Process for optimally extracting polyphenol-flavone compound from quince seeds by response surface method

Abstract

The invention belongs to the technical field of plant extraction, and particularly relates to a process for optimally extracting a polyphenol-flavone compound from quince seeds through a response surface method. According to the extraction method disclosed by the invention, the quince seeds are subjected to proper treatment, alcohol extraction and ultrasonic treatment, so that total flavonoids and total phenolic acids can be extracted at the same time, the extraction cost is effectively saved, the extraction process is simplified, the extraction efficiency is improved, and the production process is non-toxic, green and environment-friendly.

Description

Technical Field

[0001] The present application belongs to the field of plant extraction technology, and specifically relates to a process for optimizing the extraction of polyphenol-flavonoid complexes from quince using a response surface methodology. Background Art

[0002] The southern Xinjiang region of China boasts abundant quince resources, but utilization is extremely low, with quince seeds, in particular, largely discarded. Currently, there is a lack of research on the chemical composition and bioactivity of quince. Quince, a commonly used medicinal herb in Uyghur medicine, belongs to the genus Cydouia in the Rosaceae family. The seeds of the plant Cydouia oblonga Mill are mostly brown-black in color. Pharmacologically, quince contain a high mucilage content, which, when combined with other medicinal applications, can reduce irritation and delay absorption. Furthermore, literature reports indicate that quince contains a variety of bioactive components, including phenolic acids, flavonoids, organic acids, fatty acids, sterols, and carbohydrates. Phenolic acids and flavonoids, as its primary components, exhibit a wide range of bioactivities, including antioxidant, antiviral, antitumor, antibacterial, anti-inflammatory, anticancer, lipid-lowering, and anti-cardiovascular effects.

[0003] Existing literature on quince extraction processes primarily focuses on flavonoids and triterpenes. Traditionally, the reflux method has been used to extract total flavonoids, a process that is time-consuming, complex, and expensive. Furthermore, total phenolic acids are susceptible to decomposition at high temperatures, making this method unsuitable. Furthermore, both flavonoids and triterpenes require separate extraction, resulting in high costs and low production efficiency.

[0004] Therefore, it is necessary to explore a method for simultaneously extracting total flavonoids and total phenolic acids from quince. Summary of the Invention

[0005] The purpose of this application is to provide a process for optimizing the extraction of polyphenol-flavonoid complexes from quince using a response surface methodology, so as to solve the technical problems of traditional extraction methods such as the use of large amounts of organic solvents, low extraction rates, low selectivity, and long extraction times.

[0006] On the one hand, the present application provides a process for optimizing the extraction of polyphenol-flavonoid complexes from quince using a response surface methodology, comprising:

[0007] (1) Grinding the dried quince to obtain quince powder;

[0008] (2) Adding gradient concentrations of ethanol at different material-liquid ratios, ultrasonically extracting for different times at the same temperature to obtain quince complex extracts;

[0009] (3) Using the response surface design method, the three factors of solid-liquid ratio, ethanol concentration and extraction time were selected as response variables. The optimal point of the single-factor experiment was taken as the center, and one level value above and below the optimal point was taken as the level of the response surface, which was coded as -1, 0, and 1 respectively;

[0010] Taking the extraction rates of total flavonoids and total phenolic acids as response values, polynomial fitting regression was performed on each factor to obtain the regression equation:

[0011] Y1=5.27+0.0754*A-0.4590*B+0.1593*C+0.1454*AB+0.4754*AC+0.1810*BC-0.4077*A2-0.3417*B2-0.2869*C2;

[0012] Y2=12.37+0.7448*A+0.2547*B-0.130*C+0.0521*AB+0.4275*AC-0.1825*BC-0.7438*A2-0.5588*B2-0.6983*C2;

[0013] Wherein, A is the ethanol concentration, B is the solid-liquid ratio, C is the extraction time, Y1 is the total phenolic acid extraction yield, and Y2 is the total flavonoid extraction yield; and

[0014] The regression equation is calculated to obtain the extraction process of the quince complex.

[0015] In one embodiment, in step (3), the material-liquid ratio is 1 g:10 mL, 1 g:20 mL, 1 g:30 mL and 1 g:40 mL.

[0016] In one embodiment, the concentration of ethanol is 0 v / v%, 50 v / v%, 60 v / v%, 70 v / v%, 80 v / v% and 90 v / v%.

[0017] In one embodiment, the range of the response variable is: ethanol concentration is 60 v / v%-80 v / v%; solid-liquid ratio is 20mL-40mL; extraction time is 5min-15min.

[0018] In one embodiment, the method of collecting the extract comprises centrifugation.

[0019] In one embodiment, the centrifugal parameters include: a rotation speed of 3500 r / min-4500 r / min, and a time of 5 min-10 min.

[0020] In one embodiment, the ultrasonic treatment frequency is 38 kHz-42 kHz and the power is 280W-320W.

[0021] In one embodiment, the ultrasonic treatment frequency is 40 kHz and the power is 300W.

[0022] In one embodiment, the extraction process conditions for obtaining the quince complex include: an ethanol concentration of 73.82 v / v%, a solid-liquid ratio of 1:27.98, and an extraction time of 11.36 min.

[0023] In one embodiment, the pulverizing process includes pulverizing using a pulverizer.

[0024] The process method of the present application can simultaneously extract total flavonoids and total phenolic acids by appropriately treating quince, extracting with alcohol, and then ultrasonically treating the quince, effectively saving extraction costs, simplifying the extraction process, and improving extraction efficiency. In addition, the production process is non-toxic and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more fully understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0026] Figure 1 The effects of each single factor on the total phenolic acid and total flavonoid contents in an embodiment of the present application;

[0027] Figure 2 This is the effect of the interaction of various factors on total phenolic acids in an embodiment of the present application;

[0028] Figure 3 This is the effect of the interaction of various factors on total flavonoids in one embodiment of the present application. DETAILED DESCRIPTION

[0029] Below in conjunction with embodiment and example, the application is described in further detail.Should be understood that these embodiment and example are only used to illustrate the application and are not used to limit the scope of the application, and the purpose of providing these embodiment and example is to make the understanding of the disclosure of the application more thorough and comprehensive.It should also be understood that the application can be implemented in many different forms, is not limited to the embodiment and example described herein, and those skilled in the art can make various changes or modifications without violating the connotation of the application, and the equivalent form obtained also falls within the protection scope of the application.In addition, in the description hereinafter, a large amount of specific details are given in order to provide a more complete understanding of the application, and it should be understood that the application can be implemented without one or more of these details.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0031] the term

[0032] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0033] The terms "and / or", "or / and", and "and / or" used herein include any one of two or more related listed items, and also include any and all combinations of the related listed items, wherein the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical and" and also undoubtedly includes technical solutions connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution of all being connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the four-item combination of A, B, C, and D (that is, the technical solution of all being connected by "logical AND").

[0034] In this application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0035] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0036] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc. shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0037] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0038] In this application, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is independent unless otherwise specified and there are no contradictions or constraints.

[0039] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0040] In this application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional values ​​within the numerical interval is considered continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum and maximum values), as well as every numerical value between these two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two numerical endpoints of the numerical range, as well as every integer between the two numerical endpoints. In this document, this is equivalent to directly listing each integer. For example, "t is an integer selected from 1 to 10" means that t is any integer selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. In addition, when multiple ranges are provided to describe a feature or characteristic, these ranges may be combined. In other words, unless otherwise specified, ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0041] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0042] In this application, % (w / w) and wt% both refer to weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0043] All documents mentioned in this application are cited as references in this application, just as each document is cited as a reference individually. Unless they conflict with the invention purpose and / or technical solution of this application, the cited documents involved in this application are cited in their entirety and for all purposes. When cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When cited documents are involved in this application, the examples and preferred embodiments of the cited relevant technical features may also be incorporated into this application as references, but are limited to the ability to implement this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be adaptively amended according to the description in this application.

[0044] The term "quince" refers to Cydonia oblonga Mill., a shrub of the genus Quince in the Rosaceae family. Quince has slender, cylindrical branchlets and ovate, purple-brown, tomentose buds in winter. Leaves are simple, alternate, ovate or oblong, with a rounded or nearly cordate base. They are glabrous above or sparsely pubescent when young and densely villous below, with entire margins. Flowers are solitary, with white, obovate petals and densely tomentose pedicels. Bracts are membranous, ovate, and caducous early. Fruit is pear-shaped, yellow, and fragrant, with persistent, reflexed sepals. The fruit stalk is short and thick. Flowering occurs in April and May, and fruiting occurs in October.

[0045] The term "total flavonoids" refers to a class of natural compounds found widely in plants, exhibiting a variety of biological and pharmacological activities. They are a general term for flavonoids, which typically exist in plants as glycosides or aglycones. The basic structure of flavonoids is a benzo-α-pyrone, consisting of two benzene rings (A and B) connected by a three-carbon chain (C6-C3-C6 structure).

[0046] The term "total phenolic acids" refers to a class of natural compounds widely found in plants, primarily including various phenolic compounds such as caffeic acid, ferulic acid, gallic acid, and chlorogenic acid. The basic structure of phenolic acid compounds is a compound with a carboxyl group (-COOH) attached to a benzene ring.

[0047] The present application provides a process for simultaneously extracting total phenolic acids and total flavonoids from quince, comprising:

[0048] (1) Grinding the dried quince to obtain quince powder;

[0049] (2) Weigh 1 g of quince powder and add different concentrations of ethanol at different material-liquid ratios. Ultrasonic extraction is performed at the same temperature for different times to obtain a solution containing a quince composite extract.

[0050] (3) The response surface design method was used. The three factors of solid-liquid ratio, ethanol concentration and extraction time were selected as response variables. The optimal point of the single-factor experiment was taken as the center. One level value was taken above and below the optimal point as the level of the response surface, and coded as -1, 0, and 1 respectively. The total flavonoids and total phenolic acid extraction rates were used as response values. Polynomial fitting regression was performed on each factor to obtain the regression equation:

[0051] Y1=5.27+0.0754*A-0.4590*B+0.1593*C+0.1454*AB+0.4754*AC+0.1810*BC-0.4077*A2-0.3417*B2-0.2869*C2.

[0052] Y2=12.37+0.7448*A+0.2547*B-0.130*C+0.0521*AB+0.4275*AC-0.1825*BC-0.7438*A2-0.5588*B2-0.6983*C2.

[0053] Wherein, A is ethanol concentration, B is solid-liquid ratio, C is extraction time, Y1 is total phenolic acid extraction yield, and Y2 is total flavonoid extraction yield. The above regression equation was calculated to obtain the optimal extraction process conditions for quince composite extract.

[0054] The mixed solution was subjected to ultrasonic extraction (ultrasonic parameters: frequency: 40 kHz, power: 300 W), and the extract was collected for determination of total phenolic acid and total flavonoid contents.

[0055] In the present application, in step (3), the range of the response variable is: solid-liquid ratio is 1 g: 20-40 mL; ethanol concentration is 60 v / v%-80 v / v%; and extraction time is 10 min-20 min.

[0056] In this application, the optimal extraction process obtained by response surface design was as follows: ethanol concentration 73.82 v / v%, solid-liquid ratio 1:27.98, and extraction time 11.36 min.

[0057] In this application, the single-factor experimental steps are as follows:

[0058] (1) Effect of ethanol concentration on composite extracts: The solid-liquid ratio was set to 1:20, the extraction time was set to 30 min, and ultrasonic extraction was performed using ethanol concentrations of 0 v / v%, 50 v / v%, 60 v / v%, 70 v / v%, 80 v / v%, and 90 v / v% at room temperature.

[0059] (2) Effect of material-liquid ratio on composite extracts: Under the conditions of ethanol concentration of 70%, extraction time of 30 min, and room temperature, ultrasonic extraction was performed using material-liquid ratios of 1 g:10 mL, 1 g:20 mL, 1 g:30 mL, and 1 g:40 mL.

[0060] (3) Effect of extraction time on the composite extract: Under the conditions of ethanol concentration of 70v / v%, solid-liquid ratio of 1g:30mL and room temperature, ultrasonic extraction was performed for 10 min, 15 min, 30 min, 45 min and 60 min respectively.

[0061] In this application, the response surface experiment steps are as follows:

[0062] Based on a single-factor experiment, Design Expert software was used to analyze the relationship between the total phenolic acid and total flavonoid yields in quince extract and the material-to-liquid ratio (A), ethanol concentration (B), and extraction time (C). A three-factor, three-level response surface analysis scheme was designed. This experimental design included a total of 17 experimental points, including five replicates to assess experimental error. The response surface experimental design table is shown in Table 1 below:

[0063] Table 1 Box-Behnken experimental scheme and results

[0064]

[0065] In this application, the standard curve was prepared as follows:

[0066] (1) Preparation of gallic acid standard series concentrations: Accurately weigh 17 mg of gallic acid reference substance and place it in a 25 mL brown volumetric flask. Add anhydrous ethanol to the mark to prepare a gallic acid standard stock solution with a concentration of 0.6222 mg / mL. Accurately pipette 0.5, 1.0 mL, 2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL, and 6.0 mL of the gallic acid standard stock solution into a 25 mL brown volumetric flask, add deionized water to the mark, and shake well. The obtained gallic acid standard series concentrations are 12.44 μg / mL, 24.89 μg / mL, 49.78 μg / mL, 74.66 μg / mL, 99.55 μg / mL, 124.44 μg / mL, and 149.33 μg / mL, and prepare them immediately before use. 1.00 mL of the gallic acid standard series concentration was respectively pipetted into a 25 mL brown volumetric flask, 5.00 mL of deionized water and 1.00 mL of 1.0 mol / L Folin-Phenol reagent were added, shaken, and allowed to stand for 5 min. Then 4.00 mL of 12% sodium carbonate solution was added to each flask, the mixture was diluted to the scale with deionized water, shaken, and allowed to stand at room temperature for 60 min. Using the reagent blank as a reference, an intermediate point was taken to scan at a wavelength of 400 nm to 800 nm. The maximum absorption was found at a wavelength of 760 nm. Therefore, the wavelength selected for the total phenolic acid determination was 760 nm. A standard curve was drawn with the concentration x (μg / mL) as the horizontal axis and the absorbance value A as the vertical axis.

[0067] (2) Preparation of rutin standard solution: Accurately weigh 7.03 mg of rutin reference substance and place it in a 25 mL volumetric flask. Dose the solution to the mark with pure water to prepare a rutin standard stock solution with a concentration of 0.2593 mg / mL. Accurately pipette 0 mL, 0.5 mL, 1.0 mL, 2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL, and 6.0 mL of the rutin standard stock solution into a 25 mL volumetric flask, add 1.0 mL of 5% sodium nitrite solution, shake well, and let it stand for 6 minutes. Then, add 1.0 mL of 10% aluminum nitrate solution and shake well. After 6 minutes, add 10 mL of 4% sodium hydroxide solution and shake well. Dose the solution to the mark with pure water and let it stand for 15 minutes. Using the reagent blank as a reference, scan at an intermediate point at a wavelength of 400 nm to 800 nm. The maximum absorption is at a wavelength of 511 nm. Therefore, the wavelength selected for the total flavonoid determination is 511 nm. Draw a standard curve with absorbance A as the ordinate and concentration (mg / mL) as the abscissa.

[0068] The yield of the complex in this application is calculated as follows:

[0069] Total phenolic acid content (mg / g) = (C1*V1*N) / (m*1000), total flavonoid content (mg / g) = (C2*V2*V 显 ) / (V 吸 *m), where: C1 is the concentration of total phenolic acids in the sample solution (μg / mL); V1 is the constant volume of the sample solution (mL); C2 is the concentration of total flavonoids in the sample solution (mg / mL); V2 is the constant volume of the sample solution (mL), V 显 is the color volume, V 吸 is the volume of the sample liquid; m is the sampling amount of the sample (g); N is the dilution multiple.

[0070] The technical solutions provided in this application are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of this application.

[0071] Example 1

[0072] 1. Experimental Medicinal Materials

[0073] 1. Quince, purchased from Xinjiang Xinlvbao Pharmaceutical Co., Ltd. in November 2024, product batch number: WPZ-YP-241113, production date November 13, 2024.

[0074] 2. Experimental reagents

[0075] Rutin standard and gallic acid standard were purchased from China Food and Drug Inspection Institute, Folin phenol reagent, anhydrous ethanol, anhydrous sodium carbonate, NaOH, NaNO2, Al(NO3)3.

[0076] 3. Instruments and equipment

[0077] DFY-500 grinder, Evolution One UV spectrophotometer, AS2310193 ultrasonic cleaner, analytical balance, LC-LX-L40B desktop low-speed centrifuge, and ultrapure water machine.

[0078] 2. Experimental steps

[0079] Extraction process of the complex:

[0080] Weigh 1g of ground quince powder, add different concentrations of ethanol at different material-liquid ratios, and

[0081] The quince complex extract was obtained by extracting at different temperatures and for different times.

[0082] Effect of ethanol concentration on the extraction rate of the complex:

[0083] The solid-liquid ratio was set to 1:30, the extraction time was set to 30 min, and the extraction was performed using 0%, 50%, 60%, 70%, 80%, and 90% ethanol at room temperature. Figure 1 As shown in Figure a, the total phenolic acid and total flavonoid contents increase with increasing ethanol concentration. The total flavonoid content reaches its maximum at 70%, while the total phenolic acid content reaches its maximum at 80%, followed by a downward trend. Due to the high total flavonoid content, 70% ethanol was selected as the center of the response surface as a priority. Increasing ethanol concentration leads to a decrease in the extraction yield of the complex. This may be because high ethanol concentrations increase the content of fat-soluble substances, resulting in a decrease in the solubility of the complex, which in turn affects the extraction efficiency of the complex.

[0084] Effect of solid-liquid ratio on the extraction rate of the complex:

[0085] The ethanol concentration was set to 70%, the extraction time was 30 min, and the extraction was carried out at room temperature using a solid-liquid ratio of 1:10, 1:20, 1:30, and 1:40. Figure 1 As can be seen from b, under different solid-liquid ratio conditions, with the increase of solid-liquid ratio, total phenolic acids and total flavonoids increased slightly. When the solid-liquid ratio was 30 times, the change was gentle and there was no upward trend. When the dissolution reached equilibrium, increasing the amount of extractant no longer helped the extraction of the complex, so 1:30 was the center point of the response surface.

[0086] Effect of extraction time on the extraction rate of the complex:

[0087] The extraction was carried out at room temperature under the conditions of ethanol concentration of 70%, solid-liquid ratio of 1:30 and 10 min, 15 min, 30 min, 45 min and 60 min respectively. Figure 1 Figure c shows that the longer the ultrasonic time, the less conducive it is to the extraction of total phenolic acids and total flavonoids. Since the phenolic acids and flavonoids in the extract are oxidized and degraded when the ultrasonic time is too long, resulting in a reduction in the extraction amount, 10 min was selected as the center point of the response surface.

[0088] 3. Result Analysis

[0089] Using Design-Expert 13.0 software, we conducted an in-depth analysis of the data in Table 1 and obtained the results shown in Table 2. The data in Table 2 show that extraction time (P < 0.0001) has a highly significant effect on total phenolic acids, while both ethanol concentration and extraction time (P < 0.0001) have a highly significant effect on total flavonoid extraction. To improve the extraction method of quince complexes, regression analysis was performed, resulting in the following regression formula for the effect of various experimental variables on the yield of quince complexes:

[0090] Y1=5.27+0.0754*A-0.4590*B+0.1593*C+0.1454*AB+0.4754*AC+0.1810*BC-0.4077*A2-0.3417*B2-0.2869*C2.

[0091] Y2=12.37+0.7448*A+0.2547*B-0.130*C+0.0521*AB+0.4275*AC-0.1825*BC-0.7438*A2-0.5588*B2-0.6983*C2.

[0092] The results of the variance analysis showed that the model was highly significant (P < 0.01), and the lack-of-fit term was P > 0.05, indicating a good fit. Furthermore, the linear term B and the quadratic terms A2 and B2 all had highly significant effects on the response values ​​Y1 and Y2. Analysis of the model revealed that the order of influence of the three factors on the total phenolic acid content of quince was B > A > C, and the order of influence on the total flavonoid content of quince was A > B > C (see Table 2 for F values).

[0093] Table 2: Results of variance analysis of response surface regression model

[0094]

[0095] Note: P<0.05 indicates a significant effect, and P<0.01 indicates an extremely significant effect.

[0096] Response surface interaction analysis:

[0097] In the process of extracting the complex, the interaction between two factors is crucial because it directly affects the extraction effect. The shape of the surface and contour lines can show the significance of the interaction between the two factors. The more curved the surface and the flatter the contour lines, the more significant the interaction between the two factors. Figure 2 a- Figure 2 As shown in f, it can be seen that the slope of the AC surface is greater than that of AB and BC, and the contour lines are nearly elliptical, which indicates that the interaction between ethanol concentration A and extraction time C has a significant effect on the extraction amount of total phenolic acids in quince, which is consistent with the Y1 result in the P value of variance analysis in Table 2. Figure 3 a- Figure 3 The e-surface degree in the figure shows that the interaction of the three factors has a greater impact on total flavonoids than total phenolic acids. Figure 3 b- Figure 3 As can be seen from the figure f, the effect of AC on total flavonoids is stronger than the interaction between BC and AB, which is consistent with the Y2 result in the P value of the variance analysis in Table 2. By deeply understanding these interactions, the extraction conditions can be optimized more accurately, thereby improving the extraction efficiency of quince complex.

[0098] Example 2

[0099] Experiments were conducted based on the optimal conditions derived from this experimental model. As shown in Table 3, under the theoretically optimal conditions, the theoretical extraction yield of the quince fruit complex was 5.27 mg / g for total phenolic acids and 12.37 mg / g for total flavonoids. Based on practical feasibility, the optimal extraction conditions were adjusted and three parallel validation experiments were conducted. The average total flavonoid content was 12.28 mg / g, close to the predicted value of 12.37 mg / g, and the total phenolic acid content was 5.23 mg / g, close to the predicted value of 5.27 mg / g. The relative errors were both less than 1%, demonstrating the reliability of the optimized technical parameters.

[0100] Table 3 Optimal process

[0101]

[0102] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the scope of protection of the present application. It should also be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent application of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology, characterized in that: include: (1) Grinding the dried quince to obtain quince powder; (2) Adding gradient concentrations of ethanol at different material-liquid ratios, ultrasonically extracting for different times at the same temperature to obtain quince complex extracts; (3) Using the response surface design method, the three factors of solid-liquid ratio, ethanol volume fraction and extraction time were selected as response variables. The optimal point of the single-factor experiment was taken as the center, and one level value above and below the optimal point was taken as the level of the response surface, which was coded as -1, 0, and 1 respectively; Taking the extraction rates of total flavonoids and total phenolic acids as response values, polynomial fitting regression was performed on each factor to obtain the regression equation: Y1=5.27+0.0754*A-0.4590*B+0.1593*C+0.1454*AB+0.4754*AC+0.1810*BC-0.4077*A2-0.3417*B2-0.2869*C2; Y2=12.37+0.7448*A+0.2547*B-0.130*C+0.0521*AB+0.4275*AC-0.1825*BC-0.7438*A2-0.5588*B2-0.6983*C2; Wherein, A is the ethanol concentration, B is the solid-liquid ratio, C is the extraction time, Y1 is the total phenolic acid extraction yield, and Y2 is the total flavonoid extraction yield; and The regression equation is calculated to obtain the extraction process of the quince complex.

2. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology according to claim 1, characterized in that: In step (3), the material-liquid ratio is 1 g:10 mL, 1 g:20 mL, 1 g:30 mL and 1 g:40 mL.

3. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince by response surface methodology according to claim 1, characterized in that: The ethanol concentrations are 0 v / v%, 50 v / v%, 60 v / v%, 70 v / v%, 80 v / v% and 90 v / v%.

4. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology according to claim 1, characterized in that: The ranges of the response variables are: the volume fraction of ethanol is 60%-80%; the solid-liquid ratio is 1g:(20 mL-40 mL); and the extraction time is 5 min-15 min.

5. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology according to claim 1, characterized in that: The method of collecting the extract includes centrifugation.

6. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology according to claim 5, characterized in that: The centrifugal parameters include: a rotation speed of 3500 r / min-4500 r / min and a time of 5 min-10 min.

7. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince by response surface methodology according to any one of claims 1 to 6, characterized in that: The frequency of ultrasonic treatment is 38 kHz -42 kHz, and the power is 280W -320W.

8. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince using response surface methodology according to any one of claims 1 to 6, characterized in that: The frequency of ultrasonic treatment was 40 kHz and the power was 300 W.

9. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince by response surface methodology according to any one of claims 1 to 6, characterized in that: The extraction process conditions for obtaining the quince complex include: ethanol concentration of 73.82 v / v%, solid-liquid ratio of 1:27.98, and extraction time of 11.36 min.

10. The process for optimizing the extraction of polyphenol-flavonoid complexes from quince by response surface methodology according to any one of claims 1 to 6, characterized in that: The pulverization process includes pulverization using a pulverizer.

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