CN114045199B - Fruit vinegar fermentation process suitable for large-capacity fermentation tank - Google Patents

Abstract

The invention discloses a fruit vinegar fermentation process suitable for a large-capacity fermentation tank, and relates to the technical field of fermentation. The fruit vinegar fermentation process is characterized in that fruit wine and wine vinegar are adopted as fermentation substrates, acetic acid bacteria are inoculated and then fermentation is carried out until the target acidity and alcoholic strength are reached, the fermentation substrates have a certain acidic environment by controlling the acidity and alcoholic strength of the mixed fermentation substrates, the fermentation substrates can be quickly adapted to new environments after the acetic acid bacteria are inoculated, the fermentation process can be adapted to a large-volume fermentation tank with the volume of 20000L-28000L, and fruit vinegar products meeting the process requirements are obtained through fermentation, so that the fermentation of the large-volume fermentation tank is realized, and the process cost is remarkably reduced.

Description

Fruit vinegar fermentation process suitable for large-capacity fermentation tank

Technical Field

The invention relates to the technical field of fermentation, in particular to a fruit vinegar fermentation process suitable for a large-capacity fermentation tank.

Background

Along with the health idea of taking root in the heart of consumers, vinegar beverage with digestion promoting effect rapidly rises in the market, and the vinegar industry is developed at a high speed.

At present, the industrialized deep liquid fruit vinegar fermentation tank is a small-capacity fermentation tank with the common volume of 10t, the production efficiency and the productivity are low, the comprehensive energy consumption of water, electricity, steam and the like is high, the diatomite amount for single average filtration is large, and the sustainable development of enterprises is not facilitated. Based on the above, it is necessary to develop a large-capacity fermentation tank to meet the industrial production requirement. However, if the fermenter is simply enlarged, the fermentation is likely to fail, the fruit vinegar product cannot be obtained, and apple vinegar for beverage (GB/T30884-2014) is regulated that grains and byproducts thereof, sugar, alcohol, organic acid and other carbohydrate auxiliary materials cannot be used in the production process of apple vinegar for beverage.

In view of this, the invention is particularly directed to a process that uses only fruit or juice and its fermentation products as raw materials for a high capacity fruit vinegar fermenter.

Disclosure of Invention

The invention aims to provide a fruit vinegar fermentation process suitable for a large-capacity fermentation tank, and aims to realize fermentation by using the large-capacity fermentation tank to obtain a fruit vinegar product meeting process requirements.

The invention is realized in the following way:

in a first aspect, the present invention provides a fruit vinegar fermentation process suitable for use in a high capacity fermentor comprising: adopting fruit wine and wine vinegar as fermentation substrates, inoculating acetic acid bacteria, and fermenting until the acidity is 4.6-6.5g/100mL and the alcoholic strength is less than 0.5%vol;

wherein, the wine vinegar is the product of fruit vinegar fermentation failure or early fermentation completion, the fruit wine is the product of fruit or fruit juice after alcoholic fermentation, the acidity of the mixed fermentation substrate is 0.7-1.5g/100mL, and the alcoholic strength is 4.0-5.5%vol;

the volume of the fermentation tank adopted in the fermentation process is more than 20000L, and the fermentation tank filling liquid coefficient is 0.7-0.8.

In an alternative embodiment, the alcoholic strength of the wine and the vinegar is more than or equal to 0.5 percent vol, the acidity is less than or equal to 4.5g/100mL, and the alcoholic strength of the fruit wine is 8-10 percent vol;

preferably, the fermentation process employs a fermenter volume of 20000L-28000L.

In an alternative embodiment, the mass ratio of inoculum size to fermentation substrate of acetic acid bacteria is 10-16:100;

preferably, the acetic acid bacteria are derived from two different seed expanding culture tanks and expanding culture mediums, wherein one part adopts the alcohol content of the expanding culture mediums to be 5.0-5.5 percent vol, the soluble solid content is more than or equal to 4 percent, the alcohol content of the expanding culture mediums to be 4.0-4.5 percent vol, the soluble solid content is more than or equal to 3.5 percent, the expanding culture temperature is 30-35 ℃, and the acidity of the expanding culture is 1.5-2.5g/100mL.

In an alternative embodiment, the fermentation temperature is 30-35 ℃.

In an alternative embodiment, the fermentation process adopts a two-stage staged oxygen-introducing mode, the ventilation rate per hour is controlled to be 6.0-7.5:1 in terms of the volume ratio of air to the volume of fermented mash within the first 5-8 hours after the fermentation starts, and then the fermentation is finished according to the volume ratio of 7.0-9.5:1.

In an alternative embodiment, three stages of graded oxygen introducing modes are adopted in the fermentation process, the ventilation rate per hour is controlled to be 6.0-7.5:1 in terms of the volume ratio of air to the volume of fermented mash within the first 5-8 hours after the fermentation starts, then fermentation is carried out until the acidity value is greater than or equal to 5.0g/100mL according to the volume ratio of 7.0-9.5:1, and then fermentation is carried out until the fermentation is finished according to the volume ratio of 6.0-7.5:1.

In an alternative embodiment, the fermentation tank for fermentation comprises a tank body and a jacket cooling structure coated on the tank body, the jacket cooling structure is used for cooling by cooling water, and a polyurethane heat preservation layer is sleeved on the jacket cooling structure; the height-diameter ratio in the tank body is 1.0-1.8.

In an alternative embodiment, the top of the tank body is provided with an air outlet, and the air outlet is provided with a steam-water separator, and the steam-water separator is used for carrying out gas-liquid separation so as to return the liquid material into the tank body.

In an alternative embodiment, the tank is provided with a compressed air conduit, the compressed air conduit enters the tank from the top side wall of the tank and extends to the bottom of the tank, and the bottom of the tank is also provided with a self-priming impeller to disperse the gas output from the outlet of the compressed air conduit through the self-priming impeller.

In an alternative embodiment, a plurality of baffle plates are further installed on the inner wall of the tank body, the baffle plates are distributed in the tank body at intervals, and each baffle plate is attached to the inner wall of the tank body, so that vortex of materials is prevented by the baffle plates.

The invention has the following beneficial effects: the fruit wine and the wine vinegar are adopted as fermentation substrates, the fermentation is carried out until the target acidity and the alcohol degree are reached after the acetic acid bacteria are inoculated, the fermentation substrates have a certain acidic environment by controlling the acidity and the alcohol degree of the mixed fermentation substrates, the fermentation substrates can be quickly adapted to new environments after the acetic acid bacteria are inoculated, the fermentation substrates can be adapted to large-volume fermentation tanks with the volume of 20000L-28000L, the fruit vinegar products meeting the process requirements are obtained through fermentation, the fermentation of the large-volume fermentation tanks is further realized, and the process cost is remarkably reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a fermenter according to an embodiment of the present invention;

FIG. 2 is a top view of the fermenter of FIG. 1.

Description of main reference numerals: a 100-fermenter; 110-a tank; 120-jacket cooling structure; 111-exhaust port; 130-a compressed air conduit; 140-self-priming impeller; 150-a baffle plate; 160-supporting feet; 001-a temperature sensor interface; 002-bottom liquid level probe; 003-aseptic sampling valve interface; 004-viewing mirror viewing aperture; 005-spin CIP cleaning balls; 006-inspection manhole; 007-defoamer addition funnel; 008-automatic breathing apparatus; 009-high level probe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be noted that, if the terms "upper", "lower", "inner", "outer", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or the azimuth or the positional relationship in which the inventive product is conventionally put in use, it is merely for convenience of describing the present invention and simplifying the description, and it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus it should not be construed as limiting the present invention.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

In the prior art, a small fermentation tank is generally adopted for fermenting fruit vinegar, so that the production efficiency is low, and the cost is high. The yield of fruit vinegar is significantly reduced by using a large-volume fermenter, and thus, the fermentation of the large-volume fermenter is difficult to be applied industrially in a large scale, which is a problem for those skilled in the art.

The embodiment of the invention provides a fruit vinegar fermentation process suitable for a large-capacity fermentation tank, which comprises the following steps: the fruit wine and the wine vinegar are adopted as fermentation substrates, and fermentation is carried out after acetic acid bacteria are inoculated until the acidity is 4.6-6.5g/100mL and the alcoholic strength is less than 0.5%vol. By adopting the mixed fermentation substrate, the fermentation substrate has a certain acidic environment, is conducive to being capable of rapidly adapting to new environment after being inoculated with acetic acid bacteria, and is capable of adapting to a large-volume fermentation tank with the volume of 20000L-28000L, and the fruit vinegar product meeting the technological requirements is obtained through fermentation.

Specifically, the volume of the fermentation tank used in the fermentation process is more than 20000L, preferably 20000L-28000L, and the fermentation tank fluid coefficient is 0.7-0.8.

The wine vinegar refers to a product of fruit vinegar fermentation failure or early fermentation completion, and contains wine and vinegar, wherein the alcoholic strength of the wine vinegar is more than or equal to 0.5% vol; the acidity is less than or equal to 4.5g/100mL, the fruit wine is the product of fruit or fruit juice after alcoholic fermentation, and the alcoholic strength of the fruit wine is 8-10%vol. The acidity of the mixed fermentation substrate is 0.7-1.5g/100mL, and the alcoholic strength is 4.0-5.5%vol. The acidity and the alcoholicity of the mixed fermentation substrate are controlled in the above range, the too large and the too small acidity are unfavorable for fermentation, if the too large acidity possibly causes the inhibition effect of the high acidity environment on the activity of the strain, the growth and the reproduction of the strain are unfavorable, if the too small acidity is adopted, the adaptation period of the strain is prolonged, the fermentation period is correspondingly prolonged, the acid production is reduced at the same time, and the volatilization amount of the alcohol of the fruit wine is increased in the fermentation process.

Specifically, the acidity of the mixed fermentation substrate may be 0.7g/100mL, 0.8g/100mL, 0.9g/100mL, 1.0g/100mL, 1.1g/100mL, 1.2g/100mL, 1.3g/100mL, 1.4g/100mL, 1.5g/100mL, etc., or any value between the above adjacent acidity values; the alcoholic strength of the mixed fermentation substrate may be 4.0% vol, 4.1% vol, 4.2% vol, 4.3% vol, 4.4% vol, 4.5% vol, 4.6% vol, 4.7% vol, 4.8% vol, 4.9% vol, 5.0% vol, 5.1% vol, 5.2% vol, 5.3% vol, 5.4% vol, 5.5% vol, etc., or any value between the above adjacent alcoholic strengths.

The fermentation process provided by the embodiment of the invention does not need to add any grains, byproducts thereof, sugar, alcohol, organic acid and other carbohydrate auxiliary materials in the fermentation process, and does not need to add any fermentation processing promotion nutrition factors.

Further, the mass ratio of the inoculation amount of the acetic acid bacteria to the fermentation substrate is 10-16:100, and the fermentation temperature is 30-35 ℃. The inoculation amount of the acetic acid bacteria and the fermentation temperature are controlled within the above ranges, and if the inoculation amount of the acetic acid bacteria is too large or the fermentation temperature is too small, the fermentation yield of the fruit vinegar is not guaranteed. If the fermentation temperature is low, the bacterial growth is slow, the acetic acid fermentation efficiency is affected, the bacterial growth is promoted at a proper temperature, and the damage of acid to the bacterial is enhanced at an excessive temperature, so that the acid resistance is reduced.

Specifically, the mass ratio of the inoculation amount of the acetic acid bacteria to the fermentation substrate is 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, etc., and can be any value between the above adjacent mass ratios; the fermentation temperature may be 30℃at 31℃at 32℃at 33℃at 34℃at 35℃or any value between the above adjacent temperature values.

In some embodiments, the acetic acid bacteria are derived from two different seed expansion tanks and expansion media, wherein one part adopts the expansion media with the alcoholic strength of 5.0-5.5%vol, the soluble solid content is more than or equal to 4%, the other part adopts the expansion media with the alcoholic strength of 4.0-4.5%vol, the soluble solid content is more than or equal to 3.5%, the expansion temperature is 30-35 ℃, and the expansion transfer acidity is 1.5-2.5g/100mL. The acetic acid bacteria are derived from two different seed expansion culture tanks, so that the activity of the strains can be improved, and the reduction of the acid production rate and the reduction of the alcohol conversion rate in the fermentation process caused by the aging of a single strain in the passage process can be avoided.

In some embodiments, the fermentation process adopts a two-stage staged oxygen-introducing mode, and the ventilation rate per hour is controlled to be 6.0-7.5:1 in terms of the volume ratio of air to the volume of fermented mash within the first 5-8 hours after the fermentation starts, and then the fermentation is finished according to the volume ratio of 7.0-9.5:1.

In other embodiments, three stages of staged oxygen introduction modes are adopted in the fermentation process, the ventilation rate per hour is controlled to be 6.0-7.5:1 in terms of the volume ratio of air to the volume of fermented mash within the first 5-8 hours after the start of fermentation, then fermentation is carried out until the acidity value is greater than or equal to 5.0g/100mL according to the volume ratio of 7.0-9.5:1, and then fermentation is carried out until the end according to the volume ratio of 6.0-7.5:1. The three-stage grading oxygen-introducing mode is beneficial to saving energy consumption and preventing alcohol and acetic acid from being exerted due to excessive oxygen introduction.

The oxygen supply is adjusted according to the specific acidity value in the fermentation process, and the two-stage staged oxygen supply or the three-stage staged oxygen supply is selected. When the air quantity is low, the supply of thallus oxygen is insufficient, the dissolved oxygen is low, the acid production rate is low, and the concentration of fermentation final acid is low; the aeration rate is too high, the volatilization amount of alcohol and acetic acid is increased, and the fermentation final acid is also lower.

The following describes a large-volume fermenter 100 according to an embodiment of the present invention with reference to FIGS. 1 and 2:

the fermentation tank 100 provided by the embodiment of the invention comprises a tank body 110, a jacket cooling structure 120 coated on the tank body 110, a compressed air conduit 130, a self-priming impeller 140, a baffle plate 150 and the like.

The tank 110, bolts and pipes of the tank are made of SUS304 or more stainless steel materials, the volume is 20000L-28000L, the surface of the liner is 240 mesh polished, and the finish degree of the inner wall of the tank and the welded seam is less than or equal to Ra0.8.

Specifically, the jacket cooling structure 120 is used for cooling by cooling water, and a polyurethane heat insulation layer is further sleeved on the jacket cooling structure 120. Specifically, the jacket cooling structure 120 may be prepared by using a honeycomb type miller layer, and the jacket cooling structure may be cooled by ice water at a working pressure of 2-4bar and a temperature of about-4 ℃. The polyurethane heat-insulating layer can be made of foaming polyurethane, a 2B plate is wrapped outside, the thickness is 2.0mm, and the welding gap is polished by 180 meshes.

In some embodiments, an air outlet 111 is provided at the top of the tank 110, and a steam-water separator is provided on the air outlet 111, and the steam-water separator is used for performing gas-liquid separation, so as to return the liquid material into the tank 110, thereby improving the utilization rate of the raw materials. Through the steam-water separator designed on the exhaust port 111, the air bubbles of the fermented fruit vinegar are discharged into the steam-water separator along with the compressed air, the air is discharged out of the tank, and the liquid returns to the tank.

In some embodiments, the compressed air conduit 130 enters the tank 110 from the top side wall of the tank 110 and extends to the bottom of the tank 110, and a self-priming impeller 140 is further mounted at the bottom inside the tank 110 to disperse the gas output from the outlet of the compressed air conduit 130 by the self-priming impeller 140. In the fermentation process, sterile air enters the tank from the bottom, and can be uniformly dispersed in fermentation mash along with the rotation of the motor stirring impeller. Specifically, the self-priming impeller 140 is a stirring structure, the rotating speed is 900-1500r/min, a three-phase motor with the power of 15KW-22KW is adopted, a compressed air detection system is attached, and the air quantity is unstable and the alarm is given.

In some embodiments, a plurality of baffle plates 150 are further installed on the inner wall of the tank 110, the baffle plates 150 are distributed in the tank 110 at intervals, and each baffle plate 150 is attached to the inner wall of the tank 110, so that the baffle plates 150 prevent the material from generating vortex, thereby effectively improving fermentation and shortening fermentation time. Because the liquid loading amount is large, the turbulence degree of the materials can be effectively increased by the tank wall flow baffle 150, vortex generation is reduced, the material stirring efficiency and the oxygen dissolution degree are improved, the fluid movement is changed into axial and radial flow, the material rolling degree is increased, and fermentation of the fermentation liquid is more uniform.

In some embodiments, the volume of the fermentation tank is 20t and above, the height-diameter ratio in the tank body is 1.0-1.8, the height-diameter ratio is too large, the up-down mixing degree of materials is small, and the dissolved oxygen amount of the upper layer fermentation mash is small; the height-diameter ratio is too small, and the amount of dissolved oxygen in the mash becomes smaller along with the increase of the distance from the axis because the sterile air enters the tank from the middle part of the cone bottom.

In some embodiments, four sets of height-adjustable support feet 160 are mounted to the bottom of the tank 110 to accommodate different height conditions. The tank body 110 can be further provided with a fermentation compressed air volume monitoring system, and the fermentation compressed air volume monitoring system can automatically monitor the air volume below a set value and alarm; the temperature sensor interface 001, the liquid level detection interface (comprising a bottom liquid level probe 002 and a high liquid level probe 009), the sterile sampling valve interface 003, the dissolved oxygen instrument interface and the like can be further arranged, so that the temperature sensor, the liquid level detection mechanism, the dissolved oxygen instrument and other equipment can be conveniently installed for parameter monitoring.

In some embodiments, an automatic breathing device 008 may be further disposed on the top of the tank 110, and the negative pressure prevention technology is utilized; a sight glass viewing hole 004 can be arranged, and the condition in the tank can be observed through a sight glass lamp; two sets of rotary CIP cleaning balls 005 can be arranged for cleaning the tank body; a DN500 manhole 006, defoamer addition funnel 007, etc. may also be provided.

The features and capabilities of the present invention are described in further detail below in connection with the examples.

Example 1

The embodiment provides a fruit vinegar fermentation process suitable for a large-capacity fermentation tank, which adopts the fermentation tanks in fig. 1 and 2 for fermentation, and comprises the following steps:

the method adopts wine vinegar with the alcoholic strength of about 0.6 percent vol and fruit wine with the alcoholic strength of about 9.1 percent vol as mixed fermentation substrates, and controls the acidity of the mixed fermentation substrates to be about 1.0g/100mL and the alcoholic strength to be about 5.0 percent vol. Inoculating acetic acid bacteria for fermentation, wherein acetic acid bacteria seeds are derived from two different seed expansion culture tanks (one part adopts an expansion culture medium with the alcohol content of 5.0 percent vol, a soluble solid with the alcohol content of 4.0 percent vol, the other part adopts an expansion culture medium with the alcohol content of 4.7 percent vol, a soluble solid with the alcohol content of 3.7 percent, the expansion culture temperature is 35 ℃, the expansion culture transfer acidity is 2.5g/100 mL), and the mass ratio of acetic acid bacteria liquid of the two seed expansion culture tanks is 1:1, controlling the mass ratio of acetic acid bacteria to the mixed fermentation substrate to be 12:100, the volume of a fermentation tank to be 20000L, and the liquid filling coefficient to be 0.8.

In the fermentation process, the fermentation temperature is controlled to be about 33 ℃, a three-stage sectional ventilation mode is adopted, the ventilation rate per hour is controlled to be 6.0:1 in the volume ratio of air volume to fermented mash liquid in the first 6 hours after the fermentation starts, then fermentation is carried out until the acidity value is more than or equal to 5.0g/100mL according to the volume ratio of 9.0:1, and then fermentation is carried out until the fermentation is finished according to the volume ratio of 6.0:1. The fermentation is completed with the alcohol content controlled to be 0.5% vol or less.

Example 2

The present embodiment provides a fruit vinegar fermentation process suitable for a large-capacity fermenter, which adopts the process route in fig. 1, and differs from that of embodiment 1 only in that: the fermentation process adopts a two-stage staged oxygen-introducing mode, the ventilation rate per hour is controlled to be 7.0:1 in the volume ratio of air to fermented mash in the first 6 hours after the fermentation starts, and then the fermentation is finished according to the volume ratio of 8.0:1.

Comparative example 1

The comparative example provides a fruit vinegar fermentation process, the volume structure of the fermentation tank is the same as that of the embodiment 1, and the specific process is only different from the embodiment 1 in that: the fermentation substrate adopts single fruit wine, the acidity is about 0.2g/100mL, and the alcoholic strength is about 6.0%vol.

Comparative example 2

The comparative example provides a fruit vinegar fermentation process, the volume structure of the fermentation tank is the same as that of the example 2, and the specific process is different from the example 2 only in that: acetic acid strain seeds are sourced from the same seed expanding culture tank, the alcohol content of the expanding culture medium is 5.1% vol, and the soluble solid content is 4.7%.

Comparative example 3

This comparative example provides a fruit vinegar fermentation process which differs from example 1 only in that: the fermenter does not comprise a baffle plate on the inner wall of the fermenter.

The result shows that the fermentation acidity is not increased to 3.4g/100mL, the residual alcohol degree is 2.6g/100mL, and acetic acid bacteria cannot continuously utilize alcohol in fermentation liquor to produce acetic acid.

Test example 1

The fermentation duration, end acidity, average acid production, and alcohol conversion parameters were tested in example 1 and comparative example 1 and the results are shown in table 1:

TABLE 1 comparison of fermentation data for different fermentation substrates

Project	Example 1	Comparative example 1
			Fermentation time length, h	20-24	34-38
Finish acidity, g/100mL	5.76-6.07	5.38-5.55
			Acid production at the same time, g/100mL	0.1976-0.2371	0.1208-0.1455
Alcohol conversion rate%	104.32-108.81	93.52-97.28
			Success rate of fermentation%	≥99.5	≥50
Further preparing fruit vinegar beverage	Good flavor and stability	Flavor is general and unstable

Test example 2

The fermentation duration, end acidity, average acid production, and alcohol conversion parameters were tested in example 2 and comparative example 2 and the results are shown in table 2:

TABLE 2 comparison of single species and double species fermentation data

Project	Example 2	Comparative example 2
			Fermentation time length, h	23-26	28-33
EndingAcidity, g/100mL	5.65-5.98	5.44-5.68
			Acid production at the same time, g/100mL	0.1989-0.2289	0.1589-0.1737
Alcohol conversion rate%	102.22-106.13	101.21-103.52

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

1. A fruit vinegar fermentation process suitable for a high-capacity fermentation tank, which is characterized by comprising the following steps: adopting fruit wine and wine vinegar as fermentation substrates, inoculating acetic acid bacteria, and fermenting until the acidity is 4.6-6.5g/100mL and the alcoholic strength is less than 0.5%vol;

wherein the wine vinegar is the product of fruit vinegar fermentation failure or early fermentation completion, the fruit wine is the product of fruit or fruit juice after alcoholic fermentation, the acidity of the mixed fermentation substrate is 0.7-1.5g/100mL, and the alcoholic strength is 4.0-5.5%vol;

the volume of a fermentation tank adopted in the fermentation process is more than 20000L, and the fermentation tank filling liquid coefficient is 0.7-0.8;

the alcoholic strength of the wine vinegar is more than or equal to 0.5 percent vol, the acidity is less than or equal to 4.5g/100mL, and the alcoholic strength of the fruit wine is 8-10 percent vol;

the mass ratio of the inoculation amount of the acetic acid bacteria to the fermentation substrate is 10-16:100; the acetic acid bacteria originate from two different seed expansion culture tanks, and correspond to two different seed expansion culture medium materials for expanding culture of bacteria, wherein one part adopts the expansion culture medium material with the alcohol content of 5.0-5.5 percent vol, the soluble solid content is more than or equal to 4 percent, the other part adopts the expansion culture medium material with the alcohol content of 4.0-4.5 percent vol, the soluble solid content is more than or equal to 3.5 percent, and the mass ratio of the acetic acid bacteria liquid of the two seed expansion culture tanks is 1:1, a step of;

the fermentation process adopts a two-stage grading oxygen-introducing mode, the ventilation rate per hour is controlled to be 6.0-7.5:1 in the volume ratio of air to fermented mash in the first 5-8 hours after the fermentation starts, and then the fermentation is finished according to the volume ratio of 7.0-9.5:1; or, three-stage grading oxygen introducing mode is adopted in the fermentation process, the ventilation rate per hour is controlled to be 6.0-7.5:1 in terms of air volume to fermented mash volume ratio within the first 5-8 hours after the fermentation starts, then fermentation is carried out until the acidity value is greater than or equal to 5.0g/100mL according to the volume ratio of 7.0-9.5:1, and then fermentation is carried out until the fermentation is finished according to the volume ratio of 6.0-7.5:1;

the fermentation tank for fermentation comprises a tank body and a jacket cooling structure coated on the tank body, wherein the jacket cooling structure is used for cooling by cooling water, and a polyurethane heat-insulating layer is sleeved on the jacket cooling structure; the height-diameter ratio in the tank body is 1.0-1.8;

the tank body is provided with a compressed air conduit, the compressed air conduit enters the tank body from the side wall of the top of the tank body and extends to the bottom of the tank body, and the bottom of the tank body is also provided with a self-priming impeller so as to disperse the gas output from the outlet of the compressed air conduit through the self-priming impeller;

the inner wall of the tank body is also provided with a plurality of flow baffle plates, the flow baffle plates are distributed in the tank body at intervals, and each flow baffle plate is attached to the inner wall of the tank body so as to prevent the materials from generating vortex through the flow baffle plates.

2. The fruit vinegar fermentation process according to claim 1, wherein the fermentation process employs a fermentation tank having a volume of 20000L-28000L.

3. The fruit vinegar fermentation process according to claim 1, wherein the fermentation temperature is 30-35 ℃.

4. The fruit vinegar fermentation process according to claim 1, wherein an air outlet is provided at the top of the tank body, and a steam-water separator is provided on the air outlet, and the steam-water separator is used for performing gas-liquid separation to return the liquid material into the tank body.