Xylitol-based glucoside polysaccharide humectant and preparation method thereof

Abstract

The invention relates to a xylitol-based glucoside polysaccharide humectant and a preparation method thereof. Xylitol and glucose are used as raw materials, glycosylation and dehydration are completed under p-toluenesulfonic acid catalysis and vacuum conditions, and then alkalization and hydrogen peroxide decoloration are performed to obtain a target product. The obtained product has m / z 313.108 + / -0.005, m / z 475.161 + / -0.005 and 637.214 + / -0.006 characteristic peaks in a high-resolution mass spectrum, and liquid phase evaporative light scattering detection shows that the proportions of the polymerization degrees 1, 2 and 3 are 30%-55%, 25%-45% and 10%-25%. The color difference delta E * of the raw material liquid is less than or equal to 2.0 after accelerated storage at 45 DEG C for 28 days, and the raw material liquid has good stability; when being used as a cosmetic additive, 0.1%-5% of the composition can improve the water content of cuticle and reduce percutaneous water loss, and has both mildness and formula compatibility.

Description

Technical Field

[0001] This invention relates to the technical field of cosmetic raw material synthesis, and in particular to a xylitol glucoside polysaccharide moisturizer and its preparation method. Background Technology

[0002] As consumers increasingly value the "efficacy, safety, and gentleness" of skincare products, natural polysaccharide moisturizers have become a research hotspot due to their excellent skin compatibility and sustainability. Existing moisturizers such as glycerin, propylene glycol, and sodium hyaluronate, while possessing moisturizing properties, also have issues such as irritation, dependence on air humidity for moisture absorption, or a tendency to cause a heavy film-like feeling.

[0003] Studies have shown that sugar derivatives can enhance the water-holding capacity of the stratum corneum by regulating the expression of aquaporin and promoting the synthesis of natural moisturizing factor (NMF). Xylitol glucoside not only enhances skin hydration but also improves skin barrier function and microecological balance. However, it is prone to charring and side reactions during traditional acid-catalyzed synthesis, affecting product color and stability, thus hindering industrial application. Therefore, developing a xylitol glucoside-type polysaccharide moisturizer with controllable reaction, thorough decolorization, structural purity, and excellent performance has become a pressing technical problem for the industry. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and to provide a xylitol glucoside polysaccharide moisturizer and its preparation method.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a polysaccharide moisturizer, comprising the following steps: (1) Xylitol was added to the reactor, along with an acidic catalyst. After heating to the point of melting, glucose was added. Glycosylation and dehydration reactions were carried out under vacuum. After the reaction was completed, deionized water was added to adjust the system to obtain the intermediate product. (2) Add alkali solution to the intermediate product to adjust the pH, and then add hydrogen peroxide for decolorization treatment to remove free hydrogen peroxide, so as to obtain the polysaccharide moisturizer xylitol glucoside.

[0006] As a further improvement of the present invention, the acidic catalyst in step (1) is p-toluenesulfonic acid.

[0007] As a further improvement of the present invention, the molar ratio of xylitol to glucose in step (1) is 1 to 1.5:1.

[0008] As a further improvement of the present invention, the reaction temperature in step (1) is 100-110°C and the reaction time is 4 h.

[0009] As a further improvement of the present invention, the alkaline solution in step (2) is a sodium hydroxide solution with a mass fraction of 30%, and the hydrogen peroxide has a mass fraction of 30%.

[0010] A second aspect of the present invention provides a xylitol glucoside polysaccharide moisturizer prepared by the above method.

[0011] In the electrospray ionization negative ion mode, with methanol and water at a volume ratio of 1:1 as the mobile phase and a mass error not exceeding ±5 ppm, molecular ion peaks of m / z 313.108±0.005, m / z 475.161±0.005, and m / z 637.214±0.006 were observed in the high-resolution mass spectrometry. Furthermore, the peak area ratios for polymerization degrees of 1, 2, and 3, as determined by high-performance liquid chromatography-evaporative light scattering (HPLC-ELISA), were 30%–55%, 25%–45%, and 10%–25%, respectively.

[0012] A third aspect of the present invention provides a cosmetic composition comprising 0.1 to 5% by weight of the above-mentioned polysaccharide moisturizer and a cosmetically acceptable carrier, wherein the composition has a pH of 4.5 to 6.5 at 25°C.

[0013] As a further improvement of the present invention, tested using standard skin bioengineering methods, compared with a blank matrix without the polysaccharide moisturizer, the stratum corneum moisture content is increased by not less than 10%, and transepidermal water loss is reduced by not less than 8%.

[0014] The fourth aspect of the present invention provides a cosmetic raw material liquid containing 5.0 to 30.0% by mass of the above-mentioned polysaccharide moisturizer, the solvent being water or a mixture of water and one or two of propylene glycol and glycerin, the pH being 4.5 to 6.5 at 25°C, and the color difference ΔE* after accelerated storage at 45°C for 28 days not exceeding 2.0.

[0015] The present invention, by adopting the above technical solution, has the following beneficial effects: 1. Using p-toluenesulfonic acid as a mild and efficient acid catalyst, a stable glycosylation reaction is achieved at a lower temperature, which significantly reduces the caramelization and side reactions of xylitol.

[0016] Compared to traditional glycosylation systems catalyzed by strong acids such as sulfuric acid and hydrochloric acid, p-toluenesulfonic acid exhibits stronger organic affinity and lower redox activity, enabling a stable condensation reaction within a medium-low temperature range of 100–110 °C. This condition avoids excessive dehydration of the xylitol terminal hydroxyl groups, preventing the formation of caramelization byproducts, while simultaneously inhibiting condensation and isomerization between glucose molecules. Experimental results show that the content of unreacted monosaccharides in the reaction system is reduced by approximately 40% compared to traditional strong acid systems, and the product color (Lovibond units) decreases by more than 50%. This improvement not only ensures the selective formation of the target glycosidic bond structure but also provides a lower impurity load for subsequent decolorization and purification processes, contributing to improved appearance and safety of the final product, demonstrating significant process innovation and industrial applicability.

[0017] 2. By combining vacuum glycosylation with subsequent hydrogen peroxide decolorization, a product with light color, high purity, and no irritating odor is obtained, which is suitable for use in cosmetic formulations.

[0018] Under vacuum reaction conditions, the oxygen partial pressure within the system is significantly reduced, effectively preventing oxidative browning and self-polymerization of reaction intermediates. Simultaneously, the negative pressure environment promotes timely removal of moisture, resulting in a more thorough glycosylation reaction and a substantial reduction in residual carboxyl or aldehyde groups. A subsequent hydrogen peroxide decolorization process utilizes its selective oxidizing properties to completely decompose residual organic pigments and intermediates. Free hydrogen peroxide is then removed through alkali neutralization, achieving system cleanliness. Comparative tests show that the product prepared using this process exhibits a color difference ΔE* ≤ 2.0 after accelerated storage at 45℃ for 28 days, with no off-odors, demonstrating significantly superior thermal stability and sensory characteristics compared to conventional acid-catalyzed systems. This combined process is the first to achieve an integrated pathway of "low-temperature glycosylation – vacuum control – oxidative purification," exhibiting non-obvious synergies in the preparation of similar polysaccharide humectants.

[0019] 3. The obtained xylitol glucoside has a significant free radical scavenging ability and can exert both antioxidant and moisturizing effects at the same time.

[0020] Free radical scavenging experiments verified that the scavenging rate of DPPH free radicals reached 5.95% at a mass fraction of 1.5%, and the scavenging rate of ABTS⁺ free radicals reached 30.49% at a mass fraction of 3%. This result indicates that the product molecule retains the multi-hydroxyl hydrogen-donating properties of xylitol while introducing an ether bond electron-donating site from the glucoside structure, forming a synergistic free radical scavenging pathway. Compared with the control samples (single xylitol or glucose), the scavenging rates increased by approximately 3 times and 5 times, respectively. This synergistic antioxidant effect not only helps delay the oxidative degradation of lipids in the stratum corneum but also inhibits skin barrier damage caused by UV stress, potentially providing auxiliary benefits in improving photoaging. Therefore, the product obtained in this invention not only possesses the hydrophilic and water-retaining properties of traditional moisturizers but also has active protective functions, expanding the application boundaries of polysaccharide moisturizers.

[0021] 4. Skin test results showed that after 2 hours of use at a dosage of 8.0 mg / cm², the moisture content of the stratum corneum increased by 81.26%, and transepidermal water loss was significantly reduced, demonstrating continuous moisturizing and barrier repair effects.

[0022] According to the standard testing method for skin bioengineering (Corneometer and Tewameter dual-probe method), skin tests on the subjects' arms revealed that using the polysaccharide moisturizer of this invention significantly increased the stratum corneum moisture content after 0.5 hours, and the upward trend continued after 2 hours, while transepidermal water loss (TEWL) continued to decrease. The results indicate that the product of this invention can form a uniform hydrophilic film on the skin surface and enhance the retention of water between keratinocytes by forming a hydrogen bond network with the stratum corneum's natural moisturizing factor (NMF) through its polyhydroxy segments. Compared with the blank matrix without this ingredient, the stratum corneum moisture content increased by 81.26%, and the TEWL decreased by more than 8%, far exceeding the comparative levels of commonly used moisturizers such as glycerin or propylene glycol. This result verifies that the xylitol glucoside of this invention possesses both immediate and long-lasting moisturizing properties and exhibits unexpected beneficial effects in barrier repair. Attached Figure Description

[0023] Figure 1 This is a high-resolution mass spectrum of the xylitol glucoside sample prepared in Example 1.

[0024] Figure 2 The graph shows the scavenging effect of xylitol glucoside obtained in Example 1 on DPPH free radicals.

[0025] Figure 3 The graph shows the scavenging effect of xylitol glucoside obtained in Example 1 on ABTS⁺ free radicals.

[0026] Figure 4 The graph shows the scavenging effect of xylitol glucoside obtained in Example 1 on hydroxyl radicals.

[0027] Figure 5 The xylitol glucoside obtained in Example 4 was tested at different dosages (2.0, 5.0, 8.0 mg / cm³). 2 The curve shows the test results of the effect on improving the moisture content of the stratum corneum.

[0028] Figure 6 The xylitol glucoside obtained in Example 4 was tested at different dosages (2.0, 5.0, 8.0 mg / cm³). 2 The curve shows the test results of the change in transdermal water loss (TEWL) in the skin. Detailed Implementation

[0029] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0030] Unless otherwise defined, all scientific and technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0033] The present invention will now be described in detail with reference to specific embodiments, which are intended to understand rather than limit the invention.

[0034] Example 1 This embodiment discloses a method for preparing a xylitol glucoside polysaccharide moisturizer, including the following steps: (1) Xylitol was poured into a reactor and p-toluenesulfonic acid was added as a catalyst. The mixture was heated at 100 °C for 0.5 h to completely melt the xylitol. Then, glucose with a molar ratio of 1.0:1.0 was added. The glycosylation and dehydration reactions were carried out under a vacuum of −0.09 MPa at a temperature of 100 °C for 4 h. After the reaction was completed, deionized water was added to adjust the system to obtain the intermediate product.

[0035] (2) Add 30% sodium hydroxide solution to the intermediate product to adjust the pH to neutral, then add 30% hydrogen peroxide for decolorization treatment, stir at 50 °C for 30 min, remove free hydrogen peroxide after decolorization, and obtain the polysaccharide moisturizer xylitol glucoside.

[0036] The resulting product is a light yellow transparent liquid with no odor. Mass spectrometry analysis showed obvious molecular ion peaks at m / z 313.108±0.005, m / z 475.161±0.005 and 637.214 ± 0.006, with peak area percentages of polymerization degrees 1, 2 and 3 being 53%, 32% and 15%, respectively.

[0037] Example 2 This embodiment discloses a method for preparing a xylitol glucoside polysaccharide moisturizer, including the following steps: (1) Pour xylitol into the reactor and add the catalyst p-toluenesulfonic acid. After melting at 100 °C for 0.5 h, add glucose with a molar ratio of xylitol to glucose of 1.2:1.0. Perform glycosylation and dehydration reaction under vacuum conditions at a temperature of 105 °C and a time of 4 h.

[0038] (2) After the reaction is complete, deionized water is added to adjust the system, and alkalization and decolorization are carried out in the same way as in Example 1 to obtain a light transparent liquid sample.

[0039] High-resolution mass spectrometry analysis revealed that the main molecular ion peaks also appeared at m / z 313.108±0.005, m / z 475.161±0.005, and m / z 637.214±0.006, indicating that the product is a complex system of xylitol-based mono, di, and triglucosides.

[0040] Example 3 This embodiment discloses a method for preparing a xylitol glucoside polysaccharide moisturizer, including the following steps: (1) Pour xylitol into the reactor and add the catalyst p-toluenesulfonic acid. After melting at 100 °C for 0.5 h, add glucose with a xylitol to glucose molar ratio of 1.3:1.0. Perform glycosylation and dehydration reaction under vacuum conditions at a temperature of 100 °C and a time of 4 h.

[0041] (2) After adjusting the system with deionized water and decolorizing it according to Example 1, a light yellow transparent liquid sample was obtained.

[0042] Liquid phase evaporation light scattering analysis showed that the product area ratios of polymerization degrees 1, 2, and 3 were 52%, 33%, and 15%, respectively, indicating stable product structures.

[0043] Example 4 This embodiment discloses a method for preparing a xylitol glucoside polysaccharide moisturizer, including the following steps: (1) Pour xylitol into the reactor and add the catalyst p-toluenesulfonic acid. After melting at 100 °C for 0.5 h, add glucose with a xylitol to glucose molar ratio of 1.5:1.0. Perform glycosylation and dehydration reaction under vacuum conditions at a temperature of 110 °C and a time of 4 h.

[0044] (2) Decolorization and neutralization were completed according to the method in Example 1 to obtain a colorless and transparent liquid sample.

[0045] After being stored at 45 ℃ for 28 days, the color difference ΔE* was measured to be 1.8, indicating good color and thermal stability.

[0046] Example 5 This embodiment provides a cosmetic composition containing xylitol glucoside polysaccharide moisturizer.

[0047] The product comprises, by weight percentage, the following components: xylitol glucoside (the product prepared in Example 1) 1.0%, glycerol 5.0%, propylene glycol 3.0%, carbomer 0.20%, triethanolamine 0.25%, preservative system (phenoxyethanol and ethylhexylglycerin) 0.8%, and the remainder being purified water.

[0048] The preparation method is as follows: Carbomer was added to purified water, dispersed evenly with stirring, and allowed to stand for 30 minutes to allow it to fully swell. Then, xylitol glucoside, glycerol, propylene glycol, and the preservative system were added sequentially to the system, stirring until completely dissolved to form a clear, homogeneous solution. Triethanolamine was then slowly added dropwise to adjust the pH to 5.5 ± 0.2, ensuring the carbomer was fully neutralized and formed a transparent gel. Finally, the solution was degassed, filtered, and filled into containers to obtain the finished product.

[0049] The resulting product is a colorless and transparent hydrogel with good fluidity, leaving a refreshing and non-sticky finish after application. No layering or separation was observed after 3 months of storage at room temperature, the pH remained within the range of 5.4–5.6, and its appearance and odor remained stable.

[0050] The stratum corneum hydration content and transepidermal water loss (TEWL) were tested using standard methods in skin bioengineering. Compared with a blank matrix without the polysaccharide moisturizer of this invention, after 2 hours of use, the stratum corneum hydration content increased by an average of 21.3%, and transepidermal water loss decreased by 9.6%, with statistically significant differences (p<0.05). The results indicate that xylitol glucoside can significantly enhance skin hydration capacity and strengthen the skin barrier's water-locking function.

[0051] Example 6 This embodiment provides a xylitol glucoside polysaccharide moisturizing agent raw material solution.

[0052] The product comprises, by weight percentage: 20.0% xylitol glucoside (the product prepared in Example 1), 10.0% propylene glycol, 70.0% purified water, and pH adjusted to 5.5 ± 0.2 with a citric acid-sodium citrate buffer system.

[0053] The preparation method is as follows: Xylitol glucoside was added to a mixed solvent of water and propylene glycol, and the mixture was slowly heated to 40°C with stirring until completely dissolved. After cooling to room temperature, a small amount of buffer solution was added to adjust the pH to 5.5 ± 0.2. Subsequently, the mixture was sterilized by 0.22 μm filtration and filled into sealed containers to obtain a clear and transparent cosmetic raw material solution.

[0054] The obtained raw material solution is a colorless and transparent fluid, odorless, with a viscosity of 150–200 mPa·s at 25°C and stable pH. After accelerated storage at 45°C for 28 days, the color difference ΔE* was measured to be 1.8, below 2.0, with no discoloration, precipitation, or off-odors, demonstrating excellent thermal stability and system compatibility. This raw material solution can be directly used as a moisturizing ingredient in cosmetic production, applied to various formulation systems such as emulsions, creams, masks, and serums.

[0055] Comparative Example 1 In the reaction system of Example 1, p-toluenesulfonic acid was omitted, and the other conditions were the same.

[0056] Comparative Example 2 Prepared according to the conditions of Example 2, but omitting the hydrogen peroxide decolorization step (2).

[0057] Performance testing 1. Antioxidant test The xylitol glucoside product prepared in Example 1 was used as a sample for the following tests.

[0058] (1) DPPH free radical scavenging: The DPPH free radical scavenging performance of the final product polysaccharide moisturizer was determined according to the experimental method of TSHRH006-2018 Cosmetics - Free Radical (DPPH) Scavenging. Figure 2 This describes the scavenging effect of xylitol glucoside on DPPH free radicals in Example 1. Figure 2 It can be seen that as the mass fraction of xylitol glucoside increases, the DPPH free radical scavenging rate rises to 5.95% and then stabilizes (reaching its maximum value at 1.5% mass fraction).

[0059] (2) ABTS free radical scavenging: Mix 0.1M phosphate buffer (pH 7.4) and ABTS at a 1:1 ratio, add an appropriate amount of H2O2, and incubate at room temperature for 30 minutes until the absorbance (734 nm) stabilizes at 0.7-0.8. Dilute the sample appropriately, add it to the ABTS solution, mix well, and incubate at room temperature for 10 minutes. Measure and record the absorbance (734 nm) using a spectrophotometer. Compare the antioxidant capacity of the sample with that of the standard substance, and calculate the antioxidant capacity of the sample based on the change in absorbance. Figure 3 The scavenging effect of xylitol glucoside on ABTS+ free radicals. (From...) Figure 3 It can be seen that when the mass fraction of xylitol glucoside is 3%, the clearance rate reaches 30.49%, which is concentration-dependent.

[0060] (3) Scavenging of hydroxyl radicals: Figure 4 This refers to the scavenging effect of xylitol glucoside on hydroxyl free radicals. (From...) Figure 4 It can be seen that the clearance rate was 22.17% when the xylitol glucoside mass fraction was 1.5%, and then tended to stabilize.

[0061] 2. Moisturizing performance test The xylitol glucoside product prepared in Example 4 was used as a sample for the following tests.

[0062] (1) Skin moisture content: Preparations of 2.0, 5.0, and 8.0 mg / cm³ were carried out. 2 Xylitol glucoside solution. The test environment was 20℃-22℃ and relative humidity 40%-60%. Subjects first washed their arms, and a 3 cm × 3 cm skin marker was randomly selected on the inner side. They sat quietly in the test room for 10 minutes. The prepared solution was applied to the test skin area, and the moisture content of the stratum corneum of the test skin was measured before application and 0.5 h and 2.0 h after application using a multi-probe skin testing system (MPA 10). Three points were randomly selected within the selected area, and the average of the three data points was used to determine the moisturizing performance of the natural polysaccharide-derived moisturizer. The final skin moisture content tests for 2.0, 5.0, and 8.0 mg / cm² xylitol glucoside solutions are as follows. Figure 5 As shown. By Figure 5 It can be seen that the higher the amount of xylitol glucoside used, the more significant the increase in water content. After 2 hours of use, the water content increased by 81.26% at 8.0 mg / cm2, and it was effective as early as 0.5 hours and continued to moisturize after 2 hours.

[0063] (2) Transdermal water loss: Xylitol glucoside solutions of 2.0, 5.0, and 8.0 mg / cm² were prepared. The test environment was maintained at 20℃-22℃ and 40%-60% relative humidity. Subjects first washed their arms, and a 3 cm × 3 cm skin marker was randomly selected on the inner side of the arm. Subjects sat quietly in the test room for 10 minutes. The prepared solutions were applied to the test skin area, and the TEWL (transepidermal water loss) values ​​were measured before application and at 0.5 h and 2.0 h after application using the Tewameter probe of an MPA 10 multi-probe skin testing system. Measurements were performed three times in parallel on the same skin area, and the average of the three stable data sets was used to determine the performance of the natural polysaccharide-derived moisturizer in reducing transepidermal water loss. The final results of the 2.0, 5.0, and 8.0 mg / cm² xylitol glucoside solutions for transepidermal water loss testing are as follows: Figure 6 As shown. By Figure 6 It can be seen that xylitol glucoside can reduce transdermal water loss, with a significant effect after 0.5 hours. Although the effect rebounds after 2 hours, it still has a water-locking effect, and it is positively correlated with the dosage.

[0064] Xylitol glucoside exhibits excellent moisturizing capabilities. With increasing dosage, the rate of change in skin moisture content increases, showing a clear dose-response relationship. Xylitol glucoside significantly increases skin moisture content after 0.5 hours of use, and continues to rise after 2 hours, indicating its sustained moisturizing ability. A dosage of 8.0 mg / cm² increases skin moisture content by 81.26% after 2 hours. Xylitol glucoside also has a certain ability to reduce transepidermal water loss. With increasing dosage, the rate of reduction in transepidermal water loss increases, showing a clear dose-response relationship. Transepidermal water loss is significantly reduced after 0.5 hours of use, and although it recovers somewhat after 2 hours, it still retains some water-locking effect.

[0065] Furthermore, the product prepared using the conditions of Comparative Example 1 without p-toluenesulfonic acid was light yellow, with a significantly darker color. Antioxidant capacity testing showed that the 1.5% solution scavenged approximately 2.8% of DPPH free radicals and [amount missing] ABTS. + The free radical scavenging rate was approximately 18.9%, significantly lower than the results of the previous examples. Skin tests showed that after 2 hours of use at a dosage of 8.0 mg / cm², the stratum corneum moisture content increased by only about 34.7%, and transepidermal water loss decreased by about 4%, indicating a weak moisturizing effect. This suggests that if p-toluenesulfonic acid is omitted, the glycosylation reaction is incomplete, resulting in more impurities and a significant decrease in the product's antioxidant and moisturizing properties.

[0066] The product prepared under the conditions of Comparative Example 2 without hydrogen peroxide decolorization was slightly yellow in color. Antioxidant testing showed that the 1.5% solution scavenged approximately 4.2% of DPPH free radicals and approximately 24.8% of ABTS⁺ free radicals, lower than the product in the example. Skin testing results showed that after 2 hours of use at a dosage of 8.0 mg / cm², the stratum corneum moisture content increased by approximately 56.4%, and transepidermal water loss decreased by approximately 6.3%, indicating a decrease in moisturizing effect compared to the example. This suggests that without decolorization, residual chromophores and intermediates will affect product purity and film-forming properties, thereby reducing moisturizing performance and stability.

[0067] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a xylitol-based glucoside polysaccharide moisturizer, characterized by, The method comprises the following steps: (1) adding xylitol into a reactor, adding an acidic catalyst, heating to melt, then adding glucose, and performing glycosylation and dehydration under vacuum, and adding deionized water to adjust the system after the reaction to obtain an intermediate product; (2) adding a lye to the intermediate product to adjust the pH, then adding hydrogen peroxide to perform decolorization treatment, and removing free hydrogen peroxide to obtain a polysaccharide moisturizer xylitol-based glucoside.

2. The method for preparing a xylitol-based glucoside polysaccharide moisturizer according to claim 1, characterized by, The acidic catalyst in step (1) is p-toluenesulfonic acid.

3. The method for preparing a xylitol-based glucoside polysaccharide moisturizer according to claim 1, characterized by, The molar ratio of xylitol to glucose in step (1) is 1-1.5:

1.

4. The method for preparing a xylitol-based glucoside polysaccharide moisturizer according to claim 1, characterized by, The reaction temperature in step (1) is 100-110°C, and the reaction time is 4 h.

5. The method of preparing a xylitol-based glucoside polysaccharide moisturizer according to claim 1, characterized by, The lye in step (2) is a 30% by mass sodium hydroxide solution, and the mass fraction of hydrogen peroxide is 30%.

6. The xylitol-based glucoside polysaccharide moisturizer prepared by the method of any one of claims 1-5.

7. The polysaccharide moisturizer of claim 6, wherein, In high-resolution mass spectrometry under negative ion mode of electrospray ionization with a methanol and water volume ratio of 1:1 as the mobile phase and a mass error of not more than ±5 ppm, the molecular ion peaks of m / z 313.108±0.005, m / z 475.161±0.005, and m / z 637.214±0.006 appear, and the peak area ratios of the polymerization degrees of 1, 2, and 3 are 30%-55%, 25%-45%, and 10%-25%, respectively, as measured by high-performance liquid evaporation light scattering detection.

8. A cosmetic composition characterized in that, The composition comprises 0.1-5% by mass of the polysaccharide moisturizer of claim 6 and a cosmetically acceptable carrier, and the pH of the composition is 4.5-6.5 at 25°C.

9. The cosmetic composition according to claim 8, characterized by Compared with a blank matrix without the polysaccharide moisturizer, the water content in the stratum corneum is increased by not less than 10%, and the transdermal water loss is reduced by not less than 8% as tested by a standard skin bioengineering method.

10. A cosmetic raw material solution, characterized by comprising: The composition comprises 5.0-30.0% by mass of the polysaccharide moisturizer of claim 6, the solvent is water or a mixture of water and one or both of propylene glycol and glycerol, the pH is 4.5-6.5 at 25°C, and the color difference ΔE* is not greater than 2.0 after 28 d of accelerated storage at 45°C.

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