Kudzuvine root dietary fiber with blood fat reducing effect and preparation method of kudzuvine root dietary fiber
The method of preparing kudzu dietary fiber by combining pulsed electric field and microwave treatment solves the problem of unsatisfactory blood lipid-lowering effect in the existing technology, and significantly improves its cholesterol adsorption capacity and lipid-lowering effect.
Patent Information
- Application Number
- CN202511436206.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-09
- Publication Date
- 2026-01-02
AI Technical Summary
Existing kudzu dietary fiber has an unsatisfactory effect on lowering blood lipids, and existing preparation methods mainly rely on enzymatic methods, which lack effective lipid-regulating capabilities.
Kudzu dietary fiber was prepared by combining pulsed electric field and microwave treatment. First, it was pulsed for 10 min to 70 min under an electric field of 2 kV/cm to 6 kV/cm, and then treated with microwaves of 200 W to 600 W for 5 min to 45 min to form a complex permeable structure, enhance the specific surface area and adsorption sites, and improve the release efficiency of internal components by combining microwave thermal conduction.
It significantly enhanced the lipid-lowering ability of kudzu dietary fiber, strengthened its cholesterol adsorption capacity, and increased the content and purity of soluble dietary fiber. Both in vitro and in vivo experiments showed excellent lipid-lowering effects.
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Figure CN121242238A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of active ingredient extraction, and particularly relates to a pueraria lobata dietary fiber with a blood lipid-lowering effect and a preparation method thereof. BACKGROUND
[0002] At present, although there are various effective therapeutic drugs such as statins, they can cause adverse side effects on organs, especially the stomach and liver. In addition, exercise and diet-based therapies need to be adhered to for a long time to effectively control such diseases. Therefore, it is urgent to explore some natural therapy functional foods / nutritional supplements with therapeutic potential and beneficial to human health. In this regard, the application of certain natural polysaccharides as dietary intervention means for preventing or treating physiological disorders such as obesity and hyperlipidemia is receiving more and more attention because of their fewer side effects and lower cytotoxicity.
[0003] Dietary fiber is the seventh essential nutrient for maintaining health, and plays an important role in obesity management and hyperlipidemia regulation. Through various mechanisms such as increasing satiety, reducing fat absorption rate, improving intestinal flora, enhancing insulin sensitivity, reducing blood cholesterol and triglyceride levels, dietary fiber can effectively prevent and treat obesity and hyperlipidemia. Therefore, the extraction of natural dietary fiber has become a major research focus. Pueraria lobata is a plant with both medicinal and edible properties, and its roots contain rich dietary fiber. The existing technology for preparing pueraria lobata dietary fiber mainly uses enzyme method. However, the dietary fiber obtained by the above method mainly has good physical properties, especially water absorption and swelling capacity and water retention. Its effect on reducing blood lipids is not ideal. SUMMARY
[0004] In order to solve the above technical problems, the application provides a pueraria lobata dietary fiber with a blood lipid-lowering effect and a preparation method thereof.
[0005] The first aspect of the application provides a preparation method of a pueraria lobata dietary fiber with a blood lipid-lowering effect, comprising the following steps: pulse the pueraria lobata slurry under the condition of an electric field intensity of 2kV / cm-6kV / cm for 10min-70min, and then microwave treat under the condition of a power of 200W-600W for 5min-45min to obtain a pueraria lobata powder suspension; perform enzymolysis on polysaccharides and proteins in the pueraria lobata powder suspension, alcohol precipitation, centrifugal precipitation to obtain the pueraria lobata dietary fiber.
[0006] In the present application, the final puerariae dietary fiber has the optimal lipid-regulating capacity by sequentially performing pulsed electric field treatment at 2 kV / cm-6 kV / cm for 10 min-70 min and then microwave treatment at 200 W-600 W for 5 min-45 min. The pulsed electric field treatment is performed first to make the puerariae dietary fiber form a more complex structure with strong permeability, increase the specific surface area and adsorption sites. The subsequent microwave treatment can change the chemical properties while maintaining the structure, thereby improving the adsorption capacity. The two treatment methods complement each other, and the structural changes caused by the pulsed treatment make the microwave treatment more easily penetrate into the fiber interior, thereby improving the release efficiency of internal components, enhancing the release of functional factors such as small molecular weight polysaccharides, and enhancing the lipid-regulating capacity.
[0007] In another preferred embodiment, the flow rate of the pulsed electric field treatment is 100 mL / min-250 mL / min, and the frequency is 1 kHz-1.1 kHz.
[0008] In another preferred embodiment, the temperature of the microwave treatment is 50℃-90℃.
[0009] In another preferred embodiment, the preparation process of the puerariae slurry is as follows: After the puerariae is crushed, puerariae powder is obtained, and the puerariae powder is mixed with water to obtain a puerariae slurry.
[0010] In another preferred embodiment, the solid-liquid ratio of the puerariae powder to water is 1 g: 40 mL-45 mL.
[0011] In another preferred embodiment, the specific process of the enzymatic hydrolysis is as follows: After the puerariae powder is crushed, puerariae powder is obtained, and the puerariae powder is mixed with water to obtain a puerariae slurry.
[0012] In another preferred embodiment, the volume ratio of the alpha-amylase to the puerariae powder suspension is 1:800-820; The volume ratio of the alkaline protease to the puerariae powder suspension is 1:400-420; The volume ratio of the saccharifying enzyme to the puerariae powder suspension is 1:400-420; The concentration of the amylase is 40000 U / g-50000 U / g; the concentration of the alkaline protease is 200000 U / g-300000 U / g; and the concentration of the saccharifying enzyme is 100000 U / g-200000 U / g.
[0013] In another preferred embodiment, the specific process of alcohol precipitation is as follows: after enzymolysis, 4-5 times the volume of ethanol is added, and the mixture is allowed to stand for 8-12 hours.
[0014] The second aspect of the present application provides the Pueraria lobata dietary fiber prepared by the preparation method of the Pueraria lobata dietary fiber.
[0015] In another preferred embodiment, the Pueraria lobata dietary fiber is used for reducing high blood lipids.
[0016] Compared with the prior art, the present application has the following beneficial effects: In the present application, the final Pueraria lobata dietary fiber has the optimal lipid-regulating capacity by sequentially performing pulsed electric field treatment at 2 kV / cm-6 kV / cm for 10-70 min and then microwave treatment at 200 W-600 W for 5-45 min. The sequence can ensure the integrity of the fiber structure, and the physical field energy is more uniform and penetrates more deeply by using electroporation to enhance cell permeability and microwave heat conduction, thereby improving the release efficiency of internal components, enhancing the release of functional factors such as small-molecular-weight polysaccharides in dietary fiber, and enhancing the lipid-regulating capacity. The Pueraria lobata dietary fiber prepared by the physical field coupling has the soluble dietary fiber content increased to 15.51%±2.88%, the insoluble dietary fiber / soluble dietary fiber ratio of 3.72, the product purity increased to 73.19%±0.86%, the water-holding capacity, oil-holding capacity and swelling capacity increased to 8.95 g / g±0.24 g / g, 13.41 g / g±0.22 g / g and 7.25 g / mL±0.14 g / mL, respectively, and the Pueraria lobata dietary fiber prepared by the method has good in-vivo and in-vitro lipid-regulating capacity. By comparing the in-vitro lipid-regulating capacity of the samples obtained under different treatment sequences and the high-fat mouse model experiment, it is verified that the combination of pulsed electric field treatment first and then microwave treatment has better effect on reducing blood lipids than other treatment combinations. In the in-vitro experiment, the cholesterol adsorption capacity and the bile acid adsorption capacity are significantly better than those of microwave treatment alone or microwave-pulsed sequence. In the in-vivo experiment, the total cholesterol, triglyceride and low-density lipoprotein cholesterol in the blood of mice are significantly better than those of microwave treatment alone or microwave-pulsed sequence. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 A result graph of the cholesterol adsorption capacity of the Pueraria lobata dietary fiber obtained by treatment under different pulsed electric field intensities.
[0018] Figure 2The result chart of the adsorption capacity of the pueraria dietary fiber obtained by different microwave treatment powers on cholesterol.
[0019] Figure 3 The result chart of the adsorption capacity of the pueraria dietary fiber obtained by different treatment methods on cholesterol and cholic acid.
[0020] Figure 4 The result chart of the influence of the pueraria dietary fiber obtained by different treatment methods on the total cholesterol content in the blood of mice.
[0021] Figure 5 The result chart of the influence of the pueraria dietary fiber obtained by different treatment methods on the triglyceride content in the blood of mice.
[0022] Figure 6 The result chart of the influence of the pueraria dietary fiber obtained by different treatment methods on the low-density lipoprotein cholesterol content in the blood of mice. DETAILED DESCRIPTION
[0023] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.
[0024] The experimental methods described in the following embodiments are all conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.
[0025] The following describes a pueraria dietary fiber with a blood lipid-lowering effect, a preparation method thereof and an application thereof.
[0026] The heat-stable alpha-amylase, alkaline protease and glucoamylase used in the following embodiments are purchased from Shanghai Yuanye Biotechnology Co., Ltd.
[0027] Embodiment 1, a preparation method of a pueraria dietary fiber with a blood lipid-lowering effect, comprises the following steps.
[0028] S1, mix the pueraria powder with water according to a solid-liquid ratio of 1:40 to obtain a pueraria slurry.
[0029] S2, pass the pueraria slurry into a pulsed electric field with an electric field intensity of 2 kV / cm and a frequency of 1.01 kHz at a flow rate of 100 mL / min for 10 min to obtain a pueraria slurry after pulsed electric field treatment; microwave treat the pueraria slurry after pulsing under the condition of a power of 200 W and a temperature of 50℃ for 5 min to obtain a pueraria powder suspension.
[0030] S3, adjust the pH value of the pueraria powder suspension to 8.1, add 1.25 mL of heat-stable alpha-amylase, react at 95°C for 60 min, cool to 60°C, then add 2.5 mL of alkaline protease, react at 60°C for 60 min, adjust the pH value to 4.5, then add 2.5 mL of saccharifying enzyme, react at 60°C for 30 min, and then complete the enzymolysis to obtain the enzymolyzed pueraria powder suspension. The volume ratio of the heat-stable alpha-amylase to the pueraria powder suspension is 1:800, the volume ratio of the alkaline protease to the pueraria powder suspension is 1:400, and the volume ratio of the alkaline protease to the pueraria powder suspension is 1:400. The concentration of the heat-stable alpha-amylase is 40,000 U / g, the concentration of the alkaline protease is 200,000 U / g, and the concentration of the saccharifying enzyme is 100,000 U / g.
[0031] S4, mix the enzymolyzed pueraria powder suspension with 95 wt% ethanol at a temperature of 60°C at a volume ratio of 1:4, stand for 8 h of precipitation, then centrifuge at 4,000 rpm for 15 min, take the precipitate, and vacuum freeze-dry to obtain the pueraria dietary fiber.
[0032] Example 2, a preparation method of pueraria dietary fiber with a blood lipid-lowering effect, comprising the following steps.
[0033] S1, mix the pueraria whole powder with water at a solid-liquid ratio of 1:40 to obtain pueraria slurry.
[0034] S2, pass the pueraria slurry into a pulsed electric field at a flow rate of 180 mL / min, and process for 30 min under the conditions of an electric field intensity of 3.3 kV / cm and a frequency of 1.01 kHz to obtain pulsed electric field treated pueraria slurry; microwave treat the pulsed pueraria slurry under the conditions of a power of 400 W and a temperature of 60°C for 15 min to obtain pueraria powder suspension.
[0035] S3, adjust the pH value of the pueraria powder suspension to 8.1, then add heat-stable alpha-amylase, react at 95°C for 60 min, cool to 60°C, then add alkaline protease, react at 60°C for 60 min, adjust the pH value to 4.5, then add saccharifying enzyme, react at 60°C for 30 min, and then complete the enzymolysis to obtain the enzymolyzed pueraria powder suspension. The volume ratio of the heat-stable alpha-amylase to the pueraria powder suspension is 1:800, the volume ratio of the alkaline protease to the pueraria powder suspension is 1:400, and the volume ratio of the alkaline protease to the pueraria powder suspension is 1:400. The concentration of the heat-stable alpha-amylase is 40,000 U / g, the concentration of the alkaline protease is 200,000 U / g, and the concentration of the saccharifying enzyme is 100,000 U / g.
[0036] S4, the enzyme hydrolysis of the puerariae radix powder suspension and 95wt% ethanol at a temperature of 60℃ according to the volume ratio of 1:5, after 10h of standing precipitation, centrifugation at 4000rpm for 15 minutes, vacuum freeze-drying of the precipitate, puerariae radix dietary fiber can be obtained.
[0037] Example 3, a preparation method of puerariae radix dietary fiber with hypolipidemic effect, comprising the following steps.
[0038] S1, the puerariae radix powder and water were mixed according to the solid-liquid ratio of 1:40 to obtain puerariae radix slurry.
[0039] S2, the puerariae radix slurry was passed into the pulsed electric field at a flow rate of 250mL / min, the electric field intensity was 6kV / cm, and the frequency was 1.01kHz, and the treatment time was 70min to obtain the puerariae radix slurry after pulsed electric field treatment; the puerariae radix slurry after pulsed electric field treatment was microwave treated under the conditions of power of 600W and temperature of 90℃ for 45min to obtain the puerariae radix powder suspension.
[0040] S3, the pH value of the puerariae radix powder suspension was adjusted to 8.3, heat-stable alpha-amylase was added, and the reaction was carried out at 100℃ for 90min, then cooled to 65℃, added alkaline protease, and reacted for 90min, then adjusted the pH value to 4.5, added saccharifying enzyme, and reacted at 65℃ for 60min to complete the enzyme hydrolysis, and obtain the enzyme hydrolysis of the puerariae radix powder suspension. The volume ratio of heat-stable alpha-amylase to puerariae radix powder suspension was 1:800, the volume ratio of alkaline protease to puerariae radix powder suspension was 1:400, and the volume ratio of alkaline protease to puerariae radix powder suspension was 1:400; the concentration of heat-stable alpha-amylase was 40000U / g, the concentration of alkaline protease was 200000U / g, and the concentration of saccharifying enzyme was 100000U / g.
[0041] S4, the enzyme hydrolysis of the puerariae radix powder suspension and 95wt% ethanol at a temperature of 60℃ according to the volume ratio of 1:4, after 8h of standing precipitation, centrifugation at 4000rpm for 15 minutes, vacuum freeze-drying of the precipitate, puerariae radix dietary fiber can be obtained.
[0042] Comparative example 1, a preparation method of puerariae radix dietary fiber with hypolipidemic effect, except that the microwave treatment was carried out first and then the pulsed treatment, which was different from example 1, and the remaining steps were the same as example 1.
[0043] The adsorption capacity of cholesterol of the puerariae radix dietary fiber prepared in example 1~example 3 was determined, and the results were shown in table 1.
[0044] Table 1 the adsorption capacity of cholesterol of the puerariae radix dietary fiber prepared in example 1~example 3 The soluble dietary fiber, the insoluble dietary fiber / soluble dietary fiber ratio and the product purity in the Comparative Example 1, the Example 1 to the Example 3 were determined, and the results are shown in Table 2.
[0045] Table 2 Determination results From the results in Table 2, it can be seen that the method in the Example 1 to the Example 3 obtains the puerariae dietary fiber with higher soluble dietary fiber content, which indicates that the exchange of the pulse and the microwave in sequence has great influence on the soluble dietary fiber content.
[0046] In order to further determine the influence of the pulse electric field intensity and the microwave treatment power on the puerariae dietary fiber, the following experiments were conducted.
[0047] The method in the Example 1 was adopted to conduct the pulse treatment under the conditions that the electric field intensity was 2 kV / cm, 3.3 kV / cm, 4.6 kV / cm and 6 kV / cm respectively, and the pulse treatment was not conducted as a control, and the obtained puerariae dietary fiber was used for the adsorption of cholesterol, and the specific results are shown in Table 3. Figure 1
[0048] The cholesterol adsorption experiment was specifically as follows: 20 mL of fresh egg yolk and 90 mL of distilled water were mixed and stirred into an egg yolk emulsion. 0.5 g of puerariae dietary fiber was added into 15 mL of the egg yolk emulsion, and after 2 h of incubation at 37℃, centrifugation was conducted at 4500 rpm for 15 min. 1 mL of supernatant was accurately removed, and ice acetic acid was used for constant volume to 10 mL to obtain a dilution liquid. Then, 0.4 mL of the dilution liquid, 0.2 mL of 1 mg / mL o-phthaldehyde solution and 4 mL of mixed acid solution were taken, and after being fully mixed, reaction was conducted for 10 min, and the absorbance value was determined at 550 nm wavelength. The mixed acid solution was prepared by ice acetic acid and sulfuric acid in a volume ratio of 1:10.
[0049] A blank control group was set in the experiment, and 15 mL of the egg yolk emulsion without the addition of puerariae dietary fiber was used as a reference. According to the cholesterol standard curve y=0.2755x-0.0887, R 2 =0.9987, quantitative determination was conducted, and the results are shown in Table 3. The cholesterol adsorption capacity was calculated according to the formula: Figure 1
[0050] ; In the calculation formula, c1 represents the initial cholesterol content of the egg yolk emulsion, the unit is mg; c2 is the residual cholesterol amount after adsorption, the unit is mg; and m refers to the sample weight, the unit is g.
[0051] From the results in Table 3, it can be seen that the puerariae dietary fiber obtained by the pulse treatment under the electric field intensity of 2 kV / cm has the highest cholesterol adsorption capacity, and the puerariae dietary fiber obtained by the pulse treatment under the electric field intensity of 6 kV / cm has the lowest cholesterol adsorption capacity. Figure 1 It can be seen that the adsorption effect of kudzu dietary fiber treated with a pulsed electric field on cholesterol is significantly higher than that of untreated fiber. Furthermore, the adsorption effect is optimal at an electric field strength of 4.6 kV / cm. Further increases in electric field strength reduce the adsorption capacity, mainly because excessively strong pulsed electric field treatment may cause excessive damage or denaturation to the structure of kudzu dietary fiber. Some active functional groups in dietary fiber, such as hydroxyl (-OH) and carboxyl (-COOH), are key sites for cholesterol binding. Excessive electric field strength may damage the structure of these functional groups, reducing their binding sites with cholesterol molecules and thus decreasing their adsorption capacity. In addition, high-intensity pulsed electric field treatment may cause rearrangement or aggregation of dietary fiber molecules, forming larger molecular aggregates. This can mask or reduce the originally dispersed adsorption sites. Therefore, the optimal electric field strength is 4.6 kV / cm.
[0052] Using the method described in Example 1, microwave treatment was performed at power levels of 200W, 300W, 400W, 500W, and 600W, with no microwave treatment serving as a control. The obtained kudzu dietary fiber was used to adsorb cholesterol. Specific results are as follows: Figure 2 As shown. From Figure 2 It can be seen that the cholesterol adsorption effect of kudzu dietary fiber after microwave treatment is significantly higher than that of untreated kudzu, and the cholesterol adsorption effect increases with increasing power.
[0053] from Figure 1 and Figure 2 The results show that the electric field strength has a greater impact on the adsorption of cholesterol by kudzu dietary fiber than the microwave treatment power. This is mainly because pulsed electric field treatment enables kudzu dietary fiber to form a more complex and permeable structure, increasing its specific surface area and enriching its network structure, thus providing more adsorption sites. Microwave treatment mainly exposes the accessible edges of the dietary fiber and increases its crystallinity. Although it can also improve functional properties, its structural changes may not be as significant as those caused by pulsed electric field treatment. Therefore, combining pulsed electric field treatment with microwave treatment can effectively improve the adsorption effect of kudzu dietary fiber on cholesterol.
[0054] To further illustrate the effect of the order of microwave and pulse treatment on the adsorption of cholesterol and bile acids by kudzu dietary fiber, the following experiment was conducted.
[0055] Pulsed electric field intensity of 4.6 kV / cm, microwave treatment power of 600 W, the rest of the steps are the same as example 1 to prepare the puerariae dietary fiber is recorded as the first pulse after the microwave group, the microwave treatment and pulse treatment order is exchanged, the puerariae dietary fiber prepared is recorded as the first microwave after the pulse group, the puerariae dietary fiber obtained by only microwave treatment is recorded as the microwave treatment group, the puerariae dietary fiber obtained by only pulse treatment is recorded as the pulse treatment group, the puerariae dietary fiber obtained without pulse treatment and microwave treatment is recorded as the untreated group, by comparing the in vitro lipid-lowering ability of the samples obtained under different treatment orders and the high-fat mouse model experiment, it is verified that the first pulse after the microwave group is better than other treatment combinations in lowering blood lipids. In vitro experiments, cholesterol adsorption capacity and bile acid adsorption capacity are significantly better than microwave or microwave-pulse sequence alone, as shown in Figure 3 In vivo experiments, the total cholesterol, triglyceride and low density lipoprotein cholesterol of mice blood are significantly better than microwave or microwave-pulse sequence alone, as shown in Figures 4-6
[0056] The in vivo experiment is as follows: 84 mice, 7 weeks old, weighing 22.49±0.57 g, are divided into groups of 12. They are raised in an environment with a 12-hour day-night cycle, a temperature of 22℃±2℃ and a relative humidity of 60%±5%. All mice are fed with normal control group diet and water in the laboratory environment for one week. The experimental animals are randomly divided into seven groups: the normal control group is recorded as NC, the high-fat model group is recorded as MC, the puerariae dietary fiber group is recorded as PLDF, the gavage amount is 250 mg / kg, the pulse electric field pretreated puerariae dietary fiber group is recorded as PEF-PLDF, the gavage amount is 250 mg / kg, the microwave pretreated puerariae dietary fiber group is recorded as M-PLDF, the gavage amount is 250 mg / kg, the pulse electric field coupled microwave pretreated puerariae dietary fiber group is recorded as PEFM-PLDF, the gavage amount is 250 mg / kg. NC group is fed with normal diet, and the rest of the groups are fed with high-fat diet; among them, the high-fat diet is composed of the following raw materials in mass percentage: 10% lard, 20% sucrose, 2.5% cholesterol, 1% sodium cholate and the rest 66.5% normal diet, which builds a hyperlipidemia model while also performing gavage intervention. During the ten-week experiment, body weight and food intake are tracked every week. On the day before the tenth week, the mice are fasted and deprived of water for 12 hours. Glass capillary tubes are used to collect blood samples from the orbital venous plexus of the mice, and the contents of total cholesterol, triglyceride and low density lipoprotein cholesterol are determined and compared with the control group. All mice are fasted and deprived of water for 12 hours at the end of the tenth week when gavage is performed for the last time. The blood is taken from the eye orbit by enucleation, and after the blood collection is completed, the mice are sacrificed by cervical dislocation. The in vitro experiment is as follows.
[0057] Cholesterol adsorption capacity: 20 mL of fresh egg yolk and 90 mL of distilled water were mixed to form an egg yolk emulsion. 0.5 g of pueraria dietary fiber was added to 15 mL of the emulsion, which was incubated at 37 °C for 2 h and then centrifuged at 4500 rpm for 15 min. 1 mL of supernatant was accurately removed and diluted to 10 mL with glacial acetic acid. Then, 0.4 mL of the diluted solution was added to 0.2 mL of 1 mg / mL o-phthaldehyde solution and 4 mL of mixed acid solution; after mixing well, the reaction was allowed to proceed for 10 min, and the absorbance was measured at 550 nm. The mixed acid solution was prepared by mixing glacial acetic acid and sulfuric acid at a volume ratio of 1:10.
[0058] A blank control group was set up, and 15 mL of egg yolk emulsion without the addition of pueraria dietary fiber was used as a reference. According to the cholesterol standard curve y = 0.2755x - 0.0887, R2= 0.9987, the cholesterol adsorption capacity was expressed as the number of milligrams of cholesterol bound by 0.5 g of pueraria dietary fiber.
[0059] Bile acid adsorption capacity: 10 mg of sample was dispersed in 1 mL of 1 M CaCl2solution, then mixed with 100 µL of 0.01 M HCl, and stirred at 37 °C for 1 h to obtain a mixture. Then the mixture was neutralized with 0.1 M NaOH, and then incubated with 500 µL of 400 µM bile acid solution at 37 °C for 1 h to obtain a reaction mixture. The bile acid solution was prepared in 0.01 M phosphate buffer with a pH of 7.0. Then, the reaction mixture was centrifuged at 9100 g for 10 min. The supernatant was collected for determination of cholic acid. The concentration of unbound bile acid was determined by a kit. The bile acid adsorption capacity was expressed as the number of milligrams of bile acid bound by 1.0 g of sample.
[0060] From Figures 3-6The results in the above examples can be concluded that the cholesterol adsorption capacity and the cholic acid adsorption capacity in the in vitro experiment are significantly better than those of the microwave or the microwave-pulse sequence alone. The total cholesterol, the triglyceride and the low density lipoprotein cholesterol in the blood of the mice in the in vivo experiment are significantly better than those of the microwave or the microwave-pulse sequence alone. This is mainly due to the fact that in the pulse electric field-microwave sequence treatment, the cell wall structure of the pueraria dietary fiber is first electroporated and micro-injured by the pulse electric field treatment, forming a highly permeable and porous network structure, which significantly improves the specific surface area and the number of effective adsorption sites. Subsequent microwave treatment does not significantly damage the existing structure, but through its thermal effect and molecular polarization, it further regulates the chemical composition and the exposure of polar groups on the fiber surface, enhancing its affinity for cholesterol and cholic acid. This synergistic mechanism of structure first and then function enables the dietary fiber to have stronger physical adsorption and chemical combination dual capabilities. In contrast, in the "microwave-pulse electric field" sequence treatment, the initial microwave action may lead to the densification of the structure of the dietary fiber and the increase of the crystallinity, thereby inhibiting the deep restructuring ability of the subsequent pulse electric field on the structure. Although the pulse electric field may still cause a certain degree of structural loosening, it is difficult to reverse the highly ordered and compact structure caused by the microwave. In addition, the microwave treatment may cause certain heat-induced changes to the functional groups on the fiber surface, such as covering or inactivating some of the polar groups such as hydroxyl or carboxyl groups, thereby affecting the interaction with the cholesterol molecules. The subsequent pulse electric field treatment is also difficult to effectively restore these chemically active sites, and may even exacerbate the structural damage, thereby weakening the adsorption and lipid-lowering effect of the fiber.
[0061] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, which are all included in the protection scope of the present application.
Claims
1. A method for preparing Pueraria dietary fiber having a blood lipid-lowering effect, characterized by, The method comprises the following steps: pulse the puerariae slurry under the condition of electric field intensity of 2 kV / cm-6 kV / cm for 10 min-70 min, and then microwave treat the puerariae slurry under the condition of power of 200 W-600 W for 5 min-45 min to obtain a puerariae powder suspension; perform enzymolysis on polysaccharides and proteins in the puerariae powder suspension, alcoholize after the enzymolysis, centrifugalize, take the precipitate to obtain the puerariae dietary fiber.
2. The method of preparing dietary fiber of Radix Puerariae according to claim 1, characterized by, The flow rate of the pulse electric field treatment is 100 mL / min-250 mL / min, and the frequency is 1 kHz-1.1 kHz.
3. The method for preparing kudzu dietary fiber according to claim 1, characterized in that, The temperature of the microwave treatment is 50 DEG C-90 DEG C.
4. The method for preparing kudzu dietary fiber according to claim 1, characterized in that, The preparation process of the puerariae slurry is as follows: crush the puerariae to obtain a puerariae powder, mix the puerariae powder with water to obtain the puerariae slurry.
5. The method for preparing kudzu dietary fiber according to claim 4, characterized in that, The ratio of the puerariae powder to water is 1 g:40 mL-45 mL.
6. The method of claim 1, wherein the dietary fiber is prepared from the roots of Pueraria montana var. lobata. The specific process of the enzymolysis is as follows: add heat-stable alpha-amylase in the puerariae powder suspension, react at 95 DEG C-100 DEG C for 60 min-90 min, cool to 60 DEG C, add alkaline protease, react at 60 DEG C-65 DEG C for 60 min-90 min, adjust the pH of the suspension to 4.5, add saccharifying enzyme, and react at 60 DEG C-65 DEG C for 30 min-60 min.
7. The method for preparing kudzu dietary fiber according to claim 6, characterized in that, The volume ratio of the alpha-amylase to the puerariae powder suspension is 1:800-820; The volume ratio of the alkaline protease to the puerariae powder suspension is 1:400-420; The volume ratio of the saccharifying enzyme to the puerariae powder suspension is 1:400-420; The concentration of the alpha-amylase is 40 000 U / g-50 000 U / g, the concentration of the alkaline protease is 200 000 U / g-300 000 U / g, and the concentration of the saccharifying enzyme is 100 000 U / g-200 000 U / g.
8. The method for preparing kudzu dietary fiber according to claim 1, characterized in that, The specific process of the alcoholization is as follows: after the enzymolysis, add 4-5 times volume of ethanol, and stand for 8 h-12 h. 9.A puerariae dietary fiber prepared by the method of any one of claims 1-8.
10. The dietary fibre of Pueraria montana var. phaseolica according to claim 9, wherein, The puerariae dietary fiber is used for reducing high blood fat.