Fresh cutting-enzyme deactivation-color protection synergistic treatment process for stem medicinal materials

Abstract

The invention relates to a stem medicinal material fresh cutting-enzyme deactivation-color protection synergistic treatment process, and relates to the technical field of traditional Chinese medicinal material processing, and the stem medicinal material fresh cutting-enzyme deactivation-color protection synergistic treatment process comprises the following steps: S1, performing fresh cutting on stem medicinal materials to obtain fresh-cut medicinal materials; s2, immersing the fresh-cut medicinal materials into a composite natural extract treating fluid, wherein the composite natural extract treating fluid comprises at least one natural polyphenol antioxidant compound, at least one natural organic acid or enzyme activity regulator and a solvent; s3, ultrasonic treatment and microwave treatment are simultaneously or sequentially applied to the fresh-cut medicinal materials immersed in the composite natural extract treating fluid, and synergistic enzyme deactivation and color protection are carried out; and S4, draining the fresh-cut medicinal materials subjected to the synergistic enzyme deactivation and color protection treatment, and then performing drying treatment until the preset moisture content is reached. Through the multiple effects of the composite natural extract and the synergistic interaction of the ultrasonic-microwave physical field, the color stability, the enzyme activity inhibition degree and the effective component retention rate of the processed medicinal materials are comprehensively improved.

Description

Technical Field

[0001] This application relates to the field of traditional Chinese medicine processing technology, and in particular to a synergistic processing technology for fresh-cutting, enzyme-inactivating, and color-protecting stem medicinal materials. Background Technology

[0002] Stem-based medicinal herbs hold an important place in traditional Chinese medicine, and their initial processing at the place of origin after fresh cutting is a crucial step in ensuring the quality of the herbs and maximizing their medicinal value. However, existing initial processing techniques for fresh-cut stem-based medicinal herbs generally have some insurmountable defects, which directly affect the final quality and application of the medicinal materials.

[0003] Currently, during the processing of many fresh-cut stem medicinal materials, mechanical damage to the tissue cells activates endogenous enzymes (such as polyphenol oxidase and peroxidase), which then come into contact with phenolic substrates, easily leading to enzymatic browning reactions. This is accompanied by non-enzymatic oxidation, causing the medicinal materials to rapidly darken and become dull, deviating significantly from their natural color. This not only affects the appearance and commercial value of the medicinal materials but may also indicate internal quality deterioration. Existing technologies are often insufficient to effectively inhibit this rapid color deterioration and fail to achieve ideal color protection.

[0004] Regarding enzyme activity issues, traditional enzyme inactivation methods, such as simple hot water blanching or prolonged drying, often suffer from incomplete enzyme inactivation, excessively long processing times, or excessively high temperatures. These methods not only fail to ensure complete and uniform enzyme inactivation but may also cause unnecessary damage to the matrix and active ingredients of the medicinal material due to excessive heat treatment or lengthy processing cycles. It is difficult to achieve a good balance between efficient enzyme inactivation and maintaining the overall quality of the medicinal material, thus affecting its intrinsic quality.

[0005] More importantly, many stem-based medicinal herbs contain characteristic medicinal components, such as certain saponins, flavonoids, and alkaloids, which are often sensitive to environmental factors such as light, heat, and oxygen. In existing primary processing methods, due to a lack of effective protective measures or improper control of process conditions, these precious medicinal components are easily degraded, oxidized, or lost, significantly reducing the medicinal value and clinical efficacy of the herbs and preventing the full preservation of their intrinsic essence.

[0006] In summary, existing primary processing technologies for fresh-cut stem medicinal materials have significant shortcomings in maintaining the color of the materials, completely inactivating endogenous enzymes, effectively protecting the active ingredients, and achieving high efficiency, stability, and ease of large-scale application. Therefore, there is an urgent need to develop a new technology that can synergistically address these issues and comprehensively improve the quality and efficiency of primary processing of fresh-cut stem medicinal materials to meet the demands of the modern Chinese medicine industry for high-quality raw materials. Summary of the Invention

[0007] The purpose of this application is to provide a synergistic processing technology for fresh-cut stem medicinal materials, which combines enzyme inactivation and color protection. This technology solves the technical problems commonly found in existing primary processing techniques for fresh-cut stem medicinal materials, such as severe color deterioration, incomplete inactivation of endogenous enzymes, and significant loss of medicinal components.

[0008] The synergistic processing technology for fresh-cutting, enzyme-inactivating, and color-protecting of stem medicinal materials provided in this application includes the following steps: S1. Freshly cut the stems of medicinal herbs to obtain freshly cut medicinal herbs; S2. Immerse the fresh-cut medicinal materials in a compound natural extract treatment solution, wherein the compound natural extract treatment solution contains at least one natural polyphenol antioxidant complex, at least one natural organic acid or enzyme activity regulator, and a solvent. S3. The fresh-cut medicinal materials immersed in the compound natural extract treatment solution are simultaneously or sequentially subjected to ultrasonic treatment and microwave treatment to achieve synergistic enzyme inactivation and color protection. S4. Drain the fresh-cut medicinal materials that have undergone synergistic enzyme inactivation and color protection treatment, and then dry them until the preset moisture content is reached.

[0009] Preferably, the natural polyphenol antioxidant complex in the compound natural extract treatment solution in step S2 is selected from one or more of green tea extract, bamboo leaf extract, rosemary extract, and grape seed extract, and its total polyphenol mass concentration in the treatment solution is 0.2-2.0%.

[0010] Preferably, the natural organic acid or enzyme activity regulator in the compound natural extract treatment solution in step S2 is selected from one or more combinations of citric acid, L-ascorbic acid, L-ascorbyl palmitate, and phytic acid, and its total mass concentration in the treatment solution is 0.1-1.5%, and the pH value of the treatment solution is adjusted to the range of 3.5-5.5.

[0011] Preferably, the composite natural extract treatment solution in step S2 further contains a natural penetration enhancer or film-forming agent, selected from one or more combinations of tea saponin extract, soapberry saponin extract, low molecular weight chitosan, and sodium alginate, with a total mass concentration of 0.01-0.5% in the treatment solution.

[0012] Preferably, the ultrasonic treatment in step S3 operates at a frequency of 20-60kHz, a power density of 50-300W / L, and a duration of 2-10 minutes.

[0013] Preferably, the microwave treatment in step S3 raises the temperature of the treatment liquid and fresh-cut medicinal materials to the target enzyme-inactivating temperature of 50-75°C within 2-8 minutes, and maintains this temperature for 2-10 minutes.

[0014] Preferably, the ultrasonic treatment and microwave treatment in step S3 are performed simultaneously, or the ultrasonic pretreatment is followed by microwave treatment, or the two are performed alternately.

[0015] Preferably, the total combined processing time for ultrasonic treatment and microwave treatment in step S3 is 3-20 minutes.

[0016] Preferably, in step S1, the thickness of the freshly cut medicinal material is 2.0-10.0 mm or the segment length is 1.0-5.0 cm.

[0017] Preferably, the immersion time in the treatment solution in step S2 is controlled within 2-10 minutes.

[0018] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention pretreats fresh-cut stem medicinal materials using a composite natural extract composed of specific components, and combines this with the synergistic enhancement effect of ultrasound and microwave physical fields to significantly improve the color-protecting effect of the medicinal materials. This organic combination of chemical protection and physical field promotion effectively inhibits browning caused by enzymatic reactions and oxidation, allowing the processed medicinal materials to maintain a color closer to their natural state and excellent appearance, thereby increasing their commercial value. 2. This invention utilizes the cavitation effect and mechanical action of ultrasound to enhance mass transfer, and assists the rapid and selective volumetric heating characteristics of microwaves to achieve efficient, rapid, and complete inactivation of oxidative enzymes (such as polyphenol oxidase and peroxidase) inside fresh-cut stem medicinal materials. This innovative synergistic physical field treatment method not only significantly improves enzyme inactivation efficiency and shortens processing time, but also helps to complete the enzyme inactivation process under relatively mild process conditions, reducing thermal damage to the overall matrix of the medicinal material. 3. The composite natural extract treatment solution used in this invention contains multiple natural polyphenol antioxidants, natural organic acids, and other components that not only synergistically inhibit enzyme activity and protect color, but also provide a certain degree of protection for the inherent medicinal components in the herbs during subsequent ultrasonic-microwave synergistic treatment. By optimizing the synergistic matching of chemical pretreatment and physical field parameters, this invention can effectively inactivate enzymes and protect color while minimizing the degradation and loss of the original heat-sensitive or easily oxidized medicinal components in fresh-cut stem herbs, thereby better preserving the intrinsic medicinal value of the herbs.

[0019] 4. This invention comprehensively improves the color stability, enzyme activity inhibition degree, and effective component retention rate of processed medicinal materials by combining the multiple effects of compound natural extracts with the synergistic effect of ultrasonic-microwave physical field. It significantly improves many shortcomings of traditional primary processing methods and provides a high-quality and highly stable raw material guarantee for subsequent drying, storage, deep processing and clinical application. Attached Figure Description

[0020] Figure 1 This is the process flow diagram of this application; Detailed Implementation

[0021] Combined with appendix Figure 1 This application will be described in further detail below.

[0022] Example 1: The synergistic processing technology for fresh-cut stem medicinal materials—enzyme inactivation and color protection—includes the following steps: S1. Raw material pretreatment and fresh cutting Select 500g of fresh astragalus root, wash off the surface dirt with running water, and let it air dry in a ventilated place for 30 minutes. Use a high-speed slicer (blade material: 440C stainless steel) to slice the astragalus root into uniform thin slices with a thickness of 5.0mm. The freshly sliced ​​astragalus root slices should be added to the subsequent processing within 5 minutes.

[0023] S2. Preparation of compound natural extract treatment solution Prepare 1000 mL of treatment solution according to the following components and concentrations: Natural polyphenol antioxidant complex: Weigh appropriate amounts of green tea extract (total polyphenol content ≥90% based on gallic acid equivalent) and grape seed extract (proanthocyanidin content ≥95%), so that the final mass concentration of polyphenols contributed by green tea extract in the treatment solution is 0.5% (w / v), the final mass concentration of polyphenols contributed by grape seed extract is 0.5% (w / v), and the total mass concentration of polyphenols is 1.0% (w / v).

[0024] Natural organic acids or enzyme activity regulators: Food-grade citric acid and L-ascorbic acid were added to achieve final mass concentrations of 0.5% (w / v) and 0.3% (w / v) respectively in the treatment solution, for a total concentration of 0.8% (w / v). The pH of the treatment solution was adjusted to 4.5 using the citric acid.

[0025] Natural penetration enhancer or film-forming agent: Add food-grade low molecular weight chitosan (degree of deacetylation >85%, molecular weight <50kDa) to make its final mass concentration in the treatment solution 0.25% (w / v).

[0026] Solvent: Deionized water. Add each component to deionized water and stir magnetically at room temperature (22°C) until completely dissolved.

[0027] S3, Integrated Collaborative Processing Immediately add the freshly cut Astragalus membranaceus slices obtained in step 1 to the 1000mL of compound natural extract treatment solution prepared in step S2. At this time, the material-to-liquid ratio is 1:2 (g / mL). (If 500g of medicinal material is used, then 250mL of treatment solution is required. If 1000mL of treatment solution is used, the amount of medicinal material should be adjusted, or the material-to-liquid ratio should be expressed as the volume ratio of medicinal material to treatment solution. For example, if 500g of medicinal material is immersed in 1000mL of treatment solution, the material-to-liquid ratio is understood as 0.5g / mL or 1:2 when expressed as g / mL. Here, we take 100g of medicinal material and 600mL of treatment solution as an example, with a material-to-liquid ratio of 1:6g / mL.)

[0028] Take 100g of freshly cut Astragalus membranaceus slices and add them to 600mL of treatment solution (solid-to-liquid ratio 1:6g / mL). The initial temperature of the treatment solution is 22℃.

[0029] Then, ultrasonic and microwave devices are activated for simultaneous and coordinated processing: Ultrasonic processing parameters: working frequency set to 40kHz, output power density adjusted to 175W / L, continuous action for 6 minutes.

[0030] Microwave processing parameters: Microwave frequency is 2450MHz. Adjust the microwave output power to rapidly raise the internal temperature of the treatment liquid and Astragalus tablets to 62℃ within 5 minutes, and maintain this temperature for 6 minutes.

[0031] Total collaborative processing time: The total time for the entire integrated collaborative processing (simultaneous action of ultrasound and microwave) is 11 minutes.

[0032] S4. Leaching and Drying Treatment After the co-processing is completed, immediately stop the ultrasonic and microwave output, quickly remove the Astragalus slices from the treatment solution, place them on a vibrating screen to drain off the treatment solution adhering to the surface for about 1 minute.

[0033] After draining, the Astragalus membranaceus slices are evenly spread on a stainless steel drying tray and placed in a 60°C hot air circulating oven for drying until the moisture content of the Astragalus membranaceus slices drops to 10% (w / w).

[0034] Example 2: The synergistic processing technology for fresh-cut stem medicinal materials—enzyme inactivation and color protection—includes the following steps: S1. Raw material pretreatment and fresh cutting Select 500g of fresh Salvia miltiorrhiza, wash and drain. Use a high-speed slicer to cut the Salvia miltiorrhiza into uniform slices with a thickness of 2.0mm. The freshly sliced ​​Salvia miltiorrhiza slices should be added to the subsequent processing within 10 minutes.

[0035] S2. Preparation of compound natural extract treatment solution Prepare 1000 mL of treatment solution according to the following components and concentrations: Natural polyphenol antioxidant complex: Weigh an appropriate amount of bamboo leaf extract (total flavonoids ≥40% as rutin) to ensure that the final mass concentration of total polyphenols contributed by the bamboo leaf extract in the treatment solution (converted or directly used as an indicator of antioxidant content) is 0.2% (w / v).

[0036] Natural organic acids or enzyme activity regulators: Add food-grade L-ascorbic acid to a final mass concentration of 0.1% (w / v) in the treatment solution. Adjust the pH of the treatment solution to 5.5 using this L-ascorbic acid (or with a very small amount of citric acid).

[0037] Natural penetration enhancer or film-forming agent: This component is not added in this embodiment (or can be understood as 0% addition, or 0.01% tea saponin added). For clarity, it is set here that tea saponin extract is added so that its final mass concentration in the treatment solution is 0.01% (w / v).

[0038] Solvent: Deionized water. Add each component to deionized water and stir magnetically at room temperature (15°C) until completely dissolved.

[0039] S3. Integrated Co-processing: Take 100g of freshly cut Salvia miltiorrhiza slices and add them to 1000mL of treatment solution (material-to-liquid ratio 1:10g / mL). The initial temperature of the treatment solution is 15℃.

[0040] A sequential collaborative mode of microwave processing followed by ultrasonic pretreatment is adopted: Ultrasonic processing parameters: working frequency set to 20kHz, output power density adjusted to 50W / L, continuous action for 2 minutes.

[0041] Microwave treatment parameters: Immediately after ultrasonic treatment, start the microwave. The microwave frequency is 2450MHz. Adjust the microwave output power to rapidly raise the temperature of the treatment solution and the internal temperature of the Danshen tablets to 50℃ within 8 minutes, and maintain this temperature for 2 minutes.

[0042] Total processing time: 2 minutes for ultrasonic treatment, 10 minutes for microwave treatment (8 minutes of heating + 2 minutes of holding = 10 minutes), and a total processing time of 12 minutes for step S3.

[0043] S4, Leaching and Drying Treatment After the collaborative processing is completed, the operation is the same as in Example 1.

[0044] After draining, the Danshen slices were placed in a vacuum drying oven and dried under a vacuum of 0.08 MPa and a heating plate temperature of 45°C until the moisture content of the Danshen slices dropped to 13% (w / w).

[0045] Example 3: The synergistic processing technology for fresh-cut stem medicinal materials—enzyme inactivation and color protection—includes the following steps: S1. Raw material pretreatment and fresh cutting Select 500g of fresh kudzu root, wash and drain. Use a slicing machine to cut the kudzu root into 5.0cm long segments, then cut the segments lengthwise into strips 10.0mm thick. Place the freshly cut kudzu root strips into the subsequent processing within 2 minutes.

[0046] S2. Preparation of compound natural extract treatment solution Prepare 1000 mL of treatment solution according to the following components and concentrations: Natural polyphenol antioxidant complex: Weigh appropriate amounts of rosemary extract (rosmarinic acid content ≥20%) and green tea extract (tea polyphenol content ≥90%), so that the final mass concentration of total polyphenols contributed by rosemary extract in the treatment solution is 1.0% (w / v), the final mass concentration of total polyphenols contributed by green tea extract is 1.0% (w / v), and the total mass concentration of total polyphenols is 2.0% (w / v).

[0047] Natural organic acids or enzyme activity regulators: Food-grade phytic acid and L-ascorbic acid palmitate were added to achieve final mass concentrations of 1.0% (w / v) and 0.5% (w / v) respectively in the treatment solution, for a total concentration of 1.5% (w / v). The pH of the treatment solution was adjusted to 3.5 using phytic acid (or supplemented with citric acid).

[0048] Natural penetration enhancer or film-forming agent: Add food-grade sodium alginate to achieve a final mass concentration of 0.5% (w / v) in the treatment solution.

[0049] Solvent: 5.0% (v / v) food-grade ethanol aqueous solution (i.e., 50 mL ethanol mixed with 950 mL deionized water). Add each component to the ethanol aqueous solution and stir magnetically at room temperature (30°C) until completely dissolved.

[0050] S3, Integrated Collaborative Processing Take 300g of freshly cut kudzu root strips and put them into 900mL of treatment solution (material-to-liquid ratio 1:3g / mL). The initial temperature of the treatment solution is 30℃.

[0051] Then, ultrasonic and microwave devices are activated for simultaneous and coordinated processing: Ultrasonic processing parameters: working frequency set to 60kHz, output power density adjusted to 300W / L, continuous action for 10 minutes.

[0052] Microwave processing parameters: Microwave frequency is 915MHz. Adjust the microwave output power to rapidly raise the temperature of the treatment liquid and the inside of the kudzu root strips to 75℃ within 2 minutes, and maintain this temperature for 10 minutes.

[0053] Total collaborative processing time: The total time for the entire integrated collaborative processing (simultaneous action of ultrasound and microwave) is 12 minutes (with microwave action time as the main factor, of which 10 minutes overlap with ultrasound action).

[0054] S4, Leaching and Drying Treatment After the collaborative processing is completed, the operation is the same as in Example 1.

[0055] After draining, spread the kudzu root strips evenly on a stainless steel drying tray and put them into a 65℃ hot air circulating oven for drying at a wind speed of 2.0m / s until the moisture content of the kudzu root strips drops to 8% (w / w).

[0056] Comparative Example 1: Compared with Example 1, the difference is that in step S2, the fresh-cut medicinal materials are immersed in an equal volume of deionized water (i.e., without the compound natural extract), and in step S3, ultrasonic treatment and microwave treatment are not applied. The medicinal materials are simply soaked in deionized water for the same total synergistic treatment time (11 minutes) as in S3 of Example 1. The rest (including the fresh cutting in step S1 and the draining and drying in step S4) are the same as in Example 1.

[0057] Comparative Example 2: Compared with Example 1, the difference is that steps S2 and S3 are replaced with traditional hot water blanching treatment: the fresh-cut astragalus slices obtained in step S1 of Example 1 are blanched in hot water at 95°C for 2 minutes, and then directly enter the draining and drying treatment in step S4. The rest are the same as in Example 1.

[0058] Comparative Example 3: Compared with Example 1, the difference is that in step S2, the compound natural extract treatment solution is replaced with an equal volume of deionized water, but in step S3, ultrasonic treatment and microwave treatment are still applied according to the parameters of Example 1, and the rest is the same as Example 1.

[0059] Comparative Example 4: Compared with Example 1, the difference is that ultrasonic treatment and microwave treatment are not applied in step S3. Instead, the fresh-cut medicinal materials immersed in the compound natural extract treatment solution in step S2 of Example 1 are left to stand and soak in the treatment solution. The soaking time is the same as the total synergistic treatment time in S3 of Example 1 (11 minutes). All other aspects are the same as in Example 1.

[0060] Comparative Example 5: Compared with Example 1, the difference is that in step S3, only ultrasonic treatment with the same parameters as in Example 1 is applied (working frequency 40kHz, output power density 175W / L, continuous action for 6 minutes), and then microwave treatment is not performed and the process proceeds directly to step S4. The rest is the same as in Example 1.

[0061] Comparative Example 6: Compared with Example 1, the difference is that in step S3, only microwave treatment with the same parameters as in Example 1 is applied (microwave frequency 2450MHz, microwave output power is adjusted to make the internal temperature of the treatment liquid and Astragalus tablets rise rapidly to 62°C within 5 minutes and maintain at this temperature for 6 minutes), and ultrasonic treatment is not applied. All other aspects are the same as in Example 1.

[0062] Comparative Example 7: Compared with Example 1, the difference is that the natural polyphenol antioxidant complex in the compound natural extract treatment solution in step S2 is replaced with a single component: only green tea extract is used, and its total polyphenol mass concentration in the treatment solution is still 1.0% (w / v) (i.e., no grape seed extract is added), while the other components and parameters are the same as in Example 1.

[0063] Comparative Example 8: Compared with Example 1, the difference is that citric acid and L-ascorbic acid are not added to the compound natural extract treatment solution in step S2 (i.e., the natural organic acid or enzyme activity regulator component is 0%), so the pH value of the treatment solution is not specially adjusted (it is the natural pH value after the extract is dissolved), and the other components and parameters are the same as in Example 1.

[0064] Comparative Example 9: Compared with Example 1, the difference is that the total polyphenol mass concentration of the natural polyphenol antioxidant complex (green tea extract and grape seed extract) in the compound natural extract treatment solution in step S2 is reduced to 0.1% (w / v), while the remaining components and parameters are the same as in Example 1.

[0065] Comparative Example 10: Compared with Example 1, the difference is that the microwave processing parameters in step S3 are adjusted to raise the internal temperature of the treatment liquid and Astragalus tablets to 45°C within 5 minutes and maintain this temperature for 1 minute. The remaining ultrasonic parameters and other steps are the same as in Example 1.

[0066] Comparative Example 11: Compared with Example 1, the difference is that the pH value of the compound natural extract treatment solution in step S2 is adjusted to 7.5, while the other components and parameters are the same as in Example 1.

[0067] Test Example 1: Overall effect of the synergistic processing technology of the present invention and its comparison with traditional technology. Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), after being washed and drained, a portion was immediately fresh-cut (5.0 mm thick) for immediate determination of color and enzyme activity, or rapidly frozen in liquid nitrogen and then freeze-dried for subsequent indicator determination.

[0068] Example 1 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Example 1" above.

[0069] Comparative Example 1 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 1" (soaked in water, without compound extracts, and without ultrasound or microwave).

[0070] Comparative Example 2 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 2" (traditional hot water blanching treatment).

[0071] Experimental steps: Color evaluation Take an appropriate amount (e.g., 5-10 tablets, or about 2g after crushing and passing through a 40-mesh sieve) of each group of dried samples (C0, Example 1, Comparative Example 1, Comparative Example 2) and place it in the sample dish of a colorimeter (e.g., a Konica Minolta CM-5 colorimeter), ensuring that the measurement aperture is covered.

[0072] Instrument calibration: Calibrate using a standard whiteboard and blackboard.

[0073] Parameter settings: Select CIEL * a * b * Color space, D65 light source, 10° standard observer's field of view.

[0074] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * (Brightness, 0 for black, 100 for white), a * (Red-green axis, positive values ​​are red, negative values ​​are green) and b * (Yellow-blue axis, positive values ​​are yellow, negative values ​​are blue) values.

[0075] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The calculation formula is: Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 1, Comparative Example 2) (if it is a lyophilized sample, calculate based on fresh weight or use the lyophilized sample uniformly; if it is a dried sample, use the dried sample uniformly), and add 5mL of pre-cooled phosphate buffer (0.1M, pH 6.8, containing 1% PVPP).

[0076] Homogenize at high speed for 2 minutes using a tissue homogenizer under ice bath conditions.

[0077] Centrifuge the homogenate at 4℃ and 10000×g for 20 minutes, and take the supernatant as the crude PPO enzyme solution, and place it in an ice bath for testing.

[0078] PPO activity assay: Reaction system (total volume 3.0 mL): 2.7 mL phosphate buffer (0.1 M, pH 6.8), 0.1 mL substrate solution (0.2 M catechol, freshly prepared with the above buffer), and 0.2 mL crude enzyme solution to start the reaction.

[0079] Immediately at 25°C, use a UV-Vis spectrophotometer to continuously monitor the absorbance value at a wavelength of 420 nm and record the absorbance change curve within 3 minutes after the start of the reaction.

[0080] Enzyme activity unit (U) definition: Under the above measurement conditions, an increase of 0.001 absorbance value per minute is defined as one enzyme activity unit.

[0081] Calculate: PPO activity (U / g·min) = (ΔA) 420 / min×total volume of reaction system) / (volume of enzyme solution taken×fresh weight or dry weight of sample).

[0082] Residual enzyme activity (%) = (PPO activity of treated sample / PPO activity of CO sample) × 100%.

[0083] Determination of the content of major active ingredients (taking astragaloside A as an example) Sample pretreatment: Accurately weigh approximately 0.2 g of each group of dried sample powder (Example 1, Comparative Example 1, Comparative Example 2, and the freeze-dried sample of C0) through a 60-mesh sieve.

[0084] Place the contents in a stoppered conical flask, add 25 mL of methanol precisely, and weigh.

[0085] Ultrasonic treatment (power 250W, frequency 40kHz) for 30 minutes, remove, cool, weigh again, replenish the lost weight with methanol, shake well, and filter.

[0086] Accurately measure 5 mL of the filtrate, place it in a 50 mL volumetric flask, add methanol to the mark, and shake well to obtain the test solution.

[0087] Preparation of reference solution: Accurately weigh an appropriate amount of astragaloside A reference standard, add methanol to prepare a solution containing 0.1 mg per 1 mL, which is used as the reference solution.

[0088] Determination and Calculation: Accurately pipette 10 μL each of the reference solution and the test solution into the liquid chromatograph and record the chromatograms. Calculate the content (mg / g) of astragaloside A in each sample based on peak area using the external standard method.

[0089] The test data is shown in Table 1: Table 1: Effects of different treatment methods on color parameters, residual PPO activity, and astragaloside A content of Astragalus membranaceus Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> b* <![CDATA[ΔE * ]]> Residual PPO activity (%) Astragaloside A content (mg / g) C0 (Fresh Control) 78.5 1.2 22.5 0 100 0.85 Example 1 75.1 0.8 20.3 4.1 7.2 0.78 Comparative Example 1 62.3 -1.5 15.8 18.5 85.3 0.51 Comparative Example 2 68.9 -0.5 18.1 11.2 25.7 0.63 Experiment Summary: The experimental results clearly show that the Astragalus membranaceus sample processed using the integrated synergistic treatment process of this invention (Example 1) is significantly superior to the untreated (Comparative Example 1) and traditional hot water blanching (Comparative Example 2) samples in terms of color retention, enzyme activity inhibition, and retention of major active ingredients. Specifically, the ΔE of the sample in Example 1 * The lowest value indicates that its color is closest to that of fresh medicinal materials. This is due to the fact that the polyphenolic antioxidants in the compound natural extract treatment solution (such as EGCG and proanthocyanidins in green tea extract and grape seed extract) can effectively remove free radicals generated by tissue damage and can compete with or directly inhibit the activity of polyphenol oxidase (PPO) substrates, thereby delaying the browning reaction. At the same time, the addition of natural organic acids (such as citric acid and L-ascorbic acid) in the treatment solution adjusts the microenvironment pH to the non-optimal range of PPO and peroxidase (POD) and can chelate the metal ion cofactors (such as Cu) necessary for the catalytic reaction of these enzymes. 2+ This further inhibited the process of enzymatic browning.

[0090] Compared to the water soaking in Comparative Example 1 (where enzyme activity remained high, color deteriorated significantly, and active ingredient loss was substantial) and the traditional hot water rinsing in Comparative Example 2 (which could inactivate enzymes to some extent, but the high temperature caused irreversible damage to color and heat-sensitive active ingredients), the synergistic application of ultrasound and microwaves in the process of this invention plays a crucial enhancing role. The cavitation effect and mechanical vibration of ultrasound promote the rapid penetration and uniform distribution of color-protecting and enzyme-inhibiting components in the compound natural extract treatment solution into the tissue of the medicinal material, improving the utilization efficiency of active components and causing some physical damage to the enzyme protein structure; while the selective rapid volumetric heating characteristics of microwaves enable the medicinal material to uniformly reach the set enzyme inactivation temperature (such as 62°C in Example 1) in a short time, achieving efficient and rapid inactivation of endogenous oxidases such as PPO. Furthermore, due to the short heating time and controllable overall temperature rise, excessive damage to the color and heat-sensitive active ingredients (such as astragaloside A) of the medicinal material caused by prolonged high-temperature treatment is avoided.

[0091] Therefore, the core advantage of this invention lies in the organic combination of the chemical protective effect of the compound natural extract treatment solution with the enhanced mass transfer and efficient enzyme inactivation effect of the ultrasonic-microwave synergistic physical field, forming an integrated synergistic strategy of "fresh cutting - chemical pretreatment - physical field-enhanced enzyme inactivation and color protection". This strategy not only effectively inhibits the enzymatic browning of freshly cut stem medicinal materials and maximizes the preservation of the natural color of the medicinal materials, but more importantly, it significantly improves the retention rate of the main active ingredients through gentle yet efficient synergistic treatment.

[0092] Test Example 2: Evaluation of the Key Roles of Compound Natural Extract Processing Solution and its Components Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0093] Example 1 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Example 1" above.

[0094] Comparative Example 3 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 3" (ultrasonic and microwave treatment, but water was used instead of the compound extract).

[0095] Comparative Example 7 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of "Comparative Example 7" (the natural polyphenol antioxidant in the compound extract is a single component: only green tea extract).

[0096] Comparative Example 8 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of "Comparative Example 8" (the compound extract contained no natural organic acids or enzyme activity regulators, and the pH was not adjusted).

[0097] Comparative Example 9 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of "Comparative Example 9" (the total concentration of natural polyphenol antioxidants in the compound extract was lower than the lower limit of the optimization range: 0.1%).

[0098] Comparative Example 11 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of “Comparative Example 11” above (the pH value of the compound extract is higher than the upper limit of the optimized range: pH 7.5).

[0099] Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 3, Comparative Example 7, Comparative Example 8, Comparative Example 9, Comparative Example 11) and perform instrument calibration and parameter setting as in steps 1-3 of “2.1 Color Evaluation” in Test Example 1.

[0100] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0101] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0102] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 3, Comparative Example 7, Comparative Example 8, Comparative Example 9, Comparative Example 11) and extract crude enzyme solution as in step 1 of “Residual Enzyme Activity Determination” in Test Example 1.

[0103] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0104] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step S3 of "Residual Enzyme Activity Assay" in Test Example 1.

[0105] Determination of the content of main active ingredients Sample pretreatment: Accurately weigh approximately 0.2 g of the dried powder of the sample from Example 1, the comparative sample (and the freeze-dried sample of C0), and perform sample pretreatment as in step 1 of "Determination of the content of main active ingredients" in Test Example 1.

[0106] Preparation of reference solution and HPLC conditions: Same as steps 2 and 3 of "Determination of content of main active ingredients" in Test Example 1.

[0107] Measurement and calculation: Perform the measurement and calculation as in step 4 of “Determination of the content of main effective ingredients” in Test Example 1.

[0108] The experimental data are shown in Table 2: Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> <![CDATA[ΔE * ]]> Residual PPO activity (%) Astragaloside A content (mg / g) C0 (Fresh Control) 78.2 1.1 22.8 0 100 0.86 Example 1 74.8 0.9 20.1 4.3 6.9 0.79 Comparative Example 3 65.5 -0.8 16.2 15.1 35.2 0.58 Comparative Example 7 71.3 0.2 19 7.9 15.8 not applicable Comparative Example 8 69 -0.2 17.5 11.5 28.4 not applicable Comparative Example 9 70.1 0.1 18.3 9.8 22.1 not applicable Comparative Example 11 67.2 -0.9 16.9 13.7 40.5 not applicable Experiment Summary: Experimental results reveal the crucial role of the composite natural extract treatment solution and its specific components in the synergistic treatment process of this invention. Comparing Example 1 with Comparative Example 3 (water as a substitute treatment solution), it can be observed that even under the same ultrasonic and microwave physical fields, the lack of chemical protection from the composite natural extract still results in significant color deterioration of the samples (ΔE). * The residual enzyme activity was significantly higher than in Example 1, and the retention rate of the main active ingredient, astragaloside A, was also greatly reduced. This fully demonstrates that the compound natural extract treatment solution is not a simple wetting medium, but rather participates directly in the processes of color protection, enzyme inhibition, and stabilization of the active ingredients through its contained active components. It is an indispensable core element for achieving the expected effects of this invention. The active molecules in the treatment solution can react with the oxidative environment before the endogenous substrates of the medicinal materials, or act directly on enzyme molecules, thereby providing a chemical protective barrier for the medicinal materials.

[0109] Further analysis of the component optimization effect of the compound natural extract treatment solution: Comparing Example 1 (compound of polyphenolic antioxidants) with Comparative Example 7 (single phenolic antioxidant), Example 1 showed better performance in both color retention and enzyme activity inhibition. This indicates that natural polyphenolic compounds from different sources and with different structures (such as EGCG, proanthocyanidins, etc.) may have synergistic effects in terms of free radical scavenging types, action targets, or regeneration mechanisms, making the overall antioxidant capacity and enzyme inhibition effect of the compound system stronger than that of a single component. Meanwhile, comparing the results of Example 1 with Comparative Example 9 (polyphenol concentration too low), it shows that when the concentration of polyphenolic antioxidants is insufficient, their protective effect will significantly decrease. This emphasizes the importance of maintaining the active components within a certain concentration range to ensure sufficient molecules participate in the reaction and reach an effective protective threshold.

[0110] The pH environment and its adjustment mechanism of the compound natural extract treatment solution also significantly affect the final effect. Comparing Example 1 (pH 4.5, containing citric acid and L-ascorbic acid) with Comparative Example 8 (unadjusted pH, no organic acids) and Comparative Example 11 (pH 7.5, outside the optimal range), the sample from Example 1 showed the best performance in terms of color and enzyme activity inhibition. This is attributed to the fact that natural organic acids such as citric acid and L-ascorbic acid not only possess antioxidant properties themselves, but also directly inhibit the catalytic activity of browning-related enzymes such as polyphenol oxidase by adjusting the pH of the treatment solution to a weakly acidic environment (e.g., pH 3.5-5.5), a pH range significantly deviating from the optimal pH. Furthermore, these organic acids may also inhibit the catalytic activity of browning-related enzymes such as polyphenol oxidase by chelating metal ions (e.g., Cu). 2+ This reduces the cofactors necessary for the enzymatic reaction, further enhancing the enzyme inhibition effect. However, if the pH is too high or not adjusted, this pH-based enzyme activity inhibition and synergistic color protection mechanism cannot be fully utilized.

[0111] Test Example 3: Evaluation of the Key Role and Parameter Influence of Synergistic Physical Field Processing Using Ultrasonic and Microwave Technologies Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0112] Example 1 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Example 1" above.

[0113] Comparative Example 4 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 4" (containing compound natural extract treatment solution, but without ultrasonic and microwave treatment, only soaking).

[0114] Comparative Example 5 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 5" (containing compound natural extract treatment solution, ultrasonic treatment only, no microwave treatment).

[0115] Comparative Example 6 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Comparative Example 6" (containing compound natural extract treatment solution, microwave treatment only, no ultrasound).

[0116] Comparative Example 10 Sample: Dried Astragalus membranaceus slices prepared according to the steps of “Comparative Example 10” (containing compound natural extract treatment solution, ultrasonic parameters are the same as in Example 1, but microwave treatment temperature and holding time are lower than the lower limit of the optimization range).

[0117] Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 10) and perform instrument calibration and parameter setting as in steps 1-3 of "Color Evaluation" in Test Example 1.

[0118] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0119] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0120] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 10) and extract crude enzyme solution as in step 1 of “Residual Enzyme Activity Determination” in Test Example 1.

[0121] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0122] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step 3 of “Residual Enzyme Activity Assay” in Test Example 1.

[0123] Determination of the content of major active ingredients (taking astragaloside A as an example) Sample pretreatment: Accurately weigh approximately 0.2 g of powder from each group of dried samples (Example 1, Comparative Example 4, Comparative Example 5, Comparative Example 6, and the freeze-dried sample of CO) and perform sample pretreatment as in step 1 of "Determination of Content of Main Active Ingredients" in Test Example 1.

[0124] Preparation of reference solution and HPLC conditions: Same as steps 2 and 3 of "Determination of content of main active ingredients" in Test Example 1.

[0125] Measurement and calculation: Perform the measurement and calculation as in step 4 of “Determination of the content of main effective ingredients” in Test Example 1.

[0126] The experimental data are shown in Table 3: Table 3: Effects of different physical field treatment conditions on color parameters, residual PPO activity and astragaloside A content of Astragalus membranaceus Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> <![CDATA[ΔE * ]]> Residual PPO activity (%) Astragaloside A content (mg / g) C0 (Fresh Control) 78.4 1.3 22.6 0 100 0.84 Example 1 75 0.7 20.5 4 7.1 0.77 Comparative Example 4 67.8 -0.4 17.2 12.6 45.8 0.61 Comparative Example 5 70.5 0.1 18.9 8.7 28.3 0.69 Comparative Example 6 72.1 0.4 19.5 6.9 18.5 0.72 Comparative Example 10 71.2 0.3 19.1 7.8 33.9 0.67 Experiment Summary: The results of this test strongly demonstrate the key role and synergistic effect mechanism of the combined ultrasonic and microwave physical field treatment in the process of this invention. Comparing Example 1 (combined ultrasonic and microwave treatment) and Comparative Example 4 (immersion in the composite natural extract only, without physical field treatment), the former showed a significantly better color retention effect (ΔE). * The results showed significantly better reductions in particle size, enzyme activity inhibition (lower residual PPO activity), and retention of active ingredients. This indicates that passive diffusion and action of chemical treatment solutions alone are insufficient to achieve the desired effect; the introduction of a physical field can greatly enhance the entire treatment process. The cavitation effect, acoustic flow, and mechanical vibration generated by ultrasound can effectively disrupt the structure of the cell walls and cell membranes of medicinal materials, forming microchannels. This significantly accelerates the penetration rate and depth of active ingredients in the compound natural extract into the medicinal tissue, improving the contact efficiency between chemical components, enzymes, and substrates.

[0127] Further comparison of the results of Example 1 with Comparative Example 5 (ultrasonic treatment only) and Comparative Example 6 (microwave treatment only) clearly demonstrates the superiority of the synergistic effect of ultrasound and microwave. Although applying ultrasound or microwave alone can improve the treatment effect to some extent compared to simple immersion (Comparative Example 4), their effects are not as good as those of Example 1 with the synergistic effect of both. Although ultrasonic treatment alone (Comparative Example 5) can promote mass transfer, its direct enzyme inactivation ability and heating efficiency are limited; although microwave treatment alone (Comparative Example 6) can rapidly heat up and inactivate enzymes, its mass transfer may not be as uniform as that under ultrasound assistance, and there may be a risk of local overheating. The synergy of ultrasound and microwave combines the advantages of ultrasound in enhancing mass transfer, dispersing materials, and assisting in cell wall disruption, with the characteristics of microwave in achieving efficient enzyme inactivation through rapid, uniform, and selective heating. Ultrasonic pretreatment or simultaneous treatment can create more favorable conditions for subsequent or simultaneous microwave heating enzyme inactivation, making enzyme molecules more easily exposed and acted upon by microwave energy, thereby achieving a more thorough enzyme inactivation effect under gentler conditions (such as lower overall temperature and shorter time), while better protecting heat-sensitive components.

[0128] Furthermore, comparing the results of Example 1 with those of Comparative Example 10 (where microwave treatment parameters were below the optimal range) demonstrates the importance of microwave treatment parameters (such as temperature and duration) within a specific optimal range. When the final microwave treatment temperature is not reached or the duration is insufficient, enzyme inactivation is inadequate, resulting in high residual enzyme activity and a corresponding decrease in color protection and retention of active ingredients. This indicates that the specific range of microwave treatment parameters in this invention is determined based on the consideration of fully inactivating the target enzymes (such as PPO and POD) while minimizing negative impacts on the quality of the medicinal materials. Deviating from this range makes it difficult to achieve the optimal synergistic treatment effect. Therefore, the synergistic effect of ultrasound and microwaves, as well as the precise control of various physical field parameters, are the core technical support for achieving efficient enzyme inactivation, excellent color protection, and high-quality ingredient retention in this invention.

[0129] Test Example 4: Evaluation of the Importance of the Range of Key Physical Field Process Parameters Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0130] Example 1 Sample: Dried Astragalus membranaceus slices prepared according to the steps of "Example 1" above (microwave treatment: heated to 62°C and maintained for 6 minutes).

[0131] Comparative Example 10 Sample: Dried Astragalus membranaceus slices prepared according to the steps of “Comparative Example 10” (containing compound natural extract treatment solution, ultrasonic parameters are the same as in Example 1, but microwave treatment parameters are adjusted to: heat up to 45°C and maintain for 1 minute).

[0132] Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 10) and perform instrument calibration and parameter setting as in steps 1-3 of “2.1 Color Evaluation” in Test Example 1.

[0133] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0134] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0135] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 10) and extract crude enzyme solution as in step 1 of "Residual enzyme activity determination" in Test Example 1.

[0136] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0137] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step 3 of “Residual Enzyme Activity Assay” in Test Example 1.

[0138] Determination of the content of major active ingredients (taking astragaloside A as an example) Sample pretreatment: Accurately weigh approximately 0.2 g of powder from each group of dried samples (Example 1, Comparative Example 10, and freeze-dried sample of CO) and perform sample pretreatment as in step 1 of "Determination of Content of Main Active Ingredients" in Test Example 1.

[0139] Preparation of reference solution and HPLC conditions: Same as steps 2 and 3 of "Determination of content of main active ingredients" in Test Example 1.

[0140] Measurement and calculation: Perform the measurement and calculation as in step 4 of “Determination of the content of main effective ingredients” in Test Example 1.

[0141] The experimental data are shown in Table 4: Table 4: Effects of different microwave treatment parameters on color parameters, residual PPO activity and astragaloside A content of Astragalus membranaceus Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> <![CDATA[ΔE * ]]> Residual PPO activity (%) Astragaloside A content (mg / g) C0 (Fresh Control) 78.6 1.2 22.4 0 100 0.85 Example 1 74.9 0.8 20.2 4.2 7 0.78 Comparative Example 10 69.5 -0.1 18 10.3 38.7 0.65 Experiment Summary: The results of this test case highlight the extreme importance of precisely controlling and maintaining key physical field parameters, particularly the temperature and time of microwave processing, within a specific optimized range in the integrated synergistic processing technology of this invention. Comparing Example 1 (microwave processing parameters: heating to 62°C and holding for 6 minutes) with Comparative Example 10 (microwave processing parameters: heating to 45°C and holding for 1 minute), the former showed better color retention (ΔE). * The invention exhibits significant advantages in terms of significantly lower residual PPO activity, enzyme inactivation effect (significantly lower residual PPO activity), and retention rate of the main active ingredient, astragaloside A. This directly reflects the decisive influence of microwave processing parameter settings on achieving the expected technical effect of this invention; deviation from the optimized parameter range will lead to a significant reduction in process effectiveness.

[0142] Microwaves, as a highly efficient volumetric heating technology, work by inducing high-speed rotation and friction of polar molecules (mainly water molecules) within medicinal materials through a high-frequency electromagnetic field. This rapid and uniform heating inactivates endogenous oxidases (such as PPO and POD). These enzymes are the main cause of browning and quality deterioration in freshly cut medicinal materials. The denaturation and inactivation of enzymes are highly dependent on temperature and heating time for the thermal instability of their tertiary structure. When the target temperature of microwave treatment is too low (e.g., 45℃ in Comparative Example 10) or the holding time is too short (e.g., 1 minute in Comparative Example 10), the enzyme protein molecules do not receive sufficient energy to undergo adequate conformational changes and destruction of key active sites, resulting in incomplete enzyme inactivation. Therefore, the higher residual PPO activity in Comparative Example 10 is expected, which directly leads to more severe color deterioration in the sample, manifested as L * The value is low, ΔE * The value is relatively large.

[0143] One of the innovations of this invention lies in "high-efficiency, low-temperature, rapid enzyme inactivation via microwave" and "optimization and precise control of process parameters." By controlling the microwave enzyme inactivation temperature within a relatively low but effective range (e.g., 50-75°C) and combining it with an appropriate holding time (e.g., 2-10 minutes), it is possible to ensure complete enzyme inactivation while minimizing the degradation of heat-sensitive active ingredients (such as astragaloside A) and the destruction of natural color in the medicinal materials due to excessive heat treatment. Example 1 exemplifies this optimized parameter selection, demonstrating excellent enzyme inactivation and quality preservation. In contrast, the treatment in Comparative Example 10, failing to reach the "energy threshold" required for effective enzyme inactivation, not only failed to effectively inhibit enzymatic browning, but the residual enzyme activity may also continue to exert its effects during subsequent drying and storage, further reducing the quality and content of active ingredients in the medicinal materials.

[0144] Test Example 5: Evaluation of the superiority of polyphenol antioxidant compound in complex natural extracts Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0145] Example 1 Sample: Dried Astragalus membranaceus tablets (a compound natural extract containing green tea extract and grape seed extract) prepared according to the steps of "Example 1" above.

[0146] Comparative Example 7 Sample: Dried Astragalus tablets prepared according to the steps of "Comparative Example 7" (the natural polyphenol antioxidant in the compound natural extract is a single component: only green tea extract, and the total polyphenol concentration is the same as in Example 1).

[0147] Experimental steps Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 7) and perform instrument calibration and parameter setting as in steps 1-3 of "Color Evaluation" in Test Example 1.

[0148] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0149] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0150] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 7) and extract crude enzyme solution as in step 1 of "Residual enzyme activity determination" in Test Example 1.

[0151] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0152] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step 3 of “Residual Enzyme Activity Assay” in Test Example 1.

[0153] The experimental data are shown in Table 5: Table 5: Effects of different polyphenol antioxidant compositions on the color parameters and residual PPO activity of Astragalus membranaceus.

[0154] Experimental conclusion: The results of this test significantly demonstrate that in the compound natural extract treatment solution used in this invention, the combination of multiple natural polyphenol antioxidants (such as the combination of green tea extract and grape seed extract in Example 1) has a superior effect on maintaining the color of medicinal materials and inhibiting enzyme activity compared to using a single source of natural polyphenol antioxidants (such as using only green tea extract in Comparative Example 7, even with the same total polyphenol concentration). ΔE of the sample in Example 1 * The smaller value indicates that its color is closer to that of a fresh state, and its residual PPO activity is also significantly lower than that of Comparative Example 7. This fully demonstrates the technical advantage of the innovative point of "multi-element natural antioxidant compound" in this invention.

[0155] This advantage stems from the diversity and synergistic effects of different natural polyphenolic compounds in their antioxidant mechanisms. For example, green tea extract is rich in catechins (such as EGCG), while grape seed extract is rich in proanthocyanidin oligomers and monomers. These polyphenol molecules with different structures may have different free radical scavenging spectra (e.g., targeting different types of reactive oxygen species (ROS) or reactive nitrogen species (RNS), or act on different sites of enzymes, or have different hydrophilic / lipophilic balances, thus affecting their distribution and efficacy within the medicinal tissue. When used in combination, they can form a broader-spectrum and more efficient antioxidant system. Some phenolic compounds may act as the primary free radical scavengers, while others may indirectly exert their effects by regenerating the former or chelating oxidizing metal ions, thereby producing a synergistic effect greater than the sum of its parts (1+1>2).

[0156] Specifically, in the enzymatic browning process, polyphenol oxidase (PPO) catalyzes the oxidation of phenolic substances to quinones, which further polymerize to form dark pigments. The compounded antioxidants not only more effectively scavenge free radicals generated in the initial reaction and interrupt the chain oxidation reaction, but also more comprehensively bind to the active sites of PPO or alter its microenvironment, thereby more effectively inhibiting the enzyme's catalytic activity. While the single antioxidant in Comparative Example 7 also showed some effect, its target sites and mechanisms of action were relatively limited, making it difficult to comprehensively address the complex oxidation process and the synergistic effects of multiple enzymes. This invention, through the careful selection and compounding of multiple natural polyphenol antioxidants, constructs a multi-level, multi-target synergistic antioxidant and enzyme inhibition system. This system highly matches the excellent performance of Example 1 in color preservation and enzyme activity inhibition, and is one of the key technologies for achieving efficient color protection and quality maintenance in this invention.

[0157] Test Example 6: Evaluation of the Importance of Natural Organic Acids and pH Control in Compound Natural Extracts Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0158] Example 1 Sample: Dried Astragalus membranaceus tablets (compound natural extract containing citric acid and L-ascorbic acid, pH adjusted to 4.5) prepared according to the steps of "Example 1" above.

[0159] Comparative Example 8 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of "Comparative Example 8" (the compound natural extract contains no natural organic acids or enzyme activity regulators, and the pH is the natural pH value after the extract is dissolved).

[0160] Comparative Example 11 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of “Comparative Example 11” (the pH value of the compound natural extract was adjusted to 7.5, exceeding the upper limit of the optimization range).

[0161] Experimental steps Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 8, Comparative Example 11) and perform instrument calibration and parameter setting as in steps 1-3 of "Color Evaluation" in Test Example 1.

[0162] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0163] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0164] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 8, Comparative Example 11) and extract crude enzyme solution as in step 1 of "Determination of Residual Enzyme Activity" in Test Example 1.

[0165] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0166] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step 3 of “Residual Enzyme Activity Assay” in Test Example 1.

[0167] The experimental data are shown in Table 6: Table 6: Effects of adding organic acids and controlling pH on the color parameters and residual PPO activity of Astragalus membranaceus in the compound natural extract treatment solution Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> <![CDATA[ΔE * ]]> Residual PPO activity (%) C0 (Fresh Control) 78.5 1.3 22.5 0 100 Example 1 75.1 0.8 20.3 4.1 7.2 Comparative Example 8 68.7 -0.3 17.8 11.9 30.5 Comparative Example 11 66.5 -1 16.5 15.3 42.1 Experiment Summary: The data from this test clearly demonstrate that adding natural organic acids and precisely controlling the pH within a suitable range is crucial for effectively inhibiting enzyme activity and maintaining the color of medicinal materials in the compound natural extract treatment solution used in this invention. The sample from Example 1, whose treatment solution contained citric acid and L-ascorbic acid and was adjusted to pH 4.5, exhibited the lowest ΔE* value and the lowest residual PPO activity, significantly superior to Comparative Example 8 (without added organic acids and no pH adjustment) and Comparative Example 11 (with pH adjusted to 7.5, deviating from the optimal range). This directly proves the effectiveness of the innovative concept of "multifunctional component integration" in this invention, which emphasizes the use of natural organic acids for pH adjustment, auxiliary antioxidant effects, and chelation of metal ions.

[0168] The pH environment of the treatment solution has a direct and significant impact on the catalytic activity of enzymes. Most enzymes, including polyphenol oxidase (PPO) and peroxidase (POD), which cause browning in medicinal materials, have catalytic functions highly dependent on the integrity of their protein tertiary structure and the dissociation state of specific amino acid residues at the active site, all of which are precisely regulated by the ambient pH. When the pH deviates from the enzyme's optimal range, the conformation of the enzyme protein may change, leading to a decrease in the binding capacity of the active site to the substrate or a reduction in catalytic efficiency, or even irreversible denaturation and inactivation. Example 1 controlled the pH at a weakly acidic level (e.g., 4.5), which is significantly lower than the optimal pH for many plant PPO and POD (typically in the neutral to weakly alkaline range), thus directly inhibiting the activity of these enzymes. In contrast, the natural pH of Comparative Example 8 or the pH of Comparative Example 11 (7.5) may be closer to or within the enzyme's optimal activity range, thus exhibiting a poorer inhibitory effect on enzyme activity.

[0169] Besides directly influencing enzyme activity through pH regulation, the natural organic acids (such as citric acid and L-ascorbic acid) added to the treatment solution of this invention also play multiple synergistic roles. First, they are themselves effective pH adjusters, helping to stabilize the pH of the treatment solution within the target enzyme-inhibiting range. Second, many organic acids, especially citric acid, are effective metal ion chelating agents. The activity of oxidases such as PPO often depends on metal ion cofactors (such as Cu). 2+ Citric acid can form stable complexes with these metal ions, thereby depriving enzymes of the cofactors necessary for enzyme activity and indirectly inhibiting their catalytic function. Furthermore, organic acids such as L-ascorbic acid also possess antioxidant capabilities, scavenging free radicals and assisting the main polyphenolic antioxidants in combating oxidative browning. Therefore, this invention, through the introduction of organic acids and precise pH control, achieves multi-dimensional and synergistic inhibition of enzyme activity, a key technical step in ensuring the effective preservation of the color and quality of medicinal materials.

[0170] Test Example 7: Evaluation of the Importance of Concentration Range of Key Components (Polyphenol Antioxidants) in Compound Natural Extracts Experimental materials and samples C0 (control group): Fresh Astragalus membranaceus (same batch as used in Example 1), treated the same as C0 in Test Example 1.

[0171] Example 1 Sample: Dried Astragalus membranaceus tablets prepared according to the steps of "Example 1" above (the total polyphenol mass concentration of the natural polyphenol antioxidant complex in the compound natural extract is 1.0%).

[0172] Comparative Example 9 Sample: The dried Astragalus membranaceus tablets prepared according to the steps of "Comparative Example 9" above (the total polyphenol mass concentration of the natural polyphenol antioxidant complex in the compound natural extract was reduced to 0.1%, which is lower than the lower limit of the optimization range).

[0173] Experimental steps Color evaluation Take appropriate amounts of each group of dried samples (C0, Example 1, Comparative Example 9) and perform instrument calibration and parameter setting as in steps 1-3 of "Color Evaluation" in Test Example 1.

[0174] Measurement: Repeat the measurement 5 times at different locations for each sample and record L. * a * b * The value of .

[0175] Data processing: Calculate L for each sample * a * b * The average value. Based on group C0 (fresh or lyophilized samples). Using C0 as a baseline, calculate the total color difference ΔE of each treatment group sample relative to C0. * The formula is the same as in Test Example 1.

[0176] Residual enzyme activity assay (taking polyphenol oxidase PPO as an example) Crude enzyme extraction: Accurately weigh 0.5g of each group of samples (C0, Example 1, Comparative Example 9) and extract crude enzyme solution as in step 1 of "Residual enzyme activity determination" in Test Example 1.

[0177] PPO activity assay: Take the crude enzyme solution from each group and perform PPO activity assay as in step 2 of “Residual Enzyme Activity Assay” in Test Example 1.

[0178] Calculation: Calculate PPO activity (U / g·min) and residual enzyme activity (%) in step 3 of “Residual Enzyme Activity Assay” in Test Example 1.

[0179] The experimental data are shown in Table 7: Table 7: Effects of different polyphenol antioxidant concentrations on color parameters and residual PPO activity of Astragalus membranaceus Sample group <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> <![CDATA[ΔE * ]]> Residual PPO activity (%) C0 (Fresh Control) 78.4 1.2 22.6 0 100 Example 1 75 0.9 20.5 3.9 7.3 Comparative Example 9 70.3 0.2 18.7 9.2 25.8 Experiment Summary: The results of this test clearly demonstrate that the concentration of one of the key active components—the natural polyphenol antioxidant—in the compound natural extract treatment solution used in this invention has a crucial impact on achieving the ideal color protection and enzyme inhibition effects. Comparing Example 1 (total polyphenol concentration of 1.0%) and Comparative Example 9 (total polyphenol concentration of only 0.1%), under the same other treatment conditions (such as physical field parameters, pH, etc.), the sample of Example 1 showed better color retention (ΔE). *In terms of both smaller size and enzyme activity inhibition (lower residual PPO activity), it is significantly superior to Comparative Example 9. This directly confirms the necessity and scientific validity of optimizing the concentration of active components in the "compounding of multiple natural antioxidants" and "optimization and precise control of process parameters" of this invention.

[0180] Natural polyphenol antioxidants are the core of the chemical protection function of the treatment solution in this invention. They delay or inhibit the oxidative browning process of freshly cut medicinal materials through multiple mechanisms. First, they can directly scavenge reactive oxygen free radicals (such as superoxide anions and hydroxyl radicals) generated by tissue damage. These free radicals are key initiators of chain oxidation reactions, leading to pigment degradation and brown pigment formation. Second, polyphenol compounds themselves can also act as competitive or non-competitive inhibitors of enzymes, competing for binding sites with substrates of browning-related enzymes such as polyphenol oxidase (PPO), or directly binding to enzyme proteins to change their conformation, thereby reducing the catalytic efficiency of the enzyme. When the concentration of polyphenol antioxidants is too low (e.g., Comparative Example 9), the number of effective molecules participating in the above-mentioned antioxidant and enzyme inhibition reactions per unit volume of treatment solution is insufficient, making it difficult to form a sufficient protective barrier to combat the rapidly occurring oxidation and enzymatic reactions.

[0181] Therefore, this invention emphasizes controlling the concentration of polyphenols in the compound natural extract within an optimized range (e.g., 0.2-2.0%), based on considerations of reaction kinetics and stoichiometry. Only when the concentration of antioxidants reaches a certain threshold can it be ensured that they can fully penetrate and effectively interact with a sufficient number of free radicals and enzyme molecules within the limited time of contact with the medicinal tissue, thereby achieving significant color protection and enzyme inhibition effects. The results of Example 1 demonstrate this concentration optimization effect; the sufficient polyphenol antioxidants provided offer strong chemical protection to the medicinal material, which, together with the physical field treatment, effectively maintains the quality of the medicinal material.

[0182] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A synergistic treatment process for fresh-cut stem medicinal materials—enzyme inactivation and color protection—characterized by: Includes the following steps: S1. Freshly cut the stems of medicinal herbs to obtain freshly cut medicinal herbs; S2. Immerse the fresh-cut medicinal materials in a compound natural extract treatment solution, wherein the compound natural extract treatment solution contains at least one natural polyphenol antioxidant complex, at least one natural organic acid or enzyme activity regulator, and a solvent. S3. The fresh-cut medicinal materials immersed in the compound natural extract treatment solution are simultaneously or sequentially subjected to ultrasonic treatment and microwave treatment to achieve synergistic enzyme inactivation and color protection. S4. Drain the fresh-cut medicinal materials that have undergone synergistic enzyme inactivation and color protection treatment, and then dry them until the preset moisture content is reached.

2. The synergistic treatment process for fresh-cut stem medicinal materials according to claim 1, characterized in that, In step S2, the natural polyphenol antioxidant complex in the compound natural extract treatment solution is selected from one or more of green tea extract, bamboo leaf extract, rosemary extract, and grape seed extract, and its total polyphenol mass concentration in the treatment solution is 0.2-2.0%.

3. The synergistic treatment process for fresh-cut stem medicinal materials according to claim 1, characterized in that, In step S2, the natural organic acid or enzyme activity regulator in the compound natural extract treatment solution is selected from one or more combinations of citric acid, L-ascorbic acid, L-ascorbyl palmitate, and phytic acid, and its total mass concentration in the treatment solution is 0.1-1.5%, and the pH value of the treatment solution is adjusted to the range of 3.5-5.

5.

4. The synergistic treatment process for fresh-cut stem medicinal materials, enzyme inactivation, and color protection according to claim 1, is characterized in that, The composite natural extract treatment solution in step S2 also contains a natural penetration enhancer or film-forming agent, selected from one or more combinations of tea saponin extract, soapberry saponin extract, low molecular weight chitosan, and sodium alginate, with a total mass concentration of 0.01-0.5% in the treatment solution.

5. The synergistic treatment process for fresh-cut stem medicinal materials according to claim 1, characterized in that, The ultrasonic treatment in step S3 operates at a frequency of 20-60kHz, a power density of 50-300W / L, and a duration of 2-10 minutes.

6. The synergistic treatment process for fresh-cut stem medicinal materials, enzyme inactivation, and color protection according to claim 1, is characterized in that, The microwave treatment in step S3 raises the temperature of the treatment liquid and fresh-cut medicinal materials to the target enzyme-inactivating temperature of 50-75°C within 2-8 minutes, and maintains this temperature for 2-10 minutes.

7. The synergistic treatment process for fresh-cut stem medicinal materials according to claim 1, characterized in that, In step S3, ultrasonic treatment and microwave treatment are performed simultaneously, or microwave treatment is performed after ultrasonic pretreatment, or the two are performed alternately.

8. The synergistic treatment process for fresh-cut stem medicinal materials, enzyme inactivation, and color protection according to claim 1, is characterized in that, The total combined processing time for ultrasonic and microwave treatments in step S3 is 3-20 minutes.

9. The synergistic treatment process for fresh-cut stem medicinal materials, enzyme inactivation, and color protection according to claim 1, is characterized in that, In step S1, the thickness of the freshly cut medicinal materials is 2.0-10.0 mm or the length of the segments is 1.0-5.0 cm.

10. The synergistic treatment process for fresh-cut stem medicinal materials, enzyme inactivation, and color protection according to claim 1, is characterized in that, The interval between immersion in the treatment solution in step S2 is controlled within 2-10 minutes.

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