Quality control method for processing process of nine-processed rhizoma polygonati

Abstract

The invention relates to the technical field of quality control of a traditional Chinese medicine processing process, in particular to a quality control method of a nine-processed rhizoma polygonati processing process, which comprises the following steps: A, sample preparation, B, element analysis, C, electrochemical analysis, D, thermogravimetric analysis and E, data analysis. According to the method, a quantitative correlation model between processing times and parameters is established through collaborative application of three technologies of elemental analysis, electrochemical analysis and thermogravimetric analysis, so that scientific, objective and dynamic quality control and end point judgment of the processing process of the nine-processed rhizoma polygonati are realized, the quality control efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of traditional Chinese medicine quality control technology, specifically involving a method for dynamic monitoring and endpoint determination of the nine-processed Polygonatum odoratum processing method based on multi-dimensional analysis technology. Background Technology

[0002] According to the 2020 edition of the Chinese Pharmacopoeia, the Chinese medicinal herb Polygonatum is the dried rhizome of Polygonatum kingianum Coll. et Hemsl., Polygonatum sibiricum Red., or Polygonatum cyrtonema Hua, all belonging to the Liliaceae family. Depending on its shape, it is commonly known as large Polygonatum, chicken-head Polygonatum, or ginger-shaped Polygonatum. It is harvested in spring and autumn, the fibrous roots are removed, it is washed, and it is briefly blanched in boiling water or steamed until thoroughly cooked before drying. Polygonatum has the effects of replenishing qi and nourishing yin, strengthening the spleen, moistening the lungs, and benefiting the kidneys. In March 2002, the former Ministry of Health issued a list of items that are both food and medicine, and Polygonatum was included in it. However, raw Polygonatum contains a lot of calcium oxalate crystals, and direct consumption can cause numbness of the mouth and tongue and irritation of the throat. Therefore, Polygonatum should not be used directly in its raw form, and the Polygonatum used in production and daily life is all processed products. According to ancient records, the processing of Polygonatum sibiricum began during the Liu Song Dynasty of the Southern Dynasties (420-479 AD). The Tang Dynasty text *Dietary Therapy Materia Medica* first proposed the nine-steaming and nine-drying method for Polygonatum sibiricum, thus establishing the initial processing technique that has been used ever since. However, the current process control of the nine-steaming and nine-drying method relies heavily on the experience and sensory judgment of the processors, lacking scientific rigor and rationality, resulting in significant batch-to-batch quality variations in the final product. Currently, the quality control methods for processed Polygonatum sibiricum mainly include the following categories: (1) Chemical composition-based analytical methods: such as the quality evaluation methods for processed Polygonatum sibiricum disclosed by Zhang Xiaoyan et al. (CN116370572 A), Li Mengen et al. (Shizhen Guoyi Guoyao, Vol. 32, No. 8, 2021, pp. 1897-1900), and Hu Changjiang et al. (CN201810690896.9), which use high performance liquid chromatography to determine the content of 5-hydroxymethylfurfural (5-HMF), polysaccharides, and monosaccharides, and combine image analysis technology to determine the total color value. Although these methods can reflect some changes in chemical composition, the sample pretreatment is complicated and the detection time is long (usually several hours), which cannot meet the needs of rapid and continuous monitoring at the processing site. At the same time, a single component index cannot fully reflect the complex material transformation and structural changes during the processing process; (2) Experience-based judgment method based on sensory characteristics: such as DB4203 / T 239-2024 "Technical Specification for Nine Steaming and Nine Drying Processing of Polygonatum", which mainly relies on the processor's experience and senses to make judgments, lacks scientificity and objectivity, and has large differences in quality between batches; (3) Analytical methods based on polysaccharide components: For example, Zhang Fan et al. (Modern Food Science and Technology, Vol. 38, No. 9, 2022, pp. 171-180) used size exclusion gel chromatography and ion chromatography to analyze the molecular weight distribution and monosaccharide composition of polysaccharides. This method focuses on the analysis of polysaccharide structure and fails to fully reflect the changes in elemental composition and thermodynamic properties during the processing. In summary, the existing technologies have the following shortcomings: (1) lack of systematic research on changes in elemental composition during processing; (2) lack of rapid and convenient electrochemical detection methods; (3) lack of dynamic monitoring methods for processing based on thermal analysis technology; (4) lack of correlation analysis methods for multidimensional analysis parameters; (5) limitations of existing electrochemical detection technologies: existing technologies mainly include two categories: ① quantitative detection of polysaccharides based on molecular imprinted sensors (such as CN202510970576.9), which requires the preparation of AC-COOH-PANI composite material modified electrodes, and only designs highly selective recognition interfaces for a single known target (such as polysaccharides), which belongs to endpoint quantitative detection, and the electrode modification process is complex, costly, and has low universality; ② electrochemical fingerprint spectrum identification based on BZ oscillation reaction (Wang Yuanyuan et al., 2019, Chemical Reagents), which uses the difference in oscillation waveforms to identify the place of origin or type, and the signal is the oscillation period / amplitude in the time domain, which belongs to "static" fingerprint comparison, and cannot analyze the quantitative relationship with the continuous change of the number of processing times.

[0003] The methods mentioned above have failed to solve the problem of real-time quality control during the nine-times-processed Polygonatum odoratum. Therefore, there is an urgent need for a quality control method that can reflect the dynamic changes in material composition and structure during the nine-times-processed Polygonatum odoratum in real time, quickly and comprehensively, and link multi-source information to achieve objective judgment of the processing process and precise control of the endpoint. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a quality control method for the nine-times-processed Polygonatum sibiricum processing process. By synergistically applying elemental analysis, electrochemical analysis, and thermogravimetric analysis, the method achieves scientific, objective, and dynamic quality control and endpoint determination of the nine-times-processed Polygonatum sibiricum processing process.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a quality control method for the nine-stage processing of Polygonatum sibiricum, comprising the following steps: A. Sample preparation steps: Take the rhizome of Polygonatum sibiricum, clean it, and process it through nine steaming and nine sun-drying processes to prepare 10 groups of samples, including raw Polygonatum sibiricum, one-time processed Polygonatum sibiricum to nine-time processed Polygonatum sibiricum; B. Elemental analysis procedure: Place each group of sample powders in an elemental analyzer, using helium as the carrier gas and oxygen as the combustion gas, to determine the content of the five elements: carbon, hydrogen, nitrogen, sulfur, and oxygen. C. Electrochemical analysis procedure: Mix the sample powders of each group with the acidic cerium-malonic acid system, pre-react in a constant temperature water bath at 35-40℃ for 20-40 min, then add bromate solution to start the reaction. Under magnetic stirring, use differential pulse voltammetry to scan and record the electrochemical response curve, and extract the oxidation peak potential and peak current values ​​as characteristic parameters; wherein, the acidic cerium-malonic acid system is composed of sulfuric acid, cerium ammonium sulfate, and malonic acid, and the mass-volume ratio of sample powder to system is 1:200-1:300 g / mL; D. Thermogravimetric analysis procedure: Simultaneous thermogravimetric-differential scanning calorimetry was performed on the powder samples of each group in the range of room temperature to 800℃, with nitrogen as the carrier gas and a heating rate of 10℃ / min. The total weight loss rate, the weight loss rate in the low temperature region of 30 to 200℃, the weight loss rate in the medium temperature region of 200 to 400℃, the residual rate above 400℃, and the decomposition peak temperature were determined. E. Data Analysis Steps: Multivariate statistical methods are used to conduct correlation analysis between the number of processing steps and element content, electrochemical oxidation peak current value, and thermogravimetric parameters. A quantitative correlation model is established between the number of processing steps and the element content, electrochemical oxidation peak current value, and thermogravimetric parameters. Based on this model, the processing process is dynamically evaluated and the endpoint is determined.

[0006] Furthermore, the nine-step processing method for Polygonatum sibiricum specifically includes the following steps: S1. Cleaning: Take the rhizome of Polygonatum sibiricum, remove impurities and fibrous roots, place it in a drum washing machine and rinse it repeatedly, spread it out to dry until the texture softens, and rinse the surface dust again with clean water; S2. Steaming: Steam the washed and air-dried raw Polygonatum in a water bath. Cover the pot while steaming and heat it over high heat at 150-220℃ until steam rises in the pot. Then, reduce the heat to low heat at 80-120℃ and steam continuously for 8 hours. Add water as needed during the steaming process to ensure that the bottom water does not dry out. S3. Stewing and Drying: After steaming, stop heating and stew for 10 hours using the residual heat in the pot until the color of the Polygonatum turns yellowish-brown. Remove it, place it on a clean baking tray, and dry it in a 60℃ hot air circulating drying oven for 6 hours. Let it cool overnight to complete the first steaming and obtain one batch of Polygonatum. S4. Cyclic processing: Before the second to ninth steaming, spray water to moisten the surface of the Polygonatum sibiricum. Repeat the steaming and simmering process of step S2 and the drying process of step S3 for a total of 8 times. After the ninth steaming, let it cool directly, cut it into thin slices, and dry it in a 60℃ hot air circulating drying oven to constant weight to obtain the finished product of nine-times processed Polygonatum sibiricum.

[0007] Furthermore, the specific conditions for the elemental analysis are as follows: Sample pretreatment: The sample was dried at 40℃ for 8 hours, at 50℃ for 8 hours, and at 60℃ to constant weight, then pulverized and passed through a 60-100 mesh sieve; Instrument conditions: Helium was used as the carrier gas and oxygen as the combustion gas to determine the content of five elements: carbon, hydrogen, nitrogen, sulfur, and oxygen. The results are expressed as weight percentages.

[0008] Furthermore, the specific conditions for the electrochemical analysis are as follows: Sample pretreatment: Pass the Polygonatum odoratum powder through a 60-100 mesh sieve and dry it at 40-60℃ to constant weight; Detection conditions: constant temperature 35-39℃, magnetic stirring speed 400-600 r / min, pre-reaction time 25-35 min, using a three-electrode system, in which the working electrode is a glassy carbon electrode, the counter electrode is a platinum wire electrode, and the reference electrode is a saturated calomel electrode; Reagent ratio: 0.08-0.12g of Polygonatum sibiricum powder, 12mL of 2.5-3.5mol / L sulfuric acid solution, 3.0mL of 0.004-0.006mol / L cerium ammonium sulfate solution, 6.0mL of 0.35-0.45mol / L malonic acid solution, and 3.0mL of 0.15-0.25mol / L sodium bromate solution; Measurement method: Differential pulse voltammetry was used, with a scanning potential range of 0.5 to 1.5 V, a pulse amplitude of 0.05 V, a pulse width of 0.05 s, a sampling interval of 0.02 s, and a sensitivity of 0.001 A / V. The oxidation peak potential and peak current values ​​were recorded.

[0009] Furthermore, the specific conditions for the thermogravimetric analysis are as follows: Temperature range: room temperature to 800℃; Heating rate: 10℃ / min; Carrier gas: Nitrogen; Measurement parameters: TG curve, DTG curve, DSC curve; Key indicators: total weight loss rate, weight loss rate in the low temperature range of 30–200℃, weight loss rate in the medium temperature range of 200–400℃, residual rate above 400℃, and main decomposition peak temperature.

[0010] Furthermore, the elemental index judgment criteria for the final processing point of the nine-times processed Polygonatum are: carbon content ≥ 42%, nitrogen content ≥ 2.0%, and sulfur content ≤ 0.15%.

[0011] Furthermore, the electrochemical index judgment standard for the processing endpoint is: the current value of the first oxidation peak ≤ 1.8 × 10⁻ 4 A, and the potential value of the first oxidation peak is in the range of 0.10 to 0.13V.

[0012] Furthermore, the criteria for judging the thermogravimetric index at the end of the processing are: residual mass at 200℃ ≥ 60%, total weight loss ≤ 72%, and residual rate above 400℃ ≥ 34%.

[0013] Furthermore, the Spearman rank correlation coefficient r ≤ -0.85 between the number of processing times and the first oxidation peak current value and total weight loss rate.

[0014] Furthermore, the multivariate statistical methods include Pearson correlation analysis, Spearman rank correlation analysis, and linear regression analysis. The multivariate statistical methods are as follows: (1) Pearson correlation analysis: Analyze the linear correlation between the number of processing times and the content of each element, electrochemical parameters, and thermogravimetric parameters; (2) Spearman rank correlation analysis: The monotonic correlation between the number of processing times and each parameter was analyzed, and P<0.05 was used to indicate that the difference was statistically significant; (3) Linear regression analysis: Establish a quantitative relationship model between the number of processing times and each parameter.

[0015] The beneficial effects of this invention are as follows: This invention effectively achieves scientific, objective, and dynamic quality control over the nine-stage processing of Polygonatum sibiricum through the synergistic application of elemental analysis, electrochemical analysis, and thermogravimetric analysis, thereby improving quality control efficiency and reducing costs. Specific effects include: (1) Innovative analytical methods: For the first time, DPV analysis based on the acidic cerium-malonic acid-bromate system was introduced into the dynamic monitoring of the nine-times processed Polygonatum odoratum processing process, filling the gap in rapid and in-situ detection technology in this field.

[0016] (2) System innovation: A three-dimensional quality evaluation system of element-electrochemistry-thermogravimetric analysis was constructed, realizing cross-scale comprehensive evaluation from atomic composition and molecular reactivity to macroscopic thermal stability, overcoming the problem of the one-sidedness of single indicators.

[0017] (3) Standard innovation: For the first time, an objective judgment standard for the processing endpoint based on multidimensional parameters of elements, electrochemistry and thermogravimetrics was proposed, which enabled the traditional “nine steaming and nine drying” experience process to be digitized and standardized.

[0018] (4) Efficiency and cost advantages: Compared with methods such as HPLC, the detection time is greatly shortened (the electrochemical detection time is shortened from several hours to about 30 minutes), and no complicated pretreatment and expensive chromatographic columns are required, making it more suitable for online quality control in industrial production.

[0019] (5) The significant difference and progress of the present invention compared with the prior art is as follows: Compared with Zhang Xiaoyan et al. (CN116370572 A, HPLC method): This invention is the first to construct a three-dimensional analysis system of element-electrochemical-thermogravimetric analysis, which does not require complex chromatographic pretreatment, is more comprehensive and systematic, and shortens the detection time by more than 60%, making it suitable for online quality control in industrial production; Compared with the Polygonatum polysaccharide electrochemical sensor (CN202510970576.9): This patent uses a molecularly imprinted sensor to modify the electrode for polysaccharide detection, which requires the preparation of AC-COOH-PANI composite material, making the operation complex and costly, and it only targets a single polysaccharide component; This invention uses nonlinear oscillation-DPV coupled technology, which does not require electrode modification, and directly utilizes the liquid-phase reaction between Polygonatum powder and the reagent system to achieve simultaneous detection of multiple components through DPV scanning. It is simple to operate, low in cost, and has different detection principles, application scenarios, and technical characteristics. Compared with the BZ oscillation fingerprint spectrum of Polygonatum multiflorum (Wang Yuanyuan et al., 2019): that literature uses BZ oscillation reaction to record oscillation period parameters for origin identification, while this invention uses a similar reagent system but a completely different signal acquisition and analysis method - using DPV scanning to record oxidation peak potential and current dual indicators for quality control of the nine-steaming and nine-drying processing process. The two are fundamentally different in the detection purpose "origin identification corresponds to processing monitoring", the signal type "oscillation period corresponds to oxidation peak current / potential", and the data analysis dimension "fingerprint similarity corresponds to the quantitative correlation of processing times and electrochemical response". Compared with DB 4203 / T 239-2024, this invention uses instrumental analysis to replace sensory judgment, thereby improving scientific rigor and objectivity.

[0020] Compared with Zhang Fan et al. (Modern Food Science and Technology, 2022), this invention focuses on the variation law of elemental composition and thermodynamic properties, rather than the analysis of polysaccharide structure. Attached Figure Description

[0021] Figure 1 A schematic diagram illustrating the preparation process and quality control of processed Polygonatum sibiricum; Figure 2 Photographs of Polygonatum sibiricum powder samples after different processing times (nine-times processed); Figure 3 This is a diagram showing the elemental composition of Polygonatum sibiricum processed under different processing times in Example 2; Figure 4 The graph shows the thermogravimetric analysis results of Polygonatum sibiricum processed under different processing times in Example 2; Figure 5 The graph shows the electrochemical analysis results of Polygonatum sibiricum processed under different processing times in Example 2; where curves 1 to 10 represent raw Polygonatum sibiricum and Polygonatum sibiricum processed once to nine times, respectively. Detailed Implementation

[0022] The following will combine Figures 1 to 5 As shown, the technical solution of the present invention will be clearly and completely described.

[0023] Example 1, see Figure 2 The preparation of nine-times processed Polygonatum is shown below: Take 10.0 kg of Polygonatum rhizome tubers, remove impurities and fibrous roots, place them in a drum washing machine and rinse them repeatedly until clean. Spread them out to soften, and rinse the surface dust again with clean water. Steam the washed and air-dried raw Polygonatum rhizome in a water bath. Cover the pot and steam over high heat (150-220℃) to create a circular steam pattern. Then reduce the heat to low (80-120℃) and steam continuously for 8 hours. Add water as needed during the steaming process to ensure the bottom water does not dry out. After steaming, stop heating immediately and let it simmer for 10 hours using the residual heat in the pot until the color of the Polygonatum turns yellowish-brown. Remove it, place it on a clean baking tray, and dry it in a 60℃ hot air circulating drying oven for 6 hours. Let it cool overnight to complete the first steaming process and obtain one batch of Polygonatum. Spray with water to moisten before the second to ninth steaming. Repeat the steaming, simmering and drying process a total of 8 times. After the ninth steaming, let it cool directly, cut it into thin slices with a medicine cutter, and then dry it in a 60℃ hot air circulating drying oven until dry to obtain the nine-times processed Polygonatum product. After the first to ninth evaporation and drying, 500g of samples were randomly selected for elemental analysis, electrochemical analysis and thermogravimetric analysis.

[0024] Example 2, see Figures 3 to 5 The multidimensional analysis detection shown: (a) Elemental Analysis The raw Polygonatum and the processed Polygonatum samples (one to nine) were cut into thin slices and dried in a forced-air drying oven at 40°C for 8 hours, 50°C for 8 hours, and 60°C until there was no water and the powder could be easily crushed by light tapping. The powder was then passed through an 80-mesh sieve to obtain 10 sample powders. The Vario EL cube elemental analyzer was used with helium as the carrier gas and oxygen as the combustion gas to determine the content of five elements: carbon, hydrogen, nitrogen, sulfur, and oxygen. The test results show that: with the increase of processing times, the carbon content first decreased and then increased, reaching the highest value of 43.30% at the seventh processing stage; the hydrogen content fluctuated; the nitrogen content increased significantly from the fourth to the seventh processing stage; the sulfur content generally decreased; and the oxygen content generally increased and then decreased. Correlation analysis results: Carbon and oxygen are negatively correlated, i.e., ρ=-0.891, p=0.001; nitrogen and sulfur are positively correlated, i.e., ρ=0.6848, p=0.0289; nitrogen and oxygen are negatively correlated, i.e., ρ=-0.8061, p=0.0049.

[0025] (II) Differential pulse voltammetric electrochemical analysis based on nonlinear chemical oscillation system The CHI660E electrochemical analyzer was used, equipped with a three-electrode system, in which the working electrode was glassy carbon, the counter electrode was platinum wire, and the reference electrode was saturated calomel. The temperature was kept constant at 37℃ and the magnetic stirring speed was 500 r / min. Reagent ratio: 0.1g Polygonatum sibiricum powder, 12mL 3mol / L sulfuric acid solution, 3.0mL 0.005mol / L cerium ammonium sulfate solution, 6.0mL 0.4mol / L malonic acid solution, 3.0mL 0.2mol / L sodium bromate solution; Experimental steps: (1) Pre-reaction stage: Mix Polygonatum powder with sulfuric acid solution, cerium ammonium sulfate solution and malonic acid solution, and pre-react in a constant temperature water bath at 37℃ for 30 min to allow the sample and system to fully react; (2) Reaction start-up stage: Add sodium bromate solution and equilibrate for 5 min under magnetic stirring; (3) DPV scanning stage: Under magnetic stirring conditions, differential pulse voltammetry was used with the following parameters: scanning potential range -0.5V~1.5V, pulse amplitude 0.05V, pulse width 0.05s, sampling interval 0.02s, and sensitivity 0.001A / V. After optimization experiments, the above DPV parameters can clearly distinguish the characteristic oxidation peaks of Polygonatum sibiricum sample in the system while ensuring the signal-to-noise ratio. (4) Data acquisition stage: Record the oxidation peak potential and peak current values; First oxidation peak: The potential value is stable between 0.10 and 0.13V, with 0.124V for raw product and 0.124V for processed product. The current value ranges from 5.009 × 10⁻⁻⁻⁴ for raw Polygonatum. 4 A decreased to 1.736 × 10⁻ of the nine-processed Polygonatum. 4 A, a decrease of approximately 65%; The second oxidation peak: the potential value is stable at 1.24–1.25 V, and the current value fluctuates, with the value of raw Polygonatum being 1.922 × 10⁻⁻⁻⁶. 4 A, Nine-times processed Polygonatum sibiricum 1.175 × 10⁻ 5 A, a decrease of 94%.

[0026] Correlation analysis results: The number of processing times was significantly negatively correlated with the current value of peak 1 (r = -0.92, p < 0.001); the number of processing times was significantly negatively correlated with the current value of peak 2 (r = -0.85, p = 0.002); the number of processing times was not significantly correlated with the potential value of peak 1 (p > 0.05), indicating that the potential value can be used as a reference indicator for the stability of the system.

[0027] Example 3: Determination of the endpoint of nine-times processed Polygonatum sibiricum: A batch of processed Polygonatum sibiricum products were taken and subjected to multidimensional analysis and testing according to the method in Example 2. The test results are as follows: Carbon content: 42.8%; Nitrogen content: 2.15%; Sulfur content: 0.13%; First oxidation peak current value: 1.8 × 10⁻ 4A; First oxidation peak potential: 0.124V; Residual mass at 200℃: 62%; Total weight loss: 70%; Residual rate above 400℃: 32%.

[0028] Compare the above test results with the criteria for determining the endpoint of processing: Carbon content ≥ 42.8%, meets the standard; nitrogen content ≥ 2.0%, meets the standard; sulfur content ≤ 0.15%, meets the standard; first oxidation peak potential value ≥ 0.124V within the range of 0.10~0.13V, meets the standard; residual mass at 200℃ ≥ 60%, meets the standard; total weight loss ≤ 72%, meets the standard; residual rate at 400℃ ≥ 30%, meets the standard. Among the above judgment criteria, the strong negative correlation between the electrochemical oxidation peak current value and the number of processing times, i.e., r ≤ -0.85, is the core dynamic monitoring indicator, while element content and thermogravimetric parameters serve as important auxiliary verification and endpoint confirmation indicators. Conclusion: Based on the above multi-dimensional indicators, this batch of processed Polygonatum sibiricum products has met the nine-stage endpoint quality requirements defined in this invention.

[0029] The working principle of this invention is as follows: See Figure 1 As shown, this invention is not a simple combination or parameter adjustment of existing technologies, but rather a completely different technical path chosen to solve the specific technical problem of "dynamic quality control in the processing of Polygonatum sibiricum". DPV scanning was used, and a data analysis model based on multivariate statistics was established, namely a quantitative correlation model. Therefore, through the synergistic application of elemental analysis, electrochemical analysis and thermogravimetric analysis, scientific, objective and dynamic quality control of the nine-times-processed Polygonatum sibiricum can be effectively achieved, thereby improving quality control efficiency and reducing costs.

[0030] This invention uses a reagent combination similar to the BZ oscillation system, but innovatively adopts the DPV scanning method to collect dual indicators of oxidation peak current and potential instead of recording oscillation period parameters, thereby realizing dynamic monitoring of the processing process. It differs fundamentally from existing technologies in terms of detection purpose, signal acquisition method and data analysis dimension (as shown in Table 1 below). It uses objective instrument data to replace subjective sensory judgment to solve the industry pain point of large batch differences.

[0031] To more clearly demonstrate the innovativeness of this invention, a comparison between this invention and the closest existing electrochemical analysis technique is listed in Table 1:

[0032] Furthermore, this invention utilizes the differences in reducing power of various electroactive substances (such as phenols, reducing sugars, amino acids, and their Maillard reaction products) in the acidic cerium-malonic acid-bromate classical nonlinear chemical oscillation system within Polygonatum powder. Using DPV technology, with high sensitivity and resolution, it selectively scans and records the oxidation current of these substances at specific potentials. During the processing of Polygonatum, as Maillard reactions and caramelization proceed, small-molecule reducing sugars, amino acids, and other electroactive precursors are continuously consumed and transformed into inert products such as macromolecular melanin, leading to a regular and unidirectional decay of the overall reducing power of the sample. By capturing this decay process with high sensitivity using DPV, the oxidation peak current value is used as a comprehensive electrochemical activity index characterizing the processing depth, achieving continuous and quantitative tracking of the processing process.

[0033] This invention made an important discovery when using multivariate statistical methods to analyze the correlation between the number of processing times of Polygonatum and elemental content, electrochemical oxidation peak current value, and thermogravimetric parameters: (1) The variation pattern of element composition: The elements are five core elements: C, H, N, S and O. The C content shows a trend of "decreasing in the first three processes, reaching the lowest level in the fourth and fifth processes, rebounding in the seventh to ninth processes, and reaching the highest value of 43.30% in the seventh process". The N content increases significantly from the fourth to the seventh process. The S content shows an overall decreasing trend. The O content first increases and then decreases. Carbon and oxygen are negatively correlated, i.e., ρ=-0.891, p=0.001. Nitrogen and sulfur are positively correlated, i.e., ρ=0.6848, p=0.0289. This pattern serves as a characteristic marker of the processing process. (2) Changes in electrochemical fingerprint characteristics: The current value of the first oxidation peak decreased significantly with the increase of the number of processing times, with the value of raw Polygonatum sibiricum being 5.009×10⁻ 4 A, Nine-times processed Polygonatum sibiricum 1.736 × 10⁻ 4 A, a decrease of 65%, the current value of the second oxidation peak showed fluctuating changes, namely, 1.922×10⁻ for raw Polygonatum. 4 A, Nine-times processed Polygonatum sibiricum 1.175 × 10⁻ 5 A. The first oxidation peak potential value is stable in the range of 0.10 to 0.13 V, indicating that the redox characteristics of the main electroactive substances remain consistent. This suggests that the content of electroactive components decreases or is transformed into non-electroactive substances during the processing. Moreover, the dual indicators of potential and current are more reflective of the stability of the processing process than the single current indicator. The electrochemical stability of the system is enhanced in the later stage of processing, and the monotonicity of the current value decreases significantly, providing a stable and easily measurable quantitative scale for the processing process. (3) Changes in thermal stability: The number of processing times is significantly negatively correlated with the total weight loss, i.e., r=-0.8788, p=0.0008, and the number of processing times is significantly positively correlated with the residual weight, i.e., r=0.8788, p=0.0008. As the number of processing times increases, the weight loss rate in the low temperature zone (30-200℃) decreases from 25% for raw products to 15.2% for processed products, while the weight loss rate in the medium temperature zone (200-400℃) increases from 45% to 55.6%, and the residual rate above 400℃ increases from 5% to 34.17%. The significant increase in the thermogravimetric residual rate directly confirms from a thermodynamic perspective the formation of carbon-like structures or stable macromolecular networks in the later stages of processing, which corresponds to the traditional experience that "the medicinal properties become warmer after nine processing times".

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalent substitutions, improvements, etc., made within the technical concept of the present invention should be included within the protection scope of the present invention.

Claims

1. A quality control method for the nine-stage processing of Polygonatum odoratum, characterized in that: Includes the following steps: A. Sample preparation steps: Take the rhizome of Polygonatum sibiricum, clean it, and process it through nine steaming and nine sun-drying processes to prepare 10 groups of samples, including raw Polygonatum sibiricum, one-time processed Polygonatum sibiricum to nine-time processed Polygonatum sibiricum; B. Elemental analysis procedure: Place each group of sample powders in an elemental analyzer, using helium as the carrier gas and oxygen as the combustion gas, to determine the content of the five elements: carbon, hydrogen, nitrogen, sulfur, and oxygen. C. Electrochemical analysis procedure: Mix the sample powders of each group with the acidic cerium-malonic acid system, pre-react in a constant temperature water bath at 35-40℃ for 20-40 min, then add bromate solution to start the reaction. Under magnetic stirring, use differential pulse voltammetry to scan and record the electrochemical response curve, and extract the oxidation peak potential and peak current values ​​as characteristic parameters; wherein, the acidic cerium-malonic acid system is composed of sulfuric acid, cerium ammonium sulfate, and malonic acid, and the mass-volume ratio of sample powder to system is 1:200-1:300 g / mL; D. Thermogravimetric analysis procedure: Simultaneous thermogravimetric-differential scanning calorimetry was performed on the powder samples of each group in the range of room temperature to 800℃, with nitrogen as the carrier gas and a heating rate of 10℃ / min. The total weight loss rate, the weight loss rate in the low temperature region of 30 to 200℃, the weight loss rate in the medium temperature region of 200 to 400℃, the residual rate above 400℃, and the decomposition peak temperature were determined. E. Data Analysis Steps: Multivariate statistical methods are used to conduct correlation analysis between the number of processing steps and element content, electrochemical oxidation peak current value, and thermogravimetric parameters. A quantitative correlation model is established between the number of processing steps and the element content, electrochemical oxidation peak current value, and thermogravimetric parameters. Based on this model, the processing process is dynamically evaluated and the endpoint is determined.

2. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The nine-step processing method for Polygonatum sibiricum specifically includes the following steps: S1. Cleaning: Take the rhizome of Polygonatum sibiricum, remove impurities and fibrous roots, place it in a drum washing machine and rinse it repeatedly, spread it out to dry until the texture softens, and rinse the surface dust again with clean water; S2. Steaming: Steam the washed and air-dried raw Polygonatum in a water bath. Cover the pot while steaming and heat it over high heat at 150-220℃ until steam rises in the pot. Then, reduce the heat to low heat at 80-120℃ and steam continuously for 8 hours. Add water as needed during the steaming process to ensure that the bottom water does not dry out. S3. Stewing and Drying: After steaming, stop heating and stew for 10 hours using the residual heat in the pot until the color of the Polygonatum turns yellowish-brown. Remove it, place it on a clean baking tray, and dry it in a 60℃ hot air circulating drying oven for 6 hours. Let it cool overnight to complete the first steaming and obtain one batch of Polygonatum. S4. Cyclic processing: Before the second to ninth steaming, spray water to moisten the surface of the Polygonatum sibiricum. Repeat the steaming and simmering process of step S2 and the drying process of step S3 for a total of 8 times. After the ninth steaming, let it cool directly, cut it into thin slices, and dry it in a 60℃ hot air circulating drying oven to constant weight to obtain the finished product of nine-times processed Polygonatum sibiricum.

3. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The specific conditions for the elemental analysis are as follows: Sample pretreatment: The sample was dried at 40℃ for 8 hours, at 50℃ for 8 hours, and at 60℃ to constant weight, then pulverized and passed through a 60-100 mesh sieve; Instrument conditions: Helium was used as the carrier gas and oxygen as the combustion gas to determine the content of five elements: carbon, hydrogen, nitrogen, sulfur, and oxygen. The results are expressed as weight percentages.

4. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The specific conditions for the electrochemical analysis are as follows: Sample pretreatment: Pass the Polygonatum odoratum powder through a 60-100 mesh sieve and dry it at 40-60℃ to constant weight; Detection conditions: constant temperature 35-39℃, magnetic stirring speed 400-600 r / min, pre-reaction time 25-35 min, using a three-electrode system, in which the working electrode is a glassy carbon electrode, the counter electrode is a platinum wire electrode, and the reference electrode is a saturated calomel electrode; Reagent ratio: 0.08-0.12g of Polygonatum sibiricum powder, 12mL of 2.5-3.5mol / L sulfuric acid solution, 3.0mL of 0.004-0.006mol / L cerium ammonium sulfate solution, 6.0mL of 0.35-0.45mol / L malonic acid solution, and 3.0mL of 0.15-0.25mol / L sodium bromate solution; Measurement method: Differential pulse voltammetry was used, with a scanning potential range of 0.5 to 1.5 V, a pulse amplitude of 0.05 V, a pulse width of 0.05 s, a sampling interval of 0.02 s, and a sensitivity of 0.001 A / V. The oxidation peak potential and peak current values ​​were recorded.

5. The quality control method for the nine-stage processing of Polygonatum sibiricum as described in claim 1, characterized in that, The specific conditions for the thermogravimetric analysis are as follows: Temperature range: room temperature to 800℃; Heating rate: 10℃ / min; Carrier gas: Nitrogen; Measurement parameters: TG curve, DTG curve, DSC curve; Key indicators: total weight loss rate, weight loss rate in the low temperature range of 30–200℃, weight loss rate in the medium temperature range of 200–400℃, residual rate above 400℃, and main decomposition peak temperature.

6. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The elemental index criteria for judging the endpoint of the nine-processing of Polygonatum odoratum are as follows: Carbon content ≥42%, nitrogen content ≥2.0% and sulfur content ≤0.15%.

7. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The criteria for judging the electrochemical indicators at the end of the processing are as follows: The current value of the first oxidation peak is ≤1.8×10⁻ 4 A, and the potential value of the first oxidation peak is in the range of 0.10 to 0.13V.

8. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that, The criteria for judging the thermogravimetric index at the end of the processing are as follows: The residual mass at 200℃ is ≥60%, the total weight loss is ≤72%, and the residual rate above 400℃ is ≥34%.

9. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that: The criteria for judging the correlation index of the processing endpoint are as follows: The Spearman rank correlation coefficient r between the number of processing steps and the first oxidation peak current value and total weight loss rate is ≤ -0.

85.

10. The quality control method for the nine-stage processing of Polygonatum odoratum as described in claim 1, characterized in that: The multivariate statistical methods include Pearson correlation analysis, Spearman rank correlation analysis, and linear regression analysis.

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