Hawthorn Liubao Tea and its Preparation Method

Abstract

This invention discloses a method for preparing hawthorn Liubao tea. Addressing the technical problems of existing blends of hawthorn leaves or flowers with Liubao tea, such as a strong sour and astringent taste, easy loss of active ingredients, and poor flavor integration, this invention employs a low-temperature vacuum withering and fixation process on hawthorn raw materials, followed by multiple cycles of gradient-temperature steaming and baking. Before each steaming process, a maltodextrin aqueous solution is sprayed onto the hawthorn raw materials. Simultaneously, Liubao tea undergoes cold-air withering, rolling, and baking. The mixture is then blended at a 5:1 mass ratio, followed by constant-temperature steaming and segmented baking to obtain hawthorn Liubao tea. This method effectively removes unpleasant off-flavors from the hawthorn raw materials while retaining active ingredients such as flavonoids, achieving a deep fusion of hawthorn flavor and the aged aroma of Liubao tea. This invention is primarily used to prepare hawthorn Liubao tea with a harmonious and unified flavor, high retention rate of active ingredients, and stable quality, meeting the industrial production and consumption needs of healthy compound tea beverages.

Description

Technical Field

[0001] This invention belongs to the field of tea processing technology, specifically relating to a hawthorn Liubao tea and its preparation method. Background Technology

[0002] Liubao tea belongs to the dark tea category and is renowned for its four unique characteristics: red color, strong aroma, aged flavor, and mellow taste. It possesses a distinctive areca nut and aged aroma, and its flavor and health benefits continuously improve with age. Hawthorn (including hawthorn leaves and flowers) is rich in flavonoids, organic acids, and other active ingredients, offering benefits such as aiding digestion, promoting blood circulation, and lowering blood lipids. Combining hawthorn with Liubao tea to develop a compound tea beverage that combines tea aroma with fruit / floral fragrance and synergistic health benefits has promising market prospects.

[0003] However, the following technical problems exist in the existing preparation of mixed hawthorn and tea beverages: Hawthorn raw materials (especially leaves and flowers) contain strong sour and astringent tastes, grassy smells and bitter substances. Traditional simple drying or high-temperature roasting is difficult to effectively remove these unpleasant off-flavors, resulting in an unharmonious taste and mixed aroma when combined with Liubao tea.

[0004] Traditional blending processes (such as simple blending followed by drying) make it difficult for the flavors of the two ingredients to blend deeply, and the finished product often presents a separate "blended" feel rather than an integrated complex flavor.

[0005] The heat-sensitive active ingredients (such as flavonoids and hawthorn acid) in hawthorn raw materials are easily lost under high temperature treatment, which reduces the health benefits of the product.

[0006] When using hawthorn leaves, their tough tissue and thick waxy layer make it difficult to effectively break down their cell walls through conventional processing, resulting in the difficulty in releasing their active ingredients and flavor, and the finished product has a coarse and hard texture.

[0007] When hawthorn flowers are used, their aroma components are delicate and highly volatile. Under conventional processes, the fragrance dissipates in large quantities, making it difficult to retain and stabilize in the finished product.

[0008] Therefore, there is an urgent need to develop a preparation method that can effectively remove the unpleasant off-flavors of hawthorn raw materials, retain their active ingredients and good flavor, and achieve a deep and firm integration with the flavor of Liubao tea. Summary of the Invention

[0009] The object of the present invention is to overcome at least the aforementioned defects and to provide advantages that will be described later.

[0010] Another objective of this invention is to provide a hawthorn Liubao tea with harmonious flavor, stable quality, high retention rate of active ingredients, and compliance with food safety regulations, as well as a method for its preparation.

[0011] To achieve these objectives and other advantages of the present invention, a method for preparing hawthorn Liubao tea is now provided, comprising: Hawthorn leaves or flowers are used as raw materials. The hawthorn is withered at a low temperature of 0.06-0.08 MPa and 25-30℃ until its weight is half of the initial weight. Then, a drum-type blanching machine is used at 125-140℃ for 5-7 minutes. Finally, it is treated in steam at 60-70℃ for 26-28 minutes. During the steam treatment, the temperature is increased by 1°C every 4 minutes based on the initial temperature, and then maintained at a maximum of 70°C until the end of the steam treatment time. After that, the temperature is transferred to 75°C to 80°C for 30 to 35 minutes for baking. During the baking process, the temperature is increased by 1°C every 5 minutes based on the initial temperature, and then maintained at a maximum of 80°C until the end of the baking time. The steam treatment and baking treatment are repeated 3 to 5 times, and the parameters of the steam treatment and baking treatment are consistent with the first time in each repetition. Before the start of each steam treatment, a 3% to 5% maltodextrin aqueous solution is evenly sprayed onto the surface of hawthorn leaves or hawthorn flowers, and the spraying amount is 5% to 8% of the initial mass of hawthorn leaves or hawthorn flowers to obtain the treated hawthorn raw material.

[0012] The Liubao tea is processed by cold air withering and rolling, and then baked at 70℃ to 80℃ for 20 to 30 minutes until the moisture content of the Liubao tea is reduced to 6% to 8%, thus obtaining the processed Liubao tea.

[0013] Mix the processed hawthorn raw materials and processed Liubao tea at a mass ratio of 5:1, place them in a constant temperature steam at 60℃ to 70℃ for 20-22 minutes, with a relative humidity of 60%, and then transfer them to segmented roasting. The segmented roasting is carried out at 70℃ for 12-15 minutes, at 80℃ for 10-15 minutes, and at 85℃ for 5 minutes to obtain hawthorn Liubao tea.

[0014] The above-mentioned solution effectively solves the problems of strong astringency, easy loss of active ingredients, and poor flavor integration with Liubao tea in existing technologies by combining low-temperature vacuum withering with multiple cycles of gradient heating steam and baking, and using maltodextrin for protection. Low-temperature vacuum withering gently removes the grassy smell while retaining floral aroma and active substances; gradient heating and cyclic treatment fully transform the bitter substances in the hawthorn raw material, while promoting a deep interplay between the aged aroma of Liubao tea and the fruity / floral aroma of hawthorn. Maltodextrin forms a protective film during multiple thermal cycles to prevent flavor loss. The final product is a bright red tea soup with a mellow and smooth taste, a balanced sweet and sour flavor, possessing both the mellowness of Liubao tea and the unique flavor of hawthorn, with a high retention rate of health-promoting components and significantly improved quality stability.

[0015] Preferably, the rolling process for Liubao tea specifically includes: rolling for 8 to 10 minutes on a rolling machine at a light pressure setting, with the rolling pressure controlled at 0 to 200 N, until the tea cell breakage rate reaches 15% to 25%; then switching to a medium pressure setting on the rolling machine and rolling for 12 to 15 minutes, with the rolling pressure controlled at 200 to 400 N, until the tea cell breakage rate reaches 45% to 55%; finally switching to a light pressure setting or no pressure setting on the rolling machine and rolling for 5 to 8 minutes, with the rolling pressure controlled at 0 to 50 N; during the rolling process, spraying a mist of water every 5 minutes, with each spray amount being 0.5% to 1.0% of the tea mass.

[0016] The above-mentioned method precisely controls the cell breakage rate of Liubao tea within the optimal range of 45%-55% through a finely segmented kneading process of "light pressure-medium pressure-light pressure" and timed spraying. This solves the problem of insufficient or excessive cell breakage in traditional kneading, which leads to a weak or bitter tea soup. The initial light pressure initially shapes the tea leaves and slightly breaks down the cell walls. The medium pressure in the middle stage allows for the full release of effective components, providing a material basis for subsequent transformation. The later light or no pressure is used to shape the tea leaves and allow the tea juice to be absorbed back into the leaves. Regular spraying of mist-like water regulates the moisture dynamics during the kneading process, preventing the leaves from drying out and breaking, and promoting the uniform dissolution and redistribution of internal components. The resulting Liubao tea has tightly rolled and intact leaves, with a smooth and stable extraction of internal components during brewing. It has a high tea soup concentration with low bitterness and astringency, significantly improved brewing endurance, and can better carry and integrate external flavors when mixed with hawthorn raw materials.

[0017] Preferably, when the hawthorn raw material is hawthorn leaves, the hawthorn leaves are kneaded after the fixation process and before the steam treatment. Specifically, this includes alternating between light-pressure kneading and high-pressure kneading. Light-pressure kneading is performed by kneading on the light-pressure setting of the kneading machine for 18 to 22 minutes, with the kneading pressure controlled at 0 to 100 N. High-pressure kneading is performed by kneading on the high-pressure setting of the kneading machine for 18 to 22 minutes, with the kneading pressure controlled at 400 to 500 N. During the kneading process, a mist of water is sprayed every 5 minutes, with each spray amount being 0.5% to 1.0% of the tea leaf mass. Finally, the kneading is performed until the tea leaf cell breakage rate is between 45% and 55%.

[0018] The above-mentioned method addresses the characteristics of hawthorn leaves—their tough tissue and thick waxy layer—by employing a long-duration, alternating high and low pressure kneading process. This effectively solves the problems of difficult cell wall breakage, insufficient bitterness transformation, and a coarse texture in hawthorn leaves. The long kneading time of 110-130 minutes, combined with a high pressure of 400-500N, powerfully breaks down the fibrous tissue and waxy layer of the hawthorn leaves, achieving a cell breakage rate of 45%-55%, similar to that of tea leaves. Regular spraying with water softens the fibers and lubricates the leaves, preventing them from pulverizing under high pressure. After this kneading process, the bitter substances (such as tannins) in the hawthorn leaves can fully interact with oxygen and heat during the subsequent steaming and roasting cycles, leading to transformation. The effective components (such as flavonoids) are also more easily dissolved. The final product features hawthorn leaves fully integrated into the tea, with no roughness and a harmonious flavor.

[0019] Preferably, the cold air withering treatment of Liubao tea fresh leaves is as follows: place the Liubao tea fresh leaves in a withering trough, control the ambient temperature to 18℃ to 22℃, the relative humidity to 65% to 75%, and the cold air speed to 0.8 to 1.2 m / s; turn them over lightly every 30 minutes during the withering process, and wither until the moisture content of the fresh leaves drops to 68% to 72%, and the difference between the moisture content of the leaves and the moisture content of the leaf stems is less than 5%.

[0020] The above method achieves "low-temperature slow withering" of Liubao tea leaves by precisely controlling the temperature, humidity, wind speed, and turning frequency during cold air withering. This solves the problem of uneven water loss and unstable quality caused by "green stems and yellow leaves" in traditional withering. The low temperature environment of 18-22℃ effectively inhibits the respiration and enzymatic oxidation of fresh leaves, preventing reddening. The high humidity environment of 65%-75% slows down the rate of water evaporation from the leaf surface, allowing sufficient time for water in the veins and stems to migrate evenly to the leaves, thus ensuring that the final moisture content difference between the leaves and stems is less than 5%. Light turning every 30 minutes ensures that the water loss of the upper and lower layers of fresh leaves is synchronized. This uniform and synchronized withering effect makes the fresh leaves physically soft and easy to roll, and chemically, it allows the grassy smell to dissipate fully and generates more aroma precursors, laying a high-quality foundation for subsequent rolling and fermentation. The finished tea has no raw grassy smell or musty taste, and has a fresh and mellow flavor.

[0021] Preferably, when the hawthorn raw material is hawthorn leaves, it also includes: Select dried tangerine peel that has been stored for 6 to 7 years, wash it, spray it evenly with water, and steam it in a steamer at 100℃ for 2-3 minutes until softened. After taking it out, cut it into tangerine peel strips of 0.4-0.6 cm. Place the tangerine peel strips in a baking environment at 42-45℃ for 15-20 minutes until the moisture content of the tangerine peel strips drops to 12%-15%, and you will get the processed tangerine peel strips.

[0022] Mix the processed hawthorn raw materials, processed Liubao tea, and processed dried tangerine peel strips in a mass ratio of 5:1:0.3-0.5, and place them in a constant temperature steam at 60℃ to 70℃ for 20-22 minutes with a relative humidity of 60%. Then, proceed with segmented roasting, roasting at 70℃ for 12-15 minutes, at 80℃ for 10-15 minutes, and at 85℃ for 5 minutes to obtain hawthorn Liubao tea.

[0023] The above solution successfully resolved the issues of aroma conflict and taste disharmony during flavor layering by introducing aged tangerine peel (Chenpi) aged for 6-7 years and pre-treating it with steaming, slicing, and baking. The aging process transforms the pungent limonene in the tangerine peel's volatile oils into milder aromatic compounds; short-term steaming after spraying with water softens the hard peel, preventing powder formation during slicing; and low-temperature baking at 42-45℃ further gently reduces moisture content, fixing its mellow aroma. The treated tangerine peel slices are then mixed with hawthorn and Liubao tea in a specific ratio, followed by constant-temperature steaming and segmented baking. This results in a complex aroma profile of "top-middle-base notes" formed by the unique citrus aroma of the tangerine peel, the fruity aroma of the hawthorn, and the aged aroma of the Liubao tea. The slight spiciness of the tangerine peel enhances the sweetness of the tea soup, resulting in a rich, full-bodied, and rounded overall flavor profile, while also providing the synergistic health benefits of the three ingredients.

[0024] Preferably, the spraying treatment of the maltodextrin aqueous solution specifically includes: Take a maltodextrin aqueous solution with a mass concentration of 1.5%-2.5% and spray it before the first steam treatment. The amount of spraying is 2%-3% of the initial mass of hawthorn raw material.

[0025] Take a 3.0%-4.0% maltodextrin aqueous solution and spray it before the start of the third steam treatment. The amount of spraying is 2%-3% of the initial mass of hawthorn raw material.

[0026] Take a 4.5%-5.5% maltodextrin aqueous solution and spray it after the last steam treatment and before the last baking treatment. The amount of spraying is 1%-2% of the initial mass of hawthorn raw material.

[0027] After each spraying, place the hawthorn raw material in a sealed container, evacuate to a vacuum degree of 0.04-0.06 MPa, and maintain for 2-3 minutes to allow the maltodextrin solution to penetrate into the interior of the hawthorn raw material under the pressure difference; then release the vacuum and let it stand at normal pressure for 5-8 minutes.

[0028] The above-mentioned method effectively solves the problems of dextrin only adhering to the surface, uneven protection, and insufficient penetration depth by spraying different concentrations of maltodextrin in stages and supplementing it with vacuum permeation. The first application uses a low concentration of dextrin, utilizing vacuum permeation to open pathways for pre-permeation; the third application uses a medium concentration of dextrin to build a protective network within the tissue; the final application, after steam treatment and before baking, uses the vacuum pressure difference to deeply "press" the dextrin into the deep layers of the already treated material, forming a gradient protective layer from the inside out. Vacuum permeation, driven by pressure difference, allows the solution to penetrate deep into the tissue along the intercellular spaces, followed by static placement at normal pressure to allow the dextrin to fully bind with the cell walls. This method greatly reduces browning and flavor loss in hawthorn raw materials during thermal cycling, ensuring uniform color and lasting aroma in the finished product. Simultaneously, the encapsulation effect of dextrin also delays quality deterioration during storage.

[0029] Preferably, before the first maltodextrin spray, a chitosan solution with a mass concentration of 0.1%-0.3% is sprayed evenly onto the surface of the hawthorn raw material in a mist, the spray amount being 2%-4% of the initial mass of the hawthorn raw material, and left to stand for 3-5 minutes; the degree of deacetylation in the chitosan solution is ≥90%.

[0030] The above solution cleverly solves the problem of uneven maltodextrin solution penetration caused by poor surface wettability of hawthorn raw materials (especially those with thick wax layers) through pre-spraying with chitosan solution. Chitosan, as a natural cationic polysaccharide, possesses excellent surface activity and film-forming properties. After spraying, the amino and hydroxyl groups in its molecules interact with the wax and cuticle layers on the surface of hawthorn leaves, reducing surface tension and thus disrupting the "spherical" contraction tendency of droplets. This allows the subsequently sprayed maltodextrin solution to form a uniform liquid film and spread rapidly. Simultaneously, chitosan itself also has good antioxidant and antibacterial activity, which synergistically enhances the color-protecting and freshness-preserving effects of maltodextrin. A 3-5 minute standing period ensures sufficient adsorption and spreading of chitosan molecules, creating uniform and moist interface conditions for subsequent vacuum penetration, significantly improving the uniformity and efficiency of maltodextrin penetration.

[0031] Preferably, the maltodextrin is selected from low DE value maltodextrin with a glucose equivalent of 6-10 and high DE value maltodextrin with a DE value of 15-20, and is used in a mass ratio of 2:1-3:1.

[0032] The above solution, by combining low DE value (6-10) and high DE value (15-20) maltodextrins, achieves multiple functions of "penetration-film formation-stabilization" that a single dextrin cannot possess, thus solving the problem of single dextrins offering only partial benefits. Low DE value dextrins have a large molecular weight, good film-forming properties, and strong moisture resistance, forming a dense protective film on the material surface to prevent flavor loss and excessive moisture absorption. High DE value dextrins have a small molecular weight, strong permeability, and high sweetness, allowing them to quickly penetrate deep into the material structure under vacuum, acting as an "anchor" and internal filler. The two are combined in a 2:1-3:1 ratio, working synergistically: the high DE value dextrin inside locks in the flavor, while the low DE value dextrin outside isolates the environment. The final product not only has a high flavor retention rate during processing but also does not easily absorb moisture and clump during storage, maintaining good crispness and aroma release characteristics, and significantly extending shelf life.

[0033] Preferably, during the atmospheric pressure settling period after each vacuum permeation, a transglutaminase solution with a mass concentration of 0.2%-0.5% is sprayed evenly onto the surface of the hawthorn raw material in a mist form 2-3 minutes after the start of settling, with the spray amount being 1%-2% of the initial mass of the hawthorn raw material, and then settling continues until the total settling time reaches 5-8 minutes.

[0034] The above solution addresses the issues of easy backflow and weak binding force of the maltodextrin protective layer during repeated thermal cycles by introducing transglutaminase treatment and enzymatic ripening. Transglutaminase catalyzes the formation of cross-links between glucose residues in maltodextrin and lysine and glutamine residues on the cell wall proteins / fibers of hawthorn raw materials, transforming the physically adsorbed dextrin layer into a covalently bonded "molecular network." Spraying during the atmospheric pressure settling period takes advantage of the window of opportunity when the permeated dextrin is not yet fixed, allowing for in-situ cross-linking. The low-temperature, high-humidity ripening (40-45℃, 55%-60% RH) after the third spray provides the optimal environment for the enzymatic reaction and promotes the maturation and homogenization of the cross-linked network. This stable three-dimensional network structure effectively resists dextrin migration and rearrangement during subsequent high-temperature, high-humidity treatments, ensuring the protective effect throughout the entire cycle. The final product also achieves a slow and sustained release of flavor compounds during brewing.

[0035] After the third spraying and completion of vacuum penetration, and before the final baking process, place the hawthorn raw material in an environment with a temperature of 40-45℃ and a relative humidity of 55%-60% for 15-20 minutes, and gently turn it over once every 5 minutes at a speed of 20-30 revolutions per minute.

[0036] Preferably, when the hawthorn raw material is hawthorn blossoms, after the processed hawthorn raw material is mixed with the processed Liubao tea and placed in constant temperature steam treatment, a flavor pre-curing treatment is also performed, specifically including: After mixing the processed hawthorn raw materials with the processed Liubao tea at a mass ratio of 5:1, the mixture is placed in a sealed pressure vessel and subjected to 3-5 gradient pressure pulse cycles. Each cycle includes: pressurizing to 0.2-0.3 MPa and maintaining it for 1-2 minutes to allow the flavor components in the hawthorn raw materials to penetrate into the Liubao tea under pressure; then rapidly depressurizing to atmospheric pressure within 3-5 seconds; and allowing the mixture to stand at atmospheric pressure for 1-2 minutes between adjacent cycles to complete the gradient pressure pulse penetration.

[0037] After gradient pressure pulse infiltration is completed, the mixture is placed in an ultrasonic oscillator at a frequency of 28-40 kHz and a power density of 0.3-0.5 W / cm³. 2 Under the conditions of 8-12 minutes, the temperature is increased from 25°C to 35°C at a rate of 2°C every 2 minutes during the ultrasonic treatment to complete the ultrasonic treatment.

[0038] Two to three minutes before the end of the ultrasonic treatment, spray a tannin enzyme solution with a mass concentration of 0.1% to 0.3% onto the surface of the mixture in a mist-like manner. The amount of spraying is 1% to 2% of the total mass of the mixture, thus completing the flavor anchoring cross-linking.

[0039] The flavor-anchored crosslinked mixture is placed in an environment with a temperature of 35-40℃ and a relative humidity of 35%-40% for pre-drying for 15-20 minutes until the overall moisture content of the mixture drops to 15%-18%. During the pre-drying process, the mixture is turned over every 5 minutes at a speed of 15-25 rpm to prevent the material surface from forming a crust. After the pre-drying is completed, it is then processed according to the constant temperature steam treatment and segmented baking process described in claim 1.

[0040] The above-mentioned scheme, employing a series of flavor pre-curing processes—pressure pulse, ultrasonic oscillation, tannin enzyme anchoring, and pre-drying—is specifically designed to address the problem of hawthorn flower aroma being easily lost and difficult to anchor in Liubao tea. The pressure pulse utilizes the "micro-pump" effect generated by the dramatic pressure change to drive the aromatic oils in the hawthorn flowers to penetrate into the loose tissues of the Liubao tea. Subsequently, gradient-heated ultrasonic oscillation, through cavitation and mechanical vibration, further disperses the essential oil droplets and promotes their uniform dispersion, while the gentle heat accelerates diffusion. The tannin enzyme solution is sprayed before the end of the ultrasonic treatment, which moderately hydrolyzes the ester-type catechins in the Liubao tea, exposing more binding sites (such as glycosidic bonds) with floral components, thus achieving "flavor anchoring." The final pre-drying removes surface moisture, preventing flavor evaporation with steam during subsequent steam treatment. This process firmly "locks" the delicate floral aroma of hawthorn flowers into the tea leaves, resulting in a finished tea with a rich and lasting floral fragrance that blends perfectly with the tea liquor without any separation.

[0041] Advantages of this invention: 1. This invention effectively removes the sour and grassy smell of hawthorn raw materials by using low-temperature vacuum withering combined with gradient heating steam-baking multiple cycles, and with the protection of maltodextrin, while retaining its active ingredients and natural flavor. It also achieves a deep and integrated fusion with the aged aroma of Liubao tea. The resulting product has a mellow and smooth taste, harmonious flavor, and a high retention rate of health-promoting components.

[0042] 2. By segmented rolling and cold-air withering for Liubao tea, and alternating high and low pressure long-term rolling for hawthorn leaves, the cell breakage rate and water loss uniformity are precisely controlled, laying the physical and chemical foundation for high-quality finished tea.

[0043] 3. By spraying maltodextrin in stages and at gradient concentrations, combined with technologies such as vacuum permeation, chitosan wetting, compound dextrin, and transglutaminase cross-linking, a robust and stable flavor protection and sustained-release network from the inside out was constructed, which greatly improved the processing tolerance and storage stability of the product.

[0044] 4. By using a pressure pulse-ultrasound-enzyme anchoring pre-curing treatment on hawthorn flowers, the problem of directional migration and firm anchoring of delicate floral fragrance was creatively solved, expanding the application potential of hawthorn flowers in tea drinks and enriching the aroma profile of the product.

[0045] 5. By introducing pre-treated tangerine peel, a complex aroma profile of "aged aroma, fruity aroma, and citrus aroma" is formed, further enhancing the product's flavor profile and synergistic health benefits. Detailed Implementation

[0046] The present invention will now be described in further detail to enable those skilled in the art to implement it based on the description. It should be noted that the kneading time for hawthorn leaves is relatively long (110-130 minutes). To avoid premature fermentation or flavor changes due to mechanical friction causing the material to heat up during kneading, the present invention controls the ambient temperature at 20-25℃ during the kneading process and sprays a mist of water every 5 minutes to ensure that the material temperature never exceeds 35℃, thus ensuring uniform kneading and not affecting the quality of the raw materials.

[0047] Example 1 The preparation method of hawthorn Liubao tea, in which hawthorn leaves are used as the raw material, is as follows: Step 1: Take fresh hawthorn leaves and place them in a vacuum withering tank. Wither them at a vacuum of 0.07 MPa and a temperature of 28°C until their weight is half of the initial weight. Then, use a drum-type withering machine to wither the leaves at 130°C for 6 minutes. After withering, place the hawthorn leaves in 65°C steam for 27 minutes, increasing the temperature from 65°C to 70°C at a rate of 1°C every 4 minutes, and then hold the temperature. Next, bake at 78°C for 32 minutes, increasing the temperature from 75°C to 80°C at a rate of 1°C every 5 minutes, and then hold the temperature. Repeat the above steaming and baking treatments a total of 4 times. Before each steaming treatment, evenly spray a 4% (w / w) maltodextrin aqueous solution, with the spray amount being 6.5% of the initial hawthorn leaf weight. The processed hawthorn leaves are then obtained.

[0048] Step Two: Take fresh Liubao tea leaves and place them in a withering trough. Control the ambient temperature at 20℃, relative humidity at 70%, and cold air speed at 1.0 m / s. Gently turn the leaves every 30 minutes until the moisture content of the fresh leaves reaches 70%, and the difference in moisture content between the leaves and stems is less than 5%. Then proceed with rolling: first, roll at a light pressure (100N) for 9 minutes until the cell breakage rate is 20%; then roll at a medium pressure (300N) for 13 minutes until the cell breakage rate is 50%; finally, roll at a light pressure (25N) for 6 minutes. During the rolling process, spray a mist of water every 5 minutes, with each spray amount being 0.75% of the tea leaf mass. After rolling, bake at 75℃ for 25 minutes until the moisture content is 7%, obtaining the processed Liubao tea.

[0049] Step 3: Mix the processed hawthorn leaves and processed Liubao tea at a mass ratio of 5:1, place them in a constant temperature steam at 65℃ for 21 minutes (relative humidity 60%), and then bake them in stages: bake at 70℃ for 13 minutes, bake at 80℃ for 12 minutes, and bake at 85℃ for 5 minutes to obtain hawthorn Liubao tea.

[0050] Example 2 The preparation method of hawthorn Liubao tea, wherein the hawthorn raw material is hawthorn leaves, is based on Example 1, and the specific steps are as follows: Step 1: Hawthorn Leaf Processing: Same as Step 1 in Example 1, but with the addition of a rolling process after the initial fixation and before steam treatment: Alternate between light rolling (50N, 20 minutes) and high rolling (450N, 20 minutes), for a total of 120 minutes. During the rolling process, spray a mist of water every 5 minutes, each time at a rate of 0.75% of the tea leaf mass, until the cell breakage rate reaches 50%. The rest is the same as Step 1 in Example 1, resulting in properly processed hawthorn leaves.

[0051] Step 2: All operations and parameters in this step are completely consistent with Step 2 of Example 1, resulting in processed Liubao tea.

[0052] Step 3: Select 6.5-year-old dried tangerine peel, wash it, spray it with water, steam it in a 100℃ steamer for 2.5 minutes, take it out and cut it into 0.5cm strips, then bake it at 43.5℃ for 17 minutes until the moisture content is 13.5%, and you will get the processed dried tangerine peel strips.

[0053] Step 4: Mix the processed hawthorn leaves, processed Liubao tea, and processed dried tangerine peel strips evenly in a mass ratio of 5:1:0.4, that is, for every 500 grams of processed hawthorn leaves, use 100 grams of processed Liubao tea and 40 grams of processed dried tangerine peel strips.

[0054] The mixed materials were placed in a constant-temperature steam treatment device, with the steam temperature controlled at 65℃ and the relative humidity at 60%, and the treatment lasted for 21 minutes. During the treatment, the materials were kept evenly spread, with a thickness not exceeding 3 cm, to ensure that the steam could penetrate the material layer evenly.

[0055] After the constant temperature steam treatment is completed, the material is immediately transferred to the baking equipment for segmented baking. The specific baking parameters are as follows: First stage: bake at 70℃ for 13 minutes; Second stage: bake at 80℃ for 12 minutes; Third stage: bake at 85℃ for 5 minutes.

[0056] During the segmented roasting process, the materials should be spread out evenly, and slightly turned over once at the end of each stage to ensure even heating. After roasting, remove the materials and let them cool naturally to room temperature to obtain hawthorn Liubao tea.

[0057] Example 3 The preparation method of hawthorn Liubao tea, using hawthorn leaves as the raw material, is as follows, based on Examples 1 and 2: Step 1: Take fresh hawthorn leaves and place them in a vacuum withering tank. Set the vacuum level to 0.07 MPa and the temperature to 28°C for low-temperature vacuum withering. Withering continues until the weight of the hawthorn leaves is reduced to half of their initial weight, i.e., the weight loss rate reaches 50%.

[0058] After withering, the hawthorn leaves are fed into a drum-type blanching machine. The blanching temperature is set to 130℃ and the blanching time is 6 minutes to perform blanching treatment, thereby deactivating the activity of endogenous enzymes such as polyphenol oxidase and fixing the quality.

[0059] After blanching, the hawthorn leaves are kneaded. This is done by alternating between light and high-pressure kneading, for a total kneading time of 120 minutes. Light kneading is performed for 20 minutes on the light setting of the kneading machine, with a kneading pressure controlled at 50N; high-pressure kneading is performed for 20 minutes on the high-pressure setting of the kneading machine, with a kneading pressure controlled at 450N. This alternating cycle of light and high pressure is repeated three times (i.e., light pressure 20 minutes, high pressure 20 minutes, light pressure 20 minutes, high pressure 20 minutes, light pressure 20 minutes, high pressure 20 minutes). During the kneading process, a mist of water is sprayed every 5 minutes, with each spray amount being 0.75% of the hawthorn leaf's weight. Kneading continues until the hawthorn leaf cell breakage rate reaches 50%.

[0060] A 0.2% (w / w) chitosan aqueous solution was prepared by dissolving chitosan in a 1% (v / v) acetic acid aqueous solution. The degree of deacetylation of the chitosan used was 92%. The chitosan aqueous solution was then uniformly sprayed onto the surface of hawthorn leaves in a mist form, at a spraying amount of 3% of the initial mass of the hawthorn leaves (i.e., the mass of fresh hawthorn leaves). After spraying, the hawthorn leaves were left to stand at room temperature and pressure for 4 minutes to allow the chitosan to be fully adsorbed onto the surface of the hawthorn leaves.

[0061] Low DE value maltodextrin with a glucose equivalent (DE value) of 6-10 and high DE value maltodextrin with a DE value of 15-20 are mixed at a mass ratio of 2.5:1 and stirred evenly to obtain compound maltodextrin for later use.

[0062] Take a 2.0% (w / w) solution of compound maltodextrin and spray it evenly onto the surface of hawthorn leaves, the spraying amount being 2.5% of the initial mass of the hawthorn leaves (i.e., the mass of fresh hawthorn leaves). After spraying, immediately place the hawthorn leaves in a sealed container, evacuate to a vacuum of 0.05 MPa, and maintain this vacuum for 2.5 minutes. After the maintenance time is over, release the vacuum to normal pressure and begin atmospheric pressure settling. Timing begins after the start of atmospheric pressure settling. When the settling time reaches 2.5 minutes, spray a 0.35% (w / w) transglutaminase solution evenly onto the surface of the hawthorn leaves in a mist, the spraying amount being 1.5% of the initial mass of the hawthorn leaves. After spraying the transglutaminase, continue settling, ensuring a total atmospheric pressure settling time of 6.5 minutes (i.e., 6.5 minutes from the start of vacuum release). After completing the above treatment, perform the first steam treatment, followed by the first baking treatment. The steam treatment process involves starting at 65°C and increasing the temperature to 70°C at a rate of 1°C every 4 minutes, for a total treatment time of 27 minutes. The baking treatment involves starting at 75°C and increasing the temperature to 80°C at a rate of 1°C every 5 minutes, for a total treatment time of 32 minutes.

[0063] After the first baking process, a second steam treatment is performed, followed by a second baking process. The processing parameters for the steam treatment and baking process are the same as above.

[0064] After the second baking treatment, a 3.5% (w / w) maltodextrin aqueous solution was evenly sprayed onto the surface of the hawthorn leaves, with a spray volume of 2.5% of the initial weight of the hawthorn leaves. After spraying, the hawthorn leaves were placed in a sealed container, and a vacuum was drawn to 0.05 MPa and maintained for 2.5 minutes. After the maintenance time, the vacuum was released to atmospheric pressure, and atmospheric pressure settling began. 2.5 minutes after the start of atmospheric pressure settling, a 0.35% (w / w) transglutaminase solution was evenly sprayed onto the surface of the hawthorn leaves in a mist, with a spray volume of 1.5% of the initial weight of the hawthorn leaves. Settling continued after spraying, ensuring a total atmospheric pressure settling time of 6.5 minutes. After completing the above treatment, a third steam treatment was performed, followed by a third baking treatment. The treatment parameters for the steam treatment and baking treatment were the same as above.

[0065] After the third baking treatment, a 5.0% (w / w) maltodextrin aqueous solution was evenly sprayed onto the surface of the hawthorn leaves, with a spray volume of 1.5% of the initial weight of the hawthorn leaves. After spraying, the hawthorn leaves were placed in a sealed container, and a vacuum was drawn to 0.05 MPa and maintained for 2.5 minutes. After the maintenance time, the vacuum was released to normal pressure, and the leaves were allowed to stand at normal pressure. 2.5 minutes after the start of the normal pressure standing period, a 0.35% (w / w) transglutaminase solution was evenly sprayed onto the surface of the hawthorn leaves in a mist, with a spray volume of 1.5% of the initial weight of the hawthorn leaves. The leaves were allowed to stand for a total of 6.5 minutes at normal pressure. After the above standing period, the hawthorn leaves were placed in an environment with a temperature of 42.5℃ and a relative humidity of 57.5% for 17 minutes for heat and humidity treatment. During the treatment, the leaves were gently turned every 5 minutes at a speed of 25 rpm. After the enzymatic ripening treatment is completed, a fourth (final) baking treatment is performed according to the baking parameters mentioned above. At this point, the hawthorn leaf processing is complete, and the processed hawthorn leaves are obtained.

[0066] Step 2: All operations and parameters in this step are completely consistent with Step 2 of Example 1, resulting in processed Liubao tea.

[0067] Step 3: All operations and parameters in this step are completely consistent with Step 3 of Example 2, resulting in processed dried tangerine peel strips.

[0068] Step 4: All operations and parameters in this step are completely consistent with Step 4 of Example 2, and hawthorn Liubao tea is obtained.

[0069] Example 4 The preparation method of hawthorn Liubao tea, using hawthorn flowers as the raw material, is based on Example 1, and the specific steps are as follows: Step 1: Take fresh hawthorn flowers and place them in a vacuum withering tank. Set the vacuum level to 0.07 MPa and the temperature to 28℃ for low-temperature vacuum withering. Withering continues until the weight of the hawthorn flowers is reduced to half of their initial weight, i.e., the weight loss rate reaches 50%. After withering, transfer the hawthorn flowers to a drum-type blanching machine. Set the blanching temperature to 130℃ and the blanching time to 6 minutes for blanching treatment to deactivate endogenous enzymes such as polyphenol oxidase and fix the quality.

[0070] After blanching, the hawthorn flowers were steamed at 65℃ for 27 minutes, with the temperature increasing from 65℃ to 70℃ at a rate of 1℃ every 4 minutes, and then held at that temperature. They were then baked at 78℃ for 32 minutes, with the temperature increasing from 75℃ to 80℃ at a rate of 1℃ every 5 minutes, and then held at that temperature. This steaming and baking process was repeated four times. Before each steaming treatment, a 4% maltodextrin aqueous solution was evenly sprayed onto the surface of the hawthorn flowers, at a rate of 6.5% of the initial mass of the hawthorn flowers (i.e., the mass of fresh hawthorn flowers), resulting in properly treated hawthorn flowers.

[0071] Step 2: All operations and parameters in this step are completely consistent with Step 2 of Example 1, resulting in processed Liubao tea.

[0072] Step 3: Mix the processed hawthorn flowers and processed Liubao tea evenly at a mass ratio of 5:1, that is, 100 grams of processed Liubao tea for every 500 grams of processed hawthorn flowers. Ensure that the materials are thoroughly mixed during the mixing process.

[0073] The mixed materials were placed in a sealed pressure vessel and subjected to four gradient pressure pulse cycles. The specific procedures for each cycle were as follows: Pressurization: The pressure vessel was pressurized to 0.25 MPa and maintained for 1.5 minutes, allowing the flavor components of the hawthorn flowers to penetrate the Liubao tea under pressure. Rapid depressurization: After the holding time, the pressure was rapidly released to atmospheric pressure within 4 seconds. Atmospheric pressure resting: Between adjacent cycles, the mixture was allowed to rest at atmospheric pressure for 1.5 minutes. These steps were repeated for a total of four pressure pulse cycles.

[0074] After gradient pressure pulse infiltration is completed, the mixture is removed from the pressure vessel and placed in an ultrasonic oscillator. The ultrasonic frequency is set to 34 kHz and the power density to 0.4 W / cm³. 2 The treatment time was 10 minutes. During the ultrasonic treatment, the temperature was gradually increased from 25°C to 35°C at a rate of 2°C every 2 minutes. Ultrasonic treatment can further break down the essential oil droplets in the flavor components and promote their uniform dispersion.

[0075] Two and a half minutes before the end of the ultrasonic treatment (i.e., 7.5 minutes after the start of the ultrasonic treatment), a 0.2% tanninase solution was sprayed evenly onto the surface of the mixture in a mist form. The spray volume was 1.5% of the total mass of the mixture (i.e., the total mass of hawthorn flowers and Liubao tea). Tanninase can moderately hydrolyze ester-type catechins in Liubao tea, exposing more binding sites with floral aroma components and achieving flavor anchoring. Ultrasonic treatment continued after spraying until the end.

[0076] After ultrasonic treatment, the mixture is removed from the ultrasonic oscillator and placed in an environment with a temperature of 37.5℃ and a relative humidity of 37.5% for pre-drying for 17 minutes, until the overall moisture content of the mixture drops to 16.5%. During pre-drying, the mixture is turned over every 5 minutes at a speed of 20 rpm to prevent crust formation on the surface. The purpose of pre-drying is to remove excess moisture from the surface of the mixture and prevent excessive evaporation of flavor with water vapor during subsequent constant-temperature steam treatment.

[0077] The pre-cured mixture is placed in a constant-temperature steam treatment device, with the steam temperature controlled at 65℃ and the relative humidity at 60%, for 21 minutes. During the treatment, the material should be spread evenly, with a thickness not exceeding 3 cm, to ensure uniform steam penetration.

[0078] After the constant-temperature steam treatment is completed, the material is immediately transferred to the roasting equipment for segmented roasting. Specific parameters are as follows: Stage 1: 70℃ for 13 minutes; Stage 2: 80℃ for 12 minutes; Stage 3: 85℃ for 5 minutes. During the segmented roasting process, the material is kept evenly spread out, and is slightly turned once at the end of each stage. After the segmented roasting is completed, the material is removed and placed in a clean, ventilated environment to cool naturally to room temperature, thus obtaining the finished hawthorn Liubao tea.

[0079] Comparative Example 1 The preparation method of hawthorn Liubao tea, based on Example 1, includes the following specific steps: Step 1: Take fresh hawthorn leaves and place them in a vacuum withering tank. Set the vacuum level to 0.07 MPa and the temperature to 28°C for low-temperature vacuum withering. Withering continues until the weight of the hawthorn leaves is reduced to half of their initial weight, i.e., the weight loss rate reaches 50%.

[0080] After the hawthorn leaves have withered, they are fed into a drum-type blanching machine. The blanching temperature is set to 130℃ and the blanching time is 6 minutes for blanching treatment.

[0081] After blanching, the hawthorn leaves are kneaded. This is done by alternating between light and high-pressure kneading, for a total kneading time of 120 minutes. The specific procedure is as follows: Light kneading: Use the light pressure setting on the kneading machine, controlling the kneading pressure at 50N, for 20 minutes. High-pressure kneading: Switch to the high-pressure setting on the kneading machine, controlling the kneading pressure at 450N, for 20 minutes. Repeat this alternating cycle (20 minutes of light pressure, 20 minutes of high pressure) for a total of 3 cycles (120 minutes in total). During the kneading process, spray a mist of water onto the surface of the hawthorn leaves every 5 minutes, with each spray amount being 0.75% of the leaf's weight. After kneading, the cell breakage rate of the hawthorn leaves is checked and found to be 50%.

[0082] The kneaded hawthorn leaves were placed in a steam treatment device for a one-time steam treatment. The steam treatment parameters were: initial temperature 65℃, increasing to 70℃ at a rate of 1℃ every 4 minutes, with a total treatment time of 27 minutes.

[0083] After steam treatment, the hawthorn leaves are immediately transferred to a baking device for a one-time baking process. The baking parameters are: initial temperature 75℃, increasing to 80℃ at a rate of 1℃ every 5 minutes, for a total processing time of 32 minutes. The resulting hawthorn leaves are then processed.

[0084] Step 2: All operations and parameters in this step are completely consistent with Step 2 of Example 1, resulting in processed Liubao tea.

[0085] Step 3: Mix the processed hawthorn leaves and processed Liubao tea evenly at a mass ratio of 5:1, that is, 100 grams of processed Liubao tea for every 500 grams of processed hawthorn leaves. Place the mixture in a constant temperature steam treatment device, controlling the steam temperature at 65℃ and the relative humidity at 60%, for 21 minutes. During the treatment, the material should be spread evenly, with a thickness not exceeding 3 cm. After the constant temperature steam treatment, immediately transfer the material to a roasting device for segmented roasting. The specific parameters are as follows: Stage 1: 70℃ roasting for 13 minutes; Stage 2: 80℃ roasting for 12 minutes; Stage 3: 85℃ roasting for 5 minutes. During the segmented roasting process, the material should be kept evenly spread, and the material should be slightly turned once at the end of each stage. After the segmented roasting is completed, remove the material and allow it to cool naturally to room temperature to obtain hawthorn Liubao tea.

[0086] Comparative Example 2 The preparation method of hawthorn Liubao tea, based on Example 4, includes the following specific steps: Step 1: Take fresh hawthorn flowers and place them in a vacuum withering tank. Set the vacuum level to 0.07 MPa and the temperature to 28°C for low-temperature vacuum withering. Withering continues until the weight of the hawthorn flowers is reduced to half of their initial weight, i.e., the weight loss rate reaches 50%.

[0087] After the hawthorn flowers have withered, they are sent into a drum-type blanching machine. The blanching temperature is set to 130℃ and the blanching time is 6 minutes for blanching treatment.

[0088] Hawthorn flowers were subjected to four cycles of steam treatment and baking treatment to obtain properly treated hawthorn flowers. The steam treatment and baking treatment parameters were identical for each cycle, as follows: Steam treatment: initial temperature 65℃, increased to 70℃ at a rate of 1℃ every 4 minutes, total treatment time 27 minutes. Baking treatment: initial temperature 75℃, increased to 80℃ at a rate of 1℃ every 10 minutes, total treatment time 32 minutes. Before each steam treatment, a 4% maltodextrin aqueous solution was evenly sprayed onto the surface of the hawthorn flowers, the spray amount being 6.5% of the initial mass of the hawthorn flowers (i.e., the mass of fresh hawthorn flowers). Steam treatment was then performed directly after spraying.

[0089] Step 2: All operations and parameters in this step are completely consistent with Step 2 of Example 4, resulting in processed Liubao tea.

[0090] Step 3: Mix the processed hawthorn flowers and processed Liubao tea evenly at a mass ratio of 5:1, that is, 100 grams of processed Liubao tea for every 500 grams of processed hawthorn flowers. Ensure that the materials are thoroughly mixed during the mixing process.

[0091] The mixed materials are placed in a constant-temperature steam treatment device, with the steam temperature controlled at 65℃ and the relative humidity at 60%, and the treatment is continued for 21 minutes. During the treatment, the materials should be spread evenly, with a thickness not exceeding 3 cm.

[0092] After the constant-temperature steam treatment is completed, the material is immediately transferred to the baking equipment for segmented baking. The specific parameters are as follows: Stage 1: 70℃ baking for 13 minutes; Stage 2: 80℃ baking for 12 minutes; Stage 3: 85℃ baking for 5 minutes. During the segmented baking process, the material is kept evenly spread out, and is slightly turned once at the end of each stage.

[0093] After the segmented roasting is completed, the material is taken out and allowed to cool naturally to room temperature to obtain hawthorn Liubao tea.

[0094] Comparative test I. Experimental Design Test samples: Hawthorn Liubao tea samples were prepared according to the preparation processes of Examples 1-4 and Comparative Examples 1-2. Each process was repeated to prepare 3 batches, with each batch containing 500 g of sample. The samples were numbered as Examples 1-1 to Examples 4-3 and Comparative Examples 1-1 to Comparative Examples 2-3. After all samples were prepared, they were placed in a dry environment away from light at room temperature for 24 hours before various indicators were tested.

[0095] Experimental design: The core test indicators are sensory quality, retention rate of active ingredients, water content stability and flavor integration. The indicator data of each example and comparative sample are compared.

[0096] Test environment: All tests were conducted in a standard laboratory environment with a temperature of 25℃ and a relative humidity of 60%, using the same model of testing instruments and equipment to eliminate environmental and equipment interference.

[0097] II. Testing Methods (a) Sensory quality rating A panel of 10 professionals with Level 2 or higher national tea appraiser qualifications was invited to conduct a blind evaluation of the samples, referring to the "Sensory Evaluation Methods for Tea" (GB / T23776-2018). The evaluation was conducted from four dimensions: aroma (30 points), mouthfeel (25 points), flavor (30 points), and form (15 points). The highest and lowest scores were removed, and the average score was taken to calculate the comprehensive sensory score (out of 100 points). The specific criteria for the scoring dimensions were as follows: the aroma dimension assessed the integration of the fresh aroma of hawthorn leaves / hawthorn flowers with the aged aroma of Liubao tea and the persistence of the aroma; the mouthfeel dimension assessed the smoothness of the tea soup and the degree of absence of astringency; the flavor dimension assessed the mellowness and sweetness and the degree of absence of off-flavors; and the form dimension assessed the uniformity of the tea leaves and hawthorn leaves / hawthorn flowers and the looseness of the dry tea.

[0098] (ii) Detection of active ingredient retention rate High-performance liquid chromatography (HPLC) was used to determine the content of characteristic flavonoids and organic acids in hawthorn leaves or flowers in each sample, referring to SN / T4592-2016 "Determination of Total Flavonoids in Exported Foods" and "National Food Safety Standard for Determination of Organic Acids in Foods" (GB5009.157-2021). The retention rate of the two components was calculated based on the initial content of the two components in fresh hawthorn leaves or flowers (retention rate = component content in sample / initial component content in fresh hawthorn leaves or flowers × 100%). The determination of flavonoids was performed using a combination of spectrophotometry and HPLC. Flavonoids were extracted from the sample by reflux in a 70% methanol water bath, and the absorbance was measured at 510 nm after color development with sodium nitrite-aluminum nitrate. The characteristic flavonoid components were accurately quantified using HPLC.

[0099] (III) Moisture content stability test Referring to the "Determination of Moisture in Tea" (GB / T8304-2023), the initial moisture content of each sample was determined after preparation. Then, all samples were stored in an environment with room temperature (25℃) and relative humidity of 65% for 30 days, and the moisture content was measured again. The rate of change of moisture content was calculated (rate of change = (moisture content after storage - initial moisture content) / initial moisture content × 100%). The smaller the absolute value of the rate of change, the better the stability of moisture content. There is no judgment of positive or negative deviation.

[0100] (iv) Flavor integration test Gas chromatography-mass spectrometry (GC-MS) was used to detect the relative contents of characteristic aroma components (linalool and geraniol) of hawthorn leaves or hawthorn flowers and characteristic aroma components (theaflavins and terpenes) of Liubao tea in each sample. The flavor synergy coefficient formula was used to calculate the flavor synergy (out of 100). The higher the synergy value, the better the flavor synergy between hawthorn leaves or hawthorn flowers and Liubao tea, and the less disjointed the flavors.

[0101] III. Test Results and Analysis 1. The average data of various test indicators of each embodiment and comparative sample are shown in Table 1. All data are the average values ​​of the test results of 3 batches of samples, and are rounded to one decimal place.

[0102] Table 1:

[0103] 2. Analysis and Conclusion According to the data in Table 1, the differentiated preparation process designed for the physicochemical properties of hawthorn leaves and hawthorn flowers in this invention can significantly improve the sensory quality, active ingredient retention rate, moisture content stability and flavor integration of hawthorn Liubao tea compared with conventional preparation methods (Comparative Example 1, Comparative Example 2). It effectively solves the core problems of poor flavor integration between hawthorn raw materials and Liubao tea, easy loss of active ingredients and unstable product quality.

[0104] The process parameters of this invention are clear and highly reproducible. The hawthorn Liubao tea prepared has a good sensory experience, high nutritional value and excellent storage stability, which meets the market demand for high-quality and diversified healthy tea drinks.

[0105] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily implemented by those skilled in the art. Therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. A method for preparing hawthorn Liubao tea, characterized in that, include: Hawthorn leaves or flowers are used as raw materials. The hawthorn is withered at a low temperature of 0.06-0.08 MPa and 25-30℃ until its weight is half of the initial weight. Then, a drum-type blanching machine is used at 125-140℃ for 5-7 minutes. Finally, it is treated in steam at 60-70℃ for 26-28 minutes. During the steam treatment, the temperature is increased by 1°C every 4 minutes based on the initial temperature, and then kept at a maximum of 70°C until the end of the steam treatment time. After that, the temperature is transferred to 75°C to 80°C for baking for 30 to 35 minutes. During the baking process, the temperature is increased by 1°C every 5 minutes based on the initial temperature, and then kept at a maximum of 80°C until the end of the baking time. The steam treatment and baking treatment are repeated 3 to 5 times. The parameters of the steam treatment and baking treatment are the same as the first time in each repetition. Before the start of each steam treatment, a maltodextrin aqueous solution with a mass concentration of 3% to 5% is evenly sprayed on the surface of hawthorn leaves or hawthorn flowers. The amount of spraying is 5% to 8% of the initial mass of hawthorn leaves or hawthorn flowers to obtain the treated hawthorn raw material. The Liubao tea is processed by cold air withering and rolling, and then baked at 70℃ to 80℃ for 20 to 30 minutes until the moisture content of the Liubao tea is 6% to 8%, thus obtaining the processed Liubao tea. Mix the processed hawthorn raw materials and processed Liubao tea at a mass ratio of 5:1, place them in a constant temperature steam at 60℃ to 70℃ for 20-22 minutes, with a relative humidity of 60%, and then transfer them to segmented roasting. The segmented roasting is carried out at 70℃ for 12-15 minutes, at 80℃ for 10-15 minutes, and at 85℃ for 5 minutes to obtain hawthorn Liubao tea.

2. The method for preparing hawthorn Liubao tea as described in claim 1, characterized in that, The kneading process of Liubao tea specifically includes: Use a rolling machine on the light pressure setting for 8 to 10 minutes, with the rolling pressure controlled at 0 to 200 N, until the tea cell breakage rate reaches 15% to 25%; then switch to the medium pressure setting on the rolling machine and knead for 12 to 15 minutes, with the rolling pressure controlled at 200 to 400 N, until the tea cell breakage rate reaches 45% to 55%; finally, switch to the light pressure setting or no pressure setting on the rolling machine and knead for 5 to 8 minutes, with the rolling pressure controlled at 0 to 50 N. Spray a mist of water every 5 minutes during the kneading process, with each spray amount being 0.5% to 1.0% of the tea's weight.

3. The method for preparing hawthorn Liubao tea as described in claim 1, characterized in that, When the raw material for hawthorn is hawthorn leaves, the hawthorn leaves are kneaded after blanching and before steam treatment, specifically including: The process involves alternating between light and high-pressure kneading. Light kneading is performed on the light setting of the kneading machine for 18 to 22 minutes, with the kneading pressure controlled at 0 to 100 N. High-pressure kneading is performed on the high setting of the kneading machine for 18 to 22 minutes, with the kneading pressure controlled at 400 to 500 N. During the kneading process, spray a mist of water every 5 minutes, with each spray amount being 0.5% to 1.0% of the tea's weight. Finally, knead until the tea cell breakage rate is between 45% and 55%.

4. The method for preparing hawthorn Liubao tea as described in claim 1, characterized in that, The specific cold-air withering process for fresh Liubao tea leaves is as follows: Place the fresh Liubao tea leaves in a withering trough, control the ambient temperature to 18℃ to 22℃, the relative humidity to 65% to 75%, and the cold air speed to 0.8 to 1.2 m / s; turn them over lightly every 30 minutes during the withering process, until the moisture content of the fresh leaves drops to 68% to 72%, and the difference between the moisture content of the leaves and the moisture content of the leaf stalks is less than 5%.

5. The method for preparing hawthorn Liubao tea according to any one of claims 1-4, characterized in that, When the raw material for hawthorn is hawthorn leaves, it also includes: Select dried tangerine peel that has been stored for 6 to 7 years, wash it, spray it evenly with water, and steam it in a steamer at 100℃ for 2-3 minutes until softened. After removing it, cut it into tangerine peel strips of 0.4-0.6 cm. Place the tangerine peel strips in a baking environment at 42-45℃ for 15-20 minutes until the moisture content of the tangerine peel strips drops to 12%-15%, and you will get the processed tangerine peel strips. Mix the processed hawthorn raw materials, processed Liubao tea, and processed dried tangerine peel strips in a mass ratio of 5:1:0.3-0.5, and place them in a constant temperature steam at 60℃ to 70℃ for 20-22 minutes with a relative humidity of 60%. Then, proceed with segmented roasting, roasting at 70℃ for 12-15 minutes, at 80℃ for 10-15 minutes, and at 85℃ for 5 minutes to obtain hawthorn Liubao tea.

6. The method for preparing hawthorn Liubao tea as described in claim 1, characterized in that, The spraying treatment of maltodextrin aqueous solution specifically includes: A 1.5%-2.5% (w / w) maltodextrin aqueous solution was sprayed before the first steam treatment, with the spraying amount being 2%-3% of the initial mass of the hawthorn raw material. Before the third steam treatment, spray a 3.0%-4.0% maltodextrin aqueous solution at a concentration of 2%-3% of the initial mass of the hawthorn raw material. Take a 4.5%-5.5% maltodextrin aqueous solution and spray it after the last steam treatment and before the last baking treatment. The amount of spraying is 1%-2% of the initial mass of hawthorn raw material. After each spraying, place the hawthorn raw material in a sealed container, evacuate to a vacuum degree of 0.04-0.06 MPa, and maintain for 2-3 minutes to allow the maltodextrin solution to penetrate into the interior of the hawthorn raw material under the pressure difference; then release the vacuum and let it stand at normal pressure for 5-8 minutes.

7. The method for preparing hawthorn Liubao tea as described in claim 6, characterized in that, Before the first maltodextrin spray, spray the surface of the hawthorn raw material with a chitosan solution of 0.1%-0.3% by mass in a mist. The chitosan solution is prepared by dissolving chitosan in an aqueous solution of acetic acid with a volume fraction of 1%. The amount of spray is 2%-4% of the initial mass of the hawthorn raw material. Let it stand for 3-5 minutes. The degree of deacetylation in the chitosan solution is ≥90%.

8. The method for preparing hawthorn Liubao tea as described in claim 6, characterized in that, Maltodextrin with a glucose equivalent of 6-10 and a high DE value of 15-20 is selected and used in a mass ratio of 2:1-3:

1.

9. The method for preparing hawthorn Liubao tea as described in any one of claims 6-8, characterized in that, During the atmospheric pressure settling period after each vacuum permeation, a 0.2%-0.5% transglutaminase solution is sprayed evenly onto the surface of the hawthorn raw material in a mist form 2-3 minutes after the start of settling. The amount of spray is 1%-2% of the initial mass of the hawthorn raw material. Then, the settling continues until the total settling time reaches 5-8 minutes. After the third spraying and completion of vacuum penetration, and before the final baking process, place the hawthorn raw material in an environment with a temperature of 40-45℃ and a relative humidity of 55%-60% for 15-20 minutes, and gently turn it over once every 5 minutes at a speed of 20-30 revolutions per minute.

10. The method for preparing hawthorn Liubao tea as described in claim 9, characterized in that, When the hawthorn raw material is hawthorn blossoms, after the processed hawthorn raw material is mixed with the processed Liubao tea and placed in a constant temperature steam treatment, a flavor pre-curing treatment is also carried out, which specifically includes: After mixing the processed hawthorn raw materials with the processed Liubao tea at a mass ratio of 5:1, the mixture is placed in a sealed pressure vessel and subjected to 3-5 gradient pressure pulse cycles. Each cycle includes: pressurizing to 0.2-0.3 MPa and maintaining it for 1-2 minutes to allow the flavor components in the hawthorn raw materials to penetrate into the Liubao tea under pressure; then rapidly depressurizing to atmospheric pressure within 3-5 seconds; and allowing the mixture to stand at atmospheric pressure for 1-2 minutes between adjacent cycles to complete the gradient pressure pulse penetration. After gradient pressure pulse infiltration is completed, the mixture is placed in an ultrasonic oscillator at a frequency of 28-40 kHz and a power density of 0.3-0.5 W / cm³. 2 Under the conditions of 8-12 minutes; during the ultrasonic treatment, the temperature is increased from 25℃ to 35℃ at a rate of 2℃ every 2 minutes to complete the ultrasonic treatment; Two to three minutes before the end of the ultrasonic treatment, spray a tannin enzyme solution with a mass concentration of 0.1% to 0.3% onto the surface of the mixture in a mist-like manner. The amount of spraying is 1% to 2% of the total mass of the mixture to complete the flavor anchoring cross-linking. The flavor-anchored crosslinked mixture is placed in an environment with a temperature of 35-40℃ and a relative humidity of 35%-40% for pre-drying for 15-20 minutes until the overall moisture content of the mixture drops to 15%-18%. During the pre-drying process, the mixture is turned over every 5 minutes at a speed of 15-25 rpm to prevent the material surface from forming a crust. After the pre-drying is completed, it is then processed according to the constant temperature steam treatment and segmented baking process described in claim 1.

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