Whitening gel based on biological polysaccharide and preparation method thereof

Abstract

The invention relates to the technical field of gel materials, and discloses whitening gel based on biological polysaccharide and a preparation method thereof, the whitening gel comprises the following raw materials: hyaluronic acid, deionized water and thunberg fritillary bulb polysaccharide microcapsules; wherein the bulbus fritillariae thunbergii polysaccharide microcapsule is prepared by taking konjac glucomannan, chitosan and perillaldehyde modified hyaluronic acid as a shell layer and embedding bulbus fritillariae thunbergii polysaccharide and glabridin as a core material; the perillaldehyde modified hyaluronic acid is prepared by reacting alkenyl hyaluronic acid with perillaldehyde under the action of an initiator; the alkenyl hyaluronic acid is prepared by reacting hyaluronic acid with glycidyl methacrylate under the action of a catalyst. The prepared whitening gel has excellent whitening, moisturizing, anti-oxidation and anti-aging effects, effective components are not prone to loss, and the whitening gel can be applied to the skin surface for a long time, plays a whitening role and delays the aging process of the skin.

Description

Technical Field

[0001] The present invention relates to the technical field of gel materials, and in particular to a whitening gel based on biopolysaccharide and a preparation method thereof. Background Art

[0002] In modern society, with the accelerating pace of life and increasing environmental pollution, the skin, as the body's largest organ, is directly exposed to the external environment and is highly susceptible to damage. Problems such as dryness, dullness, and oxidation often occur, seriously accelerating the aging process. Therefore, whitening, moisturizing, and anti-aging have become important topics in the skincare field.

[0003] The main goal of whitening is to reduce the melanin content in the skin, making the skin tone more even and bright. Tyrosinase is the key enzyme in melanin synthesis. Inhibiting the activity of tyrosinase can effectively inhibit the formation of melanin, thereby achieving the effect of skin whitening. Anti-aging requires resisting the oxidative stress of the skin, that is, the skin cells are attacked by free radicals, resulting in damage to the cell structure and function. Free radicals are highly reactive and can attack cell membranes and proteins, triggering biochemical reactions, and ultimately accelerating the skin aging process.

[0004] Patent publication number CN108578300B discloses a skin care gel with a synergistic whitening effect, comprising the following ingredients: niacinamide, citrus peel extract, arbutin, whitening complex 1, whitening complex 2, and excipients. The combination of these components prevents the skin from receiving negative feedback signals due to a sudden increase in the signal of a certain whitening node, such as a decrease in melanin and the need for large-scale melanin production. It also inhibits tyrosinase activity, inhibits melanin transfer, and brightens the skin tone, achieving a safe, effective, and stable whitening effect. While this patent has an excellent whitening effect on the skin, its anti-aging capabilities need to be improved. Furthermore, the active ingredients in this patent are mostly small molecules that are easily lost during use, resulting in a short duration of action for the skin care gel. Summary of the Invention

[0005] The purpose of the present invention is to provide a whitening gel based on biopolysaccharides and a preparation method thereof, which solves the problems that existing whitening gels have general melanin inhibition effects, rapid loss of effective ingredients, lack of antioxidant effects, and are difficult to delay skin aging.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A whitening gel based on biopolysaccharides comprises the following raw materials in parts by weight: 50-80 parts of hyaluronic acid, 100-150 parts of deionized water, and 15-20 parts of thunbergii fritillary polysaccharide microcapsules; the thunbergii fritillary polysaccharide microcapsules are prepared by using konjac glucan, chitosan, and perillaldehyde-modified hyaluronic acid as a shell layer, and embedding thunbergii fritillary polysaccharide and glabridin as a core material; the perillaldehyde-modified hyaluronic acid is prepared by reacting olefinated hyaluronic acid with perillaldehyde under the action of an initiator; and the olefinated hyaluronic acid is prepared by reacting hyaluronic acid with glycidyl methacrylate under the action of a catalyst.

[0008] Furthermore, the preparation method of the Fritillaria thunbergii polysaccharide comprises the following steps:

[0009] Weigh the coarse powder of Fritillaria thunbergii medicinal material, add deionized water to mix, perform ultrasonic extraction, filter, concentrate the filtrate, add ethanol, stir thoroughly, let stand, centrifuge, and freeze-dry the precipitate to obtain Fritillaria thunbergii polysaccharide.

[0010] By ultrasonically extracting the coarse powder of Fritillaria thunbergii, the Fritillaria thunbergii polysaccharide obtained contains rich mucus, mucin, amino acids and other ingredients, which can effectively moisturize and lock in moisture, soothe the skin, and also have anti-oxidation and anti-aging effects, effectively slowing down the aging process of the skin.

[0011] Furthermore, the temperature of the ultrasonic extraction is 60-65° C., and the time is 30-40 minutes.

[0012] Furthermore, the preparation method of the perillaldehyde-modified hyaluronic acid comprises the following steps:

[0013] S1: Place hyaluronic acid and glycidyl methacrylate in deionized water, stir thoroughly, add a catalyst, heat to 65-75°C, stir for 10-15 hours, and collect the product after reduced pressure distillation to obtain olefinated hyaluronic acid;

[0014] S2: Place the olefinated hyaluronic acid in anhydrous ethanol, mix and stir thoroughly, add perillaldehyde and initiator, raise the temperature to 50-55°C and react for 6-8 hours, and collect the product after reduced pressure distillation to obtain perillaldehyde-modified hyaluronic acid.

[0015] In this program, under the action of catalyst, the epoxy group in hyaluronic acid and glycidyl methacrylate structure undergoes ring-opening reaction, alkenyl is introduced in hyaluronic acid structure, obtains alkenylation hyaluronic acid, then under the action of initiator, free radical polymerization reaction occurs in the alkenyl in alkenylation hyaluronic acid structure and the alkenyl in perillaldehyde structure, obtains perillaldehyde modified hyaluronic acid. This kind of perillaldehyde modified hyaluronic acid uses hyaluronic acid as polymer matrix material, can absorb and lock a large amount of water to form a moisturizing layer, makes skin keep moist state, can reduce the damage of external environment to skin, perillaldehyde has excellent antioxidant effect, can effectively remove free radicals, soothe skin, delay skin aging process, perillaldehyde can also suppress the generation of melanin at the same time, and promotes the melanin metabolism generated, reduces the content of melanin in skin, improves dullness, brightens skin color, perillaldehyde is combined with hyaluronic acid, can produce certain protective effect to perillaldehyde by the polymer structure of hyaluronic acid, prevent perillaldehyde effective substance from being lost, so that it can play effect for a long time.

[0016] Furthermore, in step S1, the catalyst is triethylamine.

[0017] Furthermore, in step S2, the initiator is azobisisobutyronitrile.

[0018] Furthermore, the preparation method of the Fritillaria thunbergii polysaccharide microcapsules comprises the following steps:

[0019] (1) adding sodium polystyrene sulfonate to a 0.03-0.05 mol / L calcium nitrate tetrahydrate solution, allowing the mixture to stand for 25-35 minutes, then adding a 0.03-0.05 mol / L sodium carbonate solution, stirring the mixture evenly, allowing the mixture to stand for 30-40 minutes, and collecting the solid after centrifugation. Adding a 1-1.5 mg / ml polyacrylamine hydrochloride solution and a 0.5-0.8 mol / L sodium chloride solution to the solid, stirring the mixture thoroughly for 30-40 minutes, and then centrifuging and washing the mixture to obtain a calcium carbonate template;

[0020] (2) placing konjac glucan and perillaldehyde-modified hyaluronic acid in a sodium chloride solution to prepare a konjac glucan solution and a perillaldehyde-modified hyaluronic acid solution; and then placing chitosan in an acetic acid solution to prepare a chitosan solution;

[0021] (3) adding the konjac glucan solution to the calcium carbonate template, stirring thoroughly for 30-35 minutes, centrifuging and washing, adding the chitosan solution, stirring thoroughly for 30-40 minutes, centrifuging and washing, then adding the perillaldehyde-modified hyaluronic acid solution, stirring thoroughly for 30-35 minutes, centrifuging and washing, adding the complexing agent, removing the calcium carbonate template, and centrifuging and washing to obtain the microcapsule shell;

[0022] (4) Fritillaria thunbergii polysaccharide and glabridin are placed in anhydrous ethanol, mixed thoroughly, and then added into the microcapsule shell. The mixture is mixed at room temperature for 24-48 hours, and then embedded. After the mixture is encapsulated, the product is collected after centrifugation and washing to obtain Fritillaria thunbergii polysaccharide microcapsules.

[0023] Furthermore, in step (2), the concentration of the sodium chloride solution is 0.6-0.8 mol / L; and the mass fraction of the acetic acid is 1-1.5%.

[0024] Furthermore, in step (3), the complexing agent is ethylenediaminetetraacetic acid.

[0025] In this solution, calcium ions in a calcium nitrate tetrahydrate solution and carbonate ions in a sodium carbonate solution combine to form a calcium carbonate precipitate, and a calcium carbonate template is formed under the regulation of sodium polystyrene sulfonate and polyacrylamine hydrochloride; then, a konjac glucan solution, a perillaldehyde-modified hyaluronic acid solution, and a chitosan solution are prepared; and the konjac glucan is coated on the surface of the calcium carbonate template through a layer-by-layer assembly technique, and then chitosan and perillaldehyde-modified hyaluronic acid are coated in sequence; after removing the calcium carbonate template using a chelating agent, a microcapsule shell is formed, and the thunbergii fritillaria polysaccharide and glabridin are embedded in the microcapsule shell to obtain the thunbergii fritillaria polysaccharide microcapsules. The outermost layer of the shell of the Fritillaria thunbergii polysaccharide microcapsule is perillaldehyde-modified hyaluronic acid, which has excellent compatibility with the hyaluronic acid matrix material of the whitening gel, thereby enabling the Fritillaria thunbergii polysaccharide microcapsules to be evenly dispersed in the hyaluronic acid matrix. When the whitening gel is applied to the skin, the hyaluronic acid and the konjac glucan and chitosan in the shell of the Fritillaria thunbergii polysaccharide microcapsules can enhance the skin's moisturizing ability, so that the skin is in a moist and soothing environment. In addition, the Fritillaria thunbergii polysaccharide microcapsules can effectively protect the effective ingredients of the Fritillaria thunbergii polysaccharide from the influence of the external environment, thereby improving the stability and shelf life of the Fritillaria thunbergii polysaccharide and glabridin. When used on the skin, the particle size of the Fritillaria thunbergii polysaccharide microcapsules is small, has good permeability, and can penetrate the skin barrier, so that the Fritillaria thunbergii polysaccharide microcapsules can enhance the whitening and moisturizing effects at a deeper level, effectively exert antioxidant effects, and delay the aging process of the skin. The whitening gel prepared by the present invention can be applied to the skin surface for a long time, is not easy to dry out, and can continue to play a role.

[0026] A method for preparing a whitening gel based on biopolysaccharides comprises the following steps:

[0027] Step 1: placing hyaluronic acid in deionized water, mixing and stirring at a speed of 200-300 r / min for 30-35 minutes to obtain a matrix material;

[0028] Step 2: Add Fritillaria thunbergii polysaccharide microcapsules to the base material, heat to 40-50° C., and stir thoroughly at a speed of 200-250 r / min for 6-8 hours to obtain a whitening gel.

[0029] Beneficial effects of the present invention:

[0030] In this scheme, perillaldehyde-modified hyaluronic acid, konjac glucan and chitosan are prepared as the shell materials of thunbergia thunbergii polysaccharide microcapsules, and thunbergia thunbergii polysaccharide microcapsules are prepared to participate in the preparation process of whitening gel, so that the prepared whitening gel has excellent whitening, moisturizing, antioxidant and anti-aging effects, and the effective ingredients are not easily lost, can be applied to the skin surface for a long time, exert a whitening effect, and delay the aging process of the skin.

[0031] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 The present invention is a flow chart for the preparation of Fritillaria thunbergii polysaccharide microcapsules. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] Example 1

[0036] Preparation of Fritillaria thunbergii polysaccharide

[0037] Weigh 20g of coarse powder of Fritillaria thunbergii medicinal material, add 80ml of deionized water, heat to 60℃ and perform ultrasonic extraction for 30min, filter, concentrate the filtrate, add 20ml of ethanol, stir thoroughly, let stand, centrifuge, and freeze-dry the precipitate to obtain Fritillaria thunbergii polysaccharide.

[0038] Example 2

[0039] Preparation of Perillaldehyde-Modified Hyaluronic Acid

[0040] S1: 3 g of hyaluronic acid and 3.8 g of glycidyl methacrylate were placed in 120 ml of deionized water, stirred thoroughly, and then 0.6 g of triethylamine was added. The mixture was heated to 65°C and stirred for 10 h. The product was collected after vacuum distillation to obtain alkenylated hyaluronic acid.

[0041] S2: 3.6 g of olefinated hyaluronic acid was placed in 130 ml of anhydrous ethanol, and after thorough mixing and stirring, 2.8 g of perillaldehyde and 0.5 g of azobisisobutyronitrile were added, and the temperature was raised to 50° C. for reaction for 6 h. The product was collected after reduced pressure distillation to obtain perillaldehyde-modified hyaluronic acid.

[0042] Example 3

[0043] Preparation of Fritillaria thunbergii polysaccharide microcapsules

[0044] (1) Add 0.3 g of sodium polystyrene sulfonate to 120 ml of 0.03 mol / L calcium nitrate tetrahydrate solution, let it stand for 25 minutes, then add 120 ml of 0.03 mol / L sodium carbonate solution, stir evenly, let it stand for 30 minutes, collect the solid after centrifugation, add 12 ml of 1 mg / ml polyacrylamine hydrochloride solution and 60 ml of 0.5 mol / L sodium chloride solution to the solid, stir thoroughly for 30 minutes, and then centrifuge and wash to obtain a calcium carbonate template;

[0045] (2) 3 g of konjac glucan and 3 g of perillaldehyde-modified hyaluronic acid were placed in 100 ml of 0.6 mol / L sodium chloride solution to prepare konjac glucan solution and perillaldehyde-modified hyaluronic acid solution; 3 g of chitosan was placed in 100 ml of 1% acetic acid solution to prepare chitosan solution;

[0046] (3) 20 ml of konjac glucan solution was added to 5 g of calcium carbonate template, stirred thoroughly for 30 min, and then centrifuged and washed. 20 ml of chitosan solution was added, stirred thoroughly for 30 min, and then centrifuged and washed. 20 ml of perillaldehyde-modified hyaluronic acid solution was added, stirred thoroughly for 30 min, and then centrifuged and washed. 15 ml of ethylenediaminetetraacetic acid was added, and after removing the calcium carbonate template, the microcapsule shell was obtained by centrifugation and washing.

[0047] (4) 5 g of Fritillaria thunbergii polysaccharide and 3 g of glycyrrhizin were placed in 80 ml of anhydrous ethanol, mixed thoroughly, and then 8 g of microcapsule shell was added. The mixture was mixed at room temperature for 24 h and then embedded. After the mixture was centrifuged and washed, the product was collected to obtain Fritillaria thunbergii polysaccharide microcapsules.

[0048] The supernatant during the centrifugal washing was collected, and after removing the solvent by distillation under reduced pressure, the Fritillaria thunbergii polysaccharide was collected and weighed. The embedding efficiency was calculated according to the following formula: embedding efficiency = (total mass of Fritillaria thunbergii polysaccharide and glabridin - mass of Fritillaria thunbergii polysaccharide and glabridin in the supernatant) × 100% / total mass of Fritillaria thunbergii polysaccharide and glabridin; the embedding efficiency of the Fritillaria thunbergii polysaccharide microcapsules was calculated to be 64.5%.

[0049] Depend on Figure 1 It can be seen that the preparation process of thunbergii polysaccharide microcapsules is that calcium ions in a calcium nitrate tetrahydrate solution and carbonate ions in a sodium carbonate solution are combined with each other to form a calcium carbonate precipitate, and a calcium carbonate template is formed under the regulation of polystyrene sulfonate sodium salt and polyacrylamine hydrochloride; then konjac glucan solution, chitosan solution and perillaldehyde-modified hyaluronic acid solution are added in sequence, konjac glucan is coated on the surface of the calcium carbonate template through a layer-by-layer assembly technology, and then chitosan and perillaldehyde-modified hyaluronic acid are coated in sequence, and after removing the calcium carbonate template with a chelating agent, a microcapsule shell is formed, and thunbergii polysaccharide and glycyrrhizin are embedded in the microcapsule shell to obtain thunbergii polysaccharide microcapsules. By embedding the thunbergii polysaccharide and glycyrrhizin, the thunbergii polysaccharide can be effectively protected so that it can play a more excellent and long-lasting whitening, moisturizing and anti-aging effect.

[0050] Example 4

[0051] Preparation of whitening gel

[0052] Step 1: 50 parts of hyaluronic acid were added to 100 parts of deionized water, and the mixture was stirred at a speed of 200 r / min for 30 minutes to obtain a matrix material;

[0053] Step 2: add 15 parts of Fritillaria thunbergii polysaccharide microcapsules to the base material, heat to 40° C., and stir thoroughly at a speed of 200 r / min for 6 hours to obtain a whitening gel.

[0054] Example 5

[0055] Preparation of whitening gel

[0056] Step 1: 65 parts of hyaluronic acid were added to 125 parts of deionized water, and the mixture was stirred at a speed of 250 r / min for 33 minutes to obtain a matrix material;

[0057] Step 2: add 18 parts of Fritillaria thunbergii polysaccharide microcapsules to the base material, heat to 45° C., and stir thoroughly at a speed of 220 r / min for 7 hours to obtain a whitening gel.

[0058] Example 6

[0059] Preparation of whitening gel

[0060] Step 1: 80 parts of hyaluronic acid were added to 150 parts of deionized water, and the mixture was stirred at a speed of 300 r / min for 35 minutes to obtain a matrix material;

[0061] Step 2: add 20 parts of Fritillaria thunbergii polysaccharide microcapsules to the base material, heat to 50° C., and stir thoroughly at a speed of 250 r / min for 8 hours to obtain a whitening gel.

[0062] Comparative Example 1

[0063] Preparation of whitening gel

[0064] Step 1: 65 parts of hyaluronic acid were added to 125 parts of deionized water, and the mixture was stirred at a speed of 250 r / min for 33 minutes to obtain a matrix material;

[0065] Step 2: Add 18 parts of perillaldehyde-modified hyaluronic acid to the base material, raise the temperature to 45° C., and stir thoroughly at a speed of 220 r / min for 7 hours to obtain a whitening gel.

[0066] Comparative Example 2

[0067] Step 1: 65 parts of hyaluronic acid were added to 125 parts of deionized water, and the mixture was stirred at a speed of 250 r / min for 33 minutes to obtain a matrix material;

[0068] Step 2: add 18 parts of Fritillaria thunbergii polysaccharide and glabridin in a mass ratio of 5:3 to the base material, heat to 45° C., and stir thoroughly at a speed of 220 r / min for 7 hours to obtain a whitening gel.

[0069] Performance testing

[0070] ① The whitening gels prepared in Examples 4 to 6 and Comparative Examples 1 to 2 were used as samples, and the free radical scavenging rate and tyrosinase activity of the samples were tested using a free radical scavenging kit and a tyrosinase kit. A higher free radical scavenging rate indicates a better free radical scavenging effect of the sample, and a stronger antioxidant and anti-aging ability of the sample; a lower tyrosinase activity indicates a better tyrosinase inhibitory effect and a better whitening effect. The specific test results are shown in Table 1 below.

[0071] Table 1:

[0072]

[0073]

[0074] As can be seen from Table 1, the whitening gels prepared in Examples 4 to 6 have high free radical scavenging rates and low tyrosinase activity, and have excellent antioxidant, anti-aging and whitening effects. In the sample prepared in Comparative Example 1, no thunbergii polysaccharide microcapsules were added, and perillaldehyde-modified hyaluronic acid was directly added; in the sample prepared in Comparative Example 2, no thunbergii polysaccharide microcapsules were added, and thunbergii polysaccharide and glabridin were directly added; the samples prepared in the comparative examples and comparative example 2 both have certain antioxidant, anti-aging and whitening effects, but the effects are not as good as those of the samples prepared in the examples.

[0075] ② Fifty men and fifty women aged 20-45 were randomly selected and divided into five groups, with an equal number of men and women in each group. After cleansing their faces, they sat quietly for 15 minutes. After the facial skin had reached equilibrium with the external environment, a 3 cm diameter circle was drawn as the test area. 8 g of the whitening gel prepared in Examples 4-6 and Comparative Examples 1-2 was used as a sample and applied to the test area. One hour later, a skin moisture test was performed on the test area using an MC760 skin tester before and after application. The results were averaged. The specific test data are shown in Table 2 below.

[0076] Table 2:

[0077]

[0078]

[0079] As can be seen from Table 2 above, the whitening gels prepared in Examples 4 to 6, Comparative Examples 1 and 2 all have excellent moisturizing effects. Although the whitening gels prepared in Comparative Examples 1 and 2 do not contain thunbergia thunbergii polysaccharide microcapsules, the addition of perillaldehyde-modified hyaluronic acid or thunbergia thunbergii polysaccharide and glabridin can enhance the moisturizing ability of the whitening gel, enabling it to have good moisturizing ability, but the final moisturizing effect is not as good as that of the samples prepared in the examples.

[0080] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0081] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A whitening gel based on biopolysaccharide, characterized in that: The invention comprises the following raw materials in parts by weight: 50-80 parts of hyaluronic acid, 100-150 parts of deionized water, and 15-20 parts of thunbergii polysaccharide microcapsules; the thunbergii polysaccharide microcapsules are prepared by using konjac glucan, chitosan, and perillaldehyde-modified hyaluronic acid as a shell layer, and embedding thunbergii polysaccharide and glabridin as a core material; the perillaldehyde-modified hyaluronic acid is prepared by reacting olefinated hyaluronic acid with perillaldehyde under the action of an initiator; and the olefinated hyaluronic acid is prepared by reacting hyaluronic acid with glycidyl methacrylate under the action of a catalyst.

2. The whitening gel based on biopolysaccharide according to claim 1, characterized in that: The preparation method of the Fritillaria thunbergii polysaccharide comprises the following steps: Weigh the coarse powder of Fritillaria thunbergii medicinal material, add deionized water to mix, perform ultrasonic extraction, filter, concentrate the filtrate, add ethanol, stir thoroughly, let stand, centrifuge, and freeze-dry the precipitate to obtain Fritillaria thunbergii polysaccharide.

3. The whitening gel based on biopolysaccharide according to claim 2, characterized in that: The temperature of the ultrasonic extraction is 60-65° C., and the time is 30-40 minutes.

4. The whitening gel based on biopolysaccharide according to claim 1, characterized in that: The preparation method of the perillaldehyde-modified hyaluronic acid comprises the following steps: S1: Place hyaluronic acid and glycidyl methacrylate in deionized water, stir thoroughly, add a catalyst, heat to 65-75°C, stir for 10-15 hours, and collect the product after reduced pressure distillation to obtain olefinated hyaluronic acid; S2: Place the olefinated hyaluronic acid in anhydrous ethanol, mix and stir thoroughly, add perillaldehyde and initiator, raise the temperature to 50-55°C and react for 6-8 hours, and collect the product after reduced pressure distillation to obtain perillaldehyde-modified hyaluronic acid.

5. The whitening gel based on biopolysaccharide according to claim 4, characterized in that: In step S1, the catalyst is triethylamine.

6. The whitening gel based on biopolysaccharide according to claim 4, characterized in that: In step S2, the initiator is azobisisobutyronitrile.

7. The whitening gel based on biopolysaccharide according to claim 1, characterized in that: The preparation method of the Fritillaria thunbergii polysaccharide microcapsules comprises the following steps: (1) adding sodium polystyrene sulfonate to a 0.03-0.05 mol / L calcium nitrate tetrahydrate solution, allowing the mixture to stand for 25-35 minutes, then adding a 0.03-0.05 mol / L sodium carbonate solution, stirring the mixture evenly, allowing the mixture to stand for 30-40 minutes, and collecting the solid after centrifugation. Adding a 1-1.5 mg / ml polyacrylamine hydrochloride solution and a 0.5-0.8 mol / L sodium chloride solution to the solid, stirring the mixture thoroughly for 30-40 minutes, and then centrifuging and washing the mixture to obtain a calcium carbonate template; (2) placing konjac glucan and perillaldehyde-modified hyaluronic acid in a sodium chloride solution to prepare a konjac glucan solution and a perillaldehyde-modified hyaluronic acid solution; and then placing chitosan in an acetic acid solution to prepare a chitosan solution; (3) adding the konjac glucan solution to the calcium carbonate template, stirring thoroughly for 30-35 minutes, centrifuging and washing, adding the chitosan solution, stirring thoroughly for 30-40 minutes, centrifuging and washing, then adding the perillaldehyde-modified hyaluronic acid solution, stirring thoroughly for 30-35 minutes, centrifuging and washing, adding the complexing agent, removing the calcium carbonate template, and centrifuging and washing to obtain the microcapsule shell; (4) Fritillaria thunbergii polysaccharide and glabridin are placed in anhydrous ethanol, mixed thoroughly, and then added into the microcapsule shell. The mixture is mixed at room temperature for 24-48 hours, and then embedded. After the mixture is encapsulated, the product is collected after centrifugation and washing to obtain Fritillaria thunbergii polysaccharide microcapsules.

8. The whitening gel based on biopolysaccharide according to claim 7, characterized in that: In step (2), the concentration of the sodium chloride solution is 0.6-0.8 mol / L; the mass fraction of the acetic acid is 1-1.5%.

9. The whitening gel based on biopolysaccharide according to claim 7, characterized in that: In step (3), the complexing agent is ethylenediaminetetraacetic acid.

10. The method for preparing a whitening gel based on biopolysaccharide according to claim 1, characterized in that: The following steps are involved: Step 1: placing hyaluronic acid in deionized water, mixing and stirring at a speed of 200-300 r / min for 30-35 minutes to obtain a matrix material; Step 2: Add Fritillaria thunbergii polysaccharide microcapsules to the base material, heat to 40-50° C., and stir thoroughly at a speed of 200-250 r / min for 6-8 hours to obtain a whitening gel.

Images