A pueraria powder composition having a fat-reducing effect and a preparation method thereof

Abstract

The present application relates to a kind of pueraria powder composition with fat-reducing effect and preparation method thereof, belong to fermentation product preparation technical field, including the following preparation steps: pueraria is classified and washed, gradient temperature pre-gelatinization is added, enzyme activator is adjusted pH value, constant temperature stirring is low pressure microburst, sterilization is optimized, and pueraria fermentation base material is prepared;Compound probiotics are activated by preparing pueraria base special activated culture medium, and compound bacterial liquid is prepared;Compound bacterial liquid is connected into pueraria fermentation base material and carries out synergistic anaerobic fermentation, after ripening, freezing granulation drying, sterile packaging, and pueraria powder composition is prepared.The technical scheme in the present application, by pueraria pretreatment process, active ingredients in pueraria are released and puerarin glycoside is realized, and human absorption rate is improved, while using the synergistic effect of compound probiotics and pueraria active ingredients, can effectively reduce weight, reduce abdominal fat accumulation, and overall improve the fat-reducing effect of pueraria powder composition.

Description

Technical Field

[0001] This invention belongs to the field of fermentation product preparation technology, specifically, it relates to a kudzu root powder composition with fat-reducing effect and its preparation method. Background Technology

[0002] As a food and medicine source, kudzu root is rich in active ingredients such as puerarin and flavonoids, which have the potential to regulate blood lipids and inhibit fat synthesis. However, kudzu root itself has a layered and dense fiber structure, high starch content, and most of its active ingredients exist in the form of glycosides. Direct consumption results in low dissolution rate and poor human absorption. Conventional kudzu root pretreatment only involves simple crushing and sterilization, which cannot adapt to the unique physical properties of kudzu root and easily leads to the loss of active ingredients. Moreover, single-strain fermentation has limited effect on improving the fat-reducing effect of kudzu root.

[0003] Currently, existing pretreatment processes for fermented kudzu products are generally applicable but lack specific design for the characteristics of kudzu, such as its high mucilage content, abundant endogenous glycosidases, and layered fibers. Furthermore, the selection of fermentation strains lacks specificity, resulting in kudzu products with weak fat-reducing effects, failing to effectively lower body fat and regulate blood lipid metabolism. Therefore, there is an urgent need to develop a dedicated kudzu pretreatment process, combined with fermentation using fat-reducing probiotics, to prepare a kudzu powder composition with high active ingredient dissolution rates and significant fat-reducing effects, thus meeting the application requirements of functional foods.

[0004] Based on this, the present invention provides a kudzu root powder composition with fat-reducing effect and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a kudzu root powder composition with fat-reducing effects and its preparation method. By designing a kudzu-specific pretreatment process and combining it with the synergistic anaerobic fermentation of *Lactobacillus plantarum* LP-Onlly and *Akermansia muciniphila* AKK016, a kudzu root powder composition is obtained. This preparation process maximizes the release of active ingredients in kudzu root and achieves puerarin aglycone, improving human absorption. Simultaneously, by utilizing the fat-reducing properties of the compound probiotics and the synergistic effect with the active ingredients of kudzu root, it can effectively reduce weight, decrease abdominal fat accumulation, regulate blood lipids and liver fat metabolism, and overall improve the fat-reducing effect of the kudzu root powder composition.

[0006] The technical problems to be solved by this invention are: first, conventional pretreatment processes for kudzu root cannot be adapted to its unique physical properties, resulting in low dissolution rate and poor absorption rate of active ingredients; second, single-strain fermentation has limited effect on improving the fat-reducing efficacy of kudzu root, making it difficult to achieve a synergistic fat-reducing effect between active ingredients and compound probiotics.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing a kudzu root powder composition with fat-reducing effects specifically includes the following steps: S1: Gradually clean and grade kudzu root, pregelatinize it by gradient heating, add enzyme activator to adjust the pH value to 5.5-6, stir at a constant temperature of 40-50℃ for 20-30 minutes, and then perform low-pressure micro-explosion to obtain kudzu root active slurry. After sterilization and optimization, kudzu root fermentation base material is obtained. S2: Prepare a special activation culture medium for kudzu root to activate probiotics and obtain a compound bacterial solution; S3: The compound bacterial solution is inoculated into the kudzu fermentation substrate for synergistic anaerobic fermentation, followed by post-ripening, freeze granulation and drying, and aseptic packaging to obtain the kudzu powder composition.

[0008] Further, in step S1, the specific operation of the graded cleaning is as follows: Select kudzu roots, remove the outer skin and lignified core, retain the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 30-40℃ for 10-15 minutes to dissolve the mucilage on the surface of the kudzu root, then treat with 200-300W low-frequency ultrasound for 3-5 minutes to remove impurities from the fiber gaps, and drain the water.

[0009] Further, in step S1, the specific operation of the gradient temperature pregelatinization is as follows: Add low-mineralized water to the kudzu root, raise the temperature from room temperature to 60-65℃, keep it warm for 15-20 minutes, then raise the temperature to 75-80℃, keep it warm for 10-15 minutes, stop heating, and let it cool naturally to 40-45℃.

[0010] Further, in step S1, by mass, the ratio of kudzu root to low-mineralized water is 1:2, and the mineralization of the low-mineralized water is 40 mg / L.

[0011] Further, in step S1, by mass, kudzu root: enzyme activator = 100: 0.7-0.8.

[0012] Further, in step S1, the enzyme activator is an alcohol-free extract obtained by reflux extraction and concentration of the lignified core of kudzu root with 40% ethanol.

[0013] Furthermore, the specific operation of the low-pressure micro-explosion is as follows: introduce 0.2-0.3MPa sterile air, maintain the pressure for 20-30s, and then release the pressure instantly, repeating 3-4 times.

[0014] Furthermore, the specific operation of the sterilization optimization is as follows: The kudzu root active slurry was brought to a final volume using sterile, low-mineralized water. After maintaining the temperature at 80-90℃ for 3-5 minutes, it was allowed to cool naturally to 40-45℃. Subsequently, the temperature was raised to 80-85℃ and maintained for 3-5 minutes, followed by water bath cooling to 35-40℃. The pH was adjusted to 6-6.5 and the conductivity to 700-800 μS / cm using a lactate-sodium citrate composite buffer solution.

[0015] Furthermore, by weight, the ratio of kudzu root active pulp to sterile low-mineralized water is 1:1.

[0016] Furthermore, in step S2, the kudzu-based activation culture medium is specifically prepared by the following steps: Dilute the kudzu root active slurry 4-5 times with sterile deionized water, and add 0.5-1wt% peptone and 0.3-0.5wt% yeast extract to obtain the kudzu root-based activation culture medium.

[0017] Further, in step S2, the compound probiotic is obtained by mixing *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016, with a volume ratio of 1:1 between *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016 in the compound bacterial solution, and a total viable count ≥ 2 × 10⁻⁶. 9 CFU / mL.

[0018] Further, in step S2, the activation operation specifically includes: Lactobacillus plantarum LP-Onlly and Akkermansia myxophilus AKK016 bacterial powder were inoculated into activation culture medium at a mass ratio of 1:13-15. Lactobacillus plantarum LP-Onlly was aerobically activated at 35-39℃ for 16-20h to obtain activated bacterial solution A. Akkermansia myxophilus AKK016 was anaerobically activated at 35-39℃ for 20-30h to obtain activated bacterial solution B. Activated bacterial solution A and activated bacterial solution B were mixed at a volume ratio of 1:1 to obtain a compound bacterial solution.

[0019] Furthermore, in step S3, the inoculation amount of the compound bacterial solution is 0.3-0.4% of the mass of the kudzu fermentation substrate.

[0020] Furthermore, in step S3, the conditions for the synergistic anaerobic fermentation are: constant temperature fermentation at 35-39℃ for 45-50 hours, the pressure inside the tank is controlled at 0.02MPa for 20-25 hours before fermentation, and then the pressure is released to atmospheric pressure, with no stirring throughout the process.

[0021] Furthermore, in step S3, the post-ripening conditions are: refrigerated at 0-4℃ for 36-48 hours.

[0022] Further, in step S3, the conditions for freeze granulation and drying are as follows: pre-freezing at -40°C to -45°C and vacuum degree of 8-10Pa for 1.5-2 hours, followed by granulation and drying, with a granulation particle size of 0.2-0.3 mm, and drying until the moisture content of the kudzu root powder composition is ≤4%.

[0023] A kudzu root powder composition with fat-reducing effect prepared by the above preparation method.

[0024] The beneficial effects of this invention are: (1) In the technical solution of the present invention, a special pretreatment process for kudzu root is designed. The whole process is based on the unique physical properties of kudzu root, such as high mucilage content, starch gelatinization temperature of 62-78℃, rich endogenous β-glucosidase, and fiber with a layered and dense structure. It has no universality and cannot be adapted to other plants. Moreover, no exogenous enzymes or chemical buffers are added throughout the process. Enzyme activation and pH adjustment are achieved by utilizing the components of kudzu root itself, thus ensuring the naturalness of the kudzu root powder composition.

[0025] (2) In the technical solution of the present invention, the gradient heating pregelatinization and low-pressure layered fiber micro-explosion process can effectively loosen the layered fiber structure of kudzu root and achieve cell wall breaking. Combined with the in-situ activation of endogenous glycosidase, the dissolution rate of puerarin is increased by more than 85%, and more than 90% is converted into puerarin aglycone with stronger fat-reducing activity and higher human absorption rate, thus solving the technical problems of low dissolution rate and poor absorption rate of kudzu root active ingredients.

[0026] (3) In the technical solution of the present invention, Lactobacillus plantarum LP-Onlly and Akkermansia muciniphila AKK016 are used for synergistic anaerobic fermentation. Both strains have been verified by animal experiments to have significant fat reduction effects. The two strains and the active ingredients of kudzu root form a triple fat reduction effect: probiotics regulate the intestinal flora and reduce fat absorption, puerarin aglycone inhibits the synthesis of fatty acids in the liver, and the short-chain fatty acids produced by fermentation synergistically reduce abdominal fat accumulation, which greatly enhances the fat reduction activity of the kudzu root powder composition.

[0027] (4) In the technical solution of the present invention, the pretreatment process and the fermentation process are highly compatible. The pretreatment process provides high-quality base material rich in active ingredients and easily absorbable carbon source for fermentation, ensuring the normal growth and metabolism of probiotics. The fermentation process can further transform the active ingredients of kudzu root to generate fat-reducing metabolites. The resulting kudzu root powder composition has strong stability, high number of live bacteria, no raw fishy smell of kudzu root, and retains the natural aroma of kudzu root. It is suitable for the development and application of functional foods. Detailed Implementation

[0028] 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.

[0029] The specific parameters of the raw materials used in this invention are as follows: Kudzu root (Pueraria lobata), diameter ≥8cm, growth cycle 3-5 years, puerarin content ≥2.5%, commercially available.

[0030] Low-mineralized water, with a mineralization of 40 mg / L.

[0031] Lactobacillus plantarum LP-Onlly: Pronova ® Brand, live bacteria count ≥ 1×10 10 CFU / g; Akkermansia myxophilus AKK016: Pronova ® Brand, live bacteria count ≥ 1×10 10 CFU / g were all provided by Shanghai Jiaotong University Angli Co., Ltd.

[0032] Peptone, food grade, commercially available; yeast extract, food grade, commercially available; citric acid, food grade, commercially available; sodium carbonate, food grade, commercially available.

[0033] Enzyme activator, homemade. The specific preparation method for the enzyme activator is as follows: The lignified core removed during the pretreatment of kudzu root was washed and dried in a 60℃ constant temperature drying oven until constant weight. The dried kudzu root lignified core was then pulverized and passed through a 40-mesh sieve to obtain kudzu root lignified core powder for later use. At a material-to-liquid ratio of 1:10, the kudzu root lignified core powder and 40 vol% food-grade ethanol solution were mixed and transferred to a reflux extraction tank. The mixture was heated to 80℃ and refluxed twice for 2 hours each time. The two extracts were combined to obtain a crude extract of kudzu root lignified core. The crude extract was filtered in a plate and frame filter press to remove the filter residue, resulting in a clear extract of the lignified core of kudzu root. The clear extract was then transferred to a vacuum concentration tank, and the concentration temperature was controlled at 50°C and the vacuum degree at -0.09 MPa. The concentrate was concentrated under reduced pressure until there was no ethanol odor in the concentrate, resulting in a concentrated paste. An equal volume of sterile deionized water was added to the concentrated paste, and the mixture was stirred until completely dissolved. The paste was then filtered through a 0.22 μm sterile filter membrane to remove bacteria, yielding the enzyme activator. This activator was then sealed and refrigerated at 4°C for later use.

[0034] Food-grade lactate-sodium citrate complex buffer solution, homemade. The specific preparation method for the lactate-sodium citrate complex buffer solution is as follows: Mix 85wt% food-grade lactic acid, food-grade sodium citrate, and sterile low-mineralized water at a mass ratio of 1:0.8:20 and stir until completely dissolved to obtain a lactic acid-sodium citrate complex buffer solution. Store in a sealed container at 25°C for later use.

[0035] Example 1 A method for preparing a kudzu root powder composition with fat-reducing effects includes the following steps: S1: Select kudzu root, remove the outer skin and lignified core, retain the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 30℃ for 10 minutes to dissolve the mucilage on the surface of the kudzu root, then treat with 200W low-frequency ultrasound for 3 minutes to remove impurities from the fiber gaps, and drain the water. Take 100 parts by weight of kudzu root extract and add 200 parts by weight of low-mineralized water. Heat the mixture from room temperature to 60°C at a rate of 2°C / min and hold for 15 minutes. Then heat it to 75°C at a rate of 1°C / min and hold for 10 minutes. Stop heating and allow it to cool naturally to 40°C. Add 0.7 parts by weight of enzyme activator and adjust the pH to 5.5. Stir at 40°C for 20 minutes. Purge with 0.2 MPa sterile air and pressurize for 20 seconds, then release the pressure instantly. Repeat this process three times. Pass the mixture through a 100-mesh sieve to obtain kudzu root active slurry. Take 100 parts by weight of kudzu root active slurry and add 100 parts by weight of sterile low-mineralized water to make up the volume. Hold the mixture at 80°C for 3 minutes and allow it to cool naturally to 40°C. Then heat it to 80°C and hold for 3 minutes. Cool it to 35°C in a water bath. Adjust the pH to 6 and the conductivity to 700 μS / cm using a lactic acid-sodium citrate composite buffer solution to obtain kudzu root fermentation substrate.

[0036] S2: Dilute the kudzu root active slurry 4 times with sterile deionized water. Based on the kudzu root active slurry, add 0.5wt% peptone and 0.3wt% yeast extract to prepare a kudzu root-based activation medium. Take *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016 bacterial powder and inoculate them into the activation medium at a mass ratio of 1:13. *Lactobacillus plantarum* LP-Onlly is aerobically activated at 37℃ for 16 hours to obtain activated bacterial solution A. *Ackermania mutans* AKK016 is anaerobically activated at 37℃ for 20 hours to obtain activated bacterial solution B. Mix activated bacterial solution A and activated bacterial solution B at a volume ratio of 1:1 to prepare a composite bacterial solution with a total viable count ≥2×10⁻⁶. 9 CFU / mL.

[0037] S3: Add compound bacterial solution at 0.3% of the mass of kudzu fermentation substrate, stir thoroughly, and then transfer to a static anaerobic fermentation tank. Ferment at a constant temperature of 37℃ for 45 hours. The pressure inside the tank is controlled at 0.02MPa for the first 20 hours of fermentation, and then the pressure is released to atmospheric pressure. The entire process is static and without stirring. After fermentation, the material is placed in a 0℃ refrigerator for 36 hours for post-maturation, and then transferred to a vacuum freeze granulator. It is pre-frozen at -40℃ and a vacuum degree of 8Pa for 1.5 hours, then granulated and dried to a particle size of 0.2mm. The moisture content of the kudzu powder composition is ≤4%. Finally, it is passed through a 100-mesh sieve in a sterile environment, sealed in a nitrogen-filled aluminum foil bag, and the kudzu powder composition is obtained.

[0038] Example 2 A method for preparing a kudzu root powder composition with fat-reducing effects includes the following steps: S1: Select kudzu root, remove the outer skin and lignified core, retain the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 35℃ for 12 minutes to dissolve the mucilage on the surface of the kudzu root, then treat with 250W low-frequency ultrasound for 4 minutes to remove impurities from the fiber gaps, and drain the water. By weight, 100 parts of kudzu root extract were added to 200 parts of low-mineralized water. The temperature was increased from room temperature to 63°C at 2°C / min and held for 18 minutes. Then, the temperature was increased to 78°C at 1°C / min and held for 12 minutes. Heating was stopped, and the temperature was allowed to drop naturally to 43°C. 0.75 parts of enzyme activator were added, and the pH was adjusted to 5.8. The mixture was stirred at 45°C for 25 minutes. Stress was applied by introducing 0.25 MPa of sterile air and holding for 25 seconds, followed by instantaneous depressurization. This process was repeated three times. The mixture was then passed through a 100-mesh sieve to obtain kudzu root active slurry. By weight, 100 parts of kudzu root active slurry were added to 100 parts of sterile low-mineralized water and brought to a final volume. The mixture was held at 85°C for 4 minutes and then allowed to cool naturally to 42°C. The temperature was then increased to 83°C and held for 4 minutes. The mixture was then cooled to 38°C in a water bath. The pH was adjusted to 6.3 and the conductivity to 750 μS / cm using a lactic acid-sodium citrate composite buffer solution to obtain the kudzu root fermentation substrate.

[0039] S2: Dilute the kudzu root active slurry 4.5 times with sterile deionized water. Based on the kudzu root active slurry, add 0.8 wt% peptone and 0.4 wt% yeast extract to prepare a kudzu root-based activation medium. Take *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016 bacterial powder and inoculate them into the activation medium at a mass ratio of 1:14. *Lactobacillus plantarum* LP-Onlly is aerobically activated at 37℃ for 18 hours to obtain activated bacterial solution A. *Ackermania mutans* AKK016 is anaerobically activated at 37℃ for 25 hours to obtain activated bacterial solution B. Mix activated bacterial solution A and activated bacterial solution B at a volume ratio of 1:1 to prepare a composite bacterial solution with a total viable count ≥2×10⁻⁶. 9 CFU / mL.

[0040] S3: Inoculate the compound bacterial solution at 0.35% of the mass of the kudzu fermentation substrate, stir thoroughly, and then transfer to a static anaerobic fermentation tank. Ferment at a constant temperature of 37℃ for 48 hours. The pressure inside the tank is controlled at 0.02MPa for the first 23 hours of fermentation, and then the pressure is released to atmospheric pressure. The entire process is static and without stirring. After fermentation, the material is placed in a 2℃ refrigerator for 42 hours for post-maturation, and then transferred to a vacuum freeze granulator. It is pre-frozen at -43℃ and a vacuum degree of 9Pa for 1.8 hours, then granulated and dried to a particle size of 0.25mm. The moisture content of the kudzu powder composition is ≤4%. Finally, it is passed through a 100-mesh sieve in a sterile environment, sealed in a nitrogen-filled aluminum foil bag, and the kudzu powder composition is obtained.

[0041] Example 3 A method for preparing a kudzu root powder composition with fat-reducing effects includes the following steps: S1: Select kudzu root, remove the outer skin and lignified core, retaining the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 40℃ for 15 minutes to dissolve the mucilage on the surface of the kudzu root, then treat with 300W low-frequency ultrasound for 5 minutes to remove impurities from the fiber gaps, and drain the water; take 100 parts by weight of kudzu root cubes, add 200 parts of low-mineralized water, heat from room temperature to 65℃ at 2℃ / min, hold at this temperature for 20 minutes, then heat to 80℃ at 1℃ / min, hold at this temperature for 15 minutes, stop heating, and allow to cool naturally to 45℃. Add 0.8 parts of enzyme activator, adjust the pH to 6, and stir at 50℃ for 30 min. Then, pressurize with 0.3 MPa sterile air for 30 s and release the pressure instantly. Repeat this process 4 times. Pass the mixture through a 100-mesh sieve to obtain kudzu root active slurry. Take 100 parts of kudzu root active slurry by weight, add 100 parts of sterile low-mineralized water to make up the volume, keep at 90℃ for 5 min, and then cool naturally to 45℃. Then, raise the temperature to 85℃ and keep it for 5 min, and cool it to 40℃ in a water bath. Adjust the pH to 6.5 and the conductivity to 800 μS / cm with lactic acid-sodium citrate composite buffer to obtain kudzu root fermentation substrate.

[0042] S2: Dilute the kudzu root active slurry 5 times with sterile deionized water. Based on the kudzu root active slurry, add 1 wt% peptone and 0.5 wt% yeast extract to prepare a kudzu root-based activation medium. Take *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016 bacterial powder and inoculate them into the activation medium at a mass ratio of 1:15. *Lactobacillus plantarum* LP-Onlly is aerobically activated at 37℃ for 20 h to obtain activated bacterial solution A. *Ackermania mutans* AKK016 is anaerobically activated at 37℃ for 30 h to obtain activated bacterial solution B. Mix activated bacterial solution A and activated bacterial solution B at a volume ratio of 1:1 to prepare a composite bacterial solution with a total viable count ≥2×10⁻⁶. 9 CFU / mL.

[0043] S3: Inoculate the compound bacterial solution at 0.4% of the weight of the kudzu fermentation substrate, stir thoroughly, and then transfer to a static anaerobic fermentation tank. Ferment at a constant temperature of 37℃ for 50 hours. The pressure inside the tank is controlled at 0.02MPa for the first 25 hours of fermentation, and then the pressure is released to atmospheric pressure. The entire process is static and unstirred. After fermentation, the material is refrigerated at 4℃ for 48 hours for post-maturation, then transferred to a vacuum freeze granulator. Under conditions of -45℃ and a vacuum degree of 10Pa, it is pre-frozen for 2 hours, then granulated and dried to a particle size of 0.3mm. The moisture content of the kudzu powder composition is dried to ≤4%. Finally, it is passed through a 100-mesh sieve in a sterile environment, sealed in a nitrogen-filled aluminum foil bag, and the kudzu powder composition is obtained.

[0044] Comparative Example 1 The difference between this comparative example and Example 3 is that in step S1, the gradient heating pregelatinization and low-pressure micro-explosion operation are cancelled, while the remaining steps and raw materials are the same as in Example 3.

[0045] The specific steps are as follows: Selected kudzu roots, remove the outer skin and lignified core, retaining the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 40℃ for 15min to dissolve the mucilage on the surface of the kudzu root, then treat with 300W low-frequency ultrasound for 5min to remove impurities from the fiber gaps, and drain the water; take 100 parts by weight of kudzu root cubes, add 200 parts by weight of purified water, stir at 25℃ until the kudzu root cubes are evenly dispersed, add 0.8 parts by weight of enzyme activator, adjust the pH value to 6, stir at 50℃ for 30min, and pass through a 100-mesh sieve to obtain kudzu root pulp; take 100 parts by weight of kudzu root pulp, add 100 parts by weight of sterile purified water to make up the volume, keep at 90℃ for 5min, then cool naturally to 45℃, then raise the temperature to 85℃ and keep for 5min, and cool in a water bath to 40℃; adjust the pH value to 6.5 and the conductivity to 800μS / cm with lactate-sodium citrate composite buffer to obtain kudzu root base material. The subsequent steps S2 and S3 are the same as in Example 3.

[0046] Comparative Example 2 The difference between this comparative example and Example 3 is that in step S1, the amount of enzyme activator added is 0.5 parts, the pH value is adjusted to 5.0, and the mixture is stirred at a constant temperature of 40°C for 15 minutes. The remaining steps and raw materials are the same as in Example 3.

[0047] Comparative Example 3 The difference between this comparative example and Example 3 is that in step S2, only *Lactobacillus plantarum* LP-Onlly was used as the compound probiotic, without the addition of *Ackermania ulmoides* AKK016; *Lactobacillus plantarum* LP-Onlly was inoculated into the activation medium at a mass ratio of 1:15, and *Lactobacillus plantarum* LP-Onlly was aerobically activated at 37°C for 20 hours to obtain the activated bacterial solution; the inoculation amount of the activated bacterial solution was 0.4% of the mass of the kudzu root fermentation substrate, and the remaining steps and raw materials were consistent with those in Example 3.

[0048] Comparative Example 4 The difference between this comparative example and Example 3 is that in step S3, the temperature of the synergistic anaerobic fermentation is 30°C, the constant temperature fermentation is 30h, and the pressure inside the tank is controlled at 0.02MPa for 15h before fermentation. The remaining steps and raw materials are the same as in Example 3.

[0049] Comparative Example 5 The difference between this comparative example and Example 3 is that, in step S3, hot air drying is used instead of freeze granulation drying, the drying temperature is 60°C, and the kudzu root powder composition is dried until the moisture content is ≤4%. The remaining steps and raw materials are the same as in Example 3.

[0050] The active ingredient content and fat-reducing effect of the kudzu root powder compositions prepared in Examples 1-3 and Comparative Examples 1-5 were tested in animal experiments. The test methods followed the C57BL / 6J mouse hyperlipidemia model and strictly adhered to relevant testing standards. The data were statistically analyzed using IBM SPSS Statistics 30.0. Quantitative data are presented as follows: The comparisons between groups were performed using one-way ANOVA, with P < 0.05 considered statistically significant and P < 0.01 considered highly statistically significant. The specific testing methods and results are shown below: The active ingredient content of the kudzu root powder composition samples obtained in Examples 1-3 and Comparative Examples 1-5 was detected. The content of puerarin aglycone was detected by high performance liquid chromatography, the number of viable bacteria in the finished product was detected by plate counting method, and the moisture content was detected by direct drying method. The test results of each experimental group are shown in Table 1.

[0051] Table 1 Results of Active Ingredient Content Detection

[0052] The fat-reducing effects of the kudzu root powder compositions obtained in Examples 1-3 and Comparative Examples 1-5 were tested; the specific test methods are as follows: SPF-grade male C57BL / 6J mice, weighing 18-20g, were selected and, after 3 days of acclimatization, were randomly divided into a negative control group (normal diet) and a high-fat model group (60% fat-based purified diet for energy). The mice were fed for 8 weeks, and the successful modeling was defined as the mice in the high-fat model group having a body weight that was 20% higher than that in the negative control group.

[0053] Mice that successfully developed the model were randomly divided into a model control group (gavaged with pure water), Example 1-3 groups, and Comparative Example 1-5 groups, with 8 mice in each group. Each test group was gavaged with the corresponding kudzu root powder suspension at a dose of 195 mg / kg / day. The negative control group and the model control group were gavaged with an equal volume of pure water. The gavage was continued for 36 days. During this period, the high-fat diet group was continuously fed a high-fat diet with free access to food and water. The gavage dose was adjusted weekly according to the weight of the mice. After the experiment, the weight loss rate, Lee's index, inguinal fat weight loss rate, serum low-density lipoprotein cholesterol (LDL-C) reduction, and liver fatty acid synthase (FAS) reduction were measured. The change rate / significance of each indicator compared with the model control group was used as the evaluation criterion. The results are shown in Table 2.

[0054] Table 2 Results of fat reduction effect test

[0055] As shown in Tables 1 and 2, the puerarin aglycone content of the kudzu root powder compositions prepared in Examples 1-3 is ≥1.8%, and the viable bacteria count of the finished product is ≥5.8×10⁻⁶. 8The CFU / g and moisture content were all ≤3.7%, and the indicators of various active ingredients were excellent. It significantly reduced the body weight, Lee's index and groin fat weight of high-fat model mice, and also significantly reduced serum LDL-C and liver FAS levels, showing outstanding fat reduction effect. Moreover, Example 2 is the optimal ratio of each parameter, with the highest content of active ingredients and fat reduction effect among all groups.

[0056] The results in Comparative Example 1 show that when the gradient heating pregelatinization and low-pressure micro-explosion operations were cancelled, the cell structure of kudzu root was not effectively destroyed, the dissolution rate of puerarin aglycones decreased significantly, the number of viable bacteria was also reduced due to the influence of substrate quality, and there were no significant differences in various fat reduction indicators compared with the model control group.

[0057] The results from Comparative Example 2 show that insufficient addition of enzyme activator and deviations of pH and stirring time from the optimal range resulted in inadequate activation of endogenous glycosidases in puerarin, reduced conversion efficiency of puerarin to aglycones, decreased viable bacteria count and fat reduction index levels, leading to a decline in the effectiveness of the composition.

[0058] The results of Comparative Example 3 show that using only Lactobacillus plantarum for fermentation lacks the synergistic fat-reducing effect of Akkermansia muciniphila, and the nutritional complementarity between bacterial species disappears. The number of live bacteria in the finished product is significantly reduced, and the fat-reducing index level also decreases. This indicates that the combination of compound probiotics is the key to achieving efficient fat reduction.

[0059] The results of Comparative Example 4 show that when the fermentation temperature is too low and the time is too short, the probiotics do not complete sufficient growth and metabolism, the number of live bacteria decreases significantly, and the production of fat-reducing active substances in the fermentation products is insufficient. There are no significant differences between the various fat-reducing indicators and the model control group, indicating that the temperature, humidity and time parameters of anaerobic fermentation directly affect the fermentation effect.

[0060] The results of Comparative Example 5 show that when hot air drying was used instead of freeze granulation drying, the high temperature caused a large number of probiotics to become inactive, and puerarin aglycone also underwent partial thermal degradation. The active ingredients and the number of live bacteria were reduced to the lowest in all groups, resulting in poor fat reduction effect.

[0061] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a kudzu root powder composition with fat-reducing effects, characterized in that, Includes the following steps: S1: Gradually clean and grade kudzu root, pregelatinize it by gradient heating, add enzyme activator to adjust the pH value to 5.5-6, stir at a constant temperature of 40-50℃ for 20-30 minutes, and then perform low-pressure micro-explosion to obtain kudzu root active slurry. After sterilization and optimization, kudzu root fermentation base material is obtained. S2: Prepare a special activation culture medium for kudzu root to activate probiotics and obtain a compound bacterial solution; S3: The compound bacterial solution is inoculated into the kudzu fermentation substrate for synergistic anaerobic fermentation, followed by post-ripening, freeze granulation and drying, and aseptic packaging to obtain the kudzu powder composition.

2. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S1, the specific operation of the graded cleaning is as follows: Select kudzu roots, remove the outer skin and lignified core, retaining the fleshy phloem, and cut into 1cm kudzu root cubes; soak in 0.1wt% edible citric acid solution at 30-40℃ for 10-15 minutes to dissolve the mucilage on the surface of the kudzu root, then treat with 200-300W low-frequency ultrasound for 3-5 minutes to remove impurities from the fiber gaps, and drain the water.

3. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S1, the specific operation of gradient temperature pregelatinization is as follows: Add low-mineralized water to the kudzu root, raise the temperature from room temperature to 60-65℃, keep it warm for 15-20 minutes, then raise the temperature to 75-80℃, keep it warm for 10-15 minutes, stop heating, and let it cool naturally to 40-45℃.

4. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S1, the specific operation of the low-pressure micro-explosion is as follows: introduce 0.2-0.3MPa sterile air, maintain the pressure for 20-30s, and then release the pressure instantly. Repeat the operation 3-4 times.

5. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, The specific steps for sterilization optimization are as follows: The kudzu root active slurry was brought to a final volume using sterile, low-mineralized water. After maintaining the temperature at 80-90℃ for 3-5 minutes, it was allowed to cool naturally to 40-45℃. Subsequently, the temperature was raised to 80-85℃ and maintained for 3-5 minutes, followed by water bath cooling to 35-40℃. The pH was adjusted to 6-6.5 and the conductivity to 700-800 μS / cm using a lactate-sodium citrate composite buffer solution.

6. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S2, the kudzu-based activation culture medium is prepared through the following steps: Dilute the kudzu root active slurry 4-5 times with sterile deionized water, and add 0.5-1wt% peptone and 0.3-0.5wt% yeast extract to obtain the kudzu root-based activation culture medium.

7. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S2, the compound probiotic is obtained by mixing *Lactobacillus plantarum* LP-Onlly and *Ackermania mutans* AKK016; the volume ratio of *Lactobacillus plantarum* LP-Onlly to *Ackermania mutans* AKK016 in the compound bacterial solution is 1:1, and the total viable count is ≥2×10⁻⁶. 9 CFU / mL.

8. The method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S2, the activation operation specifically includes: Lactobacillus plantarum LP-Onlly and Akkermansia myxophilus AKK016 were inoculated into activation medium at a mass ratio of 1:13-15. Lactobacillus plantarum LP-Onlly was aerobically activated at 35-39℃ for 16-20h to obtain activated bacterial solution A. Akkermansia myxophilus AKK016 was anaerobically activated at 35-39℃ for 20-30h to obtain activated bacterial solution B. Activated bacterial solution A and activated bacterial solution B were mixed at a volume ratio of 1:1 to obtain a compound bacterial solution.

9. A method for preparing a kudzu root powder composition with fat-reducing effect according to claim 1, characterized in that, In step S3, the conditions for the synergistic anaerobic fermentation are: constant temperature fermentation at 35-39℃ for 45-50 hours, the pressure inside the tank is controlled at 0.02MPa for 20-25 hours before fermentation, and then the pressure is released to atmospheric pressure, with no stirring throughout the process.

10. A kudzu root powder composition with fat-reducing effect prepared by the preparation method according to any one of claims 1-9.

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