Method for extracting tea saponin in oil tea cake by desorption-normal pressure internal boiling method

Abstract

The invention relates to the field of medicine and chemical industry, in particular to a method for extracting tea saponin from oil tea cakes through a desorption-normal pressure internal boiling method. According to the method, a desorption-normal pressure internal boiling method is adopted to extract the oil-tea camellia cakes, the method specifically comprises two steps of desorption and extraction, and desorption conditions are as follows: the ethanol concentration is 50-85% (v / v), the ethanol dosage is 15-25mL, and the desorption time is more than 25min; the extraction conditions are as follows: the solid-liquid ratio is (1: 7.5)-(1: 20) g / mL, the extraction time is 6-15 minutes, and the extraction temperature is 85-95 DEG C. According to the method disclosed by the invention, the extraction rate of the tea saponin in the oil-tea cake is relatively high and can reach 15% or above, the operation is simple, a feasible method is provided for improving the extraction rate of the tea saponin in the oil-tea cake, and a certain reference is provided for extraction of the tea saponin and development of subsequent products.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine extraction, specifically a method for extracting tea saponins from camellia oil cake by desorption-normal pressure internal boiling. Background Technology

[0002] Camellia seed cake (also known as tea cake or tea meal) is a residue produced during the extraction of tea oil from camellia seeds. It can be used as a raw material for livestock and poultry feed. Studies have found that the main chemical components of tea meal include sugars, moisture, protein, and saponins, with tea saponins accounting for approximately 10%-15% of the total content. Due to its strong foaming, emulsifying, and wetting properties, as well as its anti-cancer, anti-inflammatory, and antibacterial biological activities, tea saponins have been widely used in the food, pharmaceutical, and pesticide industries. Simultaneously, tea saponins can also serve as a natural, non-toxic feed additive, promoting the growth performance, product quality, and digestive and absorptive functions of livestock and poultry.

[0003] Based on the physicochemical properties of tea saponins, such as their solubility in hot water, aqueous methanol, and aqueous ethanol, traditional methods for extracting tea saponins mainly include water extraction and organic solvent extraction. With advancements in modern extraction technology, subcritical water extraction, ultrasonic and microwave-assisted extraction, continuous multi-stage countercurrent water extraction, aqueous enzymatic methods, and eutectic solvent extraction are gradually being applied. However, regardless of whether it's water extraction, organic solvent extraction, or assisted methods, there are still drawbacks such as high production costs, complex pretreatment, and demanding equipment requirements.

[0004] Internal boiling is a novel method that enhances the extraction process and increases the extraction rate by inducing internal boiling of the desorbent through convective mass transfer. It comprises two steps: desorption and thermal extraction. Specifically, a suitable amount of low-boiling-point desorbent is first added to the extract to desorb for a certain period. Then, a large amount of high-temperature extraction solvent (higher than the boiling point of the desorbent) is rapidly added. Small bubbles are generated on the surface of the extract, allowing most of the effective components to enter the extraction solvent. Studies have shown that internal boiling method is advantageous for extracting tea polyphenols, polysaccharides, saponins, and osmanthus leaf flavonoids due to its low temperature and short extraction time.

[0005] Currently, although there are methods for extracting tea saponins from camellia oil cake by internal boiling, such as patent CN102276679 (a method for extracting high-purity tea saponins from camellia oil cake by vacuum boiling), which uses defatted camellia oil cake as raw material, aqueous ethanol as extraction solvent, and vacuum boiling extraction, the extract is filtered and passed through a ceramic membrane. The ethanol in the tea saponin solution passed through the ceramic membrane is recovered and concentrated. The concentrate is then separated by macroporous resin adsorption and medium-low pressure column chromatography to prepare high-purity camellia oil saponins. However, the process is complex and requires many steps and equipment, which is not conducive to large-scale industrial production.

[0006] Therefore, it is urgent to find a simple, efficient, and suitable method for extracting tea saponins from large quantities of camellia seed cake. Summary of the Invention

[0007] To address the aforementioned technical problems in the existing technology, this invention provides a method for extracting tea saponins from camellia oil cake meal using a desorption-atmospheric pressure internal boiling method, as detailed below:

[0008] A method for extracting tea saponins from camellia oil cake meal using a desorption-atmospheric pressure internal boiling method is disclosed. The method comprises two steps: desorption and extraction. The desorption conditions are: ethanol concentration 50-85% (v / v), ethanol volume 15-25 mL, and desorption time ≥25 min. The extraction conditions are: material-liquid ratio 1:7.5-1:20 g / mL, extraction time 6-15 min, and extraction temperature 85-95℃.

[0009] Furthermore, the ethanol concentration is specifically a volume ratio concentration.

[0010] Furthermore, the specific desorption conditions are: ethanol concentration of 85%, ethanol volume of 25 mL, and desorption time of 30 min.

[0011] Furthermore, the extraction conditions are specifically: a material-to-liquid ratio of 1:10 g / mL, an extraction time of 15 min, and an extraction temperature of 90℃.

[0012] Furthermore, the method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling specifically includes the following steps:

[0013] (1) Desorption: Add an ethanol aqueous solution to the camellia oil cake and pulp for desorption;

[0014] (2) Extraction: Quickly add distilled water with a boiling point higher than that of aqueous ethanol to the desorbed camellia cake, and place it in a constant temperature water bath for extraction; filter the supernatant to obtain camellia cake extract.

[0015] Furthermore, the camellia oil cake meal is dried and defatted camellia oil cake meal. Specifically, it is obtained by drying the camellia oil cake meal at 60°C, pulverizing it, and then defatting the pulverized camellia oil cake meal with n-hexane.

[0016] Furthermore, in step (2) extraction, the tea residue obtained after filtering the supernatant is washed 2-3 times with 80% ethanol, and the washing liquid is transferred and combined with the supernatant.

[0017] Furthermore, in step (2) extraction, the extract is filtered using a 0.45 μm microporous membrane.

[0018] Compared with the prior art, the technical effects of this invention are reflected in:

[0019] This invention employs a desorption-atmospheric pressure internal boiling method to extract tea saponins from camellia oil cake, specifically including two steps: desorption and extraction. Desorption conditions: ethanol concentration 50-85% (v / v), ethanol volume 15-25 mL, desorption time ≥25 min; extraction conditions: material-to-liquid ratio 1:7.5-1:20 g / mL, extraction time 6-15 min, extraction temperature 85-95℃. This method achieves a high extraction rate of tea saponins from camellia oil cake, exceeding 15%, and is simple to operate and process, requiring only one extraction. It does not require complex equipment; a simple water bath is sufficient, making it more suitable for industrial production. Furthermore, it provides a practical method for improving the extraction rate of tea saponins from camellia oil cake, offering a reference for tea saponin extraction and the development of subsequent products. Attached Figure Description

[0020] Figure 1 This is a graph showing the effect of desorbent concentration.

[0021] Figure 2 This is a graph showing the effect of desorbent dosage.

[0022] Figure 3 This is a graph showing the effect of desorption time.

[0023] Figure 4 This is a graph showing the effect of the extractant-to-liquid ratio.

[0024] Figure 5 This is a graph showing the effect of extraction time.

[0025] Figure 6 This is a graph showing the effect of extraction temperature.

[0026] Figure 7 It is a response surface plot and contour plot of the interaction of three factors. Detailed Implementation

[0027] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description.

[0028] Example

[0029] Method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method

[0030] 1. Materials and Methods

[0031] 1.1 Materials and Instruments

[0032] Camellia oil cake was obtained by pressing and extracting oil from camellia seeds after dehulling, and was purchased from Guizhou Runhua Camellia Oil Comprehensive Development Co., Ltd.; tea saponin standard with HPLC content ≥90% was purchased from Sichuan Weikeqi Biotechnology Co., Ltd.; n-hexane and anhydrous ethanol of analytical grade were purchased from Chengdu Jinshan Chemical Reagent Co., Ltd.; methanol of chromatographic grade was purchased from TEDIA Corporation, USA; and water was ultrapure water.

[0033] BSM-220.4 electronic analytical balance (Shanghai Zhuojing Electronic Technology Co., Ltd.); HH type digital display constant temperature water bath (Jiangsu Zhongda Instrument Technology Co., Ltd.); Agilent 1260 Infinity II liquid chromatograph (Agilent Technologies, Inc., USA).

[0034] 1.2 Test Methods

[0035] 1.2.1 Pretreatment of Camellia oleifera cake and extraction of tea saponins by internal boiling method

[0036] Camellia oil cake was dried and pulverized at 60℃. The pulverized camellia oil cake was then defatted with n-hexane. The defatted sample was pulverized, sieved, and stored in a desiccator for later use. 1.00g of the dried and defatted camellia oil cake powder was accurately weighed into an Erlenmeyer flask, and an appropriate amount of ethanol-water solution of a certain concentration (volume fraction) was added. The mixture was allowed to decompose at room temperature for a certain period of time, during which time the ethanol solution would fully penetrate the internal cells of the camellia oil cake.

[0037] Quickly add a certain amount of distilled water with a boiling point higher than that of aqueous ethanol, and place in a constant temperature water bath for a certain period of time for extraction; filter the supernatant into a 100 mL volumetric flask, wash the tea cake residue with 80% ethanol 2-3 times, transfer the washing liquid to a volumetric flask and make up to volume to obtain the tea cake residue extract, filter the extract through a 0.45 μm microporous membrane and use it for liquid chromatography analysis.

[0038] 1.2.2 Method for determining tea saponin content

[0039] 1.2.2.1 Standard Curve Construction

[0040] To prepare a stock solution with a mass concentration of 10.118 mg / mL: Accurately weigh an appropriate amount of tea saponin standard, dissolve it in a small amount of ethanol aqueous solution (80%, v / v) and transfer it to a 50 mL volumetric flask, then dilute to volume and shake well.

[0041] Linearity investigation: Accurately transfer 0.50, 1.00, 2.00, 4.00, 6.00, and 8.00 mL of standard stock solution, dilute with 80% ethanol, and bring the volume to 25 mL in volumetric flasks. Perform liquid chromatography analysis on the six standard solutions under chromatographic conditions. Plot peak area-concentration curves. The regression equation is: y = 3.0990x + 130.7244, with a correlation coefficient R0. 2 The value is 0.9995, indicating a good linear correlation.

[0042] 1.2.2.2 Chromatographic conditions

[0043] HPLC can rapidly determine the content of tea saponins, and adjustments can be made based on actual conditions.

[24] The subsequent chromatographic conditions were as follows: EclipsePlus C18 column (4.6 mm × 150 mm, 5 μm); mobile phase: methanol:water (60:40) with isocratic elution; flow rate: 0.5 mL / min; injection volume: 10 μL; column temperature: 30 ℃; detection wavelength: 265 nm.

[0044] 1.2.2.3 Calculation of tea saponin extraction rate

[0045] The calculation formula is as follows:

[0046]

[0047] In the formula, c: the mass concentration of tea saponins in the tea seed extract after filtration and dilution (g / mL), v: the final volume of the tea seed extract (mL), and m: the mass of the tea seed cake (g).

[0048] 1.2.3 Single-factor experimental design

[0049] 1.2.3.1 Investigate the concentration of the desorbent ethanol

[0050] Accurately weigh 1.00g of tea seed powder into 5 portions in 100 stoppered conical flasks, add 10mL of different concentrations of eluent ethanol (50%, 60%, 70%, 80%, 90%; v / v), and elute at room temperature for 30min. Quickly add hot water with a material-to-liquid ratio of 1:40 (g / mL), place in a constant temperature water bath, maintain the extraction temperature at 80℃, and extract for 10min. Examine the changes in the extraction rate of tea saponins.

[0051] 1.2.3.2 Examining the dosage of desorbent

[0052] Accurately weigh 1.00g of tea seed powder into 5 portions in 100 stoppered conical flasks, and add different volumes of 80% ethanol (5, 10, 15, 20, and 30 mL) of eluent. Elute at room temperature for 30 min. Quickly add hot water at a material-to-liquid ratio of 1:40 (g / mL), place in a constant temperature water bath, maintain the extraction temperature at 80℃, and extract for 10 min. Observe the change in tea saponin extraction rate.

[0053] 1.2.3.3 Examining desorption time

[0054] Accurately weigh 1.00g of tea seed powder into 5 portions and place them into 100 stoppered conical flasks. Add 20mL of 80% ethanol as an eluent and elute at room temperature for 5, 10, 20, 30, and 40 minutes, respectively. Quickly add hot water with a material-to-liquid ratio of 1:40 (g / mL), place the flasks in a constant temperature water bath, maintain the extraction temperature at 80℃, and extract for 10 minutes. Observe the changes in the extraction rate of tea saponins.

[0055] 1.2.3.4 Examine the extractant-to-liquid ratio

[0056] Accurately weigh 1.00g of tea seed powder into 5 portions and place them into 100 stoppered conical flasks. Add 20mL of 80% ethanol as an eluent and elute at room temperature for 30min. Quickly add hot water with different material-to-liquid ratios (1:5, 1:10, 1:20, 1:30, 1:40), place the flasks in a constant temperature water bath, maintain the extraction temperature at 80℃, and extract for 10min. Examine the changes in the extraction rate of tea saponins.

[0057] 1.2.3.5 Examining extraction time

[0058] Accurately weigh 1.00g of tea seed powder into 5 portions in 100 stoppered conical flasks, add 20mL of 80% ethanol as an eluent, and elute at room temperature for 30min. Quickly add hot water with a material-to-liquid ratio of 1:10, place in a constant temperature water bath, maintain the extraction temperature at 80℃, and extract for 6, 8, 10, 15, and 20min respectively to examine the changes in the extraction rate of tea saponins.

[0059] 1.2.3.6 Examine the extraction temperature

[0060] Accurately weigh 5 portions of 1.00g tea seed cake powder into 100-stopper conical flasks, add 20mL of 80% ethanol as an eluent, and elute at room temperature for 30min; quickly add hot water with a material-to-liquid ratio of 1:10, place in a constant temperature water bath, and extract at different temperatures.

[27] The tea saponin extraction rate was examined by soaking the tea at (75, 80, 85, 90, 100℃) for 10 min.

[0061] 1.2.4 PB Experimental Design (see Table 1)

[0062] The main purpose of the Plackett-Burman experimental design was to investigate the factors that had a significant impact on the extraction rate of tea saponins among six single factors. Two levels, high (+1) and low (-1), were selected for the factors with significant effects. The extraction rate of tea saponins was used as the evaluation index. Table 1 shows the results of 12 experimental combinations designed using Design-Expert 8.0.6 software.

[0063] Table 1. Levels of Factors in the Plackett-Burman Experiment

[0064]

[0065] 1.2.5 Box-Behnken response surface methodology (see Table 2)

[0066] Based on the Plackett-Burman experiment, the concentration of the eluent, the amount of eluent, and the extraction time were used as independent variables, and the extraction rate of tea saponin was used as the dependent variable. Table 2 shows the design scheme. Each factor was designed with three levels, and a total of 17 experimental points were designed.

[0067] Table 2 Response Surface Experimental Design Scheme

[0068]

[0069] 1.3 Data Processing

[0070] Data analysis and plotting for single-factor experiments were performed using Excel 2019 and Origin 9.1 software. The design and results analysis of the PB and BBD response surface optimization experiments were performed using Design-Expert 8.0.6 software. All experiments were repeated three times, and the results are expressed as averages.

[0071] 2 Results and Analysis

[0072] 2.1 Single-factor experiment

[0073] 2.1.1 Investigate the concentration of the desorbent ethanol (see...) Figure 1 )

[0074] Figure 1 The effect of different concentrations of ethanol as an eluent on the extraction rate of tea saponins was investigated with the following parameters: 10 mL ethanol as the eluent, 30 min eluent time, 1:40 extractant-to-liquid ratio, 10 min extraction time, and 80℃ extraction temperature. Analysis showed that the extraction rate increased continuously within the eluent concentration range of 50%-90%, but decreased after exceeding 80%. According to the principle of "like dissolves like," when the ethanol concentration is 60%–80%, the ethanol solution can fully penetrate the plant cell wall and maximize the desorption of the active ingredients. Too low an ethanol concentration results in low solubility of tea saponins, insufficient desorption, and a low extraction rate; too high an ethanol concentration reduces the concentration difference between the internal and external solutions of the tea meal, thus decreasing the boiling point difference and resulting in less vigorous boiling. Therefore, 80% ethanol was selected as the optimal eluent concentration.

[0075] 2.1.2 Examine the dosage of desorbent (see...) Figure 2 )

[0076] Figure 2The effects of different amounts of eluent on the extraction rate of tea saponins were investigated under the following conditions: ethanol concentration of 80% eluent, eluent time of 30 min, extractant-to-liquid ratio of 1:40, extraction time of 10 min, and extraction temperature of 80℃. Analysis showed that when the eluent dosage was 20 mL, the ethanol solution could completely penetrate the interior of the camellia oil cake, resulting in the highest extraction rate. Therefore, 20 mL was selected as the optimal eluent dosage.

[0077] 2.1.3 Examining desorption time (see...) Figure 3 )

[0078] Figure 3 The effects of different desorption times on the extraction rate of tea saponins were investigated under the following conditions: ethanol concentration of 80%, desorption agent volume of 20 mL, extractant-to-liquid ratio of 1:40, extraction time of 10 min, and extraction temperature of 80℃. Analysis showed that the extraction rate of tea saponins increased with increasing desorption time, reaching its maximum at 30 min. Afterward, the extraction rate tended to plateau with further increases in desorption time. This may be because a short desorption time would prevent sufficient contact between the ethanol solution and the tea oil cake powder. As the desorption time increased, the ethanol penetrated more fully, leading to more complete desorption and a continuous increase in the extraction rate of tea saponins until saturation was reached. Therefore, 30 min was selected as the optimal desorption time.

[0079] 2.1.4 Investigate the extractant-to-liquid ratio (see...) Figure 4 )

[0080] Figure 4 The effects of different extractant-to-liquid ratios on the extraction rate of tea saponins were investigated under the following conditions: ethanol concentration of the extractant (80%), extractant volume (20 mL), extractant time (30 min), extraction time (10 min), and extraction temperature (80℃). Analysis showed that the extraction rate of tea saponins reached its maximum at an extractant-to-liquid ratio of 1:10. With further increases in extractant volume, the extraction rate initially decreased and then leveled off. Therefore, 1:10 was selected as the optimal extractant-to-liquid ratio.

[0081] 2.1.5 Examine extraction time (see) Figure 5 )

[0082] Figure 5 The effects of different extraction times on the extraction rate of tea saponins were investigated under the following conditions: ethanol concentration of 80% eluent, eluent volume of 20 mL, eluent time of 30 min, extractant-to-liquid ratio of 1:10, and extraction temperature of 80℃. Analysis showed that when the extraction time was less than 10 min, the extraction rate of tea saponins increased with increasing extraction time; however, when the extraction time was greater than 10 min, the extraction rate decreased slightly. Considering practical operation, 10 min was selected as the optimal extraction time.

[0083] 2.1.6 Examine extraction temperature (see...) Figure 6 )

[0084] Figure 6 The effects of different extraction temperatures (75–100 °C) on the extraction rate of tea saponins were investigated with the following parameters: ethanol concentration of the eluent (80%), eluent volume (20 mL), eluent time (30 min), extractant-to-liquid ratio (1:10), and extraction time (10 min). Analysis showed that the extraction rate initially increased and then decreased with increasing temperature, reaching its highest value at 90 °C. This is likely because the structure of the active ingredient is destroyed in a high-temperature environment. Therefore, 90 °C was selected as the optimal extraction temperature.

[0085] 2.2 Screening of significant factors affecting tea saponin extraction rate (see Tables 3 and 4)

[0086] As described in section 1.2.4, the PB experimental design employed two levels of high (+) and low (-) for six single-factor factors: desorbent concentration (A), eluent dosage (B), eluent time (C), extractant-to-liquid ratio (D), extraction time (E), and extraction temperature (F). Table 3 shows the response values ​​of 12 randomized experiments completed using Design-Expert 8.0.6 software.

[0087] The results of the ANOVA in Table 4 show that the model significance test (P = 0.0128) indicates that the regression model has a significant impact on the extraction rate of tea saponin within the selected level range. Analysis of the P-values ​​shows that the P-values ​​for items A, B, and E are all less than 0.05, indicating they are the three main factors affecting the extraction rate of tea saponin. For items C, D, and F, considering their lack of significant impact on the extraction rate, the optimal results for the single-factor experiments were directly adopted for these three items.

[0088] Table 3 Results of the PB Experimental Design

[0089]

[0090] Table 4. Significance analysis of the PB test

[0091]

[0092]

[0093] Note: Significance is expressed as P-value (**: P < 0.01); (*: P < 0.05), the same applies to the table below.

[0094] 2.3 Response Surface Analysis Results

[0095] 2.3.1 Response surface methodology and results (see Table 5)

[0096] Based on the combined results of single-factor and PB experiments, the extraction rate (%) of tea saponin was used as the evaluation index. The effects of three different levels of three significant factors—desorbent concentration (A, %), desorbent dosage (B, mL), and extraction time (C, min)—on the extraction rate of tea saponin were designed.

[0097] Table 5 Box-Behnken Experimental Design and Results

[0098]

[0099]

[0100] 2.3.2 Analysis of variance for the Box-Behnken experiment (see Table 6)

[0101] Using Design-Expert 8.0.6 software, a multiple regression equation was fitted to the experimental data in Table 5, and an analysis of variance was performed. The resulting regression equation is as follows:

[0102] Y=13.32+0.56A-0.16B+0.36C+0.48AB-0.087AC+0.83BC+0.32A 2

[0103] +0.11B 2 -0.55C 2

[0104] Analysis of Table 6 shows that both the F-value and P-value (P < 0.0001) indicate that the established model is statistically significant. The degree of difference between the model and the experiment can be represented by the lack-of-fit term. In the table, the P-value of the lack-of-fit term is 0.8901 > 0.05, which is not significant and is favorable to the model, indicating that the regression equation can replace the experimental true points for analyzing the experimental results. Among the three significant factors, the concentration of the desorbent has the most significant effect on the extraction rate of tea saponin, followed by the extraction time, and the amount of desorbent is the least significant. In the interaction term, the effects between the desorbent concentration A and the desorbent amount B, and between the desorbent amount B and the extraction time C are extremely significant. In the quadratic term, A... 2 C 2 The impact is extremely significant.

[0105] Table 6. Analysis of Variance for the Box-Behnken Experimental Model

[0106]

[0107]

[0108] 2.3.3 Box-Behnken analysis of optimal extraction parameters (see...) Figure 7 )

[0109] Depend on Figure 7The 3D response surface plot and contour plot show that the slope of the response surface is steep for both desorbent concentration A and extraction time C, indicating that both have a highly significant impact on the response value. With a constant desorbent concentration A, the response value increases with increasing desorbent dosage B, indicating that the interaction of factors A and B significantly affects the extraction rate. With a constant desorbent dosage B, the response value changes steeply with increasing extraction time C, and the contour lines are dense, indicating that the interaction of factors B and C significantly affects the extraction rate. With a constant extraction time C, the response value changes more gradually with increasing desorbent concentration A, and the contour lines are sparse, indicating that the interaction of factors A and C has no significant impact on the extraction rate.

[0110] Further analysis using Design-Expert 8.0.6 software revealed the optimal extraction parameters for the three significant factors to be: desorbent concentration 85%, desorbent volume 25 mL, and extraction time 15 min. Under these conditions, the theoretical extraction rate of tea saponin could reach 15.19%.

[0111] 2.3.4 Model Validation

[0112] 1.00 g of tea seed cake powder was accurately weighed and divided into four parallel samples. Based on the results of single-factor and BBD experiments, tea saponins were extracted using the internal boiling method under the optimal conditions of six factors. The calculated average extraction rate of tea saponins was 15.11%, while the model predicted an extraction rate of 15.19%. The relative error between the two was -0.53%, which is close to the model equation.

[0113] 3. Conclusion

[0114] Tea saponin, as an effective component in camellia oil cake by-products, requires specific extraction methods for comprehensive utilization and to avoid resource waste. However, literature on the internal boiling method for tea saponin extraction is scarce. This experiment used a single-factor pre-combined PB experimental design to screen three factors significantly affecting the extraction rate of tea saponin. Response surface methodology analysis determined the optimal desorption conditions for internal boiling extraction of tea saponin: 85% ethanol concentration (v / v), 25 mL ethanol volume, and 30 min desorption time; and the optimal extraction conditions: a solid-liquid ratio of 1:10 (g / mL), an extraction time of 15 min, and an extraction temperature of 90℃. Under these conditions, the actual extraction rate of tea saponin was 15.11%, indicating the reliability of the established model. The internal boiling method provides a practical approach to improving the extraction rate of tea saponin from camellia oil cake, offering a reference for the extraction of tea saponin and the development of subsequent products.

[0115] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

Claims

1. A method for extracting tea saponins from camellia oil cake residue using a desorption-atmospheric pressure internal boiling method, characterized in that, The desorption-atmospheric pressure internal boiling method was used to extract camellia oil cake and meal, which includes two steps: desorption and extraction. The desorption conditions were: ethanol concentration 50-85% (v / v), ethanol volume 15-25mL, and desorption time ≥25min. The extraction conditions were: material-liquid ratio 1:7.5-1:20g / mL, extraction time 6-15min, and extraction temperature 85-95℃.

2. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 1, characterized in that, The ethanol concentration is specifically a volume ratio concentration.

3. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 1, characterized in that, The specific desorption conditions are: ethanol concentration 85%, ethanol volume 25 mL, and desorption time 30 min.

4. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 1, characterized in that, The specific extraction conditions are: a material-to-liquid ratio of 1:10 g / mL, an extraction time of 15 min, and an extraction temperature of 90℃.

5. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 1, characterized in that, Specifically, the steps include the following: (1) Desorption: Add an ethanol aqueous solution to the camellia oil cake and pulp for desorption; (2) Extraction: Quickly add distilled water with a boiling point higher than that of aqueous ethanol to the desorbed camellia cake, and place it in a constant temperature water bath for extraction; filter the supernatant to obtain camellia cake extract.

6. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 5, characterized in that, The camellia oil cake meal mentioned is dried and defatted camellia oil cake meal.

7. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 6, characterized in that, The dried and defatted camellia oil cake is obtained by drying the camellia oil cake at 60°C, pulverizing it, and then defatting the pulverized camellia oil cake with n-hexane.

8. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 5, characterized in that, In step (2) extraction, the tea residue obtained after filtering the supernatant is washed 2-3 times with 80% ethanol, and the washing liquid is transferred and combined with the supernatant.

9. The method for extracting tea saponins from camellia seed cake by desorption-atmospheric pressure internal boiling method according to claim 5, characterized in that, In step (2), the extract is filtered through a 0.45 μm microporous membrane.

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