CN116076589A - Method for efficiently producing puer ripe tea through time sequence control fermentation - Google Patents

Abstract

The invention belongs to the technical field of tea fermentation, and discloses a method for efficiently producing puer ripe tea by time sequence control fermentation, which comprises the following steps: (S1) preparing aspergillus strain to obtain aspergillus niger (Aspergillus niger) and aspergillus oryzae (Aspergillus oryzae) spore liquid; (S2) preparing a sterilized fermentation tank, and putting the pretreated sun-cured raw tea into the fermentation tank; (S3) inoculating Aspergillus oryzae spore liquid, starting fermentation, and when Aspergillus oryzae is planted in the leaves, inoculating Aspergillus niger spore liquid, and continuing fermentation; and (S4) ending fermentation and placing in a tank to obtain the puer ripe tea product. The invention controls fermentation (especially accurate time sequence control fermentation) by microorganism time sequence, which not only improves the quality of puer ripe tea obviously, but also shortens the fermentation period effectively and improves the production efficiency. In addition, the time sequence control technology established by the invention is also applicable to the production of tea products by liquid fermentation.

Description

Method for efficiently producing puer ripe tea through time sequence control fermentation

Technical Field

The invention belongs to the technical field of tea fermentation, and particularly relates to a method for efficiently producing puer ripe tea by time sequence control fermentation.

Background

Pu 'er tea is a special geographic marking product in Yunnan, and is classified into Pu' er raw tea and Pu 'er ripe tea according to the processing technology and quality characteristics of Pu' er tea. The traditional puer ripe tea is prepared by taking special large leaf seed sun-dried tea of Yunnan as a raw material and manually piling and fermenting. The artificial pile fermentation has the problems of long period, low production efficiency, uneven fermentation, unstable quality, heavy pile taste, uneven products, difficult food sanitation reaching standards and the like.

In recent years, researchers have made various improvements and innovations in the puer ripe tea fermentation technology: (1) In the fermentation form, the traditional ground-connected fermentation is gradually changed into the ground-separated basket fermentation of a clean workshop, so that the sanitary problem of the puer ripe tea fermentation is solved to a certain extent, but in order to further realize controllable fermentation and improve the product quality, the puer ripe tea fermentation tank is utilized for fermentation to form a very innovative fermentation form, the temperature and humidity of the fermentation process can be controlled in a fully-closed state, the mechanical pile turning process is completed, the safety and sanitation of puer ripe tea products are ensured, the labor cost is reduced, the production period is greatly shortened, and the method is a future development trend of puer ripe tea fermentation technology. (2) In the fermentation mode, from the traditional natural fermentation, namely fermentation depending on the Pu 'er ripe tea pile fermentation environment or the existing microbial community on the surface of the tea, the fermentation is gradually changed into fermentation by manually adding beneficial microorganisms, and the type and community change of the microorganisms in the fermentation process are focused, for example, the microbial analysis of the pile fermentation process in paper "multi-group study of microbial community and protein in Pu' er tea fermentation process" finds that the main microorganisms in the early stage of fermentation are Aspergillus niger and Enterobacter; the middle fermentation period is blue-like bacteria and thermophilic bacteria; the later fermentation period is bacillus; however, the paper "microbial community structure and variation in Pu ' er tea solid state fermentation" finds that Aspergillus niger is the dominant strain in the early fermentation stage, and Bacillus and Arxula adeninivorans are the main dominant strains in the late fermentation stage of Pu ' er tea, so that three general types of microorganisms including Aspergillus, bacteria and yeast are mainly included in the fermentation process of Pu ' er ripe tea, but the microorganisms are not completely consistent in different stages of different researches, which indicates that the microorganisms are extremely complex in the whole fermentation process, and are important, and the type and control of the microorganisms can directly influence the transformation process of tea, so as to influence the quality of tea, the stability of fermentation products and the fermentation period. However, little research has been done on the types of microorganisms required for the different fermentation stages of puer tea and how to control them. Chinese patent application 201610097103.3 discloses a method for processing puer tea by inoculating microbial inoculum in batches, wherein Aspergillus niger seed koji and high temperature Mucor seed koji are selected to carry out open fermentation on tea, and a method of twice tidal water inoculation is adopted to control the fermentation period to 12-15 days, but how the inoculating microorganism acts in the process is unknown, and the fermentation parameters are directly related to the external environment temperature, humidity and the like and cannot be controlled; the interaction of the microorganism causing inoculation with the microorganism itself in the tea and the microorganism in the air is not known. Chinese application 201811002772.3 discloses a puer tea processing method based on batch inoculation microbial inoculum, which is mainly implemented by inoculating Aspergillus niger, penicillium, monascus and Saccharomyces cerevisiae in batches, and establishing staged fermentation. In addition, the above reported technology still only depends on sensory evaluation to judge the quality of the fermented product, and whether the national standard that GB/T22111-2008 "geographical marker product Pu 'er tea" requires that the content of tea polyphenol in Pu' er ripe tea is lower than 15% is met is not given. Therefore, the fermentation effect is not clear, and the fermentation process cannot be precisely controlled. If the time sequence control fermentation technology (especially the accurate time sequence control fermentation technology) can be established in a targeted manner, the method has important significance for improving the fermentation efficiency and the product quality of the puer ripe tea.

Disclosure of Invention

Aiming at the defects or improvement demands of the prior art, the invention aims to provide a method for producing Pu 'er ripe tea efficiently by time sequence control fermentation, wherein after pretreatment of raw materials of the sun-cured green raw tea, the conversion of the sun-cured green raw tea materials and the characteristics of microorganisms are combined, a fermentation technology of microorganism time sequence control is determined, namely, aspergillus oryzae (Aspergillus oryzae) is inoculated firstly, fermentation parameters suitable for the aspergillus oryzae are controlled, aspergillus oryzae is planted on leaves, aspergillus niger (Aspergillus niger) is inoculated, the fermentation parameters are further accurately regulated and controlled, the quality of Pu' er ripe tea is remarkably improved, the fermentation period is effectively shortened, and the production efficiency is improved. The method shortens the fermentation period from 20 days to 432 hours (i.e. 18 days) or even 384 hours (i.e. 16 days), and the content of theabrownin in the fermentation product is high (the content of the theabrownin reaches 11.34-11.60% in the following examples), thereby remarkably saving time and economic cost and realizing the high-efficiency production of the puer ripe tea. Moreover, the method is suitable for raw materials of sun-cured raw tea with different grades, and has good action and effect.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for producing Pu' er ripe tea efficiently by time-series controlled fermentation, comprising the steps of:

(S1) preparing aspergillus strains to obtain aspergillus niger (Aspergillus niger) spore liquid and aspergillus oryzae (Aspergillus oryzae) spore liquid respectively;

(S2) preparing a sterilized fermentation tank;

(S3) preparing pretreated raw green-sun-cured raw tea, transferring the raw green-sun-cured raw tea into the fermentation tank, simultaneously, inoculating aspergillus oryzae spore liquid into the fermentation tank, and introducing sterile air to start fermentation; when the aspergillus oryzae is planted in the leaves, inoculating aspergillus niger spore liquid, and continuously introducing sterile air for fermentation;

(S4) ending fermentation when the content of tea polyphenol in the dry basis weight of the puer ripe tea obtained by fermentation in the fermentation tank is less than 15.0 wt%; and then, reducing the water content of the puer ripe tea after fermentation is finished, and obtaining puer ripe tea products.

As a further preferred aspect of the present invention, in the step (S3), the inoculating of the Aspergillus niger spore liquid is performed, in particular, at 49-72 hours after the start of fermentation.

As a further preferred mode of the invention, in the step (S3), positive pressure is maintained in the fermentation process, the pressure is lower than 0.05MPa, and in the fermentation process, the humidity in the fermentation tank is 60% -90%, when the water content of a semi-finished product in the fermentation tank is lower than the preset requirement, sterile water is required to be added to enable the water content in the semi-finished product to meet the preset requirement, preferably, the sterile water is supplemented through an atomization nozzle, the fermentation tank is required to be kept to rotate in the water supplementing process, the rotating speed is 2-10rpm, the fermentation tank is required to be kept to rotate for 5-10min after the water supplementing process is finished, and the sterile water is uniformly mixed with the semi-finished product to continue fermentation;

the weight of the raw materials of the sun-cured green tea is (2% -10%) ton/m according to the fermentation tank with the capacity scale of 0.5 cubic meters ³ The method comprises the steps of carrying out a first treatment on the surface of the The parameter condition preset requirements corresponding to each stage of fermentation are as follows:

the initial stage of fermentation: controlling the temperature in the fermentation tank to be 28-35 ℃, the ventilation amount of sterile air to be 0.5-0.8L/min, and the water content of the semi-finished fermentation product in the fermentation tank to be 35-37%;

mid-fermentation stage: controlling the temperature in the fermentation tank to be 32-37 ℃, the ventilation amount of sterile air to be 2-2.5L/min, and the water content of the semi-finished product in the fermentation tank to be 30-35%;

fermentation later stage: controlling the temperature in the fermentation tank to be 37-45 ℃, the ventilation amount of sterile air to be 2.5-3.0L/min, and the water content of the semi-finished fermentation product in the fermentation tank to be 28-30%;

fermentation end stage: controlling the temperature in the fermentation tank to be 30-37 ℃, the ventilation amount of sterile air to be 2-2.5L/min, and the water content of the semi-finished product in the fermentation tank to be 25-28%;

wherein the initial fermentation period lasts for 96-144 hours, the middle fermentation period lasts for 96-144 hours, the later fermentation period lasts for 48-96 hours, and the final fermentation period lasts for 48-144 hours;

preferably, in the initial fermentation stage after the aspergillus oryzae spore liquid is inoculated, the temperature of a fermentation tank is controlled to be 28-32 ℃, then the temperature of the fermentation tank is controlled to be 32-35 ℃, and finally the temperature of the fermentation tank is controlled to be 28-30 ℃ after the aspergillus niger spore liquid is inoculated;

more preferably, the initial fermentation period is 120 hours, the mid-fermentation period is 120 hours, the post-fermentation period is 72 hours, and the end-fermentation period is 72 hours.

As a further preferred aspect of the invention, the total fermentation time does not exceed 432 hours; preferably, the total duration of fermentation does not exceed 384 hours.

As a further preferred aspect of the present invention, in step (S3), the sterilization of the raw material of the sun-dried raw tea is specifically achieved by ultraviolet pretreatment and/or microwave pretreatment;

preferably, the ultraviolet pretreatment is to irradiate the raw materials of the green-sun-cured raw tea under an ultraviolet lamp so that the raw materials of the green-sun-cured raw tea meet the requirements of 0-20MPN/100g of escherichia coli, 0-100cfu/g of total bacteria and 0-15cfu/g of mould;

more preferably, the raw materials of the green tea are irradiated by a 30W ultraviolet lamp for 20-30min, the surface distance of the raw materials is 30-40cm, the thickness is 5-10cm, and the area is 0.5-1m ² Setting the power and the number of the ultraviolet lamps correspondingly;

the microwave pretreatment is carried out at the temperature of 70-90 ℃ for 90-180 seconds;

preferably, the ultraviolet pretreatment or the microwave pretreatment is carried out, and the raw materials of the sun-cured green tea are pretreated by ozone.

As a further preferred aspect of the present invention, in the step (S4), the lowering of the water content of the puer tea after the fermentation is completed corresponds to a can releasing process, which is specifically performed as follows: after fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing the sterile air, and maintaining the internal pressure of the fermentation tank to be positive pressure and lower than 0.05MPa.

As a further preferred aspect of the present invention, in the step (S1), the final concentration of each spore liquid satisfies 1X10 ⁶ ～1x10 ⁸ cfu/mL。

As a further preferred mode of the invention, in the step (S3), the dosage of the aspergillus oryzae spore liquid corresponding to each gram of raw material of the sun-dried green tea is 0.05-1.00mL;

when the aspergillus niger spore liquid is inoculated, the dosage of the aspergillus niger spore liquid corresponding to each gram of raw material of the sun-dried green tea is 0.05-1.00mL.

According to another aspect of the present invention, there is provided a method for producing a puer tea liquid tea product by time-series controlled efficient fermentation, characterized by comprising the steps of:

(S1) preparing aspergillus strains to obtain aspergillus niger spore liquid and aspergillus oryzae spore liquid respectively;

(S2) preparing a sterilized fermenter and a sterilized TEA liquid medium;

(S3) inoculating Aspergillus oryzae spore liquid into TEA liquid culture medium, and fermenting at 100-200rpm and 28-37deg.C; inoculating Aspergillus niger spore liquid when Aspergillus oryzae spores germinate and mycelia grow, and continuing fermentation;

(S4) ending fermentation when the theabrownin content in the liquid in the fermentation tank is more than 1300 mug/mL, so as to obtain a puer tea liquid tea product;

wherein the sterilized TEA liquid culture medium is TEA soup obtained by sterilizing a plurality of TEA leaves, adding the TEA leaves into boiling distilled water, leaching, and filtering with gauze; preferably, 1L of boiling distilled water is used for every 20g of tea; the sterilization is carried out for 20min at 121 ℃; the leaching time is not less than 2 hours.

As a further preferred aspect of the present invention, in the step (S3), the inoculating of the Aspergillus niger spore liquid is performed specifically at 6-24 hours after the start of fermentation;

preferably, in the step (S4), the fermentation completion time is 36 to 48 hours after the start of fermentation.

Compared with the prior art, the invention establishes a microorganism time sequence control fermentation technology, firstly inoculates the raw materials of the green-sun-cured raw tea with aspergillus oryzae, and then inoculates the raw materials of the green-sun-cured raw tea with aspergillus oryzae fixedly planted on the leaves, and the aspergillus niger is inoculated, so that the quality of the puer ripe tea is obviously improved, the fermentation period is effectively shortened, and the production efficiency is improved through the control of fermentation parameters and the interaction of the 2 bacteria. In addition, the time sequence control technology is also suitable for fermenting the tea soup of the puer tea, and correspondingly, the production efficiency of the liquid tea product can be improved.

Taking fermented puer ripe tea as an example, the method of the invention utilizes the microorganism time sequence control fermentation technology at the beginning and in the fermentation process, respectively adds Aspergillus oryzae and Aspergillus niger spore liquid into a fermentation tank, and can further control corresponding fermentation parameters to ensure that the spore liquid of Aspergillus oryzae corresponding to each gram of raw material of the green sun-cured raw tea is 0.05-0.1mL, and the final concentration of the spore liquid of Aspergillus oryzae and Aspergillus niger for fermenting the green sun-cured raw tea is 1 multiplied by 10 ⁶ —1×10 ⁸ cfu/mL, fermentation temperature is controlled in stages according to microorganism growth characteristics, and parameters such as tank pressure, humidity and the like of a fermentation tank are preferably controlled in the whole fermentation process, so that water is timely supplemented, and the fermentation uniformity, controllability and quality stability of puer tea are ensured. In addition, the invention also carries out ultraviolet and microwave pretreatment on the raw materials of the sun-cured raw tea of a fermentation source, taking ultraviolet pretreatment as an example, the raw materials can be sterilized and sterilized by utilizing the irradiation of an ultraviolet lamp (similar to the earlier-stage achievements of the inventor), the ultraviolet lamp is 30W during the ultraviolet pretreatment, the thickness of the raw materials of the puer tea is 5-10cm during the irradiation, the distance from the surface of the raw materials of the sun-cured raw tea to the ultraviolet lamp is 30-40cm, and the irradiation area is 0.5-1m ² The irradiation time is 20-30min, and other power ultraviolet lamps can be converted equally (for example, when the power of ultraviolet lamp is 60W, the irradiation area is increased by 1 times to 1-2m ² Other parameter conditions remain unchanged); in addition to the ultraviolet pretreatment, the raw materials of the sun-cured green tea can also be subjected to microwave pretreatment, and at the moment, the raw materials of the sun-cured green tea are transferred into a microwave pretreatment conveying device, and the treatment temperature of the microwave device is 70-90 ℃ for about 90-180 seconds (of course, the ultraviolet pretreatment and the microwave pretreatment can also be matched for use, for example, the ultraviolet pretreatment and the microwave pretreatment can be carried out firstly and then). By usingModern biotechnology processes, in particular, can employ autonomously designed horizontal solid fermenters (other types of fermenters for puer tea fermentation are equally applicable).

The invention further researches the effect and the interrelation of two microorganisms on the conversion of puer tea substances, establishes a microorganism time sequence control fermentation technology, obviously shortens the fermentation period of puer ripe tea and improves the quality of puer ripe tea products. According to the invention, the Aspergillus oryzae is inoculated firstly, and whether the Aspergillus oryzae grows in the tea leaves and the tea soup is judged by judging whether the Aspergillus oryzae is fixedly planted in the leaves or whether the mycelium grows or not, so that the inoculation time of the Aspergillus niger is guided to be accurately determined. When the aspergillus oryzae is planted in the leaf blade (or mycelium grows), the aspergillus niger is inoculated again, so that precise time sequence control is realized. The method shortens the fermentation period from 20 days to 384 hours (namely 16 days), and the content of theabrownin in the fermentation product is high (the later embodiment is exemplified, the content of the theabrownin reaches 11.34-11.60 percent), thereby obviously saving time and economic cost and realizing the high-efficiency production of the puer ripe tea. The invention can especially establish a microorganism accurate time sequence control fermentation technology, after the aspergillus oryzae spore liquid is inoculated, the temperature of a fermentation tank is controlled at 28-32 ℃ to facilitate the germination of aspergillus oryzae spores, the temperature of the fermentation tank is controlled at 32-35 ℃ to facilitate the growth of aspergillus oryzae spores, and finally the temperature of the fermentation tank is controlled at 28-30 ℃ to facilitate the enzyme production of aspergillus oryzae; the Aspergillus niger spore liquid is inoculated in the Aspergillus oryzae enzyme producing stage, and the temperature of the fermentation tank is controlled to be constant at 28-30 ℃, so that more preferable accurate control can be realized.

The timing control technology in the invention is also suitable for producing tea products by liquid fermentation, and the interaction relationship of aspergillus niger and aspergillus oryzae is utilized, fermentation is promoted by timing inoculation, so that the substances such as polyphenol in tea soup are efficiently and quickly converted into theabrownin, and similar effects are achieved.

In conclusion, the invention establishes a method for producing the puer ripe tea efficiently by time sequence control fermentation, namely, a control technology of fermentation of the sun-cured green raw tea is determined. The Pu' er ripe tea produced by the method has high quality, good taste, bright soup color and brown-red leaf bottom, further shortens the fermentation period and improves the production efficiency. Similarly, the time sequence control technology is also applicable to liquid fermentation production of tea products, and can achieve similar effects.

Drawings

FIG. 1 is a comparison of Pu' er tea soup color under different fermentation conditions; wherein a in fig. 1 corresponds to the soup color of the green-sun-dried raw tea (raw material) obtained by sun-drying the second-stage fresh leaves, b in fig. 1 corresponds to the soup color of the green-sun-dried raw tea (raw material) obtained by sun-drying the second-stage fresh leaves for 504 hours in conventional fermentation (without timing control), c in fig. 1 corresponds to the soup color of the green-sun-dried raw tea (raw material) obtained by sun-drying the second-stage fresh leaves for 432 hours in accurate timing control fermentation, and d in fig. 1 corresponds to the soup color of the green-sun-dried raw tea (raw material) obtained by sun-drying the five-stage fresh leaves for 384 hours in accurate timing control fermentation.

FIG. 2 is a flow chart of conventional fermentation and timing control fermentation compared in the examples below.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Based on the method, sequential inoculation can be performed according to the following steps, so that the puer ripe tea is produced by high-efficiency fermentation:

(1) Preparing aspergillus strain: picking up a small amount of Aspergillus niger (Aspergillus niger) and Aspergillus oryzae (Aspergillus oryzae) for fermenting sun-dried green tea under aseptic condition, inoculating to PDA agar medium, culturing at 28deg.C, culturing for 5-7 days, and preparing into spore liquid with appropriate amount of sterile water to obtain final concentration of about 1×10 ⁷ cfu/mL。

(2) Sterilizing a fermentation tank: sterilizing the interior of the fermentation tank and the pipeline by adopting high-temperature steam, and maintaining the temperature at 121 ℃ for 20min. The fermentation tank used in the embodiment of the invention is a solid fermentation tank with accurate and controllable operation parameters, which is developed and obtained by the inventor in advance (the detailed arrangement of each component in the fermentation tank can be seen in Chinese application patent CN 201920366567.9).

(3) Pretreatment of raw materials: according to the existing sun-drying technology, sun-drying fresh puerh tea leaves to obtain sun-dried raw tea; then, 50kg of raw green tea is subjected to ultraviolet pretreatment by taking the raw green tea as a raw material, the number of ultraviolet lamps is 20, the tea thickness is about 5cm, the distance between the tea and the ultraviolet lamps is 30cm, and the irradiation area of a single ultraviolet lamp is 0.5m ² After the treatment time is 30min and the ultraviolet treatment, the raw materials are further transferred into a microwave pretreatment conveying device, wherein the treatment temperature of the microwave device is 90 ℃, and the treatment time is about 90 seconds, so that the total bacteria count in the raw materials is 0-8MPN/100g, the total bacteria count is 0-40cfu/g, and the mold count is 0-6cfu/g.

(4) Inoculating fermentation in fermentation tank

Sequential inoculation fermentation: 50kg of pretreated raw materials of sun-dried green tea are firstly transferred into a sterilized 0.5 cubic meter fermentation tank, and then 2.5-5.0L of aspergillus oryzae spore liquid is connected into the fermentation tank through an atomization nozzle to start fermentation. When Aspergillus oryzae is planted in the leaf (49-72 hours after fermentation, such as 60 hours), 2.5-5.0L of Aspergillus niger spore liquid is added. In the actual operation process, the trypan blue mycelium staining method can also be used for judging the growth condition of the aspergillus oryzae in the tea leaves and the tea soup, and guiding to accurately determine the inoculation time of the aspergillus niger.

The fermentation is carried out in each stage by controlling the following parameters, the pressure of the tank is maintained to be positive pressure in the whole fermentation process, and the pressure is lower than 0.05MPa;

controlling the temperature parameters in the fermentation tank in the fermentation process as shown in table 1, controlling the humidity in the fermentation tank to be 60% -90%, sampling and detecting the water content in the tea leaves every 48 hours, supplementing sterile water through an atomization nozzle if the water content in the tea leaves is lower than the water content in the corresponding stage, enabling the water content in the tea leaves to be maintained at the water content in the corresponding stage, enabling the fermentation tank to keep rotating in the water supplementing process, enabling the rotating speed to be 2rpm, continuing to rotate the fermentation tank after the water supplementing is finished, and maintaining for 3 minutes, so that the supplemented sterile water and the tea leaves in the tank are uniformly mixed;

(5) Ending fermentation: taking tea samples after 313 hours in the fermentation process, detecting the content of tea polyphenol, taking 3 parallel samples for each sample, taking an average value of the results, and ending the fermentation when the content of tea polyphenol is less than 15%.

(6) And (3) tank discharge: after fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing sterile air, maintaining the internal pressure of the fermentation tank to be positive pressure, and discharging the fermented puer ripe tea from the fermentation tank when the water content in the tea is less than or equal to 15 percent, wherein the ventilation amount is 5L/min. The above operation flow is schematically shown in fig. 2.

TABLE 1 parameter control for different fermentation stages in fermentors

Note that: the period of 0-120 hours is divided into 3 sub-stages, mainly considering that the germination temperature of aspergillus oryzae spores is 28-32 ℃, the growth temperature is 32-35 ℃, the optimal enzyme production temperature is 28-30 ℃, and the growth temperature of aspergillus niger is about 28 ℃, so that the fermentation initial stage is further divided into 3 sub-stages for facilitating the fermentation of aspergillus oryzae and aspergillus niger, and the accurate time sequence control is realized; of course, the whole initial fermentation stage may be controlled as follows without further subdivision: the temperature in the fermentation tank is 28-35 ℃, the ventilation amount of sterile air is 0.5-0.8L/min, the water content of the semi-finished product in the fermentation tank is 35-37%, and the time sequence control is realized.

Example 1

This example focused on the effect of Aspergillus niger (Aspergillus niger), aspergillus oryzae (Aspergillus oryzae) on material conversion in TEA broth, comprising the steps of:

(1) Preparation of Aspergillus strain

Picking and fermenting Aspergillus niger and Aspergillus oryzae for producing puer ripe tea under aseptic condition, inoculating to PDA agar medium, culturing at 28deg.C, respectively culturing two kinds of Aspergillus for 5-7 days, and preparing into spore liquid with proper amount of sterile water to obtain spore liquid with final concentration of about 1×10 ⁷ cfu/mL。

The TEA liquid medium used hereinafter was prepared as follows: sterilizing 20g tea leaves at 121deg.C for 20min. After sterilization, the tea leaves are added into 1L of boiling distilled water, leached for 2 hours, filtered by gauze and packaged in triangular bottles, and all the operations are performed in an ultra clean bench.

(2) Aspergillus liquid fermentation

Fermenting Aspergillus niger: 5.0mL of Aspergillus niger spore liquid was inoculated into TEA liquid medium and fermented for 48 hours.

Fermenting Aspergillus oryzae: 5.0mL of Aspergillus oryzae spore liquid was inoculated into TEA liquid medium and fermented for 48 hours.

Aspergillus niger and Aspergillus oryzae are fermented together: 2.5mL of Aspergillus niger and Aspergillus oryzae spore liquid were inoculated into TEA liquid medium and fermented for 48 hours.

The fermentation temperature was 37℃and the rotation speed was 150rpm, and 3 replicates were obtained for each sample, and the results were averaged.

Based on the above fermentation, the results of the tea polyphenol and theabrownin content are shown in Table 2. The content of tea polyphenol in the Aspergillus niger fermented tea soup is 214.51 mug/mL, and the content of theabrownin is 1319.75 mug/mL; the content of tea polyphenol in the Aspergillus oryzae fermented tea soup is 827.69 mug/mL, and the content of theabrownin is 1537.67 mug/mL; the tea polyphenol content in the Aspergillus niger and Aspergillus oryzae co-fermented tea soup is 441.98 mug/mL, and the theabrownin content is 1779.12 mug/mL. More tea polyphenol is consumed in the fermentation process of the aspergillus niger, but the synthesis rate of theabrownin is lower; the tea polyphenol content is more reserved in the Aspergillus oryzae fermentation process, and the conversion and synthesis amount of theabrownin is higher; and the Aspergillus niger and the Aspergillus oryzae act together, the theabrownin is converted and synthesized with highest efficiency, and the consumption of the tea polyphenol is between the consumption of the Aspergillus niger and the Aspergillus oryzae which are fermented independently.

TABLE 2 comparison of theabrownin content by inoculating liquid fermented tea polyphenols alone and in combination

Note that: μg/mL is a unit representation of the content of substances in a liquid, representing the mass of tea polyphenols or theabrownins contained in per milliliter of tea soup; of course, their inclusionThe amount may also be converted into% units, i.e. the content of tea polyphenols and theabrownins per g of tea leaf (conversion formula 1 μg=1 (μg/mL) ×1mL,1 μg/g=1 μg/1g,100% =1 μg/g×10 ^-6 *100, wherein 1 μg=10 ^-6 g)。

Example 2

In order to consume tea polyphenol as little as possible in the fermentation process of puer tea and to make the conversion and synthesis amount of theabrownin large, the embodiment focuses on comparing the time sequence inoculation fermentation technology (including the accurate time sequence control fermentation technology) with the conventional fermentation process and fermentation effect, and comprises the following steps:

(1) Preparation of Aspergillus strain

Picking and fermenting Aspergillus niger (Aspergillus niger) and Aspergillus oryzae (Aspergillus oryzae) under aseptic condition, inoculating to PDA agar medium, culturing at 28deg.C, culturing for 5-7 days, and preparing into spore liquid with appropriate amount of sterile water to obtain final concentration of about 1×10 ⁷ cfu/mL。

(2) Fermentation tank sterilization

Sterilizing the interior of the puer tea fermentation tank and the pipeline by adopting high-temperature steam, and maintaining the temperature of 121 ℃ for 20min.

(3) Pretreatment of raw materials

Carrying out ultraviolet pretreatment on 50kg of sun-dried raw tea raw materials, wherein the number of ultraviolet lamps is 20, the thickness of tea leaves is about 5cm, the distance between the tea leaves and the ultraviolet lamps is 30cm, and the irradiation area of a single ultraviolet lamp is 0.5m ² After the treatment time is 30min and the ultraviolet treatment, the raw materials are further transferred into a microwave pretreatment conveying device, wherein the treatment temperature of the microwave device is 70 ℃ and the treatment time is about 180 seconds, so that the total bacteria count is 0-40cfu/g and the mold count is 0-6cfu/g of the escherichia coli in the raw materials of the sun-dried green raw tea; the embodiment adopts the sun-cured raw tea obtained by sun-curing the second-stage fresh leaves as the raw material (the grading basis is GB/T22111-2008 "geographical marking product Pu' er tea", as shown in the attached table below);

(4) Inoculating fermentation in fermentation tank

Conventional fermentation:

50kg of pretreated raw material (with the water content of 10%) of the sun-cured green tea is firstly transferred into a sterilized 0.5 cubic meter fermentation tank, then 14.23L of sterile water, 2.5L of aspergillus oryzae spore liquid and 2.5L of aspergillus niger spore liquid are simultaneously connected into the fermentation tank through an atomizing nozzle, and the mixture is uniformly mixed, so that the inoculation amount is 5%, the initial water content is 35%, and fermentation is started.

Sequential inoculation fermentation (including accurate sequential control fermentation): 50kg of pretreated raw material (with water content of 10%) of sun-cured green tea is firstly transferred into a sterilized 0.5 cubic meter fermentation tank, then 16.73L of sterile water and 2.5L of aspergillus oryzae spore liquid are connected into the fermentation tank through an atomizing nozzle, and uniformly mixed, so that the inoculation amount is 2.5%, the initial water content is 35%, and fermentation is started. At 49-72 hours (all 60 hours used in this example) Aspergillus oryzae was colonized on the leaf blades, followed by 2.5L of Aspergillus niger spore liquid (inoculum size 2.5%).

The fermentation is carried out in each stage by controlling the following parameters, the pressure of the tank is maintained to be positive pressure in the whole fermentation process, and the pressure is lower than 0.05MPa;

the temperature parameters in the fermentation tank are controlled as shown in tables 3, 4 and 5 respectively in the conventional fermentation, the accurate time sequence control fermentation and the time sequence inoculation fermentation process, the humidity in the fermentation tank is controlled to be 60% -90%, the water content in the tea is detected through sampling every 48 hours, if the water content in the tea is lower than the water content in the corresponding stage, sterile water is supplemented through an atomization nozzle, the water content in the tea is maintained at the water content in the corresponding stage, the fermentation tank is kept to rotate in the water supplementing process, the rotating speed is 2rpm, the fermentation tank is continuously rotated after the water supplementing is finished, the maintenance is carried out for 3min, and the supplemented sterile water and the tea in the tank are uniformly mixed;

(5) Ending fermentation

Taking tea samples at the later stage of the fermentation process, detecting the content of tea polyphenol, taking 3 parallel samples for each sample, taking an average value of the results, and ending the fermentation when the content of the tea polyphenol is less than 15%.

(6) Tank for placing

After fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing sterile air, maintaining the internal pressure of the fermentation tank to be positive pressure, and discharging the fermented puer ripe tea from the fermentation tank when the water content in the tea is less than or equal to 15 percent, wherein the ventilation amount is 5L/min.

TABLE 3 temperature control of the different fermentation stages in a conventional fermentation process

TABLE 4 precise time sequence control of temperature control for different fermentation stages in a fermentation process

TABLE 5 temperature control of different fermentation stages in sequential inoculation fermentation process

Based on the inoculation fermentation production method, conventional fermentation and accurate time sequence control fermentation, and the results of the content of tea polyphenol and theabrownin are shown in Table 6. Conventional fermentation for producing puer ripe tea, wherein the tea polyphenol content is reduced from 23.10% in raw materials of sun-dried raw tea (soup color is shown as a in figure 1) to 14.91%, the theabrownin content is increased from 1.64% to 7.29%, and the fermentation period is 504 hours (i.e. 21 days, soup color is shown as b in figure 1); the fermentation time sequence is controlled accurately for 432 hours (namely 18 days), the tea polyphenol content in the puer ripe tea is 14.78 percent, and the theabrownin content is 11.60 percent (the soup color is shown as c in figure 1).

The fermentation time sequence is controlled to be 480 hours (namely 20 days), the tea polyphenol content in the puer ripe tea is 14.85 percent, and the theabrownin content is 9.37 percent. The high-quality puer ripe tea is obtained under the three conditions, has no taste, good taste, brighter soup color and brown-red leaf bottom, is obviously higher than the national standard, but has higher theabrownin conversion efficiency and shorter fermentation period by controlling fermentation according to the accurate time sequence.

TABLE 6 Mixed Vaccination and time series Vaccination solid state fermentation tea polyphenols, theabrownin content comparison

Example 3

The embodiment is a method for efficiently producing puer ripe tea based on accurate time sequence control fermentation, which comprises the following steps:

(1) Preparation of Aspergillus strain

Picking and fermenting Aspergillus niger (Aspergillus niger) and Aspergillus oryzae (Aspergillus oryzae) under aseptic condition, inoculating to PDA agar medium, culturing at 28deg.C, culturing for 5-7 days, and preparing into spore liquid with appropriate amount of sterile water to obtain final concentration of about 1×10 ⁷ cfu/mL。

(2) Fermentation tank sterilization

Sterilizing the interior of the fermentation tank and the pipeline for producing the puer ripe tea by adopting high-temperature steam, and maintaining the temperature of 121 ℃ for 20min.

(3) Pretreatment of raw materials

Carrying out ultraviolet pretreatment on 50kg of sun-dried raw tea raw materials, wherein the number of ultraviolet lamps is 20, the thickness of tea leaves is about 5cm, the distance between the tea leaves and the ultraviolet lamps is 30cm, and the irradiation area of a single ultraviolet lamp is 0.5m ² After the treatment time is 30min and the ultraviolet treatment, the raw materials are further transferred into a microwave pretreatment conveying device, wherein the treatment temperature of the microwave device is 70 ℃ and the treatment time is about 180 seconds, so that the total bacteria count in the raw materials is 0-8MPN/100g, the total bacteria count is 0-40cfu/g, and the mold count is 0-6cfu/g; the embodiment adopts the sun-cured raw tea obtained by sun-curing five-stage fresh leaves as a raw material;

(4) Inoculating fermentation in fermentation tank

Accurate time sequence control fermentation: 50kg of pretreated raw material (with water content of 10%) of sun-cured green tea is firstly transferred into a sterilized 0.5 cubic meter fermentation tank, then 16.73L of sterile water and 2.5L of aspergillus oryzae spore liquid are connected into the fermentation tank through an atomizing nozzle, and uniformly mixed, so that the inoculation amount is 2.5%, the initial water content is 35%, and fermentation is started. When Aspergillus oryzae was cultured for 49 hours, it was planted in the leaf, and then inoculated with 2.5L of Aspergillus niger spore liquid (inoculum size: 2.5%).

The fermentation is carried out in each stage by controlling the following parameters, the pressure of the tank is maintained to be positive pressure in the whole fermentation process, and the pressure is lower than 0.05MPa;

in the accurate time sequence control fermentation process, the reference number in the fermentation tank is as shown in table 7, the humidity in the fermentation tank is controlled to be 60% -90%, the water content in the tea is detected through sampling every 48 hours, if the water content in the tea is lower than the water content in the corresponding stage, sterile water is supplemented through an atomization nozzle, the water content in the tea is maintained at the water content in the corresponding stage, the fermentation tank is kept rotating in the water supplementing process, the rotating speed is 2rpm, the fermentation tank is continuously rotated after the water supplementing is finished, the fermentation tank is maintained for 3 minutes, and the supplemented sterile water and the tea in the tank are uniformly mixed;

(5) Ending fermentation

Taking tea samples at the later stage of the fermentation process, detecting the content of tea polyphenol, taking 3 parallel samples for each sample, taking an average value of the results, and ending the fermentation when the content of the tea polyphenol is less than 15%.

(6) Tank for placing

After fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing sterile air, maintaining the internal pressure of the fermentation tank to be positive pressure, and discharging the tea when the water content in the tea is less than or equal to 15% and the ventilation amount is 5L/min.

TABLE 7 parameter control for different fermentation stages in fermentors

Based on the inoculation fermentation production method, the results of the content of tea polyphenol and theabrownin are shown in Table 8. The fermentation is precisely controlled in time sequence for 384 hours (namely 16 days), the tea polyphenol content in the puer ripe tea is reduced from 21.16% in the raw material of the sun-cured green raw tea to 14.05%, and the theabrownin content is increased from 2.59% to 11.34% (the soup color is shown as d in figure 1).

Table 8 accurate time sequence control of fermented tea polyphenols, theabrownin content

Therefore, the method for producing the puer ripe tea by precisely controlling the time sequence and fermenting can be used for efficiently converting theabrownin from raw materials with different grades.

Example 4

The embodiment is a method for efficiently producing puer ripe tea based on accurate time sequence control fermentation, which comprises the following steps:

(1) Preparation of Aspergillus strain

Picking and fermenting under aseptic condition to obtain a small amount of Aspergillus niger (Aspergillus niger) and Aspergillus oryzae (Aspergillus oryzae), inoculating into PDA agar medium, culturing at 28deg.C, respectively culturing two kinds of Aspergillus for 5-7 days, and preparing into spore liquid with proper amount of sterile water to obtain spore liquid with final concentration of about 1×10 ⁷ cfu/mL。

(2) Fermentation tank sterilization

Sterilizing the interior of a fermentation tank and a pipeline for producing puer tea by fermentation by high-temperature steam, and maintaining the temperature at 121 ℃ for 20min.

(3) Pretreatment of raw materials

Carrying out ultraviolet pretreatment on 50kg of sun-dried raw tea raw materials, wherein the number of ultraviolet lamps is 20, the thickness of tea leaves is about 5cm, the distance between the tea leaves and the ultraviolet lamps is 30cm, and the irradiation area of a single ultraviolet lamp is 0.5m ² After the treatment time is 30min and the ultraviolet treatment, the raw materials are further transferred into a microwave pretreatment conveying device, wherein the treatment temperature of the microwave device is 70 ℃ and the treatment time is about 180 seconds, so that the total bacteria count in the raw materials is 0-8MPN/100g, the total bacteria count is 0-40cfu/g, and the mold count is 0-6cfu/g; the embodiment adopts the sun-cured raw tea obtained by sun-curing five-stage fresh leaves as a raw material;

(4) Inoculating fermentation in fermentation tank

Accurate time sequence control fermentation: 50kg of pretreated raw material (with water content of 10%) of sun-cured green tea is firstly transferred into a sterilized 0.5 cubic meter fermentation tank, then 16.73L of sterile water and 2.5L of aspergillus oryzae spore liquid are connected into the fermentation tank through an atomizing nozzle, and uniformly mixed, so that the inoculation amount is 2.5%, the initial water content is 35%, and fermentation is started. When Aspergillus oryzae was cultured for 72 hours, it was planted in the leaf, and then inoculated with 2.5L of Aspergillus niger spore liquid (inoculum size was 2.5%).

The fermentation is carried out in each stage by controlling the following parameters, the pressure of the tank is maintained to be positive pressure in the whole fermentation process, and the pressure is lower than 0.05MPa;

controlling parameters in a fermentation tank in the time sequence inoculation fermentation process as shown in table 9, controlling humidity in the fermentation tank to be 60% -90%, detecting water content in tea by sampling every 48 hours, and if the water content in the tea is lower than the water content in the corresponding stage, supplementing sterile water through an atomization nozzle to maintain the water content in the tea at the water content in the corresponding stage, wherein the fermentation tank is kept to rotate in the water supplementing process, the rotating speed is 2rpm, continuing to rotate the fermentation tank after the water supplementing is finished, and maintaining for 3min, so that the supplemented sterile water and the tea in the tank are uniformly mixed;

(5) Ending fermentation

Taking tea samples at the later stage of the fermentation process, detecting the content of tea polyphenol, taking 3 parallel samples for each sample, taking an average value of the results, and ending the fermentation when the content of the tea polyphenol is less than 15%.

(6) Tank for placing

After fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing sterile air, maintaining the internal pressure of the fermentation tank to be positive pressure, and discharging the fermented puer ripe tea from the fermentation tank when the water content in the tea is less than or equal to 15 percent, wherein the ventilation amount is 5L/min.

TABLE 9 parameter control for different fermentation stages in fermentors

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Based on the inoculation fermentation production method, the results of the tea polyphenol and theabrownin content are shown in Table 10. Fermenting for 384 hours (16 days) in time sequence, wherein the tea polyphenol content in the puer ripe tea is reduced from 23.99% in the raw material of the sun-cured green raw tea to 13.72%, and the theabrownin content is increased from 2.01% to 10.55%.

Table 10 precise time sequence control of solid state fermentation tea polyphenols, theabrownin content

Therefore, the method for producing the puer ripe tea efficiently by precisely controlling the fermentation in time sequence is suitable for the fermentation process with controllable temperature parameters.

In addition to the solid fermentation tanks used in the above examples, the timing control technique of the present invention is equally applicable to the production of tea products by liquid fermentation, in which case liquid fermentation tanks may be used. The essence of the solid state fermentation process of tea leaves is that extracellular enzymes (such as polyphenol oxidase, peroxidase and the like) secreted by microorganisms convert substances such as polyphenol in tea leaves, and finally substances such as theabrownin are generated. Similarly, the liquid fermentation process of tea soup is similar to the solid fermentation process, and the microorganisms secrete extracellular enzymes to convert substances such as polyphenol into theabrownin, and the microorganisms can more easily act in a liquid system. Thus, the timing control technique of the present invention is equally applicable to the production of tea products by liquid fermentation.

The classification index of the fresh leaves produced by fermentation is shown in the following table.

The attached table: GB/T22111-2008 "geographical marker product Pu' er tea" prescribes fresh leaf classification index

Level of	Ratio of bud to leaf
		Special grade	More than 70% of one bud and one leaf and less than 30% of two leaves
First level	The two leaves of one bud account for more than 70 percent, and the other buds with the same tenderness account for less than 30 percent
		Second-level	One bud with two or three leaves accounting for 60 percent and the other buds with the same tendernessAccounting for less than 40 percent
Three stages	One bud, two and three leaves account for more than 50 percent, and other buds and leaves with the same tenderness account for less than 50 percent
		Four-stage	One bud with three or four leaves accounting for more than 70 percent and the other buds with the same tenderness accounting for less than 30 percent
Five-stage	More than 50% of three or four leaves of one bud and less than 50% of other buds and leaves with the same tenderness

The present invention, not described in detail, can be performed with reference to the prior art (for example, with reference to chinese patent 201810064877.5, "a stable and controllable high quality puer tea and its fermentation production method").

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (10)

1. A method for efficiently producing puer ripe tea by time sequence control fermentation is characterized by comprising the following steps:

(S1) preparing aspergillus strains to obtain aspergillus niger (Aspergillus niger) spore liquid and aspergillus oryzae (Aspergillus oryzae) spore liquid respectively;

(S2) preparing a sterilized fermentation tank;

(S3) preparing pretreated raw green-sun-cured raw tea, transferring the raw green-sun-cured raw tea into the fermentation tank, simultaneously, inoculating aspergillus oryzae spore liquid into the fermentation tank, and introducing sterile air to start fermentation; when the aspergillus oryzae is planted in the leaves, inoculating aspergillus niger spore liquid, and continuously introducing sterile air for fermentation;

(S4) ending fermentation when the content of tea polyphenol in the dry basis weight of the puer ripe tea obtained by fermentation in the fermentation tank is less than 15.0 wt%; and then, reducing the water content of the puer ripe tea after fermentation is finished, and obtaining puer ripe tea products.

2. The method of claim 1, wherein in step (S3), the inoculating of the aspergillus niger spore liquid is performed, in particular, at 49-72 hours after the start of fermentation.

3. The method according to claim 1, wherein in the step (S3), positive pressure is maintained during fermentation, the pressure is lower than 0.05MPa, and during fermentation, the humidity in the fermentation tank is 60% -90%, when the water content of the semi-finished product in the fermentation tank is lower than the preset requirement, sterile water is required to be added to enable the water content in the semi-finished product to meet the preset requirement, preferably, the sterile water is added through an atomization nozzle, the fermentation tank is required to be kept to rotate during water adding, the rotating speed is 2-10rpm, the fermentation tank is required to be kept to rotate for 5-10min after the water adding process is finished, and the sterile water is uniformly mixed with the semi-finished product to continue fermentation;

the weight of the raw materials of the sun-cured green tea is (2% -10%) ton/m according to the fermentation tank with the capacity scale of 0.5 cubic meters ³ The method comprises the steps of carrying out a first treatment on the surface of the The parameter condition preset requirements corresponding to each stage of fermentation are as follows:

the initial stage of fermentation: controlling the temperature in the fermentation tank to be 28-35 ℃, the ventilation amount of sterile air to be 0.5-0.8L/min, and the water content of the semi-finished fermentation product in the fermentation tank to be 35-37%;

mid-fermentation stage: controlling the temperature in the fermentation tank to be 32-37 ℃, the ventilation amount of sterile air to be 2-2.5L/min, and the water content of the semi-finished product in the fermentation tank to be 30-35%;

fermentation later stage: controlling the temperature in the fermentation tank to be 37-45 ℃, the ventilation amount of sterile air to be 2.5-3.0L/min, and the water content of the semi-finished fermentation product in the fermentation tank to be 28-30%;

fermentation end stage: controlling the temperature in the fermentation tank to be 30-37 ℃, the ventilation amount of sterile air to be 2-2.5L/min, and the water content of the semi-finished product in the fermentation tank to be 25-28%;

wherein the initial fermentation period lasts for 96-144 hours, the middle fermentation period lasts for 96-144 hours, the later fermentation period lasts for 48-96 hours, and the final fermentation period lasts for 48-144 hours;

preferably, in the initial fermentation stage after the aspergillus oryzae spore liquid is inoculated, the temperature of a fermentation tank is controlled to be 28-32 ℃, then the temperature of the fermentation tank is controlled to be 32-35 ℃, and finally the temperature of the fermentation tank is controlled to be 28-30 ℃ after the aspergillus niger spore liquid is inoculated;

more preferably, the initial fermentation period is 120 hours, the mid-fermentation period is 120 hours, the post-fermentation period is 72 hours, and the end-fermentation period is 72 hours.

4. The method of claim 1, wherein the total duration of fermentation is no more than 432 hours; preferably, the total duration of fermentation does not exceed 384 hours.

5. The method according to claim 1, wherein in step (S3) the sterilization of the raw sun-dried raw tea material is in particular achieved by uv pretreatment and/or microwave pretreatment;

preferably, the ultraviolet pretreatment is to irradiate the raw materials of the green-sun-cured raw tea under an ultraviolet lamp so that the raw materials of the green-sun-cured raw tea meet the requirements of 0-20MPN/100g of escherichia coli, 0-100cfu/g of total bacteria and 0-15cfu/g of mould;

more preferably, the raw materials of the green tea are irradiated by a 30W ultraviolet lamp for 20-30min, the surface distance of the raw materials is 30-40cm, the thickness is 5-10cm, and the area is 0.5-1m ² Setting the power and the number of the ultraviolet lamps correspondingly;

the microwave pretreatment is carried out at the temperature of 70-90 ℃ for 90-180 seconds;

preferably, the ultraviolet pretreatment or the microwave pretreatment is carried out, and the raw materials of the sun-cured green tea are pretreated by ozone.

6. The method of claim 1, wherein in the step (S4), the lowering of the moisture content of the puer tea after the fermentation is completed corresponds to a can-releasing process, which is specifically performed as follows: after fermentation is finished, controlling the temperature in the fermentation tank to be 37-45 ℃, continuously introducing the sterile air, and maintaining the internal pressure of the fermentation tank to be positive pressure and lower than 0.05MPa.

7. The method of claim 1, wherein in step (S1), the final concentration of each spore fluid is 1X10 ⁶ ～1x10 ⁸ cfu/mL。

8. The method of claim 7, wherein in the step (S3), the amount of aspergillus oryzae spore liquid corresponding to each gram of raw green tea is 0.05-1.00mL;

when the aspergillus niger spore liquid is inoculated, the dosage of the aspergillus niger spore liquid corresponding to each gram of raw material of the sun-dried green tea is 0.05-1.00mL.

9. A method for producing Pu' er tea liquid tea products by time-sequence control efficient fermentation, which is characterized by comprising the following steps:

(S1) preparing aspergillus strains to obtain aspergillus niger spore liquid and aspergillus oryzae spore liquid respectively;

(S2) preparing a sterilized fermenter and a sterilized TEA liquid medium;

(S3) inoculating Aspergillus oryzae spore liquid into TEA liquid culture medium, and fermenting at 100-200rpm and 28-37deg.C; inoculating Aspergillus niger spore liquid when Aspergillus oryzae spores germinate and mycelia grow, and continuing fermentation;

(S4) ending fermentation when the theabrownin content in the liquid in the fermentation tank is more than 1300 mug/mL, so as to obtain a puer tea liquid tea product;

wherein the sterilized TEA liquid culture medium is TEA soup obtained by sterilizing a plurality of TEA leaves, adding the TEA leaves into boiling distilled water, leaching, and filtering with gauze; preferably, 1L of boiling distilled water is used for every 20g of tea; the sterilization is carried out for 20min at 121 ℃; the leaching time is not less than 2 hours.

10. The method of claim 9, wherein in step (S3), the inoculating of the aspergillus niger spore liquid is performed in particular at 6-24 hours after the start of fermentation;

preferably, in the step (S4), the fermentation completion time is 36 to 48 hours after the start of fermentation.

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