Pueraria powder, and preparation method and application thereof

Abstract

This invention discloses a kudzu root powder, its preparation method, and its applications, relating to the field of kudzu root development and utilization technology. The preparation method of the kudzu root powder of this invention includes the following steps: obtaining raw kudzu root powder; adding an acidifying agent to a pre-spraying solution with a pH of 3-7 to prepare an acidified aqueous solution; uniformly spraying the acidified aqueous solution onto the kudzu root powder; mixing the acidified aqueous solution with the kudzu root powder until the moisture content of the wet kudzu root powder is 20-30%; placing the wet kudzu root powder in a sealed environment for equilibration; after equilibration, pre-drying the resulting material until the moisture content is 5-15%; heating the pre-dried material and then cooling it to room temperature, followed by pulverizing to obtain baked kudzu root powder. This method adopts a main route combining a small amount of acidified water for humidification with heat modification of low-moisture powder, effectively reducing core processes, significantly lowering water consumption and energy consumption, and virtually eliminating waste liquid discharge. It has the advantages of simplified process, low equipment requirements, and ease of large-scale production in the food industry.

Description

Technical Field

[0001] This invention relates to the field of kudzu development and utilization technology, and in particular to a kudzu powder, its preparation method and application. Background Technology

[0002] High-calorie diets and sedentary lifestyles have led to a year-on-year increase in the incidence of metabolic syndrome, including obesity, hyperglycemia, and hyperlipidemia, which has become a global public health problem. People are paying increasing attention to preventing and improving these health problems through daily diet. Therefore, functional foods (i.e., foods that provide additional health benefits in addition to basic nutrition) have become a hot topic in research and development.

[0003] Resistant starch is a very important functional food ingredient. Simply put, resistant starch is a type of starch that is "difficult to digest." Unlike regular starch, it cannot be digested and absorbed in the small intestine and will not be converted into glucose to raise blood sugar levels. It directly enters the large intestine, where it is fermented by gut microbiota, producing beneficial substances such as short-chain fatty acids. This allows it to perform various physiological functions, including regulating gut microbiota, improving glucose and lipid metabolism, and increasing satiety. Therefore, developing foods rich in resistant starch is of great significance for the prevention and control of chronic diseases such as obesity and diabetes.

[0004] Kudzu root is both a commonly used traditional Chinese medicine and a food ingredient with medicinal properties. Its starch (i.e., kudzu root powder) is not only high in starch but also naturally contains active ingredients such as kudzu flavonoids, which have potential benefits in lowering blood lipids and blood pressure. Therefore, using kudzu root to prepare resistant starch has the potential to yield products with the dual benefits of starch properties and flavonoid activity, showing great promise.

[0005] Existing methods for preparing resistant starch from kudzu root often employ wet processes. Current reported wet processes, such as acid hydrolysis and enzymatic hydrolysis (e.g., pullulanase) debranching, typically require large amounts of aqueous solutions. These methods are often cumbersome, involving multiple steps including slurry preparation, gelatinization, enzymatic hydrolysis, enzyme inactivation, washing, and drying. They are energy-intensive, place significant pressure on wastewater treatment, and may cause the loss of water-soluble active ingredients such as flavonoids. Furthermore, while existing technologies using chemical or enzymatic treatments can significantly increase the content of resistant starch, they may destroy the natural functional factors such as kudzu flavonoids inherent in kudzu root. This type of process often emphasizes resistant starch content while neglecting the retention of natural components.

[0006] Specifically, Chinese patent (publication number CN106213518A) discloses a method for preparing resistant starch from kudzu root, which includes the following steps: (1) Mix kudzu starch and water in a mass ratio of 1: (1~3), and ultrasonically mix to obtain starch paste.

[0007] (2) Add acid to the starch paste obtained in step (1), adjust the pH value of the starch paste to 2~5, control the temperature to 50~80℃, and let it stand for 4~10h to obtain acidified liquid.

[0008] (3) Heat the acidified liquid obtained in step (2) to 100~150℃ and stir it under normal pressure for 2~5 hours to obtain the reaction solution.

[0009] (4) Cool the reaction solution obtained in step (3) to 20~30℃, adjust the pH of the reaction solution to 3.8~7.0 with alkali, and obtain liquid product.

[0010] (5) The liquid product obtained in step (4) is dried and pulverized to obtain kudzu resistant starch.

[0011] This process is a typical wet acid-thermal route, using kudzu starch as raw material. First, water is added to obtain a high-water-content starch paste, which is then subjected to ultrasonic slurry preparation, high-temperature stirring in an acidifying solution, cooling and neutralization, and freeze-drying to obtain kudzu resistant starch. This process is not only cumbersome, but also requires a large amount of acid and alkali solutions for subsequent pH adjustment due to the need to add a large amount of water, and the energy consumption during drying is also high. Summary of the Invention

[0012] This invention discloses a kudzu root powder, its preparation method, and its application, in order to solve the technical problems of the preparation method of kudzu root resistant starch in related technologies, which involves complicated steps, large amounts of acid and alkali solutions required for pH adjustment, and high energy consumption during drying.

[0013] To solve the above problems, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for preparing kudzu root powder.

[0014] The method for preparing kudzu root powder according to the present invention includes the following steps: Step 100: Obtain the raw material kudzu root powder; Step 200: Add an acidifying agent to the pre-spraying solution with a pH value of 3-7 to prepare an acidified aqueous solution. Spray the acidified aqueous solution evenly onto the kudzu root powder. After mixing the acidified aqueous solution with the kudzu root powder, the moisture content of the wet kudzu root powder is 20-30%. Step 300: Place the wet kudzu root powder material in a sealed environment to equilibrate; Step 400: After equilibration, pre-dry the material obtained in step 300 until the moisture content is 5-15%; Step 500: After heating the material obtained in step 400, cool it to room temperature and then pulverize it to obtain roasted kudzu root powder.

[0015] According to an optional embodiment, after obtaining the raw kudzu root powder in step 100, the method further includes recording the moisture content of the kudzu root powder. Preferably, the moisture content of the kudzu root powder is less than 10%.

[0016] According to an optional implementation, in step 100, the raw material kudzu root powder is one or more of the following: whole kudzu root powder, kudzu root starch, a blend of kudzu root powder and whole grain powder, a blend of kudzu root powder and bean powder, and a blend of kudzu root powder and dietary fiber.

[0017] According to an optional embodiment, in step 200, the acidifying agent is at least one selected from citric acid, lactic acid, malic acid, tartaric acid, acetic acid, gluconic acid, hydrochloric acid, and phosphoric acid; the amount of acidifying agent added is 1% of the dry weight of the raw kudzu root powder; and / or, in step 200, the pre-spraying solution with a pH value of 3-7 is deionized water or hydrochloric acid solution; and / or, in step 200, the acidified aqueous solution is uniformly sprayed onto the kudzu root powder by one or more of the following methods: spraying, vacuum mixing, and fluidized bed humidification. According to an optional embodiment, in step 300, the temperature of the sealed environment is 15-30°C; and / or, the wet kudzu root powder material is placed in the sealed environment for equilibration for 2-14 hours.

[0018] According to an optional implementation, in step 400, the material obtained in step 300 is spread out, wherein the thickness of the spread material layer is 0.5~3.0cm; the pre-drying temperature is 50~100℃; and / or, in step 400, the material obtained in step 300 is pre-dried by introducing one or more of the following methods: hot air, vacuum, infrared, microwave, fluidized bed heating.

[0019] According to an optional implementation, in step 500, the material obtained in step 400 is heated at 130~150℃ for 3~8 hours; and / or, in step 500, the material obtained in step 400 is heated using one or more of the following methods: oven, hot air furnace, drum, fluidized bed, infrared, microwave, continuous belt equipment; and / or, in step 500, when heating the material obtained in step 400, a single constant temperature, multi-stage heating or pulse heating method is used to heat the material obtained in step 400.

[0020] According to an optional embodiment, in step 500, the material that has been heated and cooled to room temperature is pulverized and then passed through a 60-120 mesh sieve to obtain roasted kudzu root powder; and / or, in step 500, the material that has been heated and cooled to room temperature is pulverized using one or more of the following methods: grinding, air jet milling, ball milling, cryogenic pulverization, and extrusion.

[0021] A second aspect of the present invention discloses a kudzu root powder.

[0022] The kudzu root powder of the present invention is roasted kudzu root powder obtained by the preparation method of kudzu root powder described in any one of the technical solutions of the present invention.

[0023] The third aspect of the present invention discloses an application of kudzu root powder.

[0024] The application of kudzu root powder according to any one of the technical solutions of this invention in the preparation of anti-obesity foods, foods that assist in weight management, foods that improve glucose and lipid metabolism, foods that reduce intestinal lipid absorption, and / or foods that improve intestinal flora.

[0025] According to one optional embodiment, the food is one or more of the following: instant powder, meal replacement powder, baked food, cereal product, convenience food, nutrition bar, or compound powder. When the food is instant powder and / or meal replacement powder, the content of roasted kudzu root powder is 10-80%; when the food is baked food, the content of roasted kudzu root powder is 5-40%; when the food is cereal product and / or nutrition bar, the content of roasted kudzu root powder is 3-60%; and when the food is convenience food and / or compound powder, the content of roasted kudzu root powder is 1-15%.

[0026] The technical solution adopted in this invention can achieve the following beneficial effects: Firstly, the method for preparing kudzu root powder of the present invention abandons the high water content starch paste system and adopts the main route of adjusting the moisture content with a small amount of acidified water combined with the heat modification of low moisture powder. It does not require enzyme debranching, multiple freezing cycles or extraction and purification as necessary steps, nor does it require ultrasonic slurry preparation, alkali neutralization and high energy consumption vacuum freeze drying. The core process is effectively reduced, water consumption and energy consumption are greatly reduced, and there is basically no waste liquid discharge. It has the outstanding advantages of simplified process, low equipment requirements and easy large-scale production in the food industry.

[0027] Secondly, the method for preparing kudzu root powder of this invention, through systematic characterization methods such as X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and chain length distribution, confirms that the roasted kudzu root powder undergoes a clear, multi-level structural change compared to the raw kudzu root powder. Specifically, the relative crystallinity of the roasted kudzu root powder increases from 28.75±3.35% in the raw material to 37.38±0.52%; the 1047 / 1022 cm⁻¹, representing short-range order in the Fourier transform infrared spectrum... -1 The ratio increased from 0.907±0.003 to 0.912±0.006, representing 995 / 1022 cm⁻¹ of the double helix's degree of order. -1The ratio increased from 0.955±0.002 to 0.999±0.004. Differential scanning calorimetry (DSC) showed that the enthalpy of thermal transition (ΔH) decreased from 11.98±0.30 J / g in the raw material to 9.29±0.16 J / g, and the onset temperature (To), peak temperature (Tp), and termination temperature (Tc) shifted from 64.9℃, 71.2℃, and 82.5℃ to 59.4℃, 65.8℃, and 74.1℃, respectively. Scanning electron microscopy (SEM) images also showed a distinct modified rough morphology on the particle surface. Chain length distribution analysis showed that the number of chain length peaks decreased from three in the raw material to two, indicating that the resistant starch preparation process significantly altered the chain length composition of starch molecules, reducing high molecular weight or long-chain components while relatively enriching medium-length components. This change suggests that the treatment process may promote the degradation, rearrangement, and formation of ordered structures in starch chains, thereby facilitating the formation of resistant starch structures. Meanwhile, the in vitro digestibility characteristics changed significantly. The proportion of rapidly digestible starch (RDS) in the sample decreased from 67.7±1.8% in the raw material to 41.8±2.9%, the proportion of slowly digestible starch (SDS) decreased from 23.3±4.1% to 16.8±2.4%, while the proportion of resistant starch (RS) increased significantly from 8.9±3.7% to 41.4±1.6%.

[0028] Thirdly, the method for preparing kudzu root powder of the present invention yields roasted kudzu root powder with a total dietary fiber content as high as 18.46%, which is a significant increase compared to the 3.69% of the raw kudzu root powder. At the same time, the content of the characteristic component puerarin is increased to 69 mg / 100 g, indicating that the method for preparing kudzu root powder of the present invention effectively retains the natural accompanying functional components of whole kudzu root powder while increasing the proportion of resistant starch, thus possessing a high-quality raw material basis as a kudzu root composite functional powder.

[0029] Fourthly, the method for preparing kudzu root powder of this invention allows the roasted kudzu root powder to be used in the preparation of anti-obesity foods, foods to assist in weight management, foods to improve glucose and lipid metabolism, foods to reduce intestinal lipid absorption, and / or foods to improve gut microbiota. Under conditions where there was no significant difference in food intake, the roasted kudzu root powder intervention group significantly improved weight gain, reduced the proportion of adipose tissue accumulation, and increased the proportion of lean body mass. At the level of glucose and lipid metabolism, it significantly reduced fasting blood glucose, fasting insulin, and insulin resistance index, and improved oral glucose tolerance and insulin tolerance. At the tissue level, it reduced hepatic lipid deposition and lowered serum triglyceride, free fatty acid, total cholesterol, and low-density lipoprotein cholesterol levels. At the inflammatory level, serum endotoxin and inflammatory factors such as tumor necrosis factor-α, interleukin-1β, and interleukin-6 were significantly reduced. Most importantly, oral fat tolerance tests and intestinal tissue analysis confirmed that roasted kudzu root powder can effectively inhibit postprandial lipid absorption, downregulate the expression of genes related to intestinal fatty acid uptake (CD36, FATP4), triglyceride resynthesis (MOGAT2), and chylomicron packaging and transport (MTTP, APOA4), and significantly improve high-fat diet-induced gut microbiota dysbiosis (increase Chao index and decrease F / B ratio). Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is the XRD pattern of the roasted kudzu root powder and the raw kudzu root powder of this application; Figure 2 These are the FTIR spectra of roasted kudzu root powder and raw kudzu root powder of this application; Figure 3 These are SEM images of the roasted kudzu root powder and the raw kudzu root powder of this application; Figure 4 This is a DSC curve of the roasted kudzu root powder and the raw kudzu root powder of this application; Figure 5 This is a chain length distribution diagram of the roasted kudzu root powder and the raw kudzu root powder of this application; Figure 6 A is an experimental flowchart of the embodiments of this application, in which mice were modeled and fed for 12 weeks, followed by 8 weeks of intervention, and sacrificed for analysis at week 20. Figure 6 B is a graph showing the change in body weight of mice in each group during 8 intervention cycles in the embodiments of this application; Figure 6C is a graph showing the weight gain of mice in each group after 8 weeks of intervention in the embodiments of this application; Figure 6 D is a graph showing the composition of body components (including fat mass, lean body mass, and free fluid) of mice in each group according to the embodiments of this application; Figure 6 E is a schematic diagram showing the proportion of total adipose tissue weight to body weight in each group of mice in the embodiments of this application; Figure 6 F is a schematic diagram showing the proportion of weight of different adipose tissues (including iWAT, pWAT, mWAT, sWAT and BAT) to body weight in each group of mice in the embodiments of this application. Figure 6 G is a graph showing the changes in fasting blood glucose in mice during the intervention period in each group of mice in the embodiments of this application; Figure 6 H is a graph showing the fasting blood glucose levels of mice in each group in the embodiments of this application; Figure 6 I is a graph showing the fasting insulin levels of mice in each group according to the embodiments of this application; Figure 6 J is the HOMA-IR graph of the insulin resistance index of mice in each group of embodiments of this application; Figure 6 K is a graph showing the changes in blood glucose during the oral glucose tolerance test (OGTT) in mice in each group of the embodiments of this application. Figure 6 L is a schematic diagram of the area under the OGTT curves of each group of mice in the embodiments of this application; Figure 6 M is a graph showing the changes in blood glucose during the insulin tolerance test (ITT) in each group of mice according to the embodiments of this application. Figure 6 N is a schematic diagram of the area under the ITT curve of each group of mice in the embodiments of this application; Figure 6 O is a graph showing the serum LPS levels of mice in each group in the embodiments of this application; Figure 6 Q is a graph showing the serum IL-1β levels of mice in each group according to the embodiments of this application; Figure 6 R is a graph showing the serum IL-6 levels of mice in each group according to the embodiments of this application; Figure 7 A is a graph showing the serum triglyceride (TG) levels of mice in each group according to the embodiments of this application; Figure 7 B is a graph showing the serum free fatty acid (FFA) levels of mice in each group according to the embodiments of this application; Figure 7 C is a graph showing the serum total cholesterol (TC) levels of mice in each group according to the embodiments of this application; Figure 7 D is a graph showing the serum low-density lipoprotein cholesterol (LDL-C) levels of mice in each group of the embodiments of this application. Figure 7 E is a graph showing the HE staining results of mouse livers in each group of embodiments of this application (used to observe liver tissue morphology and fatty degeneration); Figure 7 F is a graph showing the results of Oil Red O staining of mouse livers in each group of embodiments of this application (used to observe liver lipid deposition); Figure 7 G is a quantitative analysis graph of the area of ​​Oil Red O positive in the liver of mice in each group of embodiments of this application; Figure 7 H is a graph showing the triglyceride (TG) content in the livers of mice in each group of embodiments of this application; Figure 8 A is a graph showing the changes in serum TG levels during the fat tolerance test (FTT) in each group of mice according to the embodiments of this application. Figure 8 B is a schematic diagram of the area under the serum TG curve during the FTT in each group of mice in the embodiments of this application; Figure 8 C is a graph showing the changes in serum FFA levels in mice during the FTT in each group of mice in the embodiments of this application; Figure 8 D is a schematic diagram of the area under the serum FFA curve during the FTT in each group of mice in the embodiments of this application; Figure 8 E is a graph showing the results of Oil Red O staining of the ileum of mice in each group of embodiments of this application (used to observe intestinal lipid absorption and deposition); Figure 8 F is a quantitative analysis graph of the area of ​​Oil Red O positive in the ileum of mice in each group of embodiments of this application; Figure 8 G is a graph showing the TG content in the ileum of mice in each group of embodiments of this application; Figure 8 H is a graph showing the TG content in the feces of mice in each group of embodiments of this application; Figure 8 I is a graph showing the mRNA expression levels of the genes CD36, FATP4, FABP1, and FABP2 related to fatty acid uptake in the ileum of mice in each group of the embodiments of this application. Figure 8 J is a graph showing the mRNA expression levels of SRB1 and NPC1L1, genes related to cholesterol uptake in the ileum of mice in each group of the embodiments of this application. Figure 8 K is a graph showing the mRNA expression levels of genes related to the resynthesis of ileal triglycerides, namely ACAT2, MOGAT2, DGAT1, and DGAT2, in each group of mice in the embodiments of this application. Figure 8 L is a graph showing the mRNA expression levels of MTTP, APOA4, and APOB, genes related to ileal chylomicron packaging and transport in each group of mice in the embodiments of this application. Figure 9 A is a Shannon index diagram of the α-diversity of intestinal flora in mice in each group of embodiments of this application; Figure 9 B is a Chao index diagram showing the richness of intestinal flora in mice in each group of embodiments of this application; Figure 9 C is the Simpson index diagram of the α-diversity of the intestinal flora of mice in each group of embodiments of this application; Figure 9 D is a graph showing the PCoA analysis results of the β diversity of the intestinal flora in each group of mice in the embodiments of this application; Figure 9 E is a graph showing the NMDS analysis results of the β diversity of the intestinal flora of mice in each group of embodiments of this application; Figure 9 F is a heatmap of the relative abundance of gut microbiota at the phylum level in each group of mice in the embodiments of this application; Figure 9 G represents the F / B ratio of the intestinal flora of mice in each group of embodiments of this application; Figure 9 H is the LEfSe phylogenetic branch diagram of the differential bacterial communities between the HFD group and the KRRS group in the embodiments of this application; Figure 9 I is a bar chart of LDA scores for the differentially expressed bacterial groups in the HFD group and the KRRS group in the embodiments of this application; Figure 9 J is a graph showing the relative abundance of different species and the differences between the HFD group and the KRRS group in the embodiments of this application; Figure 9 K is a heatmap of the relative abundance of gut microbiota at the species level in each group of mice in the embodiments of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] In the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0034] The following is in conjunction with the appendix Figures 1 to 9 The present application provides a detailed description of the kudzu root powder, its preparation method, and its application through specific embodiments and application scenarios.

[0035] Example 1

[0036] This embodiment screens the process parameters of the preparation method of kudzu root powder in this application.

[0037] Experimental group 1 The preparation method of kudzu root powder in this embodiment includes the following steps: Step 100: Take 5.05 kg of raw kudzu root powder and record the moisture content of the kudzu root powder; Step 200: Add citric acid to deionized water at 1% of the dry weight of kudzu root powder to prepare an acidified aqueous solution. Spray the acidified aqueous solution evenly onto the kudzu root powder, and mix the acidified aqueous solution with the kudzu root powder to obtain a wet kudzu root powder material with a moisture content of 20%. Step 300: Place the wet kudzu root powder in a sealed environment and allow it to equilibrate at room temperature for 2 hours; Step 400: Spread the material obtained in step 300 evenly in a tray, with a material layer thickness of 1.5cm, and pre-dry it at 50℃ until the moisture content is 10%; Step 500: Bake the pre-dried material at 150℃ for 3 hours, cool it, pulverize it, and pass it through a 100-mesh sieve to obtain baked kudzu root powder.

[0038] The roasted kudzu root powder obtained in this embodiment was tested in vitro using a modified Englyst method. 0.2 g of the sample was reacted in 0.1 mol / L sodium acetate at 37°C, with the addition of α-amylase (580 U / mL) and saccharifying enzyme (30 U / mL). Samples were taken at 20 min and 120 min, the reaction was terminated by boiling water, and after centrifugation, the glucose content of the supernatant was measured. RDS, SDS, and RS were calculated based on G20, G120, and the total starch mass. RDS (%) = 84.3 ± 2.3, SDS (%) = 5.1 ± 2.9, RS (%) = 10.6 ± 0.7. Wherein, RDS (%) = (amount of glucose released within 20 minutes / total starch mass) × 100%. SDS (%) = (Amount of glucose released within 20-120 minutes / Total starch content) × 100% RS (%) = 100% - RDS (%) - SDS (%), that is, RS (%) represents the undigested residue after 120 minutes.

[0039] Table 1 below lists the RDS, SDS, and RS values ​​of roasted kudzu root powder obtained under different experimental conditions for experimental groups 2-22. The preparation methods for experimental groups 2-22 are the same as those for experimental group 1, the difference being the treatment conditions listed in Table 1.

[0040] Table 1. Results of different dry heat treatment conditions and in vitro digestion characteristics.

[0041] The RDS, SDS, and RS of the raw kudzu root powder were 67.7±1.8%, 23.3±4.1%, and 8.9±3.7%, respectively. As shown in Table 1, different pre-spraying solution pH values, different adjusted moisture content, different moisture equilibrium times, different pre-drying temperatures, or different baking temperatures and times all led to varying degrees of change in the RDS, SDS, and RS values ​​of the baked kudzu root powder. Under the conditions of adding 1% citric acid (based on dry starch) to a pre-spraying solution with a pH of 3 (a hydrochloric acid solution with pH=3), adjusting the moisture content of the kudzu root powder to 30%, equilibrating the moisture for 14 hours, drying at 100℃ to 10% moisture content, and then reacting at 130℃ for 5 hours, the RDS, SDS, and RS of the baked kudzu root powder were 41.8±2.9%, 16.8±2.4%, and 41.4±1.6%, respectively, while the resistant starch (RS) significantly increased from 8.9±3.7% to 41.4±1.6%.

[0042] Example 2

[0043] This embodiment tests the roasted kudzu root powder obtained in test group 14 of Example 1.

[0044] (1) The total dietary fiber and puerarin in the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14 were tested.

[0045] The test method for total dietary fiber is GB 5009.88-2023.

[0046] The detection method for puerarin is GB / T 22251-2024.

[0047] Testing revealed that the raw kudzu root powder sample contained 3.69% total dietary fiber and 42.6 mg / 100 g puerarin; the roasted kudzu root powder contained 18.46% total dietary fiber and 69.0 mg / 100 g puerarin. These results indicate that the roasted kudzu root powder obtained in this application has increased levels of both total dietary fiber and puerarin, suggesting that the roasted kudzu root powder possesses the component basis for a kudzu root complex functional powder.

[0048] (2) X-ray diffraction (XRD) was performed on the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14.

[0049] A Bruker D8 Advance diffractometer was used, with 2θ ranging from 4 to 40°, a scanning rate of 10° / min, and a step of 0.04°. The spectra were processed using OriginPro 2024b, and the relative crystallinity was calculated based on the relationship between the area of ​​the crystalline region and the total area.

[0050] The results of XRD analysis of the raw kudzu root powder and the roasted kudzu root powder obtained in experimental group 14 are as follows: Figure 1 As shown. Figure 1In this context, KRS refers to raw kudzu root powder, and KRRS refers to the roasted kudzu root powder of this application. KRS-1, KRS-2, and KRS-3 are three parallel tests of raw kudzu root powder; KRRS-1, KRRS-2, and KRRS-3 are three parallel tests of roasted kudzu root powder, and the test results are taken as the average of the three groups.

[0051] from Figure 1 The results showed that the relative crystallinity of raw kudzu root powder was 28.75±3.35%, while that of roasted kudzu root powder was 37.38±0.52%. Compared with raw kudzu root powder, the relative crystallinity of roasted kudzu root powder was higher.

[0052] (3) Fourier transform infrared spectroscopy (FTIR) was used to detect the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14.

[0053] Shimadzu IRTracer 100 was used, KBr tablet compression method, scanning range 4000~400 cm⁻¹ -1 Transmittance was converted to absorbance, and resolution enhancement was performed using OMNIC 9.0; with a resolution of 1047 / 1022 cm⁻¹. -1 and 995 / 1022 cm -1 The uptake ratio characterizes the short-range order of starch molecules.

[0054] The results of FTIR analysis of the raw kudzu root powder and the roasted kudzu root powder obtained in experimental group 14 are as follows: Figure 2 As shown. Figure 2 In this context, KRS refers to raw kudzu root powder, and KRRS refers to the roasted kudzu root powder of this application. KRS-1, KRS-2, and KRS-3 are three parallel tests of raw kudzu root powder; KRRS-1, KRRS-2, and KRRS-3 are three parallel tests of roasted kudzu root powder, and the test results are taken as the average of the three groups.

[0055] from Figure 2 The results show that the 1047 / 1022 cm⁻¹ content in the raw kudzu root powder is... -1 The ratio was 0.907 ± 0.003, and the content of roasted kudzu root powder was 1047 / 1022 cm⁻¹. -1 The ratio was 0.912 ± 0.006; 995 / 1022 cm⁻¹ in the raw kudzu root powder. -1 The ratio was 0.955 ± 0.002, and the content of roasted kudzu root powder was 995 / 1022 cm⁻¹. -1 The ratio was 0.999±0.004, compared to raw kudzu root powder, the roasted kudzu root powder had 1047 / 1022 cm⁻¹. -1 The ratio and 995 / 1022 cm -1 The ratios all increased.

[0056] (4) Scanning electron microscopy (SEM) was used to detect the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14.

[0057] The surface microstructure of raw kudzu root powder and roasted kudzu root powder was compared using a Carl Zeiss GeminiSEM 360 field emission scanning electron microscope at an accelerating voltage range of 0.02–30 kV. Images at 100x and 1000x magnification were recorded.

[0058] The results of SEM analysis of the raw kudzu root powder and the roasted kudzu root powder obtained in experimental group 14 are as follows: Figure 3 As shown. Figure 3 In this context, KRS refers to raw kudzu root powder, and KRRS refers to the roasted kudzu root powder of this application.

[0059] from Figure 3 The results showed that the surface of roasted kudzu root powder was rougher than that of raw kudzu root powder, possibly due to the presence of starch in the roasted kudzu root powder, resulting in a rougher surface appearance. Figure 3 It can also be seen that the particle size distribution of roasted kudzu root powder is more irregular.

[0060] (5) Differential scanning calorimetry (DSC) was used to detect the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14.

[0061] Grind the sample and pass it through a 100-mesh sieve; weigh 2.5~3.1mg, add deionized water and equilibrate at 4℃ for 24 h; use NETZSCH DSC 300 to heat the sample from 30℃ to 105℃ at a rate of 10℃ / min, and use NETZSCH Assistant 9 to calculate the enthalpy of thermal transition (ΔH), onset temperature (To), peak temperature (Tp) and termination temperature (Tc).

[0062] The results of DSC analysis on the raw kudzu root powder and the roasted kudzu root powder obtained in experimental group 14 are as follows: Figure 4 As shown. Figure 4 In this context, KRS refers to raw kudzu root powder, and KRRS refers to the roasted kudzu root powder of this application. KRS-1, KRS-2, and KRS-3 are three parallel tests of raw kudzu root powder; KRRS-1, KRRS-2, and KRRS-3 are three parallel tests of roasted kudzu root powder, and the test results are taken as the average of the three groups.

[0063] from Figure 4The results showed that the ΔH, To, Tp, and Tc of the raw kudzu root powder were 11.98±0.30 J / g, 64.9±0.2℃, 71.2±0.4℃, and 82.5±0.1℃, respectively; while the ΔH, To, Tp, and Tc of the roasted kudzu root powder were 9.29±0.16 J / g, 59.4±0.5℃, 65.8±0.5℃, and 74.1±1.0℃, respectively. Compared with the raw kudzu root powder, the ΔH, To, Tp, and Tc of the roasted kudzu root powder were all lower.

[0064] (6) Chain length distribution (CLD) was detected in the raw kudzu powder and the roasted kudzu powder obtained in test group 14.

[0065] Purified starch was debranched using a boiling water bath, sodium acetate / isoamylase, and ethanol precipitation, then dissolved in 0.5% LiBr / DMSO. Detection was performed using an Ultimate 3000-OPTILAB T-rEX SEC-RI system with two tandem gel columns at 80°C. This assay was used to compare the relative peak areas of different molecular weight fractions.

[0066] The results of CLD testing on the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14 are as follows: Figure 5 As shown. Figure 5 In this context, KRS refers to raw kudzu root powder, and KRRS refers to the roasted kudzu root powder of this application. KRS-1, KRS-2, and KRS-3 are three parallel tests of raw kudzu root powder; KRRS-1, KRRS-2, and KRRS-3 are three parallel tests of roasted kudzu root powder.

[0067] from Figure 5 The results showed that, compared with kudzu root powder, the number of chain length distribution peaks in roasted kudzu root powder decreased from three to two, and the third peak disappeared. This indicates that the preparation process of roasted kudzu root powder significantly altered the chain length composition of starch molecules, reducing high molecular weight or long-chain components while relatively enriching medium-chain-length components. This change suggests that the treatment process may promote the degradation, rearrangement, and formation of ordered structures in starch chains, thereby facilitating the formation of resistant starch structures.

[0068] The multi-scale detection results of the raw kudzu root powder and the roasted kudzu root powder obtained in test group 14 show that the roasted kudzu root powder of this application exhibits clear, multi-level structural changes in both structure and thermal transformation characteristics compared to the raw kudzu root powder. Specifically, the relative crystallinity of the roasted kudzu root powder increased from 28.75±3.35% in the raw material to 37.38±0.52%; the 1047 / 1022 cm⁻¹, which characterizes short-range order in the Fourier transform infrared spectrum, also showed a significant improvement. -1 The ratio increased from 0.907±0.003 to 0.912±0.006, representing 995 / 1022 cm⁻¹ of the double helix's degree of order. -1The ratio increased from 0.955±0.002 to 0.999±0.004. Differential scanning calorimetry (DSC) showed that the enthalpy of thermal transition (ΔH) decreased from 11.98±0.30 J / g in the raw material to 9.29±0.16 J / g, and the onset temperature (To), peak temperature (Tp), and termination temperature (Tc) shifted from 64.9℃, 71.2℃, and 82.5℃ to 59.4℃, 65.8℃, and 74.1℃, respectively. Scanning electron microscopy (SEM) images also showed a distinct modified rough morphology on the particle surface. Chain length distribution analysis showed that the number of chain length peaks decreased from three in the raw material to two, indicating that the resistant starch preparation process significantly altered the chain length composition of starch molecules, reducing high molecular weight or long-chain components while relatively enriching medium-length components. This change suggests that the treatment process may promote the degradation, rearrangement, and formation of ordered structures in starch chains, thereby facilitating the formation of resistant starch structures. Meanwhile, the in vitro digestibility characteristics changed significantly. The proportion of rapidly digestible starch (RDS) in the sample decreased from 67.7±1.8% in the raw material to 41.8±2.9%, the proportion of slowly digestible starch (SDS) decreased from 23.3±4.1% to 16.8±2.4%, while the proportion of resistant starch (RS) increased significantly from 8.9±3.7% to 41.4±1.6%.

[0069] Example 3

[0070] This embodiment illustrates the application and effect of the roasted kudzu root powder obtained in test group 14 of Example 1 in the preparation of anti-obesity food.

[0071] Animal Ethics: The experiment was approved by the Animal Experiment Ethics Committee of the China-Japan Friendship Hospital, approval number ZRDWLL240067. The experimental animals were 6-week-old male C57BL / 6J mice. After one week of acclimatization, the normal diet group (Chow, n=6) was fed a basal diet; the remaining mice were fed a high-fat diet (D12492) for 11 weeks to model calorie deficiency, and then divided into a high-fat diet (HFD) group, a PLR-S group, and a PLR-RS group (n=6 each) for 8 weeks of intervention. All groups were administered 5 mL / kg / day of deionized water by gavage; the HFD group was administered the high-fat diet (D12492) by gavage, the PLR-RS group was administered 1000 mg / kg body weight / day of the tested resistant starch by gavage, and the PLR-S group was administered approximately 772 mg / kg / day of isocaloric starch by gavage. Body weight and food intake were recorded weekly, and fasting blood glucose was monitored every two weeks.

[0072] Test results as follows Figures 6-9 As shown. Figures 6-9 In this context, Chow refers to the normal feed group, HFD refers to the high-fat feed group, KRS refers to the PLR-S group, and KRRS refers to the PLR-RS group.

[0073] Figure 6This study demonstrates the effects of roasted kudzu root powder on body weight, body composition, adipose tissue, blood glucose, glucose tolerance, insulin resistance, and inflammatory markers in mice with high-fat diet-induced obesity. Figure 6 It was found that, compared with the HFD group, the PLR-RS group, without significant differences in food intake, showed reduced weight gain, decreased fat mass ratio, and increased lean body mass ratio over 8 weeks, as well as a decrease in total adipose tissue and the proportion of iWAT and sWAT adipose tissue. Simultaneously, it reduced fasting blood glucose, fasting insulin, and the insulin resistance index assessed by the homeostasis model, and improved the area under the curve (AUC) of OGTT and ITT. The PLR-RS group also showed reduced serum endotoxin, tumor necrosis factor-α, interleukin-1β, and interleukin-6.

[0074] Figure 7 This study demonstrates the effects of roasted kudzu root powder on blood lipids, liver histology, liver lipid deposition, and liver triglycerides in mice subjected to a high-fat diet-induced obesity. Figure 7 It can be seen that serum triglycerides (TG), free fatty acids (FFA), total cholesterol, and low-density lipoprotein cholesterol were decreased in the PLR-RS group. Liver HE and Oil Red O staining showed reduced lipid deposition and decreased liver TG levels.

[0075] Figure 8 This study demonstrates the effects of roasted kudzu root powder on postprandial lipid response, ileal lipid deposition, fecal triglycerides (TG), and the expression of genes related to intestinal lipid absorption / transport in mice with high-fat diet-induced obesity. Figure 8 It was found that in the oral fat tolerance test, the PLR-RS group showed decreased AUC of postprandial TG and FFA; decreased ileal Oil Red O staining and ileal TG levels; and increased fecal TG levels. The expression of intestinal fat absorption / transport-related genes CD36, FATP4, MOGAT2, MTTP, and APOA4 was downregulated.

[0076] Figure 9 This study demonstrates the effects of roasted kudzu root powder on gut microbiota diversity, community structure, F / B ratio, and differentially expressed flora in high-fat diet-induced obese mice. Figure 9 It can be seen that: gut microbiota analysis shows that PLR-RS can partially alter the composition of gut microbiota related to high-fat diets, and increase the Chao index and decrease the F / B ratio.

[0077] Figures 6-9 The results showed that roasted kudzu root powder exerts its effects by reducing fat accumulation, improving glucose metabolism, reducing inflammation, regulating gut microbiota, and decreasing intestinal fatty acid uptake, triglyceride resynthesis, and the expression of genes related to chylomicron packaging / transport. These results support the use of roasted kudzu root powder in the preparation of functional foods with anti-obesity, improved glucose and lipid metabolism, and inhibitory effects on intestinal lipid absorption.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing kudzu root powder, characterized in that, Includes the following steps: Step 100: Obtain the raw material kudzu root powder; Step 200: Add an acidifying agent to the pre-spraying solution with a pH value of 3-7 to prepare an acidified aqueous solution. Spray the acidified aqueous solution evenly onto the kudzu root powder. After mixing the acidified aqueous solution with the kudzu root powder, the moisture content of the wet kudzu root powder is 20-30%. Step 300: Place the wet kudzu root powder material in a sealed environment to equilibrate; Step 400: After equilibration, pre-dry the material obtained in step 300 until the moisture content is 5-15%; Step 500: After heating the material obtained in step 400, cool it to room temperature and then pulverize it to obtain roasted kudzu root powder.

2. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 100, the raw material kudzu root powder is one or more of the following: whole kudzu root powder, kudzu root starch, a blend of kudzu root powder and whole grain powder, a blend of kudzu root powder and bean powder, and a blend of kudzu root powder and dietary fiber.

3. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 200, the acidifying agent is at least one selected from citric acid, lactic acid, malic acid, tartaric acid, acetic acid, gluconic acid, hydrochloric acid, and phosphoric acid; the amount of acidifying agent added is 1% of the dry weight of the raw kudzu root powder. And / or, in step 200, the pre-spray solution with a pH value of 3 to 7 is deionized water or hydrochloric acid solution; And / or, in step 200, the acidified aqueous solution is uniformly sprayed onto the kudzu root powder by one or more of the following methods: spraying, vacuum mixing, fluidized bed humidification.

4. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 300, the temperature of the sealed environment is 15~30℃; And / or, place the wet kudzu root powder in a sealed environment to equilibrate for 2~14 hours.

5. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 400, the material obtained in step 300 is spread out, wherein the thickness of the spread material layer is 0.5~3.0cm; the pre-drying temperature is 50~100℃; And / or, in step 400, the material obtained in step 300 is pre-dried by introducing one or more of the following methods: hot air, vacuum, infrared, microwave, fluidized bed heating.

6. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 500, the material obtained in step 400 is heated at 130~150℃ for 3~8 hours; And / or, in step 500, the material obtained in step 400 is heated using one or more of the following methods: oven, hot air furnace, drum, fluidized bed, infrared, microwave, continuous belt equipment; And / or, in step 500, when heating the material obtained in step 400, the material obtained in step 400 is heated by a single constant temperature, multi-stage heating or pulse heating method.

7. The method for preparing kudzu root powder according to claim 1, characterized in that, In step 500, the material that has been heated and cooled to room temperature is pulverized and passed through a 60-120 mesh sieve to obtain roasted kudzu root powder. And / or, in step 500, the material that has been heated and cooled to room temperature is pulverized using one or more of the following methods: grinding, air jet milling, ball milling, cryogenic pulverization, extrusion.

8. A kudzu root powder, characterized in that, It is roasted kudzu root powder obtained by the method for preparing kudzu root powder according to any one of claims 1 to 7.

9. The use of the kudzu root powder according to claim 8 in the preparation of anti-obesity foods, foods that assist in weight management, foods that improve glucose and lipid metabolism, foods that reduce intestinal lipid absorption, and / or foods that improve intestinal flora.

10. The application of kudzu root powder according to claim 9, characterized in that, The food product is one or more of the following: instant powder, meal replacement powder, baked goods, cereal products, convenience foods, nutrition bars, or compound powders. in, When the food is a powdered beverage and / or a meal replacement powder, the content of roasted kudzu root powder is 10-80%; When the food is a baked product, the content of baked kudzu root powder is 5-40%; When the food is a cereal product and / or nutrition bar, the content of roasted kudzu root powder is 3-60%; When the food is a convenience food and / or a compound powder, the content of roasted kudzu root powder is 1-15%.

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