Black tea concentrated solution and preparation method thereof

Abstract

The invention discloses a black tea concentrated solution and a preparation method thereof. The black tea concentrated solution is obtained by performing flower and fruit mixing and aroma giving on tea raw materials, performing steam vortex aroma extraction, performing steam instantaneous explosion mass transfer treatment, performing steam turbine extraction, performing wall breaking, performing blending, performing high-pressure fusion, performing sterilization and performing filling. According to the method provided by the invention, the extraction efficiency and aroma quality of aroma substances of the tea leaves are improved by utilizing a steam vortex aroma extraction technology; the dissolution rate of effective components in the tea leaves and the content of functional substances are improved by utilizing steam instantaneous explosion mass transfer treatment and steam turbine extraction, and finally, black tea leaf wall-broken powder is added for blending and fusion, so that the produced black tea concentrated solution has the advantages of high flower and fruit aroma, fullness, rich flavor, bright soup color, mellow and rich taste and the like, and has relatively high nutritional and health-care values.

Description

Technical Field

[0001] The invention relates to the technical field of tea concentrate processing, in particular to a black tea concentrate and a preparation method thereof. Background Art

[0002] Tea concentrate refers to a liquid tea product made by removing a certain proportion of water from tea leaves through water extraction or squeezing fresh tea leaves with tea leaves as the main raw material. Tea concentrate can be widely used in the processing of food, beverages and other products because it is easy to use, easy to transport and store, and has the color, aroma, taste and other nutrients and flavor substances of tea, and has good application prospects.

[0003] New-style tea drinks are the third largest way to drink tea after hot drinks in cups and bottled tea drinks. They are loved by young consumers because of their natural health, fashionable design and rich flavors. New-style tea drinks pay more attention to product features, so the requirements for tea are quite different from those for traditional tea drinks and industrial drinks, which puts higher requirements on the characteristics and quality of raw materials. Only by understanding and grasping the tea requirements for new-style tea drinks can raw materials that meet market demand be produced, which requires breakthroughs in production technology for raw material suppliers.

[0004] The main process of black tea concentrate is extraction and concentration. At present, the black tea concentrate produced in industry generally uses static water as solvent, and dissolves the tea polyphenols, caffeine and other effective ingredients in black tea leaves, as well as the aroma substances in tea leaves, into water by soaking and infiltration. However, due to the static extraction, the contact between water and tea leaves is not sufficient and intense, resulting in slow dissolution of effective ingredients, uneven and insufficient extraction, long extraction time, and increased concentration time due to high tea-water ratio. In order to fully extract, high temperature is generally selected for the extraction of black tea in industry. However, due to the unique phenomenon of black tea after cooling, the black tea soup extracted at high temperature will produce precipitation due to the complexation of tea polyphenols, caffeine and other substances after cooling, so membrane concentration process cannot be used, and only vacuum concentration can be used. However, due to the technical limitations of high temperature and long time, vacuum concentration will cause the loss of tea polyphenols, caffeine, amino acids and other substances, as well as the oxidation and deterioration of volatile and non-volatile flavor components, resulting in problems such as bland taste, thin aroma, and bad flavor derivatives of the product. Compared with freshly brewed tea, it has no advantages, which seriously restricts the healthy development of the tea concentrate industry.

[0005] Therefore, solving a series of problems existing in the current production process of black tea concentrate and developing a high-quality black tea concentrate with rich aroma and flavor are of great significance to the development of the tea concentrate industry. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides an improved preparation method of black tea concentrated liquid and the black tea concentrated liquid.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In one aspect, the present invention provides a method for preparing a black tea concentrate, comprising the following steps:

[0009] (1) extracting aroma from black tea leaves using steam vortex aroma extraction technology to obtain aroma condensate;

[0010] (2) The black tea leaves are crushed, subjected to steam explosion treatment, and then subjected to steam turbine extraction to obtain an extract.

[0011] In some embodiments of the present invention, in order to verify the necessity of steam vortex aroma extraction and steam turbine extraction processes, comparative verification experiments were carried out, and the results showed that the steam vortex aroma extraction and steam turbine extraction steps in the preparation process are very necessary. The use of the steam vortex aroma extraction step can effectively improve the aroma of the black tea concentrate and make the taste of the tea concentrate richer; before the steam turbine extraction, the fiber structure of the tea leaves is broken by steam explosion treatment, which promotes the transformation and release of small molecules, and then the use of steam turbine extraction can further extract more active ingredients, making the taste of the tea concentrate more mellow and improving the quality of the tea concentrate. Reducing the steam vortex aroma extraction or steam turbine extraction steps in the preparation process will reduce the quality of the prepared tea concentrate in terms of aroma or taste. Therefore, the combined process of steam vortex aroma extraction and steam turbine extraction has significant advantages in improving the quality of black tea concentrate.

[0012] Furthermore, the steam vortex aroma extraction in step (1) comprises: placing black tea leaves in a steam vortex aroma extraction device, and introducing steam from bottom to top for aroma extraction.

[0013] The commonly used method for existing aroma extraction is distillation extraction. The tea aroma extract obtained by distillation extraction usually causes different degrees of deterioration of the tea aroma due to the long distillation time. At the same time, due to the high distillation temperature, some low-boiling point volatile substances in the tea aroma are lost during the heating process, causing the tea aroma in the final product to become weaker and worse.

[0014] The steam vortex aroma extraction process adopted in this application is to place black tea leaves in a vertical spiral turbine steam extractor, and the tea leaves are spirally laid thinly layer by layer in the extractor. Steam is passed into the equipment from bottom to top, vortexes and rises in the extractor, and contacts with the tea leaves in the extractor layer by layer to extract the aroma substances in the tea leaves. The collected steam is then condensed to obtain an aroma condensate. The steam vortex aroma extraction equipment can realize the variable temperature extraction of aroma by controlling the vacuum degree. At the same time, the rotation of the turbine can also realize the flip extraction of tea leaves, ensure the full contact between tea leaves and steam, and realize the high concentration enrichment of tea aroma.

[0015] The steam vortex aroma extraction technology increases the contact area and residence time between steam and tea. Compared with ordinary distillation extraction methods, it not only greatly enhances the extraction efficiency and enrichment concentration of tea aroma, but also can design steam extraction with different temperature gradients according to the characteristics of tea aroma substances to enrich aroma substances with different boiling points, making the obtained tea aroma substances richer and fuller, with a high degree of restoration.

[0016] In addition, aroma extraction and enrichment in the first step can also avoid the problem of aroma loss or deterioration due to subsequent high-temperature and long-term processing. At the same time, according to the quality requirements of the final product, aroma substances can be freely added to improve the aroma quality of the product and meet the needs of products of different qualities. This solves the problem of insufficient aroma and weak characteristic of the black tea concentrate produced by conventional processes.

[0017] Furthermore, the step (2) of crushing the black tea leaves for steam explosion treatment comprises: chopping the black tea leaves and placing them in a steam explosion machine for steam explosion treatment.

[0018] The steam explosion treatment is to cut the black tea leaves into pieces and place them in a steam explosion machine for steam explosion treatment, and then place them in a steam turbine extraction equipment for steam turbine extraction.

[0019] In view of the problem that the red concentrate produced by traditional industrial methods has a bland taste, the present invention creatively adopts steam instantaneous explosion mass transfer treatment technology. Due to the limitation of plant cell walls, traditional extraction methods are often difficult to fully extract the effective ingredients in cells. The osmotic effect of high-pressure steam is utilized to allow water vapor to quickly enter the tea tissue cells, and the pressure is released at the moment when the internal and external pressures are balanced, so that the tea leaves swell. The use of "steam explosion" to break the internal structure of tea leaves, destroy the tight connection between tea cellulose, and produce cracks and micropores on the surface of the cell wall can promote the release of small molecules, which can not only improve the dissolution rate and extraction effect of active ingredients such as tea polyphenols, flavonoids, and soluble sugars, but also use the conversion effect of steam explosion to increase the content of polysaccharides, amino acids, flavonoids and other substances in tea soup. At the same time, steam explosion increases the specific surface area of ​​steam and tea contact, improves the extraction efficiency, and can reduce the tea-water ratio to increase the concentration of the extract. In some embodiments, the necessity of steam instantaneous explosion treatment is also verified. After the steam explosion step is reduced after the steam vortex aroma extraction and before the steam turbine extraction, the content of active ingredients in the obtained tea concentrate is significantly reduced compared with the preparation process provided by the present invention, indicating that only by using the steam explosion technology provided by the present invention to perform tea explosion and then extraction can the quality of the black tea concentrate be optimized.

[0020] Furthermore, the steam turbine extraction in step (2) comprises: placing the black tea leaves after the steam explosion treatment in a steam turbine extraction device for steam turbine extraction.

[0021] In the existing production process of black tea concentrate, spray extraction or multi-stage countercurrent extraction is often used to obtain low-concentration tea soup, and then a certain amount of water is removed through a concentration process to obtain a high-concentration black tea concentrate. Due to the special turbidity phenomenon of black tea after cooling, the black tea soup extracted at high temperature cannot be used in the membrane concentration process due to membrane clogging, while the black tea soup extracted at low temperature cannot be widely used in high-end products because of its bland taste. Therefore, vacuum concentration is often used to concentrate black tea soup in industry. Vacuum concentration will cause oxidative browning of theaflavins and thearubigins in black tea, degradation of heat-sensitive substances such as tea polyphenols, and deterioration of the flavor of the tea soup, which seriously affects the quality of the product.

[0022] Aiming at the characteristics of black tea raw materials and the problem of flavor deterioration of black tea concentrate produced by traditional industrial methods, the present invention creatively adopts steam turbine extraction technology. Using a horizontal spiral turbine steam extractor, tea leaves are fed from one side to the other using a spiral conveyor. Tea leaves are separated into small cavities by a mesh turbine in the turbine steam extractor. Steam is radiated at multiple points on the inner wall of the drum, and tea soup flows out from the discharge port at the bottom. By utilizing the jet effect of the steam generator and multi-point mass transfer extraction, steam multi-stage dynamic mass transfer extraction is fully and efficiently realized, which not only improves the extraction strength and extraction area of ​​steam and tea leaves, but also shortens the extraction time, reduces the amount of steam used, and improves the extraction concentration. The horizontal spiral turbine steam extractor can realize variable temperature extraction of tea leaves by controlling the vacuum degree. At the same time, the tea leaves can be turned over and extracted by rotating the turbine, ensuring full contact between tea leaves and steam, and realizing high-concentration enrichment of tea flavor substances. After the extraction is completed, the steam is condensed into water by cooling, and the tea extract is collected by centrifugation. Compared with the traditional liquid water static liquid-mass exchange extraction method, steam turbine extraction technology not only saves time and improves efficiency, but also greatly reduces the time of subsequent concentration processing, improves product quality and reduces product costs.

[0023] Furthermore, the steam vortex aroma extraction equipment is a vertical spiral turbine steam extractor; and the steam turbine extraction equipment is a horizontal spiral turbine steam extraction machine.

[0024] Furthermore, the method further comprises step (3): breaking and crushing the tea residues after extraction to obtain tea residue broken-wall powder.

[0025] In some embodiments of the present invention, in order to enhance the taste level and flavor fullness of the product and realize the full utilization of tea leaves, the tea residues after extraction are fully utilized by utilizing the wall breaking process. According to the product application scenario and flavor requirements, the amount of tea residues added is adjusted to achieve the sublimation and enhancement of the overall flavor of the product, so that the product tastes full, rich, and layered, with distinct personality characteristics.

[0026] In some embodiments, a wall-breaking machine is used to break and crush the extracted tea residues, the speed of the wall-breaking machine is 10000-20000 r / min, the crushing time is 2-5 min, the particle size range is 2-10 μm, and the crushing temperature is 20-45° C.

[0027] Furthermore, the tea-gas ratio of the steam vortex aroma extraction in step (1) is 1:(3.5-5); and the tea-gas ratio of the steam turbine extraction in step (3) is 1:(3-8).

[0028] In some embodiments, the steam pressure of the steam vortex aroma extraction is 0.02-0.12 MPa, the steam temperature is 65-105° C., and the extracted tea vapor mass ratio is 1:(3.5-5).

[0029] In some embodiments, the steam pressure of the steam turbine extraction is 0.03-0.12 MPa, the extraction temperature is 70-105°C, the extraction time is 3-10 min, the extraction tea-steam ratio is 1:3-8, and sodium isoascorbate is added during the extraction process in an amount of 0.2-0.5% of the weight of the tea leaves.

[0030] Experiments have found that adding sodium isoascorbate during the steam turbine extraction process can effectively resist oxidation and improve the color and flavor of the tea soup.

[0031] Furthermore, the steam pressure of the steam explosion treatment in step (2) is 1.0 to 2.5 MPa, and the pressure maintenance time is 60 to 180 seconds.

[0032] In some embodiments, the tea leaves subjected to the steam explosion treatment have a specification of 1 mm to 5 mm.

[0033] Furthermore, the method also includes step (4): blending and high-pressure fusing the aroma condensate, the black tea extract and the tea residue broken wall powder; and before the steam vortex aroma extraction, the black tea leaves described in step (1) are subjected to the black tea aroma enhancement using the flower and fruit mixing aroma technology, wherein the aroma enhancers include one or more of lemongrass, rose, chrysanthemum, β-carotene, longan and honey.

[0034] In the preparation method of the black tea concentrate provided by the present invention, the step of mixing flowers and fruits to impart fragrance to the black tea raw materials before the steam vortex aroma extraction treatment is carried out, and the rich mesoporous structure of the tea leaves themselves is used as a channel for exogenous aroma substances to enter the interior of the tea leaves, and the purpose of enhancing the fragrance of the tea leaves themselves is achieved through mixing and adsorption with the exogenous aroma substances.

[0035] Mixing black tea aroma extract, black tea flavor extract and black tea wall-breaking powder not only improves the aroma height of the black tea concentrate, but also improves the product concentration of the black tea concentrate, and improves the aroma, flavor and tea charm of the product as a whole, making the product taste full and rich, rich in layers, rich in aroma and distinctive in characteristics. This process not only fully utilizes the whole tea leaves, but also maximizes the value of every part of the tea leaves. It is also an innovative invention for the production of modern black tea concentrate.

[0036] In some embodiments, the aroma material includes any one or more of lemongrass, rose, chrysanthemum, β-carotene, longan, and honey, and the added mass ratio of the aroma material is 1.0% to 10.0%.

[0037] In some embodiments, the aroma materials with floral and fruity aromas such as lemongrass, rose, and orchid are not subjected to baking treatment; while the aroma materials such as β-carotene, longan, and honey need to be baked.

[0038] In some embodiments, the aroma-imparting baking temperature is 130-180° C., and the baking method is far-infrared baking.

[0039] In some embodiments, the blending step is: blending tea aroma extract, high-concentration black tea extract, and black tea residue wall-broken powder in a certain proportion to obtain black tea concentrate.

[0040] Preferably, the mixing ratio of the tea aroma extract, the high-concentration black tea extract, and the black tea residue wall-broken powder is 1:(6-8):0.5.

[0041] In some embodiments, the high-pressure fusion refers to fusing the prepared black tea concentrate under high pressure to make the product have uniform texture and delicate taste.

[0042] Preferably, the high-pressure fusion process has a pressure of 40 to 80 MPa and fusion times of 6 to 10 times.

[0043] In some embodiments, the sterilization is high temperature transient sterilization (HTST) with a sterilization temperature of 135 to 150° C. and a time of 2 to 8 seconds.

[0044] In another aspect, the present invention provides a black tea concentrate prepared by the method described above.

[0045] The black tea concentrate prepared by the black tea concentrate preparation method provided by the present invention combines the tea aroma extraction with the tea flavor substance extraction process, and then mixes the tea residue wall-breaking powder, so that the produced black tea concentrate not only has the advantages of strong floral and fruity aroma, full and rich flavor, bright soup color, mellow and rich taste, etc., but also due to the application of innovative technology, compared with traditional products, the content of active substances such as soluble polysaccharides, dietary fiber, amino acids, flavonoids, theaflavins, polyphenols, etc. is high, and the nutritional and health value is relatively high.

[0046] The black tea concentrate prepared by the processing method of the present application has the characteristics of strong and rich floral and fruity aroma, bright soup color, mellow and rich taste, high content of active substances, and high nutritional and health value. It is understandable that the black tea concentrate provided by the present invention can not only be used to prepare new tea drinks, but also can be used for the production and processing of other tea-flavored products. The black tea concentrate provided by the present invention can also be further made into tea powder according to demand. For example, the black tea concentrate of the present invention can be made into instant black tea by freeze drying, spray drying, etc., while minimizing the influence on the aroma and taste.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The preparation method of the black tea concentrate provided by the present invention develops a steam vortex aroma extraction process, in which the steam forms a vortex in the flow from bottom to top, penetrates layers of spirally thin tea leaves, and increases the contact area and residence time between the steam and the tea leaves. The black tea aroma is extracted at a variable temperature by controlling the vacuum degree to enrich the aroma substances at different boiling points, and then the rotation of the turbine is used to ensure full contact between the tea leaves and the steam, so that the obtained tea aroma substances have high concentration, are full and rich, and have high reduction degree.

[0049] 2. The preparation method of the black tea concentrate provided by the present invention innovatively introduces the steam explosion treatment technology. "Steam explosion" can break the internal structure of tea leaves and promote the dissolution of polysaccharides, amino acids, flavonoids, polyphenols and other substances in tea leaves. At the same time, steam explosion increases the specific surface area of ​​contact between steam and tea leaves, improves the extraction efficiency, and can reduce the tea-water ratio to increase the concentration of the extract.

[0050] 3. The preparation method of the black tea concentrate provided by the present invention develops a steam turbine extraction process. By using a jet steam generator and multi-point mass transfer extraction, multi-stage dynamic steam extraction is realized, which not only improves the extraction strength and extraction area of ​​steam and tea, but also shortens the extraction time and reduces the amount of steam used. At the same time, according to the characteristics of the tea raw materials, variable temperature extraction is carried out, and the rotation of the turbine ensures that the tea leaves are fully in contact with the steam, so as to achieve high-concentration enrichment of tea flavor substances.

[0051] 4. In the processing method of the present invention, in order to enhance the taste level and flavor fullness of the product and realize the full-effect utilization of tea leaves, the tea residues after extraction are fully utilized by utilizing the wall breaking process. According to the product application scenario and flavor requirements, the amount of tea residues added is adjusted to achieve the sublimation and enhancement of the overall flavor of the product, so that the product tastes full, rich, and layered, with distinct personality characteristics.

[0052] 5. The present invention performs flower and fruit mixing to scent the tea raw materials, obtains aroma extract by steam vortex aroma extraction, obtains high-concentration tea soup extract by steam instant explosion treatment combined with steam turbine extraction process, and then performs wall-breaking treatment on tea residues to obtain ultrafine powder, and then mixes, high-pressure fuses, and sterilizes and fills the aroma extract, condensed extract, and ultrafine powder to finally obtain a black tea concentrate with high flower and fruit aroma, bright soup color, mellow and rich taste, and high content of active substances such as soluble polysaccharides, flavonoids, and polyphenols, and high nutritional and health value. At the same time, the first step is to extract and enrich the aroma, avoiding subsequent high-temperature and long-term processing, which causes the aroma to be lost or deteriorated. At the same time, according to the quality requirements of the final product, aroma substances can be freely added to improve the aroma quality of the product to meet the needs of products of different qualities, solving the problem that the aroma of the black tea concentrate produced by conventional processes is insufficient and the characteristic is not strong. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below through specific examples. It should be pointed out that the following examples are only used to further illustrate the present invention and should not be construed as limiting the present invention.

[0054] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0055] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0056] Example 1: Preparation method of black tea concentrate provided by the present invention

[0057] The processing method of the present application considers the entire production process of tea concentrate as a whole, innovates the tea juice extraction method, reduces the entire processing process, and especially according to the characteristics of the product used in the ready-mixed beverage industry, uses innovative technology to first enhance and protect the aroma, and then backfills the aroma and tea residue to supplement the aroma and taste of the product, so that the product can truly achieve a distinct characteristic flavor and a clear memory point, and truly utilizes process innovation to achieve product innovation. It should be noted that this process is not only suitable for the production of black tea concentrate, but also any other type of concentrated liquid products. According to the actual situation of the raw materials and the requirements of product characteristics, the process parameters can be improved or not improved to produce high-quality concentrated liquid products with the characteristics of the present invention.

[0058] The processing method of the black tea concentrate in this example includes the following steps in sequence: blending tea raw materials with flowers and fruits to impart fragrance, steam vortex aroma extraction, steam instantaneous explosion mass transfer treatment, steam turbine extraction, wall breaking, blending, high-pressure fusion, and sterilization and filling. The specific steps are as follows:

[0059] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0060] Steam vortex aroma extraction: Place the mixed Dianhong Gongfu black tea in a vertical spiral turbine aroma extractor, steam pressure: 0.025MPa, steam temperature: 65℃, extraction tea-steam ratio: 1:4, collect tea aroma extract.

[0061] Steam instantaneous explosion mass transfer treatment: After the aroma is extracted, the Dianhong Gongfu black tea is chopped and placed in a steam instantaneous explosion machine for instantaneous explosion treatment. The steam pressure is 1.5Mpa, the pressure maintenance time is 90s, and the tea leaf specification is 2.5mm.

[0062] Steam turbine extraction: Place the instantaneous explosion-treated Dianhong Gongfu black tea in a horizontal spiral turbine steam extractor and use dynamic steam to extract the tea. The steam pressure is 0.057Mpa, the extraction temperature is 85°C, the extraction time is 5min, and the extraction tea-steam ratio is 1:5. Sodium isoascorbate is added during the extraction process in an amount of 0.2% of the weight of the tea. After the extraction, the high-concentration black tea extract is collected.

[0063] Wall breaking: Put the Dianhong Gongfu black tea residue after steam turbine extraction into a wall breaking machine and break it into ultrafine powder. The speed of the wall breaking machine is 10,000 rpm, the breaking time is 3 min, the particle size is 5 μm, and the breaking temperature is 30°C to obtain the black tea residue wall-broken powder.

[0064] Preparation: Mix the black tea aroma extract, high-concentration black tea extract, and Dianhong Gongfu black tea dregs wall-breaking powder in a ratio of 1:7:0.5 to obtain black tea concentrate.

[0065] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 50MPa and the number of fusions is 6 times.

[0066] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 135°C, the processing time is 5 seconds, and the black tea concentrate is obtained by filling.

[0067] Example 2: Preparation method of black tea concentrate provided by the present invention

[0068] The processing method of the black tea concentrate in this example is the same as that in Example 1, and includes the following steps in sequence: blending tea raw materials with flowers and fruits to impart fragrance, steam vortex aroma extraction, steam instantaneous explosion mass transfer treatment, steam turbine extraction, wall breaking, blending, high-pressure fusion, and sterilization and filling. The specific steps are as follows:

[0069] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0070] Steam vortex aroma extraction: Place the mixed Dianhong Gongfu black tea in a vertical spiral turbine aroma extractor, steam pressure: 0.085MPa, steam temperature: 95℃, extraction tea-steam ratio: 1:5, collect tea aroma extract.

[0071] Steam instantaneous explosion mass transfer treatment: After the aroma is extracted, the Dianhong Gongfu black tea is chopped and placed in a steam instantaneous explosion machine for instantaneous explosion treatment. The steam pressure is 2.5Mpa, the pressure maintenance time is 160s, and the tea leaf specification is 5mm.

[0072] Steam turbine extraction: Place the instantaneous explosion treated Dianhong Gongfu black tea in a horizontal spiral turbine steam extractor and use dynamic steam to extract the tea leaves. Steam pressure: 0.121Mpa, extraction temperature: 105℃, extraction time: 3min, extraction tea-steam ratio 1:6. Sodium isoascorbate is added during the extraction process in an amount of 0.25% of the weight of the tea leaves. After the extraction, collect the high-concentration black tea extract.

[0073] Wall breaking: Put the Dianhong Gongfu black tea residue after steam turbine extraction into a wall breaking machine and break it into ultrafine powder. The speed of the wall breaking machine is 15,000 rpm, the breaking time is 2 min, the particle size range is 5 μm, and the breaking temperature is 35°C to obtain the black tea residue wall-broken powder.

[0074] Preparation: Mix the black tea aroma extract, high-concentration black tea extract, and Dianhong Gongfu black tea dregs wall-breaking powder in a ratio of 1:8:0.5 to obtain black tea concentrate.

[0075] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 80MPa and the number of fusions is 6 times.

[0076] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 140°C, the processing time is 3 seconds, and the black tea concentrate is obtained by filling.

[0077] Comparative Example 1: No Steam Vortex Aroma Extraction

[0078] Compared with Example 1, the processing method of the black tea concentrate in this example does not perform the steam vortex aroma extraction step, and includes the following steps in sequence: flower and fruit mixing and aromatization of tea raw materials, steam instantaneous explosion mass transfer treatment, steam turbine extraction, wall breaking, blending, high-pressure fusion, sterilization and filling. The specific steps are as follows:

[0079] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0080] Steam instantaneous explosion mass transfer treatment: After the aroma is extracted, the Dianhong Gongfu black tea is chopped and placed in a steam instantaneous explosion machine for instantaneous explosion treatment. The steam pressure is 1.5Mpa, the pressure maintenance time is 100s, and the tea leaf specification is 3mm.

[0081] Steam turbine extraction: Place the instantaneous explosion-treated Dianhong Gongfu black tea in a horizontal spiral turbine steam extractor and use dynamic steam to extract the tea. Steam pressure: 0.047Mpa, extraction temperature: 80℃, extraction time: 8min, extraction tea-steam ratio 1:8. Sodium isoascorbate is added during the extraction process, and the added amount is 0.5% of the weight of the tea. After the extraction, collect the high-concentration black tea extract.

[0082] Wall breaking: Put the Dianhong Gongfu black tea residue after steam turbine extraction into a wall breaking machine and break it into ultrafine powder. The speed of the wall breaking machine is 12000 rpm, the breaking time is 2 min, the particle size range is 4μm, the breaking temperature is 25°C, and the black tea residue wall-broken powder is obtained.

[0083] Preparation: High-concentration black tea extract and Dianhong Gongfu black tea dregs wall-breaking powder are mixed in a ratio of 1:7:0.5 to obtain black tea concentrate.

[0084] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 50MPa and the number of fusions is 6 times.

[0085] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 135°C, the processing time is 5 seconds, and the black tea concentrate is obtained by filling.

[0086] Comparative Example 2: No steam explosion mass transfer treatment step

[0087] Compared with Example 1, the processing method of the black tea concentrate in this example does not perform the steam instantaneous explosion mass transfer extraction step, and includes the following steps in sequence: flower and fruit mixing and aromatization of tea raw materials, steam vortex aroma extraction, steam turbine extraction, wall breaking, blending, high-pressure fusion, and sterilization and filling. The specific steps are as follows:

[0088] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0089] Steam vortex aroma extraction: Place the mixed Dianhong Gongfu black tea in a vertical spiral turbine aroma extractor, steam pressure: 0.047MPa, steam temperature: 80℃, extraction tea-steam ratio: 1:4.0, collect the tea aroma extract.

[0090] Steam turbine extraction: Place the instant-explosion treated Dianhong Gongfu black tea in a horizontal spiral turbine steam extractor and use steam to dynamically extract the tea leaves. Steam pressure: 0.047Mpa, extraction temperature: 80°C, extraction time: 5min, extraction tea-steam ratio 1:4, add sodium isoascorbate during the extraction process, the addition amount is 0.35% of the weight of the tea leaves, and collect the high-concentration black tea extract after the extraction.

[0091] Wall breaking: Put the Dianhong Gongfu black tea residue after steam turbine extraction into a wall breaking machine and break it into ultrafine powder. The speed of the wall breaking machine is 20,000 rpm, the breaking time is 2 min, the particle size range is 5 μm, and the breaking temperature is 45°C to obtain the black tea residue wall-broken powder.

[0092] Preparation: Mix the black tea aroma extract, high-concentration black tea extract, and Dianhong Gongfu black tea dregs wall-breaking powder in a ratio of 1:8:0.5 to obtain black tea concentrate.

[0093] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 70MPa and the number of fusions is 10 times.

[0094] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 140°C, the processing time is 3 seconds, and the black tea concentrate is obtained by filling.

[0095] Comparative Example 3: No steam turbine extraction step

[0096] Compared with Example 1, the processing method of the black tea concentrate in this example replaces the steam turbine extraction step with a commonly used spray extraction process, and includes the following steps in sequence: flower and fruit mixing and aromatization of tea raw materials, steam vortex aroma extraction, steam instantaneous explosion mass transfer treatment, hot water spray extraction, wall breaking, blending, high-pressure fusion, sterilization and filling. The specific steps are as follows:

[0097] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0098] Steam vortex aroma extraction: Place the mixed Dianhong Gongfu black tea in a vertical spiral turbine aroma extractor, steam pressure: 0.038MPa, steam temperature: 75℃, extraction tea-steam ratio: 1:3.5, collect the tea aroma extract.

[0099] Steam instantaneous explosion mass transfer treatment: After the aroma is extracted, the Dianhong Gongfu black tea is chopped and placed in a steam instantaneous explosion machine for instantaneous explosion treatment. The steam pressure is 2.5Mpa, the pressure maintenance time is 180s, and the tea leaf specification is 1mm.

[0100] Spray extraction: Place the instant-explosion treated Dianhong Gongfu black tea in a spray pot and use hot water to extract the tea leaves. The water temperature is 85°C, the extraction time is 10 minutes, and the extraction tea-water ratio is 1:8. Sodium isoascorbate is added during the extraction process, and the added amount is 0.25% of the weight of the tea leaves. Collect the black tea extract after the extraction.

[0101] Wall breaking: Put the Dianhong Gongfu black tea residue after steam turbine extraction into a wall breaking machine and break it into ultrafine powder. The speed of the wall breaking machine is 10,000 rpm, the breaking time is 5 min, the particle size range is 4 μm, and the breaking temperature is 40°C to obtain the black tea residue wall-broken powder.

[0102] Preparation: Mix the tea aroma extract, black tea extract and Dianhong Gongfu black tea dregs wall-breaking powder in a ratio of 1:8:0.5 to obtain black tea concentrate.

[0103] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 50MPa and the number of fusions is 8 times.

[0104] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 138°C, the processing time is 6 seconds, and the black tea concentrate is obtained by filling.

[0105] Comparative Example 4: No wall breaking step

[0106] Compared with Example 1, the processing method of the black tea concentrate in this example removes the wall breaking step and includes the following steps in sequence: flower and fruit mixing and aromatization of tea raw materials, steam vortex aroma extraction, steam instantaneous explosion mass transfer treatment, steam turbine extraction, blending, high-pressure fusion, and sterilization and filling. The specific steps are as follows:

[0107] Mix tea leaves, flowers and fruits to add fragrance: Choose Dianhong Gongfu black tea, add 3.0% of a mixture of lemongrass and roses, lemongrass: rose = 3:7, and mix well.

[0108] Steam vortex aroma extraction: Place the mixed Dianhong Gongfu black tea in a vertical spiral turbine aroma extractor, steam pressure: 0.085MPa, steam temperature: 95℃, extraction tea-steam ratio: 1:4, collect tea aroma extract.

[0109] Steam instantaneous explosion mass transfer treatment: After the aroma is extracted, the Dianhong Gongfu black tea is chopped and placed in a steam instantaneous explosion machine for instantaneous explosion treatment. The steam pressure is 2.5Mpa, the pressure maintenance time is 150s, and the tea leaf specification is 5mm.

[0110] Steam turbine extraction: Place the instantaneous explosion treated Dianhong Gongfu black tea in a horizontal spiral turbine steam extractor and use steam to extract the tea leaves. Steam pressure: 0.121Mpa, extraction temperature: 105℃, extraction time: 3min, extraction tea-steam ratio 1:5. Sodium isoascorbate is added during the extraction process in an amount of 0.2-0.5% of the weight of the tea leaves. After the extraction, collect the high-concentration black tea extract.

[0111] Preparation: Mix the tea aroma extract and high-concentration black tea extract in a ratio of 1:7 to obtain black tea concentrate.

[0112] High-pressure fusion: The black tea concentrate is subjected to high-pressure fusion to make the product have uniform texture and smooth taste. The fusion pressure is 60MPa and the number of fusions is 6 times.

[0113] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 135°C, the processing time is 3 seconds, and the black tea concentrate is obtained by filling.

[0114] Comparative Example 5: Conventional Processing Method

[0115] In this example, the black tea concentrate is processed according to the conventional method, which includes the following steps in sequence: tea raw materials, hot water spray extraction, centrifugation, vacuum concentration, sterilization and filling. The specific steps are as follows:

[0116] Tea raw materials: choose Dianhong Gongfu black tea, tea specifications: 3mm.

[0117] Hot water spray extraction: Place the Dianhong Gongfu black tea in a spray pot and use hot water to extract the tea leaves. The extraction temperature is 90°C, the extraction time is 25 minutes, and the extraction tea-water ratio is 1:12. Sodium isoascorbate is added during the extraction process, and the added amount is 0.2% of the weight of the tea leaves. Collect the black tea extract after the extraction is completed.

[0118] Centrifugation: The black tea extract was centrifuged in a disc centrifuge with a centrifugal flow rate of 3.5 T / hr.

[0119] Vacuum concentration: The black tea centrifuge liquid is vacuum concentrated, and the concentration at the end of concentration is 20.0%.

[0120] Sterilization and filling: high temperature transient sterilization (HTST) is used, the processing temperature is 135°C, the processing time is 5 seconds, and the black tea concentrate is obtained by filling.

[0121] Quality Analysis of Black Tea Concentrate

[0122] Take the black tea concentrate produced in the above examples 1 to 2, the black tea concentrate produced in comparative examples 1-5, and the black tea leaves (freshly brewed tea) made by mixing flowers and fruits for fragrance in the examples and make soup in the same proportion for sensory evaluation. Specifically, the black tea concentrate made in each example is diluted with 80°C hot water to a tea soup with a concentration of 0.5% according to the product concentration, and then the Yunnan Hong Gongfu black tea leaves made by mixing flowers and fruits for fragrance are brewed with 95°C boiling water at a tea-water ratio of 1:15, and then diluted to a tea soup with a concentration of 0.5%. Then use the black tea concentrate produced in the above examples 1 to 2, the black tea concentrate produced in comparative examples 1-5, and the black tea leaves made by mixing flowers and fruits for fragrance in the examples to brew tea juice with 95°C boiling water at a tea-water ratio of 1:15, and make application samples according to the SOP of light milk tea products and lemon black tea products in the new tea beverage industry.

[0123] 10 R&D personnel who have been working in the tea industry for more than 5 years and 10 R&D personnel who have been working in the new tea beverage industry for more than 5 years were selected to visually observe the tea soup color, smell the aroma, and taste the tea soup. The specific scoring criteria are shown in Table 1. Then, according to the 10-point scoring rule, the 8 tea soups were comprehensively scored according to the soup color accounting for 15%, the aroma accounting for 35%, and the taste accounting for 50%, and the average score was calculated. The sensory evaluation and scoring results of the diluted tea soup samples and application samples are shown in Table 2.

[0124] Table 1 Sensory evaluation standards

[0125]

[0126]

[0127] Table 2 Sensory evaluation and scoring results of tea dilution samples and application samples

[0128]

[0129] The sensory evaluation results in Table 2 show that the black tea concentrate produced in Examples 1 and 2 has the characteristics of high and full characteristic fragrance, fresh and refreshing taste, and bright red soup color. The light milk tea prepared with the black tea concentrate produced in Examples 1 and 2 has bright yellow milk color and thick and full taste. The prepared lemon tea has fresh aroma, mellow taste, and is not sour or astringent. However, since Comparative Examples 1 to 5 do not use the complete innovative method proposed by the present invention, the products show some defects in aroma or taste, so the performance in the product is not perfect. Although the comparative brewed tea is fresh and freshly brewed, it lacks the coordination and supplement of aroma and taste due to the limitations of the brewing equipment and technology. The sensory evaluation and score are not as good as Examples 1 and 2.

[0130] In addition, the black tea concentrate produced in the above-mentioned Examples 1-2 and the black tea concentrate produced in Comparative Examples 1-5 were diluted into tea soup with a concentration of 0.5%, and physical and chemical indexes were tested. Among them, the tea polyphenol content was determined by the detection method of tea polyphenols in tea beverages in Appendix A of GB / T 21733 tea beverages; the caffeine content was determined by GB 5009.139; the amino acid was determined by GB / T 8314-2013; the polysaccharide was determined by the second method in GB / T 5009.8-2023; the cellulose was determined by GB 5009.88-2023; the flavonoids were determined by NY / T3950-2021; and theaflavins were determined by GB / T 30483-2013. The extraction yield is the product of the output and concentration of the black tea concentrate, divided by the amount of tea added. The results of the physical and chemical indexes of the tea soup are shown in Table 3.

[0131] Table 3 Test results of physical and chemical indexes of tea soup

[0132]

[0133] The test results of physical and chemical indicators in Table 3 show that the test results of various indicators of the black tea concentrate produced in Examples 1 and 2 are much higher than those of the black tea concentrate produced by the conventional method in Comparative Example 5. By comparing Examples 1 and 2 with Comparative Examples 1-5, it can be seen that the quality of the black tea concentrate produced is reduced by reducing the steam vortex aroma extraction or steam instantaneous explosion mass transfer treatment or steam turbine extraction or wall breaking treatment in the production process, indicating that the effective ingredients in the black tea leaves cannot be effectively extracted without one of the steps of the preparation method provided by the present invention, and the steam vortex aroma extraction, steam instantaneous explosion mass transfer treatment, steam turbine extraction and wall breaking process are indispensable in improving the aroma concentration and dissolution of the effective ingredients in the black tea concentrate. At the same time, the test results of the conventional process are compared to verify that the black tea concentrate produced by the innovative process proposed by the present invention has the characteristics of high content of nutritional and health functional factors such as tea polyphenols, caffeine, amino acids, soluble polysaccharides, flavonoids, dietary fiber, and theaflavins.

[0134] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for preparing a black tea concentrate, characterized in that: The following steps are involved: (1) extracting aroma from black tea leaves using a steam vortex aroma extraction process to obtain aroma condensate; (2) The black tea leaves are crushed, subjected to steam explosion treatment, and then subjected to steam turbine extraction to obtain an extract.

2. The method according to claim 1, characterized in that The steam vortex aroma extraction in step (1) comprises: placing black tea leaves in a steam vortex aroma extraction device, and introducing steam from bottom to top to extract the aroma.

3. The method according to claim 1, characterized in that The step (2) of crushing the black tea leaves and subjecting them to steam explosion treatment comprises: chopping the black tea leaves and placing them in a steam explosion machine for steam explosion treatment.

4. The method according to claim 1, characterized in that The steam turbine extraction in step (2) comprises: placing the black tea leaves after steam explosion treatment in a steam turbine extraction device for steam turbine extraction.

5. The method according to claim 2, characterized in that The steam vortex aroma extraction equipment is a vertical spiral turbine aroma extraction machine; the steam turbine extraction equipment is a horizontal spiral turbine steam extraction machine.

6. The method according to claim 1, characterized in that The method further comprises step (3): breaking and crushing the extracted black tea residues to obtain black tea residue broken-wall powder.

7. The method according to claim 1, characterized in that The tea-gas ratio of the steam vortex aroma extraction process in step (1) is 1:3.5-5; the tea-gas ratio of the steam turbine extraction in step (2) is 1:(3-8).

8. The method according to claim 1, characterized in that The steam pressure of the steam explosion treatment in step (2) is 1.0 to 2.5 MPa, and the pressure maintenance time is 60 to 180 seconds.

9. The method according to claim 6, characterized in that The method further comprises the step (4): mixing and high-pressure fusing the aroma condensate, the black tea extract and the tea residue wall-breaking powder; and the black tea leaves described in the step (1) are subjected to the black tea aroma enhancement by using the flower and fruit mixing aroma enhancement technology before the steam vortex aroma extraction, wherein the aroma enhancement material comprises one or more of lemongrass, rose, chrysanthemum, β-carotene, longan and honey.

10. A black tea concentrate, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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