Preparation technology of sea-buckthorn Pu'er tea powder rich in flavone

Abstract

The invention belongs to the technical field of tea processing, and discloses a preparation technology of sea-buckthorn Pu'er tea powder rich in flavone. Hippophae rhamnoides leaves and Pu'er tea are used as raw materials and are mixed and crushed, tea soup with quality characteristics of the hippophae rhamnoides Pu'er tea is extracted by adopting a short-time medium-temperature countercurrent extraction technology, and a plate and frame filtration technology, an ultralow-temperature refrigeration cooling centrifugation technology, a reverse osmosis membrane concentration technology, a high-temperature instantaneous sterilization technology and a spray drying technology are combined. The sea-buckthorn Pu'er tea powder has the characteristics of being rich in nutrient components such as flavone and tea polyphenol, good in retention effect of aroma substances, good in taste, high in dissolution rate, strong in antioxidant activity and the like.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, and more specifically to a preparation process of sea buckthorn Pu'er tea powder rich in flavonoids. Background Art

[0002] Seabuckthorn is a deciduous shrub or small tree of the genus Acacia in the family Elaeagnaceae. It is a precious tree species that combines ecological, economic and social benefits and has a very high development and utilization value. Seabuckthorn leaves are rich in nutrients, including total flavonoids, tea polyphenols, amino acids, caffeine and other ingredients. The processed tea has special effects such as anti-oxidation, anti-aging, lipid-lowering and blood pressure-lowering, anti-inflammatory and antibacterial, immune enhancement and prevention of cardiovascular and cerebrovascular diseases.

[0003] Pu'er tea is made from fresh leaves of raw tea, which are dried, withered, rolled, and sun-dried before being fermented using a special "pile-fermentation" process. Pu'er tea is rich in active ingredients such as tea polyphenols, caffeine, theophylline, tea tannins, and vitamins, and has antioxidant, lipid-lowering, and alcoholic fatty liver relief effects.

[0004] Flavonoids are essential natural nutrients for the human body. When the human body lacks flavonoids, it is easy to cause brain and heart dysfunction, vascular hardening, and increased fragility. Flavonoids are easily absorbed by the human body due to their small molecular weight, and can pass through the blood-brain barrier and enter the adipose tissue. Existing studies have shown that flavonoids have many biological activities, including anti-cardiocerebral ischemia, anti-arrhythmia, improving hypoxia tolerance, inhibiting platelet aggregation, anti-ulcer, anti-inflammatory, antioxidant, anti-radiation and enhancing immunity. As a natural antioxidant, flavonoids are also one of the active ingredients in sea buckthorn leaves and Pu'er tea that are relatively abundant and have more prominent functional effects.

[0005] Nowadays, consumers are more inclined to the concept of naturalness and health, and their tastes are becoming more refined, which puts forward higher requirements on the flavor of tea products. However, traditional sea buckthorn tea and Pu'er tea often have serious loss of nutrients, monotonous taste, and easy loss of aroma substances during the preparation process. Therefore, we propose a preparation process of sea buckthorn Pu'er tea powder rich in flavonoids. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to extract tea soup with the quality characteristics of sea buckthorn Pu'er tea by adopting short-time medium-temperature countercurrent extraction technology, and combine plate and frame filtration technology, ultra-low temperature refrigeration and cooling centrifugation technology, reverse osmosis membrane concentration technology, high-temperature instantaneous sterilization technology and spray drying technology to provide a preparation process of sea buckthorn Pu'er tea powder rich in flavonoids, so as to obtain sea buckthorn Pu'er tea powder with the advantages of good retention of nutrients such as flavonoids and tea polyphenols and aroma substances, good taste and strong antioxidant activity.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A preparation process of seabuckthorn Pu'er tea powder rich in flavonoids, specifically comprising the following steps:

[0009] S1: Crushing and sieving: Using seabuckthorn leaves and Pu'er tea as raw materials, crush the raw materials with a crusher, pass through a 40-mesh sieve, and collect the sieved materials;

[0010] S2: First extraction: Add purified water to the sieve under the sieve, stir and soak for 30 minutes to obtain an extract, then add 2 mol / L sodium hydroxide solution to the extract to adjust the pH of the solution to 9-9.5, and then perform short-term medium-temperature countercurrent extraction at 40-55°C for 15-30 minutes to obtain the first extract;

[0011] S3: First filtration: Filter the obtained first extract using a 180-mesh plate-and-frame filter to obtain a first filtrate;

[0012] S4: Second extraction: Add purified water to the sieve after soaking in step S2, stir evenly, and then perform short-term medium-temperature countercurrent extraction at a temperature of 40 to 55° C. for 15 to 30 minutes to obtain a second extract;

[0013] S5: Second filtration: Filter the obtained second extract using a 200-mesh plate and frame filter, and retain the second filtrate;

[0014] S6: Centrifugation: Combine the first filtrate and the second filtrate, subject the combined filtrate to ultra-low temperature cooling and centrifugation, and take the supernatant;

[0015] S7: Adjust pH: add 0.05 mol / L citric acid monohydrate to the supernatant to adjust the pH to 7.0;

[0016] S8: Concentration: The supernatant after adjusting the pH is concentrated by reverse osmosis membrane until the soluble solid content is 35-45%, thereby obtaining a concentrated solution;

[0017] S9: Sterilization: The concentrated solution is sterilized instantaneously at high temperature, the sterilization temperature is 115-135°C, and the sterilization time is 4-15s;

[0018] S10: Drying: spray drying the sterilized concentrated liquid to obtain the seabuckthorn Pu'er tea powder.

[0019] Furthermore, in step S1, the mass ratio of seabuckthorn leaves to Pu'er tea is 4-6:1.

[0020] Furthermore, the amount of purified water added in step S2 is 10 to 20 times the mass of the material under the sieve.

[0021] Furthermore, the amount of purified water added in step S4 is 10 to 20 times the mass of the undersize material after soaking.

[0022] Furthermore, the conditions for the ultra-low temperature refrigeration cooling centrifugation in step S6 are as follows: a centrifugal speed of 3800 to 5000 r / min, a centrifugal time of 15 to 30 min, and a centrifugal temperature of 4°C to 10°C.

[0023] Furthermore, the conditions for the reverse osmosis membrane concentration in step S8 are a concentration pressure of 2.0 MPa and a temperature of 20° C. to 25° C.

[0024] Furthermore, the spray drying conditions in step S10 are as follows: the material feed flow rate is 20-30 mL / min, the air inlet temperature is 180-205° C., and the air outlet temperature is 90-105° C.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. The seabuckthorn puer tea powder of the present invention is prepared by mixing seabuckthorn tea and puer tea according to a preferred ratio. After being prepared by a special process, it not only retains the rich nutrients in seabuckthorn leaves and puer tea, but also has beneficial effects in anti-oxidation, anti-aging, calming the nerves and nourishing the stomach, etc.

[0027] 2. The present invention adopts short-time medium-temperature countercurrent extraction technology to extract tea soup with the quality characteristics of sea buckthorn Pu'er tea. Compared with tea products produced by traditional processes, the extraction efficiency is significantly improved, and by selecting appropriate extraction temperature and extraction time, it is beneficial to fully retain the nutrients while reducing excessive extraction of ineffective ingredients, and obtaining a good taste and aroma.

[0028] 3. In the preparation process of the present invention, the plate and frame filtration technology is used to filter the tea soup extracted by the short-time medium-temperature countercurrent extraction technology to remove the insoluble residue in the tea soup, so as to obtain tea soup without obvious impurities and ensure that the tea soup color is bright and clear.

[0029] 4. The present invention also adopts ultra-low temperature refrigeration and cooling centrifugation technology, which can reduce the destruction of effective ingredients in the filtrate under low temperature conditions and better retain flavor substances. On the other hand, the precipitated insoluble matter can be removed by centrifugation to achieve the purpose of purification.

[0030] 5. In order to effectively avoid the problems of serious browning of tea soup and easy loss of aroma during the concentration process, the present invention uses reverse osmosis membrane concentration technology in the preparation process of sea buckthorn Pu'er tea powder, which can retain the flavor substances in the tea soup to the maximum extent, thereby greatly improving the quality of the tea soup and providing a good technical basis for preparing high-quality sea buckthorn Pu'er tea powder.

[0031] 6. The present invention adopts high-temperature instantaneous sterilization technology and spray drying technology. Since the sterilization and spray drying heating time is short, the nutritional components of sea buckthorn Pu'er tea powder can be retained to the greatest extent, especially the retention rate of flavonoids and tea polyphenols is high, and a sea buckthorn Pu'er tea powder with high dissolution rate, good antioxidant effect and excellent quality is prepared. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the embodiments, but the protection scope is not limited thereto.

[0033] Example 1

[0034] A process for preparing seabuckthorn Pu'er tea powder rich in flavonoids comprises the following steps:

[0035] S1: Crushing and sieving: sea buckthorn leaves and Pu'er tea are used as raw materials, wherein the mass ratio of sea buckthorn leaves to Pu'er tea is 4:1, the raw materials are crushed by a crusher, passed through a 40-mesh sieve, and the sieved material is collected;

[0036] S2: First extraction: add 10 times purified water to the sieve underflow, stir and soak for 30 minutes to obtain an extract, then add 2 mol / L sodium hydroxide solution to the extract to adjust the pH of the solution to 9, and then perform short-term medium-temperature countercurrent extraction at 40°C for 15 minutes to obtain the first extract;

[0037] S3: First filtration: Filter the obtained first extract using a 180-mesh plate-and-frame filter to obtain a first filtrate;

[0038] S4: Second extraction: add 10 times of purified water to the sieve after soaking in step S2, stir evenly, and then perform short-term medium-temperature countercurrent extraction at 40°C for 15 minutes to obtain the second extract;

[0039] S5: Second filtration: Filter the obtained second extract using a 200-mesh plate and frame filter, and retain the second filtrate;

[0040] S6: Centrifugation: Combine the first filtrate and the second filtrate, and subject the combined filtrate to ultra-low temperature cooling and centrifugation at a centrifugal speed of 3800 r / min, a centrifugal time of 15 min, and a centrifugal temperature of 4°C, and take the supernatant;

[0041] S7: Adjust pH: add 0.05 mol / L citric acid monohydrate to the supernatant to adjust the pH to 7.0;

[0042] S8: Concentration: The supernatant after adjusting the pH is concentrated by reverse osmosis membrane, the concentration pressure is 2.0 MPa, the temperature is 20°C, and the soluble solid content is 35%, thereby obtaining a concentrated solution;

[0043] S9: Sterilization: The obtained concentrated solution is sterilized at high temperature instantaneously, the sterilization temperature is 115°C, and the sterilization time is 4s;

[0044] S10: Drying: spray drying the sterilized concentrated solution under the conditions of material feed flow rate of 20 mL / min, air inlet temperature of 180° C., and air outlet temperature of 90° C. to obtain the sea buckthorn Pu'er tea powder.

[0045] Example 2

[0046] A process for preparing flavonoid-rich seabuckthorn Pu'er tea powder comprises the following steps:

[0047] S1: Crushing and sieving: sea buckthorn leaves and Pu'er tea are used as raw materials, wherein the mass ratio of sea buckthorn leaves to Pu'er tea is 5:1, the raw materials are crushed by a crusher, passed through a 40-mesh sieve, and the sieved material is collected;

[0048] S2: First extraction: add 15 times purified water to the sieve underflow, stir and soak for 30 minutes to obtain an extract, then add 2 mol / L sodium hydroxide solution to the extract to adjust the pH of the solution to 9.3, and then perform short-term medium-temperature countercurrent extraction at 48°C for 20 minutes to obtain the first extract;

[0049] S3: First filtration: Filter the obtained first extract using a 180-mesh plate-and-frame filter to obtain a first filtrate;

[0050] S4: Second extraction: add 15 times of purified water to the sieve after soaking in step S2, stir evenly, and then perform short-term medium-temperature countercurrent extraction at 48°C for 20 minutes to obtain the second extract;

[0051] S5: Second filtration: Filter the obtained second extract using a 200-mesh plate and frame filter, and retain the second filtrate;

[0052] S6: Centrifugation: Combine the first filtrate and the second filtrate, and subject the combined filtrate to ultra-low temperature cooling and centrifugation at a centrifugal speed of 4500 r / min, a centrifugal time of 25 min, and a centrifugal temperature of 6°C, and take the supernatant;

[0053] S7: Adjust pH: add 0.05 mol / L citric acid monohydrate to the supernatant to adjust the pH to 7.0;

[0054] S8: Concentration: The supernatant after adjusting the pH is concentrated by reverse osmosis membrane at a concentration pressure of 2.0 MPa and a temperature of 23° C. until the soluble solid content is 40%, thereby obtaining a concentrated solution;

[0055] S9: Sterilization: The concentrated solution is sterilized at high temperature at 120°C for 8 seconds.

[0056] S10: Drying: spray drying the sterilized concentrated solution under the conditions of material feed flow rate of 25 mL / min, air inlet temperature of 190° C., and air outlet temperature of 98° C. to obtain the seabuckthorn Pu'er tea powder.

[0057] Example 3

[0058] A process for preparing flavonoid-rich seabuckthorn Pu'er tea powder comprises the following steps:

[0059] S1: Crushing and sieving: sea buckthorn leaves and Pu'er tea are used as raw materials, wherein the mass ratio of sea buckthorn leaves to Pu'er tea is 6:1, the raw materials are crushed by a crusher, passed through a 40-mesh sieve, and the sieved material is collected;

[0060] S2: First extraction: add 20 times purified water to the sieve underflow, stir and soak for 30 minutes to obtain an extract, then add 2 mol / L sodium hydroxide solution to the extract to adjust the pH of the solution to 9.5, and then perform short-term medium-temperature countercurrent extraction at 55°C for 30 minutes to obtain the first extract;

[0061] S3: First filtration: Filter the obtained first extract using a 180-mesh plate-and-frame filter to obtain a first filtrate;

[0062] S4: Second extraction: add 20 times of purified water to the sieve after soaking in step S2, stir evenly, and then perform short-term medium-temperature countercurrent extraction at 55°C for 30 minutes to obtain the second extract;

[0063] S5: Second filtration: Filter the obtained second extract using a 200-mesh plate and frame filter, and retain the second filtrate;

[0064] S6: Centrifugation: Combine the first filtrate and the second filtrate, and subject the combined filtrate to ultra-low temperature cooling and centrifugation at a centrifugal speed of 5000 r / min, a centrifugal time of 30 min, and a centrifugal temperature of 10°C, and take the supernatant;

[0065] S7: Adjust pH: add 0.05 mol / L citric acid monohydrate to the supernatant to adjust the pH to 7.0;

[0066] S8: Concentration: The supernatant after adjusting the pH is concentrated by reverse osmosis membrane at a concentration pressure of 2.0 MPa and a temperature of 25°C until the soluble solid content is 45%, thereby obtaining a concentrated solution;

[0067] S9: Sterilization: The concentrated solution is sterilized at high temperature at 135°C for 15 seconds.

[0068] S10: Drying: spray drying the sterilized concentrated solution under the conditions of material feed flow rate of 30 mL / min, air inlet temperature of 205° C., and air outlet temperature of 105° C. to obtain the sea buckthorn Pu'er tea powder.

[0069] Performance testing

[0070] 1. Determination method of seabuckthorn Pu'er tea powder index

[0071] Experimental determination reference regulations and process:

[0072] 1. Determination of moisture content: in accordance with GB5009.3;

[0073] 2. Determination of lead: in accordance with GB5009.12;

[0074] 3. Determination of total colony count: in accordance with GB 4789.2;

[0075] 4. Determination of coliform group: in accordance with GB 4789.3;

[0076] 5. Determination of mold: in accordance with GB 4789.15;

[0077] The experimental results are as follows, see Table 1:

[0078] Table 1. Sensory and physical and chemical indicators of seabuckthorn Pu'er tea powder prepared in Examples 1, 2 and 3

[0079] Test results table

[0080] Inspection items index Appearance Brown to dark brown Taste and smell It has the smell that this product should have, the aroma is astringent and peaceful, the taste is pure and sweet, and the soup color is translucent brown-red state The state is uniform, and turbidity or precipitation caused by tea components is allowed Impurities No foreign matter Moisture (%) ≤ 3.0 Lead (Pb) (mg / kg) ≤ 1.0 Total colony count / (cfu / g) ≤ 150 Coliform bacteria / (cfu / g) ≤ 40 Mold / (cfu / g) ≤ 20

[0081] As can be seen from Table 1, the sea buckthorn puer tea powder prepared in each embodiment is evaluated by sensory and physical and chemical indicators. From the results, it can be seen that the sea buckthorn puer tea powder obtained by the preparation process in this application can retain the aroma substances to the greatest extent, and the tea soup is brown-red and bright after brewing with water, and the taste is pure and sweet, which greatly improves the quality of the tea soup. In addition, the water content of the sea buckthorn puer tea powder is low in the test results, and the heavy metal lead content meets the lead content standard in my country's food. After high-temperature instantaneous sterilization, the total number of colonies, coliform counts and mold counts in the sea buckthorn puer tea powder all meet the national standards, and the sterilization effect is obvious.

[0082] 2. Detection of active ingredients in seabuckthorn Pu'er tea powder

[0083] The sea buckthorn Pu'er tea powder obtained in Examples 1, 2 and 3 was tested for active ingredients. The test results are shown in Table 2.

[0084] Table 2. Test results of active ingredients in seabuckthorn Pu'er tea powder

[0085] Total flavonoids (%) Tea polyphenols (%) Caffeine (%) Example 1 10.15±0.26 24.80±0.72 3.76±0.31 Example 2 10.32±0.11 28.15±0.31 3.04±0.27 Example 3 10.20±0.35 26.77±0.12 3.22±0.13

[0086] As a kind of health tea, sea buckthorn pu'er tea is rich in total flavonoids, which have extremely high medicinal and health value. Therefore, the total flavonoid content is an important selection criterion for high-quality sea buckthorn pu'er tea. Tea polyphenols and caffeine are also important components of sea buckthorn pu'er tea. Among them, the tea polyphenol content is the main substance that determines the quality of sea buckthorn pu'er tea, and has the effects of anti-aging, anti-radiation, antibacterial sterilization and prevention and treatment of cardiovascular diseases. The main effect of caffeine is to excite the central nervous system, diuretic and cardiotonic, relieve spasm and relieve asthma, and at the same time affect the taste of tea soup, making it bitter. As a health tea, when selecting high-quality sea buckthorn pu'er tea, it should have the characteristics of high tea polyphenol content and relatively low caffeine content. As can be seen from Table 2, the total flavonoids and tea polyphenols in the sea buckthorn pu'er tea powder obtained in Examples 1, 2, and 3 are relatively rich, and the total flavonoids content is more than 10%, and the caffeine content shows a trend of first decreasing and then increasing, among which the tea polyphenols content and total flavonoids content in Example 2 are the highest, and the caffeine content is the lowest. The results show that after using the preparation process of sea buckthorn Pu'er tea powder in the present application, the sea buckthorn Pu'er tea powder not only retains important nutrients, especially flavonoids and tea polyphenols with high retention rates, but also the sea buckthorn Pu'er tea powder obtained under the preparation process conditions of Example 2 has the characteristics of high-quality sea buckthorn Pu'er tea. Therefore, the preparation process of sea buckthorn Pu'er tea in the present application provides a good technical basis for preparing high-quality sea buckthorn Pu'er tea powder.

[0087] 3. Determination of Antioxidant Capacity of Seabuckthorn Pu'er Tea Powder

[0088] The antioxidant capacity of the seabuckthorn Pu'er tea powder obtained in Examples 1, 2, and 3 was tested using the DPPH free radical scavenging method (DPPH method) and the iron ion reduction / antioxidant capacity method (FRAP method). The results are shown in Table 3.

[0089] Table 3. Results of antioxidant capacity test of seabuckthorn Pu'er tea powder

[0090] DPPH free radical scavenging rate (%) ABTS cationic radical scavenging rate (%) Vitamin C 57.22 60.45 Example 1 85.32 83.61 Example 2 88.13 86.35 Example 3 86.15 85.20

[0091] As can be seen from the above table, the DPPH free radical scavenging rate and ABTS cation radical scavenging rate of the sea buckthorn Pu'er tea powder obtained in Examples 1, 2 and 3 prepared in the present application are both above 83%, indicating that the sea buckthorn Pu'er tea powder obtained in Examples 1, 2 and 3 contains biologically active substances with strong antioxidant capacity, which corresponds to the results in Table 2 and has strong in vitro antioxidant activity, indicating that after adopting the preparation process of sea buckthorn Pu'er tea in the present application, the antioxidant active ingredients in the sea buckthorn Pu'er tea powder can be retained to the greatest extent, and a sea buckthorn Pu'er tea powder with good antioxidant effect and excellent quality can be prepared.

[0092] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A process for preparing seabuckthorn Pu'er tea powder rich in flavonoids, characterized in that: include, S1: Crushing and sieving: Using seabuckthorn leaves and Pu'er tea as raw materials, crush the raw materials with a crusher, pass through a 40-mesh sieve, and collect the sieved materials; S2: First extraction: Add purified water to the sieve under the sieve, stir and soak for 30 minutes to obtain an extract, then add 2 mol / L sodium hydroxide solution to the extract to adjust the pH of the solution to 9-9.5, and then perform short-term medium-temperature countercurrent extraction at 40-55°C for 15-30 minutes to obtain the first extract; S3: First filtration: Filter the obtained first extract using a 180-mesh plate-and-frame filter to obtain a first filtrate; S4: Second extraction: Add purified water to the sieve after soaking in step S2, stir evenly, and then perform short-term medium-temperature countercurrent extraction at a temperature of 40 to 55° C. for 15 to 30 minutes to obtain a second extract; S5: Second filtration: Filter the obtained second extract using a 200-mesh plate and frame filter, and retain the second filtrate; S6: Centrifugation: Combine the first filtrate and the second filtrate, subject the combined filtrate to ultra-low temperature cooling and centrifugation, and take the supernatant; S7: Adjust pH: add 0.05 mol / L citric acid monohydrate to the supernatant to adjust the pH to 7.0; S8: Concentration: The supernatant after adjusting the pH is concentrated by reverse osmosis membrane until the soluble solid content is 35-45%, thereby obtaining a concentrated solution; S9: Sterilization: The concentrated solution is sterilized instantaneously at high temperature, the sterilization temperature is 115-135°C, and the sterilization time is 4-15s; S10: Drying: spray drying the sterilized concentrated liquid to obtain the seabuckthorn Pu'er tea powder.

2. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: In step S1, the mass ratio of seabuckthorn leaves to Pu'er tea is 4-6:

1.

3. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: The amount of purified water added in step S2 is 10 to 20 times the mass of the material under the sieve.

4. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: The amount of purified water added in step S4 is 10 to 20 times the mass of the undersize material after soaking.

5. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: The conditions for the ultra-low temperature refrigeration cooling centrifugation in step S6 are as follows: a centrifugal speed of 3800 to 5000 r / min, a centrifugal time of 15 to 30 min, and a centrifugal temperature of 4°C to 10°C.

6. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: The conditions for reverse osmosis membrane concentration in step S8 are a concentration pressure of 2.0 MPa and a temperature of 20° C. to 25° C.

7. The process for preparing flavonoid-rich seabuckthorn Pu'er tea powder according to claim 1, characterized in that: The spray drying conditions in step S10 are as follows: the material feed flow rate is 20-30 mL / min, the air inlet temperature is 180-205° C., and the air outlet temperature is 90-105° C.