A lipid-lowering sugar-free white tea probiotic fermentation liquor, a preparation method thereof and an application thereof

Abstract

The application provides a lipid-lowering sugar-free white tea probiotic fermentation liquor and a preparation method and application thereof, and belongs to the technical field of functional food processing. The method comprises the following steps: (1) white tea is crushed and sieved, then sterile distilled water is added, water extraction is performed in a boiling water bath, and finally cooling is performed; (2) probiotic powder is inoculated into the white tea culture medium obtained in step (1) for fermentation. The fermentation method provided by the application can effectively enrich flavonoids and polyphenolic compounds in the white tea water extract without adding glucose, and improve the content of various functional active ingredients such as hesperetin, quercetin, epigallocatechin and cinnamic acid. The sugar-free fermented white tea prepared by the application has a significantly improved flavonoid content compared with the sugar-containing white tea. The fermented white tea significantly reduces the oil and TC content of high-fat HepG2 cells, significantly improves the antioxidant activity, and reduces the expression amount of inflammatory factors. The application can provide ideas for further development of lipid-lowering functional foods mainly using white tea as a raw material, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of functional food processing technology, and in particular relates to a lipid-lowering sugar-free white tea probiotic fermentation liquid, its preparation method and application. Background Technology

[0002] Tea is a traditional non-alcoholic beverage, and its nutritional bioactive components and physiological functions are a research hotspot in the field of food science. Current research indicates that tea contains over 700 bioactive substances, constituting its unique nutritional chemical characteristics. Tea polyphenols are important nutrients in tea, accounting for approximately 20%-35% of the dry weight of tea leaves, of which 65%-80% are catechins. Tea polyphenols are related to the antioxidant, lipid-lowering, and blood sugar-lowering biological activities of tea. Another important nutrient in tea is tea polysaccharides, which can enhance free radical scavenging activity and have potential functions in preventing inflammation and obesity.

[0003] Based on its rich antioxidant content, tea has been proven to have lipid-lowering and anti-cancer effects. Numerous human intervention studies on green and black tea have shown that approximately one hour after drinking a moderate amount of tea (1-6 cups / day), the antioxidant capacity of human plasma significantly increases, and the enhanced blood antioxidant potential can reduce oxidative damage to macromolecules such as DNA and lipids. White tea can induce apoptosis in HCT116 cells by regulating the expression of apoptosis-related proteins Bcl-2 and Bax. The theaflavins in Pu-erh tea can reduce serum blood glucose and blood lipid concentrations in mice by activating gut microbiota with lipid-lowering activity.

[0004] Based on different processing techniques and fermentation levels, tea can be divided into six categories: green tea, white tea, black tea, yellow tea, oolong tea, and dark tea. White tea is a type of tea that is not processed by killing the green or rolling, but only by sun-drying or gentle drying; it belongs to the category of lightly fermented tea. Compared with fermented teas such as black tea and dark tea, white tea contains more catechins, represented by EGCG. Long-term consumption of white tea can significantly increase the activity of lipase and promote the decomposition of fat cells. However, white tea has a milder flavor, which limits its application in new-style tea drinks (such as milk tea and fruit tea) and tea-based foods. Therefore, adopting certain processing techniques to preserve the nutritional components of white tea and modify its flavor characteristics is of great significance for the application of white tea in the food industry.

[0005] Fermentation is an important food processing method that can increase the content of flavor compounds, enrich the taste, and further improve the nutritional value of food. However, most fermented tea drinks currently available require the addition of glucose for fermentation, making them unsuitable for people with specific conditions (such as diabetes or hyperlipidemia). Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a lipid-lowering, sugar-free white tea probiotic fermentation liquid, its preparation method, and its application. This invention utilizes *Lactobacillus rhamnosus* to ferment white tea under sugar-free conditions to enrich flavonoid active components, providing a theoretical basis for the development and application of probiotic-fermented white tea.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention first provides a method for preparing sugar-free white tea probiotic fermentation liquid, including the following steps: (1) Preparation of white tea culture medium: After the white tea leaves are crushed and sieved, sterile distilled water is added, and the mixture is extracted in a boiling water bath and then cooled. (2) Fermentation: Inoculate the probiotic powder into the white tea culture medium obtained in step (1) for fermentation to obtain sugar-free white tea probiotic fermentation liquid.

[0008] Preferably, in step (1), the white tea leaves are pulverized and sieved through a mesh size of 20-300.

[0009] Preferably, the mass ratio of white tea leaves to sterile distilled water in step (1) is 1:200.

[0010] Preferably, the boiling water bath extraction time in step (1) is 1 min to 20 min.

[0011] Preferably, the probiotic in step (2) is Lactobacillus rhamnosus YYS-B2.

[0012] Preferably, in step (2), the fermentation time is 12~60 h, the inoculum amount is 0.05%~0.25% (mass ratio), and the fermentation temperature is 37℃.

[0013] Furthermore, the present invention also provides a sugar-free white tea probiotic fermentation liquid prepared by the above preparation method.

[0014] Preferably, the maximum flavonoid content of the sugar-free white tea probiotic fermentation liquid is 0.627 mg / mL, at which point the probiotic powder addition is 0.14%, the fermentation time is 25 h, and the water extraction time is 12.5 min.

[0015] Furthermore, the present invention also provides the application of the above-mentioned sugar-free white tea probiotic fermentation liquid in the preparation of food, health products or pharmaceuticals with the function of reducing liver fat.

[0016] Preferably, the amount of sugar-free white tea probiotic fermentation liquid added is 3%-9%.

[0017] Preferably, the product has at least one of the following functions: (a1) to (a5): (a1) Reduces lipid and TC content in high-lipid HepG2 cells; (a2) Reduces reactive oxygen species content in high-lipid HepG2 cells; (a3) Regulates the decrease in antioxidant capacity of HepG2 cells caused by high-fat diet. (a4) Reduces the expression of inflammatory factors in hyperlipidemic HepG2 cells; (a5) Reduces the upregulation of genes related to lipid intake and de novo fat synthesis caused by high-fat intervention, including SLC27A2, SLC27A5, CD36, FASN and SCD genes.

[0018] Among them, the high-lipid HepG2 cells are high-lipid HepG2 cells induced by oleic acid and palmitic acid.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention utilizes *Lactobacillus rhamnosus* YYS-B2 to ferment white tea under sugar-free conditions to enrich flavonoids. The preparation process is simple and low-cost, and the flavonoid content increases by 21.38% compared to before fermentation. The fermented white tea obtained shows significantly enhanced DPPH and ABTS scavenging activity and good in vitro antioxidant activity. Metabolomics analysis shows that *Lactobacillus rhamnosus* fermentation increases the flavonoid content of white tea by activating the flavonoid biosynthesis pathway. Compared with sugar-fermented white tea, sugar-free fermented white tea has a significantly higher flavonoid content.

[0020] The preparation method provided by this invention can effectively enrich flavonoids and polyphenols in white tea water extracts, and increase the content of various functional active ingredients such as hesperidin, quercetin, epigallocatechin, and cinnamic acid. Fermented white tea significantly reduces the lipid and total cholesterol (TC) content in high-lipid HepG2 cells, significantly increases antioxidant activity, and reduces the expression of inflammatory factors.

[0021] (2) The sugar-free fermented white tea prepared in this invention can reduce the lipid and TC content of oleic acid / palmitic acid-induced HepG2 hyperlipidemia cells within a certain concentration range, effectively reduce ROS levels, reduce IL-6, IL-1β and TNF-α transcription levels, and increase SOD activity. Further studies have shown that fermented white tea exerts its lipid-lowering effect by reducing lipid intake and de novo fat synthesis. Attached Figure Description

[0022] Figure 1 The results of the optimization experiment of the white tea fermentation enrichment process in Example 1 of the present invention are shown. AD represents the effect of different probiotic freeze-dried powder addition, fermentation time, water extraction time and sieve mesh size on the flavonoid content of fermented white tea, and E is a 3D schematic diagram of the response surface fitting results. Figure 2The results of the test on the flavonoid and polyphenol content and antioxidant capacity of white tea before and after fermentation in Example 1 of the present invention are shown in Figure A, where A represents the change in flavonoid content before and after fermentation, B represents the change in polyphenol content before and after fermentation, and C and D represent the changes in the antioxidant indicators DPPH and ABTS scavenging rate before and after fermentation. Figure 3 The images show PLSDA analysis diagrams (A) and volcano diagrams (B) of the white tea metabolome before and after fermentation in Example 1 of this invention. Figure 4 The results of flavonoid content detection in sugar-free fermented white tea and sugar-containing fermented white tea in Comparative Example 1 of this invention; Figure 5 The effect of fermented white tea on lipid accumulation in high-lipid HepG2 cells in Experiment Example 1 of this invention. A and B are Oil Red O staining pathology and OD values, C is TG content, D is TC content, and E is cell activity. Figure 6 The effects of fermented white tea on reactive oxygen species levels, antioxidant capacity, and inflammatory factor levels in high-lipid HepG2 cells in Experiment Example 1 of this invention are shown in Figures A and B, which are ROS fluorescence images and relative fluorescence intensities. Figure C shows the cellular antioxidant indicators CAT and SOD activity, and Figure D shows the relative mRNA expression levels of inflammatory factors IL-1β, IL-6, and TNF-α. Figure 7 This study describes the effect of fermented white tea on the transcriptional levels of lipid metabolism-related genes in high-lipid HepG2 cells, as shown in Experimental Example 1 of this invention. Detailed Implementation

[0023] The following examples will further illustrate the specific steps and features of the invention. These examples are for illustrative purposes only and are not intended to limit the invention. Unless otherwise specified, the methods used in this invention are conventional methods in the art. Unless otherwise specified, all reagents and materials involved in this invention are commercially available. Example 1: Determination of White Tea Fermentation Process

[0024] 1. The materials and reagents used are listed in Table 1, and the instruments and equipment used are listed in Table 2.

[0025] Table 1 Main experimental materials

[0026] Table 2 Main equipment involved in the experiment

[0027] 2. The specific preparation process is as follows: (1) Preparation of white tea culture medium After grinding the white tea leaves into powder, sift them. Add sterile distilled water at a ratio of 1:200 (w / w), heat in a boiling water bath for a certain period of time to release the substances in the tea leaves, and then cool before use.

[0028] (2) Fermentation of white tea The freeze-dried powder of Lactobacillus rhamnosus YYS-B2 (culture preservation number CGMCC No. 28164, probiotic freeze-dried powder with an activity greater than 10) was used. 11 CFU / g) was inoculated into the white tea culture medium obtained in step (1) at a certain inoculation amount and fermented at 37℃ for a certain period of time.

[0029] 3. Process optimization (1) Determination of flavonoid content The flavonoid content in white tea was determined using spectrophotometry with rutin as a standard. Specifically, 1 mL of white tea supernatant was taken, 10 mL of 60% ethanol solution was added, vortexed, and then ultrasonically extracted at 45℃ for 40 min (ultrasonic power 200W). After extraction, the mixture was centrifuged at 4000 r / min for 10 min, and 8.7 mL of the supernatant was accurately transferred to a 10 mL volumetric flask. 150 μL of 5% sodium nitrite solution, 150 μL of 10% aluminum nitrate solution, and 1 mL of 4% sodium hydroxide solution were added, and the mixture was reacted in the dark for 15 min. 200 μL of each of the reaction liquids was pipetted into a 96-well plate, and the absorbance was measured at 510 nm using a microplate reader.

[0030] (2) Single-factor experiment Using flavonoid content as an indicator, this study investigated the effects of different amounts of freeze-dried probiotic powder added. Figure 1 (A) Fermentation time ( Figure 1 (B) Water extraction time ( Figure 1 (C) and sieve mesh ( Figure 1 The effect of D) on white tea fermentation was investigated under the following initial conditions: fermentation time 36 h, inoculum size 0.15%, water extraction time 10 min, and sieve mesh size 100 mesh. With increasing fermentation time, the flavonoid content first increased and then decreased, reaching its maximum at 36 h. Similarly, with increasing probiotic addition, the flavonoid content also first increased and then decreased, reaching its maximum at an addition of 0.15%. The highest flavonoid content was observed with water extraction time of 10 min and a sieve mesh size of 20 mesh. However, the tea powder uniformity was poor when sieved through 20 mesh; therefore, the sieve mesh size after tea powder pulverization was set at 200 mesh for further experiments.

[0031] (2) Response surface analysis Based on the Box-Behnken experimental design principle, fermentation time, probiotic freeze-dried powder dosage, and water extraction time were selected as optimization parameters. Each parameter had three levels, denoted as -1, 0, and 1, respectively. A three-factor, three-level response surface methodology (RSM) experiment was conducted. The experimental design and results are shown in Tables 3 and 4, and the response surface fitting results are shown in... Figure 2 E in Chinese.

[0032] Table 3 Experimental Design Table for Response Surface Analysis

[0033] The multiple quadratic regression simulation equations for the relationship between flavonoid content (Y) and three factors—probiotic freeze-dried powder addition amount (A), fermentation time (B), and water extraction time (C)—are as follows: Y=0.6089-0.0035A-0.0048B+0.0517C-0.0112AB-0.0131AC-0.0086BC-0.0248A 2 -0.0031B 2 -0.0488C 2 .

[0034] Table 4. Experimental Design and Results of Response Surface Optimization for Degree of Hydrolysis

[0035] Analysis of variance (Table 5) shows that the regression model P = 0.0013 (significant difference), lack of fit term P = 0.1648 (no significant difference), indicating that the model fits well.

[0036] Table 5. Results of ANOVA analysis of the response surface model

[0037] Based on the regression equation model, with the maximum flavonoid content as the optimization objective, the predicted optimal conditions are: 0.14% probiotic freeze-dried powder addition, 25 h fermentation time, and 12.5 min water extraction time, with a predicted maximum flavonoid content of 0.627 mg / mL.

[0038] The flavonoid content of fermented white tea was determined using optimal conditions. Figure 2 The model (A) found that the average flavonoid content of fermented white tea under these conditions was 0.637 mg / mL, and the relative error between the predicted value (0.627 mg / mL) and the actual value was 1.57%, indicating that the model has good predictive ability. Compared with before fermentation (flavonoid content 0.525 mg / mL), fermentation increased the flavonoid content in white tea by 21.3%.

[0039] 4. Verification of technical effectiveness (1) Determination of total phenol content and in vitro antioxidant capacity The total phenolic content of tea before and after fermentation was determined using the Folin-Ciocalteu method. Specifically, 1 mL of white tea supernatant was taken, 10 mL of anhydrous ethanol solution was added, and the mixture was ultrasonically extracted for 40 min. After centrifugation, 0.5 mL of the supernatant was transferred to a 10 mL volumetric flask, 1 mL of Folin-Ciocalteu solution and 3 mL of 8% sodium carbonate solution were added, and the mixture was brought to a final volume with anhydrous ethanol. The reaction was carried out in the dark for 1 min, and the absorbance was measured at 760 nm using a microplate reader. Gallic acid was used as the standard. The results showed that ( Figure 2 (B) The total phenolic content of fermented white tea was significantly higher than that before fermentation. P < 0.01) Improvement.

[0040] The DPPH and ABTS scavenging abilities were determined according to the national standard GB / T 39100-2020, "Determination of Antioxidant Activity of Polypeptides: DPPH and ABTS Methods". The scavenging rates of DPPH and ABTS free radicals by different concentrations of white tea samples were measured, and the half-maximal scavenging concentration (IC50) was calculated. Glutathione solution was used as a positive control. The test results are as follows: Figure 2 As shown in C and D. Compared with the unfermented group, the concentrations required for fermented white tea to achieve DPPH and ABTS half-maximum scavenging rates were significantly lower ( ). P < 0.01), indicating that fermentation can enhance the in vitro antioxidant activity of white tea.

[0041] (2) Non-targeted metabolomics detection Small molecule metabolites in white tea before and after fermentation were detected using UPLC-Q Exactive HF-X non-targeted metabolomics. PCA results ( Figure 3 (A) showed that the composition of white tea metabolites changed significantly before and after fermentation. Among them, the concentration of 439 substances increased after fermentation, while the concentration of 167 substances decreased after fermentation. Figure 3 Further research on the abundance changes of flavonoids and phenolic acids in differential metabolites revealed (Table 6) that, among 17 flavonoid compounds, 12 showed a significant increase in abundance after fermentation, and among 31 phenolic acid compounds, 26 showed a significant increase in abundance after fermentation. The abundance of cinnamic acid, an important precursor to flavonoid biosynthesis, significantly increased after fermentation, indicating that fermentation with *Lactobacillus rhamnosus* YYS-B2 may increase flavonoid content by activating the flavonoid biosynthesis pathway. Among the flavonoids, some flavonoids with lipid-lowering activity, such as hesperidin, quercetin, and epigallocatechin, showed a significant increase in content after fermentation, indicating that fermented white tea has a high lipid-lowering potential.

[0042] Table 6. Changes in the abundance of differential metabolites of flavonoids and phenolic acids in white tea before and after fermentation.

[0043]

[0044] Comparative Example 1: Detection of Flavonoid Content in Sugar-Free Fermented White Tea and Sugar-Fermented White Tea 1. The specific preparation process of sugar-fermented white tea is as follows: (1) After crushing the white tea leaves, sieve them. Mix 1 part tea leaves, 1 part glucose and 200 parts sterile distilled water, heat in a boiling water bath for a certain time to release the substances in the tea leaves, and then cool for later use.

[0045] (2) Step 2 is the same as in Example 1.

[0046] 2. Verification of technical effectiveness The flavonoid content of unsweetened fermented white tea and sugar-fermented white tea is as follows: Figure 4 As shown in the results, the sugar-fermented white tea prepared in Comparative Example 1 has a lower flavonoid content.

[0047] Experimental Example 1: Evaluation of the lipid-lowering effect of fermented white tea 1. Cell intervention and indicator analysis methods HepG2 cells were maintained in DMEM medium containing 10% fetal bovine serum and cultured at 37°C and 5% CO2. The medium was changed every two days, and cells were collected for intervention experiments when they reached 85% confluence. Cells were divided into five groups: normal control (NC), model group (FFA), low-dose fermented white tea intervention group (FTL), medium-dose fermented white tea intervention group (FTM), and high-dose fermented white tea intervention group (FTH), with five replicates per group. The FFA and fermented white tea intervention groups were induced using medium containing 0.5 mM oleic acid and 0.25 mM palmitic acid. The FTL, FTM, and FTH groups were further supplemented with 3%, 6%, and 9% fermented white tea, respectively. After 24 hours of intervention, cells were collected and the following indicators were measured: (1) Cell viability: Cells were cultured in 96-well plates, and CCK-8 reagent (10 μL / well) was added to the cells. The cells were cultured at 37°C for 2 hours, and the absorbance was measured at 450 nm.

[0048] (2) Oil Red O staining: Fix cells with paraformaldehyde for 10 min, wash with distilled water, soak in 60% isopropanol, and stain with Oil Red O solution for 10 min. Discard the staining solution, differentiate with 60% isopropanol until the intercellular matrix is ​​clear, wash with distilled water, and observe under a microscope. Discard the distilled water, add isopropanol until the staining solution is completely dissolved, and detect the absorbance at a wavelength of 490 nm.

[0049] (3) ROS fluorescence: Cells were cultured in black 96-well plates, the cell supernatant was discarded, 100 μL of 10 μM fluorescent probe DCFH-DA was added, and the cells were cultured in the dark for 30 min. After washing with serum-free culture medium, the fluorescence intensity was detected at an excitation wavelength of 488 nm and an emission wavelength of 525 nm. The fluorescence was observed under an inverted fluorescence microscope.

[0050] (4) Biochemical index analysis: The total TG and TC content in cells were detected using the TG (A110-1-1) and TC (A111-1-1) kits produced by Nanjing Jiancheng Biotechnology Research Institute Co., Ltd. The detection process was carried out in accordance with the instructions.

[0051] (5) Antioxidant index analysis: The CAT (A007-1-1) and SOD (A001-3-2) kits produced by Nanjing Jiancheng Bioengineering Research Institute Co., Ltd. were used to detect the CAT and SOD content in cells. The detection process was carried out in accordance with the instructions.

[0052] (6) mRNA expression analysis: Total RNA was isolated using the Simply P Total RNA Extraction Kit, and reverse transcription was performed using the Evo M-MLV Reverse Transcription Premixed Kit. Primers were synthesized by Shanghai Sangon Biotech Co., Ltd. qRT-PCR was performed using the SYBR GreenPro Taq HS Premixed qPCR Kit, and the relative mRNA expression level was expressed as a percentage of the total mRNA expression. -ΔΔCt express.

[0053] 2. Efficacy evaluation results (1) Effects of fermented white tea on lipid content and cell activity in high-lipid HepG2 cells The lipid content of HepG2 cells in each group was measured using Oil Red O staining. The lipids in the cells were stained red by Oil Red O solution. Figure 5 As shown in Figures A and B, compared with the NC group, lipid accumulation and significantly increased lipid content were observed in the cells of the FFA group. P < 0.01). Adding 3% and 9% fermented white tea reduced lipid accumulation, and cellular lipid content decreased significantly compared to the FFA group. P < 0.01). TG and TC levels in each group of cells were as follows: Figure 5 As shown in C and D, compared with the NC group, the TG ( ) of the FFA group P < 0.01) and TC ( P The content of < 0.05) was significantly increased, while fermented white tea showed a trend of reducing TG and TC levels in high-lipid HepG2 cells, with TC levels decreasing to a level not significantly different from that in the NC group. P > 0.05), and 6% added fermented white tea has the best effect in reducing TG and TC.

[0054] Cell viability in each group was detected using the CCK-8 assay. Figure 5 As shown in Figure E, compared with the NC group, high-lipid therapy significantly improved cell viability ( P < 0.05), and the cell activity of the fermented white tea intervention group was also increased compared with that of the NC group, indicating that fermented white tea does not have a toxic effect on HepG2 cells.

[0055] (2) Effects of fermented white tea on reactive oxygen species, antioxidants and transcriptional levels of inflammatory factors in high-lipid HepG2 cells ROS fluorescence results showed that ( Figure 6 In groups A and B, compared with the NC group, the ROS fluorescence intensity in the FFA group was significantly increased ( P <0.01, indicating that fat intake increases the reactive oxygen species content in HepG2 cells. After intervention with fermented white tea, compared with the FFA group, the ROS fluorescence intensity of all three intervention groups decreased significantly ( P < 0.01), fermented white tea can significantly reduce the reactive oxygen species content in high-lipid HepG2 cells.

[0056] Cellular CAT and SOD levels were studied, such as Figure 6 As shown in Figure C, CAT levels in the FFA group decreased significantly (P < 0.05), and SOD levels also showed a certain downward trend. Although fermented white tea intervention had a limited effect on CAT levels in high-lipid HepG2 cells, it significantly increased SOD levels. P < 0.05). This indicates that fermented white tea can, to some extent, regulate the decrease in antioxidant capacity of HepG2 cells caused by high lipid levels.

[0057] Furthermore, the mRNA transcription levels of inflammatory factors in HepG2 cells from each group were analyzed. The results showed ( Figure 6 In the middle D group, compared with the NC group, the IL-1β of HepG2 cells in the FFA group was higher. P < 0.05), IL-6 ( P < 0.01) and TNF ( P The mRNA transcription levels of cells with a concentration < 0.01 were significantly increased, indicating that fat intake leads to an increase in the inflammatory level of HepG2 cells. Different concentrations of fermented white tea intervention had varying effects on the expression levels of inflammatory factors in hyperlipidemic HepG2 cells. The 3% fermented white tea intervention showed the best effect, downregulating the expression levels of three inflammatory factors, while the 6% and 9% fermented white tea interventions showed downregulation of IL-6 and TNF.

[0058] (3) Effects of fermented white tea on the expression of lipid metabolism genes in high-lipid HepG2 cells Based on the preliminary study of the lipid-lowering effect of fermented white tea on hyperlipidemic HepG2 cells, the expression levels of lipid metabolism-related genes in each group of cells were further detected. For example... Figure 7 As shown, high-fat intervention increased the mRNA transcription levels of genes related to lipid uptake and de novo lipid synthesis in HepG2 cells, with SLC27A2, SLC27A5, CD36, FASN, and SCD showing significant increases compared to the NC group. P < 0.01). Fermented white tea significantly reduced lipid intake and upregulation of genes related to de novo liposynthesis induced by high-fat intervention, and no significant differences were observed among the three concentrations of fermented white tea. For fatty acid oxidation and triglyceride transport, fermented white tea did not correct the transcriptional changes in related genes induced by high-fat intervention. Therefore, fermented white tea mainly exerts its lipid-lowering effect on hyperlipidemic HepG2 cells by reducing lipid intake and de novo liposynthesis.

Claims

1. A method for preparing a lipid-lowering, sugar-free white tea probiotic fermentation liquid, characterized in that, Includes the following steps: (1) Preparation of white tea culture medium: After the white tea leaves are crushed and sieved, sterile distilled water is added, and the mixture is extracted in a boiling water bath and then cooled. (2) Fermentation: Inoculate the probiotic powder into the white tea culture medium obtained in step (1) for fermentation to obtain sugar-free white tea probiotic fermentation liquid.

2. The preparation method according to claim 1, characterized in that, The white tea leaves mentioned in step (1) are pulverized and sieved to a mesh size of 20-300.

3. As described in claim 1, characterized in that, The mass ratio of white tea leaves to sterile distilled water in step (1) is 1:

200.

4. The preparation method according to claim 1, characterized in that, The water extraction time in the boiling water bath in step (1) is 1 min to 20 min.

5. The preparation method according to claim 1, characterized in that, The probiotic mentioned in step (2) is Lactobacillus rhamnosus YYS-B2.

6. The preparation method according to claim 1, characterized in that, The fermentation time in step (2) is 12~60h, and the fermentation temperature is 37℃.

7. The preparation method according to claim 1, characterized in that, The inoculation amount of probiotic powder in step (2) is 0.05%~0.25%.

8. Sugar-free white tea probiotic fermentation liquid prepared by any of the preparation methods described in claims 1 to 7.

9. The use of the sugar-free white tea probiotic fermentation liquid as described in claim 8 in the preparation of products with the function of reducing liver fat.

10. The application according to claim 9, characterized in that, The product in question is food, health supplement, or medicine.

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