Polymorphic bio-enzyme preparation for improving dark tea quality and tea making process
Through the synergy of the immobilized polymorphic biological enzyme preparation and microbial fermentation agent, the problems of long fermentation cycle and unstable quality of black tea are solved, and the aroma and taste are improved, which is suitable for large-scale production.
Patent Information
- Application Number
- CN202411849930.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-18
AI Technical Summary
In the existing black tea preparation process, the fermentation cycle is long, the quality is unstable, and the effect of a single enzyme preparation is limited, making it difficult to effectively decompose tea tissue and release aromatic substances.
Using polymorphic biological enzyme preparation, the tannins, polysaccharide hydrolase, polyphenol oxidase and protease are immobilized by cross-linking-embedding-crosslinking, combined with Bacillus natto fermentation broth and high-temperature aroma-enhancing yeast fermentation broth, synergistically act on the rolling and pile fermentation process of black tea.
It shortens the fermentation cycle of black tea, improves the aroma and taste of tea, reduces astringency, improves the quality and stability of black tea, and is suitable for large-scale production.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of tea making, in particular to a polymorphic bioenzyme preparation and a tea making process for improving the quality of dark tea. Background Art
[0002] Dark tea has a long history in my country. In recent years, the dark tea market has gradually extended from the northwest region to the inland. Due to its effects on lowering blood sugar, blood pressure and cholesterol, drinking dark tea regularly can supplement the body's essential minerals and various vitamins, which is beneficial to the prevention and treatment of anemia. Therefore, it is popular among the public and has great market potential. However, the utilization rate of dark tea in my country is currently very low. Dark tea mainly produces various aromatic substances through fermentation, thus producing a unique flavor. How to shorten the fermentation cycle of dark tea and remove bad flavors such as mold, roughness and sourness during the processing of dark tea is the current focus of dark tea processing, and is of great significance to the promotion of the dark tea market in the future.
[0003] Dark tea is a fully fermented tea, and its tea-making process generally includes the steps of withering, rolling, and pile fermentation. The essence of pile fermentation is to use the ingredients of sun-dried raw tea as the matrix, and undergo a series of biochemical reactions under the action of moisture, heat and enzymes to form the unique quality of dark tea. However, the activity of microorganisms in fresh dark tea leaves is inhibited and the action of intracellular enzymes is greatly passivated after the sun-drying process. In modern dark tea processing, the pile fermentation process takes about 27-35 days, and the degree of fermentation is manually controlled. In addition, traditional tea-making technology is difficult to guarantee the stability of dark tea quality, and the aroma and taste of tea may change due to fermentation conditions, time and other factors. Therefore, shortening the fermentation cycle, improving tea quality and realizing the standardization of the dark tea industry have become the current research focus of the dark tea industry.
[0004] In the tea-making process of dark tea, biological enzyme preparations can catalyze chemical reactions in tea leaves, accelerate the fermentation process, and improve the quality of tea leaves. In the prior art, single enzyme preparations are generally added, such as β-glucosidase, cellulase, etc. However, the effect of single enzyme preparations is limited and cannot effectively decompose tea tissues to release aroma substances; polymorphic biological enzyme preparations refer to complex enzyme preparations containing multiple enzymes, which can work synergistically to improve catalytic efficiency. For example, enzymes such as pectin hydrolase, β-glucanase, β-glucosidase and β-xylosidase are combined to decompose pectin, Macromolecular substances such as glucan, glucoside and xyloside can reduce the astringency of tea and improve the aroma and taste of tea; however, since enzymes are generally unstable to heat, strong acid, strong alkali, organic solvents, etc., enzymes usually act on substrates in aqueous solution, so enzymes can only be used once, and some enzymes are expensive in the market and have low efficiency; in addition, simply adding exogenous enzymes has limited effect, and microbial fermentation agents can easily decompose and utilize glycoside aroma precursors in tea leaves under the action of microorganisms through the reproduction of microorganisms themselves, thereby effectively improving the quality of black tea. The present invention aims to solve the problems in the above-mentioned black tea preparation process by immobilizing polymorphic enzymes and compounding them with microbial fermentation agents, and through the synergistic effect of enzyme preparations and fermentation agents, which has positive significance for solving the unsalable low-end tea and the comprehensive utilization of black tea. Summary of the invention
[0005] In view of this, the purpose of the present invention is to provide a polymorphic bioenzyme preparation and tea making process for improving the quality of black tea, which is beneficial to increase the aroma of black tea, solve the problem of bitterness of black tea and greatly improve the quality of black tea.
[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:
[0007] A tea-making process of a polymorphic bioenzyme preparation for improving the quality of dark tea is carried out according to the following steps:
[0008] Step (1), spreading: fresh dark tea leaves without disease or insect pests are selected, and spread for 8-16 hours at a temperature of 30-40° C., a humidity of 80-95%, and a pH of 4.5-5.0, followed by a withering treatment.
[0009] Step (2), rolling: after the dark tea is cooled, it is loaded into a rolling machine, sprayed evenly with a polymorphic enzyme preparation, and then rolled; the rolling time is 10-20 minutes, the pH is 4.5-6, and the temperature is 50-60°C.
[0010] Step (3), pile fermentation: spray the rolled dark tea evenly with the polymorphic enzyme preparation, and pile fermentation for 7-10 days under the conditions of humidity of 80-90% and pH of 4.0-5.0, with the temperature at the center of the tea pile being 40-60°C.
[0011] Step (4), drying: drying the piled dark tea at 80-100°C for 60-90 minutes, and then roasting until the water content of the tea leaves is 5%, and then cooling the tea leaves to room temperature.
[0012] Furthermore, in step (1), the fixing temperature is 240-300° C., and the fixing time is 2-5 min.
[0013] Furthermore, in step (2), the ratio of the polymorphic enzyme preparation to dark tea is (10-30) mL: 100 g.
[0014] Furthermore, in step (3), the ratio of the polymorphic enzyme preparation to dark tea is (5-9) mL: 100 g.
[0015] Furthermore, the preparation process of the polymorphic enzyme preparation in step (2) is carried out according to the following steps:
[0016] Step S1, adding tannase, polysaccharide hydrolase, polyphenol oxidase and protease to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after fully mixing, adding a 2.5% glyoxal aqueous solution, oscillating on an oscillator for 0.5-1h, standing at room temperature for cross-linking for 3-6h, injecting a 2% calcium chloride aqueous solution with a needle, filtering out small spheres, soaking and hardening for 1-2h, and then adding a 0.05% glyoxal aqueous solution, cross-linking at 5-10°C for 2-5h, filtering, and storing in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0017] Step S2: the concentration is 2.25×10 6 The natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL are added to the immobilized polymorphic enzyme preparation in step S1, cultured on a shaker at 35-45° C. and 100-150 r / min for 5-7 days, and centrifuged to obtain a polymorphic enzyme preparation.
[0018] Furthermore, in step S1, the polysaccharide hydrolase is any one of cellulase, pectinase, β-glucosidase or amylase.
[0019] Furthermore, in step S1, the mass concentration of tannase, polysaccharide hydrolase, polyphenol oxidase and protease is 0.1-0.2 mg / L.
[0020] Furthermore, in step S2, the centrifugal treatment speed is 3500-4500 r / min, and the centrifugal treatment time is 10-20 min.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] (1) Tannase, polysaccharide hydrolase, polyphenol oxidase and protease are immobilized through a cross-linking-embedding-cross-linking process, which improves the thermal stability and storage stability of the enzymes, enables fermentation at higher temperatures, and increases the content of aroma substances such as β-linalool, geranyl acetone and dihydroactin during the fermentation process, thereby solving the problem of bitterness of black tea; the process is simple and easy to operate, and is suitable for large-scale production.
[0023] (2) Under the action of polymorphic enzyme preparations, rolling, enzymatic hydrolysis and fermentation processes are carried out simultaneously, which not only reduces the time required for tea making, but also maintains the color of fresh leaves, reduces the astringency of tea leaves, ensures the full hydrolysis of proteins and polysaccharides, and ensures the extraction rate of amino acids; under the combined action of polymorphic enzyme preparations, natto Bacillus fermentation liquid, and high-temperature aroma-enhancing yeast fermentation liquid, the time required for pile fermentation is greatly reduced. The 7-10 days of pile fermentation time is only one-fourth of the time required by traditional techniques, which can better control the degree of fermentation and save production costs.
[0024] (3) During the fermentation process, Bacillus natto can produce a variety of enzymes, such as cellulase and pectinase, which can decompose macromolecular substances in tea leaves, such as cellulose and pectin, thereby promoting the fermentation process of tea leaves; high-temperature aroma-enhancing yeast can be active at higher temperatures, which helps to accelerate the fermentation process of dark tea. By consuming sugar and other nutrients in tea leaves, it produces carbon dioxide, alcohol and other volatile compounds, thereby enhancing the aroma and taste of dark tea.
[0025] (4) The tea soup brewed from tea treated with polymorphic enzyme preparations has improved clarity, less bitterness, better color and aroma, which is better than the effect of using a single enzyme treatment, and has less impact on the nutrition and taste of the tea. In addition, it has high safety, good effect and stable product quality, which is conducive to the development of tea products with unique flavors and different functions. DETAILED DESCRIPTION
[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0027] Unless otherwise stated, the exogenous enzymes and reagents used in this application are commercially available or can be prepared by known methods.
[0028] Preparation of natto Bacillus subtilis fermentation broth: The preserved natto Bacillus subtilis (preservation number: bio-33691, purchased from China Industrial Microbiological Culture Collection Management Center) was made into a suspension with sterile physiological saline, inoculated into a liquid fermentation medium and cultured and fermented for 18-24 hours to obtain natto Bacillus subtilis fermentation broth.
[0029] Preparation of high temperature flavoring yeast fermentation broth: The preserved high temperature flavoring yeast (also known as abnormal Hansen yeast, preservation number: bio-57911, purchased from the China Industrial Microbiological Culture Collection Management Center) is made into a suspension with sterile physiological saline, inoculated into a liquid fermentation medium and cultured and fermented for 18-24 hours to obtain the high temperature flavoring yeast fermentation broth.
[0030] Example 1
[0031] (1) Tannin, cellulase, polyphenol oxidase and protease with a mass concentration of 0.1 mg / L were added to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 0.8 h, and allowed to stand for crosslinking at room temperature for 5 h. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and the spheres were soaked and hardened for 1.5 h. A 0.05% glyoxal aqueous solution was then added, and the mixture was crosslinked at 6° C. for 3 h, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0032] (2) 2 mL of a concentration of 2.25×10 6 The natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth were added to the immobilized polymorphic enzyme preparation, cultured on a shaker at 40°C and 120 r / min for 6 days, and centrifuged at 4000 r / min for 15 minutes to obtain the polymorphic biological enzyme preparation.
[0033] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 12 hours at a temperature of 35°C, a humidity of 85%, and a pH of 4.6, and then wither at 270°C for 3 minutes.
[0034] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 10 mL:100 g, and then rolled; the rolling time is 15 min, the pH is 5.0, and the temperature is 55°C.
[0035] (5) Piling: Spray the rolled dark tea evenly with polymorphic enzyme preparation, where the solid-liquid ratio of polymorphic enzyme preparation to dark tea is 5 mL:100 g. Piling is carried out for fermentation for 7 days at a humidity of 85% and a pH of 4.5, with the temperature at the center of the tea pile being 50°C.
[0036] (6) Drying: Dry the piled dark tea at 90°C for 80 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0037] Example 2
[0038] (1) Tanninase, pectinase, polyphenol oxidase and protease with a mass concentration of 0.12 mg / L were added to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 0.5 h, and allowed to stand for crosslinking at room temperature for 3 h. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and soaked and hardened for 1 h. A 0.05% glyoxal aqueous solution was then added, and the mixture was crosslinked at 10° C. for 2 h, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0039] (2) 2 mL of a concentration of 2.25×10 6 Bacillus natto fermentation broth and high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL were added to the immobilized polymorphic enzyme preparation, cultured on a shaker at 45°C and 150 r / min for 5 days, and centrifuged at 4500 r / min for 10 min to obtain a polymorphic biological enzyme preparation.
[0040] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 8 hours at a temperature of 40°C, a humidity of 95%, and a pH of 5.0, and then wither at 300°C for 2 minutes.
[0041] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 15 mL:100 g, and then rolled; the rolling time is 10 min, the pH is 6, and the temperature is 60°C.
[0042] (5) Piling: The rolled dark tea is evenly sprayed with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 6 mL:100 g. The tea is piled and fermented for 8 days at a humidity of 90% and a pH of 5.0, with the temperature at the center of the tea pile being 60°C.
[0043] (6) Drying: Dry the piled dark tea at 100°C for 60 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0044] Example 3
[0045] (1) Tannase, β-glycosidase, polyphenol oxidase and protease with a mass concentration of 0.15 mg / L were added to a 3% sodium alginate aqueous solution according to a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 1 hour, and allowed to stand for cross-linking at room temperature for 6 hours. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and the spheres were soaked and hardened for 2 hours. A 0.05% glyoxal aqueous solution was then added, and the mixture was cross-linked at 5° C. for 5 hours, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0046] (2) 2 mL of a concentration of 2.25×10 6 Bacillus natto fermentation broth and high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL were added to the immobilized polymorphic enzyme preparation, cultured on a shaker at 35°C and 100 r / min for 7 days, and centrifuged at 3500 r / min for 20 min to obtain a polymorphic biological enzyme preparation.
[0047] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 16 hours at a temperature of 30°C, a humidity of 80%, and a pH of 4.5, and then wither at 240°C for 5 minutes.
[0048] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 20 mL:100 g, and then rolled; the rolling time is 20 min, the pH is 4.5, and the temperature is 50°C.
[0049] (5) Piling: Spray the rolled dark tea evenly with polymorphic enzyme preparation, where the solid-liquid ratio of polymorphic enzyme preparation to dark tea is 7 mL:100 g. Piling is carried out for 10 days at a humidity of 80% and a pH of 4.0, with the temperature at the center of the tea pile being 40°C.
[0050] (6) Drying: Dry the piled dark tea at 80°C for 90 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0051] Example 4
[0052] (1) Tannin, amylase, polyphenol oxidase and protease with a mass concentration of 0.18 mg / L were added to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 0.6 h, and allowed to stand for cross-linking at room temperature for 4 h. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and the spheres were soaked and hardened for 2 h. A 0.05% glyoxal aqueous solution was added, and the mixture was cross-linked at 8° C. for 3 h, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0053] (2) 2 mL of a concentration of 2.25×10 6 The natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth were added to the immobilized polymorphic enzyme preparation, cultured on a shaker at 40°C and 150 r / min for 6 days, and centrifuged at 4200 r / min for 18 minutes to obtain the polymorphic biological enzyme preparation.
[0054] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 15 hours at a temperature of 32°C, a humidity of 88%, and a pH of 4.8, and then wither at 260°C for 5 minutes.
[0055] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 25 mL:100 g, and then rolled; the rolling time is 16 min, the pH is 5.5, and the temperature is 60°C.
[0056] (5) Piling: The rolled dark tea is evenly sprayed with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 8 mL:100 g. The tea is piled and fermented for 9 days at a humidity of 85% and a pH of 5.0, with the temperature at the center of the tea pile being 55°C.
[0057] (6) Drying: Dry the piled dark tea at 95°C for 85 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0058] Example 5
[0059] (1) Tannase, cellulase, polyphenol oxidase and protease with a mass concentration of 0.2 mg / L were added to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 1 hour, and allowed to stand for crosslinking at room temperature for 5 hours. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and the spheres were soaked and hardened for 2 hours. A 0.05% glyoxal aqueous solution was then added, and the mixture was crosslinked at 5° C. for 4 hours, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0060] (2) 2 mL of a concentration of 2.25×10 6 Bacillus natto fermentation broth and high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL were added to the immobilized polymorphic enzyme preparation, cultured on a shaker at 45°C and 135 r / min for 7 days, and centrifuged at 3800 r / min for 16 min to obtain a polymorphic biological enzyme preparation.
[0061] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 12 hours at a temperature of 35°C, a humidity of 90%, and a pH of 4.5, and then wither them at 280°C for 3 minutes.
[0062] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 30 mL:100 g, and then rolled; the rolling time is 20 min, the pH is 5, and the temperature is 50°C.
[0063] (5) Piling: The rolled dark tea is evenly sprayed with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 9 mL:100 g. The tea is piled and fermented for 10 days at a humidity of 90% and a pH of 4.5, with the temperature at the center of the tea pile being 45°C.
[0064] (6) Drying: Dry the piled dark tea at 90°C for 90 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0065] Comparative Example 1
[0066] (1) Tannase, cellulase, polyphenol oxidase and protease with a mass concentration of 0.1 mg / L were mixed in a volume ratio of 2:3:3:2 to obtain a polymorphic enzyme preparation.
[0067] (2) 2 mL of a concentration of 2.25×10 6 The natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth were added to the polymorphic enzyme preparation, cultured on a shaker at 40°C and 120 r / min for 6 days, and centrifuged at 4000 r / min for 15 minutes to obtain the polymorphic biological enzyme preparation.
[0068] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 12 hours at a temperature of 35°C, a humidity of 85%, and a pH of 4.6, and then wither at 270°C for 3 minutes.
[0069] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with a polymorphic enzyme preparation, wherein the solid-liquid ratio of the polymorphic enzyme preparation to the dark tea is 10 mL:100 g, and then rolled; the rolling time is 15 min, the pH is 5.0, and the temperature is 55°C.
[0070] (5) Piling: Spray the rolled dark tea evenly with polymorphic enzyme preparation, where the solid-liquid ratio of polymorphic enzyme preparation to dark tea is 5 mL:100 g. Piling is carried out for fermentation for 7 days at a humidity of 85% and a pH of 4.5, with the temperature at the center of the tea pile being 50°C.
[0071] (6) Drying: Dry the piled dark tea at 90°C for 80 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0072] Comparative Example 2
[0073] (1) Tannin, cellulase, polyphenol oxidase and protease with a mass concentration of 0.1 mg / L were added to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after being fully mixed, a 2.5% glyoxal aqueous solution was added, and the mixture was oscillated on an oscillator for 0.8 h, and allowed to stand for crosslinking at room temperature for 5 h. A 2% calcium chloride aqueous solution was injected with a needle, and the small spheres were filtered out, and the spheres were soaked and hardened for 1.5 h. A 0.05% glyoxal aqueous solution was then added, and the mixture was crosslinked at 6° C. for 3 h, filtered, and stored in a refrigerator to obtain an immobilized polymorphic enzyme preparation.
[0074] (2) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 12 hours at a temperature of 35°C, a humidity of 85%, and a pH of 4.6, and then wither them at 270°C for 3 minutes.
[0075] (3) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with the immobilized polymorphic enzyme preparation, wherein the solid-liquid ratio of the immobilized polymorphic enzyme preparation to the dark tea is 10 mL:100 g, and then rolled; the rolling time is 15 min, the pH is 5.0, and the temperature is 55°C.
[0076] (4) Piling: Spray the rolled dark tea evenly with the immobilized polymorphic enzyme preparation, wherein the solid-liquid ratio of the immobilized polymorphic enzyme preparation to the dark tea is 5 mL:100 g. Piling is carried out for fermentation for 7 days at a humidity of 85% and a pH of 4.5, and the temperature at the center of the tea pile is 50°C.
[0077] (5) Drying: Dry the piled dark tea at 90°C for 80 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0078] Comparative Example 3
[0079] (1) Add 0.1 mg / L tannase to 3% sodium alginate aqueous solution, mix thoroughly, add 2.5% glyoxal aqueous solution, shake on an oscillator for 0.8 h, stand at room temperature for cross-linking for 5 h, inject 2% calcium chloride aqueous solution with a needle, filter out small spheres, soak and harden for 1.5 h, then add 0.05% glyoxal aqueous solution, cross-link at 6° C. for 3 h, filter, and store in a refrigerator to obtain an immobilized enzyme preparation.
[0080] (2) 2 mL of a concentration of 2.25×10 6 Bacillus natto fermentation broth and high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL were added to the immobilized enzyme preparation, cultured on a shaker at 40°C and 120 r / min for 6 days, and centrifuged at 4000 r / min for 15 min to obtain the bioenzyme preparation.
[0081] (3) Spreading: Select fresh dark tea leaves without diseases and insect pests, spread them for 12 hours at a temperature of 35°C, a humidity of 85%, and a pH of 4.6, and then wither at 270°C for 3 minutes.
[0082] (4) Rolling: After the dark tea leaves are cooled, they are loaded into a rolling machine and sprayed evenly with the bio-enzyme preparation, wherein the solid-liquid ratio of the polymorphic bio-enzyme preparation to the dark tea is 10 mL:100 g, and then rolled; the rolling time is 15 min, the pH is 5.0, and the temperature is 55°C.
[0083] (5) Piling: Spray the rolled dark tea evenly with a polymorphic bioenzyme preparation, where the solid-liquid ratio of the bioenzyme preparation to the dark tea is 5 mL:100 g. Piling is carried out for fermentation for 7 days at a humidity of 85% and a pH of 4.5, with the temperature at the center of the tea pile being 50°C.
[0084] (6) Drying: Dry the piled dark tea at 90°C for 80 minutes, then roast it until the moisture content of the tea leaves is 5%, and then cool it down to room temperature.
[0085] Comparative Example 4
[0086] The difference between this comparative example and comparative example 3 is that in step (1), cellulase is used instead of tannase, and other conditions remain the same.
[0087] Comparative Example 5
[0088] The difference between this comparative example and comparative example 3 is that polyphenol oxidase is used instead of tannase in step (1), and other conditions remain the same.
[0089] Comparative Example 6
[0090] The difference between this comparative example and comparative example 3 is that in step (1), protease is used instead of tannase, and other conditions remain the same.
[0091] Comparative Example 7
[0092] The difference between this comparative example and Example 1 is that the polymorphic bioenzyme preparation, the natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth are not added, and other conditions remain the same.
[0093] Tea polyphenols detection method: refer to method 2 in GB / T 8313-2008 "Determination of tea polyphenols and catechins in tea" for testing.
[0094] Amino acid detection method: Test according to GB / T 8314-2013 "Determination of the total amount of free amino acids in tea".
[0095] Soluble sugar detection method: Anthrone colorimetric method is used for testing.
[0096] Table 1 Dark tea extract composition test
[0097]
[0098]
[0099] Tea polyphenols are the main flavoring substances in tea and are the general term for a variety of phenolic substances. The main active substance is catechins, which account for about 70% of the total tea polyphenols. They taste bitter and have strong astringency. They are the main substances that constitute bitterness, sweetness and the production of body fluids. With the increase of the content of polymorphic enzyme preparations and the addition of fermentation liquid, the content of tea polyphenols gradually decreases. This is because during the fermentation process of dark tea, polyphenols are oxidized and condensed under the action of polymorphic enzyme biological preparations, while driving the oxidation of other substances, thereby changing the taste of the tea soup from bitter to mellow, and converting them into colored substances such as theaflavins and thearubigins, which can quickly reduce the content of catechins with astringency and bitterness in the tea sample, making the flavor of the tea sample tend to be mellow and faster to transform into similar dark tea flavor quality characteristics.
[0100] The amino acid degradation of black tea with the addition of polymorphic enzyme biological preparations is not large, and there is even an upward trend. This is because Bacillus natto can produce a variety of enzymes during the fermentation process, such as cellulase, pectinase, etc. These enzymes can decompose large molecular substances in tea, such as cellulose, pectin, etc., thereby promoting the fermentation process of tea. The extracellular enzymes secreted by the fermentation liquid work together with the polymorphic enzyme biological preparations to hydrolyze proteins to produce some essential amino acids for the human body, such as lysine, phenylalanine, leucine, etc. The content of these amino acids may gradually increase, further promoting the conversion of amino acids in tea, generating substances with special flavor and aroma, and improving the quality of black tea.
[0101] Bacillus natto secretes a large amount of extracellular enzymes that help decompose insoluble sugars into soluble sugars, causing the total sugar content to show an upward trend; cellulase, pectinase, etc. in polymorphic enzyme preparations can decompose insoluble polysaccharides such as cellulose and pectin in tea leaves, converting them into soluble sugars, thereby increasing the soluble sugar content in black tea. The various enzymes in the polymorphic enzyme work synergistically to help decompose insoluble sugars into soluble sugars, causing the total sugar content to show an upward trend, which can promote the formation of specific sugars in tea leaves and improve the bitter and unpleasant flavor of black tea. Black tea has a unique sweetness and aroma.
[0102] Aroma component test: The aroma components in the tea leaves obtained in each example were tested using headspace solid phase microextraction-gas chromatography-mass spectrometry.
[0103] Table 2 Aroma component test
[0104]
[0105] β-linalool, geranylacetone and dihydroactinol are important alcohol, ketone and ester aroma substances in dark tea, respectively. After the polymorphic enzyme was subjected to the cross-linking-embedding-cross-linking immobilization operation in Examples 1-5, the contents of the three aroma substances were all increased, indicating that the thermal stability and storage stability of the polymorphic enzyme were improved after the immobilization operation; in Comparative Example 1, the polymorphic enzyme was not subjected to the cross-linking-embedding-cross-linking immobilization operation, so it was more easily affected by the pile fermentation temperature, resulting in less aroma components in the dark tea; in Comparative Example 2, high-temperature aroma-enhancing yeast fermentation broth was not added, which not only can affect the conversion and accumulation of tea polyphenols, theabrownins and other substances in tea leaves, but also can produce volatile substances including alcohols, esters, ketones, etc., which together constitute the unique aroma characteristics of dark tea; in Comparative Examples 3-6, a single enzyme was added, and its effect was limited; in Comparative Example 7, no exogenous enzyme and fermentation broth were added, and the quality of dark tea was the worst.
[0106] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.
Claims
1. A polymorphic enzyme preparation for improving the quality of dark tea, characterized in that: The preparation process of the polymorphic biological enzyme preparation is carried out according to the following steps: Step S1, adding tannase, polysaccharide hydrolase, polyphenol oxidase and protease to a 3% sodium alginate aqueous solution in a volume ratio of 2:3:3:2, and after fully mixing, adding a 2.5% glyoxal aqueous solution, oscillating on an oscillator for 0.5-1h, standing at room temperature for cross-linking for 3-6h, injecting a 2% calcium chloride aqueous solution with a needle, filtering out small spheres, soaking and hardening for 1-2h, and then adding a 0.05% glyoxal aqueous solution, cross-linking at 5-10°C for 2-5h, filtering, and storing in a refrigerator to obtain an immobilized polymorphic enzyme preparation; Step S2: the concentration is 2.25×10 6 The natto Bacillus subtilis fermentation broth and the high-temperature flavoring yeast fermentation broth with a concentration of 100 g / mL are added to the immobilized polymorphic enzyme preparation in step S1, cultured on a shaker at 35-45° C. and 100-150 r / min for 5-7 days, and centrifuged to obtain a polymorphic enzyme preparation.
2. The polymorphic enzyme preparation for improving the quality of dark tea according to claim 1, characterized in that: The polysaccharide hydrolase in step S1 is any one of cellulase, pectinase, β-glucosidase or amylase.
3. The polymorphic enzyme preparation for improving the quality of dark tea according to claim 1, characterized in that: The mass concentration of tannase, polysaccharide hydrolase, polyphenol oxidase and protease in step S1 is 0.1-0.2 mg / L.
4. The polymorphic enzyme preparation for improving the quality of dark tea according to claim 1, characterized in that: In step S2, the centrifugal treatment speed is 3500-4500 r / min, and the centrifugal treatment time is 10-20 min.
5. The use of the polymorphic enzyme preparation for improving the quality of dark tea in a tea making process according to any one of claims 1 to 4, characterized in that: The tea making process comprises the following steps: Step (1), spreading: selecting fresh dark tea leaves without diseases and insect pests, spreading them for 8-16 hours at a temperature of 30-40°C, a humidity of 80-95%, and a pH of 4.5-5.0, and then performing a withering treatment; Step (2), rolling: after the dark tea leaves are cooled, they are loaded into a rolling machine, sprayed evenly with the polymorphic enzyme preparation, and then rolled; the rolling time is 10-20 minutes, the pH is 4.5-6, and the temperature is 50-60°C; Step (3), pile fermentation: spray the rolled dark tea evenly with the polymorphic enzyme preparation, and pile fermentation for 7-10 days under the conditions of humidity of 80-90% and pH of 4.0-5.0, with the temperature at the center of the tea pile being 40-60° C.; Step (4), drying: drying the piled dark tea at 80-100°C for 60-90 minutes, and then roasting until the water content of the tea leaves is 5%, and then cooling the tea leaves to room temperature.
6. The use of the polymorphic enzyme preparation for improving the quality of dark tea according to claim 5 in a tea making process, characterized in that: In the step (1), the killing temperature is 240-300° C., and the killing time is 2-5 min.
7. The use of the polymorphic enzyme preparation for improving the quality of dark tea in a tea making process according to claim 5, characterized in that: In the step (2), the ratio of the polymorphic enzyme preparation to dark tea is (10-30) mL: 100 g.
8. The use of the polymorphic enzyme preparation for improving the quality of dark tea in the tea making process according to claim 5, characterized in that: In the step (3), the ratio of the polymorphic enzyme preparation to dark tea is (5-9) mL: 100 g.