Green tea juice, tea beverage and preparation method thereof

Abstract

The invention provides green tea juice, a tea beverage and a preparation method thereof. The preparation method of the green tea juice comprises the following steps: (1) mixing metal yeast powder, an antioxidant, first RO (Reverse Osmosis) water and green tea leaves in a semi-closed extraction device, performing primary extraction, and then supplementing and adding second RO water for secondary extraction to obtain a green tea extract; and (2) sequentially carrying out rapid cooling treatment, centrifugal treatment and filtration treatment on the green tea extract, and storing the green tea extract by adopting a liquid nitrogen storage device to obtain the green tea juice. The green tea juice obtained by comprehensively utilizing a multi-temperature-layer continuous extraction technology and RO water with extremely low dissolved oxygen content is rich and natural in green tea fragrance, sweet, mellow and fresh in taste, free of bitter and astringent taste and earthy taste, mellow and clean in taste and dark green in color and luster, and the best tea juice flavor can be achieved; and the obtained tea beverage has a relatively long shelf life under a normal-temperature placement condition, and meanwhile, the tea aroma is stable and does not fission, so that excellent quality is provided for consumers.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing and relates to a green tea extract, in particular to a green tea juice, a tea beverage and a preparation method thereof. Background Art

[0002] After nearly a decade of rapid development, the tea beverage market has reached hundreds of billions of yuan in annual sales, especially the popularity of sugar-free tea and milk tea beverages in recent years. It is necessary to develop different products to meet the growing needs of consumers. After market research, the development of green tea milk tea (or jasmine green tea beverage) meets the needs of market development.

[0003] Green tea-based milk tea is different from black tea milk tea and oolong tea milk tea. It has a jasmine fragrance, light tea flavor, and is refreshing without being greasy. It has become a popular product. Consumers have higher and higher requirements for milk tea, requiring milk tea to have a smooth taste, strong milk flavor, and a good balance between tea and milk. At present, the number of milk tea products with green tea juice as the base in street shops is increasing, and they are becoming more and more popular with consumers. Among them, the popular product "Jasmine Milk White" has an annual sales of more than 690,000 cups, which has the fragrance of green tea, mellow milk flavor, and natural and fresh characteristics. It is of great significance to develop ready-to-drink green tea milk tea to bring more satisfaction to consumers' taste buds.

[0004] At present, the common preparation methods of green milk tea include: first, selecting green tea leaves that have been specially processed as milk tea raw materials (such as infrared treatment); second, adding tea leaves directly into an open extraction container for high-temperature extraction, after tea leaves are extracted, tea residues are separated, antioxidants (vitamin C, sodium D-isoascorbate, etc.) are added to the tea juice for color protection, and then cooled and centrifuged to obtain tea juice. When blending with dairy products, a lower sterilization temperature is used to make a refrigerated milk tea beverage with a short shelf life, or the sterilization temperature is reduced to a high level, and cleaning is strengthened after scaling; third, the tea leaves are placed in a closed anaerobic extraction container under pressurized conditions, and the spraying device of the closed extraction container is used to spray water to clean the green tea leaves and spray extraction at different temperatures.

[0005] As is known to all, there are two major problems in the production process of green milk tea: 1) Tea polyphenols such as catechins in green tea leaves have strong reducing properties due to the presence of multiple hydroxyl groups, and they form oxidative polymerization with highly oxidizing substances. Affected by multiple factors such as oxygen, light, moisture, temperature and other conditions, they are easily oxidized and turned red. The higher the ambient temperature, the more intense the oxidation, resulting in the system to form brown and reddish brown discoloration. The beverages made with green tea as the base have large color changes and serious browning during the shelf life; 2) Since the aroma is easily lost during the extraction of green tea leaves, and the dissolution of soluble solids is low, if dairy raw materials are added, the aroma and flavor are low, and the tea feeling and tea aroma are not easy to express. In the production process, the tea feeling is improved by increasing the extraction time and extraction temperature, which leads to excessive dissolution of caffeine, tea polyphenols, and colloid substances in the green tea juice, which are easy to bind to proteins. In the high-temperature sterilization stage of production, the product sterilization tube is easy to scale, and it needs to be shut down for cleaning continuously, and it cannot be continuously produced for a long time, resulting in low production efficiency.

[0006] In order to overcome the shortcomings that still exist in the above-mentioned prior art, it is necessary to provide a tea extraction method with a high tea yield and a long shelf life, while ensuring that the tea aroma is stable without fission, so as to provide consumers with excellent quality tea drinks. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a green tea juice, a tea beverage and a preparation method thereof. The present invention utilizes a multi-temperature layer extraction process to retain the essence of tea leaves to the greatest extent, reduces the miscellaneous flavors and peculiar smells caused by oxygen and high temperature cracking, and makes the green tea juice have a rich and full aroma, a mellow and clean taste, a mild bitter taste with a sweet aftertaste, and a green color; in addition, the preparation method not only provides a method for improving continuous production efficiency, but also has a high tea extraction rate.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing green tea juice, the preparation method comprising the following steps:

[0010] (1) mixing metal yeast powder, antioxidant, first RO water and green tea leaves in a semi-enclosed extraction device, performing a primary extraction, and then adding a second RO water for secondary extraction to obtain a green tea extract;

[0011] (2) The green tea extract obtained in step (1) is subjected to rapid cooling, centrifugation and filtration in sequence, and then stored in a liquid nitrogen storage device to obtain the green tea juice.

[0012] The present invention utilizes multi-temperature layer continuous extraction technology to retain the essence of tea leaves to the greatest extent, while enhancing the fresh aroma of tea juice, reducing the impurities produced by cracking and oxidation of tea juice, and reducing the yield of bitter substances, so that the green tea juice has a fresh and rising aroma, a fresh taste, a mellow and clean mouthfeel, and a green color, and further improves the tea extraction rate. In addition, the green tea juice provided by the present invention has a long shelf life under room temperature conditions, while ensuring that the tea aroma therein is stable without fission, and the appearance and color are better, providing consumers with excellent quality.

[0013] Preferably, the green tea leaves include any one of scented tea leaves (green tea blank), fried green tea, baked green tea, steamed green tea or sun-dried green tea.

[0014] Preferably, the semi-enclosed extraction device in step (1) is a kneadar-type tea extraction kettle with a top cover, and the cover can be half open.

[0015] As a preferred technical solution of the present invention, the metal content in the metal yeast powder in step (1) is 8000-12000 ppm, for example, it can be 8000 ppm, 9000 ppm, 10000 ppm, 11000 ppm or 12000 ppm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, the metal yeast powder in step (1) comprises any one of iron yeast, zinc yeast or aluminum yeast, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of iron yeast and zinc yeast, a combination of iron yeast and aluminum yeast, a combination of zinc yeast and aluminum yeast, or a combination of iron yeast, zinc yeast and aluminum yeast.

[0017] Preferably, the mass proportion of the metal yeast powder in step (1) is 0.5-1% of the green tea leaves, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the antioxidant in step (1) comprises sodium D-isoascorbate and / or vitamin C.

[0019] Preferably, the mass proportion of the antioxidant in step (1) is 3-6% of the green tea leaves, for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5% or 6%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] In the present invention, the purpose of mixing the metal yeast powder and the antioxidant in the process of extracting the green tea extract is to use the metal yeast to slow down the replacement of magnesium in the chlorophyll molecule by hydrogen atoms to generate brown pheophytin, and at the same time, the antioxidant is used to superimpose the antioxidant effect, slowing down the discoloration reaction of chlorophyll and easily oxidized substances in the production and storage of the tea extract and the tea beverage prepared therefrom, thereby playing a color protection role;

[0021] More specifically, if the dosage of the metal yeast powder and antioxidant is too low, the tea juice will oxidize faster, browning will intensify, and the green tea flavor will be lost faster; if the dosage is too high, the tea juice will have an unpleasant yeast flavor and a sour taste.

[0022] As a preferred technical solution of the present invention, in step (1), the oxygen content of the first RO water and the second RO water are both ≤1 mg / L, for example, 1 mg / L, 0.8 mg / L, 0.6 mg / L, 0.4 mg / L or 0.2 mg / L, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] The dissolved oxygen content of the RO water used in the process of extracting the green tea extract of the present invention is extremely low. If the dissolved oxygen content of the RO water is too high, the color of the extract will change greatly, and the flavor of the extracted tea juice will be poor.

[0024] Preferably, the temperature of the first RO water in step (1) is 70-80°C, for example, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the amount of the first RO water added in step (1) is 20 to 30 times the mass of the green tea leaves, for example, 20 times, 22 times, 24 times, 26 times, 28 times or 30 times, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the extraction time in step (1) is 4 to 8 minutes, for example, 4 minutes, 5 minutes, 6 minutes, 7 minutes or 8 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the temperature of the second RO water in step (1) is 0-20°C, for example, 0°C, 4°C, 8°C, 12°C, 16°C or 20°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the amount of the second RO water added in step (1) is 8 to 15 times the mass of the green tea leaves, for example, 8 times, 10 times, 12 times, 14 times or 15 times, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the time of the secondary extraction in step (1) is 2 to 6 minutes, for example, 2 minutes, 3 minutes, 4 minutes, 5 minutes or 6 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] The extraction method adopted by the present invention is a multi-temperature layer continuous extraction technology, wherein the temperature of the first extraction is higher than the temperature of the second extraction; the characteristic aroma of tea is extracted by the first extraction; and the fresh tea feeling is extracted by the second extraction;

[0031] More specifically, when the temperature of the first extraction is too high, the aroma of the green tea juice will be lost quickly during the extraction process, the aroma retention will be low, and there will be a stewed taste. When the temperature of the first extraction is too low, it will lead to insufficient aroma extraction, weak aroma, and bitter substances will be dissolved to affect the taste. When the temperature of the second extraction is too high, the bitterness of the tea juice will be enhanced and the flavor will be unpleasant. When the temperature of the second extraction is too low, the tea juice will have a weak taste and a bland taste.

[0032] As a preferred technical solution of the present invention, the terminal temperature of the rapid cooling treatment in step (2) is 2 to 15°C, for example, it can be 2°C, 5°C, 8°C, 11°C, 13°C or 15°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the cooling rate of the rapid cooling treatment in step (2) is 25 to 35°C / min, for example, it can be 25°C / min, 27°C / min, 29°C / min, 31°C / min, 33°C / min or 35°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, the accuracy of the filter used in the filtration treatment in step (2) is 0.5 to 1 μm, for example, it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the liquid nitrogen storage device in step (2) comprises a storage barrel to which liquid ammonia is added.

[0036] In the present invention, the purpose of using a liquid nitrogen storage device to store the obtained green tea juice is to ensure that the tea juice is stored at a low temperature, extremely low oxygen or anaerobic state, so as to reduce flavor changes and tea juice oxidation caused by thermal reactions and oxidation reactions.

[0037] In a second aspect, the present invention provides a green tea juice, which is obtained by the preparation method provided in the first aspect.

[0038] In a third aspect, the present invention provides a tea beverage, wherein the tea beverage comprises the green tea juice provided in the second aspect of the present invention.

[0039] Preferably, the tea beverage comprises green tea-based milk tea.

[0040] As a preferred technical solution of the present invention, the tea beverage includes, by mass percentage: 10-50wt% green tea juice, 0-6wt% milk powder, 1-6wt% edible oil and fat product, 0-10wt% white sugar, 0-3wt% emulsifier, 0-2wt% buffer salt, 0-0.2wt% stabilizer, and the balance is RO water.

[0041] Exemplarily, the content of green tea juice in the tea beverage is 10-15wt%, for example, it can be 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0042] The content of milk powder in the tea beverage is 0-6wt%, for example, 0wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt% or 6wt%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0043] The content of the edible oil product in the tea beverage is 1-6wt%, for example, 1wt%, 2wt%, 3wt%, 4wt%, 5wt% or 6wt%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable;

[0044] The content of white sugar in the tea beverage is 0-10wt%, for example, it can be 0wt%, 2wt%, 4wt%, 6wt%, 8wt% or 10wt%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable;

[0045] The content of the emulsifier in the tea beverage is 0-3wt%, for example, it can be 0wt%, 1wt%, 2wt% or 3wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0046] The content of the buffer salt in the tea beverage is 0-2wt%, for example, it can be 0wt%, 0.5wt%, 1wt%, 1.5wt% or 2wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0047] The content of the stabilizer in the tea beverage is 0-0.2wt%, for example, it can be 0wt%, 0.05wt%, 0.1wt%, 0.15wt% or 0.2wt%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] Preferably, the edible fat and oil product comprises fat and / or solid beverage.

[0049] Preferably, the oil comprises any one or a combination of two of coconut oil, palm oil, animal fat or fat powder. Typical but non-limiting combinations include: a combination of coconut oil and palm oil, a combination of coconut oil and animal fat, a combination of palm oil and fat powder, a combination of animal fat and fat powder, or a combination of coconut oil, palm oil, animal fat and fat powder.

[0050] It is worth noting that, when the raw materials for preparing the tea beverage include solid beverages, the content of the milk powder, white sugar, emulsifier, buffer salt and stabilizer may be 0wt%.

[0051] Preferably, the emulsifier comprises mono- and di-glycerol fatty acid esters and / or sucrose esters.

[0052] Preferably, the buffer salt comprises any one of sodium carbonate, sodium bicarbonate, sodium tripolyphosphate, disodium hydrogen phosphate, sodium citrate, sodium hexametaphosphate or dipotassium hydrogen phosphate, or a combination of at least two thereof. Typical but non-limiting combinations include: a combination of sodium carbonate and sodium bicarbonate, a combination of sodium tripolyphosphate, disodium hydrogen phosphate and sodium hexametaphosphate, or a combination of sodium citrate and dipotassium hydrogen phosphate.

[0053] Preferably, the stabilizer comprises any one of carrageenan, microcrystalline cellulose, sodium carboxymethyl cellulose or guar gum, or a combination of at least two thereof. Typical but non-limiting combinations include: a combination of carrageenan and guar gum, a combination of microcrystalline cellulose and sodium carboxymethyl cellulose, or a combination of carrageenan, microcrystalline cellulose, sodium carboxymethyl cellulose and guar gum.

[0054] In a fourth aspect, the present invention provides a method for preparing the tea beverage provided in the third aspect, wherein the preparation method is carried out in a nitrogen-filled deoxygenation device and comprises the following steps:

[0055] (a) mixing green tea juice and buffer salt to obtain a first mixed solution; mixing deoxygenated RO water and an emulsifier to dissolve them once, mixing milk powder and an edible oil product to dissolve them twice, and performing a homogenization treatment to obtain a second mixed solution;

[0056] (b) mixing the first mixed solution, the second mixed solution and white sugar, and performing a secondary homogenization treatment after constant volume with deoxygenated RO water, and then performing sterilization treatment, cooling treatment and aseptic canning in sequence to obtain the tea beverage.

[0057] It is worth noting that before mixing and preparing tea beverages, the nitrogen-filled deoxygenation device needs to be deoxygenated. The purpose of using the nitrogen-filled deoxygenation device is to provide a deoxygenated environment during the preparation of tea beverages to reduce the impact of oxidation reactions on product stability and improve the shelf life stability of the product. In addition, during the aseptic filling process of step (b), the filling device needs to be treated with nitrogen blowing and nitrogen dripping to achieve a deoxygenated environment.

[0058] As a preferred technical solution of the present invention, the pH value of the first mixed solution in step (a) is 6.8-7.2, for example, it can be 6.8, 6.9, 7.0, 7.1 or 7.2, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] Preferably, the mass ratio of the deoxygenated RO water to the milk powder in step (a) is 6 to 10:1, for example, 6:1, 7:1, 8:1, 9:1 or 10:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0060] Preferably, the temperature of the deoxygenated RO water in step (a) is 70-80°C, for example, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0061] Preferably, the time for one dissolution in step (a) is 3 to 5 minutes, for example, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0062] Preferably, the secondary dissolution time in step (a) is 18 to 22 minutes, for example, 18 minutes, 19 minutes, 20 minutes, 21 minutes or 22 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] Preferably, the pressure of the primary homogenization treatment in step (a) is 200-250 bar, for example, it can be 200 bar, 210 bar, 220 bar, 230 bar, 240 bar or 250 bar, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] As a preferred technical solution of the present invention, step (b) further includes dissolving and filtering the white sugar before mixing.

[0065] Preferably, the temperature for dissolving white sugar is 50-60°C, for example, 50°C, 52°C, 54°C, 56°C, 58°C or 60°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] Preferably, the accuracy of the filtration treatment is 150-200 mesh, for example, it can be 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh or 200 mesh, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0067] Preferably, the pressure of the secondary homogenization treatment in step (b) is 250-300 bar, for example, it can be 250 bar, 260 bar, 270 bar, 280 bar, 290 bar or 300 bar, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0068] Preferably, the temperature of the secondary homogenization treatment in step (b) is 65-75°C, for example, it can be 65°C, 67°C, 69°C, 71°C, 73°C or 75°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] It is worth noting that the maximum circuit pressure of the homogenizer used in the primary homogenization treatment and the secondary homogenization treatment is 50 bar.

[0070] Preferably, the sterilization treatment in step (b) is UHT sterilization, and the temperature of the UHT sterilization is 137-142°C, for example, it can be 137°C, 138°C, 139°C, 140°C, 141°C or 142°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0071] Preferably, the UHT sterilization time is 10 to 45 seconds, for example, 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds or 45 seconds, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0072] Preferably, the terminal temperature of the cooling treatment in step (b) is 25-30°C, for example, it can be 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0073] It is worth noting that the dissolved oxygen content of the deoxygenated RO water used in the preparation process of the tea beverage described in the present invention is ≤1 mg / L, for example, it can be 1 mg / L, 0.8 mg / L, 0.6 mg / L, 0.4 mg / L or 0.2 mg / L, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0074] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] (1) The present invention comprehensively utilizes multi-temperature layer continuous extraction technology and RO water with extremely low dissolved oxygen content, so that the obtained green tea juice has a strong and natural green tea aroma, a sweet and fresh taste, no bitterness and earthy taste, a mellow and clean taste, and a green color, and can achieve the best tea juice flavor;

[0077] (2) The present invention utilizes multi-temperature layer continuous extraction technology combined with RO water with extremely low dissolved oxygen content to overcome the defect that the tea aroma is easily oxidized and fissioned when the tea juice is extracted at high temperature and high pressure; thereby avoiding the phenomenon of tea beverage quality cracking and instability caused by increased bitterness of tea leaves or the generation of unpleasant and foreign flavors;

[0078] (3) The tea beverage prepared with the green tea juice provided by the present invention as the main raw material can be sold at room temperature. The color and flavor of the green tea (jasmine) milk tea are stable after 7 months, and the color and flavor of the product can also provide consumers with better quality after 9 months, which has broad market prospects. DETAILED DESCRIPTION

[0079] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0080] In a specific embodiment, the present invention provides a green tea juice and a preparation method thereof, the preparation method comprising the following steps:

[0081] (1) mixing metal yeast powder, antioxidant, first RO water and green tea leaves in a semi-enclosed extraction device, performing a primary extraction, and then adding a second RO water for secondary extraction to obtain a green tea extract;

[0082] The mass proportion of the metal yeast powder is 0.5-1% of the green tea leaves; the mass proportion of the antioxidant is 3-6% of the green tea leaves;

[0083] The oxygen content of the first RO water and the second RO water is ≤1 mg / L; the temperature of the first RO water is 70-80°C, and the amount added is 20-30 times the mass of green tea leaves; the time of the first extraction is 4-8 minutes;

[0084] The temperature of the second RO water is 0-20°C, and the amount added is 8-15 times the mass of the green tea leaves; the time of the secondary extraction is 2-6 minutes;

[0085] (2) The green tea extract obtained in step (1) is rapidly cooled to 2-15°C at a cooling rate of 25-35°C / min, then centrifuged, filtered through a filter with an accuracy of 0.5-1 μm, and stored in a liquid nitrogen storage device to obtain the green tea juice.

[0086] In another specific embodiment, the present invention provides a tea beverage comprising the green tea juice, wherein the tea beverage comprises, by mass percentage: 10-50wt% green tea juice, 0-6wt% milk powder, 1-6wt% edible oil product, 0-10wt% white sugar, 0-3wt% emulsifier, 0-2wt% buffer salt, 0-0.2wt% stabilizer, and the balance is RO water;

[0087] The preparation method of the tea beverage comprises the following steps:

[0088] (a) mixing green tea juice and buffer salt to obtain a first mixed solution with a pH value of 6.8 to 7.2; mixing RO water at a temperature of 70 to 80° C. and an emulsifier for primary dissolution for 3 to 5 minutes, mixing milk powder and edible oil products for secondary dissolution for 18 to 22 minutes, and then performing a homogenization treatment at a pressure of 200 to 250 bar to obtain a second mixed solution;

[0089] (b) mixing the first mixed solution, the second mixed solution and white sugar, and then performing a secondary homogenization treatment at a pressure of 250-300 bar and a temperature of 65-75° C. after adjusting the volume with RO water, and then performing a UHT sterilization treatment at 137-142° C. for 10-45 seconds, cooling to 25-30° C. and then aseptically canning to obtain the tea beverage.

[0090] Example 1

[0091] This embodiment provides a green tea juice, and the preparation method of the green tea juice comprises the following steps:

[0092] (1) mixing metal yeast powder, sodium D-isoascorbate, first RO water and green tea leaves in a semi-enclosed Kneada extraction device (half-covered), performing a primary extraction, and then adding a second RO water for a secondary extraction to obtain a green tea extract;

[0093] The mass proportion of the metal yeast powder is 0.7% of the green tea leaves; the mass proportion of the antioxidant is 4.5% of the green tea leaves;

[0094] The oxygen content of the first RO water and the second RO water is 1 mg / L; the temperature of the first RO water is 75° C., and the amount added is 25 times the mass of the green tea leaves; the time for one extraction is 5 minutes;

[0095] The temperature of the second RO water is 10°C, and the amount added is 10 times the mass of the green tea leaves; the time of the secondary extraction is 5 minutes;

[0096] (2) The green tea extract obtained in step (1) is rapidly cooled to 10° C. at a cooling rate of 30° C. / min, then centrifuged, filtered through a filter with an accuracy of 0.7 μm, and stored in a liquid nitrogen storage device to obtain the green tea juice.

[0097] Example 2

[0098] This embodiment provides a green tea juice, and the preparation method of the green tea juice comprises the following steps:

[0099] (1) mixing metal yeast powder, vitamin C, first RO water and green tea leaves in a semi-enclosed Kneada type extraction device (half-covered), performing a primary extraction, and then adding a second RO water for a secondary extraction to obtain a green tea extract;

[0100] The mass proportion of the metal yeast powder is 0.5% of the green tea leaves; the mass proportion of the antioxidant is 6% of the green tea leaves;

[0101] The oxygen content of the first RO water and the second RO water is 0.5 mg / L; the temperature of the first RO water is 70° C., and the amount added is 20 times the mass of green tea leaves; the time for one extraction is 4 minutes;

[0102] The temperature of the second RO water is 0°C, and the amount added is 8 times the mass of the green tea leaves; the time of the secondary extraction is 2 minutes;

[0103] (2) The green tea extract obtained in step (1) is rapidly cooled to 2°C at a cooling rate of 25°C / min, then centrifuged, filtered through a filter with an accuracy of 1 μm, and stored in a liquid nitrogen storage device to obtain the green tea juice.

[0104] Example 3

[0105] This embodiment provides a green tea juice, and the preparation method of the green tea juice comprises the following steps:

[0106] (1) mixing metal yeast powder, an antioxidant (sodium D-isoascorbate and vitamin C in a mass ratio of 1:1), a first RO water and green tea leaves in a semi-enclosed Kneada extraction device (half-covered), performing a primary extraction, and then adding a second RO water for a secondary extraction to obtain a green tea extract;

[0107] The mass proportion of the metal yeast powder is 1% of the green tea leaves; the mass proportion of the antioxidant is 3% of the green tea leaves;

[0108] The oxygen content of the first RO water and the second RO water is 1 mg / L; the temperature of the first RO water is 80° C., and the amount added is 30 times the mass of green tea leaves; the time for one extraction is 8 minutes;

[0109] The temperature of the second RO water is 20°C, and the amount added is 15 times the mass of the green tea leaves; the time of the secondary extraction is 6 minutes;

[0110] (2) The green tea extract obtained in step (1) is rapidly cooled to 15°C at a cooling rate of 35°C / min, then centrifuged, filtered through a filter with an accuracy of 0.5 μm, and stored in a liquid nitrogen storage device to obtain the green tea juice.

[0111] Example 4

[0112] This embodiment provides a green tea juice, and the preparation method of the green tea juice is different from that of embodiment 1 only in that:

[0113] In this embodiment, the oxygen content of the first RO water and the second RO water is adjusted to 1.5 mg / L.

[0114] Example 5

[0115] This embodiment provides a green tea juice, and the preparation method of the green tea juice is different from that of embodiment 1 only in that:

[0116] In this embodiment, the temperature of the first RO water in step (1) is adjusted to 60°C.

[0117] Example 6

[0118] This embodiment provides a green tea juice, and the preparation method of the green tea juice is different from that of embodiment 1 only in that:

[0119] In this embodiment, the temperature of the first RO water in step (1) is adjusted to 90°C, and the temperature of the second RO water is adjusted to 30°C.

[0120] Comparative Example 1

[0121] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0122] In this comparative example, the semi-enclosed extraction device in step (1) is adjusted to a fully enclosed extraction device.

[0123] Comparative Example 2

[0124] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0125] In this comparative example, the semi-enclosed extraction device in step (1) is adjusted to a fully open extraction device.

[0126] Comparative Example 3

[0127] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0128] In this comparative example, step (1) is adjusted as follows: metal yeast powder, antioxidant, RO water and green tea leaves are mixed in a semi-enclosed extraction device for 10 minutes of extraction;

[0129] The oxygen content of the RO water is 1 mg / L, the temperature is 75°C, and the added amount is 35 times the mass of green tea leaves.

[0130] Comparative Example 4

[0131] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0132] In this comparative example, step (1) is adjusted as follows: metal yeast powder, antioxidant, RO water and green tea leaves are mixed in a semi-enclosed extraction device for 10 minutes of extraction;

[0133] The oxygen content of the RO water is 1 mg / L, the temperature is 10°C, and the added amount is 35 times the mass of green tea leaves.

[0134] Comparative Example 5

[0135] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0136] In this comparative example, the liquid nitrogen storage device in step (2) is adjusted to a common storage barrel.

[0137] Comparative Example 6

[0138] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0139] In this comparative example, the addition of the metal yeast powder in step (1) was omitted, and the weight proportion of the antioxidant was adjusted to 5.2% of the green tea leaves.

[0140] Comparative Example 7

[0141] This comparative example provides a green tea juice, and the preparation method of the green tea juice is different from that of Example 1 only in that:

[0142] In this comparative example, the addition of the antioxidant described in step (1) was omitted, and the mass proportion of the metal yeast powder was adjusted to 5.2% of the green tea leaves.

[0143] Performance testing:

[0144] (1) The Lab values ​​of the green tea juices provided in the above embodiments and comparative examples were measured using a colorimetric instrument, and the results are shown in Table 1;

[0145] Among them, the L value represents the brightness of the tea soup. The higher the value, the brighter the tea soup. The a value represents red and green. +a represents reddish. The larger the value, -a represents greenish. The smaller the value, the darker the green. The b value represents yellow and blue. +b represents yellowish. The larger the value, the darker the yellow.

[0146] (2) The flavor of the green tea juices provided in the above examples and comparative examples was evaluated, and the caffeine content was tested. The results are shown in Table 2.

[0147] Table 1

[0148]

[0149]

[0150] Table 2

[0151]

[0152] According to Tables 1 and 2, the brightness of the green tea juice obtained through continuous extraction in multiple temperature layers is improved, the tea soup is relatively green, the dissolution rate of the bitter substance caffeine is reduced, and the freshness of the tea is improved.

[0153] Application Example 1

[0154] This application example provides a tea beverage, which includes, by mass percentage, 30wt% of green tea juice provided in Example 1, 3wt% of milk powder, 3wt% of coconut oil and solid beverage, 5wt% of white sugar, 1.5wt% of emulsifier (mono- and diglycerol fatty acid esters), 1wt% of buffer salt (sodium carbonate), 0.1wt% of stabilizer (carrageenan), and the balance is deoxygenated RO water;

[0155] The preparation method of the tea beverage comprises the following steps:

[0156] (a) mixing green tea juice and buffer salt to obtain a first mixed solution with a pH value of 7; mixing deoxygenated RO water at a temperature of 75° C. and an emulsifier for a primary dissolution for 4 minutes, mixing milk powder and an edible oil product for a secondary dissolution for 20 minutes, and then performing a homogenization treatment at a pressure of 250 bar to obtain a second mixed solution;

[0157] (b) mixing the first mixed solution, the second mixed solution and white sugar, and performing a secondary homogenization treatment at a pressure of 280 bar and a temperature of 70° C. after adjusting the volume with deoxygenated RO water, and then performing a UHT sterilization treatment at 140° C. for 30 seconds, cooling to 27° C. and then aseptically canning to obtain the tea beverage.

[0158] Application Example 2

[0159] This application example provides a tea beverage, which includes, by mass percentage, 10 wt% of green tea juice provided in Example 1, 0 wt% of milk powder, 6 wt% of solid beverage, 0 wt% of white sugar, 0 wt% of emulsifier, 0.2 wt% of buffer salt (sodium citrate), 0.1 wt% of stabilizer (guar gum), and the balance is deoxygenated RO water;

[0160] The preparation method of the tea beverage comprises the following steps:

[0161] (a) mixing green tea juice and buffer salt to obtain a first mixed solution with a pH value of 6.8; dissolving the mixture in deoxygenated RO water at a mixing temperature of 70° C. for 3 minutes, dissolving the mixture in an edible oil product for a second time for 18 minutes, and then homogenizing the mixture at a pressure of 200 bar to obtain a second mixed solution;

[0162] (b) mixing the first mixed solution and the second mixed solution, and performing a secondary homogenization treatment at a pressure of 250 bar and a temperature of 65° C. after adjusting the volume with deoxygenated RO water, and then performing a UHT sterilization treatment at 137° C. for 45 seconds, cooling to 25° C., and then aseptically canning to obtain the tea beverage.

[0163] Application Example 3

[0164] This application example provides a tea beverage, which includes, by mass percentage, 50wt% of green tea juice provided in Example 1, 6wt% of milk powder, 1wt% of animal fat, 8wt% of white sugar, 3wt% of emulsifier (sucrose ester), 2wt% of buffer salt (sodium tripolyphosphate), 0.2wt% of stabilizer (microcrystalline cellulose), and the balance is deoxygenated RO water;

[0165] The preparation method of the tea beverage comprises the following steps:

[0166] (a) mixing green tea juice and buffer salt to obtain a first mixed solution with a pH value of 7.2; mixing deoxygenated RO water at a temperature of 80° C. and an emulsifier for a primary dissolution for 5 minutes, mixing milk powder and an edible oil product for a secondary dissolution for 22 minutes, and then performing a homogenization treatment at a pressure of 220 bar to obtain a second mixed solution;

[0167] (b) mixing the first mixed solution, the second mixed solution and white sugar, and performing a secondary homogenization treatment at a pressure of 280 bar and a temperature of 75° C. after adjusting the volume with deoxygenated RO water, and then performing a UHT sterilization treatment at 142° C. for 10 to 45 seconds, cooling to 30° C. and then aseptically canning to obtain the tea beverage.

[0168] Application Example 4

[0169] This application example provides a tea beverage. The tea beverage is different from Application Example 1 only in that the green tea juice in this application example is adjusted to the green tea juice provided in Example 2.

[0170] The preparation method of the tea beverage is the same as that of Example 1.

[0171] Application Example 5

[0172] This application example provides a tea beverage. The tea beverage is different from Application Example 1 only in that the green tea juice in this application example is adjusted to the green tea juice provided in Example 4.

[0173] The preparation method of the tea beverage is the same as that of Example 1.

[0174] Comparative application example 1

[0175] This comparative application example provides a tea beverage, and the tea beverage is different from Application Example 1 only in that the green tea juice in this application example is adjusted to the green tea juice provided in Comparative Example 2.

[0176] The preparation method of the tea beverage is the same as that of Example 1.

[0177] Comparative Application Example 2

[0178] This comparative application example provides a tea beverage, and the tea beverage is different from Application Example 1 only in that the green tea juice in this application example is adjusted to the green tea juice provided in Comparative Example 3.

[0179] The preparation method of the tea beverage is the same as that of Example 1.

[0180] Comparative Application Example 3

[0181] This comparative application example provides a tea beverage, and the tea beverage is different from Application Example 1 only in that the green tea juice in this application example is adjusted to the green tea juice provided in Comparative Example 5.

[0182] The preparation method of the tea beverage is the same as that of Example 1.

[0183] Performance testing:

[0184] (a) Using a colorimetric instrument to detect the Lab of the tea beverages provided in some of the above application examples and comparative application examples over time, the results are shown in Table 3;

[0185] Table 3

[0186]

[0187]

[0188] (b) The overall flavor of the tea beverages provided by some of the above application examples and comparative application examples was evaluated, and the results are shown in Table 4;

[0189] The overall flavor evaluation adopts a seven-point system, specifically: 1 point - very poor; 2 points - relatively poor; 3 points - poor; 4 points - average; 5 points - good; 6 points - relatively good; 7 points - very good; * represents an unpleasant flavor, ☆ represents a relatively serious unpleasant flavor, and ★ represents a very serious unpleasant flavor.

[0190] Table 4

[0191]

[0192]

[0193] According to Tables 3 and 4, under room temperature conditions, the tea beverage prepared using the green tea juice provided by the present invention as the main raw material has stable color and flavor after 7 months, and the color and flavor of the product can also provide consumers with better quality after 9 months, and has broad market prospects.

[0194] In summary, the green tea juice obtained by the present invention through comprehensive utilization of multi-temperature layer continuous extraction technology and RO water with extremely low dissolved oxygen content has a strong and natural green tea aroma, a sweet and fresh taste, no bitterness and earthy taste, a mellow and clean taste, and a green color, which can achieve the best tea juice flavor; and the obtained tea beverage has a long shelf life under room temperature conditions, while ensuring that the tea aroma therein is stable without fission, providing consumers with excellent quality.

[0195] The applicant declares that the specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing green tea juice, characterized in that: The preparation method comprises the following steps: (1) mixing metal yeast powder, antioxidant, first RO water and green tea leaves in a semi-enclosed extraction device, performing a primary extraction, and then adding a second RO water for secondary extraction to obtain a green tea extract; (2) The green tea extract obtained in step (1) is subjected to rapid cooling, centrifugation and filtration in sequence, and then stored in a liquid nitrogen storage device to obtain the green tea juice.

2. The preparation method according to claim 1, characterized in that: The metal content in the metal yeast powder in step (1) is 8000-12000 ppm; Preferably, the mass proportion of the metal yeast powder in step (1) is 0.5-1% of the green tea leaves; Preferably, the antioxidant in step (1) comprises sodium D-isoascorbate and / or vitamin C; Preferably, the antioxidant in step (1) accounts for 3-6% of the mass of the green tea leaves.

3. The preparation method according to claim 1 or 2, characterized in that: Step (1) the oxygen content of the first RO water and the second RO water are both ≤1 mg / L; Preferably, the temperature of the first RO water in step (1) is 70-80° C.; Preferably, the amount of the first RO water added in step (1) is 20 to 30 times the mass of the green tea leaves; Preferably, the extraction time in step (1) is 4 to 8 minutes; Preferably, the temperature of the second RO water in step (1) is 0-20°C; Preferably, the amount of the second RO water added in step (1) is 8 to 15 times the mass of the green tea leaves; Preferably, the secondary extraction time in step (1) is 2 to 6 minutes.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The terminal temperature of the rapid cooling treatment in step (2) is 2 to 15°C; Preferably, the cooling rate of the rapid cooling treatment in step (2) is 25-35°C / min; Preferably, the filter used in the filtration process in step (2) has a precision of 0.5 to 1 μm.

5. A green tea juice, characterized in that: The green tea juice is obtained by the preparation method according to any one of claims 1 to 4.

6. A tea beverage, characterized in that: The tea beverage comprises the green tea juice according to claim 5; Preferably, the tea beverage comprises green tea-based milk tea.

7. The tea beverage according to claim 6, characterized in that In terms of mass percentage, the tea beverage comprises: 10-50wt% green tea juice, 0-6wt% milk powder, 1-6wt% edible oil and fat product, 0-10wt% white sugar, 0-3wt% emulsifier, 0-2wt% buffer salt, 0-0.2wt% stabilizer, and the balance is RO water; Preferably, the edible fat and oil product comprises fat and / or solid beverage; Preferably, the oil comprises any one of coconut oil, palm oil, animal fat or oil powder or a combination of two thereof; Preferably, the emulsifier comprises mono- and di-glycerol fatty acid esters and / or sucrose esters; Preferably, the buffer salt comprises any one or a combination of at least two of sodium carbonate, sodium bicarbonate, sodium tripolyphosphate, disodium hydrogen phosphate, sodium citrate, sodium hexametaphosphate or dipotassium hydrogen phosphate; Preferably, the stabilizer comprises any one of carrageenan, microcrystalline cellulose, sodium carboxymethyl cellulose or guar gum, or a combination of at least two thereof.

8. A method for preparing a tea beverage as claimed in claim 6 or 7, characterized in that: The preparation method is carried out in a nitrogen-filled deoxygenation device and comprises the following steps: (a) mixing green tea juice and buffer salt to obtain a first mixed solution; After mixing deoxygenated RO water and an emulsifier for a primary dissolution, mixing milk powder and an edible oil product for a secondary dissolution, and performing a homogenization treatment, a second mixed solution is obtained; (b) mixing the first mixed solution, the second mixed solution and white sugar, and performing a secondary homogenization treatment after constant volume with deoxygenated RO water, and then performing sterilization treatment, cooling treatment and aseptic canning in sequence to obtain the tea beverage.

9. The method for preparing a tea beverage according to claim 8, characterized in that: Step (a) The pH value of the first mixed solution is 6.8 to 7.2; Preferably, the mass ratio of the deoxygenated RO water to the milk powder in step (a) is 6 to 10:1; Preferably, the temperature of the deoxygenated RO water in step (a) is 70-80°C; Preferably, the pressure of the primary homogenization treatment in step (a) is 200-250 bar.

10. The method for preparing a tea beverage according to claim 8 or 9, characterized in that: Step (b) also includes dissolving and filtering the white sugar before mixing; Preferably, the pressure of the secondary homogenization treatment in step (b) is 250 to 300 bar; Preferably, the temperature of the secondary homogenization treatment in step (b) is 65-75°C; Preferably, the terminal temperature of the cooling treatment in step (b) is 25-30°C.

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