Method for assisting pile fermentation of Pu'er tea

Abstract

The invention relates to a pile fermentation technology of Pu'er tea, in particular to a method for assisting pile fermentation of Pu'er tea. Mixing and crushing the tea leaves and water, and filtering to obtain tea leaf juice; pu'er raw tea / raw tea is used as a raw material, and tea leaf juice is sprayed at the initial stage of pile fermentation; and after pile fermentation is finished, drying the tea sample to obtain a finished product of the fermented Pu'er tea. The tea leaves are used for assisting the pile fermentation of the Pu'er tea, so that the pile fermentation time of the Pu'er tea can be greatly shortened, the flavor and quality of the fermented Pu'er tea can be improved, the high value of the tea leaves is completed, and the method has a very good reference value for actual production.

Description

Technical Field

[0001] The invention relates to a pile fermentation technology of Pu'er tea, and in particular to a method for assisting the pile fermentation of Pu'er tea. Background Art

[0002] Pu'er ripe tea is a traditional tea variety in Yunnan Province, China, and is considered a geographical indication product. In the past few decades, Pu'er ripe tea has been increasingly favored worldwide, mainly because of its special flavor and good health and pharmacological effects, which meet the tastes and health needs of modern people. Pu'er ripe tea is made from Yunnan large-leaf tea into sun-dried green tea (Pu'er raw tea), which is then further obtained through pile fermentation. During the pile fermentation process, due to the action of microorganisms, moisture and heat, and enzymes, the substances contained in the tea are transformed, thus forming the unique quality characteristics of Pu'er ripe tea. In the past pile fermentation process, producers often performed operations such as tide and pile turning on Pu'er tea based on production experience. The pile fermentation process is under natural environment, and the fermentation cycle is relatively long, generally up to 50 to 60 days. Many uncertain factors will appear in this process and affect the overall fermentation and quality of Pu'er tea. Therefore, improving the fermentation process of Pu'er tea and shortening the fermentation time are of great significance to improving the quality of Pu'er ripe tea.

[0003] At present, the research on Pu'er tea fermentation process mainly focuses on inoculating dominant strains, such as "Application of Saccharomyces cerevisiae and Lactobacillus in Pu'er tea fermentation" disclosed in CN113749164A, exogenous addition of enzymes and sugars, such as "Pu'er tea and its method for adding sugars to promote fermentation" disclosed in CN103315079A, improving or inventing pile fermentation devices, etc., such as "Pu'er tea pile fermentation equipment" disclosed in CN206498855U, which generally have high costs and complex operations. Some of the exogenous additives, such as exogenous inoculation of dominant strains, may not be clear about the safety of their strains, and it is uncertain whether they can be used in actual industrial production. Therefore, a safer, more convenient and low-cost method for assisting Pu'er tea pile fermentation is needed. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the current research on Pu'er tea fermentation process mainly focuses on inoculating superior strains, adding exogenous enzymes and sugars, improving or inventing pile fermentation devices, etc., which are generally costly and complicated to operate. Moreover, the general exogenous additives, such as the above-mentioned sugars, enzymes or inoculated strains, and the above-mentioned methods are still applied to the Pu'er tea fermentation process, and there are still certain defects, such as cost issues. .

[0005] In view of the problems of the prior art, the present invention discloses a method for assisting the pile fermentation of Pu'er tea, which utilizes tea leaves as natural exogenous additives to add into the fermentation of Pu'er tea, so as to shorten the pile fermentation time of Pu'er tea and improve the quality of tea. This not only realizes the efficient utilization of tea resources, but also shortens the fermentation time of Pu'er tea and improves the quality of Pu'er tea.

[0006] To achieve the above purpose, the technical solution of the present invention is: a method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0007] (1) Freshly picked tea leaves are mixed with water and crushed, and tea leaf juice is obtained after filtering, and the material-liquid ratio of tea leaves to water is 1:1 to 1:10. If the concentration is too high, it is difficult to collect the tea leaf juice during crushing; if the concentration is too low, it is easy to add excessive water at the tidal stage or reduce the amount of tea leaf juice added.

[0008] (2) Use Pu'er raw tea / raw tea as raw material, add tide water first and then add the above tea leaf juice.

[0009] (3) After the pile fermentation is completed, the tea leaves are dried to obtain the Pu'er cooked tea product.

[0010] Tea leaves are a natural form of tea, and there is no limit to their use in assisting the fermentation of Pu'er ripe tea. Tea leaves are rich in amino acids, tea polysaccharides and enzymes. Directly adding tea leaves to the tea pile after crushing and centrifugal filtration not only greatly simplifies the extraction steps and reduces production costs, but the rich enzymes in the tea leaves are also expected to accelerate the rate of pile fermentation. In addition, the carbohydrates and other components contained in tea leaves are more conducive to protecting the activity of endogenous enzymes such as polyphenol oxidase and glycosidase, so that they can play a better role; at the same time, during the pile fermentation process, there is a certain synergistic effect between the various substances in the tea leaves, which is better than the effect of adding a single ingredient, and can further improve the flavor of Pu'er ripe tea.

[0011] Therefore, using the juice of tea leaves to assist the fermentation of Pu'er tea piles is not only expected to shorten the fermentation time of Pu'er tea piles, but also may have a significant effect on the quality of tea. On the other hand, due to the slow fermentation speed of Pu'er tea in some parts of my country, large amounts of tea leaves as tea raw materials are often piled up and wasted. Adding unused tea raw materials as exogenous additives to the tea pile can also effectively avoid large-scale waste, and can also further increase the output of Pu'er tea and promote the development of the regional tea economy.

[0012] Furthermore, the tea leaves in step (1) include tea buds, fresh tea leaves, old tea leaves, or a mixture of more than one of these. Generally, the raw materials for Pu'er cooked tea introduced in the tea industry are all Yunnan large-leaf tea. The present invention preferably uses Yunnan large-leaf tea because its large leaves have richer internal substances and can better complete the conversion of the internal substances in the pile fermentation stage.

[0013] Furthermore, the crushing in step (1) is carried out by grinding, crushing with a tissue crusher or crushing with a wall breaking machine.

[0014] Furthermore, the tea leaf juice obtained in step (1) can be prepared and used immediately or stored at low temperature. Storage at 4°C can effectively prevent the enzymatic oxidation degradation and oxidative loss of the substances contained in the tea leaves. It is generally recommended to prepare and use it immediately.

[0015] Furthermore, the amount of tea leaves used in step (2) is 0.5%-50% of the total weight of dry tea.

[0016] Furthermore, in step (2), the total amount of tide water and tea leaf juice added is 20%-60% of the weight of the raw material, wherein the amount of tea leaf juice added is 5%-60% of the weight of the raw material. If the amount of leaf juice added is too low, a higher concentration is required in step 1), which is not conducive to the crushing process of the tea leaves; if the amount of leaf juice added is too high, the tea pile is not moist enough, and the enzyme in the tea leaf juice may not survive after the tea leaf juice is added, resulting in a weakened effect.

[0017] Furthermore, during the fermentation process of step (2), starting from the second day after the tide, the temperature of the pile core is turned when it is lower than 30-35° C. The humidity during turning is 50%-90% and the piles are fully delumped and water is added to ensure that the fermentation is fully carried out.

[0018] Furthermore, in the fermentation process of step (2), water is added to the tea pile after the first turning of the pile until the water content of the tea pile is 40%±5%; water is added to the tea pile after the second turning of the pile until the water content of the tea pile is 35%±5%; water is added to the tea pile after the third turning of the pile until the water content of the tea pile is 35%±5%. On the one hand, the smooth progress of the pile fermentation is ensured, and on the other hand, the pile temperature is controlled to prevent the pile temperature from being too high or too low, and to reduce the generation of miscellaneous bacteria.

[0019] Furthermore, the drying method in step (3) includes one or a combination of air drying, air drying, sun drying, oven drying, vacuum freeze drying, and low temperature drying.

[0020] Furthermore, the Pu'er ripe tea product in step (3) can be further made into compressed tea through a cake pressing process.

[0021] The invention utilizes tea leaves to assist the pile fermentation of Pu'er tea, controls the fermentation tide volume, the pile turning cycle, the number of pile turnings, the amount of water added during the pile turning, and the amount of tea leaf juice added, and constantly monitors the main physical and chemical indicators of each stage in the Pu'er tea pile fermentation process, explores the change conditions and change rules thereof, so as to achieve the purpose of shortening the fermentation time of Pu'er tea and improving the quality of Pu'er cooked tea.

[0022] The beneficial effects of the present invention are:

[0023] (1) General exogenous additives, such as sugars, enzymes or inoculants, are not allowed to be used in the current Pu'er tea fermentation process. Tea leaves are rich in sugars, enzymes and other substances. As a natural exogenous additive, they can be added to the current Pu'er tea fermentation process. At the same time, tea leaf juice is the original environment of endogenous enzymes. The polysaccharides and other ingredients it contains have a protective and promoting effect on endogenous enzymes, enabling endogenous enzymes to better function in the pile environment.

[0024] (2) Tea leaves are easy to obtain and have low cost. Therefore, using tea leaves to assist the fermentation of Pu'er tea can not only reduce production costs and avoid the waste of tea resources in actual production, but also help reduce the fermentation time of Pu'er tea and improve the quality of tea.

[0025] (3) In terms of sensory evaluation, the Pu'er tea processed with tea leaves as exogenous additives has a bright red soup color, pure aroma, and mellow taste compared to the traditional Pu'er tea.

[0026] (4) Using tea leaves as exogenous additives to assist the fermentation of Pu'er tea can significantly reduce the content of biogenic amines in Pu'er ripe tea and improve the safety and quality of tea. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 , a flow chart of the tea leaf-assisted Pu'er tea pile fermentation of the present invention;

[0028] Figure 2 , temperature monitoring during the conventional and novel stacking processes of the present invention;

[0029] Figure 3 , comparison of liquid phase diagrams of traditional and novel pile-fermented Pu'er ripe tea of ​​the present invention;

[0030] Figure 4 , changes in tea polyphenols content during the traditional and new pile fermentation processes of the present invention. DETAILED DESCRIPTION

[0031] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0032] The following examples can be understood as a part of the local structure or method of the present invention alone, and can also be understood as the combination of the examples to explain the connotation of the larger structure or method of the present invention. Unless otherwise specified, all raw materials of the present invention are obtained from commercial sales.

[0033] Example 1: New type of pile fermentation

[0034] A method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0035] (1) Weigh 400 g of freshly picked green tea buds, put them into a tissue crusher, add water (about 1.0-1.2 kg) several times to crush the green tea buds to obtain a homogenate, filter through ordinary gauze of about 20 meshes to filter out the broken tea residue, and then store at low temperature.

[0036] (2) Take 4.0 kg of Yunnan large-leaf sun-dried green tea as fermentation raw material, wrap it with gauze and place it in a bamboo basket with a diameter of 48×35 cm, first spray it with 1.4 kg of water to make it evenly moist; then quickly add 1.4 kg of filtrate obtained in step (1) to prevent oxidation or store it at low temperature to prevent oxidation, put it into a spray pot, and spray it evenly with the spray pot to ensure that the tea sample is evenly wet. At this time, the water content of the tea pile is 43-44%.

[0037] Starting from the second day after the tide, the pile is turned every 4 to 7 days, and the pile is turned when the temperature of the core is lower than 35℃ (or by observing the state of the tea leaves on the outer layer of the pile). The first turning of the pile is carried out after 7 days, and the blocks are fully deblocked during turning. When turning the pile, add water according to the dryness of the tea leaves and ensure that the tea leaves are evenly moistened. At this time, the moisture content of the tea pile is about 40%. The second turning of the pile is carried out after 6 days. Before turning the pile, the temperature is kept at 35℃, and water is added to the moisture content of about 35%. The third turning of the pile is carried out after four days. Before turning the pile, the temperature is kept at 30℃, and water is added to the moisture content of about 35%. After the third turning of the pile, continue fermentation for 3 days.

[0038] (3) After the tea leaves are fermented, spread out all the tea leaves in a dark, cool and ventilated place to cool and dry. After 3 days, the ripe Pu'er tea can be harvested.

[0039] Comparative Example 1: Traditional Piling

[0040] In step (2), only 2.8 kg of water is sprayed as tide water, and no tea juice is sprayed separately. The rest is the same as in Example 1.

[0041] Verification results:

[0042] The determination methods of physical and chemical indicators are as follows:

[0043] The determination of catechins was carried out by high performance liquid chromatography: refer to GB / T 8313-2013. Specifically: accurately weigh 0.2g of sample, add 50mL of 70% methanol solution in a 70℃ water bath, stir thoroughly with a glass rod, and extract in a 70℃ water bath for 40min. Filter and cool with absorbent cotton, dilute the filtrate to 50mL with 70% methanol solution, take 3mL of the extract and centrifuge at 3500r / min for 10min, and the supernatant is filtered through a 0.45μm filter membrane for HPLC analysis.

[0044] Chromatographic conditions:

[0045] Chromatographic column: Agilent, HC-C18, 4.6×250 mm, 5 μm;

[0046] Mobile phase: Phase A: 90 mL acetonitrile, 20 mL acetic acid, 2 mL EDTA-2Na (10 mg / mL) dilute to 1000 mL;

[0047] Phase B: 800 mL acetonitrile, 20 mL acetic acid, 2 mL EDTA-2Na (10 mg / mL) and dilute to 1000 mL.

[0048] Flow rate: 1.0 mL / min;

[0049] Detector: Ultraviolet detector (UV);

[0050] Detection wavelength: 278nm;

[0051] Column temperature: 35°C;

[0052] Injection volume: 10 μL.

[0053] Elution gradient: 100% phase A for 10 min;

[0054] ↓

[0055] 100% phase A → 68% phase A, 32% phase B within 15 min;

[0056] ↓

[0057] 68% phase A, 32% phase B for 10 min;

[0058] ↓

[0059] 100% phase A was maintained for 5 min.

[0060] The determination of tea pigments was carried out by ethyl acetate extraction method:

[0061] (1) Preparation of test solution.

[0062] Prepare by weighing 3 g of tea sample and placing it in a 250 mL conical flask. Add 125 mL of boiling water and extract on a boiling water bath for 10 min. Shake the flask 1 to 2 times during the extraction process, filter while hot, and quickly cool to room temperature.

[0063] (2) Separation.

[0064] ①Put 30mL of test solution in a 60mL separatory funnel, add 30mL of ethyl acetate, shake for 5 minutes, let stand and separate the layers, and then release the lower water layer and the upper ethyl acetate layer. Theaflavins and part of thearubigins (SI type thearubigins) are dissolved in the ester layer, while most of thearubigins and theabrownins remain in the aqueous solution.

[0065] ② Take 2 mL of the ethyl acetate layer in ①, put it in a 25 mL volumetric flask, and add 95% ethanol to dilute to the scale (Solution A).

[0066] ③ Take 15mL of ethyl acetate solution, put it in a 30mL separatory funnel, add 1.5mL of 2.5% sodium bicarbonate solution, shake for 30s, and let it stand for stratification. The thearubigins originally dissolved in the ester layer will be washed out by the sodium bicarbonate solution, and the theaflavins left in the ester layer are theaflavins. Discard the sodium bicarbonate solution in the lower layer. Take 4mL of ethyl acetate solution and put it in a 25mL volumetric flask, and dilute to the mark with 95% ethanol (C solution).

[0067] ④ Take 2 mL of the first aqueous layer solution, put it in a 25 mL volumetric flask, add 2 mL of saturated oxalic acid solution and 6 mL of water, and then add 95% ethanol to dilute to the scale (D solution).

[0068] ⑤ Take 15mL of the test solution, put it in a 30mL separatory funnel, add 15mL of n-butanol, shake for 3min, and let it stand to separate. Theaflavins and thearubigins are both dissolved in the n-butanol in the upper layer, while theabrownins are left in the aqueous solution in the lower layer because they are insoluble in n-butanol. Discharge the lower aqueous solution, take 2mL of the aqueous solution, put it in a 25mL volumetric flask, add 2mL of saturated oxalic acid solution and 6mL of water, and then add 95% ethanol to dilute to the scale (Solution B).

[0069] (3) Colorimetry. Use a 721 spectrophotometer or other spectrophotometer, with 95% ethanol as a reference, and use a 1 cm colorimetric cell to measure the optical density E of each solution at 380 nm. A 、E B 、E C 、E D .

[0070] (4) Calculation of results

[0071]

[0072] In the above formula, 2.25 and 7.06 are conversion factors under this operating condition.

[0073] Verification results:

[0074] like Figure 2 As shown, temperature monitoring during the pile fermentation process is crucial to the pile fermentation of Pu'er tea. The temperature must be maintained at at least above 30°C for pile fermentation to proceed. The new type of Pu'er tea pile can be heated up earlier in the early stage to reach the appropriate temperature for pile fermentation, and in the later stage of fermentation it also completes the cooling process first to complete the pile fermentation.

[0075] like Figure 3 As shown, while the new type of pile-fermentation has a faster fermentation speed, the substances retained in it are almost the same as those of the traditional pile-fermentation Pu'er ripe tea. Most of the ester-type catechins have been removed, and the fermentation is relatively complete.

[0076] like Figure 4 As shown, tea polyphenols are the key factor in judging the pile fermentation of Pu'er tea. From the tea polyphenol content, it can be obviously seen that the tea polyphenols in the new pile fermentation Pu'er ripe tea oxidize faster and more thoroughly, that is, the fermentation speed of the new pile fermentation technology is faster.

[0077] Example 2: Novel fermentation

[0078] A method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0079] (1) Pile the sun-dried green tea leaves in a large bamboo basket with a diameter of about 2.0m and a height of 1.0m to ensure the height of the Pu'er tea pile. Set the initial tidal water volume to 20%. First add some water to ensure that the entire tea pile is evenly moistened to ensure the activity of the enzyme after the tea leaf juice is added. Then add the crushed and filtered tea leaf juice and turn the pile. Repeat several times to ensure that the juice contained in the tea leaves is mixed evenly in the tea pile. The solid-liquid ratio of the tea leaf juice used is 1:1, and the amount of juice added is consistent with the initial tidal water volume, that is, the solid-liquid ratio is 1:0.2. At the same time, set up a group of traditional fermentation groups, only add water for fermentation for comparison, and keep the same water content and turning time.

[0080] (2) The temperature of the workshop where Pu'er tea is pile-fermented is set between 20 and 28°C, the humidity is set between 70 and 75%, and ventilation is maintained in the Pu'er production workshop.

[0081] (3) Count from the tide. Turn the pile every 6 days to properly control the temperature and evenly ferment the Pu'er tea. When turning the pile, pay attention to fully disintegrate the tea lumps and add water to the pile according to the actual situation.

[0082] (4) The pile was turned seven times in total, and drying was completed three days after the seventh turning. Samples were taken during the turning of the pile, and the changes in the physical and chemical indicators of the tea pile were measured each time the pile was turned to monitor the fermentation degree of the tea pile, and to explore its changes and patterns.

[0083] (5) When fermentation is complete, place the tea leaves on a wooden rack in layers of bamboo dustpans to cool and dry. The workshop should be kept away from light, cool and well ventilated. After 3 days, the ripe Pu'er tea can be harvested.

[0084] Verification results:

[0085] Determination method of volatile flavor compounds in Pu'er tea:

[0086] Weigh 1.0g of sample into a 20mL SPME sample bottle, add 5mL boiling water, and add 2μL internal standard 2,4,6-trimethyl-pyridine solution (104mg / L), balance in a 70℃ water bath for 15min, adjust the speed to 200r / min, adsorb for 30min, and desorb at the injection port for 5min. The 50 / 30μm CAR / PDMS / DVB extraction fiber used in this experiment was aged at 250℃ for 15min. Chromatographic column: HP-5MS column (30m×0.25mm×0.25μm). Heating program: initial temperature is 40℃, hold for 2min, heat to 100℃ at 2℃ / min, hold for 2min; heat to 230℃ at 10℃ / min, hold for 5min. The injection port temperature is 250℃; the carrier gas is high-purity helium with a flow rate of 1mL / min. Non-split injection. Using the Agilent MSD ChemStation and NIST 17.L spectral library search data, substances with a match greater than 80% were selected as identification results. A 10 ppm standard solution of C7-C30 normal alkanes was prepared, and the retention index was calculated to complete the qualitative analysis of the compounds and calculate the retention index.

[0087] Table 1. Comparison of physical and chemical indicators of traditional fermented Pu'er ripe tea and new fermented Pu'er ripe tea in Example 2

[0088]

[0089]

[0090] While the new pile fermentation shortens the fermentation time, it also has advantages over the traditional pile fermentation in various physical and chemical indicators. For example, low water extract is a characteristic of Pu'er ripe tea, and the new pile fermentation Pu'er ripe tea has a higher water extract content. At the same time, the new pile fermentation Pu'er ripe tea has higher theabrownin and flavonoid content and a higher conversion rate of tea polyphenols, which are all proofs of the better quality of the new pile fermentation Pu'er ripe tea.

[0091] Table 2. Analysis of volatile flavor compounds of traditional fermented and novel fermented Pu'er cooked tea in Example 2

[0092]

[0093]

[0094]

[0095]

[0096] The detected flavor compounds show that there are significant differences in the volatile compound composition of the new-type Wo Pile Pu'er ripe tea and that of the traditional Wo Pile Pu'er ripe tea. Specifically, the new-type Wo Pile Pu'er ripe tea has higher content of floral, fruity and woody volatile compounds and a stronger flavor. In other words, the new-type Wo Pile Pu'er ripe tea has a better flavor.

[0097] Example 3: Novel fermentation

[0098] A method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0099] (1) Put the picked tea leaves into a large grinder for crushing, then mix with water to obtain tea leaf juice and put it into a spray barrel. The mass of the tea leaves used is about 5% of the sun-dried green tea, and the liquid-to-solid ratio of water is about 1:1.5.

[0100] (2) Pile the sun-dried green tea leaves in the Pu'er tea fermentation workshop to ensure that the height of the Pu'er tea pile is greater than 1m. Set the initial tidal volume to 60%. When the tidal volume is reached, first use half of the tidal volume of drinking water to evenly moisten the entire tea pile, and then spray half of the tidal volume of the above-mentioned tea leaf juice.

[0101] (3) The temperature of the workshop where Pu'er tea is pile-fermented is set between 20 and 28°C, the humidity is set between 70 and 75%, and ventilation is maintained in the Pu'er production workshop.

[0102] (4) Count from the tide. Turn the pile every 7 days to properly control the temperature of the pile and prevent it from being too high. On the other hand, it allows the Pu'er tea pile to ferment evenly. When turning the pile, pay attention to fully dissolving the tea lumps and add appropriate amount of water to the tea pile based on the experience of the staff.

[0103] (5) Samples were taken during each turning of the pile, and the changes in the physical and chemical indicators of the tea pile were measured each time the pile was turned to monitor the fermentation degree of the tea pile and explore its changes and patterns. The pile was turned six times in total during the entire fermentation process. The fermentation was considered complete about three days after the sixth turning, and the total fermentation time was about 45 days.

[0104] (6) When fermentation is complete, the tea leaves are placed on bamboo dustpans on wooden racks to dry. The workshop should be kept away from light, cool and well ventilated. After 3 days, the Pu'er ripe tea can be harvested.

[0105] Table 3. Physical and chemical indexes of traditional fermentation and new fermentation Pu'er ripe tea in Example 3

[0106]

[0107]

[0108] Under the initial process conditions of 60% tidal water volume, the role of tea leaf juice is still very effective, shortening the fermentation time while also improving the quality of Pu'er ripe tea.

[0109] Embodiment 4:

[0110] A method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0111] (1) Pile the sun-dried raw tea in the Pu'er tea fermentation workshop to ensure that the height of the Pu'er tea pile is greater than 1m. Set the initial tidal volume to 45%. In the first group of tidal water, first use half of the tidal volume of drinking water to evenly moisten the entire tea pile, and then spray half of the tidal volume of polyphenol oxidase extract (0.5%). The second group sprays half of the tidal volume of juice made from 10% of the weight of the raw tea leaves (concentration of 1:1 liquid to material ratio). The third group adds the normal tidal volume of water for fermentation.

[0112] (2) The temperature of the workshop where Pu'er tea is pile fermented is set at 25°C, the humidity is set at 80%, and ventilation is maintained in the Pu'er production workshop.

[0113] (3) Count from the tide. Turn the pile every 7 days to properly control the temperature of the pile and prevent it from being too high. On the other hand, it allows the Pu'er tea pile to ferment evenly. When turning the pile, pay attention to fully dissolving the tea lumps and add appropriate amount of water to the tea pile based on the staff's experience.

[0114] (4) Sampling was performed during each turning of the pile, and the changes in the physical and chemical indicators of the tea pile were measured each time the pile was turned to monitor the fermentation degree of the tea pile and explore its changes and patterns.

[0115] (5) When fermentation is complete, the tea leaves are placed on bamboo dustpans on wooden racks to dry. The workshop should be kept away from light, cool and well ventilated. After 3 days, the ripe Pu'er tea can be harvested.

[0116] Table 4 Comparison of the effects of polyphenol oxidase and tea leaf juice as external additives in Pu'er tea pile fermentation

[0117]

[0118]

[0119] As shown in the table above, the addition of polyphenol oxidase can significantly reduce the fermentation time, while increasing the conversion rate of tea polyphenols and reducing harmful components such as nitrite and biogenic amines in Pu'er cooked tea. However, polyphenol oxidase mainly acts on the oxidation of tea polyphenols in tea leaves to reduce the time of Pu'er tea pile fermentation. Compared with Pu'er cooked tea fermented with tea leaf juice, the beneficial components such as free amino acids and reducing sugars are less retained or not fully converted. At the same time, some antibacterial substances in tea leaves also contribute to fewer harmful components in Pu'er cooked tea. In addition, tea leaves also contain other endogenous enzymes, which also promote subsequent fermentation. In addition, the carbohydrates and other components contained in tea leaves are more conducive to protecting the activity of endogenous enzymes such as polyphenol oxidase and glycosidase, so that they can play a better role.

[0120] Embodiment 5:

[0121] A method for assisting the pile fermentation of Pu'er tea, comprising the following steps:

[0122] (1) Pile the sun-dried green tea leaves in the Pu'er tea fermentation workshop to ensure that the height of the Pu'er tea pile is greater than 1m. Set the initial tidal volume to 40%. At tidal time, first use half of the tidal volume of drinking water to evenly moisten the entire tea pile, then spray half of the tidal volume of polyphenol oxidase and glucose mixed solution (0.5% + 0.1%), add half of the tidal volume of glucose extract (0.1%) to the second group, spray half of the tidal volume of tea leaf juice with a material-liquid ratio of 1:15 to the third group, and the added material-liquid ratio is 1:0.2. The fourth group normally adds half of the tidal volume of water for fermentation.

[0123] (2) The temperature of the workshop where Pu'er tea is pile fermented is set at 25°C, the humidity is set between 75-80%, and the ventilation of the Pu'er production workshop is maintained.

[0124] (3) Count from the tide. Turn the pile every 7 days to properly control the temperature of the pile and prevent it from being too high. On the other hand, it allows the Pu'er tea pile to ferment evenly. When turning the pile, pay attention to fully dissolving the tea lumps and add appropriate amount of water to the tea pile based on the staff's experience.

[0125] (4) Sampling was performed during each turning of the pile, and the changes in the physical and chemical indicators of the tea pile were measured each time the pile was turned to monitor the fermentation degree of the tea pile and explore its changes and patterns.

[0126] (5) When fermentation is complete, the tea leaves are placed on bamboo dustpans on wooden racks to dry. The workshop should be kept away from light, cool and well ventilated. After 3 days, the ripe Pu'er tea can be harvested.

[0127] Table 5 Comparison of the effects of glucose, polyphenol oxidase and tea leaf juice as exogenous additives in Pu'er tea pile fermentation

[0128]

[0129] The addition of glucose can also effectively promote the fermentation of Pu'er tea, which exists as a carbon source for microorganisms, thereby promoting the fermentation of Pu'er tea. The cooked tea in the fermentation group with polyphenol oxidase and glucose added at the same time can more effectively promote the fermentation and significantly improve the conversion rate of tea polyphenols, which is already a very good auxiliary process. However, compared with the new fermentation of Pu'er cooked tea, the fermentation time is shorter, and the conversion rate of tea polyphenols is not much different. It has higher content of free amino acids, reducing sugars, water extracts, flavonoids and theabrownins, and the cost of tea leaf juice is much lower than that of glucose and polyphenol oxidase (for example: the price of polyphenol oxidase is 50mg / 850 yuan (source leaf, item number: S10171-25KU, specification: 500u / mg). Except for the tender buds, the other tea leaves cannot be made into tea, so there is almost no cost.), which is the advantage of the new fermentation.

[0130] In summary, the present invention mixes tea leaves with water and crushes them, and obtains tea leaf juice by filtering. Pu'er raw tea / raw tea is used as raw material, and tea leaf juice is sprayed at the beginning stage of pile fermentation. In the pile fermentation stage, the temperature and humidity of the tea pile are used as objective indicators to turn the pile and replenish water. After the pile fermentation is completed, the tea sample is dried to obtain a finished Pu'er cooked tea. Spraying is carried out at the beginning stage of the pile fermentation of Pu'er raw tea / raw tea to provide a material basis for the formation of Pu'er tea quality at this stage, thereby achieving the purpose of shortening the pile fermentation time and improving the quality of Pu'er tea. The present invention uses tea leaves to assist the pile fermentation of Pu'er tea, which can not only greatly shorten the pile fermentation time of Pu'er tea, but also improve the flavor and quality of Pu'er cooked tea, complete the high value of tea leaves, and has a good reference value for actual production.

Claims

1. A method for assisting the fermentation of Pu'er tea, characterized in that The following steps are involved: 1) Mixing freshly picked tea leaves with water and crushing them, filtering and obtaining tea leaf juice, wherein the solid-liquid ratio of the tea leaf juice is 1:1 to 1:10; 2) Use Pu'er raw tea / raw tea as raw material, add tide water first and then add the above tea leaf juice. 3) After the pile fermentation is completed, the tea leaves are dried to obtain the Pu'er cooked tea product.

2. The fermentation method according to claim 1, characterized in that: The tea leaves described in step (1) include tea buds, fresh tea leaves, old tea flakes, or a mixture of more than one of these.

3. The fermentation method according to claim 1, characterized in that: The crushing in step (1) is carried out by grinding, crushing with a tissue crusher or crushing with a wall breaking machine.

4. The method according to claim 1, characterized in that The amount of tea leaves in step 2) is 0.5%-50% of the total weight of dry tea.

5. The fermentation method according to claim 1, characterized in that: The tea leaf juice obtained in step (1) is used immediately after preparation or stored at low temperature.

6. The fermentation method according to claim 1 or 2, characterized in that: In step (2), the total amount of tidal water and tea leaf juice added is 20-60% of the weight of the raw material, wherein the amount of tea leaf juice added is 5%-60% of the weight of the raw material.

7. The fermentation method according to claim 3, characterized in that: The drying method in step (3) includes one or a combination of air drying, air drying, sun drying, oven drying, vacuum freeze drying, and low temperature drying.

8. The Pu'er ripe tea product as claimed in claim 3 can be further made into compressed tea through a cake pressing process.

Images