CN108354864B - A kind of preparation method of emulsion with whitening and moisturizing effect - Google Patents

Abstract

The invention provides a preparation method of an emulsion with whitening and moisturizing effects, which comprises the following steps: (1) weighing hydrogenated soybean oil, and heating to 75-85 ℃ to obtain a liquid oil phase I; (2) weighing arbutin, ascorbyl glucoside and nicotinamide in proportion, and mixing the three substances to obtain a composite whitening active substance; (3) adding the composite whitening active substance into the liquid oil phase I according to a certain proportion, and uniformly mixing to obtain a liquid oil phase II; (4) weighing the algal polysaccharide enzymolysis product, phospholipid and distilled water according to a proportion, heating to 75-85 ℃, and uniformly mixing to obtain a liquid water phase; (5) weighing the liquid oil phase II, the liquid water phase and the tea polyphenol according to the proportion, mixing and stirring uniformly to obtain a mixed solution, and homogenizing the mixed solution at high pressure to obtain the nano emulsion; and cooling the obtained nano emulsion to room temperature, and adding a proper amount of preservative to obtain the emulsion with the whitening and moisturizing effects. The emulsion prepared by the invention has whitening and moisturizing effects and good stability.

Description

A kind of preparation method of emulsion with whitening and moisturizing effect

(1) Technical field

The invention belongs to the technical field of cosmetics, and in particular relates to a preparation method of an emulsion with whitening and moisturizing effects.

(2) Technical background

Whitening has always been paid close attention by people, and whitening skin care products have always been respected and pursued by the majority of women. Differences in human skin color usually depend on factors such as the content and distribution of epidermal melanin, the structure of dermal collagen fibers, and the thickness and water content of the stratum corneum.

At present, most whitening skin care products on the market generally have the problem of a single whitening mechanism: the products are only aimed at the formation and transfer mechanism of melanin, from inhibiting tyrosinase activity, reducing the generated melanin and inhibiting the transfer of melanin. Step by step to carry out whitening formula design, can not achieve full effect whitening. And the product stability is poor, because the whitening agent is easily oxidized and deactivated, or decomposed under the light, if it is directly added to the formula, it will easily lead to the product discoloration, odor, and even problems such as stratification and thickening of the paste.

Patent CN 107374988 A discloses a preparation method of nonionic vesicles with whitening effect. The processing method uses traditional whitening agent, hydroxyphenoxypropionic acid, phloretin, hydroxytyrosol, extract of Rhizoma chinensis root and polyhydric alcohol as whitening components, and uses glycerol oleate citric acid ester, spermaceti hard Aliphatic glucoside and polyglycerol-3 methyl glucodistearate are nonionic surfactant premixes, and after homogenization, a nonionic vesicle with whitening effect is obtained. However, this method uses non-ionic surfactants and cannot effectively encapsulate all the active ingredients.

Patent CN 103690380 A discloses a method for preparing a whitening nanoparticle emulsion with a solid-phase core. The method uses paeonol, daisy flower extract, black tea seed oil, and mandelic acid as whitening agents, and glycerin hard Fatty acid ester, cetearyl ether-20 and cetearyl ether-12 are emulsifiers, and after homogenization and cooling, a whitening nanoparticle emulsion with a solid core is obtained. Since the emulsion prepared by this method is a solid core, it will have a grainy feeling when used, giving a feeling that the active ingredient is not completely dissolved.

(3) Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method of an emulsion with whitening and moisturizing effect and good stability.

The technical scheme of the present invention is specifically described below:

The invention provides a preparation method of an emulsion with whitening and moisturizing effect, comprising the following steps:

(1) Weighing hydrogenated soybean oil, heating to 75-85 ° C to obtain liquid oil phase I;

(2) weigh arbutin, ascorbic acid glucoside, nicotinamide in a ratio of 2-4: 3-6: 1 by mass ratio, and mix the above-mentioned three substances to obtain a composite whitening active substance;

(3) adding the composite whitening active substance to the liquid oil phase I obtained in step (1), and mixing uniformly to obtain a liquid oil phase II; wherein the mass ratio of the composite whitening active substance to the liquid oil phase I is 0.15 to 0.30: 1;

(4) Weigh seaweed polysaccharide enzymolysis product, phospholipid and distilled water in a ratio of 0.08～0.2:0.05～0.1:1 by mass, heat to 75～85°C, and mix well to obtain a liquid water phase;

(5) weigh the liquid oil phase II obtained in step (3), the liquid water phase obtained in step (4), and tea polyphenols in a mass ratio of 15 to 25: 120 to 150: 1, mix and stir to obtain a mixed solution, and mix The liquid is subjected to high-pressure homogenization in a high-pressure homogenizer to obtain a nanoemulsion, ensuring that the temperature of the mixed solution at the outlet of the high-pressure homogenizer does not exceed 90 °C; the obtained nanoemulsion is cooled to room temperature, and an appropriate amount of preservative is added to obtain an emulsion with whitening and moisturizing effects. .

In the present invention, the enzymatic hydrolysis product of seaweed polysaccharide is prepared by the following method: seaweed polysaccharide is obtained by water extraction and alcohol precipitation, and seaweed polysaccharide is obtained by enzymatic hydrolysis of seaweed polysaccharide by glucanase. The specific operation steps are as follows:

(a) Extraction method of seaweed polysaccharide: wash seaweed, dry, pulverize to obtain algal powder; take algal powder, add 95% ethanol solution to soak and degrease, and let stand overnight; take degreased algal powder, press 1kg:8～12L (preferably 1kg:10L), add distilled water in the ratio of material to liquid, 80～100℃ (preferably 95℃) water bath for 1～3h (preferably 2h), after hot water extraction, cool and let stand for 0.5～1.5h (preferably 1h) , freeze and centrifuge, take the supernatant, i.e. the crude polysaccharide extract, and concentrate it to a certain volume by rotary evaporation, add ethanol solution (preferably ethanol solution with a volume fraction of 95%) until the final ethanol volume fraction is 30%, and let stand overnight; the sample solution is frozen Centrifuge, take the precipitate, add an appropriate amount of distilled water to completely dissolve the precipitate, evaporate under reduced pressure and completely evaporate the residual alcohol, concentrate, and freeze-dry to obtain the seaweed polysaccharide;

(b) Enzymatic hydrolysis method of seaweed polysaccharide: take seaweed polysaccharide, prepare a solution of seaweed polysaccharide with a mass concentration of 2-7% (preferably 5%) with distilled water, and then add dextran having a mass of 2-5% (preferably 3.5%) of seaweed polysaccharide mass Carbohydrase, react for 1-3h (preferably 2h) under the conditions of pH=4.8 and temperature 48°C, stand to cool, evaporate under reduced pressure and concentrate to a certain concentration for later use; select a dialysis bag with a pore size of 500Da, put it in The concentrated liquid is dialyzed under running water for 12-36 h (preferably 24 h), and left to stand overnight; repeated several times, the dialysate is concentrated under reduced pressure, and freeze-dried to obtain the enzymatic hydrolysis product of seaweed polysaccharide.

In step (5) of the present invention, the preservatives can be selected from commonly used preservatives in the field, such as benzyl alcohol, imidazolidinyl urea, methylparaben, etc. In the present invention, preferably benzyl alcohol, imidazolidinyl urea, paraben The mixture of methyl esters is used as a preservative, and the added mass of the preservative is 0.3-0.4% of the mass of the nanoemulsion, and the most preferably 0.2% benzyl alcohol, 0.1% imidazolidinyl urea and 0.05% methylparaben are used as the preservative.

In step (5) of the present invention, the high-pressure homogenization conditions are: under the conditions of 70-150MPa pressure and 75-90°C temperature, circulating homogenization through the high-pressure homogenizer for 5-15 times, and using a cooling device at the outlet of the high-pressure homogenizer , to ensure that the temperature of the mixed liquid at the outlet of the high-pressure homogenizer does not exceed 90 °C, and the nanoemulsion is obtained after the homogenization is completed.

The advantages of the present invention and the beneficial effects produced:

(1) In the present invention, seaweed polysaccharide is mixed with phospholipid after enzymolysis treatment to form a compound emulsifier, and the compound emulsifier has better emulsifying and moisturizing properties.

Specifically, seaweed polysaccharide has excellent colloidal properties and also has certain moisturizing properties. After the seaweed polysaccharide is hydrolyzed by glucanase, the cleavage of the glycosidic bond reduces the molecular weight of the polysaccharide and the viscosity of the solution, and also exposes the hydrophobic region and active site of the seaweed polysaccharide, which makes the emulsifying activity and resistance of the seaweed polysaccharide more effective. The oxidative activity was improved. Phospholipid is a natural amphoteric emulsifier with good moisturizing and emulsifying ability, and the formed emulsion has good stability. The enzymatic hydrolysis product of seaweed polysaccharide is mixed with phospholipids to obtain a compound emulsifier. The formed emulsion not only has macromolecular polysaccharides as interface stabilizers, but also small molecular phospholipids are distributed among the macromolecules, which can effectively reduce the surface activation energy. . The hydrophilic group on the hydrolyzed product of seaweed polysaccharide is different from the hydrophilic group of phospholipid, which can stabilize different active ingredients. The combination of the two can produce complementary emulsifying advantages and good moisturizing effect.

(2) In the present invention, arbutin, ascorbic acid glucoside and nicotinamide are mixed in a certain proportion as an oil phase, which has a whitening effect.

Specifically, arbutin is a natural active substance derived from green plants. It can quickly penetrate into the skin. It can effectively inhibit the activity of tyrosinase in the skin without affecting the concentration of cell proliferation and block the production of melanin. Formation, through its direct combination with tyrosinase, accelerates the decomposition and excretion of melanin, thereby reducing skin pigmentation, removing pigmentation and freckles, and does not produce toxic, irritating, sensitizing and other side effects to melanocytes, and also It has bactericidal and anti-inflammatory effects. Reduced glutathione is a tripeptide containing γ-amide bond and sulfhydryl group. It is composed of glutamic acid, cysteine and glycine. It has antioxidant effects and integrated detoxification. Most of them are glycerides, which can correct the imbalance of acetylcholine and cholinesterase, play an anti-allergic effect, prevent skin aging and pigmentation, reduce the formation of melanin, and make the skin shiny. Niacinamide is a derivative of vitamin B3, which participates in the process of melanin transport and can accelerate the movement rate of melanosomes in melanocytes, inhibit the transport of formed melanin to epidermal keratinocytes, thereby reducing melanin in the skin. The three have three different mechanisms to achieve the whitening effect from inhibiting the activity of tyrosinase, reducing the intermediates in the process of melanin formation, and inhibiting the transport of the formed melanin to the epidermal keratinocytes.

(3) In the present invention, adding tea polyphenols into the emulsion can not only increase the whitening effect of the emulsion, but also play a role in stabilizing the emulsion.

Specifically, from a cosmetic point of view, in addition to achieving the whitening effect from the above three mechanisms, currently, endothelin antagonists are also a new whitening strategy. Tea polyphenol is an endothelin antagonist. Its mechanism of action is different from the inhibition of tyrosinase activity. It achieves the effect of whitening and freckle removal by inhibiting the regulation of endothelin on the proliferation of melanocytes. Under the action of tea polyphenols, endothelin cannot connect with receptors on melanocortin cells, so no additional melanin will be formed. In addition, tea polyphenols can interact with seaweed polysaccharide hydrolysis products through hydrogen bonding, electrostatic interaction, etc. The addition of tea polyphenols can change the secondary structure of seaweed polysaccharide hydrolysis products, thereby improving the emulsifying properties of seaweed polysaccharide hydrolysis products. .

(4) Specific implementation methods

The present invention is further described below in conjunction with specific embodiment, but the protection scope of the present invention is not limited to this:

Example 1: Preparation of seaweed polysaccharide enzymatic hydrolysis product

1. Extraction method of seaweed polysaccharide: Wash the seaweed, control the water, dry in an oven at 60°C, and pulverize. Take 1kg of algal powder, add 2L of 95% ethanol solution to soak and degrease, and let stand overnight. Take the degreased algal powder, add distilled water at a ratio of 1kg:10L of material to liquid, and take a water bath at 95°C for 2h. After the hot water extraction was completed, it was left to cool and stand for 1 h, and then refrigerated and centrifuged for 10 min (rotation speed 10000 rpm, temperature 4 °C). The supernatant, ie the crude polysaccharide extract, was concentrated to 2 L by rotary evaporation, and 95% ethanol solution was added until the final ethanol volume fraction was 30%, and left standing overnight. The sample solution was refrigerated and centrifuged for 10 min (rotation speed 10000 rpm, temperature 4 °C), the precipitate was taken, a small amount of distilled water was added to completely dissolve the precipitate, evaporated under reduced pressure and the residual alcohol was completely evaporated, and concentrated to 20 mL, and freeze-dried to obtain seaweed polysaccharide.

2. Enzymatic hydrolysis method of seaweed polysaccharide: take seaweed polysaccharide, prepare 5% seaweed polysaccharide solution with distilled water, and then add glucanase (purchased from Ningxia Xiasheng Industrial Group Co., Ltd.) with a mass of 3.5% of seaweed polysaccharide mass, at pH= 4.8. The reaction was carried out under the condition of temperature of 48°C for 2h, left to cool, evaporated under reduced pressure and concentrated to 4% for use. A dialysis bag with a pore size of 500 Da was selected, and 20 mL of the enzymatic hydrolysis reaction solution containing 4% soluble solids was put into running water for dialysis for 24 hours, and left to stand overnight. Repeated for several times, the dialysate was concentrated under reduced pressure to 10 mL, and freeze-dried to obtain an enzymatic hydrolysis product of seaweed polysaccharide.

Example 2:

(1) 20 g of hydrogenated soybean oil (purchased from Wuhan Hezhong Biochemical Manufacturing Co., Ltd.) was weighed, heated to 85° C. to obtain liquid oil phase I;

(2) 4g of arbutin (purchased from Xi'an Lutian Biotechnology Co., Ltd.), 6g of ascorbyl glucoside (purchased from Xi'an Wanfang Biotechnology Co., Ltd.), nicotinamide were weighed in a ratio of 4:6:1 by mass (purchased from Henan Datang Chemical Co., Ltd.) 1g, the above-mentioned three kinds of substances are mixed to obtain a composite whitening active substance;

(3) composite whitening active substance by mass ratio: liquid oil phase I=0.30: 1, take by weighing composite whitening active substance 6g and add in the liquid oil phase I of step (1) gained, mix homogeneously, obtain liquid oil phase II;

(4) weigh 30g of seaweed polysaccharide enzymolysis product, 15g of phospholipids and 150g of distilled water in a ratio of 0.2:0.1:1 by mass, heat to 75-85°C, and mix to obtain a liquid water phase;

(5) weigh 25 g of liquid oil phase II obtained in step (3), 150 g of liquid water phase obtained in step (4) and 1 g of tea polyphenols in a mass ratio of 25: 150: 1, and weigh the liquid oil phase II, liquid water The phase and tea polyphenols are mixed and stirred evenly to obtain a mixed liquid. The mixed liquid is circulated and homogenized for 5 times through a high-pressure homogenizer under the conditions of 150MPa pressure and 90 °C temperature, and a cooling device is used at the outlet of the high-pressure homogenizer to ensure high-pressure homogenization. The temperature of the mixed liquid at the outlet of the machine does not exceed 90 °C, and the nanoemulsion is obtained after the homogenization is completed; the obtained nanoemulsion is cooled to room temperature, and 0.2% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% are added based on the emulsion quality as 100%. Methylparaben is used as a preservative to obtain a whitening and moisturizing lotion.

Example 3:

(1) 15 g of hydrogenated soybean oil (purchased from Wuhan Hezhong Biochemical Manufacturing Co., Ltd.) was weighed, heated to 85° C. to obtain liquid oil phase I;

(2) 1 g of arbutin (purchased from Xi'an Lvtian Biotechnology Co., Ltd.), 1.5 g of ascorbyl glucoside (purchased from Xi'an Wanfang Biotechnology Co., Ltd.), Amide (purchased from Henan Datang Chemical Co., Ltd.) 0.5g, the above three substances were mixed to obtain a composite whitening active substance;

(3) by mass ratio composite whitening active substance: liquid oil phase I=0.15: 1 take by weighing composite whitening active substance 2.25g and add in the liquid oil phase I of step (1) gained, mix homogeneously, obtain liquid oil phase II;

(4) weigh 12g of seaweed polysaccharide enzymolysis product, 7.5g of phospholipid and 150g of distilled water in a ratio of 0.08:0.05:1 by mass, heat to 75～85°C, and mix to obtain a liquid water phase;

(5) weigh 15 g of liquid oil phase II obtained in step (3), 120 g of liquid water phase obtained in step (4) and 1 g of tea polyphenols in a mass ratio of 15: 120: 1, and weigh the liquid oil phase II, liquid water The phase and tea polyphenols are mixed and stirred evenly to obtain a mixed liquid. The mixed liquid is circulated and homogenized for 5 times through a high-pressure homogenizer under the conditions of 150MPa pressure and 90 °C temperature, and a cooling device is used at the outlet of the high-pressure homogenizer to ensure high-pressure homogenization. The temperature of the mixed liquid at the outlet of the machine does not exceed 90 °C, and the nanoemulsion is obtained after the homogenization is completed; the obtained nanoemulsion is cooled to room temperature, and 0.2% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% are added based on the emulsion quality as 100%. Methylparaben is used as a preservative to obtain a whitening and moisturizing lotion.

Example 4:

(1) 20 g of hydrogenated soybean oil (purchased from Wuhan Hezhong Biochemical Manufacturing Co., Ltd.) was weighed, heated to 85° C. to obtain liquid oil phase I

(2) 1.6 g of arbutin (purchased from Xi'an Lutian Biotechnology Co., Ltd.), 4.8 g of ascorbic acid glucoside (purchased from Xi'an Wanfang Biotechnology Co., Ltd.), Niacinamide (purchased from Henan Datang Chemical Co., Ltd.) 0.8g, the above three substances were mixed to obtain a composite whitening active substance;

(3) by mass ratio composite whitening active substance: liquid oil phase I=0.2: 1 take by weighing composite whitening active substance 4g and add in the liquid oil phase I of step (1) gained, mix homogeneously, obtain liquid oil phase II;

(4) weigh 12g of seaweed polysaccharide enzymolysis product, 15g of phospholipids and 150g of distilled water in a ratio of 0.08:0.1:1 by mass, heat to 75～85°C, and mix to obtain a liquid water phase;

(5) weigh 25 g of liquid oil phase II obtained in step (3), 140 g of liquid water phase obtained in step (4) and 1 g of tea polyphenols in a mass ratio of 25: 140: 1, and weigh the liquid oil phase II, liquid water The phase and tea polyphenols are mixed and stirred evenly to obtain a mixed liquid. The mixed liquid is circulated and homogenized for 5 times through a high-pressure homogenizer under the conditions of 150MPa pressure and 90 °C temperature, and a cooling device is used at the outlet of the high-pressure homogenizer to ensure high-pressure homogenization. The temperature of the mixed liquid at the outlet of the machine does not exceed 90 °C, and the nanoemulsion is obtained after the homogenization is completed; the obtained nanoemulsion is cooled to room temperature, and 0.2% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% benzyl alcohol, 0.1% imidazolidinyl urea, 0.05% are added based on the emulsion quality as 100%. Methylparaben is used as a preservative to obtain a whitening and moisturizing lotion.

Example 5: Emulsion performance test:

(1) Experimental method for determination of tyrosinase inhibition rate:

Add sample system: prepare pH=6.8 phosphate buffer solution (PBS); 200U/mL tyrosinase phosphate buffer solution (operated and stored in ice-water bath); 2.5mmol/L L-tyrosine Acid buffer solution; take 1.5 mL of L-tyrosine buffer solution, 1.5 mL of PBS solution, and 1 mL of the emulsion with whitening and moisturizing effect prepared in the above example, mix them, and keep them in a 37°C water bath for 10 min, and add 1 mL of tyrosinase phosphate buffer. The solution was reacted for 10 min, and the absorbance was measured at 475 nm.

System without sample added: Phosphate buffer solution (PBS) with pH=6.8; tyrosinase phosphate buffer solution with concentration of 200U/mL (operated and stored in ice-water bath); L-phenol with concentration of 2.5mmol/L acid buffer solution; take 1.5mL L-tyrosine buffer solution, 1.5mL PBS solution, 1mL deionized water, mix, incubate in 37°C water bath for 10min, add 1mL tyrosinase phosphate buffer solution, react for 10min, at 475nm Absorbance value was measured.

The inhibition rate of tyrosinase was calculated as follows:

Inhibition rate=(A-B)/A×100%

Among them, A is the absorbance value of the system without adding the sample, and B is the absorbance value of the system after adding the sample.

The test results are shown in Table 1.

(2) Stability test index:

a. Heat resistance. After the whitening and moisturizing lotion was stored at 40°C for 15 days, it was visually observed whether there was a significant difference between the properties and color before the test, whether there was delamination and oil slick.

b. Cold resistance. After the whitening and moisturizing lotion was stored at 0°C for 15 days, it was visually observed whether there was a significant difference between the properties and color before the test, whether there was delamination or oil slick.

c. Hot and cold cycle. After the whitening and moisturizing lotion was tested by alternating hot and cold cycles (15 days at 40°C, then 15 days at 0°C, and 3 cycles of treatment), it was visually observed whether it was significantly different from the properties and colors before the test. Layer and oil slick phenomenon, if there is no obvious difference, it indicates that the emulsion product has better cold resistance.

The test results are shown in Table 1.

(3) Moisturizing performance test: After smearing the lotion on the hands for 15 minutes, use a skin moisture tester (Haiyue skin tester) to measure the change in skin moisture content within 30 minutes, pay attention to the same position on the hands to measure, and measure 3 times, take the average value. Before applying the whitening and moisturizing lotion, the moisture rate of the skin at the same position on the hand remained basically at 33.6% after 30 minutes.

Table 1

Claims (3)

1. A preparation method of an emulsion with whitening and moisturizing effects comprises the following steps:

(1) weighing hydrogenated soybean oil, and heating to 75-85 ℃ to obtain a liquid oil phase I;

(2) weighing arbutin, ascorbyl glucoside and nicotinamide according to the mass ratio of 2-4: 3-6: 1, and mixing the three substances to obtain a composite whitening active substance;

(3) adding the composite whitening active substance into the liquid oil phase I obtained in the step (1), and uniformly mixing to obtain a liquid oil phase II; wherein the mass ratio of the composite whitening active substance to the liquid oil phase I is 0.15-0.30: 1;

(4) according to the mass ratio of 0.08-0.2: weighing the algal polysaccharide enzymolysis product, phospholipid and distilled water according to the ratio of 0.05-0.1: 1, heating to 75-85 ℃, and uniformly mixing to obtain a liquid water phase;

(5) according to the mass ratio of 15-25: 120-150: 1, weighing the liquid oil phase II obtained in the step (3), the liquid water phase obtained in the step (4) and tea polyphenol, mixing and stirring uniformly to obtain a mixed solution, carrying out high-pressure homogenization on the mixed solution in a high-pressure homogenizer to obtain nano emulsion, and ensuring that the temperature of the mixed solution at an outlet section of the high-pressure homogenizer is not more than 90 ℃; cooling the obtained nano emulsion to room temperature, and adding a proper amount of preservative to obtain the emulsion with whitening and moisturizing effects;

the preparation method of the algal polysaccharide enzymolysis product comprises the following specific operation steps:

(a) the algal polysaccharide extraction method comprises the steps of cleaning algae, drying and crushing to obtain algal powder, soaking and degreasing the algal powder in 95% ethanol solution by volume, standing overnight, adding distilled water into the degreased algal powder according to the material-liquid ratio of 1kg to 8-12L, carrying out water bath at 80-100 ℃ for 1-3 h, cooling and standing for 0.5-1.5 h after hot water extraction is finished, carrying out refrigerated centrifugation, taking supernate, namely polysaccharide crude extract, carrying out rotary evaporation and concentration to a certain volume, adding the ethanol solution until the final ethanol volume fraction is 30%, standing overnight, carrying out refrigerated centrifugation on sample liquid, taking precipitate, adding a proper amount of distilled water to completely dissolve the precipitate, carrying out reduced pressure evaporation, completely evaporating residual ethanol, concentrating, and carrying out freeze drying to obtain algal polysaccharide;

(b) the algal polysaccharide enzymolysis method comprises the following steps: preparing a seaweed polysaccharide solution with the mass concentration of 2-7% by using distilled water, adding glucanase with the mass concentration of 2-5% by mass of the seaweed polysaccharide, reacting for 1-3 h under the conditions that the pH value is 4.8 and the temperature is 48 ℃, standing, cooling, and carrying out reduced pressure evaporation and concentration to a certain concentration for later use; selecting a dialysis bag with the aperture size of 500Da, filling the dialysis bag into concentrated liquid flow for dialysis for 12-36 h, and standing overnight; repeating the steps for multiple times, decompressing and concentrating the dialyzate, and freeze-drying to obtain the algal polysaccharide enzymolysis product.

2. The method of claim 1, wherein: in the step (5), the preservative is a mixture of benzyl alcohol, imidazolidinyl urea and methyl paraben, and the adding mass of the preservative is 0.3-0.4% of the mass of the nano emulsion.

3. The method of claim 1, wherein: in the step (5), the high-pressure homogenizing condition is as follows: and circularly homogenizing for 5-15 times by a high-pressure homogenizer under the conditions of 70-150 MPa pressure and 75-90 ℃, using a cooling device at the outlet of the high-pressure homogenizer to ensure that the temperature of the mixed liquid at the outlet section of the high-pressure homogenizer is not more than 90 ℃, and obtaining the nano emulsion after homogenization.