C for a total soaking time of 5 to 10 hours. The final soaking tank is replenished with fresh low-temperature water, while the first-stage soaking tank utilizes the overflow soaking liquid from the second-stage tank. High-concentration soaking wastewater is discharged after soaking; Step 3, Moderate ripening treatment: Send the soaked and drained grains into a zoned temperature-controlled steaming device for ripening under normal or low-pressure steam conditions. The maturation process is as follows: Step 4, Cooling and Inoculation: The matured grain is pre-cooled by heat exchange, then rapidly cooled to 30-35°C under vacuum, and then inoculated with fermentation bacteria in a clean environment. Step 5, Solid-State Fermentation: The inoculated grain is placed in a forced-ventilation fermentation environment at 28-32°C and 60-70% relative humidity for 48-60 hours, with the material being turned intermittently according to temperature changes during fermentation. Step 6, Low-Temperature Drying: After fermentation, the material is dried at 40-50°C until the moisture content is ≤10%, yielding the fermented grain product. This combined approach of forced ventilation and intermittent turning fully utilizes the natural permeability of the whole grain layer, avoiding grain breakage or localized anaerobic conditions caused by improper turning frequency.

[0036] In step 2, the multi-stage countercurrent soaking system consists of 2 to 4 tanks connected in series. The fresh grain and the soaking liquid flow in opposite directions. The high-concentration soaking wastewater discharged from the first-stage tank is treated with an air flotation defoaming device to remove saponin foam before entering the wastewater treatment system. After the low-temperature soaking in step 2, a surface micro-damage treatment step is also included: low-pressure friction treatment or ultrasonic vibration treatment is used with a roller spacing larger than the grain diameter to create micro-cracks or micropores in the grain seed coat, while the grain remains intact and unbroken. In step 3, the zoned temperature-controlled steaming equipment is set up with a preheating zone, a strong steaming zone, and a steaming zone along the material's direction of travel. The temperature and steam flow rate of each zone are independently adjustable. The determination of the cooking endpoint is based on the real-time detection value of the online dielectric constant sensor. When the dielectric characteristic value falls into the preset "70-80% cooked" calibration range, the conveyor belt speed or steam supply is automatically adjusted. The heat exchange precooling in step 4 specifically involves: introducing the cooked grain, with a temperature of 85 to 100°C, into the heat exchange silo; using the low-temperature soaking wastewater (5 to 10°C) discharged in step 2 as a cooling medium for indirect heat exchange; and then sending the grain to a vacuum cooler after the temperature has dropped to 40 to 50°C. The grain raw material is selected from at least one of quinoa, oats, barley, buckwheat, millet, and sorghum. By setting up a built-in raw material formula library and a one-click recall function in the control system, the system automatically configures differentiated cooking parameters for different grain varieties such as quinoa, oats, and sorghum, achieving the effects of shortened production changeover and commissioning time, and enhanced equipment versatility and industrial compatibility.

[0037] like Figure 2As shown, a grain low-temperature soaking, ripening, and pretreatment solid-state fermentation equipment system comprises, along the material flow direction, the following components: a pretreatment unit, including a vibrating screen and a color sorter, for outputting grains with a whole grain rate ≥99%; a low-temperature countercurrent soaking unit, including 2 to 4 series-connected conical-bottom soaking tanks with cooling jackets, with overflow pipes between each tank, the final tank connected to a fresh cold water supply pipe, and the first tank connected to a high-concentration wastewater discharge pipe; a surface micro-damage treatment unit, including a low-pressure rubber roller friction machine or an ultrasonic vibration tank, for forming micro-cracks in the grain seed coat; and a zoned temperature-controlled steaming unit, including a tunnel-type mesh belt steamer with a preheating zone, a strong steaming zone, and a humidification zone, with each zone's steam pipeline independently equipped with a proportional regulating valve, and an online dielectric constant sensor installed at the equipment outlet. The sensor is electrically connected to the frequency converter controlling the belt speed and the steam regulating valve; the heat exchange precooling unit includes a temporary storage silo with an indirect heat exchange jacket, the cooling medium inlet of which is connected to the high-concentration wastewater discharge pipe of the low-temperature countercurrent soaking unit through pipelines and pumps; the vacuum cooling unit includes a vacuum cooling tank and a vacuum system for rapidly cooling the precooled grain to the inoculation temperature; the clean inoculation unit includes a sealed inoculation auger under a Class 100 laminar flow hood, with bacterial liquid atomizing nozzles inside the auger; the solid-state fermentation unit includes a multi-layer disc fermentation bed or a box-type ventilated fermentation bed, equipped with an air conditioning purification unit and a low-frequency rake-type loosening device; the low-temperature drying unit includes a heat pump dehumidification type multi-layer belt dryer with a hot air temperature control range of 40 to 50°C.

[0038] Downstream of the wastewater discharge pipe of the first-stage tank of the low-temperature countercurrent soaking unit is an air flotation defoaming device, the outlet of which is connected to an anaerobic fermentation system or a conventional sewage treatment network. The control system of the zoned temperature-controlled steaming unit has a pre-stored formula library containing cooking parameters for at least three grains: quinoa, oats, and sorghum. The operating interface has a grain selection button; after selection, the system automatically calls the corresponding zone temperature setpoint and conveyor belt reference speed. In the solid-state fermentation unit, the low-frequency rake loosener rotates at 0.5 to 2 r / h, with a minimum distance of 5 cm between the rake tooth tip and the bottom of the fermentation bed to avoid crushing whole grains during turning. By setting up a heat pump dehumidification type low-temperature dryer and controlling the hot air temperature at 40–50℃, rapid dehydration and shaping of the fermented material in a low-temperature environment is achieved, resulting in maximum retention of flavor active substances, stable final product moisture content, and reduced drying energy consumption.

[0039] Example: Whole quinoa grains soaked at low temperature - moderately matured solid-state fermentation

[0040] (1) Raw material grain processing: Select white quinoa produced in the current year, remove light impurities and stones by multi-stage air separation and vibrating screen, and remove discolored grains, immature grains and moldy grains by high-definition color sorter to obtain clean quinoa grains with a grain-whole rate of ≥99%, without any crushing process.

[0041] (2) Low-temperature countercurrent soaking pretreatment: Whole quinoa grains were fed into a three-stage series countercurrent soaking system. Each soaking tank was equipped with a refrigeration jacket, and the soaking water temperature was precisely controlled at 8±1℃ by a chiller unit. Fresh quinoa entered the first-stage tank, and the soaking liquid flowed countercurrently through each stage, with fresh cold water replenished from the third-stage tank. The total soaking time was 8 hours, during which the soaking liquid between stages was naturally replenished through overflow pipes. The high-concentration soaking wastewater discharged from the first-stage tank was treated by an air flotation defoaming device before being discharged. After soaking, the saponin dissolution rate of quinoa epidermis reached 87.2%, and the grains showed no sprouting or mold.

[0042] (3) Surface micro-damage treatment: After soaking and draining, quinoa is passed through a low-pressure rubber roller friction machine. The distance between the rubber rollers is adjusted to 2.0 mm (greater than the quinoa particle size of 1.5 to 1.8 mm). Under the action of the difference in linear speed of the roller surface, micro-cracks are generated in the seed coat, and the whole grain remains intact with a breakage rate of <0.3%.

[0043] (4) Zoned temperature control for moderate ripening: Spread the processed quinoa evenly on the tunnel-type mesh belt steamer with a thickness of 8cm. The equipment is set up in the following order along the direction of travel: Preheating zone: temperature 85℃, time 5 minutes; Strong steaming zone: 100℃ saturated steam is introduced, time 12 minutes; Soaking zone: direct steam is turned off, and the temperature is maintained at 90~95℃ by using residual heat, time 3 minutes.

[0044] An online dielectric constant sensor is installed at the equipment outlet to monitor the dielectric characteristics of the material in real time. When the detected value falls within the preset "70-80% ripe" calibration range for quinoa, the system automatically fine-tunes the conveyor belt speed. After ripening, the quinoa grains are fully cooked on the outside, while retaining a hard core of about 1 / 3 of their diameter in the center, resulting in intact, unbroken, and non-sticky grains.

[0045] (5) After cooling and inoculation, the quinoa temperature is approximately 96°C. It is first placed in a heat exchange pre-cooling silo, where the 8°C low-temperature wastewater discharged from the soaking unit is used for indirect heat exchange through a jacket to lower the grain temperature to 48°C. Then, it is sent to a vacuum cooling tank, where it is rapidly cooled to 32°C under a vacuum of -0.095MPa. The cooled quinoa is then placed in a Class 100 laminar flow purification inoculation auger, where activated brewing yeast solution is sprayed in at an inoculation rate of 0.5% (w / w) and mixed evenly.

[0046] (6) Solid-state fermentation: The inoculated quinoa was placed into a multi-layer disc fermentation bed with a layer thickness of 45cm. The air conditioning purification unit was turned on to control the fermentation environment temperature at 30±1℃ and the relative humidity at 65±5%. The forced ventilation system circulated the temperature- and humidity-controlled air from the bottom of the material layer upwards. During the fermentation process, a low-frequency rake loosener intermittently turned the material at a speed of 1r / h, with the rake teeth spaced 8cm from the bottom surface. The fermentation time was 54 hours, during which the material temperature was monitored and did not exceed 34℃.

[0047] (7) After the low-temperature drying and fermentation is completed, the material is sent to a heat pump dehumidification multi-layer belt dryer, the hot air temperature is set to 45℃, and the moisture content is dried to 9.5% to obtain fermented quinoa product.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid-state fermentation process for low-temperature soaking, ripening, and pretreatment of grains, characterized in that, Includes the following steps: Step 1, Whole Grain Screening: Select whole grains, remove impurities, broken grains and moldy grains, maintain the integrity of the grain shape, and keep broken grains ≤1%; Step 2, Countercurrent Low-Temperature Soaking: Place the whole grains in a multi-stage countercurrent soaking system and soak them in clean water at a temperature of 5 to 10°C. The total soaking time is 5 to 10 hours. Fresh low-temperature water is added to the final soaking tank, and the first soaking tank uses the soaking liquid overflowing from the second stage. High-concentration soaking wastewater is discharged after the soaking is completed. Step 3, Moderate Cooking Treatment: After soaking and draining, the grains are sent to a zoned temperature-controlled steaming equipment and cooked under normal or low pressure steam environment. The cooking endpoint is controlled to be 70-80% cooked, that is, the outer tissue of the grains is fully cooked, the center retains a hard core, and the grains do not break or stick together. Step 4, Cooling and Inoculation: The cooked grain is first pre-cooled by heat exchange, then rapidly cooled to 30 to 35°C by vacuum cooling, and then inoculated with fermentation bacteria in a clean environment; Step 5, Solid-state fermentation: Place the inoculated grain in a forced-ventilation fermentation environment with a temperature of 28 to 32°C and a relative humidity of 60% to 70% for solid-state fermentation for 48 to 60 hours. During the fermentation period, turn the material intermittently according to the temperature change. Step 6, Low-temperature drying: After fermentation, the material is dried at a low temperature of 40 to 50°C until the moisture content is ≤10%, thus obtaining the fermented grain product.

2. The solid-state fermentation process for low-temperature soaking and ripening pretreatment of grains according to claim 1, characterized in that, In step 2, the multi-stage countercurrent soaking system consists of 2 to 4 tanks connected in series. The fresh grains and the soaking liquid flow in opposite directions. The high-concentration soaking wastewater discharged from the first-stage tank is treated by an air flotation defoaming device to remove saponin foam before entering the wastewater treatment system.

3. The solid-state fermentation process for low-temperature soaking and ripening pretreatment of grains according to claim 1, characterized in that, After the low-temperature soaking in step 2, the surface micro-damage treatment step is also included: low-pressure friction treatment or ultrasonic vibration treatment with a roller spacing greater than the grain diameter is used to create micro-cracks or micropores in the grain seed coat, while the grain remains intact and does not break.

4. The solid-state fermentation process for low-temperature soaking and ripening pretreatment of grains according to claim 1, characterized in that, In step 3, the zoned temperature-controlled steaming equipment is set up with a preheating zone, a strong steaming zone, and a steaming zone in sequence along the material travel direction. The temperature and steam flow rate of each zone are independently adjustable. The determination of the cooking endpoint is based on the real-time detection value of the online dielectric constant sensor. When the dielectric characteristic value falls into the preset "70-80% cooked" calibration range, the conveyor belt travel speed or steam supply is automatically adjusted.

5. The solid-state fermentation process for low-temperature soaking and ripening pretreatment of grains according to claim 1, characterized in that, The heat exchange precooling in step 4 specifically involves: feeding the cooked grain, which has a temperature of 85 to 100°C, into the heat exchange silo, and using the low-temperature soaking wastewater (5 to 10°C) discharged in step 2 as a cooling medium for indirect heat exchange, so that the grain temperature is reduced to 40 to 50°C before being sent into the vacuum cooler.

6. The solid-state fermentation process for low-temperature soaking and ripening pretreatment of grain according to claim 1, characterized in that, The grain raw materials are selected from at least one of quinoa, oats, barley, buckwheat, millet, and sorghum.

7. A solid-state fermentation equipment system for implementing the low-temperature soaking, ripening, and pretreatment of grains as described in any one of claims 1 to 6, characterized in that, Along the material flow direction, it includes: a pre-processing unit, which includes a vibrating screen and a color sorter, used to output grain with a whole grain rate of ≥99%; Low-temperature countercurrent immersion unit: includes 2 to 4 series-connected conical-bottom immersion tanks with cooling jackets, with overflow pipes between each tank, the last tank connected to a fresh cold water supply pipe, and the first tank connected to a high-concentration wastewater discharge pipe; Surface micro-damage treatment unit: includes a low-pressure rubber roller friction machine or an ultrasonic vibration groove, used to form micro-cracks in the grain seed coat; Zoned temperature control steaming unit: including a tunnel-type mesh belt steamer with a preheating zone, a strong steaming zone, and a humidification zone. Each zone's steam pipeline is independently equipped with a proportional regulating valve. An online dielectric constant sensor is installed at the equipment outlet. This sensor is electrically connected to the frequency converter that controls the mesh belt speed and the steam regulating valve. Heat exchange precooling unit: includes a temporary storage silo with an indirect heat exchange jacket, the cooling medium inlet of which is connected to the high-concentration wastewater discharge pipe of the low-temperature countercurrent soaking unit through pipelines and pumps; Vacuum cooling unit: including vacuum cooling tank and vacuum system, used to rapidly cool the pre-cooled grain to the inoculation temperature; Clean inoculation unit: includes a closed inoculation auger under a Class 100 laminar flow hood, with bacterial liquid atomizing nozzles inside the auger; Solid-state fermentation unit: including multi-layer disc fermentation bed or box-type ventilated fermentation bed, equipped with air conditioning purification unit and low-frequency rake loosening device; Low-temperature drying unit: including heat pump dehumidification type multi-layer belt dryer, whose hot air temperature control range is 40 to 50℃.

8. A solid-state fermentation equipment system for low-temperature soaking and ripening pretreatment of grain according to claim 7, characterized in that, Downstream of the wastewater discharge pipe of the primary tank of the low-temperature countercurrent soaking unit is an air flotation defoaming device, and the outlet of the air flotation defoaming device is connected to an anaerobic fermentation system or a conventional sewage treatment network.

9. A solid-state fermentation equipment system for low-temperature soaking and ripening pretreatment of grain according to claim 7, characterized in that, The control system of the zoned temperature-controlled steaming unit has a pre-stored formula library of cooking parameters for at least three grains: quinoa, oats, and sorghum. The operation interface has a grain variety selection button. After selection, the system automatically calls up the corresponding zoned temperature setting value and the conveyor belt reference speed.

10. A solid-state fermentation equipment system for low-temperature soaking and ripening pretreatment of grain according to claim 7, characterized in that, The low-frequency rake loosener in the solid-state fermentation unit rotates at a speed of 0.5 to 2 r / h, and the minimum distance between the tip of the rake tooth and the bottom of the fermentation bed is not less than 5 cm, so as to avoid crushing the whole grain during the turning process.

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