Method for preparing sterile concentrated tea extract with low dissolved oxygen level, tea extract, method for preparing ready-to-drink tea beverages, and tea beverages

Abstract

The present disclosure relates to sterile concentrated tea extracts and tea beverages with a low dissolved oxygen level. An example method includes steeping tea leaves in water to extract the tea leaves and obtain a steeped tea, separating the tea leaves from the steeped tea, cooling the steeped tea to room temperature to obtain an initial tea extract, removing dissolved oxygen until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower, and sterilizing the tea extract to obtain a sterile concentrated tea extract having a low dissolved oxygen level of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3. The method of the present disclosure can be used to achieve reduced oxidation of tea polyphenols, achieve a flavor close to that of freshly brewed tea, delay quality degradation, and lower production costs.

Description

METHOD FOR PREPARING STERILE CONCENTRATED TEA EXTRACT WITH LOW DISSOLVED OXYGEN LEVEL, TEA EXTRACT, METHOD FOR PREPARING READY-TO-DRINK TEA BEVERAGES, AND TEA BEVERAGESCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Chinese Patent Application No. 2023118379384, filed with the China National Intellectual Property Administration (CNIPA) on December 28, 2023, the disclosure of which is incorporated herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to a method for preparing tea extract, tea extract obtained by this method, a method for preparing tea beverages, and tea beverages obtained by this method. Specifically, the present disclosure relates to a method for preparing sterile concentrated tea extract with a low dissolved oxygen level, the sterile concentrated tea extract with a low dissolved oxygen level obtained through this method, a method for preparing ready-to-drink tea beverages, and the ready-to-drink tea beverages obtained through this method.BACKGROUND

[0003] Tea leaves, as a raw material for tea beverages, are rich in antioxidant substances such as tea polyphenols. The molecules of tea polyphenols contain phenolic hydroxyl groups, which can dissociate hydrogen ions (H+), thus exhibiting acidity. Tea polyphenols are easily oxidized, especially in aqueous solutions or in the presence of polyphenol oxidase. When phenolic hydroxyl groups dissociate, phenolate anions are generated, which can further lose electrons to produce ortho-quinones, which can oxidize other substances to be reduced back into phenols and can also undergo polymerization to produce reddish-brown polymers. Therefore, the prior artstrives to minimize the damage caused by oxygen to tea polyphenols and its adverse effects on tea beverage quality during the preparation of tea beverages. For example:

[0004] CN 10275471 IB discloses a tea beverage and its production method, which includes further measures such as "temporary storage tanks during the filtering or clarification process all using sealed tanks" and "introducing, in advance, > 99% pure nitrogen gas into a blending tank to replace the air inside the tank" as part of an "entire nitrogen-protected process," regardless of the cost.

[0005] JP 4411250B2 discloses a method for producing tea beverages that includes steps such as extracting tea leaves, adjusting the pH of the obtained tea extract to 5.0 to 6.0 to obtain a blending solution, mixing nitrogen gas with the blending solution under a negative pressure of at least 0.01 MPa, and then stabilizing the blending solution by maintaining it at atmospheric pressure for 30 seconds to 20 minutes after applying the negative pressure. However, the blending solution in JP 4411250B2 requires nitrogen replacement and stabilization under a negative pressure, which leads to long processing times, reduced production efficiency, and loss of aroma during the negative pressure treatment.

[0006] In summary, there is an urgent need for a tea beverage preparation method that can overcome the above shortcomings, especially a method that can simultaneously reduce the oxidation of tea polyphenols, preserve the flavor close to freshly brewed tea, achieve low contents of dissolved oxygen in the final product, delay quality degradation, and reduce production costs.SUMMARY OF THE DISCLOSURE

[0007] The technical problem that the present disclosure aims to solve is to overcome the following shortcomings of existing tea beverage preparation methods: the addition of large amounts of antioxidants, which affects the taste of the final product or exhaustive efforts to create a low dissolved oxygen environment, resulting in unnecessary aroma loss and excessively high production costs. The present disclosure provides a tea beverage preparation method that achieves good protection of tea polyphenols, uses a reasonable amount of antioxidants, providesa final product with a flavor close to freshly brewed tea, delays quality degradation, and lowers costs.

[0008] The inventors of the present disclosure unexpectedly discovered that by preparing a sterile concentrated tea extract with a low dissolved oxygen level, it is possible to strictly control the amount of dissolved oxygen. Additionally, by adjusting the preparation steps, it is unnecessary to excessively maintain or create an absolutely low dissolved oxygen condition, thereby simultaneously achieving the technical effects of preserving the taste of the final product, delaying quality degradation, and reducing production costs.

[0009] The present disclosure provides a method for preparing sterile concentrated tea extract with a low dissolved oxygen level, which comprises: a) Steeping tea leaves with water for 1 minute to 2 hours to obtain a steeped tea; b) Separating the tea leaves from the steeped tea, and cooling the steeped tea to room temperature, or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; c) Removing dissolved oxygen until the dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and d) Sterilizing the tea extract to obtain a final sterile concentrated tea extract with a low dissolved oxygen level; wherein the sterile concentrated tea extract with a low dissolved oxygen level has a Brix value of 0.3 to 3.3.

[0010] The present disclosure also provides a sterile concentrated tea extract with a low dissolved oxygen level prepared by the method of the present disclosure.

[0011] The present disclosure further provides a method for preparing ready-to-drink (RTD) tea beverages, which comprises: i) Mixing the sterile concentrated tea extract with a low dissolved oxygen level obtained by the method of the present disclosure or the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure with sterile deoxygenated water to obtain a tea beverage; and ii) Aseptically filling the tea beverage obtained in step i) into a container.

[0012] Wherein in step i), the dissolved oxygen concentration of the sterile deoxygenated water is 1.0 mg / L or lower, preferably 0.8 mg / L or lower, and more preferably 0.5 mg / L or lower.

[0013] The present disclosure also provides ready-to-drink tea beverages prepared by the method of the present disclosure.

[0014] The present disclosure also provides a drink, a beverage, or beverage product containing the sterile concentrated tea extract or the tea beverage prepared by the method of the present disclosure.

[0015] Compared to prior art, the present disclosure offers the following beneficial effects: By controlling the amount of dissolved oxygen in the concentrated tea extract, it is not necessary to add large amounts of antioxidants and there is no need for extensive nitrogen gas replacement and protection while it preserves the taste of the final product, thereby achieving a final product with a flavor close to freshly brewed tea, delaying quality degradation and reducing production costs.

[0016] From the detailed description below, other objectives, features, and advantages of the present disclosure will become apparent. However, it should be understood that while the detailed description and specific embodiments illustrate preferred implementation of the disclosure, they are provided only as examples. Various changes and improvements within the spirit and scope of the disclosure will become evident to those skilled in the art from the detailed description.DETAILED DESCRIPTION

[0017] The method for preparing sterile concentrated tea extract with a low dissolved oxygen level provided by the present disclosure comprises the following steps: a) Steeping tea leaves with water for 1 minute to 2 hours, preferably for 5 minutes to 1 hour, and more preferably for 10 minutes to 40 minutes, to obtain a steeped tea;b) Separating the tea leaves from the steeped tea, and either cooling the steeped tea to room temperature or maintaining it at a temperature of 5°C to 25°C, preferably 10°C to 20°C, and more preferably 13°C to 17°C, to obtain an initial tea extract; c) Removing dissolved oxygen until the dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower, preferably 3.0 mg / L or lower, and more preferably 1.0 mg / L or lower; and d) Sterilizing the tea extract to obtain a final sterile concentrated tea extract with a low dissolved oxygen level; wherein the sterile concentrated tea extract with a low dissolved oxygen level has a Brix value of 0.3 to 3.3.

[0018] The "dissolved oxygen" (DO) used here in the present disclosure is the oxygen concentration in an aqueous solution. The inventors found that by controlling the dissolved oxygen concentration in the initial tea extract and adjusting sterilization conditions accordingly for the dissolved oxygen level in the initial tea extract, the method simultaneously achieves the technical effects of preserving the taste of the final product, achieving a final product with flavor close to freshly brewed tea, delaying quality degradation, and reducing production costs.

[0019] The tea leaves used in the present disclosure can be commonly known varieties, preferably selected from the group consisting of green tea, oolong tea, yellow tea, black tea, white tea, dark tea, flower tea, and combinations thereof.

[0020] Preferably, besides tea leaves step a) may further comprise additional plant materials, such as plants with both medicinal and food uses; some examples are red dates, goji berries, hawthorn, longan, sesame, nuts (peanuts, walnuts, and the like), dried fruits (raisins, dried apples, dried orange peels, dried pears, lemon slices, and the like), flowers (roses, chrysanthemums, gardenias, locust flowers, osmanthus, honeysuckle and the like), yam, platy codon, licorice, malva nuts, ginseng, etc. These additional plant materials can enhance the flavor, taste, functionality, etc. of the final product.

[0021] Preferably, the weight-to-volume ratio of tea leaves to water in step a) is 10-200 g / L, preferably 20-150 g / L, and more preferably 30-70 g / L. The extraction duration and temperature depend on the type of tea leaves. It can be hot extraction in which extraction isperformed under conditions similar to making tea with boiling water, or it can be cold extraction in which the guideline is to have minimal damage to key components (such as tea polyphenols). The shape of the tea leaves in step a) can be the original shape of dry tea leaves or crushed (broken) tea leaves in which the particle size of the crushed tea leaves is in the range of 4-50 mesh (0.3 mm to 4 mm), more preferably, in the range of 10-30 mesh (0.5 mm to 2 mm). In step a), water is used to extract at 5°C to 35°C for 15-120 minutes, preferably 15-70 minutes or extract at 35°C to 100°C for 3-30 minutes. More preferably, extraction is performed at 20°C to 30°C for 15-50 minutes as this condition will deliver fresher flavors and higher productivity; preferably, extraction is performed at 40°C-98°C, and more preferably at 60°C to 95°C, as this condition will deliver richer flavors.

[0022] According to the present disclosure, various methods can be used to remove dissolved oxygen. Preferably, the removal of dissolved oxygen in step c) is to add 0.1-1.0 wt% of antioxidants based on the total weight of the initial tea extract to the initial tea extract and / or to treat the initial tea extract under a vacuum of below 0.8 bar; more preferably, the removal of dissolved oxygen in step c) is to add 0.1 -1.0 wt% of antioxidants based on the total weight of the initial tea extract to the initial tea extract alone; further preferably, the removal of dissolved oxygen in step c) is to add 0.1 -0.8 wt % of antioxidants based on the total weight of the initial tea extract to the initial tea extract alone and to treat the initial tea extract under a vacuum of below 0.5 bar. The added antioxidants may bring other flavors to the steeped tea, and the vacuum treatment at a negative pressure easily results in loss of aroma. The combination of the two can reduce the amount of antioxidants used and the loss of aroma due to the vacuum treatment under a negative pressure.

[0023] The "soluble solids content" or "Brix" mentioned in the present disclosure refers to the total soluble solids content in the liquid, including sugars, acids, vitamins, minerals, and the like. The Brix of the sterile concentrated tea extract with a low dissolved oxygen level obtained by the method of the present disclosure is 0.3 to 3.3. Preferably, the Brix of the sterile concentrated tea extract with a low dissolved oxygen level is 0.5 to 2.4, and more preferably 0.6 to 1.8.

[0024] In addition to controlling the dissolved oxygen in step c), preferably, the water used in step a) should have a dissolved oxygen concentration of less than 1.2 mg / L, preferably less than 1.0 mg / L, and more preferably less than 0.8 mg / L, and most preferably, the water used in step a) is deoxygenated water. More preferably, the water is "deoxygenated reverse osmosis (RO) water", that is, RO water obtained by a deoxygenating treatment or RO water will lower oxygen concentrations. Said "RO water (reverse osmosis water)" is deionized water prepared by reverse osmosis-ion exchange equipment; its preparation process may comprise: raw water — > multi-media filter — activated carbon filter — precision filter reverse osmosis equipment.

[0025] The extraction step in step a) can be carried out with stirring, wherein the stirring is conducted at a rate of 10-60 RPM, preferably 15-40 RPM, or more preferably 10-20 RPM, for a duration of 10 seconds to 30 minutes, preferably 30 seconds to 20 minutes, and more preferably 1 minute to 10 minutes. The stirring can be either continuous or intermittent.

[0026] The antioxidant used in step c) is selected from ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and combinations thereof. The amount of antioxidants added in step (c) is 0.2-0.6 wt%, preferably 0.25-0.35 wt% based on the total weight of the initial tea extract.

[0027] Preferably, before the treatment in step c), the dissolved oxygen concentration of the initial tea extract is from 5 mg / L to saturated dissolved oxygen concentration.

[0028] The present disclosure provides a sterile concentrated tea extract with a low dissolved oxygen level obtained using the method of the present disclosure. The sterile concentrated tea extract with a low dissolved oxygen level is a "tea concentrate," which is a steeped tea with a high content of soluble solids (Brix). When diluted with an appropriate amount of water, it produces a ready -to-drink (RTD) tea beverage. The term "N-times concentrate" mentioned in the present disclosure, such as "4-times concentrate," refers to one part by volume of concentrate is diluted with four parts by volume of water to produce an RTD beverage. Similarly, " 1-time concentrate," "2-times concentrate," "3-times concentrate," "5-times concentrate," and so on refer to concentrates diluted with 1 part, 2parts, 3 parts, 5 parts, or so on by volume of water to obtain an RTD beverage. The present disclosure preferably uses 2-5 times concentrates, more preferably 3-4 times concentrates.

[0029] The "ready-to-drink beverage" or "RTD beverage" mentioned in the present disclosure refers to a liquid beverage that can be directly consumed without the need for further addition of liquid. The present disclosure provides a method for preparing an RTD tea beverage, which comprises:1) mixing the sterile concentrated tea extract with a low dissolved oxygen level obtained using the method of the present disclosure or the sterile concentrated tea extract with a low dissolved oxygen level with sterile deoxygenated water, to obtain a tea beverage, and2) aseptically filling the tea beverage obtained in step 1).

[0030] Wherein in step 1), the dissolved oxygen concentration of the sterile deoxygenated water is 1.0 mg / L or lower, preferably 0.8 mg / L or lower, and more preferably 0.5 mg / L or lower.

[0031] The sterile concentrated tea extract with a low dissolved oxygen level and the sterile deoxygenated water can be filled into the final container either simultaneously or in batches to achieve mixing. The volume ratio of the sterile concentrated tea extract with a low dissolved oxygen level to the sterile deoxygenated water is 1 : 1 to 1 : 10, preferably 1 : 1 to 1 :6, and more preferably 1 :2 to 1 :4.

[0032] Preferably, the sterile concentrated tea extract with a low dissolved oxygen level is first filled into the final container, followed by the sterile deoxygenated water.

[0033] The sterile deoxygenated water in step 1) is degassed using one or more methods selected from vacuum degassing under a negative pressure, high-temperature degassing, antioxidant-assisted degassing, membrane separation deoxygenation, and nitrogen displacement deoxygenation. Preferably, the sterile deoxygenated water in step 1) is degassed under a vacuum and at an appropriate temperature (for example, degassed under a negative pressure of -0.6 bar to -0.8 bar and at a temperature of 65°C-80°C, preferably under a negative pressure of -0.7 bar and at a temperature of 70°C); high-temperaturedegassing is preferably performed at a temperature of 104°C-108°C, preferably 104°C; degassing by adding antioxidants is preferably adding 0.004%-0.02% of antioxidants, and more preferably, the ratio of the added antioxidants to the dissolved oxygen is 5.5 (based on the vitamin C amount): ! (based on the oxygen amount). Preferably, membrane separation deoxygenation uses polypropylene membranes or polytetrafluoroethylene membranes for deoxygenation. More preferably, deoxygenation-treated RO water is used to obtain RO water with lower dissolved oxygen concentrations. The "RO water (reverse osmosis water) is deionized water prepared by using reverse osmosis-ion exchange equipment; its preparation process can comprise: raw water —> multi-media filter activated carbon filter —> precision filter — reverse osmosis equipment.

[0034] Using the method of the present disclosure to produce tea beverages, the sterile concentrated tea extract with a low dissolved oxygen level and sterile deoxygenated water described in the present disclosure are prepared under different conditions. In this way, since the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure is a concentrated steeped tea with a limited amount of solvent, the dissolved oxygen content is inherently low, and it is possible to use a smaller amount of antioxidants to further reduce the dissolved oxygen in the concentrated steeped tea to a very low level. While the amount of antioxidants in the final product is reduced, it is still possible to ensure the reduction of tea polyphenol oxidation. Additionally, the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure can serve as an independent semi-finished product, allowing it to be stored and transported as needed. For example, during peak seasons of raw tea material production, a large quantity of the sterile concentrated tea extract with a low dissolved oxygen level can be prepared and stored, enabling continuous production during off-seasons. Furthermore, in the sterilization process, sterilizing the concentrated steeped tea, which has a smaller volume compared to the final product, under mild conditions saves more energy, improves productivity, and reduces production costs compared to sterilizing the final product, which has a larger volume, under mild conditions. The preferred sterilization method for sterilizing the concentrated tea extract with a low dissolved oxygen level of the present disclosure is ultra-high-temperature (UHT) instantaneous sterilization, with sterilization temperatures ranging from 98°C to 145°C and sterilization duration of 4 seconds to 60 seconds.

[0035] In addition, the separately treated sterile deoxygenated water does not pose concerns about component degradation since it does not contain sensitive active components. Therefore, more stringent conditions can be used for faster and more thorough sterilization. The mixing of the sterile concentrated tea extract with a low dissolved oxygen level and the sterile deoxygenated water according to the present disclosure can be carried out in an aseptic filling environment.

[0036] The present disclosure also provides a tea beverage obtained with the method of the present disclosure. The final tea beverage product of the present disclosure has a flavor close to freshly brewed tea, having the advantages of delayed quality degradation and lower production costs.

[0037] It should be noted that the "tea beverage" according to the present disclosure also encompasses a tea beverage product containing the sterile concentrated tea extract or a product derived from the sterile concentrated tea extract. An example of the tea beverage product is a diluted product of the sterile concentrated tea extract with an external source, such as sterile deoxygenated water, water, another liquid or beverage such as milk, juice, coffee, etc. The term "external source" used here in refers to any substance, material, or component added to a tea extract or a tea beverage that originates from outside the primary ingredient or base formulation of the tea extract or the tea beverage. For example, an external source can be any additional ingredient or component that is combined with the sterile concentrated tea extract to create the final tea beverage or beverage product.

[0038] The present disclosure also provides a non-RTD tea beverage. A "non-ready-to-drink (non-RTD) beverage" used herein refers to tea beverage product that requires preparation by the consumer before it is ready to be consumed. An example of the non-RTD tea beverage includes the sterile concentrated tea extract according to the present disclosure or a product derived from the sterile concentrated tea extract according to the present disclosure. For example, the non- RTD tea beverage may include a mixture of the sterile concentrated tea extract with one or more ingredient or additive from an external source different from the sterile concentrated tea extract. The non-ready-to-drink (non-RTD) beverage may be diluted by the consumer with water or another liquid or beverage before it is ready to be consumed.

[0039] The present disclosure also provides a drink, a beverage, or beverage product containing the sterile concentrated tea extract, the tea beverage prepared by the method of the present disclosure, or any intermediate product generated in the process of preparing the sterile concentrated tea extract or the tea beverage according to the present disclosure. In some embodiments, a beverage product includes the sterile concentrated tea extract according to the present disclosure. The beverage product may further include a functional component, a nutrient, an ingredient, or an additive from an external source (i.e., not from the sterile concentrated tea extract), such as antioxidants, dietary fibers, amino acids, proteins, fatty acids, vitamins, glucosamine, minerals, salts, carbohydrates, sweeteners, preservatives, hydration agents, probiotics, prebiotics, weight management agents, osteoporosis management agents, phytoestrogens, long chain primary aliphatic saturated alcohols, phytosterols, alcohol, among others. In some embodiments, the beverage product includes a sweetener from an external source. In some embodiments, the beverage product is free from a sweetener from an external source. The sweetener can be an artificial or synthetic sweetener, a natural sweetener, a natural high potency sweetener. In some embodiments, a beverage product includes the sterile concentrated tea extract or tea beverage according to the present disclosure and one or more additional beverages. The additional beverage may be a juice, a fruit juice, a coffee beverage, a milk beverage, a diary beverage, a plant protein beverage, a plant-based beverage, a sport drink, an energy drink, among others. For example, the beverage product may be a mixture of the tea beverage according to the present disclosure and a juice beverage. The beverage product may be RTD beverage product or a non-RTD beverage product. The beverage product may have a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.

[0040] The present disclosure also provides methods for making the beverage products. In one example, the method includes adding to the sterile concentrated tea extract an ingredient or additive from an external source different from the sterile concentrated tea extract. In another example, the method includes diluting the sterile concentrated tea extract with an external source.

[0041] The following specific examples further detail the objectives, structural features, and advantages of the present disclosure. These examples are provided solely for a better understanding of the disclosure and are not intended to limit its scope of protection.

[0042] Testing Methods Used in the Examples of the present disclosure:

[0043] 1) Determination of soluble solids content / Brix: A Rudolph refractometer JI 57 from USA is used, the sample to be tested is placed into a sample cell, the measurement is started, and the reading is recorded once stabilized.

[0044] 2) Determination of dissolved oxygen (DO) concentration: An HQ40d dissolved oxygen meter is used, a dissolved oxygen electrode is inserted into a liquid sample to be tested, and the reading is recorded once stabilized.

[0045] 3) Determination of aroma components: An instrument of solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) is used for aroma component analysis of a tea beverage:

[0046] SPME: A tea beverage sample of 5 g is placed into a 20 mL headspace vial. A DVB / CAR / PDMS fiber is used. The instrument is equipped with a Gerstel automatic sampling arm (MPS). The incubator temperature is set to 50°C, the equilibrium duration is set to 5 minutes, and the shaking frequency is set to 250 rpm. The fiber is allowed to adsorb the sample for 30 minutes. Analysis is performed at the sample injection port equipped with an SPME liner.

[0047] GC-MS conditions: Agilent GCMS (Model 7890A-5975C) equipped with the HP- INNOWAX capillary column is used. The carrier gas is He (purity > 99.999%). The sample is injected without splitting the flow; the temperature setting is a program temperature rise from an initial temperature of 45°C to the final temperature of 240°C, which is held for 5 minutes. The ion source is an El source, and the electron energy is 70 eV. The data is acquired by using the full-scan mode (Scan). The qualitative data for volatile substances are identified by comparing against the NIST 14. L standard library, and the analysis software is Agilent Chemstation software. The odor activity value or OAV is obtained by dividing the peak area from Chemstation software by the corresponding threshold value.

[0048] 4) Determination of tea polyphenols: A ferrous tartrate colorimetric method is used, and GB / T 21733-2008 is referenced.

[0049] 5) Determination of catechins: A Waters high-performance liquid chromatography (HPLC) system is used, and GB / T 8313-2018 is referenced.

[0050] 6) Determination of ascorbic acid: A HPLC method is used, and GB 5009.86-2016 is referenced.

[0051] 7) Sensory evaluation: Tea beverage samples are randomly coded with 3-digit numbers, and a panel of 10 professional tasters evaluate the samples according to tea sensory evaluation standards (Sensory Evaluation Techniques, 2nd Edition, Meilgaard Civille Carr. Scaling introduction).

[0052] Example 1

[0053] This example illustrates the preparation method of the sterile concentrated tea extract with a low dissolved oxygen level and tea beverage according to the present disclosure.

[0054] A total of 3.0 kg of Longjing green tea leaves was steeped in 108 L of RO water to extract at 30°C for 30 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C and centrifuged (centrifuge model LAPX404 SGP-31C, flow rate: 200 L / hr) and filtered through a 200-mesh sieve to obtain 107 L of a primary tea extract with a Brix of 0.64 (measured with the JI 57 refractometer described above).

[0055] The primary tea extract was diluted with RO water to a Brix of 0.60 to obtain a secondary tea concentrate, and its dissolved oxygen content was measured (which was 7.3 mg / L). The secondary tea concentrate was then heated to 65°C by using a plate heat exchanger, and the dissolved oxygen concentration was measured (which was 2.7 mg / L); Afterward, it was sterile in a high-temperature, high-pressure autoclave (model: GR85DA, 121 °C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extract with a low dissolved oxygen level (for 4x tea concentrate).

[0056] The sterile concentrated tea extract with a low dissolved oxygen level was mixed with 4 times its volume of sterile deoxygenated water (which had a dissolved oxygenconcentration close to 0 mg / L) in an aseptic filling environment to produce the tea beverage of the present disclosure (which had a dissolved oxygen concentration of 0.54 mg / L). Thus, the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure, when diluted with sterile deoxygenated water, becomes a ready-to-drink (RTD) tea beverage, wherein the sterile deoxygenated water did not introduce any dissolved oxygen into the final product.

[0057] Comparative Example 1

[0058] A total of 3.0 kg of Longjing green tea leaves was steeped in 108 L of RO water to extract at 30°C for 30 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C and centrifuged (centrifuge flow rate: 200 L / hr) and filtered (through a 200-mesh sieve) to obtain 107 L of a primary steeped tea extract with a Brix of 0.64 (measured using the JI 57 refractometer described above).

[0059] The primary steeped tea extract was diluted with RO water to become a steeped tea with a Brix of 0.15, and its dissolved oxygen concentration was measured (which was 8.5 mg / L). The steeped tea was heated to 65°C using a plate heat exchanger and then subjected to degassing under a vacuum at a negative pressure of -0.7 bar and then to sterilization in a high-temperature, high-pressure autoclave (model: GR85DA, 121 °C, 5 minutes), and then it was cooled to room temperature in a sealed environment to obtain an RTD tea beverage (which had a dissolved oxygen concentration of 1.8 mg / L) according to conventional technology.

[0060] Table 1 shows the differences in dissolved oxygen concentration (mg / L) between the sterile concentrated tea extract with a low dissolved oxygen level and RTD tea beverage obtained in Example 1 and the RTD tea beverage obtained in Comparative Example 1 :Table 1 : Dissolved Oxygen Concentration Test Results

[0061] From Table 1, it can be seen that the sterile concentrated tea extract with a low dissolved oxygen level (for 4x tea concentrate) in Example 1 does not require a vacuum degassing treatment. By simply heating to 65°C using a plate heat exchanger before sterilization, the dissolved oxygen concentration was reduced to 2.7 mg / L. After preparing the RTD tea beverage, the final product had a dissolved oxygen concentration of only 0.54 mg / L, which is significantly lower than the RTD tea beverage in Comparative Example 1 that underwent a vacuum degassing treatment (1.8 mg / L). The low dissolved oxygen content in the RTD tea beverage of the present disclosure ensures the product has stable quality over an extended storage period, and due to the vacuum degassing step being eliminated, the production costs are also reduced.

[0062] Additionally, the aroma of the sterile concentrated tea extract with a low dissolved oxygen level obtained in Example 1 and the RTD tea beverage obtained in Comparative Example 1 was tested. The results are shown in Table 2 below:Table 2: Test Results of Key Aroma Components

[0063] From Table 2, it can be seen that the sterile concentrated tea extract with a low dissolved oxygen level (for 4x tea concentrate) in Example 1 does not require vacuum degassing. Compared to the RTD tea beverage prepared using vacuum degassing in Comparative Example 1, the sterile concentrated tea extract with a low dissolved oxygen level in Example 1 contains significantly lower levels of unpleasant odors (such as sulfuric, green, dusty / earthy, and fatty odors). Additionally, the pleasant fruity and floral aromas were better preserved in the sterile concentrated tea extract with a low dissolved oxygen level of Example 1.

[0064] Example 2

[0065] This example illustrates that, after mixtures of the sterile concentrated tea extract with low dissolved oxygen of the present disclosure of different concentrations with the same amount of antioxidant (vitamin C) added were treated by UHT sterilization, there were differences between the final RTD tea beverage products both in the retention rate of VC (indirectly reflecting the dissolved oxygen content), the retention rate of active teacomponents (reflecting the tea quality), and the content of the unpleasant "rotten cabbage odor component dimethyl trisulfide (DMTS) and in the sensory evaluation results.

[0066] A total of 1.2 kg of steamed green tea leaves was steeped in 30 L of RO water to extract at 55°C for 20 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C and centrifuged (centrifuge flow rate: 200 L / hr) and filtered (through a 200-mesh sieve) to obtain 22 L of a primary steeped tea extract with a Brix value of 1.39 (measured with the J 157 refractometer described above).

[0067] The primary steeped tea extract was diluted with RO water to a Brix value of 0.55, 0.91, and 1.28, respectively obtaining three secondary tea concentrates. Vitamin C was added at a weight percentage of 0.30%. Then, the tea extracts were sterilized using a high- temperature autoclave (Model: GR85DA, 121 °C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 2-1, 2-2, and 2-3). The retention rates of vitamin C and active tea components (Epigallocatechin-3 -gallate (EGCG), catechins, and tea polyphenols) were tested after sterilization.

[0068] The sterile concentrated tea extracts with a low dissolved oxygen level of Examples 2-1, 2-2, and 2-3 were respectively mixed with 2 times, 4 times, and 6 times its volume of the sterile deoxygenated water (which had a dissolved oxygen concentration close to 0 mg / L) under aseptic filling conditions to obtain final RTD tea beverage products of Examples 2-1, 2-2, and 2-3.

[0069] Comparative Example 2

[0070] The primary steeped tea extract from Example 2 was diluted in a single step with RO water to prepare a final RTD tea beverage product with a Brix value of 0.18. Vitamin C was added at a weight percentage of 0.06%, followed by sterilization using a high- temperature autoclave (Model: GR85DA, 121°C, 5 minutes). The product was cooled to room temperature in a sealed environment to obtain the final of RTD tea beverage product of Comparative Example 2. The retention rates of vitamin C and active tea components (EGCG, catechins, and tea polyphenols) were tested after sterilization.

[0071] The differences in the content of the unpleasant "rotten cabbage" odor component dimethyl trisulfide (DMTS) and sensory evaluation between the final RTD tea beverage products from Examples 2-1, 2-2, 2-3, and Comparative Example 2 were tested.

[0072] Table 3 presents the differences in various aspects between the sterile concentrated tea extracts with a low dissolved oxygen level and final RTD tea beverage products of Examples 2-1, 2-2, and 2-3, and the final RTD tea beverage product of Comparative Example 2.Table 3

[0073] From Table 3, it can be seen that, for steeped tea of different volume times of concentration, adding the same amount of VC results in differences in VC and catechin retention rates after UHT sterilization. Based on the above experimental results, considering the flavor of the final product comprehensively, Example 2-2, with 4x tea concentrate and 0.30% VC added, showed the best flavor retention in the sterile final product and the highest retention rates of VC and catechins after sterilization. It can also be seen that the tea beverages prepared by separately sterilizing the concentrated steeped tea and the diluting water in Examples 2-1, 2-2, and 2-3 had significantly better quality thanthe tea beverage prepared by one-step dilution followed by sterilization in Comparative Example 2.

[0074] Example 3

[0075] This example illustrates that, after mixtures of the sterile concentrated tea extract with low dissolved oxygen of the present disclosure of the same concentration with the different amounts of the antioxidant (vitamin C) added were treated by UHT sterilization, there were differences between the final RTD tea beverage products both in the retention rate of VC (indirectly reflecting the dissolved oxygen content), the retention rate of active tea components (reflecting the tea quality), and the content of the unpleasant "rotten cabbage" odor component dimethyl trisulfide (DMTS) and in the sensory evaluation results.

[0076] A total of 1.2 kg of steamed green tea leaves was steeped in 30 L of RO water to extract at 55°C for 20 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C and centrifuged (centrifuge flow rate: 200 L / hr) and filtered (200-mesh sieve) to obtain 22 L of a primary steeped tea extract with a Brix value of 1.39 (measured with the JI 57 refractometer described above).

[0077] The primary steeped tea extract was diluted with RO water to a Brix value of 0.91 to obtain a secondary tea concentrate. Vitamin C was added at weight percentages of 0.30%, 0.45%, and 0.15%, respectively. Then the tea concentrates were sterilized using a high- temperature autoclave (Model: GR85DA, 121 °C for 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 3-1, 3-2, and 3-3). The retention rates of vitamin C and active tea components (EGCG, catechins, and tea polyphenols) were tested after sterilization.

[0078] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 3-1, 3-2, and 3-3 were mixed with 4 times its volume of sterile deoxygenated water (which had a dissolved oxygen concentration close to 0 mg / L) under sterile filling conditions to obtain the final RTD tea beverage products of Examples 3-1, 3-2, and 3-3.

[0079] The differences in the content of the unpleasant "rotten cabbage" odor component dimethyl trisulfide (DMTS) and sensory evaluation results between the final RTD tea beverage products from Examples 3-1, 3-2, 3-3, and Comparative Example 2 were tested.

[0080] Table 4 shows the differences in various aspects between the sterile concentrated tea extracts with a low dissolved oxygen level and the final tea beverage products of Examples 3-1, 3-2, and 3-3, and the final RTD tea beverage product of Comparative Example 2.Table 4

[0081] From Table 4, it can be seen that, after adding different amounts of VC (vitamin C) to the 4 times tea concentrate, followed by UHT sterilization, there were differences in the retention rates of VC and catechins. Based on the above experimental results and under the premise of comprehensively considering the flavor of the final product, the 4 times tea concentrate of Example 3-1, with 0.30% VC added, achieved the best flavor retention after sterilization and the best retention rates of VC and catechins after sterilization in the final products. It can also be seen that the quality of the tea beverages prepared by separately sterilizing the concentrated steeped tea and the diluting water in Examples 3-1, 3-2, and 3-3 was significantly better than the quality of the tea beverages prepared in Comparative Example 2, wherein a one-step dilution and subsequent sterilization were performed.

[0082] Table 5 shows the impact of different heating temperatures before UHT sterilization on the dissolved oxygen content in the concentrated steeped tea of the sterile concentrated tea extract with a low dissolved oxygen level and the final tea beverage product of Example 3-1 and in the concentrated steeped tea of the final RTD tea beverage product of Comparative Example 2.Table 5

[0083] From Table 5, it can be seen that, compared with Comparative Example 3, which uses the existing technology of one-step dilution to prepare the final RTD product, the present disclosure adopts a technical route in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared, and then it is mixed with sterile deoxygenated water (which had a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment during the preparation process of the final tea beverage product. As a result, the amount of oxygen redissolved into the semi-finished product during the heating treatment process is lower, and the dissolved oxygen content in the final tea beverage product of the present disclosure is significantly reduced. Moreover, as the heating treatment temperature before UHT sterilization increases, the dissolved oxygen content decreases accordingly.

[0084] Example 4

[0085] This example illustrates the effects of different concentrations of steeped tea, the same amount of antioxidant (vitamin C), and various heating temperatures on the dissolvedoxygen content of the sterile concentrated tea extract with a low dissolved oxygen of the present disclosure.

[0086] A total of 1.2 kg of steamed green tea leaves was steeped in 22 L of 25°C deoxygenated RO water (which had a dissolved oxygen concentration of: 1.83 mg / L) to extract for 20 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C and centrifuged (centrifuge flow rate: 200 L / hr) and filtered (through a 200-mesh sieve) to obtain 16 L of a primary steeped tea extract with a Brix of 1.43 (measured using the JI 57 refractometer described above).

[0087] The primary steeped tea extract was diluted with deoxygenated RO water (dissolved oxygen concentration: 1.83 mg / L) to obtain a secondary tea concentrates with Brix values of 0.78 (for 3x tea concentrate), 0.98 (for 4x tea concentrate), and 1.17 (for 5x tea concentrate) respectively. Vitamin C was respectively added at a weight percentage of 0.30%. After letting them stand at room temperature for 30 minutes, the dissolved oxygen content was measured for the first time. The tea concentrate was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. Subsequently, the tea concentrate was sterilized in a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and then cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 4-1, 4-2, and 4-3).

[0088] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 4-1, 4-2, and 4-3 were mixed, under sterile filling conditions, with respectively 3 times, 4 times and 5 times its volume of sterile deoxygenated water (which had a dissolved oxygen concentration close to 0) to obtain the final RTD tea beverage products of Examples 4-1, 4-2, and 4-3.

[0089] Comparative Example 3

[0090] The primary steeped tea extract from Example 4 was diluted in one step with RO water to prepare a final RTD tea beverage product with a Brix of 0.20. Vitamin C was added at a weight percentage of 0.06%. After letting it stand at room temperature for 30minutes, the dissolved oxygen content was measured for the first time. The steeped tea was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. Subsequently, the steeped tea was sterilized in a high- temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the final RTD tea beverage product of Comparative Example 3.

[0091] Table 6 shows the differences in dissolved oxygen content between the aseptic low- dissolved oxygen concentrated tea extracts (Examples 4-1, 4-2, and 4-3), their corresponding RTD tea beverage final products, and the RTD tea beverage final product of Comparative Example 3.

[0092] From Table 6, it can be seen that, compared with the final RTD product of Comparative Example 3, which was prepared by one-step dilution of the prior art, the present disclosure, by adopting a technical route of first preparing a sterile concentrated tea extract with a low dissolved oxygen level and then mixing it with sterile deoxygenated water (which had a dissolved oxygen concentration close to 0 mg / L) under sterile filling conditions during the process of preparing the final tea beverage product, significantly reduces the amount of oxygen redissolved into the semi-finished product during the heating process. Furthermore, the dissolved oxygen content in the final tea beverage product of the present disclosure is significantly reduced.

[0093] Example 5

[0094] This example is used to illustrate the effect of the same concentration of tea extract and different amounts of antioxidant (vitamin C) on the dissolved oxygen content of the sterile, low-dissolved oxygen concentrated tea extract of the present disclosure.

[0095] A total of 1.2 kg of steamed green tea leaves was steeped in 22 L of deoxygenated RO water (which had a dissolved oxygen concentration of: 1.83 mg / L) of 25°C to extract for 20 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the tea extract was cooled to 15°C, centrifuged (centrifuge flow rate: 200 L / hr), and filtered (200-mesh sieve) to obtain 16 L of primary steeped tea extract with a Brix value of 1.43 (measured using the JI 57 refractometer described above).

[0096] The primary steeped tea extract was diluted with deoxygenated RO water (dissolved oxygen concentration: 1.83 mg / L) to obtain a secondary tea concentrate with a Brix value of 0.98 (for 4 times tea concentrate). Vitamin C was added at weight percentages of 0.24%, 0.30%, and 0.36%, respectively. The tea concentrate was allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The tea concentrate was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The tea concentrate was sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 5-1, 5-2, and 5-3).

[0097] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 5-1, 5-2, and 5-3 were each mixed with four times their volume of sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment to obtain the final RTD tea beverage products of Examples 5-1, 5-2, and 5-3 of the present disclosure.

[0098] Table 7 shows the differences in the dissolved oxygen content between the sterile concentrated tea extracts with a low dissolved oxygen level and the final RTD tea beverageproducts of Examples 5-1, 5-2, and 5-3 and the final RTD tea beverage product of Comparative Example 3.Table 7

[0099] From Table 7, it can be seen that, under the condition of the same concentrated tea extract concentration, the dissolved oxygen content is negatively correlated with the amount of vitamin C added. Additionally, it is evident that, compared to Comparative Example 3, where the final RTD product is prepared by one-step dilution of the prior art, the present disclosure adopts a process in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared and then mixed with sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment. This technical approach results in significantly less oxygen being redissolved into the semi-finished product during the heating process. Consequently, the dissolved oxygen content of the final tea beverage product of the present disclosure is notably reduced.

[0100] Example 6

[0101] This example illustrates the method of preparing the sterile concentrated tea extract with a low dissolved oxygen level and tea beverage of the present disclosure by using jasmine tea as the raw material. It also examines the effects of different concentrations of tea extract, the same amount of antioxidant (vitamin C), and different heating temperatureson the dissolved oxygen content of the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure.

[0102] A total of 1.0 kg of jasmine tea leaves was steeped in 20 L of RO water of 25°C to extract for 18 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the tea extract was cooled to 15°C. The cooled tea extract was centrifuged (centrifuge flow rate: 200 L / hr) and filtered (200-mesh sieve) to obtain 15 L of primary steeped tea extract with a Brix value of 1.72, measured by using the aforementioned JI 57 refractometer.

[0103] The primary steeped tea extract was diluted with RO water to obtain secondary tea concentrate with Brix values of 0.69 (for 3 times tea concentrate), 0.86 (for 4 times tea concentrate), and 1.03 (for 5 times tea concentrate), respectively. Vitamin C was respectively added at a weight percentage of 0.30% to each tea concentrate. The tea concentrates were allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The tea concentrates were then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The tea concentrates were sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 6-1, 6-2, and 6-3).

[0104] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 6-1, 6-2, and 6-3 were then respectively mixed with 3 times, 4 times, and 5 times their volume of sterile deoxygenated water (dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment to obtain the final RTD tea beverage products of Examples 6-1, 6-2, and 6-3 of the present disclosure.

[0105] Comparative Example 4

[0106] The primary steeped tea extract from Example 6 was diluted in one step with RO water to obtain a final RTD tea beverage product with a Brix value of 0.20. Vitamin C was added at a weight percentage of 0.06%. The steeped tea was allowed to stand at roomtemperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The steeped tea was then heated to 65°C, and the dissolved oxygen content was measured for the second time. The steeped tea was sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the final RTD tea beverage product of Comparative Example 4.

[0107] Table 8 shows the differences in dissolved oxygen content between the sterile concentrated tea extracts with a low dissolved oxygen level and the final RTD tea beverage products of Examples 6-1, 6-2, and 6-3 and the final RTD tea beverage product of Comparative Example 4.Table 8

[0108] From Table 8, it can be seen that, with jasmine tea as the raw material, compared to Comparative Example 4, where the RTD final product is prepared by one-step dilution of the prior art, the present disclosure adopts a process in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared and then mixed with sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment. This technical approach results in significantly less oxygen being redissolved into the semi-finished product during the heating process. Consequently, the dissolved oxygen content of the final tea beverage product of the present disclosure is significantly reduced.

[0109] Example 7

[0110] This example illustrates the method for preparing the sterile concentrated tea extract with a low dissolved oxygen level and tea beverage of the present disclosure using jasmine tea as the raw material. It also demonstrates the effect of different amounts of the antioxidant (vitamin C) and steeped tea of the same tea concentration on the dissolved oxygen content of the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure.[OHl] A total of 1.0 kg of jasmine tea leaves was steeped in 20 L of RO water of 25°C to extract for 18 minutes with stirring at a speed of 20 RPM. After the tea leaves were removed, the steeped tea was cooled to 15°C. The cooled steeped tea was centrifuged (centrifuge flow rate: 200 L / hr) and filtered (200-mesh sieve) to obtain 15 L of a primary steeped tea extract with a Brix value of 1.72, measured using the aforementioned JI 57 refractometer.

[0112] The primary steeped tea extract was diluted with RO water to obtain a secondary tea concentrate with a Brix value of 0.86 (for 4 times tea concentrate), to which vitamin C was added at weight percentages of 0.24%, 0.30%, and 0.36%, respectively. The tea concentrate was allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The tea concentrate was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The tea concentrate was sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 7-1, 7-2, and 7-3).

[0113] The sterile concentrated tea extracts with a low dissolved oxygen level of Examples 7-1, 7-2, and 7-3 were then respectively mixed with 3 times, 4 times, and 5 times their volume of sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment to obtain the final RTD tea beverage products of Examples 7-1, 7-2, and 7-3 of the present disclosure.

[0114] Table 9 shows the differences in dissolved oxygen content between the sterile concentrated tea extracts with a low dissolved oxygen level and final RTD tea beverage products of Examples 7-1, 7-2, and 7-3, and the final RTD tea beverage product of Comparative Example 4.Table 9

[0115] From Table 9, it can be seen that, with jasmine flower tea as the raw material, under the condition of the same concentration of steeped tea, the dissolved oxygen content is negatively correlated with the amount of vitamin C added. Additionally, it is evident that, compared to Comparative Example 4, where the final RTD product is prepared by one-step dilution of the prior art, the present disclosure adopts a process in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared and then mixed with sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment. This technical approach results in significantly less oxygen being redissolved into the semi-finished product during the heating process. Consequently, the dissolved oxygen content of the tea beverage final product in this disclosure is significantly reduced.

[0116] Example 8

[0117] This example illustrates the method for preparing the sterile concentrated tea extract with a low dissolved oxygen level and tea beverage of the present disclosure using oolong tea (Da Hong Pao) as the raw material. It also demonstrates the effect of different amountsof the antioxidant (vitamin C) and steeped tea of the same concentration on the dissolved oxygen content of the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure.

[0118] A total of 2.0 kg of Da Hong Pao tea leaves was steeped in 30 L of RO water of 80°C to extract for 10 minutes. After the tea leaves were removed, the steeped tea was cooled to 15°C. The cooled steeped tea was centrifuged (centrifuge flow rate: 200 L / hr) and filtered (200-mesh sieve) to obtain 26 L of a primary steeped tea extract with a Brix value of 1.19, measured using the aforementioned JI 57 refractometer.

[0119] The primary steeped tea extract was diluted with RO water to obtain a secondary tea concentrate with a Brix value of 0.75 (for 4 times tea concentrate) to which vitamin C was added at weight percentages of 0.24%, 0.30%, and 0.36%, respectively. The tea concentrate was allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The tea concentrate was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The tea concentrate was sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen of the present disclosure (Examples 8-1, 8-2, and 8-3).

[0120] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 8-1, 8-2, and 8-3 were each mixed with four times their volume of sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment to obtain the final RTD tea beverage products of Examples 8-1, 8-2, and 8-3 of the present disclosure.

[0121] Comparative Example 5

[0122] The primary steeped tea extract from Example 8 was diluted in one step with RO water to obtain a final RTD tea beverage product with a Brix value of 0.15, to which vitamin C was added at a weight percentage of 0.06%. The beverage was allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured forthe first time. The beverage was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The beverage was sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the final RTD tea beverage product of Comparative Example 5.

[0123] Table 10 shows the differences in dissolved oxygen content between the sterile concentrated tea extracts with a low dissolved oxygen level and the final RTD tea beverage products of Examples 8-1, 8-2, and 8-3, and the final RTD tea beverage product of Comparative Example 5.Table 10

[0124] From Table 10, it can be seen that, with oolong tea as the raw material, under the condition of the same concentration of tea extract, the dissolved oxygen content is negatively correlated with the amount of vitamin C added. Additionally, it is evident that, compared to Comparative Example 5, where the final RTD product is prepared by one-step dilution of the prior art, the present disclosure adopts a process in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared and then mixed with sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment. This technical approach results in significantly less oxygenbeing redissolved into the semi-finished product during the heating process. Consequently, the dissolved oxygen content of the tea beverage final product in this disclosure is significantly reduced.

[0125] Example 9

[0126] This example illustrates the method for preparing the sterile concentrated tea extract with a low dissolved oxygen level and tea beverage of the present disclosure using black tea as the raw material. It also examines the effects of different concentrations of tea extract, the same amount of the antioxidant (vitamin C), and different heating temperatures on the dissolved oxygen content of the sterile concentrated tea extract with a low dissolved oxygen level of the present disclosure.

[0127] A total 2.0 kg of black tea leaves was steeped in 30 L of RO water of 70°C to extract for 5 minutes. After the tea leaves were removed, the steeped tea was cooled to 15°C and then centrifuged (centrifuge flow rate: 200 L / hr) and filtered (200-mesh sieve) to obtain 27 L of a primary steeped tea extract with a Brix value of 1.72, measured using the aforementioned JI 57 refractometer.

[0128] The primary steeped tea extract was diluted with RO water to obtain secondary steeped tea concentrates with Brix values of 0.69 (for 3 times tea concentrate), 0.86 (for 4 times tea concentrate), and 1.03 (for 5 times tea concentrate), respectively, to each of which vitamin C was added at a weight percentage of 0.30%. The tea concentrates were allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The tea concentrates were then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. Then they were sterilized using a high-temperature autoclave (model: GR85DA, 121°C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the sterile concentrated tea extracts with a low dissolved oxygen level of the present disclosure (Examples 9-1, 9-2, and 9-3).

[0129] The sterile concentrated tea extracts with a low dissolved oxygen level from Examples 9-1, 9-2, and 9-3 were each mixed with 3 times, 4 times, and 5 times theirvolume of sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment to obtain the final RTD tea beverage products of Examples 9-1, 9-2, and 9-3 of the present disclosure.

[0130] Comparative Example 6

[0131] The primary steeped tea extract from Example 9 was diluted in one step with RO water to obtain a final RTD tea beverage product with a Brix value of 0.17, to which vitamin C was added at a weight percentage of 0.06%. The beverage was allowed to stand at room temperature for 30 minutes, and the dissolved oxygen content was measured for the first time. The beverage was then heated to 65°C using a plate heat exchanger, and the dissolved oxygen content was measured for the second time. The beverage was sterilized using a high-temperature autoclave (model: GR85DA, 121 °C, 5 minutes) and cooled to room temperature in a sealed environment to obtain the final RTD tea beverage product of Comparative Example 6.

[0132] Table 11 shows the differences in dissolved oxygen content between the sterile concentrated tea extracts with a low dissolved oxygen level and the RTD tea beverage final products of Examples 9-1, 9-2, and 9-3, and the final RTD tea beverage product of Comparative Example 6.Table 11

[0133] From Table 11, it can be seen that, with black tea as the raw material, compared to Comparative Example 6, where the final RTD product is prepared by one-step dilution ofthe prior art, the present disclosure adopts a process in which a sterile concentrated tea extract with a low dissolved oxygen level is first prepared and then mixed with sterile deoxygenated water (with a dissolved oxygen concentration close to 0 mg / L) in a sterile filling environment. This technical approach results in significantly less oxygen being redissolved into the semi-finished product during the heating process. Consequently, the dissolved oxygen content of the tea beverage final product in this disclosure is significantly reduced.

[0134] The present disclosure that is illustratively disclosed herein can be implemented appropriately even in the absence of any elements not explicitly disclosed herein. However, it is apparent to those skilled in the art that many modifications, variations, improvements, other uses, and applications of this method are possible. Modifications, variations, improvements, other uses, and applications that do not deviate from the spirit and scope of the present disclosure are also considered to be covered by the disclosure, which is defined solely by the appended claims.

[0135] The following numbered clauses define further embodiments of the present disclosure:NUMBERED CLAUSES1. A method comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3.2. The method of clause 1 , wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.3. The method of any one of clauses 1 and 2, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.4. The method of any one of clauses 1 to 3, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.5. The method of any one of clauses 1 to 4, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.6. The method of any one of clauses 1 to 4, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.7. The method of any one of clauses 1 to 6, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.8. The method of clause 7, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.9. The method of any one of clauses 7 and 8, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on the total weight of the initial tea extract.10. The method of any one of clauses 1 to 9, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.11. The method of any one of clauses 1 to 10, wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.12. The method of any one of clauses 1 to 11, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.13. The method of any one of clauses 1 to 12, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.14. The method of any one of clauses 1 to 13, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.15. The method of any one of clauses 1 to 14, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.16. The method of any one of clauses 1 to 15, further comprising: mixing the sterile concentrated tea extract with sterile deoxygenated water to obtain a mixture, wherein the sterile deoxygenated water has a dissolved oxygen concentration of 1.0 mg / L or lower, and aseptically filling a container with the mixture to obtain a tea beverage.17. The method of clause 16, wherein the sterile concentrated tea extract and the sterile deoxygenated water are simultaneously added to the container and mixed in the container.18. The method of clause 16, wherein the sterile concentrated tea extract is added to the container, and then the sterile deoxygenated water is subsequently added to the container.19. The method of any one of clauses 16 to 18, wherein a volume ratio of the sterile concentrated tea extract to the sterile deoxygenated water is 1 : 1 to 1 : 10.20. The method of any one of clauses 16 to 19, wherein the sterile deoxygenated water is prepared by a deoxygenation process selected from the group consisting of: vacuum degassing, high-temperature degassing, antioxidant treatment, membrane separation, nitrogen displacement, and any combinations thereof.21. The sterile concentrated tea extract prepared by the method of any one of clauses 1 to 15.22. The tea beverage prepared by the method of any one of clauses 16 to 20.23. A tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.24. A tea beverage, comprising a tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.25. The tea beverage of clause 24, wherein the tea extract is the sterile concentrated tea extract prepared by the method of any one of clauses 1 to 15.26. The tea beverage of clauses 24 or 25, further comprising an additive from an external source different from the tea extract, wherein the additive comprises one or more selected from antioxidant, dietary fiber, amino acid, protein, fatty acid, vitamin, glucosamine, mineral, salt, carbohydrate, sweetener, preservative, hydration agent, probiotics, prebiotics, weight management agent, osteoporosis management agent, phytoestrogen, long chain primary aliphatic saturated alcohol, phytosterol, and alcohol.27. The tea beverage of any one of clauses 24-26, further comprising water, wherein the tea extract is diluted by the water.28. The tea beverage of clause 27, wherein the water is deoxygenated water having a dissolved oxygen concentration of 1.0 mg / L or lower.29. The tea beverage of any one of clauses 24-28, wherein the tea beverage is a ready- to-drink (RTD) tea beverage.30. The tea beverage of clauses 24 to 28, wherein the tea beverage is a non-ready-to- drink (non-RTD) tea beverage.31. A beverage product, comprising a tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.32. The beverage product of clause 31, further comprising a beverage.33. The beverage product of clause 32, wherein the beverage is selected from a juice, a fruit juice, a coffee beverage, a milk beverage, a diary beverage, a plant protein beverage, a plantbased beverage, a sport drink, and an energy drink.34. The beverage product of any one of clauses 31-33, wherein the beverage product is a ready-to-drink (RTD) beverage.35. The tea beverage of any one of clauses 31-33, wherein the beverage product is a non-ready-to-drink (non-RTD) beverage.36. A beverage product, comprising a tea extract and an external source, wherein the beverage product has a dissolved oxygen level of 1.0 mg / L or lower and a Brix value of 1 or lower.37. The beverage product of clause 36, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.38. The beverage product of clauses 36 or 37, wherein the external source comprises water, wherein the tea extract is diluted by the water.39. The beverage product of clause 38, wherein the water is deoxygenated water having a dissolved oxygen concentration of 1.0 mg / L or lower.40. The beverage product of any one of clauses 36 to 39, wherein the external source comprises an additive from an external source different from the tea extract, wherein the additive comprises one or more selected from antioxidant, dietary fiber, amino acid, protein, fatty acid, vitamin, glucosamine, mineral, salt, carbohydrate, sweetener, preservative, hydration agent, probiotics, prebiotics, weight management agent, osteoporosis management agent, phytoestrogen, long chain primary aliphatic saturated alcohol, phytosterol, and alcohol.41. The beverage product of any one of clauses 36 to 40, wherein the external source comprises a juice, a fruit juice, a coffee beverage, a milk beverage, a diary beverage, a plant protein beverage, a plant-based beverage, a sport drink, and an energy drink.42. The beverage product of any one of clauses 36-41, wherein the beverage product is a ready-to-drink (RTD) beverage product.43. The beverage product of clauses 36 to 42, wherein the tea beverage is a non-ready- to-drink (non-RTD) beverage product.44. A sterile concentrated tea extract made by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3.45. The sterile concentrated tea extract of clause 44, wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.46. The sterile concentrated tea extract of any one of clauses 44 and 45, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.47. The sterile concentrated tea extract of any one of clauses 44 to 46, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.48. The sterile concentrated tea extract of any one of clauses 44 to 47, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.49. The sterile concentrated tea extract of any one of clauses 44 to 47, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.50. The sterile concentrated tea extract of any one of clauses 44 to 49, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.51 . The sterile concentrated tea extract of clause 50, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.52. The sterile concentrated tea extract of any one of clauses 50 and 51, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on the total weight of the initial tea extract.53. The sterile concentrated tea extract of any one of clauses 44 to 52, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.54. The sterile concentrated tea extract of any one of clauses 44 to 53, wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.55. The sterile concentrated tea extract of any one of clauses 44 to 54, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.56. The sterile concentrated tea extract of any one of clauses 44 to 55, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.57. The sterile concentrated tea extract of any one of clauses 44 to 56, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.58. The sterile concentrated tea extract of any one of clauses 44 to 57, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.59. A tea beverage made by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea;cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3; mixing the sterile concentrated tea extract with sterile deoxygenated water to obtain a mixture, wherein the sterile deoxygenated water has a dissolved oxygen concentration of 1.0 mg / L or lower; and aseptically filling a container with the mixture to obtain the tea beverage, wherein the tea beverage is a ready to drink (RTD) tea beverage.60. The tea beverage of clause 59, wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.61. The tea beverage of any one of clauses 59 and 60, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.62. The tea beverage of any one of clauses 59 to 61, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.63. The tea beverage of any one of clauses 59 to 62, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.64. The tea beverage of any one of clauses 59 to 62, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.65. The tea beverage of any one of clauses 59 to 63, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.66. The tea beverage of clause 65, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.67. The tea beverage of any one of clauses 65 and 66, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on the total weight of the initial tea extract.68. The tea beverage of any one of clauses 59 to 67, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.69. The tea beverage of any one of clauses 59 to 68, wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.70. The tea beverage of any one of clauses 59 to 69, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.71. The tea beverage of any one of clauses 59 to 70, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.72. The tea beverage of any one of clauses 59 to 71, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.73. The tea beverage of any one of clauses 59 to 72, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.74. The tea beverage of any one of clauses 59 to 73, wherein the sterile concentrated tea extract and the sterile deoxygenated water are simultaneously added to the container and mixed in the container.75. The tea beverage of any one of clauses 59 to 74, wherein the sterile concentrated tea extract is added to the container, and then the sterile deoxygenated water is subsequently added to the container.76. The tea beverage of any one of clauses 59 to 75, wherein a volume ratio of the sterile concentrated tea extract to the sterile deoxygenated water is 1: 1 to 1 :10.77. The tea beverage of any one of clauses 59 to 76, wherein the sterile deoxygenated water is prepared by a deoxygenation process selected from the group consisting of: vacuum degassing, high-temperature degassing, antioxidant treatment, membrane separation, nitrogen displacement, and any combinations thereof.78. The tea beverage of any one of clauses 59 to 77, wherein the tea beverage has a dissolved oxygen level of 1.0 mg / L or lower and a Brix value of 1 or lower.

Claims

WHAT IS CLAIMED IS:

1. A method comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3.

2. The method of claim 1, wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.

3. The method of claim 1, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.

4. The method of claim 1, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.

5. The method of claim 1, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.

6. The method of claim 1, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.

7. The method of claim 1, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.

8. The method of claim 7, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.

9. The method of claim 7, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on a total weight of the initial tea extract.

10. The method of claim 1, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.

11. The method of claim 1 , wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.

12. The method of claim 1, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.

13. The method of claim 1, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.

14. The method of claim 1, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.

15. The method of claim 1, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.

16. The method of claim 1, further comprising: mixing the sterile concentrated tea extract with sterile deoxygenated water to obtain a mixture, wherein the sterile deoxygenated water has a dissolved oxygen concentration of 1.0 mg / L or lower, and aseptically filling a container with the mixture to obtain a tea beverage.

17. The method of claim 16, wherein the sterile concentrated tea extract and the sterile deoxygenated water are simultaneously added to the container and mixed in the container.

18. The method of claim 16, wherein the sterile concentrated tea extract is added to the container, and then the sterile deoxygenated water is subsequently added to the container.

19. The method of claim 16, wherein a volume ratio of the sterile concentrated tea extract to the sterile deoxygenated water is 1 : 1 to 1 : 10.

20. The method of claim 16, wherein the sterile deoxygenated water is prepared by a deoxygenation process selected from the group consisting of: vacuum degassing, high-temperature degassing, antioxidant treatment, membrane separation, nitrogen displacement, and any combinations thereof.

21. The sterile concentrated tea extract prepared by the method of claim 1.

22. The tea beverage prepared by the method of claim 16.

23. A tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.

24. A tea beverage comprising a tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.

25. The tea beverage of claim 24, wherein the tea extract is a sterile concentrated tea extract prepared by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain the concentrated tea extract.

26. The tea beverage of claim 24, further comprising an additive from an external source different from the tea extract, wherein the additive comprises one or more selected from antioxidant, dietary fiber, amino acid, protein, fatty acid, vitamin, glucosamine, mineral, salt, carbohydrate, sweetener, preservative, hydration agent, probiotics, prebiotics, weight management agent, osteoporosis management agent, phytoestrogen, long chain primary aliphatic saturated alcohol, phytosterol, and alcohol.

27. The tea beverage of claim 24, further comprising water, wherein the tea extract is diluted by the water.

28. The tea beverage of claim 27, wherein the water is deoxygenated water having a dissolved oxygen concentration of 1.0 mg / L or lower.

29. The tea beverage of claim 24, wherein the tea beverage is a ready-to-drink (RTD) tea beverage.

30. The tea beverage of claim 24, wherein the tea beverage is a non-ready-to-drink (non-RTD) tea beverage.

31. A beverage product, comprising a tea extract, wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.

32. The beverage product of claim 31, wherein the tea extract is a sterile concentrated tea extract prepared by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain the concentrated tea extract.

33. The beverage product of claim 31, further comprising a beverage, wherein the beverage is selected from a juice, a fruit juice, a coffee beverage, a milk beverage, a diary beverage, a plant protein beverage, a plant-based beverage, a sport drink, and an energy drink.

34. The beverage product of claim 31 , wherein the beverage product is a ready -to-drink (RTD) beverage.

35. The tea beverage of claim 31, wherein the beverage product is a non-ready-to-drink (non-RTD) beverage.

36. A beverage product, comprising a tea extract and an external source, wherein the beverage product has a dissolved oxygen level of 1.0 mg / L or lower and a Brix value of 1 or lower.

37. The beverage product of claim 36, wherein the tea extract is a sterile concentrated tea extract prepared by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain the concentrated tea extract wherein the tea extract has a dissolved oxygen level of 5.0 mg / L or lower and a Brix value from 0.3 to 3.3.

38. The beverage product of claim 36, wherein the external source comprises water, wherein the tea extract is diluted by the water.

39. The beverage product of claim 38, wherein the water is deoxygenated water having a dissolved oxygen concentration of 1.0 mg / L or lower.

40. The beverage product of claim 36, wherein the external source comprises an additive from an external source different from the tea extract, wherein the additive comprises one or more selected from antioxidant, dietary fiber, amino acid, protein, fatty acid, vitamin,glucosamine, mineral, salt, carbohydrate, sweetener, preservative, hydration agent, probiotics, prebiotics, weight management agent, osteoporosis management agent, phytoestrogen, long chain primary aliphatic saturated alcohol, phytosterol, and alcohol.

41. The beverage product of claim 36, wherein the external source comprises a juice, a fruit juice, a coffee beverage, a milk beverage, a diary beverage, a plant protein beverage, a plantbased beverage, a sport drink, and an energy drink.

42. The beverage product of claim 36, wherein the beverage product is a ready-to-drink (RTD) beverage product.

43. The beverage product of claim 36, wherein the tea beverage is a non-ready-to-drink (non-RTD) beverage product.

44. A sterile concentrated tea extract made by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; and sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3.

45. The sterile concentrated tea extract of claim 44, wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.

46. The sterile concentrated tea extract of claim 44, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.

47. The sterile concentrated tea extract of claim 44, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.

48. The sterile concentrated tea extract of claim 44, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.

49. The sterile concentrated tea extract of claim 44, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.

50. The sterile concentrated tea extract of claim 44, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.

51. The sterile concentrated tea extract of claim 50, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.

52. The sterile concentrated tea extract of claim 50, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on the total weight of the initial tea extract.

53. The sterile concentrated tea extract of claim 44, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.

54. The sterile concentrated tea extract of claim 44, wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.

55. The sterile concentrated tea extract of claim 44, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.

56. The sterile concentrated tea extract of claim 44, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.

57. The sterile concentrated tea extract of claim 44, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.

58. The sterile concentrated tea extract of claim 44, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.

59. A tea beverage made by a process, the process comprising: steeping tea leaves in water to extract the tea leaves and obtain a steeped tea; separating the tea leaves from the steeped tea; cooling the steeped tea to room temperature or maintaining the steeped tea at a temperature of 5°C to 25°C to obtain an initial tea extract; removing dissolved oxygen from the initial tea extract until a dissolved oxygen concentration of the initial tea extract is 5.0 mg / L or lower; sterilizing the tea extract to obtain a sterile concentrated tea extract, wherein the sterile concentrated tea extract has a dissolved oxygen concentration of 5.0 mg / L or lower and a Brix value of 0.3 to 3.3; mixing the sterile concentrated tea extract with sterile deoxygenated water to obtain a mixture, wherein the sterile deoxygenated water has a dissolved oxygen concentration of 1.0 mg / L or lower; and aseptically filling a container with the mixture to obtain the tea beverage, wherein the tea beverage is a ready to drink (RTD) tea beverage.

60. The tea beverage of claim 59, wherein steeping the tea leaves in water further comprises steeping the tea leaves and an edible or medicinal plant material in water to extract the tea leaves and the edible or medicinal plant material.

61. The tea beverage of claim 59, wherein a weight-to-volume ratio of the tea leaves to water is 10-200 g / L in steeping the tea leaves.

62. The tea beverage of claim 59, wherein the tea leaves are in a dried form or are crushed with a particle size range of 4-50 mesh.

63. The tea beverage of claim 59, wherein the tea leaves are steeped with water at 5°C to 35°C for 15-120 minutes.

64. The tea beverage of claim 59, wherein the tea leaves are steeped with water at 35°C to 100°C for 3-30 minutes.

65. The tea beverage of claim 59, wherein removing the dissolved oxygen comprises adding to the initial tea extract 0.1% to 1.0% by weight of an antioxidant, based on a total weight of the initial tea extract.

66. The tea beverage of claim 65, wherein the antioxidant is selected from the group consisting of ascorbic acid, sodium ascorbate, sodium erythorbate, potassium ascorbate, potassium erythorbate, and any combinations thereof.

67. The tea beverage of claim 65, wherein the antioxidant is added in an amount of 0.2% to 0.6 % by weight, based on the total weight of the initial tea extract.

68. The tea beverage of claim 59, wherein removing the dissolved oxygen comprises treating the initial tea extract under a vacuum of 0.8 bar or below.

69. The tea beverage of claim 59, wherein the Brix value of the sterile concentrated tea extract is from 0.5 to 2.4.

70. The tea beverage of claim 59, wherein the water for steeping the tea leaves has a dissolved oxygen concentration of 1.2 mg / L or less.

71. The tea beverage of claim 59, wherein the tea leaves are steeped in water under stirring, with a stirring rate of 10 RPM to 60 RPM for 10 seconds to 30 minutes.

72. The tea beverage of claim 59, wherein before removing the dissolved oxygen from the initial tea extract, the dissolved oxygen concentration of the initial tea extract is between 5 mg / L and a saturated dissolved oxygen concentration.

73. The tea beverage of claim 59, wherein the tea leaves are selected from the group consisting of green tea leaves, oolong tea leaves, yellow tea leaves, black tea leaves, white tea leaves, dark tea leaves, flower tea leaves, and any combination thereof.

74. The tea beverage of claim 59, wherein the sterile concentrated tea extract and the sterile deoxygenated water are simultaneously added to the container and mixed in the container.

75. The tea beverage of claim 59, wherein the sterile concentrated tea extract is added to the container, and then the sterile deoxygenated water is subsequently added to the container.

76. The tea beverage of claim 59, wherein a volume ratio of the sterile concentrated tea extract to the sterile deoxygenated water is 1 : 1 to 1 : 10.

77. The tea beverage of claim 59, wherein the sterile deoxygenated water is prepared by a deoxygenation process selected from the group consisting of: vacuum degassing, high- temperature degassing, antioxidant treatment, membrane separation, nitrogen displacement, and any combinations thereof.

78. The tea beverage of claim 59, wherein the tea beverage has a dissolved oxygen level of 1.0 mg / L or lower and a Brix value of 1 or lower.

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