Immature bitter orange polyphenol extract as well as extraction method and optimization method thereof

Abstract

The invention discloses an immature bitter orange polyphenol extract as well as an extraction method and an optimization method thereof, and relates to the technical field of plant extraction. The extraction method comprises the following steps: S1, taking immature bitter orange as a raw material, and performing ultrasonic-assisted extraction by using ethanol to obtain a crude extract; s2, adding the crude extract into water, heating to dissolve the crude extract, cooling, adding absolute ethyl alcohol, standing, and centrifuging to remove precipitate to obtain a concentrated solution; and S3, carrying out dynamic adsorption and desorption on the concentrated solution by using resin, eluting by using ethanol, collecting the eluent, and concentrating to obtain the product. According to the method, parameters such as ethanol volume fraction, liquid-solid ratio, ultrasonic time, power and temperature are optimized through a response surface analysis method, the most suitable resin is screened out for further purification, the method has the advantages of high yield, low cost and environmental protection, efficient and green extraction preparation of the total phenols of the immature bitter oranges is achieved, the naringin content in the extract is higher than 50 g / 100 g, and the method is suitable for industrial production. The content of neohesperidin is higher than 10g / 100g.

Description

Technical Field

[0001] The present invention relates to the technical field of plant extraction, and particularly relates to an extract of Fructus Aurantii Polyphenols, its extraction method and optimization method. Background Art

[0002] As a traditional Chinese medicinal material, Fructus Aurantii has been widely studied because it contains rich flavonoid compounds such as naringin, neohesperidin, etc. Especially the polyphenol components therein have significant antioxidant activity, can effectively scavenge free radicals, and reduce the damage of oxidative stress to cells. In addition, studies have shown that Fructus Aurantii also has various biological activities such as regulating blood lipids and improving cardiovascular function, making it an ideal raw material for developing new health foods.

[0003] However, the traditional extraction process of Fructus Aurantii Polyphenols usually has problems such as low efficiency, high energy consumption and environmental pollution. For example, although the hot water extraction method is simple to operate, the extraction rate is low; the organic solvent extraction method may cause residual pollution and high cost. Therefore, exploring an efficient and environmentally friendly extraction and separation process is of great significance for improving the utilization rate of Fructus Aurantii resources and the added value of its products. Summary of the Invention

[0004] The purpose of the present invention is to at least solve one of the technical problems existing in the prior art, and provide an extract of Fructus Aurantii Polyphenols, its extraction method and optimization method, specifically to provide an efficient and green method for extracting and separating Fructus Aurantii Polyphenols.

[0005] The technical solution of the present invention is as follows: The first aspect of the present invention provides an extraction method for an extract of Fructus Aurantii Polyphenols, comprising the following steps: S1. Using Fructus Aurantii as a raw material, ultrasonic-assisted extraction is carried out using ethanol as a solvent to obtain a crude extract; S2. Adding the crude extract to water, heating to dissolve the crude extract, cooling, adding absolute ethanol and standing, centrifuging to remove the precipitate, and obtaining a concentrated solution; S3. Dynamically adsorbing and resolving the concentrated solution using a resin, eluting with ethanol, collecting the eluate and concentrating to obtain an extract of Fructus Aurantii Polyphenols.

[0006] Preferably, in step S1, the volume fraction of ethanol is 10 - 60%, the liquid-solid ratio of ethanol to Fructus Aurantii is 10 - 25 mL:1 g, the ultrasonic time is 10 - 40 minutes, the ultrasonic power is 200 - 500 W, and the ultrasonic temperature is 20 - 70 °C.

[0007] More preferably, in step S1, the volume fraction of ethanol is 30%, the liquid-solid ratio of ethanol to Fructus Aurantii is 10 mL:1 g, the ultrasonic time is 30 minutes, the ultrasonic power is 450 W, and the ultrasonic temperature is 60 °C.

[0008] Preferably, in step S2, the liquid-to-solid ratio of water to crude extract is 8-12 mL:1 g, the heating temperature is 30-80°C, the heating time is 3-5 h, and the amount of anhydrous ethanol added is 3-5 times the volume of the mixture of crude extract and water after heating and cooling.

[0009] Preferably, in step S3, the resin is one of X-5, HPD-750, AB-8, D101 and XDA-8, the loading solution concentration is 10~20 g / L, the loading rate is 0.7~5 BV / h, the volume fraction of ethanol is 10~60%, and the elution flow rate is 1~4 BV / h.

[0010] More preferably, in step S3, the resin is D101, the concentration of the loading solution is 14 g / L, the loading rate is 0.7 BV / h, the volume fraction of ethanol is 60%, and the elution flow rate is 1 BV / h.

[0011] Preferably, the extraction method further includes a preliminary purification step of the extract, by adjusting the pH value or using other physicochemical methods to remove impurities.

[0012] Preferably, the extraction method further includes a quality testing step for the final product, including but not limited to tests for total phenol content, flavonoid content, heavy metal residue, and microbial limits.

[0013] A second aspect of the present invention provides a polyphenolic extract of Citrus aurantium obtained by the extraction method, the polyphenolic extract comprising the following components: polysaccharides, proteins, fats, dietary fiber, calcium, iron, zinc, vitamin B2, naringin, neohesperidin, ash, and water.

[0014] Preferably, the content of naringin is higher than 50g / 100g, and the content of neohesperidin is higher than 10g / 100g.

[0015] Preferably, the nutritional quality index (INQ) of the Citrus aurantium product is 0.29. A third aspect of the present invention provides a method for optimizing the extraction parameters of Citrus aurantium polyphenol extract based on response surface methodology, comprising the following steps: Based on step S1 above, single-factor experiments were conducted using the volume fraction of ethanol, the liquid-solid ratio of ethanol to immature bitter orange, ultrasonic time, ultrasonic power, and ultrasonic temperature. Based on the single-factor experiment, the three most influential factors, ultrasonic temperature, ultrasonic power and ultrasonic time, were selected as independent variables, and the total phenol yield was used as the response value to establish a quadratic multiple regression equation. Response surface methodology was performed on the quadratic multiple regression equation. The total phenol yield was taken as the maximum value, and the extraction process of the Citrus aurantium polyphenol extract was optimized to obtain the optimal extraction process parameters.

[0016] Preferably, the quadratic multiple regression equation is: Y = 5.45936 + 0.518881 * A + 0.12869 * B - 0.187934 * C - 0.0928829 * AB + 0.126302 * AC - 0.014323 * BC - 0.277252 * A 2 -0.714752 * B 2 -0.809804 * C 2 Where Y is the total phenol yield of Citrus aurantium, A is the influence of ultrasonic temperature, B is the influence of ultrasonic power, and C is the influence of ultrasonic time.

[0017] Preferably, through response surface methodology experiments using Design-Expert software on three factors at three levels—ultrasound time, ultrasound power, and ultrasound temperature—the optimal conditions were determined to be: ultrasound time of 29 min, ultrasound power of 450 W, and ultrasound temperature of 68 ℃. Under these conditions, the total phenolic yield of Citrus aurantium can reach 5.71%.

[0018] This invention has at least one of the following beneficial effects: 1. This invention provides a method for efficiently and environmentally friendly extraction and separation of polyphenols from Citrus aurantium, including optimized ultrasound-assisted extraction conditions and purification using macroporous resin D101. Extraction parameters, including ethanol volume fraction, liquid-to-solid ratio, ultrasound time, power, and temperature, were optimized using response surface methodology. The most suitable macroporous resin D101 was selected for further purification. The extraction method and optimization method of this invention have the advantages of high yield, low cost, and environmental friendliness.

[0019] 2. This invention achieves efficient and green extraction and preparation of total phenols from Citrus aurantium. The Citrus aurantium polyphenol extract contains polysaccharides, proteins, fats, dietary fiber, calcium, iron, zinc, vitamin B2, naringin, neohesperidin, ash, and water. Among them, the naringin content is higher than 50g / 100g, and the neohesperidin content is higher than 10g / 100g. Therefore, the total phenol content is high. Attached Figure Description

[0020] Figure 1 This describes the effect of ethanol volume fraction on the total phenol content extracted from Citrus aurantium as described in Example 1 of the present invention.

[0021] Figure 2 This describes the effect of the liquid-to-solid ratio on the total phenol content extracted from Citrus aurantium as described in Example 1 of the present invention.

[0022] Figure 3 This describes the effect of ultrasonic time on the total phenol content extracted from Citrus aurantium as described in Example 1 of the present invention.

[0023] Figure 4 This describes the effect of ultrasonic power on the total phenol content extracted from Citrus aurantium as described in Example 1 of the present invention.

[0024] Figure 5 This describes the effect of ultrasonic temperature on the total phenol content extracted from Citrus aurantium as described in Example 1 of the present invention.

[0025] Figure 6 This is a surface diagram of ultrasonic power versus ultrasonic temperature response as described in Embodiment 2 of the present invention.

[0026] Figure 7 This is the ultrasonic time and ultrasonic temperature response surface diagram described in Embodiment 2 of the present invention.

[0027] Figure 8 This is the ultrasonic time and ultrasonic power response surface diagram described in Embodiment 2 of the present invention.

[0028] Figure 9 The adsorption rate of various macroporous resins described in Example 3 of this invention is the adsorption rate after 24 hours.

[0029] Figure 10 The adsorption rate of various macroporous resins described in Example 3 of this invention is the adsorption rate over 6 hours.

[0030] Figure 11 This describes the effect of the concentration of the loading solution on the adsorption of D101 type resin as described in Example 3 of the present invention.

[0031] Figure 12 This describes the effect of the loading flow rate on the adsorption of D101 type resin as described in Example 3 of the present invention.

[0032] Figure 13 This describes the effect of ethanol concentration on the desorption of D101 type resin as described in Example 3 of the present invention.

[0033] Figure 14 This describes the effect of the elution flow rate on the desorption of D101 type resin as described in Example 3 of the present invention. Detailed Implementation

[0034] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] Example 1: Single-factor optimization experiment S1. Take 1 g of Citrus aurantium sample and use ethanol as solvent for ultrasonic-assisted extraction to obtain crude extract; S2. Add the above crude extract to water at a liquid-to-solid ratio of 10:1 (mL:g), heat in a water bath at 80 °C for 4 hours, and after cooling, add 4 times the volume of anhydrous ethanol, let stand overnight, and centrifuge to remove polysaccharides to obtain a concentrated Citrus aurantium extract solution.

[0036] Using the total phenol content in the concentrated extract of Citrus aurantium as an indicator, the effects of ethanol volume fraction, liquid-to-solid ratio, ultrasonic time, ultrasonic power, and ultrasonic temperature on the total phenol content during ultrasonic-assisted extraction in step S1 were determined. The method for determining the total phenol content was as follows: The sample was diluted with methanol to an appropriate concentration, within the concentration range of the gallic acid standard; 20 μL of the diluted sample was incubated with 0.1 mL of Folin-Ciocalteau reagent for 5 minutes, followed by the addition of 0.3 mL of 7.5% Na₂CO₃ and 1.0 mL of distilled water. The mixture was shaken thoroughly and incubated at room temperature for 30 minutes; after incubation, the sample was centrifuged at 10,000 rpm for 1 minute, and 200 μL of the supernatant was transferred to a 96-well plate, with the absorbance measured at 765 nm. The total phenol content was calculated based on a calibration curve plotted using gallic acid as a standard. The total polyphenol content in the extract was expressed as equivalent to gallic acid.

[0037] The specific optimization methods are as follows: (1) Effect of ethanol volume fraction on total phenol content: Under conditions of an ethanol-to-fragrant orange fruit liquid-solid ratio of 20:1 (mL:g), ultrasonic power of 300 W, ultrasonic time of 30 min, and ultrasonic temperature of 30 ℃, the ethanol volume fraction was varied (10%, 30%, 50%, 70%, 90%). The total phenol content was used as the indicator, and the results are as follows: Figure 1 As shown, according to Figure 1 The optimal ethanol volume fraction for ultrasonic-assisted extraction was determined to be 30%.

[0038] (2) Effect of liquid-to-solid ratio on total phenol content: Under the conditions of 30% ethanol volume fraction, 300 W ultrasonic power, 30 min ultrasonic time, and 30 ℃ ultrasonic temperature, the liquid-solid ratio of ethanol to immature bitter orange was varied (10:1, 15:1, 20:1, 25:1, 30:1 mL:g). The total phenol content was used as the indicator, and the results are as follows: Figure 2 As shown, according to Figure 2 The optimal liquid-solid ratio for ultrasonic-assisted extraction was determined to be 10:1 (mL:g).

[0039] (3) Effect of ultrasound time on total phenol content: Under the conditions of 30% ethanol volume fraction, 300 W ultrasonic power, 10:1 (mL:g) liquid-to-solid ratio of ethanol to immature bitter orange, and 30 ℃ ultrasonic temperature, the ultrasonic time was varied (10 min, 20 min, 30 min, 40 min, 50 min). The total phenol content was used as the indicator, and the results are as follows: Figure 3 As shown, according to Figure 3 The optimal ultrasonic time for ultrasonic-assisted extraction was determined to be 30 minutes.

[0040] (4) Effect of ultrasonic power on total phenol content: Under the conditions of 30% ethanol (volume fraction), 30 min ultrasonic time, 30 ℃ ultrasonic temperature, and a liquid-to-solid ratio of ethanol to immature bitter orange (mL:g), the ultrasonic power was varied (350 W, 400 W, 450 W, 500 W). The total phenol content was used as the indicator, and the results are as follows: Figure 4 As shown, according to Figure 4 The optimal ultrasonic power for ultrasonic-assisted extraction was determined to be 450 W.

[0041] (5) Effect of ultrasonic temperature on total phenol content: Under the conditions of 30% ethanol (volume fraction), 30 min ultrasonic time, 450 W ultrasonic power, and a liquid-to-solid ratio of 10:1 (mL:g), the ultrasonic temperature was varied (40 ℃, 50 ℃, 60 ℃, 70 ℃). The total phenol content was used as the indicator, and the results are as follows: Figure 5 As shown, according to Figure 5 The optimal ultrasonic temperature for ultrasonic-assisted extraction was determined to be 60 ℃.

[0042] Example 2: Response Surface Methodology Optimization Experiment Based on the single-factor experimental results in Example 1, the extraction process of Citrus aurantium was further optimized using the response surface methodology. A three-factor, three-level response surface experiment with ultrasonic time, ultrasonic power, and ultrasonic time was designed using Design Expert 13. The design and results of the response surface experiment are shown in Table 1.

[0043] Table 1. Response surface methodology experimental design and results The total phenol yield of Citrus aurantium = total phenol content (g) / weight of Citrus aurantium sample (g).

[0044] The operating parameters and experimental results studied in the response surface methodology are shown in Table 2. Table 2 summarizes the effects of independent factors on the yield of polyphenols from Citrus aurantium. The quadratic regression equation model for the total phenol yield as the response value is as follows: Y=5.45936 + 0.518881 * A + 0.12869 * B - 0.187934 * C -0.0928829 * AB+ 0.126302 * AC -0.014323 * BC -0.277252 * A 2 - 0.714752 * B 2 -0.809804 * C 2 ; Where Y is the total phenol yield of Citrus aurantium, A is the influence of ultrasonic temperature, B is the influence of ultrasonic power, and C is the influence of ultrasonic time.

[0045] The quadratic regression model showed good significance, and the lack-of-fit term was not significant, indicating that the model can be used in the experiment.

[0046] Table 2 Analysis of Response Surface Experiment Results Based on the response surface results ( Figure 6-8 The feasibility of the model was confirmed. Therefore, the experimental parameters were further optimized using Design-Expert software. The optimal conditions were found to be: ultrasonic time of 29 min, ultrasonic power of 450 W, and ultrasonic temperature of 68 ℃. Under these conditions, the total phenol yield of Citrus aurantium can reach 5.71%, which is basically consistent with the model prediction of 5.70%.

[0047] In summary, the optimal extraction conditions for total phenols from Citrus aurantium were: 30% ethanol (v / v), a liquid-to-solid ratio of 10:1 (mL:g), an ultrasonic time of 29 min, an ultrasonic power of 450 W, and an ultrasonic temperature of 68 ℃. To remove polysaccharides, water was added at a liquid-to-solid ratio of 10:1 (mL:g), and the mixture was heated in a water bath at 80 ℃ for 4 h. After cooling, four times the volume of anhydrous ethanol was added, and the mixture was allowed to stand overnight. After centrifugation to remove polysaccharides, the Citrus aurantium extract solution was concentrated.

[0048] Example 3: Screening and purification of macroporous resins The Citrus aurantium extract solution obtained in step S2 of Example 1 was concentrated and purified to obtain the final product, Citrus aurantium polyphenol extract. The specific method is as follows: 1. Screening of macroporous resins: Different types of macroporous adsorption resins (X-5, HPD-750, AB-8, D101, and XDA-8) were taken and placed in 100 mL Erlenmeyer flasks. 10 mL of crude *Citrus aurantium* extract (dissolved in distilled water) with an initial concentration of 10 g / L was added. The total phenol concentration of the supernatant was measured after 24 h, and the adsorption rate was calculated. The resins after static adsorption were filtered and placed in 100 mL Erlenmeyer flasks. 10 mL of 95% ethanol-water was added, and the total phenol concentration of the supernatant was measured after 6.0 h, and the desorption rate was calculated. Based on... Figure 9-10 The adsorption and desorption effects demonstrated led to the selection of type D101 macroporous resin.

[0049] 2. Separation and purification process: The obtained concentrate was subjected to dynamic adsorption and desorption using D101 macroporous resin. The concentration of the loading solution was 6~22 g / L, the loading rate was 0.7~5 BV / h, and elution was performed with 10~60% ethanol at a flow rate of 1~4 BV / h.

[0050] The effects of sample concentration, sample loading rate, ethanol concentration, and elution flow rate on adsorption were determined, and the results are as follows: (1) Effect of sample concentration on adsorption: Figure 11 The results showed that, by controlling different initial mass concentrations (6, 10, 14, 18, 22 g / L) and a loading flow rate of 0.7 BV / h for dynamic adsorption, the optimal loading solution concentration was determined to be 14 g / L.

[0051] (2) Effect of sample loading flow rate on adsorption: Figure 12 The results showed that, with the sample concentration controlled at 14 g / L and the sample flow rates at 0.7, 1, 2, 3, 4, and 5 BV / h for dynamic adsorption, the optimal sample flow rate was determined to be 0.7 BV / h.

[0052] (3) Effect of ethanol concentration on desorption: Figure 13 The results showed that after dynamic adsorption with a loading solution concentration of 14 g / L and a loading flow rate of 0.7 BV / h, elution with ethanol of different volume concentrations (20%, 40%, 60%, and 80%) showed that the 60% ethanol solution had the best elution effect.

[0053] (4) Effect of elution flow rate on desorption: Figure 14 The results showed that after dynamic adsorption with a loading concentration of 14 g / L and a loading flow rate of 0.7 BV / h, elution with 60% ethanol solution at different flow rates (0.7, 1, 2, 3, 4 BV / h) determined the optimal elution flow rate to be 1 BV / h.

[0054] In summary, the optimal separation and purification process is as follows: dynamic adsorption and desorption are performed using D101 macroporous resin, with a sample concentration of 14 g / L and a sample loading flow rate of 0.7 BV / h, followed by elution with 60% ethanol solution at a flow rate of 1 BV / h.

[0055] Example 4: Structural composition of nutrients in Citrus aurantium extract A highly efficient and environmentally friendly process for extracting and separating polyphenols from Citrus aurantium includes the following steps: S1. Using 40% ethanol as solvent, ultrasonic-assisted extraction was performed at a liquid-to-solid ratio of 10:1 (mL:g), an ultrasonic time of 40 minutes, an ultrasonic power of 450W, and an ultrasonic temperature of 60℃. S2. Add the above extract to water at a liquid-to-solid ratio of 10:1 (mL:g), heat in a water bath at 80°C for 4 h, and after cooling, add 4 times the volume of anhydrous ethanol, let stand overnight, centrifuge to remove polysaccharides, and obtain concentrated Citrus aurantium extract solution. S3. Dynamic adsorption and desorption of the obtained concentrate were performed using D101 macroporous resin at a loading concentration of 14 g / L and a loading rate of 0.7 BV / h. The concentrate was eluted with 60% ethanol at a flow rate of 1 BV / h. The eluent was collected and concentrated to obtain the final Citrus aurantium polyphenol extract.

[0056] The content of nutrients such as protein, vitamins, fat, polysaccharides, trace elements, and dietary fiber in the polyphenol extract of Citrus aurantium was determined with reference to national food safety standards GB 5009.5-2016, GB 5009.88-2014, GB 5009.6-2016, and GB5009.92-2016. Chromatographic and spectroscopic methods were used to determine the small molecule compounds—naringin and neohesperidin—and their contents in the Citrus aurantium extract. The specific structural composition and proportions of the polyphenol extract are shown in Table 3.

[0057] Table 3: Composition and content of polyphenol extract from Citrus aurantium Example 5: The difference from Example 4 is that the parameters of ultrasonic-assisted extraction in S1 are changed, while the other steps are the same as in Example 4. The specific parameters of ultrasonic-assisted extraction are as follows: ethanol volume fraction of 50%, liquid-solid ratio of 15:1 (mL:g), ultrasonic time of 20 min, ultrasonic power of 400 W, and ultrasonic temperature of 50 ℃.

[0058] The composition and content of the polyphenol extract of Citrus aurantium obtained in this embodiment are shown in Table 4.

[0059] Table 4. Composition, structure, and content of the polyphenol extract of Citrus aurantium after changing the ultrasonic power. Example 6: The difference from Example 4 is that the separation and purification parameters in S3 are changed, while the other steps are the same as in Example 4. The specific separation and purification parameters are as follows: D101 macroporous resin, sample concentration 10 g / L, sample loading flow rate 1 BV / h, 40% ethanol solution elution, elution flow rate 0.7 BV / h.

[0060] The composition and content of the polyphenol extract of Citrus aurantium obtained in this embodiment are shown in Table 5.

[0061] Table 5. Composition, structure, and content of the polyphenol extract of Citrus aurantium after changing separation and purification parameters. The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for extracting polyphenols from Citrus aurantium, characterized in that, Includes the following steps: S1. Using Citrus aurantium as raw material, ultrasonic-assisted extraction was performed using ethanol as solvent to obtain crude extract; S2. Add the crude extract to water, heat to dissolve the crude extract, cool, add anhydrous ethanol, let stand, centrifuge to remove the precipitate, and obtain a concentrated solution. S3. The concentrate is dynamically adsorbed and desorbed using resin, eluted with ethanol, the eluent is collected and concentrated to obtain the Citrus aurantium polyphenol extract.

2. The extraction method according to claim 1, characterized in that, In step S1, the volume fraction of ethanol is 10-60%, the liquid-solid ratio of ethanol to immature bitter orange is 10-25 mL:1 g, the ultrasonic time is 10-40 minutes, the ultrasonic power is 200-500 W, and the ultrasonic temperature is 20-70℃.

3. The extraction method according to claim 1, characterized in that, In step S1, the volume fraction of ethanol is 30%, the liquid-solid ratio of ethanol to immature bitter orange is 10 mL: 1 g, the ultrasonic time is 30 minutes, the ultrasonic power is 450 W, and the ultrasonic temperature is 60 °C.

4. The extraction method according to claim 1, characterized in that, In step S2, the liquid-to-solid ratio of water to crude extract is 8-12 mL:1 g, the heating temperature is 30-80℃, the heating time is 3-5 h, and the amount of anhydrous ethanol added is 3-5 times the volume of the mixture of crude extract and water after heating and cooling.

5. The extraction method according to claim 1, characterized in that, In step S3, the resin is one of X-5, HPD-750, AB-8, D101 and XDA-8, the concentration of the loading solution is 10~20 g / L, the loading rate is 0.7~5 BV / h, the volume fraction of ethanol is 10~60%, and the elution flow rate is 1~4 BV / h.

6. The extraction method according to claim 1, characterized in that, In step S3, the resin is D101, the concentration of the loading solution is 14 g / L, the loading rate is 0.7 BV / h, the volume fraction of ethanol is 60%, and the elution flow rate is 1 BV / h.

7. The *Citrus aurantium* polyphenol extract obtained by any one of the extraction methods described in claims 1 to 6, characterized in that, The Citrus aurantium polyphenol extract includes the following components: polysaccharides, proteins, fats, dietary fiber, calcium, iron, zinc, vitamin B2, naringin, neohesperidin, ash, and water.

8. The Fructus Aurantii Immaturus polyphenol extract according to claim 7, characterized in that, The content of naringin is higher than 50g / 100g, and the content of neohesperidin is higher than 10g / 100g.

9. A method for optimizing extraction parameters of Citrus aurantium polyphenol extract based on response surface methodology, characterized in that, Includes the following steps: Based on step S1 of claim 1, single-factor experiments were conducted by selecting the volume fraction of ethanol, the liquid-solid ratio of ethanol to immature bitter orange, the ultrasonic time, the ultrasonic power, and the ultrasonic temperature. Based on the single-factor experiment, the three most influential factors, ultrasonic temperature, ultrasonic power and ultrasonic time, were selected as independent variables, and the total phenol yield was used as the response value to establish a quadratic multiple regression equation. Response surface methodology was performed on the quadratic multiple regression equation, and the total phenol yield was taken as the maximum value. The extraction method in step S1 of claim 1 was then optimized to obtain the optimal extraction process parameters.

10. The method according to claim 9, characterized in that, The quadratic multiple regression equation is: Y = 5.45936 + 0.518881 * A + 0.12869 * B - 0.187934 * C - 0.0928829 * AB + 0.126302 * AC - 0.014323 * BC - 0.277252 * A 2 - 0.714752* B 2 -0.809804 * C 2 Where Y is the total phenol yield of Citrus aurantium, A is the influence of ultrasonic temperature, B is the influence of ultrasonic power, and C is the influence of ultrasonic time. The optimal extraction process parameters are: ultrasonic time of 29 min, ultrasonic power of 450 W, and ultrasonic temperature of 68 ℃.

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