Instant brick tea powder with reduced fluorine content and its manufacturing method

Abstract

To provide instant brick tea powder with reduced fluorine content and a method for producing the same. [Solution] The manufacturing method involves first freeze-drying fresh yuzu peel to remove moisture, followed by high-temperature carbonization to obtain carbonized yuzu peel material. Citric acid and sodium alginate are mixed to obtain a deep eutectic solvent. The carbonized yuzu peel material is then immersed in the deep eutectic solvent and dried to obtain the treated carbonized material. The treated carbonized material is then used in the manufacturing process of instant brick tea to obtain instant brick tea powder with a low fluorine content that does not affect the quality of the tea powder itself. The manufacturing method of the present invention is simple and amenable to large-scale industrial production.

Description

[Technical Field]

[0001] The present invention relates to instant brick tea powder with reduced fluorine content and a manufacturing method thereof, which belongs to the field of tea leaf processing technology. [Background technology]

[0002] Qingbrick tea, also known as bianjiao tea or brick tea, is a long-established pressed tea belonging to the black tea family. Named for its brick-like appearance, it is made from tea leaves that have undergone fermentation and post-fermentation processes. Qingbrick tea is popular for its unique flavor and health benefits. However, Qingbrick tea is typically made from older leaves, and most have a very high fluoride content, exceeding 350 mg / kg. A daily intake of more than 4 mg of fluoride can lead to fluoride poisoning and adverse health effects. Therefore, it is necessary to reduce the fluoride content in brick tea to broaden its application range.

[0003] Currently, defluoridation methods for tea leaves mainly include physical methods (membrane separation, adsorption), chemical methods (electrodialysis, the addition of fluoride-reducing agents), and biological methods (microbial defluoridation). Membrane separation (CN104543150A) separates fluoride by filtering tea extract through a 300-3000 Dalton membrane, while minimizing the loss of other chemical components in the tea, ensuring safety and reliability. Adsorption (Luo Xueping, Research on Fluoride Reduction Technology and Theory in Sichuan Black Tea [D], Sichuan Agricultural University, 2007) utilizes the adsorption properties of certain materials to remove fluoride from tea powder. Examples of adsorbents that can be used include activated carbon, zeolite, and alumina. Electrodialysis (Liu Haifeng, Research on Fluoride Ion Removal from Instant Brick Tea Using Electrodialysis Technology [D], Anhui Agricultural University, 2019) achieves defluoridation by using an electric field to directionally migrate fluoride ions through an electrodialysis device. The addition of fluoride-reducing agents (Xue Ping, Research on Fluoride Reduction Technology and Theory for Sichuan Black Tea [D], Sichuan Agricultural University, 2007) involves adding chemical fluoride-reducing agents, such as aluminum hydroxide and trisodium phosphate, to tea powder during processing. These fluoride-reducing agents react with the fluoride ions in the tea powder to form water-insoluble fluoride precipitates, thereby reducing the fluoride content in the tea powder. Microbial defluoridation utilizes the fluoride absorption and conversion abilities of certain microorganisms to reduce the fluoride content in tea powder. For example, some bacteria, fungi, and other microorganisms can absorb fluoride ions in tea powder into their cells or react with them through their metabolic products to achieve defluoridation. However, these methods are difficult to implement on a large scale, and defluoridation efficiency is low. For example, the adsorbent must be replaced frequently and the membrane size is limited. The quality of the tea powder is significantly affected. For example, the addition of foreign substances and the special procedures required result in significant losses of some beneficial components. These methods are costly and require additional equipment. Therefore, it is very important to find a method for producing tea powder that is simple to operate, allows for large-scale production, and does not affect the quality of the tea powder itself.

[0004] Instant tea is a fast-dissolving tea product made from finished tea, semi-finished tea, tea by-products, or fresh tea leaves, extracted and refined to remove water-soluble components. It contains the nutrients and flavoring substances that can be absorbed into tea water in traditional tea leaves, and has all the health benefits of tea. Instant tea, with its convenient and healthy characteristics, meets modern beverage consumption trends and is a beverage with a promising future.

[0005] Currently, few researchers are studying instant brick tea. Typical instant teas are made from key ingredients such as ginseng, Eucommia ulmoides, and vine leaves, or from teas such as Biluochun and black tea, which are rich in fragrance and theanine. For example, CN108713614A discloses a process for producing Biluochun instant tea, which has a strong aroma and high theanine content. Specifically, after infusing tea leaves, the instant tea is produced through processes such as centrifugation, membrane concentration, and vacuum freeze-drying. However, a large amount of aromatic components is lost during the infusion and vacuum freeze-drying processes, making it impossible to obtain a strong-fragrant instant tea. CN107348055A discloses a processing technology for producing fragrant cold-brewed instant tea and plant-based instant beverages, which involves extracting the aroma fraction and flavor solution from tea leaves, then centrifuging, concentrating, and spray-drying the flavor solution, and then adding the aroma fraction to a flavor-dried powder and freeze-drying it. This method not only requires separate extraction of the aroma fraction and flavor components from the tea leaves, making the process complicated, but also fails to solve the problem of the weak aroma of instant tea, as the aroma fraction added to the instant tea is highly volatile in the vacuum freeze-drying process.

[0006] Additionally, instant tea drinks typically require the addition of other substances to enhance color, flavor, and texture. For example, some all-in-one drinks combine tea water with flowers or fruits, sweeteners, thickeners, and colorants.

[0007] Therefore, how to produce instant brick tea powder with low fluorine content, simple operation, large-scale production, and without affecting the quality of the tea powder itself is an issue that needs to be solved urgently. Summary of the Invention [Problem to be solved by the invention]

[0008] Blue brick tea has a very high fluoride content. Conventional methods for defluorinating tea powder are difficult to achieve on a large scale industrial scale, have low defluorination efficiency, have a relatively large impact on the quality of tea powder, and are expensive. There are few researchers studying instant brick tea. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides an instant brick tea powder with reduced fluorine content and a method for producing the same. The present invention first freeze-dries fresh yuzu peel to remove moisture, and then carbonizes it at high temperature to obtain a carbonized yuzu peel material. Citric acid and sodium alginate are mixed to obtain a deep eutectic solvent. The carbonized yuzu peel material is then immersed in the deep eutectic solvent and dried to obtain a treated carbonized material. The treated carbonized material is then used in the instant brick tea production process to obtain an instant brick tea powder with a low fluorine content that does not affect the quality of the tea powder itself. The production method of the present invention is simple and amenable to large-scale industrial production.

[0010] The first object of the present invention is to provide a method for producing instant brick tea powder with reduced fluorine content, the method comprising: (1) freeze-drying fresh yuzu peel and carbonizing it at high temperature to obtain carbonized yuzu peel material; (2) uniformly mixing citric acid and sodium alginate in a molar ratio of 1-2:1-2 to obtain a deep eutectic solvent; (3) Immersing the carbonized yuzu peel material in a deep eutectic solvent and drying it to obtain a treated carbonized material; (4) adding the brick tea powder to water and extracting at 70-90°C for 0.5-1.5 hours, with the mass ratio of brick tea powder, water, and carbonized material after treatment being 1:8-20:0.001-0.005; then adding the carbonized material after treatment and adsorbing at 70-90°C for 5-10 minutes to obtain an extract; (5) centrifuging the extract and drying it to obtain instant brick tea powder.

[0011] In one embodiment of the present invention, the freeze-drying in step (1) is performed at -60°C to -20°C for 10 to 20 hours.

[0012] In one embodiment of the present invention, the high-temperature carbonization in step (1) involves placing the material in a muffle furnace, heating it to 850-950°C at a rate of 3-8°C / min under a nitrogen atmosphere, and maintaining the temperature for 1-3 hours.

[0013] In one embodiment of the present invention, the uniform mixing in step (2) is performed at 65 to 75°C and 300 to 500 rpm for 1 to 3 hours.

[0014] In one embodiment of the present invention, the mass ratio of the carbonized yuzu peel material to the deep eutectic solvent in step (3) is 1:2-4.

[0015] In one embodiment of the present invention, the immersion in step (3) is performed at 20 to 30° C. for 3 to 5 hours.

[0016] In one embodiment of the present invention, the drying in step (3) is natural drying.

[0017] In one embodiment of the present invention, for the brick tea powder in step (4), the green brick tea is decomposed to obtain a decomposed blue brick tea block having a size of 1 cm x 1 cm to 3 cm x 3 cm, and then the block is pulverized to obtain a blue brick tea powder having a mesh number of 40 to 60 mesh.

[0018] In one embodiment of the present invention, the centrifugation in step (5) can be performed at 7000 to 9000 rpm for 1 to 5 minutes.

[0019] In one embodiment of the present invention, the drying in step (5) is performed at 160 to 200° C. for 0.5 to 1.5 hours.

[0020] A second object of the present invention is an instant brick tea powder with reduced fluorine content, which is produced by the method according to the present invention.

[0021] The third object of the present invention is to apply the instant brick tea powder according to the present invention to the food field.

[0022] A fourth object of the present invention is to provide a tea drink using the instant brick tea powder according to the present invention. [Effects of the Invention]

[0023] (1) The defluoridation rate of the instant brick tea powder produced by the present invention is 90% or more, and the quality of the instant brick tea powder is not affected. There is almost no loss of the main components (tea polyphenols, catechins, caffeine, etc.), and there is even a slight increase. (2) The production method of the present invention is simpler, does not require multiple filtrations, does not require expensive equipment, is low cost, and allows for large-scale industrial production. (3) When the instant brick tea powder of the present invention is used to produce instant tea beverages, it can impart a citric acid aroma, allowing fewer additives to be used. (4) The instant tea beverage produced from the instant brick tea powder of the present invention can be dissolved in cold water or hot water, and has a wider range of applications. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of the present invention are described below, and it should be understood that the examples are provided to better illustrate the present invention and are not intended to limit the present invention. Testing method:

[0025] 1. Defluoridation rate test: GB / T21728-2008《Detection method for fluorine content in brick tea》

[0026] 2. Main component content and elemental analysis test: Measurement of tea polyphenols, catechins and caffeine content: Refer to the Chinese national standard GB / T8313-2018 "Method for detecting tea polyphenols and catechins content in tea leaves"

[0027] Raw materials used in the examples: Fresh yuzu peel: obtained by removing the pulp from commercially available yuzu (including the white and yellow peel), with a moisture content of 86-90%.

[0028] The method for producing blue brick tea powder is as follows: The blue brick tea was decomposed to obtain blue brick tea blocks measuring 1 cm x 1 cm to 3 cm x 3 cm, which were then crushed to obtain blue brick tea powder with a mesh number of 40 to 60 mesh. Blue brick tea: purchased from Hubei Zhao Liqiao Tea Factory Co., Ltd.

[0029] Example 1 A method for producing instant brick tea powder with reduced fluorine content, comprising the steps of: (1) Fresh yuzu peel was freeze-dried at -40°C for 12 hours, removed, placed in a muffle furnace, and heated to 900°C at a rate of 5°C / min under a nitrogen atmosphere. The temperature was maintained for 2 hours, and after carbonization was completed, the material was allowed to cool to room temperature, yielding a carbonized yuzu peel material. (2) Citric acid and sodium alginate were mixed in a molar ratio of 1:1 at 70 ° C. and 400 rpm for 2 hours, and then cooled to obtain a deep eutectic solvent. (3) The carbonized yuzu peel material was placed in the deep eutectic solvent so that the mass ratio of the carbonized yuzu peel material to the deep eutectic solvent was 1:3, and the material was immersed at room temperature (25°C) for 4 hours and then naturally dried to obtain the carbonized material after the treatment. (4) The brick tea powder was added to water so that the mass ratio of the brick tea powder, water, and carbonized material after treatment was 1:10:0.003, and the mixture was extracted at 80°C for 1 hour. The carbonized material after treatment was then added and adsorbed at 80°C for 10 minutes to obtain an extract. (5) The extract was centrifuged at 8000 rpm for 3 minutes and dried at 180°C for 1 hour to obtain instant brick tea powder.

[0030] Example 2 Instant brick tea powder was obtained in the same manner as in Example 1, except that the mass ratio of brick tea powder, water, and carbonized material after treatment in step (4) of Example 2 was adjusted to 1:10:0.001.

[0031] Example 3 An instant brick tea powder was obtained in the same manner as in Example 1, except that the mass ratio of the brick tea powder, water, and carbonized material after the treatment in step (4) of Example 2 was adjusted to 1:10:0.005.

[0032] Example 4 An instant brick tea powder was obtained in the same manner as in Example 1, except that the molar ratio of citric acid to sodium alginate in step (2) of Example 2 was adjusted to 1:2.

[0033] Comparative Example 1 An instant brick tea powder was obtained in the same manner as in Example 1, except that steps (1) to (3) of Example 1 were omitted.

[0034] Comparative Example 2 An instant brick tea powder was obtained in the same manner as in Example 1, except that step (2) in Example 1 was omitted and the deep eutectic solvent in step (3) was adjusted to water.

[0035] Comparative Example 3 Steps (1) and (3) of Example 1 were omitted, and the carbonized material after the treatment in step (4) was adjusted to a deep eutectic solvent. Otherwise, the same procedure as in Example 1 was carried out to obtain instant brick tea powder.

[0036] Comparative Example 4 The fresh yuzu peel in step (1) of Example 1 was prepared into a loofah, and the rest of the procedure was the same as in Example 1 to obtain instant brick tea powder.

[0037] Comparative Example 5 An instant brick tea powder was obtained in the same manner as in Example 1, except that sodium alginate in step (2) of Example 1 was changed to ethylene glycol.

[0038] Comparative Example 6 An instant brick tea powder was obtained in the same manner as in Example 1, except that the citric acid in step (2) of Example 1 was changed to betaine.

[0039] Comparative Example 7 Step (4) of Example 1 was adjusted as follows: The brick tea powder was added to water so that the mass ratio of the brick tea powder, water, and carbonized material after treatment was 1:10:0.003, and the carbonized material after treatment was added at the same time. Extraction was carried out at 80°C for 1 hour to obtain an extract. Other than that, the same procedure as in Example 1 was carried out to obtain instant brick tea powder.

[0040] The instant brick tea powders obtained in the Examples and Comparative Examples were subjected to performance tests, and the test results are as follows:

[0041] JPEG0007735017000001.jpg67170JPEG0007735017000002.jpg21170

[0042] The instant brick tea powder prepared in Example 1 was easily dissolved in cold water and hot water (within 10 seconds) after use in tea beverages, and the tea water after dissolution was clear and transparent, the aroma was well maintained, and there was no significant difference in dissolution between hot water and cold water.

[0043] Although the present invention has been disclosed in the form of preferred embodiments as described above, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined based on the definition of the following claims.

Claims

1. (1) freeze-drying fresh yuzu peel and carbonizing it at high temperature to obtain carbonized yuzu peel material; (2) uniformly mixing citric acid and sodium alginate in a molar ratio of 1-2:1-2 to obtain a deep eutectic solvent; (3) immersing the carbonized yuzu peel material in a deep eutectic solvent and drying it to obtain a treated carbonized material; (4) adding the brick tea powder to water and extracting at 70-90°C for 0.5-1.5 hours, with the mass ratio of brick tea powder, water, and carbonized material being 1:8-20:0.001-0.005; then adding the carbonized material and adsorbing at 70-90°C for 5-10 minutes to obtain an extract; (5) centrifuging the extract and drying it to obtain instant brick tea powder; 1. A method for producing instant brick tea powder with reduced fluorine content, comprising:

2. The method according to claim 1, wherein the freeze-drying in step (1) is carried out at -60°C to -20°C for 10 to 20 hours.

3. The method according to claim 1, wherein the high-temperature carbonization in step (1) is performed by placing the material in a muffle furnace under a nitrogen atmosphere, heating the material to 850 to 950°C at a heating rate of 3 to 8°C / min, and maintaining the temperature for 1 to 3 hours.

4. 2. The method according to claim 1, wherein the homogenous mixing in step (2) is performed at 65 to 75°C and 300 to 500 rpm for 1 to 3 hours.

5. 2. The method of claim 1, wherein the mass ratio of the carbonized yuzu peel material to the deep eutectic solvent in step (3) is 1:2-4.

6. 2. The method according to claim 1, wherein the soaking in step (3) is performed at 20 to 30° C. for 3 to 5 hours.

7. 2. The method according to claim 1, wherein the centrifugation in step (5) is performed at 7000 to 9000 rpm for 1 to 5 minutes.

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