Citrus peel extract with soothing effect as well as preparation method and application thereof

Abstract

The invention relates to a citrus peel extract with a soothing effect and a preparation method and application thereof, and belongs to the technical field of cosmetics. The invention provides a preparation method of a citrus peel extract, which comprises the following steps: degreasing citrus peel by using a supercritical CO2 extraction technology to obtain degreased citrus peel; mixing the degreased citrus peel with water to obtain a citrus peel suspension, and mixing the citrus peel suspension with a compound enzyme preparation for enzymolysis to obtain the citrus peel subjected to enzymolysis; and filtering the orange peel after enzymolysis, collecting filtrate, performing ultrafiltration treatment, and collecting fractions with the molecular weight of less than 10kDa to obtain the orange peel extract. The citrus peel is degreased through a supercritical CO2 extraction technology, volatile grease and fat-soluble impurities in the citrus peel can be removed, the components in the citrus peel are further enzymatically hydrolyzed into small-molecule active substances through enzymolysis with a compound enzyme preparation, skin absorption is facilitated, and the soothing and whitening effects of the citrus peel extract are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the cosmetic technology field, and in particular to a citrus peel extract with soothing effect, and a preparation method and application thereof. BACKGROUND

[0002] The citrus peel is rich in various bioactive components, such as flavonoids (hesperidin, naringin, etc.), limonoids and volatile oils, etc. These components have been proven to have antioxidant, anti-inflammatory, whitening and soothing skin effects, etc.

[0003] At present, the extraction process of the citrus peel extract is mainly through alcohol extraction combined with acid precipitation and alkali dissolution process, which can extract flavonoids and alkaloids in the citrus peel. In addition, the citrus extract is obtained by using percolation extraction, macroporous resin adsorption, ion exchange column chromatography, multiple acid-base adjustment and recrystallization extraction. The above extraction processes have the following shortcomings: 1. Complex preparation process conditions lead to increased loss rate: multiple acid-base adjustment may cause structural changes of some pH-sensitive active ingredients (such as some flavonoid glycosides with soothing effect and vitamin C with whitening effect), thereby degrading or inactivating them; 2. Single effect of the citrus peel extract: only a certain type of specific active ingredients in the citrus peel is extracted, which may result in a single effect of the extract, and it is difficult to meet the current demand of the cosmetic market for multi-effect raw materials; 3. Greater environmental pollution: a large amount of organic alcohol, petroleum ether, n-hexane and other solvents are used in the extraction process, which has certain harmfulness to the environment and a large burden on the environment, thereby increasing the cost.

[0004] Therefore, it is urgent to develop a citrus peel extract with multiple effects and a more environmentally friendly extraction process. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a citrus peel extract with soothing effect, and a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: In a first aspect, the present application provides a preparation method of a citrus peel extract, comprising the following steps: S1. Using supercritical CO2 extraction technology to perform defatting treatment on the citrus peel to obtain defatted citrus peel; S2. Mixing the defatted citrus peel obtained in step S1 with water to obtain a citrus peel suspension, mixing the citrus peel suspension with a complex enzyme preparation, and performing enzymolysis for 2-3 hours, then performing enzyme inactivation treatment, centrifuging to collect the supernatant, and obtaining the supernatant as the enzymolyzed citrus peel; S3, filtering the enzymolysis citrus peel obtained in step S2, collecting the filtrate and then performing ultrafiltration treatment, and collecting a fraction with a molecular weight <10 kDa, the fraction with a molecular weight <10 kDa obtained being a citrus peel extract.

[0007] The present application can remove volatile oil and fat-soluble impurities from the citrus peel by using supercritical CO2 extraction technology to perform defatting treatment on the citrus peel, and the inert CO2 environment can prevent the oxidation of the chemically reactive components in the citrus peel; the use of complex enzyme preparation for enzymolysis can improve the extraction efficiency of active substances, and further enzymolyze the components in the citrus peel into small-molecule active substances, which are beneficial to skin absorption, and the use of ultrafiltration membrane to enrich small-molecule active substances can effectively improve the soothing and whitening effects of the citrus peel extract.

[0008] As a preferred embodiment of the preparation method of the present application, in step S1, the parameter conditions of the supercritical CO2 extraction technology are: extraction pressure 25-35 MPa, extraction temperature 40-50℃, and extraction time 1-2 h.

[0009] As a preferred embodiment of the preparation method of the present application, in step S1, the parameter conditions of the supercritical CO2 extraction technology are: extraction pressure 30 MPa, extraction temperature 45℃, and extraction time 1.5 h.

[0010] As a preferred embodiment of the preparation method of the present application, in step S1, the citrus peel is citrus peel powder passing through a 40-80 mesh screen.

[0011] As a preferred embodiment of the preparation method of the present application, in step S2, the ratio of the defatted citrus peel to water is: defatted citrus peel: water = 1 g: (10-15) mL.

[0012] As a preferred embodiment of the preparation method of the present application, in step S2, the addition amount of the complex enzyme preparation is 0.3-0.6 mg of complex enzyme preparation per 1 mL of citrus peel suspension.

[0013] As a preferred embodiment of the preparation method of the present application, in step S2, the addition amount of the complex enzyme preparation is 0.4-0.5 mg of complex enzyme preparation per 1 mL of citrus peel suspension.

[0014] As a preferred embodiment of the preparation method of the present application, in step S2, the complex enzyme preparation comprises at least one of cellulase, pectinase and β-glucosidase. The present application can synergistically improve the soothing and whitening effects of the citrus peel extract by using cellulase, pectinase and β-glucosidase as a complex enzyme preparation.

[0015] As a preferred embodiment of the preparation method of the present application, in step S2, when the complex enzyme preparation is cellulase, pectinase and beta-glucosidase, the mass ratio of the cellulase, pectinase and beta-glucosidase is cellulase:pectinase:beta-glucosidase= (3-10) : (2-6) : 1. The present application finds through experiments that cellulase, pectinase and beta-glucosidase have better effects of improving the soothing and whitening effects of citrus peel extract within a specific ratio range.

[0016] As a preferred embodiment of the preparation method of the present application, in step S2, the mass ratio of the cellulase, pectinase and beta-glucosidase is cellulase:pectinase:beta-glucosidase= (4-8) : (3-5) : 1.

[0017] As a preferred embodiment of the preparation method of the present application, in step S2, the mass ratio of the cellulase, pectinase and beta-glucosidase is cellulase:pectinase:beta-glucosidase= (5-7) : (3-4) : 1.

[0018] As a preferred embodiment of the preparation method of the present application, in step S2, the mass ratio of the cellulase, pectinase and beta-glucosidase is cellulase:pectinase:beta-glucosidase= 6:4:1.

[0019] As a preferred embodiment of the preparation method of the present application, in step S2, the enzymolysis condition is pH=4.5-5.5, enzymolysis temperature 35-45℃, and enzymolysis time 2-3h.

[0020] As a preferred embodiment of the preparation method of the present application, in step S2, the enzymolysis condition is pH=5, enzymolysis temperature 48℃, and enzymolysis time 2.5h.

[0021] As a preferred embodiment of the preparation method of the present application, in step S2, the enzyme inactivation treatment is standing at 85-90℃ for 10-15min.

[0022] As a preferred embodiment of the preparation method of the present application, in step S3, the filtration is filtration in a microfiltration membrane, and the pore size of the microfiltration membrane is 0.1-0.2μm.

[0023] As a preferred embodiment of the preparation method of the present application, in step S3, the microfiltration membrane is a ceramic microfiltration membrane.

[0024] As a preferred embodiment of the preparation method of the present application, in step S3, the ultrafiltration treatment is ultrafiltration in an ultrafiltration membrane, and the molecular weight cut-off of the ultrafiltration membrane is <10kDa.

[0025] As a preferred embodiment of the preparation method of the present application, in step S3, the molecular weight cut-off of the ultrafiltration membrane is 1-9.9 kDa.

[0026] As a preferred embodiment of the preparation method of the present application, in step S3, the molecular weight cut-off of the ultrafiltration membrane is 2-9 kDa. The molecular weight cut-off of the ultrafiltration membrane can also be at least one of 3 kDa, 4 kDa, 5 kDa, 6 kDa, 7 kDa, 8 kDa, and 9 kDa.

[0027] As a preferred embodiment of the preparation method of the present application, the preparation method further comprises the following steps: S4, concentrating and drying the fraction with a molecular weight <10 kDa obtained in step S3 to obtain a high-purity citrus peel extract.

[0028] As a preferred embodiment of the preparation method of the present application, in step S4, the concentration is at least one of vacuum thin film concentration and freeze concentration.

[0029] As a preferred embodiment of the preparation method of the present application, in step S4, the drying is at least one of freeze drying and spray drying.

[0030] In a second aspect, the present application provides a citrus peel extract, which is mainly prepared by the above preparation method.

[0031] The citrus peel extract of the present application is experimentally proved to have excellent soothing and whitening effects.

[0032] In a third aspect, the present application provides the use of the above citrus peel extract in the preparation of soothing and whitening cosmetics.

[0033] Compared with the prior art, the present application has the following beneficial effects: The present application can remove volatile oils and fat-soluble impurities from the citrus peel by using supercritical CO2 extraction technology for defatting the citrus peel, and the inert CO2 environment can prevent the oxidation of the chemically reactive components in the citrus peel; the use of a complex enzyme preparation for enzymatic hydrolysis can improve the extraction efficiency and further hydrolyze the components in the citrus peel into small-molecule active substances, which are beneficial to skin absorption, and the enrichment of small-molecule active substances by using an ultrafiltration membrane can effectively improve the soothing and whitening effects of the citrus peel extract. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 Product diagram of the citrus peel extract obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0035] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0036] Unless otherwise specified, all other materials and reagents used in the examples, comparative examples, and effect examples are commercially available.

[0037] Example 1 This embodiment provides a citrus peel extract with soothing effects and its preparation method, the preparation method including the following steps: (1) After passing the dried citrus peel through a 40-80 mesh sieve, citrus peel powder is obtained and transferred into a reaction vessel. Supercritical CO2 is introduced into the reaction vessel, and the extraction pressure is adjusted to 25 MPa, the extraction temperature to 40℃, and the extraction time to 2 h to obtain defatted citrus peel. (2) Prepare a citrus peel suspension by mixing citrus peel with water at a ratio of 10 mL of water per 1 g of defatted citrus peel obtained in step (1); (3) The citrus peel suspension obtained in step (2) was mixed with compound enzyme preparation 1 at a ratio of 0.3 mg per 1 mL of citrus peel suspension obtained in step (2). The pH was adjusted to 4.5, and the mixture was enzymatically hydrolyzed at 45°C for 3 h. The temperature was then raised to 90°C and held for 10 min to inactivate the enzyme. The mixture was cooled to room temperature (25±3°C), and the supernatant was collected by centrifugation. The supernatant obtained was the citrus peel after enzymatic hydrolysis. The components and ratios of the compound enzyme preparation 1 are shown in Table 1. (4) The enzymatically hydrolyzed citrus peel obtained in step (3) is filtered through a ceramic microfiltration membrane with a pore size of 0.2 μm to obtain the filtrate; (5) The filtrate obtained in step (4) is ultrafiltered using a spiral wound ultrafiltration membrane with a molecular weight cutoff of 10 kDa. The fraction with a molecular weight < 10 kDa is a citrus peel extract. (6) The citrus peel extract obtained in step (5) is transferred to a vacuum thin film concentrator and concentrated at 50°C to a solid content of 20-30%. Then it is transferred to a spray dryer and spray dried at an inlet temperature of 150°C and an outlet temperature of 80°C to obtain a high-purity citrus peel extract.

[0038] The obtained citrus peel extract, when mixed with water, forms an orange-yellow solution (see...). Figure 1 ).

[0039] Table 1. Components and mass ratios of the compound enzyme preparation Example 2 This embodiment provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 2. The composition of compound enzyme preparation 2 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0040] Example 3 This embodiment provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Embodiment 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 3. The composition of compound enzyme preparation 3 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0041] Example 4 This embodiment provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that in Example 1, except that in step (3), the amount of the compound enzyme preparation 1 is 0.5 mg of compound enzyme preparation added to every 1 mL of citrus peel suspension obtained in step (2).

[0042] Example 5 This embodiment provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that in embodiment 2, except that in step (1), the extraction pressure is 30 MPa, the extraction temperature is 50 °C, and the extraction time is 1 h. In step (2), 15 mL of water is added to every 1 g of defatted citrus peel obtained in step (1); In step (4), the pore size of the ceramic microfiltration membrane is 0.1 μm; In step (6), the inlet temperature of the spray dryer is 160°C and the outlet temperature is 85°C. The remaining steps and their parameters remain unchanged.

[0043] Comparative Example 1 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 4. The composition of compound enzyme preparation 4 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0044] Comparative Example 2 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 5. The composition of compound enzyme preparation 5 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0045] Comparative Example 3 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 6. The composition of compound enzyme preparation 6 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0046] Comparative Example 4 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 7. The composition of compound enzyme preparation 7 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0047] Comparative Example 5 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is replaced with compound enzyme preparation 8. The composition of compound enzyme preparation 8 is shown in Table 1. The remaining steps and parameters remain unchanged.

[0048] Comparative Example 6 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (1), dried citrus peel is passed through a 40-80 mesh sieve to obtain citrus peel powder. The citrus peel powder is mixed and stirred evenly with a ratio of 1g:5mL petroleum ether solution and placed in a round-bottom flask. It is then refluxed at 50-60℃ for 60min and extracted twice. After combining the extracts, the petroleum ether containing volatile oil is recovered by rotary evaporation. The citrus peel in the round-bottom flask is collected and evaporated to dryness to obtain defatted citrus peel. The remaining steps and parameters remain unchanged.

[0049] Comparative Example 7 This comparative example provides a citrus peel extract with soothing effects and its preparation method. The preparation method is similar to that of Example 1, except that in step (3), the compound enzyme preparation 1 is not added, and the other steps and parameters are the same.

[0050] Example 1 To evaluate the whitening efficacy of the citrus peel extracts in Examples 1-5 and Comparative Examples 1-7, cell experiments were conducted on the above-mentioned citrus peel extracts, and the specific procedures are as follows: 1. The citrus peel extract obtained in Example 1 was dissolved in DMEM high-glucose basal medium to prepare solutions of different concentrations. Using B16 mouse melanoma cells as the experimental subject, the cell density was adjusted to 1×10⁻⁶ cells / year. 5Cells were cultured at a concentration of 1.5 mL / well in 6-well plates for 20-24 hours. The cell culture medium was then replaced with sample-containing medium (2 mL / well), and cultured for another 48 hours. The negative control group was treated with cell culture medium containing solvent. 240 μL of MTT solution was added to each well, and cultured for another 4-6 hours. After terminating the culture, the supernatant was discarded, and 2.4 mL of DMSO was added to each well. The plates were shaken to dissolve the crystals completely. The absorbance of each well was measured at 570 nm using an ELISA reader, and cell viability was calculated. The results are shown in Table 2.

[0051] Table 2 Effects of different concentrations of citrus peel extract on B16 cell viability As shown in Table 2, the survival rate of B16 cells was over 90% when the concentration of citrus peel extract was 78.13 and 156.25 μg / mL. Therefore, 78.13 μg / mL of citrus peel extract was selected for the experiment.

[0052] 2. Adjust cell density to 1.0 × 10⁻⁶ 5 Cells were cultured at a density of 1.5 mL / well in 6-well plates and incubated at 37°C with 5% CO2 for 20-24 hours. The cell culture medium was then replaced with 2 mL / well containing the sample, and the plates were incubated for another 48 hours. The negative control group received cell culture medium containing solvent, while the positive control group received cell culture medium containing 50 μg / mL kojic acid. Cells were washed twice with PBS, the PBS was removed, and 200 μL of 0.25% trypsin was added to each well to digest the cells. The cells were then incubated in a CO2 incubator for 5 minutes. Cells were collected by pipetting 2 mL of PBS in two separate portions and centrifuged at 4000 rpm for 5 minutes. The remaining PBS in the centrifuge tubes was removed, and 200 μL of melanin extraction solution was added to each tube. The tubes were shaken well and heated in an 80°C water bath for 1 hour. After cooling, the liquid droplets on the tube wall were centrifuged moderately, and the mixture was blown evenly. 150 μL of the solution from each centrifuge tube was transferred into a 96-well plate, and the absorbance at 405 nm in each well was measured using an ELISA reader. The results are shown in Table 3.

[0053] The formula for calculating the melanin synthesis inhibition rate is: Inhibition rate (%) = (CT) / (C-C0) × 100%, where C is the average absorbance of the negative control group, C0 is the average background absorbance of the melanin extract, and T is the average absorbance of the sample or positive control.

[0054] Table 3. Inhibition rate of melanin synthesis in cells under different treatments (average) As shown in Table 3, the citrus peel extracts obtained in Examples 1-5 have a good inhibitory effect on melanin synthesis, indicating that the content of active ingredients in citrus peel extracts can be effectively increased by supercritical CO2 extraction technology and enzymatic hydrolysis with compound enzyme preparations.

[0055] Compared with Comparative Examples 1-5, the citrus peel extract obtained in this example showed a higher melanin synthesis inhibition rate, indicating that the combination of cellulase, pectinase, and β-glucosidase as a complex enzyme preparation can synergistically improve the enzymatic hydrolysis efficiency of citrus peel, effectively increasing the content of active ingredients in the citrus peel extract and achieving the purpose of whitening. If other types of enzymes are added to the complex enzyme preparation, or if the ratio of cellulase, pectinase, and β-glucosidase is inappropriate, the melanin synthesis inhibition effect of the citrus peel extract obtained in this application cannot be obtained. This indicates that only when cellulase, pectinase, and β-glucosidase are in a specific ratio can a citrus peel extract with excellent whitening effect be prepared.

[0056] Compared with Comparative Examples 6-7, the citrus peel extract obtained in the examples showed a higher melanin synthesis inhibition rate, indicating that only by using supercritical CO2 extraction technology for defatting and enzymatic hydrolysis with compound enzyme preparations can citrus peel extract with excellent whitening effect be prepared.

[0057] Example 2 To evaluate the soothing effects of the citrus peel extracts in Examples 1-5 and Comparative Examples 1-6, cell experiments were conducted on the above-mentioned citrus peel extracts, and the specific protocol is as follows: 1. The citrus peel extract obtained in Example 1 was dissolved in DMEM high-glucose basal medium to prepare solutions of different concentrations. Mouse mononuclear macrophage leukemia cells (RAW264.7) were used as experimental subjects, and the cell density was adjusted to 5 × 10⁻⁶ cells / year. 4 A cell suspension of 200 μL / mL was seeded into 96-well plates and cultured for 20-24 h. The cell culture medium was then replaced with sample-containing medium (200 μL per well), and cultured for another 48 h. The negative control group was treated with cell culture medium containing solvent. 15 μL of MTT solution was added to each well, and cultured for another 4-6 h. After terminating the culture, the supernatant was discarded, and 150 μL of DMSO was added to each well. The cells were shaken in a shaker to dissolve the crystals completely. The absorbance of each well was measured at 570 nm using an ELISA reader, and cell viability was calculated. The results are shown in Table 4.

[0058] Table 4. Effects of different concentrations of citrus peel extract on the viability of RAW264.7 cells. As shown in Table 4, the survival rate of RAW264.7 cells was over 90% when the concentration of citrus peel extract was 312.5 μg / mL. Therefore, 78.13 μg / mL of citrus peel extract was selected for the experiment.

[0059] 2. Prepare 5×10 using culture medium. 4 Cell suspensions of 200 μL / mL were seeded into 96-well plates. After seeding, the plates were incubated in a CO2 incubator for 24 ± 2 h. The culture medium in the 96-well plates was discarded, and the drug administration procedure was carried out: culture medium containing different concentrations of citrus peel extract solution or solvent (negative control) or 100 μg / mL dexamethasone (positive control) was added to the test wells, and DMEM high-glucose basal medium was added to the blank control wells, 200 μL per well. After drug administration, the 96-well plates were incubated in a CO2 incubator for 24 ± 2 h. After incubation, the cell supernatant was collected, and 200 μL of cell culture supernatant was collected from each well into a sterile centrifuge tube and stored at -80℃. The TNF-α content of each group was detected according to the instructions of the mouse tumor necrosis factor α (TNF-α) ELISA kit. The results are shown in Table 5.

[0060] The formula for calculating the TNF-α inhibition rate is: Inhibition rate (%) = [1 - (T / C)] × 100%, where C is the average TNF-α content of the negative control group and T is the average TNF-α content of the sample or positive control.

[0061] Table 5. TNF-α inhibition rate (mean) of cells in different treatment groups As shown in Table 3, the citrus peel extracts obtained in Examples 1-5 have a good TNF-α inhibitory effect, indicating that the content of active ingredients in citrus peel extracts can be effectively increased by supercritical CO2 extraction technology and enzymatic hydrolysis with compound enzyme preparations.

[0062] Compared with Comparative Examples 1-5, the TNF-α inhibition rate of the citrus peel extract obtained in this example is higher, indicating that the combination of cellulase, pectinase, and β-glucosidase as a complex enzyme preparation can synergistically improve the enzymatic hydrolysis efficiency of citrus peel, effectively increasing the content of active ingredients in the citrus peel extract and achieving a soothing effect. If other types of enzymes are added to the complex enzyme preparation, or if the ratio of cellulase, pectinase, and β-glucosidase is inappropriate, the TNF-α inhibition effect of the citrus peel extract obtained in this application cannot be obtained. This indicates that only when cellulase, pectinase, and β-glucosidase are in a specific ratio can a citrus peel extract with excellent soothing effects be prepared.

[0063] Compared with Comparative Examples 6-7, the TNF-α inhibition rate of the citrus peel extract obtained in the examples was higher, indicating that only by using supercritical CO2 extraction technology for defatting and enzymatic hydrolysis with compound enzyme preparations can a citrus peel extract with excellent soothing effects be prepared. Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the present invention.

Claims

1. A method for preparing a citrus peel extract, characterized in that, Includes the following steps: S1. Supercritical CO2 extraction technology is used to degrease citrus peel to obtain degreased citrus peel; S2. Mix the defatted citrus peel obtained in step S1 with water to obtain a citrus peel suspension. Mix the citrus peel suspension with a compound enzyme preparation and enzymatically hydrolyze for 2-3 hours. After enzyme inactivation treatment, centrifuge and collect the supernatant. The supernatant obtained is the enzymatically hydrolyzed citrus peel. S3. Filter the enzymatically hydrolyzed citrus peel obtained in step S2, collect the filtrate and then perform ultrafiltration to collect the fraction with a molecular weight <10kDa. The fraction with a molecular weight <10kDa is the citrus peel extract.

2. The preparation method according to claim 1, characterized in that, In step S1, the parameters of the supercritical CO2 extraction technology are: extraction pressure 25-35 MPa, extraction temperature 40-50℃, and extraction time 1-2 h.

3. The preparation method according to claim 1, characterized in that, In step S2, the ratio of defatted citrus peel to water is defatted citrus peel: water = 1g: (10-15)mL.

4. The preparation method according to claim 1, characterized in that, In step S2, the amount of the compound enzyme preparation added is 0.3-0.6 mg of compound enzyme preparation per 1 mL of citrus peel suspension.

5. The preparation method according to claim 1, characterized in that, In step S2, the complex enzyme preparation includes at least one of cellulase, pectinase and β-glucosidase.

6. The preparation method according to claim 1, characterized in that, In step S2, when the compound enzyme preparation is cellulase, pectinase and β-glucosidase, the mass ratio of cellulase, pectinase and β-glucosidase is cellulase: pectinase: β-glucosidase = (3-10): (2-6):

1.

7. The preparation method according to claim 1, characterized in that, In step S2, the conditions for enzymatic hydrolysis are: pH = 4.5-5.5, enzymatic hydrolysis temperature 35-45℃, and enzymatic hydrolysis time 2-3h.

8. The preparation method according to claim 1, characterized in that, Includes at least one of the following (I) to (II): (I) In step S3, the filtration is performed in a microfiltration membrane, wherein the pore size of the microfiltration membrane is 0.1-0.2 μm; (II) In step S3, the ultrafiltration process is performed in an ultrafiltration membrane with a molecular weight cutoff of <10kDa.

9. A citrus peel extract with soothing effects, characterized in that, It is mainly prepared by the preparation method described in any one of claims 1-8.

10. The use of the citrus peel extract as described in claim 9 in the preparation of soothing and whitening cosmetics.

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