Osmanthus black tea and preparation method thereof

Abstract

The invention relates to sweet-scented osmanthus black tea and a preparation method thereof, and belongs to the technical field of tea beverages. The preparation method specifically comprises the following steps: S1, performing primary homogenization, separation, concentration and secondary homogenization on black tea to obtain a black tea solution; s2, adding a sucrose solution, a sweet-scented osmanthus extracting solution and a lactic acid bacteria seed solution into the black tea solution, and performing fermentation to obtain a compound fermentation solution; and S3, adding a yeast seed solution into the compound fermentation solution, and performing fermentation and sterilization to obtain the sweet-scented osmanthus black tea. The flavor, the biological activity and the nutritional value of the sweet osmanthus black tea can be remarkably improved through high-pressure homogenization, ultrahigh-pressure homogenization, saccharomycetes and lactic acid bacteria step-by-step fermentation.

Description

Technical Field

[0001] The invention belongs to the technical field of tea beverages, and in particular relates to osmanthus black tea and a preparation method thereof. Background Art

[0002] Black tea is one of the six major tea varieties in my country. It is made from new leaves of suitable tea trees and refined through a series of processes such as withering, rolling (cutting), fermentation, and drying. Black tea is named because the tea soup and leaf base color after the dry tea is brewed are red.

[0003] Black tea is the world's largest-produced and most consumed tea, accounting for about 80% of the world's total tea trade. However, the taste of existing black tea is average, and the starch and protein rich in black tea cannot be effectively utilized, which limits the market appeal and competitiveness of black tea.

[0004] Therefore, how to prepare a black tea with good taste and high nutritional value is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an osmanthus black tea and a preparation method thereof.

[0006] The first object of the present invention is to provide a method for preparing osmanthus black tea, which specifically comprises the following steps:

[0007] S1, homogenizing, separating, concentrating, and homogenizing twice the black tea to obtain a black tea solution;

[0008] S2, adding sucrose solution, osmanthus extract and yeast seed solution to the black tea solution described in S1, and fermenting to obtain a composite fermentation liquid;

[0009] S3, adding lactic acid bacteria seed liquid to the composite fermentation liquid described in S2, and obtaining the osmanthus black tea through fermentation and sterilization.

[0010] In one embodiment of the present invention, in S1, the primary homogenization is performed at 100Mpa-200Mpa for 10min-30min.

[0011] In one embodiment of the present invention, in S1, the concentration level is 1-3.

[0012] In one embodiment of the present invention, in S1, the secondary homogenization is performed at 400Mpa-500Mpa for 5min-15min.

[0013] In one embodiment of the present invention, in S2, the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:(0.6-0.8):(0.3-0.5).

[0014] In one embodiment of the present invention, in S2, the yeast is Saccharomyces cerevisiae; the concentration of the yeast seed solution is 10 6 -10 8 CFU / mL; the volume fraction of the yeast seed liquid is 1.5%-2.5%.

[0015] In one embodiment of the present invention, in S3, the lactic acid bacteria is Lactobacillus plantarum; the concentration of the lactic acid bacteria seed liquid is 10 6 -10 8 CFU / mL; the volume fraction of the lactic acid bacteria seed liquid is 2%-3%.

[0016] In one embodiment of the present invention, in S3, the sterilization is performed at 80°C-90°C for 20min-30min.

[0017] In one embodiment of the present invention, in S2 and S3, the fermentation is independently carried out at 29° C.-31° C. for 24 h-72 h.

[0018] The second object of the present invention is to provide an osmanthus black tea prepared by the method described above.

[0019] The technical solution of the present invention has the following advantages over the prior art:

[0020] (1) The preparation method of the present invention first changes the structure of nutrients such as starch, cellulose and protein from a physical level through primary homogenization to promote dissolution. Secondary homogenization is to modify the concentrated nutrients. Ultra-high pressure changes the structure of nutrients, destroys non-covalent bonds such as hydrogen bonds, ionic bonds and hydrophobic bonds in nutrients, increases the polarity of nutrients, increases solubility, and greatly improves the utilization rate of nutrients.

[0021] (2) The preparation method of the present invention first hydrolyzes sucrose into glucose and fructose by yeast, and further ferments fructose to produce ethanol. When the glucose in the fermentation liquid reaches a certain value, lactic acid bacteria are introduced to convert glucose into lactic acid. In addition, nutrients such as starch, cellulose and protein in black tea can promote the growth and reproduction of yeast, and the lactic acid bacteria in the system can use some metabolites of yeast to grow and reproduce, and produce a certain amount of lactic acid.

[0022] (3) The step-by-step fermentation process described in the present invention can enhance the flavor and color of black tea by adding osmanthus extract and yeast, solve the problem of bad flavor of black tea, and give black tea a mellow flavor and natural and simple color. The addition of yeast can reduce the total acid content of the system, achieving the purpose of reducing acid. Lactic acid bacteria can produce a large amount of lactic acid and amino acids through metabolism, which is conducive to the growth of yeast. In addition, the step-by-step fermentation process can produce flavor substances such as alcohol esters, which synergistically enhance the flavor of osmanthus black tea.

[0023] (4) The preparation method of the present invention converts the polyphenols in black tea into free forms with more hydroxyl groups through step-by-step fermentation, thereby significantly enhancing the antioxidant activity of the beverage. Phenolic substances are aromatic rings containing hydroxyl groups, which play an antioxidant role by scavenging free radicals, chelating metal ions and inhibiting oxidase activity. Therefore, the flavor, biological activity and nutritional value of osmanthus black tea can be significantly improved through high-pressure homogenization and ultra-high-pressure homogenization, yeast and lactic acid bacteria step-by-step fermentation. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0025] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0026] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0027] In the present invention, unless otherwise specified, the preparation of the sucrose solution used in the examples of the present invention comprises the following steps: dissolving sucrose in water to obtain a sucrose solution with a concentration of 1 g / mL.

[0028] In the present invention, unless otherwise specified, the preparation of the osmanthus extract used in the embodiments of the present invention comprises the following steps: grinding osmanthus into powder, adding 5 times the mass of 95% ethanol thereto and ultrasonically extracting for 10 minutes, concentrating the obtained extract under reduced pressure, removing the solvent, adding 0.5% (w / v) lemon juice thereto, sterilizing at 75°C for 10 minutes, and obtaining an osmanthus extract.

[0029] In the present invention, unless otherwise specified, the deposit number of the Saccharomyces cerevisiae used in the examples of the present invention is CGMCC No.29794.

[0030] In the present invention, unless otherwise specified, the deposit number of Lactobacillus plantarum used in the examples of the present invention is CGMCC NO: 29644.

[0031] In the present invention, unless otherwise specified, the deposit number of the Acetobacter used in the comparative examples of the present invention is CGMCC No.16448.

[0032] Example 1

[0033] The osmanthus black tea and the preparation method thereof of the present embodiment specifically comprise the following steps:

[0034] S1. Add 5 times the mass of water to the black tea, homogenize at 150 MPa for 20 min using a homogenizer, filter using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize at 450 MPa for 10 min to obtain a black tea solution;

[0035] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.7:0.4; the volume fraction of the brewer's yeast seed liquid is 2%;

[0036] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours, and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 2.5%.

[0037] Example 2

[0038] The osmanthus black tea and the preparation method thereof of the present embodiment specifically comprise the following steps:

[0039] S1. Add 5 times the mass of water to the black tea, homogenize it at 100 MPa for 30 min using a homogenizer, filter it using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize it at 400 MPa for 15 min to obtain a black tea solution;

[0040] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.6:0.5; the volume fraction of the brewer's yeast seed liquid is 1.5%;

[0041] S3, add 10 7CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 3%.

[0042] Example 3

[0043] The osmanthus black tea and the preparation method thereof of the present embodiment specifically comprise the following steps:

[0044] S1. Add 5 times the mass of water to the black tea, homogenize it at 200 MPa for 10 min using a homogenizer, filter it using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize it at 500 MPa for 5 min to obtain a black tea solution;

[0045] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.8:0.3; the volume fraction of the brewer's yeast seed liquid is 2.5%;

[0046] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours, and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 2%.

[0047] Example 4

[0048] The osmanthus black tea and the preparation method thereof of the present embodiment specifically comprise the following steps:

[0049] S1. Add 5 times the mass of water to the black tea, homogenize it at 100 MPa for 30 min using a homogenizer, filter it using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize it at 500 MPa for 5 min to obtain a black tea solution;

[0050] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.6:0.3; the volume fraction of the brewer's yeast seed liquid is 1.5%;

[0051] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours, and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 2%.

[0052] Example 5

[0053] The osmanthus black tea and the preparation method thereof of the present embodiment specifically comprise the following steps:

[0054] S1. Add 5 times the mass of water to the black tea, homogenize it at 200 MPa for 10 min using a homogenizer, filter it using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize it at 400 MPa for 15 min to obtain a black tea solution;

[0055] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.8:0.3; the volume fraction of the brewer's yeast seed liquid is 2.5%;

[0056] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 3%.

[0057] Comparative Example 1

[0058] The method is basically the same as Example 1, except that the second homogenization conditions are the same as the first homogenization conditions, and specifically include the following steps:

[0059] S1. Add 5 times the mass of water to the black tea, homogenize it at 150 MPa for 20 min using a homogenizer, filter it using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize it at 150 MPa for 20 min to obtain a black tea solution;

[0060] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.7:0.4; the volume fraction of the brewer's yeast seed liquid is 2%;

[0061] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours, and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 2.5%.

[0062] Comparative Example 2

[0063] The method is basically the same as Example 1, except that the saccharomyces cerevisiae seed solution and the lactobacillus plantarum seed solution are added simultaneously, and specifically comprises the following steps:

[0064] S1. Add 5 times the mass of water to the black tea, homogenize at 150 MPa for 20 min using a homogenizer, filter using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize at 450 MPa for 10 min to obtain a black tea solution;

[0065] S2, add sucrose solution, osmanthus extract, concentration of 10 7 CFU / mL of Saccharomyces cerevisiae seed solution and a concentration of 10 7 CFU / mL of plant lactobacillus seed liquid is fermented at 30°C for 68 hours and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume ratio of black tea solution, sucrose solution and osmanthus extract is 1:0.7:0.4; the volume fraction of brewer's yeast seed liquid is 2%; and the volume fraction of Lactobacillus plantarum seed liquid is 2.5%.

[0066] Comparative Example 3

[0067] The method is basically the same as Example 1, except that the Lactobacillus plantarum seed liquid is replaced with Acetobacter aceticus seed liquid, and specifically comprises the following steps:

[0068] S1. Add 5 times the mass of water to the black tea, homogenize at 150 MPa for 20 min using a homogenizer, filter using a microfiltration membrane, concentrate the permeate at level 1, and then homogenize at 450 MPa for 10 min to obtain a black tea solution;

[0069] S2, add sucrose solution, osmanthus extract and 10% 7 CFU / mL of brewer's yeast seed liquid, fermented at 30°C for 68h to obtain a composite fermentation liquid; wherein the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:0.7:0.4; the volume fraction of the brewer's yeast seed liquid is 2%;

[0070] S3, add 10 7 CFU / mL of Lactobacillus plantarum seed liquid is fermented at 30°C for 68 hours, and then sterilized at 85°C for 25 minutes to obtain osmanthus black tea; wherein the volume fraction of the Lactobacillus plantarum seed liquid is 2.5%.

[0071] Test Example 1

[0072] Based on Examples 1-5 and Comparative Examples 1-3, the solubility and other properties of the nutrients in the osmanthus black tea were tested:

[0073] Solubility determination: add 1.5 g of target nutrient to 75 mL of distilled water and 0.2% NaOH solution respectively, stir magnetically for 30 min, centrifuge at 4800 r / min for 15 min, aspirate the supernatant, measure the absorbance at A650 using the Folin phenol method, and calculate the nutrient content using the standard curve.

[0074] Foaming stability determination: Use 0.05 mol / L KH2PO4-NaOH (pH 7.0) buffer to prepare a 1% concentration, take 50 mL and stir at 10000 r / min for 2 min, record the foaming volume (V0) and solution volume; record the foam volume (Vt) after standing for 30 min; calculate the foaming property (FAI = (V0-50) / 50) and foaming stability (FS = (V0-Vt) / V0) according to the formula.

[0075] Table 1

[0076]

[0077]

[0078] It can be seen from Table 1 that the method of the embodiment can effectively change the physical and chemical properties of nutrients, so that the polarity and solubility of the nutrients are increased, and the utilization rate of the nutrients is greatly improved.

[0079] Test Example 2

[0080] 20 sensory evaluators (20 males and 20 females) were selected for training. In order to ensure that the sensory evaluators gradually mastered the correct method of sensory analysis, the sensory evaluators should have basic knowledge of sensory analysis procedures and the ability to perceive, identify and describe sensory stimuli. The sensory evaluation standards are shown in Table 2, and the sensory evaluation results are shown in Table 3:

[0081] Table 2 Sensory evaluation table

[0082]

[0083] Table 3 Sensory evaluation results

[0084]

[0085]

[0086] It can be seen from Table 3 that the appropriate strains and processes make the osmanthus black tea have a harmonious taste, rich characteristic aroma, bright and pure color, and clear and transparent liquid.

[0087] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing osmanthus black tea, characterized in that: The specific steps include: S1, homogenizing, separating, concentrating, and homogenizing twice the black tea to obtain a black tea solution; S2, adding sucrose solution, osmanthus extract and yeast seed solution to the black tea solution described in S1, and fermenting to obtain a composite fermentation liquid; S3, adding lactic acid bacteria seed liquid to the composite fermentation liquid described in S2, and obtaining the osmanthus black tea through fermentation and sterilization.

2. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S1, the primary homogenization is carried out at 100Mpa-200Mpa for 10min-30min.

3. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S1, the concentration level is 1-3.

4. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S1, the secondary homogenization is carried out at 400Mpa-500Mpa for 5min-15min.

5. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S2, the volume ratio of the black tea solution, the sucrose solution and the osmanthus extract is 1:(0.6-0.8):(0.3-0.5).

6. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S2, the yeast is Saccharomyces cerevisiae; the concentration of the yeast seed solution is 10 6 -10 8 CFU / mL; the volume fraction of the yeast seed liquid is 1.5%-2.5%.

7. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S3, the lactic acid bacteria is Lactobacillus plantarum; the concentration of the lactic acid bacteria seed solution is 10 6 -10 8 CFU / mL; the volume fraction of the lactic acid bacteria seed liquid is 2%-3%.

8. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S3, the sterilization is performed at 80°C-90°C for 20min-30min.

9. The method for preparing osmanthus black tea according to claim 1, characterized in that: In S2 and S3, the fermentation was independently carried out at 29°C-31°C for 24h-72h.

10. Osmanthus black tea prepared by the method according to any one of claims 1 to 9.

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