Preparation method of whitening and anti-oxidation litchi peel extract as well as product and application of whitening and anti-oxidation litchi peel extract

Abstract

The invention relates to a preparation method, a product and application of a whitening and antioxidant litchi peel extract. The preparation method comprises the following steps: (1) mixing litchi peel powder with water, and carrying out ultrasonic extraction to obtain a litchi peel crude extract; (2) mixing the litchi peel crude extract with a compound enzyme, carrying out an enzymatic hydrolysis reaction, and carrying out enzyme deactivation treatment after the reaction to obtain an enzymatic hydrolysate; (3) performing cation exchange resin purification on the enzymatic hydrolysate to obtain a litchi pericarp extract; the compound enzyme in the step (2) comprises papain, bromelain and neutral protease. The litchi pericarp extract prepared by the invention has excellent antioxidant capacity and whitening effect, is safe and non-irritant, and is more beneficial to absorption by the human skin surface.

Description

Technical Field

[0001] The present invention belongs to the field of cosmetics, and particularly relates to a preparation method, product and application of a litchi pericarp extract with whitening and antioxidant effects. Background Art

[0002] Litchi is the fruit of the evergreen plant Litchi chinensis Sonn. in the family Sapindaceae, which is mainly produced in Guangdong, Guangxi, Fujian and other places in China. In recent years, it has developed rapidly, and the planting area of litchi has exceeded 3 million mu. However, during the deep processing of litchi, pericarp waste accounting for about 20% of the fresh fruit quality will be generated. Therefore, extracting effective components from litchi pericarp has great economic value.

[0003] Litchi pericarp itself contains a large amount of polyphenols, flavonoids, polysaccharides and rich vitamins, which can relieve skin inflammation and have good moisturizing, anti-inflammatory, antioxidant, whitening and other effects. However, due to different preparation methods of litchi pericarp extract, its whitening, antioxidant and other properties vary, the effect of litchi pericarp extract is affected to a certain extent, and the product application is also restricted.

[0004] CN103239546A discloses a method for extracting total flavonoids from litchi husk. After drying and crushing the waste litchi husk, ultrasonic extraction is carried out, followed by filtration and concentration, adsorption on a resin column, elution with an eluent, collection of the eluted solution, and drying to obtain natural total flavonoids.

[0005] CN117085361A discloses a method for extracting polyphenols from litchi husk by nitrogen protection and composite frequency ultrasonic assistance. On the one hand, high-low frequency ultrasonic and triple frequency ultrasonic treatments are carried out under low oxygen conditions to reduce the loss of polyphenol activity caused by oxidation; on the other hand, after replacing oxygen with nitrogen, the free radicals generated by the cleavage of dissolved oxygen molecules during the ultrasonic process are reduced, and the two effects combined achieve the purpose of protecting the activity of litchi husk polyphenol extract.

[0006] However, the effective components of the litchi pericarp extract prepared by the preparation methods disclosed in the prior art are single, and it is impossible to improve the effect of litchi pericarp extract from multiple dimensions. Therefore, preparing a litchi pericarp extract with multiple effects has become an urgent technical problem to be solved at present. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method, product and application of a litchi pericarp extract with whitening and antioxidant effects. The litchi pericarp extract prepared by this method has excellent antioxidant and whitening effects.

[0008] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0009] In a first aspect, the present invention provides a method for preparing a litchi pericarp extract with whitening and antioxidant effects, and the preparation method includes:

[0010] (1) Mix litchi pericarp powder with water and perform ultrasonic extraction to obtain a crude litchi pericarp extract;

[0011] (2) Mix the crude litchi pericarp extract with a complex enzyme for enzymatic hydrolysis reaction, and perform enzyme inactivation treatment after the reaction to obtain an enzymatic hydrolysate;

[0012] (3) Purify the enzymatic hydrolysate with a cation exchange resin to obtain a litchi pericarp extract;

[0013] The complex enzyme described in step (2) includes papain, bromelain and neutral protease.

[0014] The present invention first utilizes the cavitation effect, mechanical effect and thermal effect of ultrasonic waves to accelerate the diffusion of active ingredients in the pericarp into water, improve the extraction efficiency, and obtain a crude litchi pericarp extract; then through enzymatic hydrolysis reaction and cation exchange resin purification, the active ingredients are further released and purified to obtain a litchi pericarp extract with whitening and antioxidant effects.

[0015] In the present invention, bromelain, papain and neutral protease can destroy the protein components in the plant cell wall, refine the protein structure, thereby promoting the better release of whitening and antioxidant components in the cells.

[0016] By using a complex enzyme including bromelain, papain and neutral protease, the present invention can enzymatically hydrolyze the crude litchi pericarp extract more comprehensively and efficiently through the synergistic action of multiple enzymes, generate products with appropriate sizes and structures, and ultimately improve the whitening and antioxidant effects of the litchi pericarp extract.

[0017] Preferably, the mass ratio of the litchi pericarp powder to water in step (1) is 1:(10 - 50).

[0018] Among them, the specific point values in 10 - 50 can be selected as 10, 20, 30, 40, 50, etc.

[0019] Preferably, the preparation method of the litchi pericarp powder includes: crushing the litchi pericarp to 60 - 90 mesh to obtain litchi pericarp powder.

[0020] Among them, the specific point values in 60 - 90 mesh can be selected as 60 mesh, 70 mesh, 80 mesh, 90 mesh, etc.

[0021] Preferably, the temperature of the ultrasonic extraction in step (1) is 40 - 60 °C, and the time is 40 - 90 min.

[0022] Preferably, the power of the ultrasonic extraction in step (1) is 100 - 200 W.

[0023] Among them, the specific point values within 40 - 60 °C can be selected from 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, 52 °C, 54 °C, 56 °C, 58 °C, 60 °C, etc.; the specific point values within 40 - 90 min can be selected from 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, etc.; the specific point values within 100 - 200 W can be selected from 100 W, 120 W, 140 W, 160 W, 180 W, 200 W, etc.

[0024] Preferably, after the ultrasonic extraction in step (1), it further includes adjusting the pH value of the product of the ultrasonic extraction.

[0025] The pH value adjustment is carried out in any one of the following two ways:

[0026] (a) Adjust the pH value of the product of the ultrasonic extraction to 3 - 4, let it stand, collect the precipitate, and obtain the crude extract of litchi pericarp;

[0027] (b) Adjust the pH value of the product of the ultrasonic extraction to 7 - 8, centrifuge to obtain the supernatant; adjust the pH value of the supernatant to 3 - 4, let it stand, and take the precipitate to obtain the crude extract of litchi pericarp.

[0028] Among them, the specific point values within pH 3 - 4 can be selected from 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, etc. The specific point values within pH 7 - 8 can be selected from 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, etc.

[0029] By adjusting the pH value of the product of the ultrasonic extraction in the present invention, the enrichment of the active ingredients in the litchi pericarp can be further improved.

[0030] Preferably, in the present invention, by performing two - time pH adjustment on the product of the ultrasonic extraction, the active ingredients are first dissolved under neutral - to - slightly - alkaline conditions and then precipitated under acidic conditions, thereby further separating the target components from impurities and increasing the effective content of the whitening and antioxidant active ingredients.

[0031] Preferably, the mass ratio of the crude extract of litchi pericarp to the composite enzyme in step (2) is (100 - 5000):(0.5 - 10).

[0032] Preferably, the mass ratio of papain, bromelain, and neutral protease is (0.5 - 5):(0.1 - 1):(1 - 10).

[0033] Among them, the specific point values in the range of 100 - 5000 can be selected as 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, etc.; the specific point values in the range of 0.5 - 10 can be selected as 0.5, 2, 3.5, 5, 6.5, 8, 9.5, 10, etc.; the specific point values in the range of 0.5 - 5 can be selected as 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, etc.; the specific point values in the range of 0.1 - 1 can be selected as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.; the specific point values in the range of 1 - 10 can be selected as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0034] Based on the synergistic relationship among papain, bromelain and neutral protease, when the three are compounded according to the above ratio, components with whitening and antioxidant effects can be more fully prepared.

[0035] Preferably, the temperature of the enzymatic hydrolysis reaction is 30 - 50 °C and the time is 1 - 3 h.

[0036] Among them, the specific point values in the range of 30 - 50 °C can be selected as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, etc.; the specific point values in the range of 1 - 3 h can be selected as 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc.

[0037] Preferably, the cation exchange resin in step (3) includes 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin.

[0038] In the present invention, when 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin are co-doped, they synergistically enhance the effect, can more comprehensively remove cations in the enzymatic hydrolysate, and improve the selectivity and effect of purification.

[0039] Preferably, the mass ratio of the 001×4 gel-type strongly acidic styrene-based cation exchange resin to the 001×7 gel-type strongly acidic styrene-based cation exchange resin is (1 - 10):(1 - 10).

[0040] Among them, the specific point values in the range of 1 - 10 can be selected as 1, 3, 5, 7, 9, 10, etc.

[0041] Preferably, the eluent for purification in step (3) includes water.

[0042] Preferably, before the cation exchange resin purification in step (3), ultrafiltration and thin-film concentration of the enzymatic hydrolysate are also included.

[0043] Preferably, the molecular weight cut-off of the ultrafiltration membrane is 1000-1500 Da, and it can be, for example, 1000 Da, 1100 Da, 1200 Da, 1300 Da, 1400 Da, 1500 Da, etc.

[0044] Preferably, the temperature of the thin-film concentration is 60-70 °C, and the time is 1-4 h.

[0045] Among them, the specific point values in 60-70 °C can be selected as 60 °C, 62 °C, 64 °C, 66 °C, 68 °C, 70 °C, etc., and the specific point values in 1-4 h can be selected as 1 h, 2 h, 3 h, 4 h, etc.

[0046] Preferably, after the purification with the cation exchange resin in step (3), it further includes decolorizing the product purified by the cation exchange resin.

[0047] In the second aspect, the present invention provides a litchi pericarp extract prepared by the preparation method of the litchi pericarp extract with whitening and antioxidant effects as described in the first aspect.

[0048] In the third aspect, the present invention provides an application of the litchi pericarp extract as described in the second aspect in cosmetics.

[0049] The numerical ranges described in the present invention not only include the above-listed point values, but also include any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the ranges.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The preparation method of the litchi pericarp extract involved in the present invention enriches a large number of active ingredients in the litchi pericarp. The prepared litchi pericarp extract has excellent antioxidant ability and whitening effect, is safe and non-irritating, and is more conducive to absorption on the human skin surface.

[0052] Furthermore, the combined action of the complex enzymes of bromelain, papain and neutral protease can enzymatically hydrolyze the crude litchi pericarp extract more comprehensively and efficiently, and finally improve the whitening and antioxidant effects of the litchi pericarp extract. At the same time, based on the synergistic relationship among the three, when papain, bromelain and neutral protease are compounded in a mass ratio of (0.5-5):(0.1-1):(1-10), the components with whitening and antioxidant effects can be prepared more fully.

[0053] Furthermore, by adjusting the pH value of the product obtained by ultrasonic extraction during the preparation process, the enrichment of active ingredients in litchi pericarp can be further improved. In addition, by adjusting the pH value of the product obtained by ultrasonic extraction twice, the active ingredients are first dissolved under neutral to slightly alkaline conditions and then precipitated under acidic conditions, thereby further separating the target components from impurities and increasing the effective content of whitening and antioxidant active ingredients.

[0054] Furthermore, during the purification of the enzymatic hydrolysate, 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin are co-doped, and their synergistic effect can further improve the selectivity and effect of purification and enhance the whitening and antioxidant effects of the crude litchi pericarp extract. Specific embodiments

[0055] To further elaborate on the technical means and effects adopted by the present invention, the following further illustrates the technical solution of the present invention in combination with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0056] The sources of each component / raw material in the following embodiments are shown in Table 1:

[0057] Table 1

[0058]

[0059] Example 1

[0060] This example provides a method for preparing a litchi pericarp extract, which includes the following steps:

[0061] (1) Place fresh litchi pericarp in an oven, bake it with hot air, cool it, and then crush it through an 80-mesh sieve to obtain litchi pericarp powder.

[0062] (2) Mix the crushed litchi pericarp powder with water at a mass ratio of 1:20, place it in an ultrasonic extractor for ultrasonic extraction, set the power of the ultrasonic wave to 160 W, the temperature to 50 °C, and extract for 60 min. Based on a volume of 100 mL after ultrasonic extraction, add 1 g of activated carbon with a particle size of 5 ± 0.5 mm for adsorption for 35 min.

[0063] (3) Adjust the pH value of the ultrasonic extraction product after activated carbon adsorption to 7.5, stir it, and centrifuge it at a speed of 8000 rpm for 10 min to collect the supernatant. Subsequently, adjust the pH value of the supernatant to 3.5, let it stand for 24 h, and collect the precipitate to obtain the crude litchi pericarp extract.

[0064] (4) Mix the crude extract of litchi pericarp with water at a mass ratio of 1:10, add a composite enzyme (the mass ratio of papain, bromelain and neutral protease is 1:0.5:3) accounting for 4.5% of the mass of the crude extract of litchi pericarp, and carry out an enzymatic hydrolysis reaction at 40 °C for 2 h to obtain an enzymatic hydrolysate; after the enzymatic hydrolysis reaction, raise the temperature to 80 °C and inactivate the enzyme for 30 min;

[0065] (5) After the enzymatic hydrolysate is inactivated, carry out ultrafiltration (the molecular weight cut-off is 1200 Da), and concentrate the filtrate by thin-film concentration at 65 °C for 2 h.

[0066] (6) Using water as the eluent, load the concentrated solution after thin-film concentration (calculated based on 1000 mL of the concentrated solution, the dosage of the cation exchange resin is 1000 g) onto a cation exchange resin (using 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin doped in a mass ratio of 1:1) for purification to remove cations and obtain an eluate;

[0067] (7) Based on the system after removing cations being 100 mL, add 1.5 g of activated carbon with a particle size of 2±0.5 mm for adsorption, and the adsorption time is 40 min to obtain the litchi pericarp extract after adsorption.

[0068] Example 2

[0069] This example provides a preparation method of litchi pericarp extract, including the following steps:

[0070] (1) Place the fresh litchi pericarp in an oven, bake it with hot air, and after cooling, crush it and pass through a 60-mesh sieve to obtain litchi pericarp powder.

[0071] (2) Mix the crushed litchi pericarp powder with water at a mass ratio of 1:10, place it in an ultrasonic extractor for ultrasonic extraction, set the power of the ultrasonic wave to 100 W, the temperature to 40 °C, and carry out ultrasonic extraction for 90 min; based on the volume after ultrasonic extraction being 100 mL, add 0.5 g of activated carbon with a particle size of 4.5±0.5 mm for adsorption, and the time is 30 min.

[0072] (3) Adjust the pH value of the ultrasonic extraction product after activated carbon adsorption to 7, stir and then centrifuge at a speed of 7000 rpm for 6 min, collect the supernatant, and then adjust the pH value of the supernatant to 3, let it stand for 24 h, and collect the precipitate to obtain the crude extract of litchi pericarp.

[0073] (4) Mix the crude extract of litchi pericarp with water at a mass ratio of 1:10, add a composite enzyme (papain, bromelain, and neutral protease with a mass ratio of 1:1:1) accounting for 1% of the mass of the crude extract of litchi pericarp, and carry out an enzymatic hydrolysis reaction at 30 °C for 3 h to obtain an enzymatic hydrolysate; after the enzymatic hydrolysis reaction, raise the temperature to 80 °C and inactivate the enzyme for 30 min;

[0074] (5) After the enzymatic hydrolysate is inactivated, perform ultrafiltration (the molecular weight cut-off is 1000 Da), and carry out thin-film concentration on the filtrate for 3 h at 60 °C.

[0075] (6) Using water as the eluent, load the concentrated solution after thin-film concentration (calculated based on 1000 mL of the concentrated solution, the dosage of the cation exchange resin is 1000 g) onto a cation exchange resin (a 001×4 gel-type strongly acidic styrene-based cation exchange resin and a 001×7 gel-type strongly acidic styrene-based cation exchange resin are doped at a mass ratio of 1:5) for purification to remove cations and obtain an eluate;

[0076] (7) Based on the system after removing cations being 100 mL, add 1 g of activated carbon with a particle size of 1.5 ± 0.5 mm for adsorption, and the adsorption time is 30 min. After adsorption, obtain the litchi pericarp extract.

[0077] Example 3

[0078] This example provides a preparation method of a litchi pericarp extract, including the following steps:

[0079] (1) Place the fresh litchi pericarp in an oven, bake it with hot air, and after cooling, crush it and pass it through a 90-mesh sieve to obtain litchi pericarp powder.

[0080] (2) Mix the crushed litchi pericarp powder with water at a mass ratio of 1:50, place it in an ultrasonic extractor for ultrasonic extraction, set the power of the ultrasonic wave to 200 W, the temperature to 40 °C, and extract ultrasonically for 40 min; based on the volume after ultrasonic extraction being 100 mL, add 1 g of activated carbon with a particle size of 6 ± 0.5 mm for adsorption, and the time is 40 min.

[0081] (3) Adjust the pH value of the ultrasonic extraction product after activated carbon adsorption to 8, stir it, and centrifuge it at a speed of 6000 rpm for 6 min to collect the supernatant. Subsequently, adjust the pH value of the supernatant to 4, let it stand for 24 h, and collect the precipitate to obtain the crude extract of litchi pericarp.

[0082] (4) Mix the crude extract of litchi pericarp with water at a mass ratio of 1:10, add a composite enzyme (the mass ratio of papain, bromelain and neutral protease is 3:1:5) accounting for 10% of the mass of the crude extract of litchi pericarp, and carry out an enzymatic hydrolysis reaction at 50 °C for 1 h to obtain an enzymatic hydrolysate; after the enzymatic hydrolysis reaction, raise the temperature to 80 °C and inactivate the enzyme for 30 min;

[0083] (5) After the enzymatic hydrolysate is inactivated, carry out ultrafiltration (the molecular weight cut-off is 1500 Da), and carry out thin-film concentration on the filtrate for 1 h at 70 °C.

[0084] (6) Using water as the eluent, load the concentrated solution after thin-film concentration (calculated by 1000 mL of concentrated solution, the dosage of cation exchange resin is 1000 g) onto a cation exchange resin (using 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin doped according to a mass ratio of 5:1) for purification to remove cations and obtain an eluate;

[0085] (7) Based on the system after removing cations being 100 mL, add 2 g of activated carbon with a particle size of 3 ± 0.5 mm for adsorption, the adsorption time is 50 min, and a litchi pericarp extract is obtained after adsorption.

[0086] Example 4

[0087] This example provides a preparation method of a litchi pericarp extract, the difference from Example 1 is only that in step (3), the pH value of the ultrasonic extraction product after activated carbon adsorption is adjusted to 9, stirred and then centrifuged, the supernatant is collected, then, the pH value of the supernatant is adjusted to 5, left standing for 24 h, and the precipitate is collected to obtain the crude extract of litchi pericarp; the remaining steps are the same as those in Example 1.

[0088] Example 5

[0089] This example provides a preparation method of a litchi pericarp extract, the difference from Example 1 is only that in step (3), the pH value of the ultrasonic extraction product after activated carbon adsorption is adjusted to 6, stirred and then centrifuged, the supernatant is collected, then, the pH value of the supernatant is adjusted to 2, left standing for 24 h, and the precipitate is collected to obtain the crude extract of litchi pericarp; the remaining steps are the same as those in Example 1.

[0090] Example 6

[0091] This example provides a preparation method of a litchi pericarp extract, the difference from Example 1 is only that in step (3), only one pH value adjustment is carried out, that is, the pH value of the ultrasonic extraction product after activated carbon adsorption is adjusted to 3.5, left standing for 24 h, and the precipitate is collected to obtain the crude extract of litchi pericarp; the remaining steps are the same as those in Example 1.

[0092] Example 7

[0093] This example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that the pH value adjustment in step (3) is not carried out. After the activated carbon adsorption in step (2), a complex enzyme accounting for 0.45% of the mass of the ultrasonic extraction product after adsorption is directly added for enzymatic hydrolysis reaction, and the remaining steps are the same as those in Example 1.

[0094] Example 8

[0095] This example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that the mass ratio of papain, bromelain and neutral protease in step (4) is adjusted to 6:10:1, and the remaining steps are the same as those in Example 1.

[0096] Example 9

[0097] This example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that in step (6), the total mass of the cation exchange resin remains unchanged, and only the 001×4 gel-type strongly acidic styrene-based cation exchange resin is used for purification, and the remaining steps are the same as those in Example 1.

[0098] Example 10

[0099] This example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that in step (6), the total mass of the cation exchange resin remains unchanged, and only the 001×7 gel-type strongly acidic styrene-based cation exchange resin is used for purification, and the remaining steps are the same as those in Example 1.

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that in step (4), the total mass of the complex enzyme remains unchanged, and the components of the complex enzyme are adjusted to papain and bromelain with a mass ratio of 1:0.5, and the remaining steps are the same as those in Example 1.

[0102] Comparative Example 2

[0103] This comparative example provides a method for preparing a litchi pericarp extract. The difference from Example 1 is only that in step (4), the total mass of the complex enzyme remains unchanged, and the components of the complex enzyme are adjusted to papain and neutral protease with a mass ratio of 1:3, and the remaining steps are the same as those in Example 1.

[0104] Comparative Example 3

[0105] This comparative example provides a method for preparing litchi pericarp extract, and the difference from Example 1 is only that in step (4), the total mass of the complex enzyme remains unchanged, and the components of the complex enzyme are adjusted to bromelain and neutral protease with a mass ratio of 0.5:3, and the remaining steps are the same as those in Example 1.

[0106] Application Example 1

[0107] This application example provides a facial cream, which, by mass percentage, includes 5% of the litchi pericarp extract prepared in Example 1, 10% of polydimethylsiloxane, 4% of squalane, 5% of isocetane, 3% of glycerol, 5% of butanediol, 3% of hyaluronic acid, 5% of glyceryl stearate, and the balance is water.

[0108] Application Examples 2 - 10

[0109] Application Examples 2 - 10 each provide a facial cream, and the difference from Application Example 1 is only that the litchi pericarp extract prepared in Example 1 is replaced with the litchi pericarp extracts prepared in Examples 2 - 10.

[0110] Comparative Application Examples 1 - 3

[0111] Comparative Application Examples 1 - 3 each provide a facial cream, and the difference from Application Example 1 is only that the litchi pericarp extract prepared in Example 1 is replaced with the litchi pericarp extracts prepared in Comparative Examples 1 - 3.

[0112] Test Example 1

[0113] (1) Evaluation of DPPH free radical scavenging ability:

[0114] (1.1) Principle:

[0115] DPPH (1,1 - diphenyl - 2 - picrylhydrazyl) is commonly used for the in vitro antioxidant evaluation of antioxidants. DPPH is a stable nitrogen - centered free radical containing a single electron, with a maximum light absorption at 517 nm, and its alcohol solution is purple. When there is a free radical scavenger, the DPPH free radical accepts an electron and its light absorption gradually disappears, and the solution color changes from dark purple to yellow. The degree of fading is quantitatively related to the number of electrons it accepts (i.e., the free radical scavenging activity), so it can be quickly quantitatively analyzed with a spectrophotometer. That is, the stronger the scavenging ability of the free radical scavenger, the smaller the absorbance of DPPH.

[0116] (1.2) Steps:

[0117] Take 1.0 mL of the litchi pericarp extracts prepared in each example and comparative example (diluted 5 times) respectively, place them in 10 mL centrifuge tubes, add 3.0 mL of DPPH solution (0.008 mmol / L), react in the dark at room temperature for 30 min. At the same time, use absolute ethanol as the blank and measure the absorbance at 517 nm. Calculate the DPPH free radical scavenging rate according to the following formula.

[0118] DPPH free radical scavenging rate = A 0 -(As - Ac) / A 0 ×100%;

[0119] In the formula, A 0 is the absorbance of 1.0 mL of distilled water + 3.0 mL of DPPH solution, As is the absorbance of 1.0 mL of sample solution + 3.0 mL of DPPH solution, and Ac is the absorbance of 1.0 mL of sample solution + 3.0 mL of absolute ethanol.

[0120] (2) Evaluation of ABST free radical scavenging ability:

[0121] (2.1) Principle:

[0122] ABTS (2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) can be oxidized by K 2 S 2 O 8 to generate blue-green ABTS + free radicals, which have the maximum light absorption at 734 nm. ABTS + is quite stable, but in the presence of antioxidants, ABTS + reacts with it to generate colorless ABTS.

[0123] (2.2) Procedure:

[0124] Take 0.1 mL of the litchi pericarp extracts prepared in each example and comparative example (diluted 5 times) respectively, add 0.1 mL of absolute ethanol, mix well, then add 0.8 mL of ABTS+ solution (0.1 mmol / L), mix thoroughly and let stand for 6 min. At the same time, use absolute ethanol as the blank and measure the absorbance at 734 nm. Calculate the ABTS free radical scavenging rate according to the following formula.

[0125] ABTS free radical scavenging rate = (A 0 - A) / A 0 ×100%;

[0126] In the formula, A 0 is the absorbance of 0.2 mL of distilled water + 0.8 mL of ABTS+ solution, and A is the absorbance of 0.2 mL of sample solution + 0.8 mL of ABTS+ solution.

[0127] The free radical scavenging abilities of the litchi pericarp extracts prepared in each example and comparative example are shown in Table 2.

[0128] Table 2

[0129]

[0130]

[0131] From the test data in Table 2, it can be seen that the litchi pericarp extract involved in the present invention has excellent DPPH free radical scavenging activity and ABTS free radical scavenging activity.

[0132] From the data comparison between Example 1 and Comparative Examples 1-3, it can be seen that during the preparation process of the litchi pericarp extract, papain, bromelain and neutral protease cooperate with each other and synergistically enhance the effect, and can better enzymatically hydrolyze the crude litchi pericarp extract, improving the antioxidant effect of the litchi pericarp extract.

[0133] From the data comparison between Example 1 and Examples 4-7, it can be seen that by adjusting the pH value of the product of ultrasonic extraction, the enrichment of active ingredients in the litchi pericarp can be further improved; by adjusting the pH of the crude litchi pericarp extract twice, the active ingredients are first dissolved under neutral to slightly alkaline conditions and then precipitated under acidic conditions, which can better enrich the effective content of antioxidant functional ingredients and improve the antioxidant ability of the crude litchi pericarp extract.

[0134] From the data comparison between Example 1 and Example 8, it can be seen that based on the synergistic relationship among papain, bromelain and neutral protease, when the three are compounded in a mass ratio of (0.5-5):(0.1-1):(1-10), the antioxidant ability of the prepared crude litchi pericarp extract can be further improved.

[0135] From the data comparison between Example 1 and Examples 9-10, it can be seen that during the purification process, when the cation exchange resin selects a co-doping of 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin, the selectivity and effect of purification can be better improved, thereby enhancing the antioxidant ability of the prepared crude litchi pericarp extract.

[0136] Test Example 2

[0137] Whitening effect evaluation:

[0138] (1) Subjects: 65 healthy women (30-45 years old), divided into 13 groups, with 5 people in each group; the products of Application Examples 1-10 and Comparative Application Examples 1-3 were used respectively, and the usage amounts of each product were equal.

[0139] (2) The whitening effect of the skin care product is measured using a skin colorimeter and a skin melanin detector. A skin colorimeter is an instrument that can measure the L*a*b* color space data defined by the International Commission on Illumination (CIE). The parameters characterizing the color of human skin are measured by a skin colorimeter or a reflection spectrophotometer to obtain the L*a*b* color space data of the skin. The calculation formula is as follows:

[0140] ITA° = {arctan(L* - 50) / b*} 180 / π.

[0141] A skin melanin detector is an instrument that detects the MI value of the skin based on the principle of spectral absorption.

[0142] (3) Test procedure: The test area is the face. No products (cosmetics or topical medications) can be used on the test site 3 days before the test, and no water can be contacted 3 hours before the test. Before the experiment, the subjects need to clean their facial skin uniformly, sit still in a laboratory at a temperature of 21 ± 1°C and a relative humidity of 50 ± 10% for 30 minutes, during which no water or beverages can be consumed. The subjects should remain relaxed. After 30 minutes, the laboratory technician conducts the test on the subjects, and then guides the subjects to use the product. The same evaluation and test are carried out again at the 8th week. Use a skin colorimeter to measure the L*, a*, and b* values of the skin in the pigmented area of the test site. Each test area is measured three times, and the ITA° value is recorded and calculated. The larger the ITA° value of the test skin area, the lighter the skin color, and vice versa. Use a skin melanin tester to measure the MI value of the skin in the pigmented area of the test site. Each test area is measured three times and recorded; the smaller the MI value of the test area, the lighter the skin color, and vice versa.

[0143] The test results of the whitening effect of each test group are shown in Table 3.

[0144] Table 3

[0145]

[0146]

[0147] From the test data in Table 3, it can be seen that the litchi pericarp extract involved in the present invention can well regulate skin color and has excellent whitening effect.

[0148] From the data comparison between Application Example 1 and Comparative Application Examples 1 - 3, it can be seen that during the preparation process of the litchi pericarp extract, papain, bromelain, and neutral protease cooperate with each other and synergistically enhance the effect, enabling better enzymatic hydrolysis of the crude litchi pericarp extract and improving the whitening effect of the litchi pericarp extract.

[0149] From the data comparison between Application Example 1 and Application Examples 4 - 7, it can be seen that by adjusting the pH value of the product extracted by ultrasound, the enrichment of active ingredients in litchi pericarp can be further improved; through two - step pH adjustment of the crude extract of litchi pericarp, enabling the active ingredients to dissolve first under neutral - to - slightly - alkaline conditions and then precipitate under acidic conditions, the active ingredients with whitening effects can be better enriched, and the whitening effect of the crude extract of litchi pericarp can be enhanced.

[0150] From the data comparison between Application Example 1 and Application Example 8, it can be seen that based on the synergistic relationship among papain, bromelain, and neutral protease, when the three are compounded in a mass ratio of (0.5 - 5):(0.1 - 1):(1 - 10), the whitening effect of the prepared crude extract of litchi pericarp can be further improved.

[0151] From the data comparison between Application Example 1 and Application Examples 9 - 10, it can be seen that during the purification process, when the cation - exchange resin selects a co - doping of 001×4 gel - type strongly acidic styrene - based cation - exchange resin and 001×7 gel - type strongly acidic styrene - based cation - exchange resin, the selectivity and effect of purification can be better improved, thereby enhancing the whitening effect of the prepared crude extract of litchi pericarp.

[0152] Test Example 3

[0153] Safety evaluation:

[0154] Select the same 65 subjects as in Test Example 2, and conduct the following safety evaluation test on this batch of subjects: After cleaning the subjects' backs, apply the patch tester with the sample on the selected position on the back with non - irritating tape. After pasting, gently press it with fingers to make it evenly adhere to the skin and keep it for 48 h. The subjects should keep the patch area dry within 48 h, and avoid strenuous exercise, scratching the patch area, and long - term sunlight exposure, etc. After 48 h, remove the tester and make marks. After 30 min, when the indentation disappears, make a judgment under sufficient light.

[0155] The grading standard for skin adverse reactions is shown in Table 4:

[0156] Table 4

[0157]

[0158]

[0159] The safety test results are shown in Table 5:

[0160] Table 5

[0161]

[0162] As can be seen from the data in Table 5, the subjects in different test groups all had negative reactions, indicating that the litchi pericarp extract prepared by the present invention is safe, mild and non-irritating to the skin.

[0163] The applicant declares that the technical solution of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

[0164] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0165] In addition, it should be noted that in the above specific embodiments, the various specific technical features described can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A method for preparing a whitening and antioxidant litchi peel extract, characterized in that: The preparation method comprises: (1) mixing litchi peel powder with water and performing ultrasonic extraction to obtain a crude litchi peel extract; (2) mixing the crude extract of litchi peel with a composite enzyme to perform an enzymatic hydrolysis reaction, and performing an enzyme inactivation treatment after the reaction to obtain an enzymatic hydrolyzate; (3) purifying the enzymatic hydrolyzate with a cation exchange resin to obtain a litchi peel extract; The complex enzyme in step (2) comprises papain, bromelain and neutral protease.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the litchi peel powder to water in step (1) is 1:(10-50); Preferably, the preparation method of the litchi peel powder comprises: crushing the litchi peel into 60-90 meshes to obtain the litchi peel powder.

3. The preparation method according to claim 1 or 2, characterized in that: The temperature of the ultrasonic extraction in step (1) is 40-60°C and the time is 40-90min; Preferably, the power of the ultrasonic extraction in step (1) is 100-200W.

4. The preparation method according to any one of claims 1 to 3, characterized in that After the ultrasonic extraction in step (1), the method further comprises adjusting the pH value of the ultrasonically extracted product; The pH value adjustment is performed in either of the following two ways: (a) adjusting the pH value of the product extracted by ultrasonic extraction to 3-4, allowing it to stand, collecting the precipitate, and obtaining a crude extract of litchi peel; (b) adjusting the pH value of the ultrasonically extracted product to 7-8, centrifuging, and obtaining a supernatant; adjusting the pH value of the supernatant to 3-4, allowing the supernatant to stand, and collecting a precipitate to obtain a crude extract of litchi peel.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The mass ratio of the crude lychee peel extract to the complex enzyme in step (2) is (100-5000):(0.5-10); Preferably, the mass ratio of papain, bromelain and neutral protease is (0.5-5):(0.1-1):(1-10); Preferably, the temperature of the enzymatic hydrolysis reaction is 30-50°C and the time is 1-3h.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The cation exchange resin in step (3) includes 001×4 gel-type strongly acidic styrene-based cation exchange resin and 001×7 gel-type strongly acidic styrene-based cation exchange resin; Preferably, the mass ratio of the 001×4 gel-type strongly acidic styrene-based cation exchange resin to the 001×7 gel-type strongly acidic styrene-based cation exchange resin is (1-10):(1-10); Preferably, the purified eluent in step (3) comprises water.

7. The preparation method according to any one of claims 1 to 6, characterized in that: Before the cation exchange resin purification in step (3), the enzymatic hydrolyzate is further subjected to ultrafiltration and membrane concentration; Preferably, the ultrafiltration membrane has a molecular weight cutoff of 1000-1500Da; Preferably, the thin film concentration is carried out at a temperature of 60-70° C. and for a time of 1-4 hours.

8. The preparation method according to any one of claims 1 to 7, characterized in that: After the cation exchange resin purification in step (3), the method further includes decolorizing the product purified by the cation exchange resin.

9. A litchi peel extract prepared by the method for preparing the whitening and antioxidant litchi peel extract according to any one of claims 1 to 8.

10. Use of the litchi peel extract according to claim 9 in cosmetics.

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