Okra polysaccharide as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of plant polysaccharide extraction, and particularly relates to okra polysaccharide as well as a preparation method and application thereof, and the preparation method of the okra polysaccharide comprises the following steps: fermenting okra pericarp by using lactobacillus rhamnosus, and extracting to obtain the okra polysaccharide. The preparation method has excellent extraction efficiency, the viscosity of okra can be reduced, and the extracted okra polysaccharide has high activity; and the okra polysaccharide can significantly promote the proliferation of beneficial bacteria in the intestinal tract and inhibit the proliferation of harmful bacteria.

Description

Technical Field

[0001] The invention belongs to the technical field of plant polysaccharide extraction, and particularly relates to okra polysaccharide and a preparation method and application thereof. Background Art

[0002] Okra [Abelmoschus esculentus (L.) Moench] is an annual dicotyledonous herb of the Malvaceae family, usually grown in tropical and subtropical regions of the world. Okra is rich in polysaccharides and phenolic compounds and flavonol derivatives, mainly oligocatechins. Other components include fat, protein, vitamins, minerals, tannins, etc. In addition, okra has a variety of biological activities, including anti-oxidation, anti-inflammatory, anti-fatigue, anti-tumor, hypoglycemic, hypolipidemic, and improving intestinal function.

[0003] Existing studies have shown that the main health function of okra is related to its high content of okra polysaccharides. However, due to covalent bonding with metal ions, okra polysaccharides have high viscosity and low dissolution rate. At present, the main extraction methods of okra polysaccharides are hot water extraction, ultrasound-assisted extraction, enzyme-assisted extraction, etc., but none of them specifically solve the problem of high viscosity of raw materials, and the existing extraction technology only uses polysaccharide yield as an indicator, and does not take increasing polysaccharide activity as the goal of optimizing and establishing preparation technology.

[0004] Therefore, it is necessary to develop a method for preparing okra polysaccharides that can reduce the viscosity of okra, increase the yield of okra polysaccharides, and simultaneously have high activity. Summary of the invention

[0005] The invention provides a method for preparing okra polysaccharide, which is a method developed based on microbial fermentation, has high extraction efficiency, and can effectively reduce the viscosity of okra; in addition, on this basis, ultrasound and / or microwave-assisted extraction can be used to increase the extraction efficiency and further reduce the viscosity of okra.

[0006] In order to achieve the above object, the present invention can adopt the following technical solutions:

[0007] One aspect of the present invention provides a method for preparing okra polysaccharide, comprising: fermenting okra peel with Lactobacillus rhamnosus to obtain okra polysaccharide by leaching.

[0008] Preferably, in the above preparation method, the okra peel is mixed with a carbon source and then fermented.

[0009] More preferably, the carbon source may be high fructose corn syrup.

[0010] Preferably, the preparation method can meet any one of the following conditions: (i) ultrasonic treatment is performed after fermentation and then extraction; (ii) microwave treatment is performed after fermentation and then extraction; (iii) ultrasonic combined with microwave treatment is performed after fermentation and then extraction; ultrasonic combined with microwave treatment includes: ultrasonic treatment first and then microwave treatment, or microwave treatment first and then ultrasonic treatment.

[0011] More preferably, the preparation method satisfies one or more of the following conditions: (a) ultrasonic treatment includes: treatment at an amplitude of 45%-55% for 25min-35min; (b) microwave treatment includes: treatment at a power of 650W-750W for 1min-10min.

[0012] Preferably, in the above preparation method, the okra peel is pretreated before fermentation, and the pretreatment includes: drying and crushing the okra peel.

[0013] Preferably, in the above preparation method, after extraction, centrifugation is performed to obtain a supernatant, the supernatant is concentrated, ethanol is added, the mixture is allowed to stand, and centrifugation is performed to remove the supernatant; the precipitate is redissolved, concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharide.

[0014] Another aspect of the present invention provides okra polysaccharide, which is prepared by the preparation method of the present invention.

[0015] In another aspect, the present invention provides a composition or preparation, characterized in that it comprises the okra polysaccharide of the present invention.

[0016] In another aspect, the present invention provides a use of the okra polysaccharide of the present invention in the preparation of a preparation for promoting the proliferation of beneficial intestinal bacteria.

[0017] The beneficial effects of the present invention include at least:

[0018] (1) The preparation method of okra polysaccharide provided by the present invention has excellent extraction efficiency and can reduce the viscosity of okra, and the extracted okra polysaccharide has the function of regulating intestinal microecology.

[0019] (2) The okra polysaccharide provided by the present invention can significantly promote the proliferation of beneficial intestinal bacteria and inhibit the proliferation of harmful bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the yield of okra polysaccharide in different pre-treatment methods;

[0021] Figure 2 is the sugar content of okra polysaccharides with different pre-treatment methods;

[0022] Figure 3 is the apparent viscosity of okra polysaccharides after different pretreatment methods;

[0023] Figure 4 The yield of okra polysaccharides assisted by physical field extraction;

[0024] Figure 5 The physical field assisted extraction of sugar content of okra polysaccharides;

[0025] Figure 6 The apparent viscosity of okra polysaccharides extracted by physical field assistance;

[0026] Figure 7 is the rarefaction curve of intestinal flora in each fermentation solution;

[0027] Figure 8 is the Shannon index of the intestinal flora in each fermentation solution;

[0028] Fig. 9 is the Chao1 index of the intestinal flora in each fermentation solution;

[0029] Fig.10 PCoA analysis of intestinal flora in each fermentation solution;

[0030] Fig.11 To investigate the effect of physical field-assisted extraction of okra polysaccharides on intestinal flora at the phylum level;

[0031] Fig.12 The effect of physical field-assisted extraction of okra polysaccharides on intestinal flora at the genus level. DETAILED DESCRIPTION

[0032] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0033] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless the context has a significantly different meaning, expressions in the singular include expressions in the plural. As used herein, it should be understood that terms such as "include", "have", "include" are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials or combinations. The terms of the present invention are disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials or combinations thereof may exist or may be added. As used herein, " / " may be interpreted as "and" or "or", depending on the circumstances.

[0034] The embodiment of the present invention provides a method for preparing okra polysaccharide, comprising: fermenting okra peel with Lactobacillus rhamnosus to extract the okra polysaccharide.

[0035] It should be noted that the preparation of okra polysaccharides by microbial fermentation has lower okra viscosity and higher polysaccharide extraction efficiency than other methods (such as enzyme-assisted preparation, ultrasonic crushing preparation or alcohol soaking preparation).

[0036] In some specific examples, in the above preparation method, okra peel is mixed with a carbon source and then fermented.

[0037] It should be noted that in the present invention, a carbon source can be added during fermentation to provide energy for Lactobacillus rhamnosus and improve the fermentation efficiency.

[0038] In some specific examples, the carbon source may be high fructose corn syrup.

[0039] It should be noted that, as mentioned above, a carbon source can be added to optimize the preparation method. The added carbon source is well known in the art, and preferably high fructose corn syrup, which is more conducive to the preparation method.

[0040] In some specific examples, the preparation method may satisfy any one of the following conditions: (i) ultrasonic treatment followed by extraction after fermentation; (ii) microwave treatment followed by extraction after fermentation; (iii) ultrasonic combined with microwave treatment followed by extraction after fermentation; ultrasonic combined with microwave treatment includes: ultrasonic treatment first, then microwave treatment, or microwave treatment first, then ultrasonic treatment.

[0041] It should be noted that, based on the fermentation extraction, the present invention can further use ultrasound and / or microwave methods to optimize the preparation method, improve the extraction efficiency of the preparation method, and reduce the viscosity of okra.

[0042] In some specific examples, the above preparation method satisfies one or more of the following conditions:

[0043] (a) Ultrasonic treatment includes: treating at an amplitude of 45% to 55% for 25 minutes to 35 minutes; for example, treating at 50% for 30 minutes;

[0044] (b) Microwave treatment includes: treatment at a power of 650W-750W for 1 min-10 min; for example, treatment at 700W for 5 min.

[0045] In some specific examples, in the above preparation method, the okra peel is pretreated before fermentation, and the pretreatment includes: drying and crushing the okra peel.

[0046] It should be noted that before fermentation, in order to improve the fermentation efficiency, the okra peel can be dried and crushed to increase the reaction contact area and improve the fermentation efficiency.

[0047] In some specific examples, in the above preparation method, after extraction, centrifugation is performed to obtain a supernatant, the supernatant is concentrated, ethanol is added, the mixture is allowed to stand, and centrifugation is performed to remove the supernatant; the precipitate is redissolved, concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharide.

[0048] The embodiment of the present invention further provides okra polysaccharide, which is prepared by the preparation method of the present invention.

[0049] It should be noted that the okra polysaccharide prepared by the preparation method of the present invention has excellent activity.

[0050] The embodiment of the present invention further provides a composition or preparation, characterized in that it comprises the okra polysaccharide of the present invention.

[0051] It should be noted that the okra polysaccharide in the present invention can be used in combination with other effective active ingredients to form a composition; in addition, auxiliary materials can be added to prepare different preparations for use, such as tablets, capsules, oral liquids or emulsions.

[0052] The present invention also provides an application of the okra polysaccharide in the present invention in preparing a preparation for promoting the proliferation of beneficial intestinal bacteria.

[0053] It should be noted that the okra polysaccharide in the present invention can significantly increase the Chao1 index and Shannon index of the intestinal flora, indicating that the α-diversity of the intestinal flora can be improved; it shows that okra polysaccharide can selectively regulate the composition of intestinal microorganisms, promote the proliferation of beneficial bacteria, and inhibit the proliferation of harmful bacteria.

[0054] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

[0055] 1. Extraction of Okra Polysaccharides

[0056] Example 1

[0057] (1) Raw material processing: fresh okra was washed, head and tail removed, cut, and dried in an oven at 50°C for 48 h to obtain okra peel. The dried sample was crushed with a high-speed crusher to obtain okra peel dry powder;

[0058] (2) Microbial fermentation: 10 g of okra peel powder was weighed, added to 600 mL of distilled water, added to 2.5% (w / w) fructose syrup, sterilized at 121°C for 20 min, cooled to room temperature, added to 2% (v / v) activated Lactobacillus rhamnosus (108 CFU / mL), fermented anaerobically at 37°C for 20 h, and then inactivated at 100°C for 10 min;

[0059] (3) Extraction: The okra solution was soaked in a 60°C water bath for 4 h, and the residue and supernatant were collected by centrifugation (4500 r / min, 15 min). The above extraction process was repeated twice, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume. Then, 95% ethanol was added to make the final concentration of 80% (ethanol mass fraction), and the mixture was allowed to stand overnight. The supernatant was removed by centrifugation, and the precipitate was collected and re-dissolved with a small amount of water. Finally, the polysaccharide extracted with the assistance of microbial fermentation was obtained after concentration, dialysis, concentration, and freeze-drying.

[0060] Example 2

[0061] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0062] (2) Microbial fermentation: 10 g of okra peel powder was weighed, added to 600 mL of distilled water, added to 2.5% (w / w) fructose syrup, sterilized at 121°C for 20 min, cooled to room temperature, added to 2% (v / v) activated Lactobacillus rhamnosus (108 CFU / mL), fermented anaerobically at 37°C for 20 h, and then inactivated at 100°C for 10 min;

[0063] (3) Ultrasonic-microwave combination: The okra solution after microbial fermentation was ultrasonically treated for 30 minutes at an amplitude of 50%, and then treated for 5 minutes at a microwave power of 700W, and the microwave treatment was repeated 3 times; (4) Extraction: The okra solution was extracted in a 60℃ water bath for 4 hours, and centrifuged (4500r / min, 15min) to collect the residue and supernatant respectively. The above extraction process was repeated 2 times, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume, and then 95% ethanol was added to make the final concentration of 80% (ethanol mass fraction), and it was allowed to stand overnight; the supernatant was removed by centrifugation, the precipitate was collected, and a small amount of water was added to re-dissolve, and finally concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharides extracted by ultrasonic-microwave combination (OP-LUM).

[0064] Example 3

[0065] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0066] (2) Microbial fermentation: 10 g of okra peel powder was weighed, added to 600 mL of distilled water, added to 2.5% (w / w) fructose syrup, sterilized at 121°C for 20 min, cooled to room temperature, added to 2% (v / v) activated Lactobacillus rhamnosus (108 CFU / mL), fermented anaerobically at 37°C for 20 h, and then inactivated at 100°C for 10 min;

[0067] (3) Ultrasound: The okra solution after microbial fermentation was treated with ultrasound at an amplitude of 50% and an ultrasound time of 30 min;

[0068] (4) Extraction: The okra solution was extracted in a 60°C water bath for 4 h, and centrifuged (4500 r / min, 15 min) to collect the residue and supernatant respectively. The above extraction process was repeated twice, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume, and then 95% ethanol was added to make the final concentration 80% (ethanol mass fraction), and then allowed to stand overnight; the supernatant was removed by centrifugation, the precipitate was collected, and a small amount of water was added to re-dissolve, and finally concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharides assisted by ultrasound (OP-LU) extraction.

[0069] Example 4

[0070] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0071] (2) Microbial fermentation: 10 g of okra peel powder was weighed, added to 600 mL of distilled water, added to 2.5% (w / w) fructose syrup, sterilized at 121°C for 20 min, cooled to room temperature, added to 2% (v / v) activated Lactobacillus rhamnosus (108 CFU / mL), fermented anaerobically at 37°C for 20 h, and then inactivated at 100°C for 10 min;

[0072] (3) Microwave: The okra solution after microbial fermentation was treated at a microwave power of 700 W for 5 min, and the treatment was repeated 3 times;

[0073] (4) Extraction: The okra solution was extracted in a 60°C water bath for 4 h, and the residue and supernatant were collected by centrifugation (4500 r / min, 15 min). The above extraction process was repeated twice, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume. Then, 95% ethanol was added to make the final concentration of 80% (ethanol mass fraction), and the mixture was allowed to stand overnight. The supernatant was removed by centrifugation, and the precipitate was collected and re-dissolved with a small amount of water. Finally, the mixture was concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharides extracted with the assistance of microwave (OP-LM).

[0074] Comparative Example 1

[0075] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0076] (2) Enzymatic hydrolysis: Weigh 10 g of okra peel dry powder, add 600 mL of acid solution with a pH of 4.8 (adjusted with saturated citric acid solution), and add 2% cellulase (400 U / mg);

[0077] (3) Extraction: The okra solution was soaked in a 50℃ water bath for 4h, then heated to 100℃ to inactivate the enzyme for 10min until it was inactive, centrifuged (4500r / min, 15min) to collect the supernatant, and the supernatant was concentrated to 1 / 3 of the original volume under reduced pressure, and then 95% ethanol was added to make the final concentration 80% (ethanol volume fraction), and it was allowed to stand overnight. The supernatant was removed by centrifugation, the precipitate was collected, and a small amount of water was added to re-dissolve it. Finally, it was concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharides extracted with enzymatic hydrolysis.

[0078] Comparative Example 2

[0079] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0080] (2) Alcohol soaking: Weigh 10 g of okra peel powder, soak it in 95% ethanol for 24 h, filter it through 100-mesh gauze, dry it in a water bath at 60 °C for 6 h, and add 600 mL of distilled water;

[0081] (3) Extraction: The okra solution was soaked in a 60°C water bath for 4 h, and the residue and supernatant were collected by centrifugation (4500 r / min, 15 min). The above extraction process was repeated twice, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume. Then, 95% ethanol was added to make the final concentration of 80% (ethanol mass fraction), and the mixture was allowed to stand overnight. The supernatant was removed by centrifugation, and the precipitate was collected and re-dissolved with a small amount of water. Finally, it was concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharides extracted with the aid of alcohol immersion.

[0082] Comparative Example 3

[0083] (1) Raw material processing: Wash the fresh okra, remove the head and tail, cut it, and dry it in an oven at 50°C for 48 hours to separate the okra peel. The dried sample is crushed with a high-speed grinder to obtain okra peel dry powder;

[0084] (2) Ultrafine grinding: Use an ultrafine grinder, use a 0.08 mm screen in reverse, set the speed to 10000 rpm, weigh 10 g of okra peel dry powder that has passed through the screen, and add 600 mL of distilled water;

[0085] (3) Extraction: The okra solution was soaked in a 60°C water bath for 4 h, and the residue and supernatant were collected by centrifugation (4500 r / min, 15 min). The above extraction process was repeated twice, and the supernatants were combined and concentrated under reduced pressure to 1 / 3 of the original volume. Then, 95% ethanol was added to make the final concentration of 80% (ethanol mass fraction), and the mixture was allowed to stand overnight. The supernatant was removed by centrifugation, and the precipitate was collected and re-dissolved with a small amount of water. Finally, the okra polysaccharide extracted with the aid of ultrafine grinding was obtained after concentration, dialysis, concentration, and freeze-drying.

[0086] 2. Extraction effect verification

[0087] In the following verification, the specific calculation method of the yield is: calculated based on the ratio of the mass of freeze-dried okra polysaccharides to the mass of okra powder.

[0088] In the following verification, the apparent viscosity test method is: the sample solution is prepared with distilled water, stirred evenly with magnetic force, and then left to stand for more than 12 hours in an environment of 25°C, and then the apparent viscosity of okra polysaccharides extracted by different pretreatment methods is measured using an ARES-G2 rheometer. At the same time, TA-Orchestrator-7 software is used to collect data. Test conditions: 40mm diameter stainless steel cone plate, Gap value of 0.046mm; temperature of 25°C; shear rate of 0.01-1000s-1.

[0089] In the following verification, the experimental method of sugar content: the neutral sugar content was determined by phenol-sulfuric acid method with galactose as the standard. The uronic acid content in polysaccharides was determined by sulfuric acid-carbazole method with galacturonic acid as the standard.

[0090] The yields of okra polysaccharides prepared by the preparation methods of Example 1 and Comparative Examples 1 to 3 were calculated respectively. The results are as follows: Figure 1 As shown in the results, microbial fermentation can significantly increase the yield of okra polysaccharides. The yield of okra polysaccharides obtained by enzymatic hydrolysis is the lowest, and the yields of okra polysaccharides obtained by alcohol soaking and ultrafine grinding are not much different. Figure 2 As shown, the results showed that the uronic acid content of okra polysaccharides extracted by microbial fermentation was significantly higher than that of okra polysaccharides extracted by enzymatic hydrolysis and alcohol soaking.

[0091] The apparent viscosity of okra polysaccharides prepared by the preparation methods of Example 1 and Comparative Examples 1 to 3 is as follows: Figure 3 As shown in the results, the apparent viscosity of okra polysaccharides obtained by the four preparation methods all showed a downward trend with the increase of shear rate, which is a typical non-Newtonian fluid. At the same shear rate, the okra polysaccharide obtained by microbial fermentation has the lowest apparent viscosity. The yields of okra polysaccharides prepared by the preparation methods of Examples 2 to 4 were calculated respectively, and the results are as follows Figure 4 The results show that the ultrasonic-microwave combined assisted extraction can further increase the yield of okra polysaccharides. Figure 5 As shown, the results showed that the neutral sugar content of okra polysaccharides extracted by ultrasound-microwave combined assisted extraction was significantly higher than that of okra polysaccharides extracted by microwave and ultrasound assisted extraction.

[0092] The apparent viscosity of okra polysaccharides prepared by the preparation methods of Examples 2 to 4 is as follows: Figure 6 As shown in the results, the apparent viscosity of okra polysaccharides showed a downward trend with the increase of shear rate, which is a typical non-Newtonian fluid. At the same shear rate, the okra polysaccharides extracted by microwave and ultrasound assisted extraction had a lower apparent viscosity.

[0093] 3. Extracted polysaccharide performance test

[0094] (I) Preparation of fecal bacteria inoculum

[0095] Contact 6 volunteers in advance to collect their fresh feces. The volunteers are all adults in their twenties, including three men and three women. They all have good eating habits and lifestyles, have not suffered from gastrointestinal diseases, and have not taken antibiotics for at least 3 months. After the fecal samples are taken within the time agreed with the volunteers, they are immediately transferred to the anaerobic glove box, weighed and recorded in time. Dilute the fecal sample with PBS buffer solution containing 0.1% L-cysteine ​​salt at a ratio of 1:5 (m:v), stir and mix thoroughly, let it stand for a while, filter the supernatant through a cell sieve, and obtain fecal bacterial liquid. Mix the fecal bacterial liquids of 6 volunteers in equal volumes to obtain the human fecal bacterial liquid required for the experiment.

[0096] (II) Preparation of fermentation medium

[0097] Each liter of basal culture medium contains 2g of tryptone, 2g of yeast extract, 0.1g of NaCl, 0.04g of KH2PO4, 0.04g of K2HPO4, 0.01g of MgSO4·7H2O, 0.0075g of CaCl2, 2g of NaHCO3, 0.5g of L-cysteine ​​hydrochloride, 0.5g of bile salt, 2mL of Tween 80, and 0.5mL of resazurin (0.2%, w / v). 0.5% (w / v) of the fermentation sample is added to the culture medium, and magnetic stirring is used to fully dissolve it. The pH is adjusted to 7.0, and the culture medium is transferred to an autoclave for sterilization (121°C, 15min). After sterilization, the culture medium is transferred to an anaerobic incubator, and hemin and vitamin K1 are added. Take 10 μl of vitamin K1 and dissolve it in 10 ml of anhydrous ethanol, and 5 mg of hemin and dissolve it in 10 ml of 0.1 mol / L NaOH solution. Mix them in equal amounts, filter through a 0.22 μm sterile filter membrane, add them to the culture medium at a ratio of 1% (v / v), and divide the culture medium into sterile centrifuge tubes.

[0098] (III) In vitro simulation of intestinal microbial fermentation process

[0099] In the anaerobic environment of an anaerobic glove box (5% H2, 5% CO2, 90% N2), all sterile centrifuge tubes were inoculated with 2% (v / v) fecal filtrate, shaken repeatedly, and cultured at 37°C in an anaerobic environment. Independent sterile centrifuge tubes were set up, and three parallel experiments were performed for each sample.

[0100] 4. Determination of bacterial flora composition and diversity

[0101] Genomic DNA was extracted using the QIAamp Rapid DNA Stool Mini Kit. The extracted DNA was used as a template to amplify the 16SrRNA gene V3-4 region. Polymerase chain reaction amplification, barcode pyrosequencing of PCR amplicons, and quality control of raw data were performed according to previously described procedures. Raw data to quality OTUs were processed by Qiime2 (version 2020.11). In brief, paired end reads were merged, and amplicon sequence variants (ASVs) were trimmed, filtered, aligned, and clustered using DADA2. Taxonomy was assigned using the Greengenes reference (v13.5) database. Analysis of alpha diversity, beta diversity, and bacterial taxonomic distribution was performed using MicrobiomeAnalyst (version 5.0).

[0102] Rarefaction curves, Chao1 index, and Shannon index were used to analyze the α-diversity of fecal microbiota; among them: Figure 7 This indicates that the sequencing results are sufficient to reflect the diversity contained in the current samples; Figure 8 It was shown that OP-LUM significantly improved the Chao1 index; Fig. 9 As shown in the figure, OP-LM, OP-LU and OP-LUM significantly improved the Shannon index; from the above, it can be seen that OP-LM, OP-LU and OP-LUM can improve the α-diversity of intestinal flora. In addition, PCoA data showed that the microbiota of OP-LM, OP-LU and OP-LUM groups changed ( Fig.10 ); The results of bacterial population analysis at the phylum and genus levels in the blank group and okra polysaccharide group are shown in Fig.11 and Fig.12 shown.

[0103] The above results indicate that OP-LM, OP-LU and OP-LUM can selectively regulate the composition of intestinal microorganisms, promote the proliferation of beneficial bacteria and inhibit the proliferation of harmful bacteria.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing okra polysaccharide, characterized in that: include: The okra peel is fermented with Lactobacillus rhamnosus and okra polysaccharides are extracted.

2. The preparation method according to claim 1, characterized in that: The okra peel is mixed with a carbon source and then fermented.

3. The preparation method according to claim 2, characterized in that: The carbon source was high fructose corn syrup.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The preparation method satisfies any of the following conditions: (i) after fermentation, ultrasonic treatment is performed and then extraction is performed; (ii) after fermentation, microwave treatment is performed followed by extraction; (iii) after fermentation, ultrasonic combined with microwave treatment is performed and then extraction is performed; ultrasonic combined with microwave treatment includes: ultrasonic treatment first and then microwave treatment, or microwave treatment first and then ultrasonic treatment.

5. The preparation method according to claim 4, characterized in that: The preparation method meets one or more of the following conditions: (a) ultrasonic treatment comprising: treating at an amplitude of 45% to 55% for 25 min to 35 min; (b) Microwave treatment includes: treatment at a power of 650 W to 750 W for 1 min to 10 min.

6. The preparation method according to any one of claims 1 to 3 and 5, characterized in that: The okra peel is pretreated before fermentation, and the pretreatment includes: drying and crushing the okra peel.

7. The preparation method according to any one of claims 1 to 3 and 5, characterized in that: After extraction, the supernatant is obtained by centrifugation, the supernatant is concentrated, ethanol is added, the mixture is allowed to stand, and the supernatant is removed by centrifugation; the precipitate is redissolved, concentrated, dialyzed, concentrated, and freeze-dried to obtain okra polysaccharide.

8. Okra polysaccharide, characterized in that The compound is prepared by the preparation method according to any one of claims 1 to 6.

9. A composition or preparation, characterized in that The invention comprises the okra polysaccharide as claimed in claim 8.

10. Use of the okra polysaccharide according to claim 8 in the preparation of a preparation for promoting the proliferation of beneficial intestinal bacteria.

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