Composition for increasing cosmetic stability containing biological fermentation product and preparation method thereof

Abstract

The invention belongs to the technical field of fermentation engineering. More specifically, the invention relates to a new application of acetobacter xylinum fermented soybean milk and a fermented product thereof. The invention provides an acetobacter xylinum fermentation product, which is prepared by the following steps: inoculating acetobacter xylinum into a fermentation culture medium added with soybean milk and atriplex atriplex juice, culturing for 48-72 hours, and collecting fermentation supernatant, thereby obtaining the fermentation product. The invention accidentally finds that a product obtained by fermenting soybean milk and atriplex obscura juice by using acetobacter xylinum can obviously increase the stability of retinol and reduce the skin irritation caused by the retinol.

Description

Technical Field

[0001] The present invention belongs to the technical field of fermentation engineering. More specifically, it relates to a new application of fermenting soymilk with Acetobacter xylinum and the functional characteristics of its fermentation products. Background Art

[0002] Acetobacter xylinum is a microorganism with important application values in the fields of food, chemical industry, etc. Its cells are rod-shaped, generally sized 0.6 - 0.8μm × 1.0 - 4.0μm, arranged singly or in pairs, Gram-negative stained, without spores, with or without flagella, motile or non-motile. Acetobacter xylinum has a unique metabolic pathway, capable of metabolizing a variety of sugars and alcohols and converting them into various metabolites. In particular, it can synthesize bacterial cellulose from carbon sources such as glucose through a series of enzymatic reactions.

[0003] A large number of research reports at home and abroad have confirmed the antioxidant function of soybeans. Tocopherols, vitamin C, isoflavones, and phenolic compounds contained in soybeans all have antioxidant activities. Yamasaki et al. [1] found antioxidant activity in substances extracted from fermented soymilk. Geng et al. [2] By optimizing the fermentation conditions of lactic acid bacteria combinations, the free radical scavenging rate of acidified soymilk can reach 84.3%. Xu Yin et al. [3] proved through in vitro experiments that the DPPH scavenging rate and Fe 2+ chelating ability of fermented acidified soymilk increased significantly compared with that before fermentation, being 32.76% and 31.89% respectively.

[0004] Those skilled in the art know that usually, fermenting soymilk with different strains of bacteria can obtain products with different physiological activities. For example, Ruan Ziqi et al. [4] co-fermented with Bacillus natto and Lactobacillus casei to obtain acidified soymilk containing both nattokinase and pyrroloquinoline quinone. The mycelia of Grifola frondosa have high medicinal value. When used to ferment acidified soymilk, the contents of stachyose and raffinose are significantly reduced, and after fermentation, vitamin B1 and niacin increase from 3.27 and 3.84 mg·L -1 before fermentation to 10.82 and 8.74 mg·L -1[5] , respectively. And Nagino et al. [6] also found that acidified soymilk fermented with Lactobacillus casei can improve the bioavailability of isoflavones in women; Liu et al. [7] also found that acidified soymilk fermented with Lactobacillus plantarum has neuroprotective effects and can improve the learning and memory ability of rats. Currently, there are no reports on fermenting soymilk with Acetobacter xylinum and exploring the functional characteristics of its products.

[0005] [1]Yamasaki Y, Bakke M. Fermented soymilk extract and fermented hypocotyl extract: J.P., 2013082603[P]. 2014-06-19.

[0006] [2]Geng Y R, Li W J, Wang J M. Radical scavenging ability of soy milk fermented with compound lactic acid bacteria towards DPPH free radical[J]. Agricultural Science & Technology, 2015, 16(9): 2036-2039.

[0007] [3]Xu Yin, Huang Yujun, Chen Xia, et al. Study on the antioxidant effect of lactic acid bacteria-fermented soymilk in vitro and in vivo[J]. China Dairy Industry, 2012, 40(8): 16-19.

[0008] [4]Ruan Ziqi, Xu Weiwei, Wu Yuan, et al. Preparation method of an acidified soymilk rich in nattokinase and pyrroloquinoline quinone: China, 201410751782[P] 2014-12-10.

[0009] [5]Yang H, Zhang L, Xiao G, et al. Changes in some nutritional components of soymilk during fermentation by the culinary and medicinal mushroom Grifola frondosa[J]. LWT - Food Science and Technology, 2015, 62(1): 468-473. SUMMARY OF THE INVENTION

[0010] The present invention relates to Acetobacter xylinum, the product obtained by fermenting soymilk with Acetobacter xylinum, the characteristics of the product and its applications. The present invention unexpectedly discovers that the product obtained by fermenting soymilk and Atriplex nummularia L. juice with Acetobacter xylinum can significantly increase the stability of retinol and reduce the skin irritation caused by it.

[0011] In particular, the increase in the stability of retinol described herein includes increasing the stability of retinol or retinol-containing products, and the products are drugs, cosmetics, etc.

[0012] The above object of the present invention is achieved by the following technical solutions:

[0013] The present invention provides a fermentation product of Acetobacter xylinum. The Acetobacter xylinum is inoculated into a fermentation medium added with soy milk and cultured for 48 to 72 hours, and the fermentation supernatant is collected to obtain the fermentation product.

[0014] In this article, the period of time is preferably 48 to 72 hours. The fermentation time is very important for obtaining a fermentation product with ideal functional characteristics. Different fermentation durations will cause various changes in the nutritional components of the fermentation product. For example, certain components such as vitamins will accumulate, and at the same time, some special metabolites may be produced. These changes endow the product with different new characteristics.

[0015] In one embodiment of the present invention, the biological deposit number of the Acetobacter xylinum is: ATCC 23769. A large number of screening and comparative tests have also been carried out in the selection of strains. The fermentation products produced after over-fermentation by lactic acid bacteria (Lactobacillus acidophilus) and yeast (Saccharomyces boulardii) have no similar effects.

[0016] In one embodiment of the present invention, 3 to 10% by weight of Atriplex nummularia juice is further added to the fermentation medium. Adding Atriplex nummularia juice is essential for achieving the object of the present invention. The aforementioned "and this supernatant unexpectedly showed an unexpected effect of stabilizing retinol and reducing its skin irritation" are all based on the addition of Atriplex nummularia juice. Because the results of comparative tests show that the fermentation supernatant obtained without adding Atriplex nummularia juice showed completely opposite effects.

[0017] In one embodiment of the present invention, the Atriplex nummularia juice is obtained by juicing its stems and leaves. The juicing can be carried out by any method of the prior art, such as pressing method, grinding method, enzymatic hydrolysis method, ultrasonic method, and microwave method, etc. The present invention preferably uses the ultrasonic method. The specific operation can be: select fresh Atriplex nummularia, wash its stems and leaves, break them, add 3 to 6 times of deionized water, place them under ultrasonic waves for extraction for 10 to 60 minutes, the ultrasonic frequency is 60 to 80 kHz, the ultrasonic power is 100 to 200 W, and the temperature is controlled between 30 and 50 °C; after the ultrasonic treatment, the obtained mixture is filtered and centrifuged to obtain the Atriplex nummularia juice.

[0018] During the preparation process of the above Atriplex nummularia juice, the filtration is usually carried out through filter paper, filter screen or filtration equipment, aiming to remove the solid residues therein to obtain the juice.

[0019] During the preparation process of the above-mentioned Atriplex nummularia juice, centrifugation is used to remove the small particles or suspended substances that still remain after filtration. Through centrifugation, solid impurities can be precipitated to the bottom of the centrifuge tube to obtain a relatively clear juice. The rotation speed of the centrifugation can be 3000 - 10000 revolutions per minute, and the centrifugation time is 5 - 10 minutes.

[0020] In one embodiment of the present invention, the soy milk is obtained by grinding soybeans, followed by filtration, homogenization, and sterilization. Briefly, this technological process includes steps of washing, soaking, grinding, boiling, homogenizing, and sterilizing soybeans.

[0021] Specifically, the detailed preparation steps are as follows: After removing impurities and rinsing soybeans clean, add deionized water at a material-liquid ratio of 1:3 - 10, add 0.1 - 0.5% NaHCO3 solution and soak for 1 - 12 h, add deionized water at a material-liquid ratio of 1:3 - 10 and hot grind at 80 - 100 °C for 10 - 30 min, pass through a 100-mesh sieve, homogenize at 10 - 30 MPa for 5 - 10 min, sterilize and cool to obtain soy milk.

[0022] In one embodiment of the present invention, the addition amount of soy milk in the medium is 10 - 35%.

[0023] In one embodiment of the present invention, the medium is Hestrin-Schramm medium. Herein, the Hestrin-Schramm (HS) medium contains 20 g / L of glucose, 5 g / L of peptone, 5 g / L of yeast extract, 2.7 g / L of potassium dihydrogen phosphate, 0.2 g / L of magnesium sulfate heptahydrate, and the pH is 5.5 - 6.0.

[0024] In one embodiment of the present invention, the fermentation parameters are as follows: the inoculation amount of Acetobacter xylinum is 3 - 10%; the fermentation temperature is 25 - 30 °C; the fermentation pH is 5.0 - 6.0; the aeration rate is 0.5 - 1.5 vvm; the stirring speed is 100 - 300 r / min; the tank pressure is 0.05 - 0.15 MPa.

[0025] The present invention also provides the use of the fermentation product of Acetobacter xylinum in enhancing the stability of retinol or its derivatives.

[0026] In this article, stability refers to the stability of retinol in solutions with different pH values and solutions containing metal ions. Experiments have shown that the stability of retinol solution is poor in solutions with pH 2.0 and pH 10.0. The test results show that the remaining rates of retinol after incubation at 37°C for 5 days are about 58% and 35% respectively, and it is relatively stable at pH 6.0 - 8.0. After adding the fermentation product of Acetobacter xylinum of the present invention, the retinol solution can exist relatively stably in acidic and alkaline solutions (pH 2.0 - 10.0), and the remaining rates after incubation at 37°C for 5 days are all above 85%. This indicates that the fermentation product of Acetobacter xylinum can improve the stability of retinol in acidic and alkaline solutions, but the specific mechanism of action remains to be further studied.

[0027] In addition, it has been proven that the presence of Fe 3+ relatively affects the stability of retinol, and as the concentration of Fe 3+ increases, the destructive effect on retinol becomes stronger. After incubation at 37°C for 5 days in a solution with a high concentration of Fe 3+ (10 mmol / L), the remaining rate of retinol is only about 50%. It is observed that the color of retinol changes to brownish-yellow, which may be due to the oxidative degradation of retinol. After adding the fermentation product of Acetobacter xylinum, after incubation at 37°C for 5 days in a solution with the same concentration of Fe 3+ , the remaining rate of retinol is 90%. This indicates that the fermentation product of Acetobacter xylinum can significantly improve the stability of retinol in Fe 3+ solution, and there is a significant difference compared with the case without addition (P < 0.01).

[0028] Regrettably, the fermentation product of Acetobacter xylinum obtained in the present invention cannot improve the photo-stability of retinol.

[0029] The present invention also provides the use of the above-mentioned fermentation product of Acetobacter xylinum in reducing the skin irritation caused by retinol or its derivatives.

[0030] The results of the irritation test show that, in addition to the aforementioned functions, unexpectedly, the irritation of the mixture of this fermentation product of Acetobacter xylinum and retinol is surprisingly low.

[0031] The realization of the above functions depends on the presence of the fermentation product of Acetobacter xylinum obtained by a specific preparation method. Description of the Drawings

[0032] Figure 1 It is a picture of Acetobacter xylinum cells.

[0033] Figure 2 It is the change in the TEWL difference before and after the use of the fermentation product of Acetobacter xylinum / retinol emulsion in each group;

[0034] Among them, compared with the control group, *P < 0.05, ** P < 0.01. Specific implementation mode

[0035] The following is further described in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

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

[0037] The HS medium described herein contains 20 g / L of glucose, 5 g / L of peptone, 5 g / L of yeast extract, 2.7 g / L of potassium dihydrogen phosphate, 0.2 g / L of magnesium sulfate heptahydrate, and the pH is 5.5 - 6.0.

[0038] Example 1 Preparation of Acetobacter xylinum fermentation product

[0039] (1) Preparation of soy milk: After removing impurities and rinsing soybeans clean, add deionized water according to a solid-liquid ratio of 1:6, add 0.25% NaHCO3 solution and soak for 3 h, add deionized water according to a solid-liquid ratio of 1:10, heat-mill at 100 °C for 30 min, pass through a 100-mesh sieve, homogenize at 25 MPa for 8 min, sterilize and cool to obtain soy milk;

[0040] (2) Preparation of Atriplex nummularia juice: Select fresh Atriplex nummularia, wash its stems and leaves, break them, add 6 times of deionized water, place them under ultrasonic waves for 30 minutes, the ultrasonic frequency is 60 kHz, the ultrasonic power is 150 W, and the temperature is controlled between 45 °C; after the ultrasonic treatment, filter the obtained mixture, centrifuge at 3000 r / min for 5 min, and take the supernatant to obtain the Atriplex nummularia juice;

[0041] (3) Strain activation: In a clean bench, pick up a small amount of Acetobacter xylinum with an inoculation loop, and under sterile conditions, inoculate it into the prepared solid slant medium (HS medium + 1.5% agar, pH 5.5 - 6.0), gently slide it on the slant to make the strain evenly distributed on the slant; put the inoculated medium into a constant temperature incubator and culture it at 28 - 30 °C for 24 h until obvious colonies appear on the medium, and collect the bacteria;

[0042] (4) Fermentation: Add 25 wt% of soy milk and 8 wt% of Atriplex nummularia juice to the HS medium to obtain a fermentation medium, inoculate 5% of Acetobacter xylinum into the fermentation medium and ferment for 48 - 72 h, the fermentation temperature is 28 °C; the fermentation pH is 5.5 - 6.0; the ventilation rate is 1.0 vvm; the stirring speed is 150 r / min; the tank pressure is 0.1 MPa; collect the fermentation supernatant, filter it through a 0.22 μm ultrafiltration membrane, and collect the filtrate to obtain the Acetobacter xylinum fermentation product.

[0043] Example 2 Preparation of the Fermentation Product of Acetobacter xylinum

[0044] (1) Preparation of soymilk: After removing impurities and rinsing soybeans thoroughly, add deionized water according to a solid-liquid ratio of 1:3, add 0.25% NaHCO3 solution and soak for 2 h, add deionized water according to a solid-liquid ratio of 1:10, heat-mill at 80 °C for 30 min, sieve through a 100-mesh sieve, homogenize at 20 MPa for 10 min, sterilize and cool to obtain soymilk;

[0045] (2) Preparation of Atriplex nummularia L. juice: Select fresh Atriplex nummularia L., wash its stems and leaves, crush them, add 3 times deionized water, place under ultrasonic wave for 15 min, ultrasonic frequency is 860 kHz, ultrasonic power is 200 W, and the temperature is controlled between 50 °C; after ultrasonic treatment, filter the obtained mixture, centrifuge at 3000 r / min for 10 min, take the supernatant to obtain the Atriplex nummularia L. juice;

[0046] (3) Strain activation: In a clean bench, use an inoculation loop to pick a small amount of Acetobacter xylinum, and inoculate it into the prepared solid slant medium (HS medium + 1.5% agar, pH 5.5 - 6.0) under sterile conditions, gently slide on the slant to make the strain evenly distributed on the slant; put the inoculated medium into a constant temperature incubator, culture at 28 - 30 °C for 24 h until obvious colonies appear on the medium, and collect the bacterial cells;

[0047] (4) Fermentation: Add 10 wt% soymilk and 10 wt% Atriplex nummularia L. juice to the HS medium to obtain a fermentation medium, inoculate 3% Acetobacter xylinum into the fermentation medium and ferment for 48 h, fermentation temperature is 28 °C; fermentation pH is 5.5 - 6.0; aeration rate is 1.0 vvm; stirring speed is 150 r / min; tank pressure is 0.1 MPa; collect the fermentation supernatant, filter through a 0.22 μm ultrafiltration membrane, collect the filtrate to obtain the fermentation product of Acetobacter xylinum.

[0048] Example 3 Preparation of the Fermentation Product of Acetobacter xylinum

[0049] (1) Preparation of soymilk: After removing impurities and rinsing soybeans thoroughly, add deionized water according to a solid-liquid ratio of 1:10, add 0.25% NaHCO3 solution and soak for 12 h, add deionized water according to a solid-liquid ratio of 1:10, heat-mill at 100 °C for 30 min, sieve through a 100-mesh sieve, homogenize at 25 MPa for 5 min, sterilize and cool to obtain soymilk;

[0050] (2) Preparation of Atriplex nummularia juice: Select fresh Atriplex nummularia, wash its stems and leaves, crush them, add 5 times deionized water, place it under ultrasonic wave for 60 minutes, the ultrasonic frequency is 60 kHz, the ultrasonic power is 100 W, and the temperature is controlled between 35 °C; after the ultrasonic treatment, filter the obtained mixture, centrifuge at 3000 rpm for 5 minutes, take the supernatant to obtain the Atriplex nummularia juice;

[0051] (3) Strain activation: In a laminar flow hood, use an inoculation loop to pick a small amount of Acetobacter xylinum, and inoculate it into the prepared solid slant medium (HS medium + 1.5% agar, pH 5.5 - 6.0) under sterile conditions, and gently slide it on the slant to make the strain evenly distributed on the slant; put the inoculated medium into a constant temperature incubator and culture it at 28 - 30 °C for 24 h until obvious colonies appear on the medium, and collect the bacteria; (4) Fermentation: Add 35 wt% soy milk and 3 wt% Atriplex nummularia juice to the HS medium to obtain a fermentation medium, inoculate 5% activated Acetobacter xylinum into the fermentation medium and ferment for 72 h, the fermentation temperature is 28 °C; the fermentation pH is 5.5 - 6.0; the aeration rate is 1.0 vvm; the stirring speed is 150 r / min; the tank pressure is 0.1 MPa; collect the fermentation supernatant, filter it through a 0.221 μm ultrafiltration membrane, and collect the filtrate to obtain the fermentation product of Acetobacter xylinum.

[0052] Comparative Example 1: The difference from Example 1 is that Atriplex nummularia juice is not added during the fermentation process in step (4), and the other parameters are the same as those in Example 1.

[0053] Comparative Example 2: The difference from Example 1 is that truffle extract (purchased from Shanghai Haotai Biotechnology Co., Ltd.) is added during the fermentation process in step (4), and the other parameters are the same as those in Example 1.

[0054] Comparative Example 3: The difference from Example 1 is that Lactobacillus acidophilus is used to replace Acetobacter xylinum, and the fermentation parameters are: the medium is MRS medium, fermented in a shaker at 37 °C, the pH is 5.5 - 6.5, the shaker speed is 150 r / min, the aeration rate is 1.0 vvm, and the other parameters are the same as those in Example 1.

[0055] Comparative Example 4: The difference from Example 1 is that Saccharomyces boulardii is used to replace Acetobacter xylinum, and the fermentation parameters are: the medium is YPD medium, fermented in a shaker at 30 °C, the pH is 5.0 - 6.0, the aeration rate is 1.0 vvm, the shaker speed is 1500 r / min, and the other parameters are the same as those in Example 1.

[0056] pH Stability Test

[0057] Solutions with pH values of 2, 4, 6, 8, and 10 were prepared by using phosphate buffer solutions with different pH values and 100% DMSO solution. An appropriate amount of retinol was accurately weighed and dissolved in the above solutions with different pH values respectively to prepare retinol solutions with the same concentration (1%) to ensure complete dissolution of retinol. The fermentation products of Acetobacter xylinum from Example 1 and Comparative Examples 1-4 were added to the above retinol solutions respectively, ensuring that the weight ratio of the fermentation products of Acetobacter xylinum to retinol was 1:0.5. After mixing evenly, the pH of each group of sample solutions was calibrated (the addition of the fermentation products of Acetobacter xylinum would cause a deviation in the pH of the solution). Each sample tube was placed in an incubator (37°C) for 5 days. Then the samples were taken out, and the content of retinol in each sample tube was determined by high performance liquid chromatography (HPLC). Each sample was replicated 6 times. The retinol solution without the addition of the fermentation products of Acetobacter xylinum was used as the control group, and the remaining rate of retinol at different pH values was calculated. The results are shown in Table 1 below.

[0058] Remaining rate = (retinol content after incubation - retinol content before incubation) / retinol content before incubation × 100%

[0059] Table 1

[0060]

[0061] Note: Compared with the control group, * P < 0.05, ** P < 0.01.

[0062] Analysis of Table 1 shows that retinol has poor stability in solutions with pH 2.0, 4.0, and pH 10.0, and the remaining rates are about 58%, 62%, and 35% respectively. After adding the fermentation products of Acetobacter xylinum from Example 1, the stability of retinol in solutions with different pH values has been significantly improved. Especially under acidic and alkaline conditions, the remaining rate of retinol is above 85%, and the highest can reach 96%. Analysis of the results of other comparative examples shows that the fermentation products of Acetobacter xylinum prepared without adding the juice of Atriplex nummularia L. and the fermentation products of Acetobacter xylinum prepared by replacing Acetobacter xylinum with Lactobacillus acidophilus showed opposite effects to those of Example 1, and the remaining rate of retinol was significantly lower than that of the control group (P < 0.05); the fermentation products of Acetobacter xylinum prepared by adding truffle extract had no obvious effect on the stability of retinol, but did not show the opposite effect either; the fermentation products of Acetobacter xylinum prepared by replacing Acetobacter xylinum with Saccharomyces boulardii had a certain improvement effect on stabilizing retinol in acidic and alkaline solutions, but the intensity was not as good as that of Example 1.

[0063] Metal ion influence test

[0064] Preparation of solutions: Retinol was prepared into a 1% ethanol solution, divided into 18 equal parts, and randomly divided into 3 groups, with 6 parts in each group, corresponding to three concentrations of ferric chloride solutions (0.1 mmol / L, 1 mmol / L, and 10 mmol / L). The fermentation products of Acetobacter xylinum from Example 1 and Comparative Examples 1-4 were added to 6 parts of each group, and the remaining 1 part was used as a blank control group. The solutions were mixed evenly to obtain mixed solutions. Different concentrations of FeCl3 solutions were added to the three groups of mixed solutions so that their final concentrations were 0.1 mmol / L, 1 mmol / L, and 10 mmol / L, respectively. After incubating the samples in each group at 37 °C for 5 days, the content of retinol was detected by HPLC, and the remaining rate of retinol was calculated. The results are shown in Table 2 below.

[0065] Table 2

[0066]

[0067]

[0068] Note: Compared with the control group, * P < 0.05, ** P < 0.01.

[0069] Analysis of Table 2 shows that retinol has poor stability in a 10.0 mmol / L iron ion solution. Only 50% of the retinol remains after incubating at 37 °C for 5 days, and the damage rate reaches 50%. However, after adding the fermentation product of Acetobacter xylinum from Example 1, the stability of retinol in iron ion solutions with different concentrations is significantly improved, and the loss rate in a 10.0 mmol / L iron ion solution is less than 10%. Analysis of the results of other comparative examples shows that the fermentation product of Acetobacter xylinum prepared by adding black truffle extract has a certain effect on stabilizing retinol in iron ion solutions with concentrations of 0.1 mmol / L and 1 mmol / L, but a similar effect is not observed in high-concentration iron ion solutions. The fermentation product of Acetobacter xylinum prepared without adding the juice of Atriplex nummularia has no obvious effect on stabilizing retinol in low-concentration iron ion solutions, but the opposite effect is observed in high-concentration iron ion solutions. The fermentation product of Acetobacter xylinum prepared by replacing Acetobacter xylinum with Lactobacillus acidophilus and the fermentation product of Acetobacter xylinum prepared by replacing Acetobacter xylinum with Saccharomyces boulardii do not show similar improvement or opposite effects in iron ion solutions with different concentrations.

[0070] Irritation test

[0071] Preparation of retinol emulsion: Weigh 0.35 g of carbopol into a 200 mL beaker, add 7.5 g of glycerol, and then add 79.55 g of deionized water. Heat to 75 - 80 °C and stir to obtain Phase A. Weigh 0.5 g of p-hydroxyacetophenone and 0.5 g of 1,2 - hexanediol into a small beaker, stir at 60 - 70 °C until completely dissolved to obtain Phase B. Add retinol and the fermentation product of Acetobacter xylinum in Example 1 (with weights of 1% and 2% respectively), stir evenly at 75 - 80 °C until completely dissolved to obtain Phase C. Add Phase C to Phase A at 75 - 80 °C, disperse for 5 - 10 min, then cool down to 40 °C, add Phase B, and adjust the pH to about 6.0 to obtain the emulsion sample of Example 1. Prepare the emulsion samples of Comparative Examples 1 - 4 according to the above method, and use the retinol emulsion without the fermentation product of Acetobacter xylinum as the blank control group.

[0072] Screening of retinol - sensitive populations: Apply 1 g of the emulsion sample containing only retinol to the inner side of the forearm of the subjects, smear evenly in circles 20 times, apply once in the morning and once in the evening for 2 consecutive days, and select the subjects who give feedback of stinging, burning, and pain. A total of 30 subjects meeting this standard were selected for the irritation test.

[0073] Steps of the irritation test: Randomly divide the 30 subjects into six groups, with 5 people in each group. Before the experiment, rinse the inner wall of the front side of the arms of each group of subjects with water, wipe clean, and wait for 30 min in a constant temperature and humidity environment (temperature 20 - 22 °C, humidity 40% - 60%). Draw six square areas on the inner side of the left forearm of each subject, with each area sized 2×2 cm, and measure the TEWL value of each area before applying the sample using a Tewameter RTM Hex. Apply the sample emulsion to the six square areas respectively, take 1 g of the sample and smear evenly in circles 20 times, apply once in the morning and once in the evening for 2 consecutive days, and measure the TEWL value of the applied area on the third day. Organize the collected data and analyze the differences through statistical methods. The results are shown in Table 3 and Figure 2 as follows.

[0074] TEWL difference = TEWL value after use - TEWL value before use

[0075] Table 3

[0076] Group Change in average TEWL value before and after use Blank control group 1.35 Example 1 -0.44 Comparative example 1 0.89 Comparative example 2 -0.12 Comparative example 3 1.67 Comparative example 4 0.53

[0077] The results are shown in Table 3 and Figure 2 as follows. After using the solution containing only retinol, the TEWL of the subjects increased, indicating that the transdermal water loss of the skin increased after using retinol and the skin barrier was significantly damaged; while after applying the emulsion samples added with the fermentation product of Acetobacter xylinum in Example 1 and Comparative Example 2, the TEWL value of the subjects' skin became smaller, showing less irritation to the skin.

[0078] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A Gluconacetobacter fermentation product, characterized in that, Inoculate Acetobacter xylinum into a fermentation medium supplemented with soy milk and culture for 48 to 72 hours, and collect the fermentation supernatant to obtain the fermentation product.

2. The fermentation product according to claim 1, wherein The biological deposit number of the Acetobacter xylinum is: ATCC23767.

3. The fermentation product according to claim 1, wherein The fermentation medium is further supplemented with 3 to 10% by weight of Atriplex nummularia juice.

4. The fermentation product according to claim 3, characterized in that, The Atriplex nummularia juice is obtained by juicing its stems and leaves and then filtering.

5. The fermentation product according to claim 1 or 2, characterized in that, The soy milk is obtained by grinding soybeans, followed by filtration, homogenization, and sterilization.

6. The fermentation product according to claim 3, wherein The addition amount of soy milk in the medium is 10 to 35%.

7. The fermentation product according to claim 4, wherein, The medium is Hestrin-Schramm medium.

8. The fermentation product according to any one of claims 1 to 7, characterized in that, The fermentation parameters are as follows: the inoculation amount of Acetobacter xylinum is 3 to 10%; the fermentation temperature is 25 to 30 °C; the fermentation pH is 5.0 to 6.0; the aeration rate is 0.5 to 1.5 vvm; the stirring speed is 100 to 300 r / min; the tank pressure is 0.05 to 0.15 MPa.

9. Use of the Acetobacter xylinum fermentation product according to any one of claims 1 to 8 in enhancing the stability of retinol or its derivatives.

10. Use of the Acetobacter xylinum fermentation product according to any one of claims 1 to 8 in reducing skin irritation caused by retinol or its derivatives.

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