Multi-category vegetable circulation fermentation system and fermentation method

Abstract

A circulating fermentation system and fermentation method for multiple types of vegetables belong to the technical field of fermented food preparation devices. The fermentation system includes: a fermentation tank and a mixing tank. There are multiple fermentation tanks, and a discharge pipe is provided at the bottom of the fermentation tank. The discharge pipe is connected to a liquid discharge pipe. A filter tube is provided in each fermentation tank. The upper end of the filter tube passes upward through the top of the fermentation tank. The filter tube is arranged to move in the vertical direction. During fermentation, the lower end of the filter tube is inserted into the discharge pipe, and the filter mesh is located inside the fermentation tank. There is at least one mixing tank, and the liquid discharge pipes are all connected to the mixing tank. A stirring shaft is provided inside the mixing tank, and the mixing tank is connected to the upper end of the filter tube through a reflux pipe. The fermentation method includes the following steps: S1: feeding; S2: initial fermentation; S3: circulating fermentation liquid; S4: repeating step S3. This solution helps to accelerate the maturation of vegetables, and meets the requirements of more diverse strains and flavors while also meeting the requirements of convenient discharge.

Description

Technical Field

[0001] The present invention belongs to the technical field of fermented food preparation devices, and in particular relates to a circulating fermentation system and a fermentation method for multiple types of vegetables. Background Art

[0002] Kimchi refers to vegetables that have been fermented for long-term storage. There are many types of kimchi, including pickled ginger, cowpea, cabbage, etc. In order to increase the fermentation speed, the existing fermentation process is usually a secondary return-to-jar fermentation process, that is, it is first fermented by salting, and then the vegetables are put back into the kimchi jar for return-to-jar fermentation after desalting. The vegetables lose a lot of nutrients after salting. Even if the flavor of the fermented product is enriched by adding carbon sources through return-to-jar fermentation, it is still difficult to achieve the ideal effect, resulting in a weak fermentation flavor and more nutrients in the vegetables. On the other hand, in order to facilitate the collection of materials and to judge the fermentation end point of different vegetables, single-variety vegetables are usually fermented separately. This will result in a single flavor and weak complex flavor of the fermented vegetables, making it difficult to achieve the excellent flavor of traditional kimchi. Summary of the Invention

[0003] In order to address the deficiencies of the existing technology, the present invention provides a multi-category vegetable recycling fermentation system and fermentation method. The fermentation liquid is recycled and mixed, which helps to accelerate the maturation of vegetables and shorten the fermentation time. While meeting the requirements of richer strains and flavors, it also meets the requirements of convenient discharge.

[0004] In order to achieve the purpose of the present invention, the following scheme is proposed:

[0005] A multi-category vegetable circulating fermentation system comprises a fermentation tank and a mixing tank.

[0006] There are multiple fermentation tanks, which are used to ferment different types of vegetables. A discharge pipe is provided at the bottom of the fermentation tank, and a liquid discharge pipe is connected to the discharge pipe. A valve is provided on the liquid discharge pipe, and a cover is provided at the bottom of the discharge pipe. A filter tube is provided in each fermentation tank, and a filter mesh is provided on the side wall. The upper end of the filter tube passes upward through the top of the fermentation tank, and the outer wall of the lower end of the filter tube matches the inner wall of the discharge pipe. The filter tube is movable in the vertical direction. During fermentation, the lower end of the filter tube is inserted into the discharge pipe, and the filter mesh is located inside the fermentation tank.

[0007] There is at least one mixing tank, and the liquid outlet pipes are connected to the mixing tank. A stirring shaft is provided inside the mixing tank, and the stirring shaft is driven by the fermentation liquid discharged into the mixing tank through the liquid outlet pipe. The mixing tank is connected to the upper end of the filter tube through a reflux pipe, which is used to inject the mixed fermentation liquid in the mixing tank into the fermentation tank. A water pump is provided on the reflux pipe.

[0008] A multi-category vegetable cyclic fermentation method is implemented using the multi-category vegetable cyclic fermentation system described above, comprising the following steps:

[0009] S1: Feeding: adding a single type of vegetables into multiple fermentation tanks;

[0010] S2: Initial fermentation: adding water, salt and sugar into the fermentation tank respectively and fermenting for a predetermined time;

[0011] S3: Circulating the fermentation liquid, discharging the fermentation liquid inside each fermentation tank into the mixing tank through the liquid outlet pipe for mixing, and using a water pump to inject the mixed fermentation liquid into the fermentation tank again through the reflux pipe and the filter pipe. The fermentation tank drainage and immersion are carried out simultaneously;

[0012] S4: Repeat step S3, each cycle lasting 5 to 10 minutes, at least twice a day.

[0013] The beneficial effects of the present invention are:

[0014] The compound fermentation of multiple vegetables has rich strains and flavors. The fermentation system can realize the simultaneous circulation fermentation of multiple vegetables. The fermentation liquids from different fermentation tanks are concentrated in the liquid circulation tank for mixing. After mixing, they are respectively pumped into fermentation tanks of different vegetable varieties, giving a single vegetable a complex fermentation flavor.

[0015] Discharging in separate tanks is easy to control. Different raw materials can be fermented in separate tanks. Different liquid circulation and exhaust times can be set according to the maturity of different ingredients. This is also convenient for later discharging and packaging, eliminating the need for manual sorting or difficult discharging during mixed fermentation.

[0016] The fermentation liquid can be recycled to accelerate the ripening of fresh vegetables. The liquid from the previous round of fermentation can be used as the mother water for inoculation and fermentation in the next round, accelerating the fermentation of fresh vegetables and quickly forming the kimchi flavor.

[0017] The mixed vegetable fermentation liquid has a wider range of uses. The mixed fermentation liquid can be stored in a mixing tank, which is convenient for taking out the mixed vegetable fermentation liquid. The mixed fermentation liquid can be used alone for other products to enhance the fermentation flavor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present invention.

[0019] Figure 1 Shown is a schematic diagram of the overall structure of this application.

[0020] Figure 2 A cross-sectional view showing a preferred configuration of a mixing tank.

[0021] Figure 3 A schematic diagram of the external structure of the fermentation tank is shown.

[0022] Figure 4 A cross-sectional view of a fermenter is shown.

[0023] Figure 5 A cross-sectional view of the end of the pressure relief tube is shown.

[0024] Markings in the figure: fermenter 1, discharge pipe 11, liquid discharge pipe 12, cover plate 13, main pipe 14, filter pipe 2, disc 21, mixing tank 3, reflux pipe 31, premixing bin 32, support frame 33, stirring shaft 4, blade 41, stirring rod 42, water pump 5, pressure relief pipe 6, exhaust hole 61, annular water tank 62, valve body 7, counterweight 71, annular groove 72. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0026] Example 1, as Figure 1 As shown, a multi-category vegetable circulating fermentation system includes: a fermentation tank 1 and a mixing tank 3.

[0027] Specifically, such as Figure 1 、 Figure 3 、 Figure 4 As shown, there are multiple fermentation tanks 1, which are used to ferment different types of vegetables. The feeding port of the fermentation tank 1 is provided with a top, and the feeding port is provided with a sealing cover. A discharge pipe 11 is provided at the bottom of the fermentation tank 1. The side wall of the discharge pipe 11 is connected to a liquid discharge pipe 12, and a valve is provided on the liquid discharge pipe 12. A cover plate 13 is provided at the bottom of the discharge pipe 11. A filter tube 2 is provided in the fermentation tank 1, and a filter mesh is provided on its side wall. The upper end of the filter tube 2 passes upward through the top of the fermentation tank 1, and the outer wall of the lower end of the filter tube 2 matches the inner wall of the discharge pipe 11 to prevent impurities and vegetables from falling from the gap between the filter tube 2 and the discharge pipe 11. The filter tube 2 is arranged to move in the vertical direction. Specifically, a telescopic device can be provided at the top of the fermentation tank 1 to drive the filter tube 2 to rise and fall. The telescopic device is a cylinder or a linear motor. During fermentation, the lower end of the filter tube 2 is inserted into the discharge pipe 11, and the filter mesh is located inside the fermentation tank 1.

[0028] Specifically, such as Figure 1 、 Figure 2As shown, there is at least one mixing tank 3, and each liquid outlet pipe 12 is connected to the mixing tank 3. The mixing tank 3 is used to collect the fermentation liquid discharged from each fermentation tank 1. The mixing tank 3 is provided with a stirring shaft 4 inside, which is used to stir the fermentation liquid entering the mixing tank 3 to ensure thorough mixing. The stirring shaft 4 is driven by the fermentation liquid discharged into the mixing tank 3 by the liquid outlet pipe 12. The mixing tank 3 is connected to the upper end of the filter tube 2 via a return pipe 31, which is used to inject the mixed fermentation liquid in the mixing tank 3 into the fermentation tank 1. The upper end of the filter tube 2 and the return pipe 31 are connected by a hose to accommodate the up and down movement of the filter tube 2. A water pump 5 is provided on the return pipe to deliver the mixed fermentation liquid in the mixing tank 3 to the fermentation tank 1. Specifically, the height of the top surface of the mixing tank 3 is lower than the height of the bottom surface of the fermentation tank 1.

[0029] Preferably, Figure 1 As shown, the ends of the liquid outlet pipes 12 are connected to the same main pipe 14, which is connected to the mixing tank 3. This structure can preliminarily mix the fermentation liquids discharged from each fermentation tank 1 inside the main pipe 14, thereby improving the uniform mixing effect.

[0030] In the early stage of fermentation, multiple fermentation tanks 1 are used to ferment different types of vegetables, including sauerkraut, beans, radish, ginger and peppers. During the fermentation process, the valve on the liquid outlet pipe 12 is in a closed state to prevent the liquid inside each fermentation tank 1 from flowing out.

[0031] After the predetermined fermentation time, the valve is opened, and the fermentation liquid inside the fermentation tank 1 will automatically seep into the filter tube 2 and enter the discharge pipe 11, and then flow into the mixing tank 3 through the discharge pipe 12 and mix inside the mixing tank 3. In the process of discharging the fermentation liquid, the filter tube 2 can prevent impurities and vegetables from entering the mixing tank 3, avoiding blockage of the water pump 5 and various pipes; then, the mixed fermentation liquid inside the mixing tank 3 is injected into the upper end of the filter tube 2 through the water pump 5, and the mixed fermentation liquid seeps out from the filter mesh on the side wall of the filter tube 2, and then enters the fermentation tank 1. Because the lower end of the filter tube 2 is inserted into the discharge pipe 11, the filter tube 2 just passes through the vegetables inside the fermentation tank 1, so that the mesh on the side wall of the filter tube 2 can be used to more quickly inject the mixed fermentation liquid into the gaps of vegetables at different heights; the above process can be carried out multiple times during the fermentation period, and various vegetables can be fermented with the mixed fermentation liquid, which effectively increases the strains, improves the flavor of the vegetables and the fermentation efficiency; and different types of vegetables are still fermented in a single tank, which is convenient for separate material extraction.

[0032] After the fermentation is completed, the liquid inside the fermentation tank 1 is first discharged into the mixing tank 3, and used as the mother water for the next fermentation for inoculation fermentation, which accelerates the fermentation of fresh vegetables and quickly forms a sour and refreshing flavor. At the same time, it enhances the fermentation flavor of subsequent vegetables and makes the fermentation liquid reach the flavor of traditional old brine; after the fermentation liquid is drained, the cover 13 is opened, and the filter tube 2 is moved upward to separate the lower end of the filter tube 2 from the discharge pipe 11, and then the fermented vegetables can be discharged through the discharge pipe 11.

[0033] Preferably, a plurality of mixing tanks 3 are provided in series to increase the number of mixing times and improve the mixing uniformity of the fermentation liquid.

[0034] Preferably, Figure 4 As shown, a disc 21 is coaxially provided on the outside of the lower end of the filter tube 2. When the bottom surface of the disc 21 abuts against the bottom surface of the fermentation tank 1, the lower end of the filter tube 2 is inserted into the discharge pipe 11. The provision of the disc 21 can improve the purpose of isolating the discharge pipe 11 and the fermentation tank 1, further preventing vegetables and impurities from entering the liquid discharge pipe 12, and preventing the liquid discharge pipe 12 from being blocked. During discharge, the rising disc 21 is utilized to push the surrounding vegetables to prevent the accumulated vegetables from forming an "arch bridge" structure after the fermentation liquid is discharged, thereby affecting the smooth discharge. The rising disc 21 can effectively achieve the purpose of breaking the arch and improve the smoothness of vegetable discharge. Further preferably, the top surface of the disc 21 is a conical surface to prevent vegetables from accumulating on the top surface of the disc 21.

[0035] Preferably, Figure 2 As shown, a premixing chamber 32 is coaxially provided at the upper end of the mixing tank 3 and is connected thereto. The upper end of the stirring shaft 4 passes through the top of the premixing chamber 32. A support frame 33 is provided at the connection portion between the premixing chamber 32 and the mixing tank 3. The middle section of the stirring shaft 4 passes through the support frame 33. A stirring rod 42 is provided at the lower end of the stirring shaft 4. The stirring rod 42 is located inside the mixing tank 3. A plurality of blades 41 are provided in a circumferential array along the upper end of the stirring shaft 4. The fermentation liquid discharged from the fermentation tank 1 enters the premixing chamber 32 along a tangential direction, thereby utilizing the impact force of the fermentation liquid to push the blades 41 to drive the stirring shaft 4 to rotate, and then utilizing the stirring rod 42 to stir and mix the fermentation liquid inside the mixing tank 3. The fermentation liquid entering the premixing chamber 32 will also be retained in the premixing chamber 32 for a period of time under the drive of the blades 41, and then flow into the mixing tank 3. During the retention period, the fermentation liquid will also be mixed with each other inside the premixing chamber 32, thereby improving the final mixing effect.

[0036] Specifically, the fermentation liquid entering the premixing chamber 32 can be injected into the premixing chamber 32 separately through each liquid outlet pipe 12, and the liquid outlet pipes 12 are all arranged along the tangential direction of the premixing chamber 32, or can be injected uniformly through the main pipe 14, and the main pipe 14 is arranged along the tangential direction of the premixing chamber 32.

[0037] As a preferred structure, in order to enable the fermentation liquid entering the premixing chamber 32 to smoothly drive the stirring shaft 4 to rotate, the projected height of the blade 41 on the vertical plane can be set to be greater than the height of the stirring rod 42, so as to increase the impact surface of the fermentation liquid on the blade 41 and reduce the rotational resistance of the stirring rod 42.

[0038] Preferably, during the fermentation process, the filter mesh at the upper end of the side wall of the filter tube 2 is located above the fermentation liquid surface and the vegetables, and the diameter of the mesh at the upper end is larger than the diameter of the mesh at the lower end of the filter tube 2. During the process of adding the mixed fermentation liquid into the fermentation tank 1, due to the blockage of some of the mesh at the lower end of the filter tube 2 by the external vegetables, the mixed fermentation liquid cannot be discharged smoothly, and the filling pressure needs to be increased to inject the mixed fermentation liquid. With the above arrangement, even if the mesh at the lower end of the filter tube 2 is blocked, the mixed fermentation liquid can be discharged smoothly into the fermentation tank 1 through the mesh at the upper end of the filter tube 2 with a larger diameter. After the mesh at the lower end of the filter tube 2 is blocked, the pressure inside the filter tube 2 will increase. Since the diameter of the mesh at the upper end of the filter tube 2 is larger than the diameter of the mesh at the lower end, the mixed fermentation liquid discharged from the mesh at the upper end of the filter tube 2 will be discharged in a jet state, thereby increasing the spray area of ​​the mixed fermentation liquid and preventing yeast growth on the material from causing blooming, which leads to an abnormal kimchi flavor. Specifically, the inner diameter of the mesh at the upper end of the filter tube 2 is set to 2mm-5mm. Because the mesh at the upper end of the filter tube 2 has a certain height position, it can prevent impurities from entering the interior of the filter tube 2 during the process of discharging the fermentation liquid.

[0039] Preferably, Figure 3 、 Figure 5As shown, a pressure relief pipe 6 is provided at the top of the fermentation tank 1. The end of the pressure relief pipe 6 is vertically facing upward, and an exhaust hole 61 is provided on the side wall of the end of the pressure relief pipe 6. An annular water tank 62 is provided on the outside of the end of the pressure relief pipe 6 corresponding to the lower side of the exhaust hole 61. Liquid is contained in the annular water tank 62, and the liquid level of the liquid is higher than the exhaust hole 61. A valve body 7 is slidingly provided inside the pressure relief pipe 6. When the valve body 7 is in the lowest position, the side wall of the valve body 7 covers the exhaust hole 61. When gas is generated due to vegetable fermentation inside the fermentation tank 1, the gas will enter the pressure relief pipe 6. When the air pressure inside the fermentation tank 1 and the pressure relief pipe 6 reaches a predetermined value, the gas will push the valve body 7 to move upward until the valve body 7 opens the exhaust hole 61, and the gas can be smoothly discharged into the liquid in the annular water tank 62 and generate bubbles, so that workers can observe the exhaust situation and then judge the growth of microorganisms. During the fermentation process, the gas production usually increases from small to large and finally becomes smaller. The larger the gas production, the more vigorous the microorganism growth and the better the activity. Because during the exhaust process, the air pressure inside the pressure relief pipe 6 is greater than the external environmental pressure, and can overcome the weight of the valve body 7 and eventually open the exhaust hole 61, the exhausted gas also has sufficient pressure to discharge the liquid that originally entered the outer end of the exhaust hole 61 and prevent the liquid from entering the pressure relief pipe 6 during the exhaust process. When the pressure inside the pressure relief pipe 6 decreases, the valve body 7 will automatically fall under the action of gravity and close the exhaust hole 61 again.

[0040] Preferably, in order to prevent gas from being discharged from the upper end of the filter tube 2, an electric-controlled valve can be provided at the upper end of the filter tube 2, and the electric-controlled valve can be provided outside the fermentation tank 1. During the fermentation process, the electric-controlled valve is in a closed state, and the electric-controlled valve is opened only during the circulation of the fermentation liquid. In addition, by providing the electric-controlled valve, the amount of mixed fermentation liquid entering the fermentation tank 1 can be controlled. After a predetermined amount of mixed fermentation liquid is injected into the fermentation tank 1, the corresponding electric-controlled valve can be closed.

[0041] Preferably, Figure 5 As shown, a replaceable counterweight 71 is provided on the top of the valve body 7, so that the weight of the counterweight 71 can be adjusted according to different vegetables to adapt to different gas production during fermentation of different vegetables. The outer diameter of the counterweight 71 is larger than the inner diameter of the pressure relief pipe 6. When the bottom surface of the counterweight 71 contacts the top surface of the pressure relief pipe 6, the valve body 7 is in the lowest position.

[0042] More preferably, Figure 5As shown, the outer wall of the valve body 7 is provided with multiple layers of annular grooves 72. When the valve body 7 is in the lowest position, there is at least one layer of annular grooves 72 below the corresponding exhaust hole 61. When the exhaust hole 61 is open, there is at least one layer of annular grooves 72 above the corresponding exhaust hole 61. When the valve body 7 is in the lowest position, the residual liquid in the annular groove 72 below the exhaust hole 61 can be used to form an annular sealing structure between the valve body 7 and the inner wall of the pressure relief pipe 6 to prevent liquid from entering the pressure relief pipe 6. When the exhaust hole 61 is open, the residual liquid in the annular groove 72 above the exhaust hole 61 can also be used to form an annular sealing structure between the valve body 7 and the inner wall of the pressure relief pipe 6 to prevent gas from being discharged from the upper end of the pressure relief pipe 6 and affecting the generation of bubbles, thereby ensuring the accuracy of bubble observation.

[0043] Example 2, a multi-category vegetable cyclic fermentation method, implemented using the multi-category vegetable cyclic fermentation system described in Example 1, comprises the following steps:

[0044] S1: feeding, respectively feeding a single type of vegetables into multiple fermentation tanks 1;

[0045] S2: Initial fermentation: adding water, salt and sugar into the fermentation tank 1 respectively and fermenting for a predetermined time. The initial fermentation time is usually 20 to 40 days. Depending on the type of vegetables, it can be fermented for 25 days, 30 days or 35 days, which is convenient for management.

[0046] S3: Circulating the fermentation liquid. The fermentation liquid in each fermentation tank 1 is discharged into the mixing tank 3 through the liquid outlet pipe 12 for mixing. The mixed fermentation liquid is then injected back into the fermentation tank 1 through the return pipe 31 and the filter pipe 2 by the water pump 5. The drainage and immersion of the fermentation tank 1 are carried out simultaneously.

[0047] S4: Repeat step S3, each cycle lasting 5 to 10 minutes, at least twice a day.

[0048] Table 1: The relative contents of characteristic flavor compounds in different fermentation raw materials obtained by gas chromatography-mass spectrometry (GC-MS) are listed;

[0049]

[0050]

[0051]

[0052] Table 2 shows the sensory evaluation results of different fermented vegetables. The evaluation process was conducted by 10 professional sensory evaluators who received sensory training. They conducted a double-blind sensory evaluation and then calculated the average value.

[0053]

[0054] Volatile flavor components of single-fermented radish, mustard greens, chili peppers, and cowpeas, as well as mixed-fermented vegetables using this protocol, were analyzed and summarized. The results are shown in Table 1. The total number and relative total content of characteristic flavor compounds in the mixed-fermented vegetables, categorized by esters, alcohols, aldehydes, ketones, acids, and other classes, are superior to those in any single-fermented brew. This demonstrates that the mixed-fermentation process can combine the excellent flavors of various vegetables, consistent with the sensory evaluation results in Table 2. Furthermore, the mixed-fermented vegetables reduce some of the strong, pungent flavors of the single-fermented samples, such as the reduced toluene content, effectively improving the appearance of unusual flavors in the brewed products.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to be the only one or to limit the present invention. It should be understood by those skilled in the art that various changes or equivalent replacements made to the present invention without departing from the scope of the present invention are within the scope of protection of the present invention.

Claims

1. A multi-category vegetable cyclic fermentation method, characterized in that: Includes: Includes the following steps: S1: feeding, respectively feeding a single type of vegetables into a plurality of fermentation tanks (1), the number of fermentation tanks (1), respectively used for fermenting different types of vegetables, the bottom of the fermentation tank (1) is provided with a discharge pipe (11), the discharge pipe (11) is connected to a liquid discharge pipe (12), the liquid discharge pipe (12) is provided with a valve, the bottom of the discharge pipe (11) is provided with a cover plate (13), the fermentation tank (1) is provided with a filter tube (2), the side wall of which is provided with a filter mesh, the upper end of the filter tube (2) passes through the top of the fermentation tank (1), the outer wall of the lower end of the filter tube (2) matches the inner wall of the discharge pipe (11), the filter tube (2) is arranged to move in the vertical direction, during the fermentation period, the lower end of the filter tube (2) is inserted into the discharge pipe (11), and the filter mesh is located inside the fermentation tank (1); S2: initial fermentation, adding water, salt and sugar into the fermentation tank (1) respectively, and fermenting for a predetermined time; S3: circulating the fermentation liquid, discharging the fermentation liquid in each fermentation tank (1) into the mixing tank (3) through the liquid outlet pipe (12) for mixing, the liquid outlet pipe (12) is connected to the mixing tank (3), a stirring shaft (4) is provided inside the mixing tank (3), the stirring shaft (4) is driven by the fermentation liquid discharged into the mixing tank (3) through the liquid outlet pipe (12), the mixing tank (3) is connected to the upper end of the filter pipe (2) through the return pipe (31), and is used to inject the mixed fermentation liquid in the mixing tank (3) into the fermentation tank (1), the return pipe is provided with a water pump (5), and the mixed fermentation liquid is injected into the fermentation tank (1) again through the return pipe (31) and the filter pipe (2) by the water pump (5), and the fermentation tank (1) is discharged and soaked simultaneously; S4: Repeat step S3, each cycle lasting 5 to 10 minutes, at least twice a day.

2. The multi-category vegetable cyclic fermentation method according to claim 1, characterized in that: A disc (21) is coaxially provided on the outside of the lower end of the filter tube (2). When the bottom surface of the disc (21) abuts against the bottom surface of the fermentation tank (1), the lower end of the filter tube (2) is inserted into the discharge pipe (11).

3. The multi-category vegetable cyclic fermentation method according to claim 1, characterized in that: The ends of the liquid outlet pipes (12) are connected to the same main pipe (14), and the main pipe (14) is connected to the mixing tank (3).

4. The multi-category vegetable cyclic fermentation method according to claim 1 or 3, characterized in that: The upper end of the mixing tank (3) is coaxially and connected with a premixing chamber (32), the upper end of the stirring shaft (4) is passed through the top of the premixing chamber (32), a support frame (33) is provided at the connection portion between the premixing chamber (32) and the mixing tank (3), the middle section of the stirring shaft (4) passes through the support frame (33), the lower end of the stirring shaft (4) is provided with a stirring rod (42), the stirring rod (42) is located inside the mixing tank (3), the upper end of the stirring shaft (4) is provided with a plurality of blades (41) along a circumferential array, and the fermentation liquid discharged from the fermentation tank (1) enters the premixing chamber (32) along a tangential direction.

5. The multi-category vegetable recycling fermentation system according to claim 1, characterized in that: The upper end of the filter tube (2) is connected to the return pipe (31) via a hose.

6. The multi-category vegetable cyclic fermentation method according to claim 1, characterized in that: During the fermentation process, the filter mesh at the upper end of the side wall of the filter tube (2) is located above the fermentation liquid surface and the vegetables, and the diameter of the upper end mesh is larger than the diameter of the lower end mesh of the filter tube (2).

7. The multi-category vegetable cyclic fermentation method according to claim 1, characterized in that: A pressure relief pipe (6) is provided at the top of the fermentation tank (1), the end of the pressure relief pipe (6) is vertically upward, and a vent hole (61) is provided on the side wall of the end of the pressure relief pipe (6). An annular water tank (62) is provided on the outer side of the end of the pressure relief pipe (6) below the vent hole (61), and the annular water tank (62) is filled with liquid, the liquid level of which is higher than the vent hole (61). A valve body (7) is provided inside the pressure relief pipe (6) for sliding. When the valve body (7) is at the lowest position, the side wall of the valve body (7) covers the vent hole (61).

8. The multi-category vegetable cyclic fermentation method according to claim 7, characterized in that: A replaceable counterweight (71) is provided on the top of the valve body (7). The outer diameter of the counterweight (71) is larger than the inner diameter of the pressure relief pipe (6). When the bottom surface of the counterweight (71) contacts the top surface of the pressure relief pipe (6), the valve body (7) is at the lowest position.

9. The multi-category vegetable cyclic fermentation method according to claim 7, characterized in that: The outer wall of the valve body (7) is provided with multiple layers of annular grooves (72). When the valve body (7) is at the lowest position, there is at least one layer of annular groove (72) below the corresponding exhaust hole (61). When the exhaust hole (61) is open, there is at least one layer of annular groove (72) above the corresponding exhaust hole (61).

10. The multi-category vegetable cyclic fermentation method according to claim 7, characterized in that: There is at least one mixing tank (3).

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