Prepared rehmannia root charcoal processing technology optimization method

Abstract

The invention relates to the field of traditional Chinese medicines, in particular to a charred prepared rehmannia root processing technology optimization method which comprises the following steps: stir-frying prepared rehmannia roots at different temperatures and time to obtain charred prepared rehmannia roots; the method comprises the following steps: respectively taking the stir-frying temperature and stir-frying time of prepared rehmannia root charcoal as single factor variables, taking the content of 5-hydroxymethylfurfural and isoacteoside in the prepared rehmannia root charcoal as evaluation indexes, calculating a comprehensive score, and further determining a processing temperature optimization range and a processing time optimization range according to a calculation result of the comprehensive score; the further determined processing temperature optimization range and processing time optimization range are used as independent variables, the comprehensive score of the content of 5-hydroxymethylfurfural and the content of isoacteoside in the prepared rehmannia root charcoal is used as a response value, response surface test design is carried out, the prepared rehmannia root charcoal processing technology is further optimized, the optimal processing time and processing temperature are obtained, and the optimal processing temperature is obtained. The optimized prepared rehmannia root charcoal process is safe and effective, and a basis is provided for quality control of the prepared rehmannia root charcoal.

Description

Technical Field

[0001] The present invention relates to the field of traditional Chinese medicine, and in particular to a method for optimizing the processing technology of Rehmannia glutinosa charcoal. Background Art

[0002] Rehmannia glutinosa Rehmannia glutinosa Fresh or dried root tubers of Libosch. Rehmannia root, also known as Rehmannia glutinosa, is a processed product of Rehmannia root. Processing alters its chemical composition, which in turn changes its medicinal properties. Rehmannia root is sweet and slightly warm in nature. It enters the liver and kidney meridians, nourishing blood and yin, and replenishing essence and marrow. Modern clinical treatments are indicated for conditions such as blood deficiency, sallow complexion, palpitations, irregular menstruation, metrorrhagia, liver and kidney yin deficiency, soreness of the waist and knees, hot flashes, night sweats and spermatorrhea, internal heat and thirst, dizziness, tinnitus, and premature graying of hair.

[0003] Rehmannia root has a long history of medicinal use, with records in Shennong's Herbal Classic, Jingyue Complete Works, and Illustrated Classic of Materia Medica. Prepared Rehmannia root contains numerous chemical components, primarily glycosides, furanaldehyde derivatives, sugars, amino acids, ionones, and various trace elements. It exhibits multiple pharmacological actions and is widely used clinically. Rehmannia root polysaccharides, among them, possess anti-anxiety properties. Rehmannia root and its processed products are commonly used in clinical practice. Due to its bitter and cold nature, Rehmannia root is processed using various methods to adapt to various patient conditions and individual differences, modifying the active ingredients and thereby modulating the medicinal properties, enhancing efficacy, and altering pharmacological and clinical efficacy.

[0004] Traditional Chinese Medicine (TCM) culture is a traditional Chinese culture; TCM preparation is a unique Chinese pharmaceutical technology. Since ancient times, various methods have been used to prepare Rehmannia root. In ancient times, methods included boiling, salt water preparation, safflower preparation, and nine-steaming and nine-drying. Rehmannia root has a complex composition and numerous preparation methods. Its chemical composition varies significantly before and after preparation. Clarifying the active ingredients and differences between different preparations is crucial for clinical use. Modern preparation techniques include wine cooking, charcoal stir-frying, and Amomum villosum preparation, but steaming and decoction are still the main methods. The processing endpoint is unclear, impacting the quality control of Rehmannia root carbon. Summary of the Invention

[0005] In view of the deficiencies in the above-mentioned prior art, the object of the present invention is to provide a method for optimizing the processing technology of Rehmannia glutinosa charcoal. The present invention takes Rehmannia glutinosa charcoal as the main research object, takes frying temperature and frying time as main considerations, takes 5-hydroxymethylfurfural and isocarpus glycoside content as main indicators, and performs content determination by high performance liquid chromatography. Through single-factor experiments, the processing temperature and processing time ranges are preliminarily inferred, and the response surface methodology is used to obtain the optimal processing temperature and processing time of Rehmannia glutinosa charcoal. Comprehensive analysis is performed to obtain the optimal processing temperature and optimal processing time of Rehmannia glutinosa charcoal. The preferred Rehmannia glutinosa charcoal process of the present invention is safe and effective, and provides a basis for quality control of Rehmannia glutinosa charcoal.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for optimizing the processing technology of Rehmannia glutinosa charcoal comprises the following steps: The Rehmannia glutinosa charcoal is crushed to obtain Rehmannia glutinosa charcoal powder, and verbascoside, isovalascoside and 5-hydroxymethylfurfural are extracted from the Rehmannia glutinosa charcoal to obtain verbascoside, isovalascoside and 5-hydroxymethylfurfural extracts.

[0007] Thermal analysis technology was used to study the pyrolysis characteristics of verbascoside, isovalascoside and 5-hydroxymethylfurfural extracts respectively. Based on the results of the pyrolysis characteristics study, the processing temperature range and processing time range of Rehmannia glutinosa charcoal were preliminarily obtained.

[0008] Based on the preliminary obtained processing temperature and processing time ranges of Rehmannia glutinosa charcoal, the contents of 5-hydroxymethylfurfural and isophylloside in Rehmannia glutinosa charcoal were calculated by high performance liquid chromatography. With the contents of 5-hydroxymethylfurfural and isophylloside as evaluation indicators, and processing temperature and processing time as single factor variables, a comprehensive score calculation was performed. According to the results of the comprehensive score calculation, the optimized range of processing temperature and the optimized range of processing time were further determined.

[0009] With the further determined optimized range of processing temperature and time as independent variables and the comprehensive score of 5-hydroxymethylfurfural and isocarpus glycoside content in Rehmannia glutinosa charcoal as the response value, a response surface experimental design was carried out to further optimize the processing process of Rehmannia glutinosa charcoal and obtain the optimal processing time and temperature.

[0010] In a preferred embodiment of the present invention, when preliminarily determining the processing temperature range and processing time range based on the pyrolysis characteristics results, the weight loss degree of 5-hydroxymethylfurfural and isocarpus glycoside components in Rehmannia glutinosa charcoal is used as the preliminarily optimized processing temperature range and processing time range of Rehmannia glutinosa charcoal.

[0011] In a preferred embodiment of the present invention, the pyrolysis characteristics are studied in the range of room temperature to 600°C.

[0012] In a preferred embodiment of the present invention, the initial processing temperature of Rehmannia glutinosa is 180° C. to 220° C., and the processing time is 10 min to 20 min.

[0013] In a preferred embodiment of the present invention, the further optimized processing temperature is 200°C to 220°C, and the processing time is 13min to 17min.

[0014] In a preferred embodiment of the present invention, the optimal processing temperature is 210°C and the processing time is 15 minutes.

[0015] In a preferred embodiment of the present invention, the response surface optimization experiment was performed using Design Expert 13.0 software according to the central composite design principle to obtain the quadratic multiple regression equation y = 0.8508 + 0.0112 * A - 0.0282 * B + 0.0054 * AB - 0.0125 * A 2 -0.0896*B 2 , where r 2 =0.9335, A represents the processing time, and B represents the processing temperature.

[0016] In a preferred embodiment of the present invention, the thermal analysis technique is thermogravimetric analysis and differential thermogravimetric analysis.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The invention takes Rehmannia glutinosa charcoal as the main research object, adopts thermal analysis technology to respectively study the pyrolysis characteristics of verbascoside, isovarascoside and 5-hydroxymethylfurfural extracts, and preliminarily obtains the processing temperature range and processing time range of Rehmannia glutinosa charcoal according to the pyrolysis characteristic research results; on the basis of the preliminarily obtained processing temperature and processing time range of Rehmannia glutinosa charcoal, calculates the content of 5-hydroxymethylfurfural and isovarascoside in Rehmannia glutinosa charcoal by high performance liquid chromatography, takes the content of 5-hydroxymethylfurfural and isovarascoside as evaluation indexes, and the processing temperature and processing time are A single-factor variable was used for comprehensive score calculation, and the optimal range of processing temperature and the optimal range of processing time were further determined based on the comprehensive score calculation results; with the further determined optimal range of processing temperature and the optimal range of processing time as independent variables, and the comprehensive score of the 5-hydroxymethylfurfural and isocarpus glycoside contents in Rehmannia glutinosa charcoal as the response value, a response surface experimental design was performed to further optimize the processing process of Rehmannia glutinosa charcoal, and obtain the optimal processing time and processing temperature. The preferred Rehmannia glutinosa charcoal process of the present invention is safe and effective, and provides a basis for the quality control of Rehmannia glutinosa charcoal. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 In the figure, (a) is the weight loss curve of each raw material with time, (b) is the weight loss curve of each raw material with temperature, (c) is the DTG curve of each raw material with time, and (d) is the DTG curve of each raw material with temperature. In the figure, A is 5-HMF reference, B is reference medicinal material powder, C is verbascoside extract, D is iso-verbascoside reference, E is Rehmannia root medicinal material powder, and F is verbascoside reference.

[0019] Figure 2 In the figure, A is the liquid chromatogram of 5-HMF, and B is the liquid chromatogram of isocarpus glycoside.

[0020] Figure 3In the figure, A is the comprehensive score of 5-HMF content at different times, and B is the comprehensive score of 5-HMF content at different temperatures.

[0021] Figure 4 In the figure, A is the comprehensive score of the isovarbasoside content at different times, and B is the comprehensive score of the isovarbasoside content at different temperatures.

[0022] Figure 5 In the figure, A is a 3D diagram of the interaction of various factors on the carbonized processing technology of Rehmannia glutinosa, and B is a plane diagram. DETAILED DESCRIPTION

[0023] The following is a detailed description of the technical solutions in the embodiments of the present invention, using preferred embodiments and accompanying drawings in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0025] The experimental instruments and materials are shown in Table 1 and Table 2 respectively.

[0026] Table 1 Experimental instruments The Rehmannia root was purchased in Shanxi and later identified by Professor Zhang Shuosheng of the School of Traditional Chinese Medicine and Food Engineering of Shanxi University of Traditional Chinese Medicine as the fresh or dried tuberous root of Rehmannia glutinosa Libosch. of the Scrophulariaceae family.

[0027] Table 2 Experimental materials Example 1 A method for optimizing the processing technology of Rehmannia glutinosa charcoal comprises the following steps: (1) After crushing Rehmannia glutinosa to obtain Rehmannia glutinosa powder, verbascoside, isovalascoside and 5-hydroxymethylfurfural from Rehmannia glutinosa are extracted to obtain verbascoside, isovalascoside and 5-hydroxymethylfurfural extracts.

[0028] Preparation of test solution Take about 1g of crude powder of this product, accurately weigh it, place it in a stoppered conical flask, accurately add 50mL of methanol, weigh the weight, ultrasonically treat (power 200W, frequency 40kHz) for 30 minutes, let cool, weigh it again, make up the lost weight with methanol, shake it well, filter it, accurately measure 5mL of the filtrate, place it in a 10mL volumetric flask, add pure water to dilute to the scale, shake it well, filter it, and take the filtrate to obtain the product.

[0029] Chromatographic conditions The chromatographic column was a Hypersil GOLD aQC18 column (250 mm × 4.6 mm, 5 μm) with acetonitrile-0.1% phosphoric acid solution as the mobile phase for gradient elution; the column temperature was 35°C; the injection volume was 10 μL; and the detection wavelength was 284 nm.

[0030] Table 3 Mobile phase gradient elution program Preparation of Isophora scabrachoside Solution Preparation of reference solution Take about 1g of crude powder of this product, accurately weigh it, place it in a stoppered conical flask, accurately add 50mL of methanol, weigh the weight, ultrasonically treat (power 200W, frequency 40kHz) for 30 minutes, let cool, weigh it again, make up the lost weight with methanol, shake it well, filter it, accurately measure 5mL of the filtrate, place it in a 10mL volumetric flask, add pure water to dilute to the scale, shake it well, filter it, and take the filtrate to obtain the product.

[0031] Chromatographic conditions The chromatographic column was a Hypersil GOLD aQC18 column (250 mm × 4.6 mm, 5 μm), with a volume flow rate of 1 mL / min and a column temperature of 25°C. The mobile phase was acetonitrile-0.1% phosphoric acid aqueous solution (16:84), and the detection wavelength was 334 nm.

[0032] Preparation of 5-hydroxymethylfurfural solution Preparation of reference solution Take an appropriate amount of 5-methylfurfural reference substance, accurately weigh it, and add mobile phase to make a solution containing 10 mg per 1 mL.

[0033] (2) Thermal analysis technology was used to study the pyrolysis characteristics of verbascoside, iso-verascoside and 5-hydroxymethylfurfural extracts. Based on the results of the pyrolysis characteristics study, the processing temperature range and processing time range of Rehmannia glutinosa charcoal were preliminarily obtained.

[0034] Thermal analysis experiments were conducted on different components of Rehmannia glutinosa, and the results are shown in Table 4. The mass fraction of Rehmannia glutinosa raw medicinal powder will change in different temperature ranges. The Rehmannia glutinosa raw medicinal powder undergoes dehydration at room temperature ~ 150 ° C. Verbascoside, isovalercoside and 5-hydroxymethylfurfural are all in the dehydration stage, and the pyrolysis weight loss is between 2.05% and 8.06%; the 183 ° C ~ 376 ° C stage is the main pyrolysis stage of the verbascoside control, and the maximum pyrolysis rate is 9.01% / min at 288.6 ° C, and the mass fraction decreases by 28.22%; the 155 ° C ~ 243 ° C stage is the main pyrolysis stage of the verbascoside extract, and the maximum pyrolysis rate is 7.92% at 207.8 ° C, and the mass fraction is 24.78%; the 150 ° C ~ 284 ° C stage is 5 The maximum pyrolysis stage of -hydroxymethylfurfural was at 208.5℃, with a maximum pyrolysis rate of 7.57% / min and a mass fraction reduction of 22.25%; the maximum pyrolysis stage of 5-hydroxymethylfurfural extract was at 102℃~332℃, with a maximum pyrolysis rate of 14.14% / min at 294.8℃ and a mass fraction reduction of 35.70%; the main pyrolysis stage of the isocarpus glycoside reference was at 198℃~350℃, with a maximum pyrolysis rate of 10.84% / min at 290.6℃ and a mass fraction reduction of 24.11%; the main pyrolysis stage of the isocarpus glycoside extract was at 157℃~290℃, with a maximum pyrolysis rate of 2.06% / min at 294.1℃ and a mass fraction reduction of 51.04%.

[0035] The TG-DTG-Temp curve shows that the isocarpus glycoside component experienced its first weight loss at 220°C and completely lost weight when the temperature reached 450°C; 5-HMF completely lost weight at 320°C; and the Rehmannia glutinosa polysaccharide component completely lost weight at 413°C. The TG-DTG-Time curve also shows that the isocarpus glycoside component completely lost weight in 40 minutes, 5-HMF completely lost weight in 30 minutes, and the polysaccharide component completely lost weight in 38 minutes.

[0036] According to the theory of charcoal-frying, the medicinal effect should be retained while charcoal-frying. It is concluded that the processing temperature should be between 180℃ and 220℃, and the processing time should be between 10min and 20min.

[0037] Table 4 Pyrolysis characteristics of verbascoside, isovalascoside and 5-hydroxymethylfurfural (3) Based on the preliminary obtained processing temperature and processing time ranges of Rehmannia glutinosa charcoal, the contents of 5-hydroxymethylfurfural and isocarpus glycoside in Rehmannia glutinosa charcoal were calculated by high performance liquid chromatography. The contents of 5-hydroxymethylfurfural and isocarpus glycoside were used as evaluation indicators, and the processing temperature and processing time were used as single factor variables. A comprehensive score calculation was performed. According to the comprehensive score calculation results, the optimal processing temperature range and processing time range were further determined.

[0038] Effect of processing temperature on the processing technology of Rehmannia glutinosa charcoal Take 5 portions of Rehmannia glutinosa, 100g each, and divide them into different sizes. Put them into a medicine stir-frying machine and set the temperature to 180℃, 190℃, 200℃, 210℃, and 220℃ for 15min. Take them out and let them cool to obtain Rehmannia glutinosa charcoal slices.

[0039] Effect of processing time on the processing technology of Rehmannia glutinosa charcoal Take 5 portions of Rehmannia glutinosa, 100 g each, and divide them into different sizes. Put them into a medicine frying machine, set the temperature at 200°C, and fry for 10 min, 13 min, 15 min, 17 min, and 20 min. Take them out and let them cool to obtain Rehmannia glutinosa charcoal slices.

[0040] Content determination About 1 g of Rehmannia glutinosa charcoal powder was taken and accurately weighed. The test solution was prepared according to the above method, and 5-hydroxymethylfurfural was determined. The chromatographic peak area of ​​5-hydroxymethylfurfural was recorded. The test solution was prepared using the above method, and isocarpus glycoside was determined. The chromatographic peak area of ​​isocarpus glycoside was recorded, and the contents of 5-hydroxymethylfurfural and isocarpus glycoside were calculated. The results are shown in Table 5 below.

[0041] Table 5 Contents of 5-hydroxymethylfurfural and isocarpus glycoside in Rehmannia glutinosa charcoal at different processing times It can be seen from Table 6 that under the condition of a processing time of 15 min, as the processing temperature increases, the content of 5-hydroxymethylfurfural gradually increases, and the content of isocarpus glycoside also gradually increases.

[0042] Table 6 Contents of 5-hydroxymethylfurfural and isovanoscoside in Rehmannia glutinosa charcoal at different processing temperatures It can be seen from Table 6 that under the condition of a processing temperature of 200°C, with the increase of processing time, the content of 5-hydroxymethylfurfural will gradually increase, and the content of isocarpus glycoside will also gradually increase.

[0043] Content determination results According to the content of the two components in the sample, the comprehensive score is calculated. The results are shown in Figure 1 and Figure 2,Depend on Figure 1 and Figure 2 It can be seen that under the condition of a processing time of 15 minutes, with the increase of processing temperature, the content of 5-hydroxymethylfurfural will gradually increase, and the content of isocarpus glycoside will also gradually increase. Under the condition of a processing temperature of 200℃, with the increase of processing time, the content of 5-hydroxymethylfurfural will gradually increase, and the content of isocarpus glycoside will also gradually increase. Therefore, it is further determined that the optimized processing temperature is 200℃~220℃, and the processing time is 13min~17min.

[0044] (4) With the further determined optimal range of processing temperature and processing time as independent variables and the comprehensive score of 5-hydroxymethylfurfural and isocarpus glycoside content in Rehmannia glutinosa charcoal as the response value, a response surface experimental design was conducted to further optimize the processing technology of Rehmannia glutinosa charcoal and obtain the optimal processing time and processing temperature.

[0045] Optimization of the processing technology of Rehmannia glutinosa charcoal by response surface methodology Based on a single-factor experiment, processing time (A) and processing temperature (B) were selected as variables. Using Design Expert 13 software, the processing process was optimized using response surface analysis, with the combined score (Y) of the 5-hydroxymethylfurfural and isocarpus glycoside contents in Rehmannia glutinosa charcoal as the response value. Ultimately, the optimal processing conditions for Rehmannia glutinosa charcoal were determined, including the factor variables and the response surface methodology experimental design and results. The results are shown in Table 7.

[0046] Table 7 Results of single factor variable and response surface design experiments Analyze the data The data were analyzed using Design Expert 13 software and are shown in Table 8. The corresponding quadratic equation y = 0.8508 + 0.0112*A - 0.0282*B + 0.0054*AB - 0.0125*A was obtained using the 3D model diagram and experimental results. 2 -0.0896*B 2 , where r 2 =0.9335. This model explains 93.35% of the response variation, indicating a good fit and a small experimental error. This model can be used for analysis. Based on the various factors, the influence of 5-hydroxymethylfurfural and isocarpus glycosides in Rehmannia glutinosa charcoal on the content of charcoal is, from greatest to least, in the order of frying temperature > frying time.

[0047] Table 8 Analysis of variance Response surface experiment results Based on this model, a 3D response surface diagram was drawn to show the interaction between frying time and frying temperature on the processing technology of Rehmannia glutinosa charcoal. Figure 3 .Using Design-Export 13 software for optimization, the optimal processing parameters of Rehmannia glutinosa charcoal were processing temperature of 210℃ and processing time of 15min, and its predicted score was 0.65888.

[0048] Process result verification Based on actual practice and the optimal results provided by the software, the optimal process parameters for Rehmannia glutinosa charcoal were adjusted to a processing time of 210°C and a processing temperature of 15 minutes. Three parallel experiments were conducted, and the results showed that the average comprehensive score for 5-hydroxymethylfurfural and isocarpus glycosides was 0.6777, which was very close to the predicted value, demonstrating that the response surface methodology is effective in fitting the processing process.

[0049] Preparation method of Rehmannia glutinosa charcoal According to the Ningxia Chinese medicine preparation specifications, the preparation process of Rehmannia glutinosa charcoal is as follows: steam Rehmannia glutinosa according to the steaming method (Part IV 0213 of the 2020 edition of the "Chinese Pharmacopoeia") until it is black and smooth, take it out and cut into thick slices to dry, or stew it with wine (Part IV 0213 of the 2020 edition of the "Chinese Pharmacopoeia") until the wine is absorbed (30-50k of rice wine is used for every 1000kg of raw Rehmannia glutinosa), cut into thick slices, and dry to obtain Rehmannia glutinosa charcoal. Put the Rehmannia glutinosa slices in a pot, heat over high heat, and stir-fry until bubbles appear, the surface is charred black, and the inside is charred brown. Spray a little water until the water is gone and the sparks are gone, take it out, dry and cool thoroughly, and you will get Rehmannia glutinosa charcoal.

[0050] discuss The present invention determines the content of 5-hydroxymethylfurfural and isocarboside, the main components of Rehmannia glutinosa charcoal, and uses response surface methodology for fitting to obtain the optimal processing conditions. The experimental results show that after frying, the content of 5-hydroxymethylfurfural and isocarboside in Rehmannia glutinosa charcoal gradually increases with the increase of processing temperature and processing time. The optimal processing conditions are a processing temperature of 210°C and a processing time of 15 minutes. Experimental studies have shown that the thermal decomposition of Rehmannia glutinosa at 190°C to 350°C causes them to have a large thermal weight loss. The mass fraction of the C element in raw Rehmannia glutinosa charcoal and cooked Rehmannia glutinosa charcoal is higher than that in raw Rehmannia glutinosa and cooked Rehmannia glutinosa, and the mass fraction of their components such as polysaccharides, alcohols and amino acids is less than that in raw Rehmannia glutinosa and cooked Rehmannia glutinosa. The chemical composition and microstructure of raw Rehmannia glutinosa and cooked Rehmannia glutinosa are similar, and the chemical composition and microstructure of raw Rehmannia glutinosa charcoal and cooked Rehmannia glutinosa charcoal are more similar.

[0051] Research has shown that Rehmannia root significantly strengthens cardiac contractility, especially for weakened hearts. It can also shorten blood clotting time, effectively stopping bleeding. However, careful dosage is crucial when using Rehmannia root as a medicinal herb, as it can be harmful to the body. Furthermore, Rehmannia root has anti-tumor, blood sugar-lowering, hepatitis and diphtheria treatments, and a boost in the body's defenses.

[0052] In summary, different frying temperatures and times will affect the quality of Rehmannia glutinosa. The preferred Rehmannia glutinosa charcoal process of the present invention is stable and effective, which provides a basis for the quality management of Rehmannia glutinosa charcoal and lays an experimental foundation for the formulation and development of quality standards for traditional Chinese medicine slices in my country.

[0053] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0054] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for optimizing the processing technology of Rehmannia glutinosa charcoal, characterized in that: The following steps are involved: After crushing the Rehmannia glutinosa charcoal to obtain Rehmannia glutinosa charcoal powder, extracting verbascoside, isovalascoside and 5-hydroxymethylfurfural from the Rehmannia glutinosa charcoal to obtain verbascoside, isovalascoside and 5-hydroxymethylfurfural extracts; Thermal analysis was used to study the pyrolysis characteristics of verbascoside, isovalascoside and 5-hydroxymethylfurfural extracts. Based on the results of the pyrolysis characteristics study, the processing temperature range and processing time range of Rehmannia glutinosa charcoal were preliminarily obtained. Based on the preliminary obtained processing temperature and processing time ranges of Rehmannia glutinosa charcoal, the contents of 5-hydroxymethylfurfural and isovanoside in Rehmannia glutinosa charcoal were calculated by high performance liquid chromatography. A comprehensive score calculation was performed using the contents of 5-hydroxymethylfurfural and isovanoside as evaluation indicators and processing temperature and processing time as single factor variables. Based on the comprehensive score calculation results, the optimal processing temperature range and processing time range were further determined. With the further determined optimized range of processing temperature and time as independent variables and the comprehensive score of 5-hydroxymethylfurfural and isocarpus glycoside content in Rehmannia glutinosa charcoal as the response value, a response surface experimental design was carried out to further optimize the processing process of Rehmannia glutinosa charcoal and obtain the optimal processing time and temperature.

2. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: When preliminarily determining the processing temperature range and processing time range based on the pyrolysis characteristics results, the weight loss degree of 5-hydroxymethylfurfural and isocarpus glycoside components in Rehmannia glutinosa charcoal was used as the preliminarily optimized processing temperature range and processing time range of Rehmannia glutinosa charcoal.

3. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The pyrolysis characteristics were studied in the range of room temperature to 600℃.

4. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The initial processing temperature of Rehmannia glutinosa charcoal is 180℃~220℃, and the processing time is 10min~20min.

5. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The further optimized processing temperature is 200℃~220℃, and the processing time is 13min~17min.

6. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The optimal processing temperature is 210℃ and the processing time is 15 minutes.

7. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The response surface optimization experiment was conducted using Design Expert 13.0 software according to the central composite design principle, and the quadratic multiple regression equation y = 0.8508 + 0.0112 * A - 0.0282 * B + 0.0054 * AB - 0.0125 * A was obtained. 2 -0.0896*B 2 , where r 2 =0.9335, A represents the processing time, and B represents the processing temperature.

8. The method for optimizing the processing technology of Rehmannia glutinosa charcoal according to claim 1, wherein: The thermal analysis techniques include thermogravimetric analysis and differential thermogravimetric analysis.

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