Preparation method of instant berry tea

Abstract

The invention provides a preparation method of instant berry tea, and relates to the technical field of instant drink preparation. The preparation method of the instant berry tea mainly comprises the following steps: drying fresh ampelopsis grossedentata tender stems and leaves, soaking in a saturated sodium chloride solution for a certain period of time, performing plasma treatment, performing high-pressure cold extraction, performing heating ultrasonic extraction, and performing liquid nitrogen freezing and freeze-drying in subsequent drying. According to the instant powder and the preparation method thereof, the defects in the prior art are overcome, the extraction efficiency of effective components of the raspberry tea is improved, the prepared instant powder can be rapidly dissolved in water at a relatively low temperature, and the instant raspberry tea can be conveniently brewed in various environments.

Description

Technical Field

[0001] The present invention relates to the technical field of instant beverage preparation, and particularly relates to a preparation method of instant moyeam tea. Background Art

[0002] Instant tea is an important deep-processed tea product, which refers to a new type of beverage in granular or powdery form that is easily soluble in water without tea residues and is processed from finished tea, semi-finished tea, tea by-products or fresh tea leaves through processes such as extraction, filtration, concentration, and drying. Moyeam tea is one of the common substitute teas on the market at present. However, different from conventional black tea and green tea, moyeam tea is prepared by processing the tender stems and leaves of Ampelopsis grossedentata. Compared with ordinary tea drinks, moyeam tea contains rich flavonoid compounds, among which dihydromyricetin has the highest content. The quality of moyeam tea itself is not only judged by its flavor but also related to the content of dihydromyricetin.

[0003] Most of the instant teas on the existing market are prepared from common teas such as green tea or black tea, and there are few products of instant moyeam tea. Generally speaking, tea drinks are usually soaked or brewed with warm water or hot water. However, with the development of society and the changing tastes of young people who prefer iced drinks, so there are gradually more categories of iced tea drinks. Instant tea has also gradually developed from the original hot water brewing to normal temperature water or even cold water brewing. However, at present, many instant teas have problems such as low solubility, incomplete melting, and turbid soup color at lower temperatures.

[0004] For the preparation process of instant moyeam tea, two main points need to be noted: 1. Ensure the content of effective components in instant moyeam tea; 2. Ensure the solubility of instant moyeam tea. Most of the conventional preparation methods of existing instant moyeam tea are to extract moyeam tea with a solvent and then dry it to obtain instant powder. However, the solvent selection is diverse. The extraction efficiency of the overall effective components by water extraction is not high. Especially, the use of heated hot water extraction will damage the effective components (such as dihydromyricetin) to a certain extent. While the extraction of effective components with solvents such as ethanol has better extraction efficiency, problems such as solvent pollution will affect the quality of instant tea. And usually, water at a relatively high temperature is required for better dissolution during brewing, and it has poor solubility in normal temperature or even low temperature water, and the overall tea soup is relatively turbid, without the clear texture of tea drinks, affecting the overall sensory experience.

[0005] Based on the above problems, how to promote the subsequent low-temperature dissolution of moyeam tea extract on the basis of improving the extraction efficiency of effective components of moyeam tea is an important technical innovation direction and problem in the preparation of instant moyeam tea at the present stage. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a preparation method of instant Ampelopsis grossedentata tea, which effectively improves the extraction rate of active ingredients in the tender stems and leaves of Ampelopsis grossedentata, and the prepared instant powder can be quickly dissolved in water at a relatively low temperature, realizing the convenient brewing of instant Ampelopsis grossedentata tea in various environments.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A preparation method of instant Ampelopsis grossedentata tea, the preparation method comprising the following steps: S1. Soaking treatment: Select fresh tender stems and leaves of Ampelopsis grossedentata from June to August, sun-dry until the water content is 10-12%, then place them in a saturated sodium chloride solution and soak for 3-5 minutes under a pressure of 0.5 MPa, and then take them out and wash with pure water to obtain preliminarily treated leaves; S2. Plasma treatment: Spread the above-mentioned preliminarily treated leaves and perform plasma treatment with a mixed gas of argon and nitrogen for 2-3 minutes, and then take them out to obtain pretreated leaves; S3. High-pressure cold extraction: Crush the above-mentioned pretreated leaves mixed with ice cubes, and then place them in an environment of 4-6 °C and sequentially adjust the pressure to stand and extract within the ranges of 0.2-0.4 MPa, 2-4 MPa, and 8-10 MPa, and then press and filter to obtain a filtrate and filter residue; S4. Secondary extraction: Mix the above-mentioned filter residue with pure water, perform ultrasonic oscillation at a temperature of 60-80 °C and then centrifuge, separate the precipitate and then combine the above-mentioned filtrate to obtain a mixed extraction solution for standby; S5. Drying treatment: Freeze the above-mentioned mixed extraction solution with liquid nitrogen, adjust the temperature for freeze-drying, and then pulverize to obtain instant Ampelopsis grossedentata tea powder.

[0008] Preferably, the temperature of soaking in the saturated sodium chloride solution in step S1 is normal temperature.

[0009] Preferably, in step S2, the volume ratio of argon to nitrogen is 1-3:1-3, and the flow rate of the mixed gas is 100-150 mL / min, and the treatment power is 300-420 W.

[0010] Preferably, in step S3, the mass ratio of the pretreated leaves to the ice cubes is 1:3-5.

[0011] Preferably, in step S3, stand and extract for 1-2 hours under a pressure of 0.2-0.4 MPa, stand and extract for 30-40 minutes under a pressure of 2-4 MPa, and stand and extract for 10-20 minutes under a pressure of 8-10 MPa.

[0012] Preferably, in step S4, the mass ratio of the filter residue to the pure water is 1:3-5, and the pH value of the feed liquid is adjusted to 5.5-6.

[0013] Preferably, in step S4, the power of ultrasonic oscillation is 400 - 600 W, and the time of ultrasonic oscillation is 15 - 30 min.

[0014] Preferably, in step S4, the rotation speed of centrifugation is 4000 - 5000 r / min, and the time of centrifugation is 10 - 15 min.

[0015] Preferably, in step S5, the time of liquid nitrogen freezing is 1 - 2 h, the temperature of freeze - drying is - 55°C ± 5°C, and the vacuum degree of freeze - drying is 10 - 20 Pa.

[0016] The present invention provides a preparation method of instant ampelopsis grossedentata tea. Compared with the prior art, its advantages are as follows: In the early stage of the present invention, the fresh tender stems and leaves of ampelopsis grossedentata are soaked in saturated sodium chloride solution under high pressure for a short time, effectively destroying the cells of the tender stems and leaves of ampelopsis grossedentata preliminarily. Combining with subsequent plasma treatment can extract more effective components in high - pressure cold extraction. And by controlling the pressure of high - pressure cold extraction, subsequent ultrasonic secondary extraction and freeze - drying after liquid nitrogen freezing, it can effectively improve the rapid dissolution of the final dried product in water at low temperature and normal temperature, ensure the clarity of the solution after dissolution, and comprehensively improve the quality of the finally obtained instant ampelopsis grossedentata tea. Detailed implementation mode

[0017] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0018] Embodiment: Refer to the following preparation method of instant ampelopsis grossedentata tea: (1) Soaking treatment: The fresh tender stems and leaves of ampelopsis grossedentata are sun - dried until the water content is 10 - 12% to obtain dry leaves as raw materials. The same batch of dry leaves are respectively placed in saturated sodium chloride solution and soaked at a pressure of 0.5 MPa in a normal - temperature environment, and then taken out and washed with pure water to obtain preliminarily treated leaves; (2) The above - mentioned preliminarily treated leaves are laid flat and treated with a mixed gas of argon and nitrogen with an equal volume ratio at a gas flow rate of 120 mL / min and a power of 350 W for 160 s by plasma, and then taken out to obtain pre - treated leaves; (3) The above - mentioned pre - treated leaves are mixed with 4 times the mass of ice cubes and crushed, then the static extraction temperature is controlled, and different pressures are adjusted for static extraction, followed by pressing and filtering to obtain filtrate and filter residue; (4) Mix the above-mentioned filter residue with 4 times its volume of pure water, and then perform ultrasonic oscillation treatment at 500 W for 12 min at 70 °C. Then, centrifuge at a speed of 4500 r / min for 15 min. After separating the precipitate, combine the above filtrates to obtain a mixed extract for standby; (5) Freeze the above mixed extract in liquid nitrogen for 90 min, then take it out, adjust the temperature to -55 °C ± 5 °C, freeze-dry it under a vacuum of 15 Pa, and then pulverize it to obtain instant tengcha powder.

[0019] According to the above preparation method, set experimental groups 1-10 respectively with reference to Table 1 below, and obtain different instant tengcha powders by using different preparation parameters: Table 1

[0020] Calculate the mass of the instant tengcha powder extracted from 1 kg of dry raw leaves in each group, detect and calculate the mass of dihydromyricetin extracted from 1 kg of dry raw leaves in each group, and the percentage of dihydromyricetin in the total extract. The specific results are shown in Table 2 below Table 2

[0021] It can be seen from the above detection that in experimental group 1, the treatment of soaking with saturated sodium chloride is not adopted, and in experimental group 2, the treatment of soaking for a short time (1 min) is adopted. Finally, the mass of the obtained instant tengcha powder is less, and the overall content of dihydromyricetin is also lower. In experimental group 5, the treatment of soaking with saturated sodium chloride for 8 min is adopted, but the mass of the obtained instant tengcha powder is even less than that of experimental groups 3 and 4. This may be because the soaking time of the saturated sodium chloride solution is too long, resulting in a higher degree of damage to the tengcha cells, and some extractable components are more dissolved into the saturated sodium chloride solution or lost during subsequent rinsing. Therefore, it is more reasonable to control the soaking time of the saturated sodium chloride solution at 3-5 min; the overall yield of instant tengcha powder and the content of dihydromyricetin in experimental group 6 are both higher; experimental groups 7-9 adopt static extraction under a single pressure, and the overall extraction amount and extraction rate of dihydromyricetin are both lower.

[0022] In summary, the overall extraction efficiency of the instant tengcha powder prepared in experimental groups 3, 4, 6, and 10 is relatively high; In addition, set a CK group. Based on the principle of single-factor experiment, mix the instant tengcha powders of experimental groups 3, 6, 10 and the CK group with normal temperature water (22 ± 3 °C) and ice water (2 ± 2 °C) at a mass ratio of 1:25 respectively, stir evenly, observe the dissolution of the instant tengcha powder in each group, filter after standing for 2 min, dry the filter residue at 45 °C with hot air, and calculate the dissolution rate of the instant tengcha powder in each group (dissolution rate = (total mass - mass of dry filter residue) / total mass × 100%). The specific dissolution rates are shown in Table 3 below Table 3

[0023] The preparation method of the instant Ampelopsis grossedentata tea powder in the above CK group is as follows: The fresh young stems and leaves of Ampelopsis grossedentata are sun-dried until the water content is 11% to obtain raw material dry leaves. The raw material dry leaves are crushed and screened through a 40-mesh sieve, and then countercurrent extraction is carried out with pure water at a temperature of 35°C, controlling the flow rate at 20 m3 / h. After extraction for 3 h, the extract is concentrated and then spray-dried to obtain instant Ampelopsis grossedentata tea powder.

[0024] In experimental group 3, it dissolves quickly when brewed with normal temperature water and ice water. After stirring and standing for 2 min, the overall color of the tea soup is clear and there is no residue of particulate matter. Among them, the tea soup with normal temperature water is clearer, and the tea soup with ice water is slightly turbid, but the overall solubility is good and the color is uniform.

[0025] In experimental group 6, it can be dissolved in time when brewed with normal temperature water. After stirring and standing for 2 min, the overall color of the tea soup is uniform and there is a small amount of particulate residue. When brewed with ice water, the overall tea soup is not very uniform and is relatively turbid.

[0026] In experimental group 10, it can be basically dissolved when brewed with normal temperature water, but there are obvious particulate dispersions in the tea soup and the uniformity is poor. When brewed with ice water, the solubility is slightly worse than that at normal temperature and the sense of granulation is more obvious.

[0027] Regardless of whether it is brewed with normal temperature water or ice water, the overall solubility of the CK group is poor and the overall sense of granulation is obvious. Especially when brewed with ice water, the undissolved particles adhere to the wall seriously.

[0028] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the steps and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of instant vine tea, characterized in that, The preparation method includes the following steps: S1. Soaking treatment: Select fresh tender stems and leaves of Ampelopsis grossedentata in June - August, dry them in the sun until the water content is 10 - 12%, then soak them in a saturated sodium chloride solution at a pressure of 0.5 MPa for 3 - 5 minutes, take them out and wash them with pure water to obtain preliminarily treated leaves; S2. Plasma treatment: After spreading the above - mentioned preliminarily treated leaves, perform plasma treatment on them with a mixed gas of argon and nitrogen for 2 - 3 minutes, and take them out to obtain pretreated leaves; S3. High - pressure cold extraction: Crush the above - mentioned pretreated leaves together with ice cubes, then place them in an environment of 4 - 6 °C, and sequentially adjust the pressure to be within the range of 0.2 - 0.4 MPa, 2 - 4 MPa, and 8 - 10 MPa for static extraction, and then press and filter to obtain a filtrate and filter residue; S4. Secondary extraction: Mix the above - mentioned filter residue with pure water, perform ultrasonic oscillation at a temperature of 60 - 80 °C, then centrifuge, separate the precipitate, and combine the above - mentioned filtrate to obtain a mixed extraction solution for standby; S5. Drying treatment: Freeze the above - mentioned mixed extraction solution with liquid nitrogen, adjust the temperature for freeze - drying, and then pulverize to obtain instant Ampelopsis grossedentata tea powder.

2. The preparation method according to claim 1, characterized in that: In step S1, the temperature of soaking in the saturated sodium chloride solution is room temperature.

3. The preparation method according to claim 1, characterized in that: In step S2, the volume ratio of argon to nitrogen is 1 - 3∶1 - 3, the flow rate of the mixed gas is 100 - 150 mL / min, and the treatment power is 300 - 420 W.

4. The preparation method according to claim 1, characterized in that: In step S3, the mass ratio of the pretreated leaves to ice cubes is 1∶3 - 5.

5. The preparation method according to claim 1, characterized in that: In step S3, static extraction is carried out for 1 - 2 h at a pressure of 0.2 - 0.4 MPa, for 30 - 40 min at a pressure of 2 - 4 MPa, and for 10 - 20 min at a pressure of 8 - 10 MPa.

6. The preparation method according to claim 1, characterized in that: In step S4, the mass ratio of the filter residue to pure water is 1∶3 - 5, and the pH value of the material - liquid is adjusted to 5.5 - 6.

7. The preparation method according to claim 1, characterized in that: In step S4, the power of ultrasonic oscillation is 400 - 600 W, and the time of ultrasonic oscillation is 15 - 30 min.

8. The preparation method according to claim 1, characterized in that: In step S4, the rotation speed of centrifugation is 4000 - 5000 r / min, and the time of centrifugation is 10 - 15 min.

9. The preparation method according to claim 1, characterized in that: In step S5, the time of freezing with liquid nitrogen is 1 - 2 h, the temperature of freeze - drying is - 55 °C ± 5 °C, and the vacuum degree of freeze - drying is 10 - 20 Pa.

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