Cream-shaped Sanjing mountain black tea with stomach tonifying and kidney tonifying functions and preparation method of cream-shaped Sanjing mountain black tea

Abstract

The invention discloses a cream-shaped Sanjing mountain black tea with stomach-tonifying and kidney-tonifying functions and a preparation method of the cream-shaped Sanjing mountain black tea. The preparation method comprises the following steps: obtaining dendrobium officinale superfine powder by using a vacuum low-temperature superfine grinding technology, then sequentially performing withering, fixation and fermentation on fresh Fuding white tea leaves, uniformly mixing fermented black tea and the dendrobium officinale superfine powder according to a mass ratio of 500 (145 after drying): 70, and gently and softly twisting for 5 minutes to enable the dendrobium officinale superfine powder to be adsorbed on the surface of the fermented black tea, and drying the softly twisted tea leaves at the temperature of 85 DEG C for 90 minutes, putting the dried tea leaves at normal temperature, and sieving the dried tea leaves with a 200-mesh pharmacopoeia sieve to remove fine powder so as to obtain the cream-like fermented black tea. The highest comprehensive score of sensory evaluation of the cream-shaped Sanjing mountain black tea is 91.25, the adsorption rate of the dendrobium officinale superfine powder is 31.76 + / -0.46%, and the polysaccharide content is 96.04 + / -1.78 mg / g; and boiling water is added according to a tea-water ratio of 1: 50 (g / mL) for soaking for 4 times, and the polysaccharide extraction rate of water reaches (95.23 + / -2.55)%. The cream-shaped Sanjing mountain black tea is endowed with the effects of tonifying the stomach, promoting the secretion of saliva or body fluid, enriching yin and nourishing the kidney, and the technical problem that the dendrobium officinale powder is dissolved in water, agglomerated and hung on the wall is solved.

Description

Technical Field

[0001] The present invention relates to a Fanjing Mountain tea, in particular to a cream-shaped Fanjing Mountain black tea with the functions of benefiting the stomach and tonifying the kidney and a preparation method thereof, belonging to the technical field of tea preparation. Background Art

[0002] Plant functional tea drinks are highly praised and loved by modern people for their natural, green and health-care advantages. Dendrobium officinale is both a food and a traditional Chinese medicine, which brings a broader development space and market prospect for the Dendrobium officinale industry.

[0003] Dendrobium powder is a powdery substance obtained by dehydrating and pulverizing fresh Dendrobium officinale stems. It is favored by consumers for its freshness, convenience and easy absorption. When Dendrobium officinale powder is pulverized, it is easy to oxidize when contacting with air; its particle size is relatively large, and it is not easily absorbed by the stomach and intestines when taken directly, wasting resources; Dendrobium officinale powder has a high chlorophyll content and has a strong grassy taste, with poor taste; Dendrobium officinale powder has a high polysaccharide content and is not easily dispersed in water, and is easy to form lumps and adhere to the wall when dissolved in water, and it adheres to the inner wall of the mouth when taken; Dendrobium officinale powder has a sweet and slightly cold nature, is greasy and sticky, and those with weak spleen and stomach and phlegm-dampness are not suitable for long-term taking, which brings certain troubles to consumers.

[0004] "Fanjing Mountain tea" has been recognized as a regional public brand of tea in Tongren City and is sold well at home and abroad. According to the test results, the Fuding Dabaicha variety in Fanjing Mountain is rich in tea polyphenols, caffeine and free amino acids, with contents of (18.85 ± 1.91)%, (3.23 ± 0.72)% and (4.27 ± 0.47)% respectively. The sensory evaluation of the curly-shaped black tea in Fanjing Mountain processed from the Fuding Dabaicha variety is better, and it has more promotional significance and value. However, the function of clearing heat and relieving summer heat of tea drinks can no longer meet the higher-level needs of consumers for health preservation.

[0005] The present invention utilizes the adsorption effect of fermented Fuding Dabaicha in Fanjing Mountain on ultrafine powder of Dendrobium officinale to prepare a plant functional tea drink with the functions of benefiting the stomach and tonifying the kidney. The cream-shaped Fanjing Mountain black tea in the present invention improves the quality of black tea, expands the sales channels of Dendrobium officinale, and effectively meets the higher-level needs of consumers for tea drinks with health preservation effects. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a cream-like Fanjingshan black tea with the functions of benefiting the stomach and tonifying the kidney and its preparation method in view of the deficiencies in the prior art. In the cream-like Fanjingshan black tea of the present invention, Dendrobium officinale endows the black tea with the special effects of promoting fluid production to benefit the stomach, nourishing yin and tonifying the kidney, and a unique Dendrobium fragrance; the co-growing black tea of Dendrobium makes the ultrafine powder of Dendrobium easily soluble in water, with strong dispersibility, not forming clusters, not sticking to the wall, and being easily absorbed, endowing the aqueous solution of Dendrobium with a unique tea fragrance and enhancing the taste of the aqueous solution of Dendrobium; the black tea helps to control the slightly cold nature of Dendrobium officinale, preventing it from damaging the spleen and stomach and expanding the consumer group. The cream-like Fanjingshan black tea in the present invention has the special effects of promoting fluid production to benefit the stomach and nourishing yin and tonifying the kidney, solving the technical problems of poor taste of Dendrobium officinale powder, forming clusters and sticking to the wall when dissolved in water, difficult absorption, and a small consumer group. At the same time, the quality of the black tea is improved.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a preparation method of a cream-like Fanjingshan black tea (Fanjingshan "cream" black tea) with the functions of benefiting the stomach and tonifying the kidney, including the following steps: (1) Preparation of ultrafine powder of Dendrobium officinale: Wash the fresh stems of Fanjingshan Dendrobium officinale, cut them into oblique slices, place the oblique slices in a drying oven to dry, and then use low-temperature ultrafine grinding technology to crush and break the dried oblique slices, and sieve to obtain the ultrafine powder of Dendrobium officinale, which is sealed and stored at room temperature for later use; (2) Preparation of fermented black tea: Wilt the fresh leaves of Fuding Dabaicha with one bud and two leaves that have been purified at room temperature indoors. The wilted tea leaves are repeatedly kneaded and killed by a kneading machine, and the killed tea leaves are fermented at room temperature indoors to obtain fermented black tea; (3) Preparation of cream-like Fanjingshan black tea: Evenly sprinkle the ultrafine powder of Dendrobium officinale obtained in step (1) into the fermented black tea obtained in step (2). The mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is 500:40 - 100. Gently knead by hand to make the ultrafine powder of Dendrobium evenly mixed and adhered to the surface of the fermented black tea, and then dry to make the ultrafine powder and the fermented black tea more tightly adsorbed. After cooling to room temperature, pass through a pharmacopoeia sieve, and gently sieve to remove the ultrafine powder of Dendrobium that is not adhered to the fermented black tea, obtaining tea leaves with yellowish-white Dendrobium particles evenly adhered to the surface, which is the cream-like Fanjingshan black tea. The present invention names it Fanjingshan "cream" black tea.

[0008] In the above technical solution, the Fanjingshan Dendrobium officinale described in step (1) is selected from Fanjingshan Dendrobium officinale cultivated in the tea area of Songtao Miao Autonomous County, Fanjingshan; the oblique slices are 1 - 2 cm long and 2 - 3 mm thick, and the oblique slices are dried in a drying oven at 50 °C until the moisture content is below 5%.

[0009] In the above technical solution, in step (1), the dried obliquely sliced pieces are crushed and broken by using cryogenic ultrafine pulverization technology. When crushing and breaking, the temperature is -13 ± 1 °C, the powder discharge temperature is -13 ± 1 °C, the particle size of the discharged powder is 10 - 25 μm, and after passing through a 200-mesh pharmacopoeia sieve, ultrafine powder of Dendrobium officinale is obtained.

[0010] In the above technical solution, in step (2), the Fuding Dabaicha tea is selected from the Fuding Dabaicha tea cultivated in the tea-growing area of Songtao Miao Autonomous County, Fanjingshan, and is fermented with reference to the processing technical regulations of "Fanjingshan Black Tea" (DB52 / T 1012—2015): withering at room temperature in a room with a relative humidity of 55 - 60% for 17 h, the withered tea leaves are repeatedly kneaded and de-enzymed for 2 h with a kneading machine, and the de-enzymed tea leaves are fermented at room temperature in a room with a relative humidity of 55 - 60% for 4 h to obtain fermented black tea.

[0011] In the above technical solution, in step (2), after the de-enzymed tea leaves are fermented, a certain mass of fermented black tea is weighed, and after being kneaded gently, dried, cooled, and sieved, the dried fermented black tea is weighed again, and the water loss of the dried fermented black tea is calculated, so as to obtain the humidity of the fermented black tea. The humidity of the fermented black tea is (71.27 ± 0.64%) and meets the requirements.

[0012] In the above technical solution, in step (3), the mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is preferably 500:50 - 90, and further preferably 500 (about 145 after drying):70.

[0013] In the above technical solution, in step (3), after evenly sprinkling the ultrafine powder of Dendrobium officinale on the fermented black tea, gently knead it by hand for 5 min to make the ultrafine powder of Dendrobium officinale evenly mixed and adhere to the surface of the fermented black tea, then bake it at a temperature of 85 °C for 90 min to make the ultrafine powder of Dendrobium officinale and the fermented black tea adsorb more closely. After cooling to room temperature, sieve it gently with a 200-mesh pharmacopoeia sieve to remove the ultrafine powder of Dendrobium that has not adhered to the tea leaves, and obtain tea leaves with yellowish-white Dendrobium particles evenly adhered to the surface, that is, frost-like Fanjingshan black tea, which is named Fanjingshan "Frost" black tea in the present invention.

[0014] The present invention also provides a kind of frost-like Fanjingshan black tea (Fanjingshan "Frost" black tea), which is obtained by the above preparation method. The daily dosage of the frost-like Fanjingshan black tea is preferably 18 - 38 g.

[0015] Compared with the prior art, it has the following characteristics: (1) In the present invention, the Dendrobium - associated black tea makes the ultrafine powder of Dendrobium officinale easily soluble in water, has strong dispersibility, does not form lumps, does not adhere to the wall, and is easily absorbed, solving the technical problems of poor taste of the ultrafine powder of Dendrobium officinale, forming lumps and adhering to the wall when dissolved in water, difficult absorption, and a small consumer group.

[0016] (2)The Fanjing "Frost" black tea in the present invention belongs to a plant functional tea drink. Dendrobium officinale endows the black tea with the effects of promoting fluid production to benefit the stomach, nourishing yin and tonifying the kidney, clearing the liver and improving eyesight, etc., and a unique Dendrobium fragrance. Due to its effect of protecting the stomach and liver, it is more popular among alcohol drinkers. Black tea is warm in nature and has the effects of warming the stomach and dispelling cold, promoting fluid production to relieve summer heat, diuresis, etc. The combination of Dendrobium and black tea endows the aqueous solution of Dendrobium with a unique tea fragrance and enhances the taste of the Dendrobium water. It also neutralizes the slightly cold nature of Dendrobium officinale, preventing it from damaging the spleen and stomach, and is suitable for people with weak spleen and stomach, thus expanding the consumer group. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 To screen the adsorption rate (g / g) of the frost-like Fanjing Mountain black tea (named Fanjing "Frost" black tea in the present invention) in the examples to the ultrafine powder of Dendrobium officinale. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes in detail the specific implementation manners of the technical solutions of the present invention, but the present invention is not limited to the following description: Screening example: Screening the optimal mass ratio of fermented black tea and the ultrafine powder of Dendrobium officinale

[0019] (1)Preparing the ultrafine powder of Dendrobium officinale: Select Dendrobium officinale cultivated in the tea area of Songtao Miao Autonomous County, Fanjing Mountain as the material. Wash 2.5 kg of fresh Dendrobium officinale stems, cut them into oblique slices with a length of 1 - 2 cm and a thickness of 2 - 3 mm, and dry the oblique slices in a drying oven at 50°C until the moisture content is below 5%. Then use low-temperature ultrafine grinding technology to crush and break the dried oblique slices. The temperature during crushing and breaking is -13 ± 1°C, the powder discharge temperature is -13 ± 1°C, and the particle size of the discharged powder is 10 - 25 μm. Pass through a 200-mesh pharmacopoeia sieve to obtain the ultrafine powder of Dendrobium officinale, and store it sealed at room temperature for later use.

[0020] There are various methods of processing and using Dendrobium in past dynasties. "Complete Collection of Medical Records in the General Compendium of Ancient and Modern Books" Volume 188 states: "Boiling, powdering, or soaking in wine to take Dendrobium are all good." "Commentary on Medical Herbs from the Past" states: "When using it in decoctions, soak it in wine, dry it in the sun, use it in pills, cut it thinly, soak it in rice drink, and dry it and grind it." Sun Simiao, the king of medicine in the Tang Dynasty, recorded in "Emergency Prescriptions Worth a Thousand Gold" the method of using Dendrobium in pills and powders: "When using Dendrobium in pills and powders, first beat it extremely finely with an anvil and hammer, and then put it into a mortar. Otherwise, it will not be pounded thoroughly, and the same is true when soaking it in wine." It can be seen that "using it in pills and powders" is an effective method of consumption that appeared earlier.

[0021] Low-temperature full-automatic ultrafine grinding makes use of the functions of the machine vibrating up and down, the grinding rod grinding regularly, shearing, etc., so as to achieve the purpose of finely grinding and breaking the cell wall of materials. A low-temperature refrigerator is equipped to lower the temperature of the machine, ensuring the freshness and activity of the materials after grinding. The ultrafine grinding and cell wall breaking technology can grind materials to the micron level or even the nanometer level, with a cell wall breaking rate > 98%. The particle size of the product is generally 10 - 25 μm. It has the advantages of small loss of functional components, high utilization rate, promotion of the dissolution of active ingredients and the absorption of nutrients, improvement of taste, easy storage, easy transportation, and convenient use, and is widely used and extremely favored by consumers.

[0022] The ultrafine powder of Dendrobium officinale is processed from the stems of Dendrobium officinale after drying and sterilization using ultrafine grinding technology. Because it is ground in a low-temperature and closed state, basically no effective components such as the nutritional components and active substances of Dendrobium officinale are lost during the process of breaking the cell wall. After the cell wall is broken, it is more conducive to human absorption and improves the utilization rate.

[0023] (2) Preparation of fermented black tea: Select Fuding Dabaicha cultivated in the tea-growing area of Songtao Miao Autonomous County, Fanjingshan as the material, and carry out fermentation with reference to the processing technical regulations of "Fanjingshan Black Tea" (DB52 / T1012—2015): The fresh leaves of Fuding Dabaicha with one bud and two leaves after purification are withered at room temperature with a relative humidity of 55 - 60% for 17 h. The withered tea leaves are repeatedly kneaded and fixed with a kneading machine for 2 h. The tea leaves after fixation are fermented at room temperature with a relative humidity of 55 - 60% for 4 h to obtain fermented black tea. Weigh a certain mass of the fermented black tea, gently knead it by hand for 5 min, dry the kneaded tea leaves at 85°C for 90 min, cool to room temperature, and then pass through a 200-mesh pharmacopoeia sieve. Gently sieve to remove fine powder to obtain dried fermented black tea (that is, the fermented black tea after drying), weigh it again, calculate the water loss of the fermented black tea, and obtain the humidity of the fermented black tea. The humidity of the fermented black tea is (71.27 ± 0.64)%, meeting the requirements.

[0024] (3) Preparation of frost-like Fanjingshan black tea: The ultrafine Dendrobium officinale powder obtained in step (1) is evenly sprinkled into the fermented black tea obtained in step (2). The mass ratio of the fermented black tea to the ultrafine Dendrobium officinale powder is 500:40, 500:50, 500:60, 500:70, 500:80, 500:90, and 500:100, respectively. The ultrafine Dendrobium officinale powder or ordinary Dendrobium powder is not easy to disperse in water or hot water due to its high polysaccharide content, and is easy to form a mass and stick to the wall. Most of the cells of the rolled and withered Fanjingshan Fuding Dabaicha are broken, and the colloid substances in the cells are attached to the surface of the tea leaves. The colloid substances on the surface of the fermented tea leaves are more viscous. The ultrafine Dendrobium officinale powder is evenly sprinkled on the surface of the fermented tea leaves, and gently twisted by hand for 5 minutes to make the ultrafine Dendrobium officinale powder evenly mixed and adhered to the surface of the fermented black tea, and then baked at 85°C for 90 minutes. min, so that the superfine powder and fermented black tea are more closely adsorbed, and after cooling to room temperature, the superfine powder of Dendrobium officinale that is not attached to the tea leaves is lightly sieved with a 200-mesh pharmacopoeia sieve to remove the superfine powder of Dendrobium officinale that is not attached to the tea leaves, and the tea leaves with yellow-white dendrobium officinale particles evenly attached to the surface are obtained, that is, the frosty Fanjing Mountain black tea, which is named Fanjing "Frost" black tea in the present invention. During the rolling and drying process, the colloid substance in the broken wall of the superfine powder of Dendrobium officinale may be dissolved and adsorbed on the surface of the black tea, which reduces the adhesion between the superfine powder of Dendrobium officinale. The black tea with the superfine powder of Dendrobium officinale attached to the surface and the superfine powder of Dendrobium officinale are soaked in hot water. The results show that the superfine powder of Dendrobium officinale in Fanjing "Frost" black tea is evenly dispersed at the bottom of the cup in hot water, in the form of particles, without agglomeration or wall hanging, while the superfine powder of Dendrobium officinale is unevenly dispersed in hot water, agglomerates, and the dendrobium agglomerates sink to the bottom or suspend or hang on the wall.

[0025] The following investigations were conducted on the frosty Fanjing Mountain black tea obtained by the present invention (named Fanjing "Frost" black tea by the present invention): 1. Investigate the adsorption rate of frosty Fanjingshan black tea Dendrobium candidum ultrafine powder: The unadsorbed ultrafine powder was collected and weighed, and the adsorption rate (Y) of the frosty Fanjingshan black tea (Fanjing "Frost" black tea) on the ultrafine powder of Dendrobium candidum was calculated according to the following formula: Y = (m 1 -m 2 ) / (M+m 1 -m 2 )×100%, where: Y is the adsorption rate of frosty Fanjingshan black tea (Fanjing “Frost” black tea) on ultrafine powder of Dendrobium candidum (%), m 1 is the mass of superfine powder of Dendrobium candidum added (g), m 2 is the mass of unadsorbed ultrafine powder of Dendrobium officinale (g), and M is the mass of the added fermented black tea after dryness (g).

[0026] Different mass ratios of superfine powder of Dendrobium officinale were added to fermented black tea. The adsorption rate of superfine powder of Dendrobium officinale on frosty Fanjingshan black tea (Fanjing "Frost" black tea) was as follows: Figure 1 As shown by Figure 1It can be seen that different masses of ultrafine powder of Dendrobium officinale are uniformly mixed into a certain mass of fermented black tea. As the mass of the ultrafine powder of Dendrobium officinale increases, the adsorption rate of Fanjing "Frost" black tea to the ultrafine powder of Dendrobium officinale continuously increases, from 21% to 39.43%. When the mass ratio of fermented tea leaves to the ultrafine powder of Dendrobium is between 500:40 - 500:100, the increase in the adsorption rate decreases from 3.75% to 2.42%. When the mass ratio of fermented black tea to the ultrafine powder of Dendrobium officinale is between 500:90 - 500:100, the increase in the adsorption rate significantly decreases.

[0027] 2. Examine the sensory evaluation of Fanjing Mountain black tea in frost form: The sensory evaluation method of Fanjing Mountain black tea in frost form (Fanjing "Frost" black tea) follows the standard of "Tea Sensory Evaluation Method" (GB / T 23776 - 2018). The five-factor tea evaluation method of appearance, aroma, taste, soup color and leaf bottom is adopted. Five tea evaluation personnel from the national-level Hou Yanshuang Tea Skill Master Studio conduct sensory evaluation on Fanjing "Frost" black tea, and conduct weighted scoring according to the percentage system: 25% for appearance, 10% for soup color, 25% for aroma, 30% for taste, and 10% for leaf bottom.

[0028] Place the tea leaves of different series of Fanjing Mountain black tea in frost form (Fanjing "Frost" black tea) on the evaluation plate, conduct encryption treatment, and conduct appearance evaluation; use a tray balance to weigh 3g of tea leaves of different series of Fanjing Mountain black tea in frost form (Fanjing "Frost" black tea) respectively, inject boiling water according to the tea-water ratio of 1:50 (m / v), cover and soak for 5 minutes. After the soaking ends, immediately conduct evaluation on the inner quality of the tea soup.

[0029] The Fanjing Mountain black tea in frost form (Fanjing "Frost" black tea) with the ratio of fermented tea leaves to the ultrafine powder of Dendrobium officinale being 500:40, 500:50, 500:60, 500:70, 500:80, 500:90, 500:100, 500:0) are respectively named FJT4, FJT5, FJT6, FJT7, FJT8, FJT9, FJT10 and FJT0. The sensory evaluation comments are as follows: Appearance, relatively tight and clean, with a dark brown and golden color, covered with flat strips, relatively uniform; Soup color, light yellow and brighter, orange-yellow and bright, light yellow and bright; Aroma, showing sweet potato aroma, showing tea flavor; Taste, sweet with the taste of Dendrobium officinale and smooth; Leaf bottom, the leaf stalks are separated and sticky, with a dark brown color. The sensory evaluation scores are as follows: Table 1 Sensory evaluation scores of Fanjing Mountain black tea in frost form (Fanjing "Frost" black tea) with different ratios

[0030] The adsorption rate of Fanjing Frost black tea on superfine Dendrobium officinale powder and the five-factor sensory indicators of tea evaluation, including appearance, soup color, aroma, taste and leaf bottom, were comprehensively investigated. Fanjing "Shuang" black tea was prepared by fermenting Fuding Dabai tea and superfine Dendrobium officinale powder in a mass ratio of 500 (about 145 after dry weight):70. The adsorption rate of Fanjing "Shuang" black tea on superfine Dendrobium officinale powder was (31.76 ± 0.46)%, and the comprehensive score of sensory evaluation was the highest, 91.25.

[0031] 3. Investigation of the Dendrobium officinale polysaccharide content in Frosted Fanjingshan Black Tea (Fanjing “Frost” Black Tea) The Chinese Pharmacopoeia (2020 edition) defines polysaccharides as the hallmark indicator of the active ingredients of Dendrobium officinale. The determination of Dendrobium officinale polysaccharides in Fanjing "Shuang" black tea refers to the method in the Chinese Pharmacopoeia (2020 edition) and the method reported by Tan Shancai et al. for the optimization of the hydrolysis process of Dendrobium officinale polysaccharides and the determination of mannose content.

[0032] 3.1. Drawing of the standard curve of glucose reference substance Dry the glucose reference substance to constant weight, weigh accurately, and add water to make a solution containing 95 μg per 1 ml to obtain the polysaccharide reference solution.

[0033] Accurately measure 0.2 ml, 0.4 ml, 0.6 ml, 0.8 ml, and 1.0 ml of the reference solution and place them in 10 ml stoppered test tubes respectively. Take another stoppered test tube and add 1.0 ml of water as a blank. Add water to each to make up to 1.0 ml, accurately add 1 ml of 5% phenol solution (prepared and used immediately), shake well, then accurately add 5 ml of sulfuric acid, shake well, heat in a boiling water bath for 20 min, take out, cool in an ice bath for 5 min, and use UV-visible spectrophotometry to measure the absorbance of the solution in each stoppered test tube at a wavelength of 488 nm. Use absorbance as the ordinate and concentration as the abscissa to draw a standard curve, and get: A=0.0558C+0.1397(R 2 =0.9995), where A is absorbance; C is the concentration of polysaccharide solution, μg / mL.

[0034] 3.2 Determination of Dendrobium officinale polysaccharides in frosted Fanjingshan black tea Refer to the phenol-sulfuric acid method for determining the polysaccharide content of Dendrobium officinale: Weigh three portions of 1.0 g of frosted Fanjing Mountain black tea (FJT7) precisely. Calculate according to the adsorption rate of dry tea after fermentation tea is dried to the ultrafine powder of Dendrobium officinale, and weigh three portions of 0.3176 g of the ultrafine powder of Dendrobium officinale dried at 85 °C for 90 min precisely. Place the six samples in 150 mL conical flasks respectively, add 200 mL of water to each conical flask respectively, reflux and extract at 70 °C for 2 h respectively, filter, and make the volume of the filtrate up to 250 mL with water. Precisely measure 2 mL of the extract respectively, place it in a 15 ml centrifuge tube, add 10 ml of absolute ethanol precisely, shake well, refrigerate for 2 hours, take it out, centrifuge (at a speed of 4000 revolutions per minute) for 20 min, discard the supernatant, wash the precipitate with absolute ethanol twice, centrifuge, discard the supernatant, dissolve the precipitate in hot water, transfer it to a 25 ml volumetric flask, let it cool, add water to the scale, shake well, and wait for measurement.

[0035] Precisely measure 1 ml of each of the sample solution and the blank control solution, place it in a 10 ml stoppered test tube, according to the method under the preparation of the standard curve, and add 1 ml of 5% phenol solution precisely as in "3.1. Preparation of the standard curve of glucose reference substance". Measure the absorbance according to the law. According to the standard curve A = 0.0558C + 0.1397 (R 2 = 0.9995), calculate the content of polysaccharide of Dendrobium officinale in the frosted Fanjing Mountain black tea, as shown in Table 2: Table 2 Content of polysaccharide of Dendrobium officinale in frosted Fanjing Mountain black tea (Fanjing "Frost" black tea) / (mg / g)

[0036] 4. Investigate the usage and dosage of frosted Fanjing Mountain black tea (Fanjing "Frost" black tea): Precisely weigh three portions of 2.0 g of Fanjing "Frost" black tea (FJT7), place them in 500 mL stoppered conical flasks respectively, add 400 mL of water, reflux and extract at 70 °C for 60 min, filter, and make the volume up to 500 mL. Determine the polysaccharide content in Fanjing "Frost" black tea according to the methods in 3.1 and 3.2. Precisely weigh three portions of 2.0 g of Fanjing "Frost" black tea (FJT7), place them in 150 mL stoppered conical flasks respectively, add 100 mL of boiling water according to the tea-water ratio of 1:50 (m / v), soak for 5 times, 5 min each time. For the filtrate collected each time and the ultrafine powder of Dendrobium officinale dispersed in the filtrate, determine the polysaccharide content according to the methods in 3.1 and 3.2. Calculate the polysaccharide extraction rate for each soaking. The results are shown in Table 3: Table 3 Influence of soaking times on the polysaccharide extraction rate in Fanjing "Frost" black tea / %

[0037] Table 3 results show that according to the national standard GB / T 23776-2018 Tea Sensory Evaluation Method, when boiling water is used to soak Fanjing "Frost" black tea 5 times, the polysaccharide extraction rate can reach (96.36 ± 3.78)%. When soaked for the 4th time, the polysaccharide extraction rate in Fanjing "Frost" black tea has reached (95.23 ± 2.55)%. Considering from the perspective of polysaccharide extraction rate, it is recommended that when soaking Fanjing "Frost" black tea, add boiling water according to the tea-water ratio of 1:50 (m / v), cover the bottle cap and soak 4 times, 5 minutes each time.

[0038] Pharmacopoeia of the People's Republic of China (2020 Edition) recommends 6 - 12 g of dried Dendrobium officinale. According to the adsorption rate of 31.76% of Dendrobium officinale ultrafine powder in Fanjing "Frost" black tea (FJT7), it is recommended that the daily dosage of Fanjing "Frost" black tea be 18 - 38 g.

[0039] Dendrobium officinale is a traditional precious Chinese medicinal material. Shennong Ben Cao Jing listed Dendrobium officinale as a top-grade medicinal material. Tao Zang, a Taoist medical classic in the Tang Dynasty, listed Dendrobium officinale as the first of the nine great fairy herbs. Li Shizhen, a medical scientist in the Ming Dynasty, recorded in Compendium of Materia Medica: "Dendrobium can dispel rheumatism and relieve qi, tonify the deficiencies of the five zang-organs, build up the body and benefit essence. Taking it for a long time can thicken the intestines and stomach, supplement internal deficiencies, lighten the body and prolong life, replenish qi and remove heat, treat weakness of the waist and knees in men, strengthen yang, tonify the kidney and boost strength, strengthen bones and muscles, and treat fever and spontaneous sweating." Pharmacopoeia of the People's Republic of China (2020 Edition) records that Dendrobium officinale tastes sweet and slightly cold, and belongs to the stomach and kidney meridians; it has the effects of promoting the production of body fluid to quench thirst, nourishing yin and clearing heat; it is used for consumptive fever with dry mouth and thirst, deficiency of stomach yin, anorexia and retching, lingering low-grade fever after illness, yin deficiency and internal heat, hectic fever due to yin deficiency, blurred vision, and flaccid bones and muscles. Modern pharmacology shows that Dendrobium officinale polysaccharide has significant curative effects in aspects such as anti-tumor, immune regulation, antioxidant, protecting the liver and improving eyesight, lowering blood sugar, blood pressure, blood lipid, uric acid, and clearing the throat and protecting the voice.

[0040] Fanjing "Frost" black tea belongs to plant functional tea drinks. Dendrobium officinale endows black tea with special effects such as promoting the production of body fluid to quench thirst, nourishing yin and tonifying the kidney, and clearing the liver and improving eyesight, as well as a unique Dendrobium fragrance. Because of its effect of protecting the stomach and liver, it is more popular among alcohol drinkers; black tea is warm in nature and has the effects of warming the stomach and dispelling cold, promoting the production of body fluid to relieve summer heat, and diuresis. The combination of Dendrobium and black tea endows the Dendrobium aqueous solution with a unique tea fragrance and enhances the taste of the Dendrobium water; it also neutralizes the slightly cold nature of Dendrobium officinale to prevent it from damaging the spleen and stomach, and is suitable for people with spleen and stomach deficiency-cold, expanding the consumer group.

[0041] From the screening examples, it can be seen that when preparing Fanjing "Frost" black tea with fermented Fuding Dabaicha and Dendrobium officinale ultrafine powder at a mass ratio of 500 (about 145 after drying):60 - 70, the adsorption rate of Fanjing "Frost" black tea to Dendrobium officinale ultrafine powder is relatively high, and the comprehensive score of sensory evaluation is also relatively high. Considering comprehensively from the adsorption rate and sensory evaluation, the following formal example is carried out at a mass ratio of 500 (about 145 after drying):70. Example 1:

[0042] (1) Preparation of ultrafine powder of Dendrobium officinale: Select Dendrobium officinale cultivated in the tea area of Songtao Miao Autonomous County, Fanjingshan as the material. Wash 2.5 kg of fresh Dendrobium officinale stems, cut them into oblique slices. The length of the oblique slices is 1 - 2 cm and the thickness is 2 - 3 mm. Dry the oblique slices in a drying oven at 50 °C until the moisture content is below 5%. Then use low-temperature ultrafine grinding technology to crush and break the dried oblique slices. When crushing and breaking, the temperature is -13 ± 1 °C and the powder discharging temperature is -13 ± 1 °C. The particle size of the discharged powder is 10 - 25 μm. Pass through a 200-mesh pharmacopoeia sieve to obtain the ultrafine powder of Dendrobium officinale, and store it sealed at room temperature for later use.

[0043] (2) Preparation of fermented black tea: Select Fuding Dabaicha cultivated in the tea area of Songtao Miao Autonomous County, Fanjingshan as the material, and carry out fermentation with reference to the processing technical regulations of "Fanjingshan Black Tea" (DB52 / T1012—2015): Wilting the fresh leaves of Fuding Dabaicha with one bud and two leaves after cleaning at room temperature with a relative humidity of 55 - 60% for 17 h. Knead and fix the wilted tea leaves with a kneading machine for 2 h. Ferment the fixed tea leaves at room temperature with a relative humidity of 55 - 60% for 4 h to obtain fermented black tea. Weigh a certain mass of the fermented black tea, gently knead it by hand for 5 min. Dry the kneaded tea leaves at 85 °C for 90 min. After cooling to room temperature, pass through a 200-mesh pharmacopoeia sieve, and gently sieve to remove the fine powder to obtain the dried fermented black tea. Weigh it again, calculate the water loss of the fermented tea leaves, and obtain the humidity of the fermented black tea. The humidity of the fermented black tea is 71.27 ± 0.64%, meeting the requirements.

[0044] (3) Preparation of Fanjingshan black tea in frost form: Evenly sprinkle the ultrafine powder of Dendrobium officinale obtained in step (1) into the fermented black tea obtained in step (2). The mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is 500:70. Gently knead it by hand for 5 min, then dry it at 85 °C for 90 min. After cooling to room temperature, gently sieve it with a 200-mesh pharmacopoeia sieve to remove the ultrafine powder of Dendrobium officinale that has not adhered to the tea leaves, and obtain the tea leaves with yellowish-white Dendrobium particles evenly adhered to the surface, that is, Fanjingshan black tea in frost form. Example 2:

[0045] (1) Preparation of ultrafine powder of Dendrobium officinale: Select the Fanjingshan Dendrobium officinale cultivated in the tea area of Songtao Miao Autonomous County, Fanjingshan as the material. Wash 2.5 kg of fresh Fanjingshan Dendrobium officinale stems, cut them into oblique slices. The length of the oblique slices is 1 - 2 cm and the thickness is 2 - 3 mm. Dry the oblique slices in a drying oven at 50 °C until the moisture content is below 5%. Then use the low-temperature ultrafine grinding technology to crush and break the dried oblique slices. When crushing and breaking, the temperature is -13 ± 1 °C and the powder discharging temperature is -13 ± 1 °C. The particle size of the discharged powder is 10 - 25 μm. Pass through a 200-mesh pharmacopoeia sieve to obtain the ultrafine powder of Dendrobium officinale, and store it sealed at room temperature for later use.

[0046] (2)Prepare fermented black tea: Select the Fuding Dabaicha cultivated in the tea area of Songtao Miao Autonomous County, Fanjingshan as the material, and carry out fermentation with reference to the processing technical regulations of "Fanjingshan Black Tea" (DB52 / T1012—2015): Wither the fresh leaves of Fuding Dabaicha with one bud and two leaves after cleaning at room temperature with a relative humidity of 55 - 60% for 17 h. Knead and fix the withered tea leaves repeatedly with a kneading machine for 2 h. Ferment the fixed tea leaves at room temperature with a relative humidity of 55 - 60% for 4 h to obtain fermented black tea. Weigh a certain mass of the fermented black tea, gently knead it by hand for 5 min. Dry the kneaded tea leaves at a temperature of 85 °C for 90 min. After cooling to room temperature, pass through a 200-mesh pharmacopoeia sieve, and gently sieve to remove the fine powder to obtain the dried fermented black tea. Weigh it again, calculate the water loss of the fermented tea leaves, and obtain the humidity of the fermented black tea. The humidity of the fermented black tea is 71.27 ± 0.64%, meeting the requirements.

[0047] (3)Prepare frost-like Fanjingshan black tea: Evenly sprinkle the ultrafine powder of Dendrobium officinale obtained in step (1) into the fermented black tea obtained in step (2). The mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is 500:70. Gently knead it by hand for 5 min, and then dry it at a temperature of 85 °C for 90 min. After cooling to room temperature, gently sieve it with a 200-mesh pharmacopoeia sieve to remove the ultrafine powder of Dendrobium that does not adhere to the tea leaves, and obtain the tea leaves with yellowish-white Dendrobium particles evenly adhered to the surface, that is, frost-like Fanjingshan black tea.

[0048] The above examples are only to illustrate the technical concept and technical characteristics of the present invention, and should not be used to limit the protection scope of the present invention. All equivalent transformations or modifications made according to the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing frosty Fanjingshan black tea with stomach-tonifying and kidney-invigorating functions, characterized in that: The following steps are involved: (1) Preparation of ultrafine powder of Dendrobium officinale: Wash the fresh stems of Fanjingshan Dendrobium officinale and cut them into oblique slices, place the oblique slices in a drying oven to dry, then use low-temperature ultrafine grinding technology to crush and break the dried oblique slices of Dendrobium officinale, sieve to obtain ultrafine powder of Dendrobium officinale, and seal and store them at room temperature for standby use; (2) Preparation of fermented black tea: The cleaned "one bud and two leaves" fresh leaves of Fuding Dabai tea are withered at room temperature, the withered tea leaves are repeatedly rolled and twisted with a rolling machine to kill the green, and the withered tea leaves are fermented at room temperature to obtain fermented black tea; (3) Preparation of frosted Fanjingshan black tea: The ultrafine powder of Dendrobium officinale obtained in step (1) is evenly sprinkled into the fermented black tea obtained in step (2), wherein the mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is 500:40-100, and the ultrafine powder of Dendrobium officinale is evenly mixed and adhered to the surface of the fermented black tea by gently twisting the mixture by hand, and then drying the mixture to make the ultrafine powder and the fermented black tea more closely adsorbed, and then sieving the mixture after cooling to room temperature, and lightly sieving the ultrafine powder of Dendrobium officinale that is not adhered to the fermented black tea to obtain tea leaves with yellow-white dendrobium particles evenly adhered to the surface, namely, frosted Fanjingshan black tea.

2. The preparation method according to claim 1, characterized in that: The Fanjingshan Dendrobium officinale described in step (1) is selected from the Fanjingshan Dendrobium officinale cultivated in the tea area of ​​Songtao Miao Autonomous County of Fanjingshan; the oblique slices are 1 to 2 cm long and 2 to 3 mm thick, and are dried in a drying oven at 50° C. to a moisture content of less than 5%.

3. The preparation method according to claim 1, characterized in that: In step (1), the dried oblique slices are crushed and broken by vacuum low-temperature ultrafine grinding technology, the crushing and breaking temperature is -13±1°C, the powder discharge temperature is -13±1°C, the particle size of the discharged powder is 10-25 μm, and the ultrafine powder of Dendrobium officinale is obtained by passing through a 200-mesh pharmacopoeia sieve.

4. The preparation method according to claim 1, characterized in that: In step (2), the Fuding Da Baicha is selected from the Fuding Da Baicha cultivated in the tea-growing area of ​​Songtao Miao Autonomous County, Fanjing Mountain, and is withered for 17 h at room temperature with a relative humidity of 55-60%. The withered tea leaves are repeatedly rolled and withered for 2 h using a rolling machine, and the withered tea leaves are fermented for 4 h at room temperature with a relative humidity of 55-60% to obtain fermented black tea.

5. The preparation method according to claim 1, characterized in that: In step (2), the humidity of the fermented black tea is 71.27 ± 0.64%, which meets the requirement.

6. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the fermented black tea to the ultrafine powder of Dendrobium officinale is 500:50-90.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the fermented black tea to the superfine powder of Dendrobium officinale is 500:70, and the mass ratio after drying is 145:

70.

8. The preparation method according to claim 1, characterized in that: In step (3), after the ultrafine powder of Dendrobium officinale is evenly sprinkled into the fermented black tea, it is gently twisted by hand for 5 minutes to make the ultrafine powder of Dendrobium officinale evenly mixed and adhere to the surface of the fermented black tea, and then baked at a temperature of 85°C for 90 minutes to make the ultrafine powder of Dendrobium officinale and the fermented black tea adsorb more closely. After cooling to room temperature, it is lightly sieved with a 200-mesh pharmacopoeia sieve to remove the ultrafine powder of Dendrobium officinale that is not adhered to the tea leaves, so as to obtain tea leaves with yellow-white Dendrobium officinale particles evenly adhered to the surface, that is, the frosty Fanjing Mountain black tea, which is named Fanjing "Frost" black tea in the present invention.

9. A frosty Fanjingshan black tea obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The daily dosage of the frosty Fanjingshan black tea is preferably 18-38 g.

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