A health-preserving tea extraction process for directional enrichment of tea polyphenols

Abstract

This invention discloses a targeted enrichment extraction process for health-promoting tea containing tea polyphenols, belonging to the field of deep processing of tea and extraction technology of natural plant active ingredients. This process dynamically monitors the extraction process of compound health-promoting teas to obtain the changes in apparent total phenols, target ester-type catechins, and transformation-related markers. It identifies the early peak retreat window of ester-type catechins under the compensation of accompanying phenol release and terminates the main extraction prematurely when the window is triggered. The main extract is rapidly separated and cooled, and the solid residue is compensated for with a temperature lower than the main extraction temperature. Based on the ratio of target ester-type catechins to transformation-related markers in the compensated extract, selection and selective merging are performed to obtain a targeted enriched extract. This invention avoids the problem of structural changes in target ester-type catechins caused by continuous heating during traditional fixed-time extraction processes, improving the enrichment degree of target tea polyphenol components while maintaining a stable proportion of active components.

Description

Technical Field

[0001] This invention relates to the field of deep processing of tea and extraction of active ingredients from natural plants, and particularly to a health-preserving tea extraction process for the targeted enrichment of tea polyphenols. Background Technology

[0002] With the development of health-conscious consumption, health-promoting tea products with functional regulatory effects are gradually gaining attention. Health-promoting teas are typically blends of tea leaves with flowers, fruits, leaves, or rhizomes. Water extraction is used to extract tea polyphenols, catechins, flavonoids, and other plant active ingredients into the liquid phase. Among these, ester-type catechins, such as epigallocatechin gallate and epicatechin gallate, possess high bioactivity and are important components for evaluating the quality and functional value of tea polyphenols. However, during the extraction process of blended health-promoting teas, due to differences in the release rates of soluble phenolic substances, associated phenolic substances, and catechins from different plant materials, the changes in the components in the extract are not synchronous. This can easily lead to a situation where associated phenolic substances are continuously released while the target ester-type catechins have already reached their peak and begun to decline, making it difficult to accurately determine the appropriate termination time during extraction.

[0003] Currently, the extraction processes for health teas and tea polyphenols typically employ fixed temperatures and times, or determine the extraction endpoint based on changes in total phenol content. However, in actual extraction, while the total phenol content may continue to increase with rising extraction temperatures and extended extraction times, some target ester-type catechins are easily affected by heat, undergoing structural changes such as epimerization, hydrolysis, or oxidation. This results in the total phenol index failing to accurately reflect the retention status of the target active components. Furthermore, the subsequent release of associated phenolic substances from compound plant materials further increases the apparent total phenol content, making the traditional control method using the total phenol peak as the extraction endpoint prone to judgment lag. In addition, existing supplementary extraction methods often involve further high-temperature extraction of the solid residue, easily introducing low-value components that have already undergone transformation into the extract, leading to a decrease in the proportion of target ester-type catechins. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies, such as difficulty in accurately identifying the premature decay stage of ester-type catechins during the extraction of compound health teas, decreased structural integrity of target tea polyphenol components due to fixed extraction conditions, and insufficient selective control of characteristic components during the extraction process. Therefore, this invention proposes a health tea extraction process for the directional enrichment of tea polyphenols.

[0005] To address the problems existing in the prior art, the present invention adopts the following technical solution: S1. Mix the health tea raw materials containing tea leaves and compound plant raw materials with water, perform main extraction at the set extraction temperature, and obtain extract samples according to the preset sampling cycle. S2. The extract samples at different sampling points are tested to obtain the apparent total phenol equivalent concentration, the target ester catechin concentration, and the concentration of transformation-related markers. S3. Based on the changes in the equivalent concentration of apparent total phenols, the concentration of target ester catechins, and the concentration of transformation-related markers within adjacent sampling periods, identify the early peak retreat window of ester catechins under the compensation of continuous release of associated phenols, and stop the main extraction when the judgment conditions are met. S4. Separate the main extract from the solid residue, cool the first extract, and perform compensatory extraction on the solid residue under compensatory extraction conditions lower than the main extraction temperature. S5. Based on the ratio of target ester-type catechins to transformation-related markers in the compensation extract, the compensation extract is screened, and the compensation extract is combined with the first extract according to the predicted mixing and retention state to obtain a tea polyphenol-oriented enrichment extract.

[0006] Preferably, the total concentration T of the target ester-type catechins is determined according to the formula: in, To represent the molar concentration of gallic acid gallate, This refers to the concentration of epicatechin gallate.

[0007] Preferably, the total concentration M of the conversion-related biomarkers is determined according to the formula: in, This refers to the molar concentration of gallocatechin gallate. This refers to the molar concentration of catechin gallate. This represents the molar concentration of gallic acid.

[0008] Preferably, the criteria for determining the early peak retreat window include:

[0009]

[0010] in, This represents the change in the apparent total phenol equivalent concentration. This represents the change in the concentration of the target ester-type catechin. To convert the changes in the concentration of relevant biomarkers, , and These represent the repeatability standard deviations of the corresponding detection parameters.

[0011] Preferably, the repeatability standard deviation According to the formula: in, This is the result of the i-th parallel detection. To average the test results, This represents the number of parallel tests.

[0012] Preferably, the compensating extract is screened using the relative retention index R of ester-type catechins: in, , where T is the relative retention index of ester-type catechins, T is the total concentration of the target ester-type catechins, and M is the total concentration of conversion-related markers.

[0013] Preferably, the compensating extract satisfies: in, The relative retention index of ester-type catechins in the j-th compensating extract. This is the benchmark relative maintenance index corresponding to the early peak exit window.

[0014] Preferably, the mixing and holding state is predicted according to the formula: in, and The values ​​represent the total amount of the target ester-type catechins and the total amount of transformation-related markers in the first extract, respectively. and These represent the amounts of the corresponding substances in the j-th compensating extract.

[0015] Preferably, the tea polyphenol-enriched extract is concentrated under vacuum at low temperature, and the material temperature during the concentration process does not exceed 45°C.

[0016] Preferably, the concentrated tea polyphenol-directed enrichment extract is subjected to vacuum freeze-drying to obtain tea polyphenol-directed enrichment health tea powder.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a component identification mechanism based on dynamic changes during the extraction process. It simultaneously analyzes the release of apparent total phenols, changes in target ester-type catechins, and the accumulation of transformation-related markers during the extraction of compound health teas. It identifies a specific window for the premature decay of target ester-type catechins under conditions of continuous release of associated phenols, and terminates the main extraction process in a timely manner after this window is triggered. This avoids the problems of epimerization, hydrolysis, or oxidation of target ester-type catechins caused by prolonged heating in traditional fixed-time extraction methods. Through the above method, the extraction endpoint is transformed from traditionally relying on empirical parameter control to dynamic control based on the state changes of target active components, thereby improving the retention capacity and targeted enrichment effect of target tea polyphenol components.

[0018] 2. This invention addresses the problem of the continued release of associated phenols from compound plant raw materials, which affects the accuracy of total phenol evaluation. After the main extract is rapidly separated and cooled, a compensatory extraction method with a temperature lower than the main extraction temperature is used for the solid residue. The compensatory extract is then screened based on the ratio of target ester-type catechins to transformation-related markers. Finally, the compensatory extract is selectively merged by predicting the mixed retention state. This method can improve the utilization rate of residual effective components while reducing the entry of low-retention components into the final product, reducing the risk of further changes in active components during subsequent concentration, thereby achieving the targeted enrichment and stable retention of target tea polyphenol components during the extraction of health tea. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a flowchart of a health tea extraction process for the targeted enrichment of tea polyphenols. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to specific embodiments; it should be understood that the following embodiments are used to illustrate the technical concept, process steps, detection methods and parameter calculation methods of the present invention, and are not intended to limit the scope of protection of the present invention. The water described in this invention is purified water that meets the requirements for food processing; unless otherwise stated, the concentration is expressed as the actual concentration in the liquid phase after treatment, and the temperature is the material temperature.

[0021] Example: Figure 1 As shown, this invention provides a health tea extraction process for the targeted enrichment of tea polyphenols. In this embodiment, roasted green tea is used as the tea raw material, and chrysanthemum, hawthorn and mulberry leaves are used as plant compound raw materials. Among them, the dried capitulum of chrysanthemum is used, the pitted and dried fruit slices of hawthorn are used, and the dried leaves of mulberry leaves are used. The batch number of the roasted green tea is LC-01, with a moisture content of 6.8%; the batch number of the chrysanthemum is JH-01, with a moisture content of 8.2%; the batch number of the hawthorn is SZ-01, with a moisture content of 10.4%; and the batch number of the mulberry leaf is SY-01, with a moisture content of 7.5%. Each raw material is cleaned of foreign matter, dried at 45°C for 2 hours, pulverized, and passed through a 16-mesh sieve while retaining particles that cannot pass through a 30-mesh sieve, so that the particle size of each raw material is within the range of 16 to 30 mesh; the sieve is a sieve that meets the requirements of an industrial metal wire woven square hole sieve. The ultra-high performance liquid chromatography method described later was used to detect the epigallocatechin gallate, epicatechin gallate, gallocatechin gallate, catechin gallate and gallic acid in each raw material. The detection results are shown in Table 1. Table 1 Initial content of relevant components in each raw material

[0022] Plant-based compound raw materials can release phenolic acids, flavonoids, and other substances that can produce a total phenol color response; therefore, in this embodiment, the total phenol color result is defined as the apparent total phenol equivalent concentration, and is not directly equivalent to the content of structurally intact target ester-type catechins.

[0023] The main extraction equipment is a jacketed stainless steel extraction tank with a nominal volume of 30L and an effective working volume of 25L. The parts in contact with the material are made of food-grade 316L stainless steel. The main extraction tank is equipped with a paddle stirrer, a jacketed heating unit, a platinum resistance temperature sensor, a circulating sampling liquid path, and a bottom solid-liquid separation outlet; the stirrer speed can be adjusted within the range of 20 to 150 r / min; the circulating liquid path is driven by a food-grade peristaltic pump, and the circulation flow rate can be adjusted within the range of 0.5 to 3.0 L / min; The bottom solid-liquid separation outlet is connected to a bag filter with a pore size of 50μm; the filtered first extract enters a temporary storage tank through a plate heat exchanger. The compensation extraction uses an independent jacketed extraction tank with a nominal volume of 15L; the compensation extraction tank is set up separately from the first extract temporary storage tank to ensure that the separated first extract will not return and be heated together with the first solid residue; Vacuum concentration uses a low-temperature vacuum concentration tank with an effective volume of 30L. The concentration tank is equipped with a material temperature sensor, an absolute pressure sensor, a stirrer, and a sterile sampling port.

[0024] This embodiment uses the rapid micro-Folin-Ciocalteu colorimetric method to detect the equivalent concentration of apparent total phenols. ; Weigh gallic acid standard and prepare standard solutions with purified water at concentrations of 0 mg / L, 20 mg / L, 40 mg / L, 60 mg / L, 80 mg / L and 100 mg / L. Take 50 μL of standard solution or diluted test sample, add 250 μL of Folin-Ciocalteu reagent diluted 10 times with purified water, mix for 60 seconds, then add 200 μL of sodium carbonate solution with a mass concentration of 7.5%, react at 60℃ in the dark for 90 seconds, cool for 30 seconds, and measure the absorbance at 765 nm. A liquid sample of the same concentration without the addition of Folin-Ciocalteu reagent was used as the sample background, and the absorbance caused by the color and turbidity of the liquid sample itself was subtracted. With gallic acid concentration The x-axis represents absorbance after subtracting the background. Using the vertical axis as the ordinate, the resulting standard curve is:

[0025] The correlation coefficient is:

[0026] The apparent total phenol equivalent concentration of the liquid sample was calculated based on the standard curve and dilution factor, and expressed as milligram gallic acid equivalents per liter, with the unit being $extrm{mgGAE / L}$. The rapid colorimetric detection takes 2.2 minutes from sample collection to result output; all samples from the same batch use the same reagent batch, colorimetric temperature, colorimetric time, detection wavelength, and background subtraction method.

[0027] Epigallocatechin gallate, epicatechin gallate, gallocatechin gallate, catechin gallate and gallic acid were detected using a dual-channel ultra-high performance liquid chromatography system. The chromatographic column used was a C18 reversed-phase column with dimensions of 30 mm × 2.1 mm and a packing particle size of 1.7 μm; mobile phase A was a 0.1% (v / v) aqueous solution of formic acid, and mobile phase B was acetonitrile. The gradient elution procedure is as follows: From 0 to 0.15 minutes, the volume fraction of mobile phase B is maintained at 5%. Within 0.15–0.90 minutes, the volume fraction of mobile phase B increased linearly from 5% to 22%. Within 0.90–1.25 minutes, the volume fraction of mobile phase B increased linearly from 22% to 38%. Within 1.25–1.40 minutes, the volume fraction of mobile phase B decreased from 38% to 5%. 1.40–1.80 minutes, maintain the volume fraction of mobile phase B at 5% to reequilibrate the column; The flow rate was 0.80 mL / min, the column temperature was 35℃, the injection volume was 1 μL, and a diode array detector was used for detection at 280 nm. Under the above conditions, the retention times of gallic acid, epigallocatechin gallate, gallocatechin gallate, epigallocatechin gallate and catechin gallate were 0.30 min, 0.72 min, 0.91 min, 1.16 min and 1.34 min, respectively, and the resolution of adjacent peaks was not less than 1.50. Using the mass concentration of standard solutions The x-axis represents the area of ​​the chromatographic peaks. The standard curves for each component are shown in Table 2, with the vertical axis as the ordinate. Table 2 Standard curves for each component

[0028] The single chromatographic run time is 1.80 minutes, and the single sample detection cycle, including liquid sample pretreatment, injection, and data calculation, is 2.30 minutes. After obtaining the liquid sample from the circulating liquid circuit, the chromatographic detection sample was immediately placed in a 4°C cooling module, filtered through a hydrophilic filter membrane with a pore size of 0.22 μm, and the injection was completed within 5 minutes after sampling. Stability verification showed that when the liquid sample was stored at 4°C in the dark for 30 minutes, the changes in EGCG and ECG detection results compared to the immediate detection results did not exceed 1.2%. The mass concentration of each component is converted to molar concentration based on the corresponding molar mass; the molar concentrations of epigallocatechin gallate, epicatechin gallate, gallogallocatechin gallate, catechin gallate, and gallic acid are respectively denoted as... , , , and The unit is mmol / L; For the The total concentration of the target ester-type catechins at each sampling time point. Determined according to the following formula:

[0029] Total molar concentration of conversion-related markers Determined according to the following formula:

[0030] The total molar concentration of transformation-related markers is used to represent the combined detection quantity associated with changes in related components in the epimerization, hydrolysis, and compounding system of the target ester catechin, and does not indicate that all components are formed by the transformation of the target ester catechin according to stoichiometry.

[0031] For any liquid to be evaluated, the relative retention index of ester-type catechins Determined according to the following formula:

[0032] In the formula, The total molar concentration of the target ester-type catechins in the liquid to be evaluated. The total molar concentration of transformation-related markers in the liquid to be evaluated; For the first step in the main extraction process Each sampling time point:

[0033] For the Compensation extract:

[0034] For vacuum concentrates:

[0035] The relative retention index of ester-type catechins is a process control indicator used to represent the relative proportion of intact EGCG and ECG relative to selected transformation-related markers. It does not represent the absolute structural retention rate of EGCG and ECG across all transformation pathways.

[0036] Before determining the main extraction window, three parallel samples were obtained from a homogeneous liquid sample close to the expected window concentration level, and the apparent total phenol equivalent concentration, the total molar concentration of the target ester catechin, and the total molar concentration of transformation-related markers were measured respectively. For any detection parameter Sample standard deviation Determined according to the following formula:

[0037] In the formula, For the first The results of the parallel tests for The average value of the results of multiple parallel tests. In this embodiment, the number of parallel detections is [number]. ; Based on the results of each parallel test Value calculation, Based on the results of each parallel test The calculation of values ​​does not involve directly adding the standard deviations of each individual component.

[0038] To determine the effects of GCG, CG, and gallic acid released by the plant-based compound raw materials on... To mitigate the impact of plant-based compound raw materials, a blank control group was set up. The plant compound raw material blank group only added chrysanthemum, hawthorn and mulberry leaves, without adding roasted green tea; the mass ratio of chrysanthemum, hawthorn and mulberry leaves was the same as that of the formal compound group, and extraction was carried out according to the same material-liquid ratio, temperature, stirring and sampling conditions as in the example; Taking the corresponding time points of 15 minutes, 18 minutes and 21 minutes in Example 1 as examples, the test results of the formal compound group and the plant compound raw material blank group are shown in Table 3; Table 3. Background Release Validation Results of Plant Compound Raw Materials

[0039] During the 15-18 minute period, the formal compound group The concentration increased by 0.006 mmol / L, while the concentration in the plant compound raw material control group increased by 0.001 mmol / L. The background increase accounted for 16.67% of the increase in the formal compound group. During the 18-21 minute period, the formal compound group The increase was 0.007 mmol / L, and the increase in the plant compound raw material blank group was 0.001 mmol / L. The background increase accounted for 14.29% of the increase in the formal compound group. The results showed that, under the specific formulation and extraction conditions of this embodiment, the release of plant-based compound raw materials by themselves had an effect on... The increment contributed, but not near the window. The main source of the increase.

[0040] Two adjacent sampling time points constitute one sampling period; based on the detection results of adjacent sampling time points, calculate respectively:

[0041]

[0042]

[0043] When two consecutive sampling periods both satisfy:

[0044]

[0045]

[0046] Furthermore, when the relative retention index of ester-type catechins decreases continuously within two consecutive sampling periods, the sampling point corresponding to the next sampling period is determined as the trigger point for the early peak retreat window of ester-type catechins. ; Will The corresponding relative retention index of ester-type catechins was determined as the benchmark relative retention index. ; This indicates that the overall color signal is still increasing, or the decrease has not exceeded the detection repeatability fluctuation range; This indicates a decrease in the target ester-type catechin that exceeds the range of repeatable fluctuations; This indicates an increase in transformation-related biomarkers that exceeds the range of repeatability fluctuations.

[0047] use , and As a criterion for determining the amount of change, window identification was performed on 6 independent batches, and the results are shown in Table 4. Table 4. Window identification results at different standard deviation multiples

[0048] The results show that using When used as a judgment criterion, fluctuations in detection are easily misjudged as changes in components. There may be trigger delays or missed detections, while using... This approach can simultaneously address fluctuation detection and window triggering timeliness; therefore, this embodiment adopts... As a specific criterion for judgment; The results of comparing the initial screening thresholds of different compensated extracts and the predicted mixed liquid thresholds are shown in Table 5. Table 5 Comparison of different screening thresholds

[0049] This embodiment adopts As the initial screening threshold for the compensating extract, and using The above values ​​are used as the relative retention index thresholds for predicting the mixture and concentrate. These values ​​are process control settings for this embodiment and do not imply that they still have absolute critical significance after being removed from specific raw materials, equipment, and testing conditions.

[0050] This embodiment uses a rapid colorimetric detection module and two parallel ultra-high performance liquid chromatography detection channels; Liquid samples obtained at each sampling point are divided into comprehensive colorimetric detection subsamples and chromatographic detection subsamples; the comprehensive colorimetric detection subsamples are processed from sampling to output. The required time is 2.2 minutes from sample collection to output for chromatographic analysis. and The required time is 2.3 minutes, and the maximum detection delay for a single sampling point is 2.3 minutes. The system employs a dual-channel alternating sampling method, allowing the liquid sample from the previous sampling point to enter the other detection channel while the liquid sample from the next sampling point is being detected. The window trigger signal is generated by the controller based on the timestamped detection results; the 2-minute starting point for solid-liquid separation is the time when the controller outputs the window trigger signal, not the time when the liquid sample was initially acquired. In Example 1, the time required from obtaining the liquid sample at 21 minutes to the output window trigger signal was 2.3 minutes, and the time required from the output trigger signal to the completion of the main solid-liquid separation was 1.4 minutes. Window sampling time point The concentration was 0.462 mmol / L, which is the actual concentration in the first extract obtained after separation. The concentration was 0.458 mmol / L, and the relative change during the detection and execution delays was:

[0051] Window sampling time point The relative retention index of the first extract was 0.9059, while the actual relative retention index of the first extract was 0.9034. The difference between the two was 0.0025, indicating that the detection and execution delays did not cause the window control to fail.

[0052] Example 1: Raw material formulation and main extraction; Weigh out 1000g of the ingredients for the compound health tea, including 700g of roasted green tea, 100g of chrysanthemum, 100g of hawthorn and 100g of mulberry leaves; Based on the moisture content of each raw material, the dry weight of 1000g of the compound health tea raw materials is 926.3g; Add the compound health tea ingredients to the main extraction tank and add 16.0L of purified water, so that each 1g of compound health tea ingredients corresponds to 16mL of water; Start the agitator and set the agitation speed to 60 r / min; start the circulating liquid circuit and set the circulation flow rate to 1.5 L / min; heat the material to 78℃ at an average heating rate of 1.5℃ / min, and during the constant temperature period, the temperature control deviation shall not exceed ±0.5℃; The timing starts when the extract first reaches 78°C. Every 3 minutes, 18 mL of homogeneous liquid sample is taken from the circulating liquid path. Of this, 2 mL is used for rapid colorimetric detection, 4 mL is used for ultra-high performance liquid chromatography detection, and the remaining liquid sample is used for retesting. The taken liquid sample is not returned to the main extraction tank. A total of 144 mL of liquid sample was collected at 8 sampling points, accounting for 0.90% of the initial water volume.

[0053] Three parallel assays were performed on the same homogeneous liquid sample that was close to the expected window concentration level. The apparent total phenol equivalent concentrations were 331 mg GAE / L, 333 mg GAE / L, and 335 mg GAE / L, respectively. The calculated values ​​were:

[0054] The total molar concentrations of the target ester-type catechins were 0.449 mmol / L, 0.452 mmol / L, and 0.455 mmol / L, respectively. The calculations yielded:

[0055] The total molar concentrations of transformation-related markers were 0.045 mmol / L, 0.047 mmol / L, and 0.049 mmol / L, respectively. The calculations yielded:

[0056] Therefore, it is determined that:

[0057]

[0058]

[0059] The detection results of the main extraction process are shown in Table 6; Table 6. Dynamic detection results of main extraction in Example 1

[0060] Within a 15-18 minute sampling period:

[0061]

[0062]

[0063] satisfy:

[0064]

[0065]

[0066] and:

[0067] Within a sampling period of 18–21 minutes:

[0068]

[0069]

[0070] satisfy:

[0071]

[0072]

[0073] and:

[0074] The window triggering condition was met for two consecutive sampling periods, and the relative retention index of ester-type catechins decreased continuously; therefore, the 21-minute sampling point was determined as the window triggering point for the early peak retreat of ester-type catechins.

[0075] The benchmark relative retention index is:

[0076] The initial screening threshold for the compensating extract is:

[0077] The predicted thresholds for the mixture and concentrate are:

[0078] As shown in Table 6, during the period of 15–21 minutes, the apparent total phenol equivalent concentration increased from 320 mg GAE / L to 333 mg GAE / L, but the total molar concentration of the target ester catechin decreased from 0.482 mmol / L to 0.462 mmol / L. At the same time, the total molar concentration of conversion-related markers increased from 0.035 mmol / L to 0.048 mmol / L, forming a state in which the apparent total phenol signal continued to increase while the target ester catechin peak faded prematurely.

[0079] After the controller outputs a trigger signal, the jacket heating is immediately stopped and the bottom filter pipeline is turned on. Within 1.4 minutes after the trigger signal is output, the main liquid phase is discharged and the solid-liquid separation is completed to obtain the first extract and the first solid residue. The first extract is cooled by a plate heat exchanger, and its temperature drops from 77.6°C to 33.0°C within 3.8 minutes after solid-liquid separation is completed. It then enters a temporary storage tank. The first extract is not returned to the main extraction tank or the compensation extraction tank. First extract volume The target total molar concentration of ester-type catechins is 12.55 L. The concentration was 0.458 mmol / L, representing the total molar concentration of the conversion-related markers. It was 0.049 mmol / L; The relative retention index of ester-type catechins in the first extract is:

[0080] The total amount of the target ester-type catechins in the first extract is:

[0081] The total amount of substance of the transformation-related markers is:

[0082] The total amount of target ester-type catechins carried out by each sample during the main extraction stage is:

[0083] The total amount of transformation-related markers carried out in each sampling is:

[0084] When evaluating the overall recovery rate, the amount carried out by the above sampling should be included in the material balance; when merging the subsequent compensating liquids, the total amount of components actually retained in the first extract should be used as the basis. The wet weight of the first solid residue was 3.86 kg. A representative sample was dried at 105℃ to constant weight, and the moisture content of the first solid residue was measured to be 76.0%, with a dry weight of 0.926 kg, which corresponds to the dry weight of the initial raw material.

[0085] The first solid residue was transferred to a compensating extraction tank; the compensating extraction temperature was set to 60℃, which is 18℃ lower than the main extraction temperature, and the stirring speed was 60r / min. For the first compensation extraction, 5.0 mL of water was added per 1 g of the first solid residue (dry weight), for a total water volume of 4.63 L; for the second compensation extraction, 4.5 mL of water was added per 1 g of the first solid residue (dry weight), for a total water volume of 4.17 L; for the third compensation extraction, 4.0 mL of water was added per 1 g of the first solid residue (dry weight), for a total water volume of 3.71 L. Each compensation extraction lasted 4 minutes; after each compensation extraction, a 50μm bag filter was used for solid-liquid separation, and the filtration time was 1.5 minutes. The actual recovered volumes of the first, second, and third compensation extracts were 4.10L, 3.55L, and 3.05L, respectively; the unrecovered liquid consisted of liquid held in the filter media, liquid held in the pipeline, and residual liquid inside the solid residue. The test results of each compensating extract are shown in Table 7; Table 7. Detection results of the compensating extract in Example 1.

[0086] The first compensating extract satisfies:

[0087] The second compensating extract satisfies:

[0088] The third compensating extract satisfies:

[0089] Therefore, the first and second compensation extracts pass the initial screening, while the third compensation extract fails the initial screening and is not further merged for determination; the compensation extraction is terminated after the third compensation extraction is completed. Each compensating extract is immediately cooled to below 35°C after solid-liquid separation and stored separately, and is not returned to be heated together with the solid residue.

[0090] Before actual merging, the relative retention index is predicted based on the total amount of relevant components in the base liquid and the compensating extract to be merged; For base fluid:

[0091]

[0092] For the Parts of the compensating extract to be combined:

[0093]

[0094] The predicted relative retention index is:

[0095] Only if the predicted relative maintenance index meets the requirement The actual merger will only be executed at that time; The first extract was used as the base liquid for the initial merging determination; the predicted relative retention index after merging the first compensation extract was:

[0096] The calculation yielded:

[0097] because:

[0098] Therefore, the first compensating extract is combined with the first extract; The combined base liquid volume is:

[0099] The total amount of the target ester-type catechins after merging is:

[0100] The total amount of the combined transformation-related markers is:

[0101] The liquid obtained after merging the first compensating extract will be used as the base liquid for the next merging determination. The predicted relative retention index after the second compensating extract is:

[0102] The calculation yielded:

[0103] because:

[0104] Therefore, the second compensating extract is combined with the current base solution; The volume of the directional enrichment mixture after merging is:

[0105] The total amount of the target ester-type catechins is:

[0106] The total amount of substance of the transformation-related markers is:

[0107] The total molar concentration of the target ester-type catechins in the targeted enrichment mixture is:

[0108] The total molar concentration of transformation-related biomarkers is:

[0109] The relative retention index of ester-type catechins is:

[0110] The directional enrichment mixture is fed into a vacuum concentration tank; During the concentration process, the absolute pressure is controlled at 12-16 kPa, the material temperature is controlled at 42±2℃, and the stirring speed is 50 r / min; Based on the feed requirements for subsequent vacuum freeze drying, the target total molar concentration of ester-type catechins is preset to 1.20 mmol / L; During the concentration process, a 5 mL sample of the concentrate was taken every 10 minutes for testing. and And calculate After each sampling, the liquid volume and the amount of component substances are corrected. when Less than 1.20 mmol / L and Continue to condense; when Reaching 1.20 mmol / L and Concentration is terminated at the specified time; when The preset value has not yet been reached, but Stop heating and evaporation at this time; The vacuum concentration time was 78 minutes, and the final volume of the concentrate was 5.63 L; the following results were obtained:

[0111]

[0112] The relative retention index of ester-type catechins in the concentrate is:

[0113] satisfy:

[0114] The total amount of the target ester-type catechins after concentration is:

[0115] The retention rate, relative to the total amount of the target ester-type catechins before concentration, is:

[0116] This yields a health-preserving tea extract with targeted enrichment of tea polyphenols.

[0117] Example 2: Weigh 1000g of compound health tea ingredients, including 600g of roasted green tea, 150g of chrysanthemum, 150g of hawthorn and 100g of mulberry leaves; Add 12L of purified water so that each 1g of compound health tea raw material corresponds to 12mL of water; set the main extraction temperature to 70℃, with a temperature control deviation of no more than ±0.5℃, a stirring speed of 60r / min, and a circulation flow rate of 1.5L / min; Four sets of alternating ultra-high performance liquid chromatography detection channels are used to acquire a liquid sample every 1 minute; each detection channel completes the detection sequentially according to the liquid sample timestamp. The results obtained through parallel detection are as follows:

[0118]

[0119]

[0120] The corresponding judgment threshold is:

[0121]

[0122]

[0123] The test results after 20–23 minutes are shown in Table 8; Table 8 Detection results near the window in Example 2

[0124] A sampling period of 21-22 minutes satisfies:

[0125]

[0126]

[0127] and ; A sampling period of 22-23 minutes satisfies:

[0128]

[0129]

[0130] and ; therefore:

[0131]

[0132] Solid-liquid separation was completed 1.6 minutes after the window was triggered, and the first extract was cooled to 34°C within 4.2 minutes; The volume of the first extract was 9.40 L. It was 0.394 mmol / L. It was 0.040 mmol / L. It is 0.9078; The dry weight of the first solid residue is 0.918 kg; the compensation extraction temperature is set to 55℃, which is 15℃ lower than the main extraction temperature. For the first compensation extraction, 3.8 mL of water was added for every 1 g of the first solid residue (dry weight), the total water volume was 3.49 L, the extraction time was 3 minutes, and 3.20 L of the first compensation extract was recovered. For the second compensating extraction, 3.21 L of water was added, the extraction time was 3 minutes, and 2.80 L of the second compensating extract was recovered. The test results of the compensating extract are shown in Table 9; Table 9. Detection results of the compensation extract in Example 2

[0133] The initial screening threshold in this embodiment is:

[0134] The first compensation extract passed the initial screening, while the second compensation extract failed to pass the initial screening, therefore a third compensation extraction was not performed. The predicted relative retention index of the first compensating extract combined with the first extract is 0.9095, which is higher than:

[0135] Therefore, the first compensating extract is incorporated into the first extract.

[0136] The directional enrichment mixture was concentrated under vacuum at an absolute pressure of 14–18 kPa and a material temperature of 40 ± 2 °C. The target total concentration of ester-type catechins was preset to 0.95 mmol / L; after concentration to the preset concentration, the concentration was measured. It is 0.9052, which is higher than To obtain a health-preserving tea extract with targeted enrichment of tea polyphenols.

[0137] Example 3: Weigh 1000g of compound health tea ingredients, including 500g of roasted green tea, 150g of chrysanthemum, 150g of hawthorn, 100g of mulberry leaves, and 100g of other edible root and stem plant ingredients; Add 20L of purified water so that each 1g of compound health tea raw material corresponds to 20mL of water; set the main extraction temperature to 85℃, the stirring speed to 60r / min, and take a liquid sample every 3 minutes; The results obtained through parallel detection are as follows:

[0138]

[0139]

[0140] The detection results near the window are shown in Table 10; Table 10 Detection results near the window in Example 3

[0141] Both the 6-9 minute and 9-12 minute sampling periods satisfy the window triggering condition, therefore:

[0142]

[0143] Solid-liquid separation was completed 1.5 minutes after the window was triggered, and the first extract was cooled to 32°C. The volume of the first extract was 15.80 L. It was 0.495 mmol / L. It was 0.067 mmol / L; The first solid residue has a dry weight of 0.912 kg; the compensation extraction temperature is set to 60℃, which is 25℃ lower than the main extraction temperature, and the compensation extraction time is 6 minutes each time. The first, second, and third compensation extractions were performed with 6.38L, 5.47L, and 4.56L of water, respectively, and the actual recovered compensation extracts were 6.00L, 5.00L, and 4.00L. The test results of the compensating extract are shown in Table 11; Table 11 Detection results of the compensated extract in Example 3

[0144] The initial screening threshold in this embodiment is:

[0145] The first and second compensation extracts passed the initial screening, while the third compensation extract failed to pass the initial screening. The predicted relative retention index after combining the first compensation extract was 0.8848, and the predicted relative retention index after further combining the second compensation extract was 0.8798, both higher than:

[0146] Therefore, the first compensating extract and the second compensating extract are sequentially incorporated into the first extract; The total amount of the target ester-type catechins in the targeted enrichment mixture is:

[0147] The total amount of substance of the transformation-related markers is:

[0148] The relative retention index of ester-type catechins is:

[0149] Vacuum concentration is carried out under an absolute pressure of 12–16 kPa and a material temperature not exceeding 45°C. The target total concentration of ester-type catechins was preset to 1.50 mmol / L; when Reaching 1.50 mmol / L and Concentration was terminated when the concentration was not lower than 0.8389, resulting in a health-preserving tea extract with targeted enrichment of tea polyphenols.

[0150] Example 4: 5.00 L of the tea polyphenol-enriched health tea extract obtained in Example 1 was taken; its soluble solids content was 13.6%, the total concentration of the target ester-type catechins was 1.20 mmol / L, the total concentration of conversion-related markers was 0.132 mmol / L, and the relative retention index was 0.9009. The extract was placed in a freeze-drying tray with a thickness of 12 mm, and pre-frozen at -40°C for 4 hours. The completely frozen material is placed in a vacuum freeze dryer, and the absolute pressure in the drying chamber is reduced to 80 Pa. The shelf temperature in the first drying stage is -25°C for 16 hours. The shelf temperature in the second drying stage is 20°C and the absolute pressure is 50 Pa for 6 hours. After drying, the pressure was restored under nitrogen protection and the material was discharged to obtain 0.65 kg of tea polyphenol-enriched health tea powder. The powder was found to have a moisture content of 3.8% and a water activity of 0.23. The total amount of the target ester-type catechins before freeze-drying is:

[0151] After lyophilization, the powder was quantitatively reconstituted and analyzed. The total amount of the target ester-type catechins was 5.82 mmol, and the retention rate was:

[0152] The total amount of conversion-related markers after lyophilization was 0.65 mmol, and the relative retention index of ester-type catechins in the reconstituted solution was:

[0153] The change in the relative retention index of ester-type catechins before and after freeze-drying was 0.0014.

[0154] In the comparative example, the same raw materials, feed amount, water amount, main extraction temperature and stirring conditions as in Example 1 were used, but the extraction was not stopped according to the early peak exit window, but was continued to be extracted at 78°C for 30 minutes. At 30 minutes, the apparent total phenol equivalent concentration was 340 mg GAE / L, the total molar concentration of the target ester-type catechins was 0.420 mmol / L, and the total molar concentration of conversion-related markers was 0.075 mmol / L. The relative retention index is:

[0155] Compared to the window triggering point of Example 1, Comparative Example 1 has a higher apparent total phenol equivalent concentration, but a lower target ester catechin concentration and relative retention index.

[0156] Comparative Example 2 uses the same main extraction and window recognition steps as Example 1. After the window is triggered, the first extract is separated and cooled, but the first solid residue is not subjected to compensatory extraction. The total amount of the target ester-type catechin in the first extract obtained in Comparative Example 2 was 5.7479 mmol, and the relative retention index was 0.9034. In Example 1, after combining two qualified compensating extracts, the total amount of the target ester-type catechin was 6.8942 mmol, and the relative retention index was 0.9009. The increase ratio is: .

[0157] Comparative Example 3: Master extraction and window identification were performed according to the method of Example 1. After solid-liquid separation is completed, instead of using a plate heat exchanger for rapid cooling, it is naturally cooled in an environment of 25°C. It was found that it took 18 minutes for the first extract to cool from 77.6℃ to 35℃; the results of rapid cooling and natural cooling are shown in Table 12. Table 12 Comparison of different cooling methods

[0158] Comparative Example 4: The first solid residue was obtained according to the method of Example 1, using the same amount of water added and the compensated extraction time as in Example 1, but the compensated extraction temperature was set to 78°C; The results are shown in Table 13; Table 13 Comparison of different compensated extraction temperatures

[0159] The total amount of target ester-type catechins obtained by 78℃ compensated extraction was slightly higher, but the conversion-related markers increased, while the relative retention index decreased.

[0160] Comparative Example 5: The first extract and three compensating extracts were obtained according to the method of Example 1, without using... The initial screening and prediction merging rule is to directly add all three compensation extracts to the first extract; The total amount of the target ester-type catechins after direct merging is:

[0161] The total amount of substance of the transformation-related markers is:

[0162] The relative retention index is:

[0163] The results of selective merging and all direct merging are shown in Table 14; Table 14 Comparison of different merging methods

[0164] While direct merging increases the total amount of target ester catechins slightly, it also introduces more conversion-related markers, causing a decrease in the relative retention index and increasing the subsequent concentration load.

[0165] Examples 1 to 3 used main extraction temperatures of 70°C, 78°C and 85°C respectively, with material-to-liquid mass-to-volume ratios of 1:12, 1:16 and 1:20, and sampling intervals of 1 minute or 3 minutes. Each embodiment determines the early peak exit window by the continuous changes in the apparent total phenol equivalent concentration, the total molar concentration of the target ester catechin, the total molar concentration of transformation-related markers, and the relative retention index of ester catechin, rather than determining the main extraction endpoint solely based on a fixed time or the peak value of the apparent total phenol equivalent concentration. After the window is triggered, by stopping heating, rapidly separating solid and liquid and cooling the first extract, the target ester catechin that has been dissolved is no longer subjected to the subsequent high-temperature thermal process set up for extracting the internal components of the solid residue. The first solid residue was subjected to fractional compensation extraction with water at a temperature 15-25°C lower than the main extraction temperature, and the liquid phase was separated immediately after each compensation extraction. The compensation extract is first based on Initial screening is performed, and then the predicted relative retention index is calculated based on the volumes of the base solution and the compensating extract to be combined, the total molar concentration of the target ester-type catechins, and the total molar concentration of transformation-related markers. Only when the predicted relative retention index meets the following criteria will the combined index be considered valid. The actual merger will only be executed at that time; The directional enrichment mixture was concentrated under vacuum at a material temperature not exceeding 45°C, and... Under certain conditions, the target concentration is achieved, thereby obtaining a health-preserving tea extract with directional enrichment of tea polyphenols.

[0166] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A health-preserving tea extraction process for targeted enrichment of tea polyphenols, characterized in that, Includes the following steps: S1. Mix the health tea raw materials containing tea leaves and compound plant raw materials with water, perform main extraction at the set extraction temperature, and obtain extract samples according to the preset sampling cycle. S2. The extract samples at different sampling points are tested to obtain the apparent total phenol equivalent concentration, the target ester catechin concentration, and the concentration of transformation-related markers. S3. Based on the changes in the equivalent concentration of apparent total phenols, the concentration of target ester catechins, and the concentration of transformation-related markers within adjacent sampling periods, identify the early peak retreat window of ester catechins under the compensation of continuous release of associated phenols, and stop the main extraction when the judgment conditions are met. S4. Separate the main extract from the solid residue, cool the first extract, and perform compensatory extraction on the solid residue under compensatory extraction conditions lower than the main extraction temperature. S5. Based on the ratio of target ester-type catechins to transformation-related markers in the compensation extract, the compensation extract is screened, and the compensation extract is combined with the first extract according to the predicted mixing and retention state to obtain a tea polyphenol-oriented enrichment extract.

2. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, The target total concentration T of ester-type catechins is calculated according to the formula: in, To represent the molar concentration of gallic acid gallate, This refers to the concentration of epicatechin gallate.

3. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, The total concentration M of transformation-related biomarkers is calculated according to the formula: in, This refers to the molar concentration of gallocatechin gallate. This refers to the molar concentration of catechin gallate. This represents the molar concentration of gallic acid.

4. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, The criteria for determining the early peak retreat window include: in, This represents the change in the apparent total phenol equivalent concentration. This represents the change in the concentration of the target ester-type catechin. To convert the changes in the concentration of relevant biomarkers, , and These represent the repeatability standard deviations of the corresponding detection parameters.

5. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 4, characterized in that, Repeatability standard deviation According to the formula: in, This is the result of the i-th parallel detection. To average the test results, This represents the number of parallel tests.

6. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, Compensating extracts were screened using the relative retention index R of ester-type catechins: in, , where T is the relative retention index of ester-type catechins, T is the total concentration of the target ester-type catechins, and M is the total concentration of conversion-related markers.

7. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 6, characterized in that, The compensating extract satisfies: in, The relative retention index of ester-type catechins in the j-th compensating extract. This is the benchmark relative maintenance index corresponding to the early peak exit window.

8. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, The predicted mixed state is based on the formula: in, and The values ​​represent the total amount of the target ester-type catechins and the total amount of transformation-related markers in the first extract, respectively. and These represent the amounts of the corresponding substances in the j-th compensating extract.

9. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 1, characterized in that, The tea polyphenol-enriched extract was concentrated under vacuum at low temperature, with the material temperature not exceeding 45°C during the concentration process.

10. The extraction process for targeted enrichment of tea polyphenols in a health-preserving tea according to claim 9, characterized in that, The concentrated tea polyphenol-enriched extract was subjected to vacuum freeze-drying to obtain tea polyphenol-enriched health tea powder.

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