Chuzhou chrysanthemum water-soluble polysaccharide as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of Chuzhou chrysanthemum water-soluble polysaccharide and application of the Chuzhou chrysanthemum water-soluble polysaccharide as a rice juice stabilizer, and belongs to the technical field of Chuzhou chrysanthemum polysaccharide extraction.The preparation method comprises the steps that firstly, Chuzhou chrysanthemum is soaked and pretreated with ethyl alcohol, then the ethyl alcohol is removed, and pretreated chrysanthemum filter residues are obtained; 2, the obtained pretreated chrysanthemum filter residues are subjected to water extraction, a sodium bicarbonate water solution serves as a water extraction system, and first-step treatment is conducted for 5-10 min under the dual-action conditions of 10-15 KHz ultrasonic treatment and 200-300 Mpa pressure; then carrying out intermittent 10-15 KHz ultrasonic treatment, and carrying out second-step treatment for at least 1 hour under the conditions that the air pressure is 50-60 kpa and the temperature is 80-86 DEG C, so as to obtain a water extraction filtrate; 3, mixing the obtained water extraction filtrate with ethanol, and precipitating, wherein the ethanol concentration in the mixed system is 35-50%; and 4, collecting the precipitate, dissolving the precipitate, dialyzing with running water, and freeze-drying to obtain the water-soluble polysaccharide of Chuzhou chrysanthemum. According to the method, the polysaccharide obtaining rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of chrysanthemum polysaccharide, and more specifically, to a water-soluble chrysanthemum polysaccharide and a preparation method and application thereof. Background Art

[0002] Chuju has multiple edible and medicinal values, and polysaccharides are important biologically active ingredients in Chuju.

[0003] At present, water extraction and alkali extraction are the most commonly used methods for polysaccharide extraction, such as announcement number CN104292350 A, a Chinese patent published on January 21, 2015, discloses an extraction process and application of chrysanthemum polysaccharide, which adopts a process of water extraction followed by alkali extraction, and the specific steps include: 1) mixing: removing impurities and washing the chrysanthemum, adding distilled water, and crushing it with a grinder at high speed to obtain a mixed solution; wherein, the water content of the chrysanthemum is 5% by weight, and the weight of the added distilled water is 20-40 times the weight of the chrysanthemum; 2) water extraction: under the condition of a heating temperature of 80-100°C, the mixed solution in step 1) is magnetically stirred for 2-3 hours, and then the mixed solution is filtered with a filter cloth to obtain a filtrate, which is a water extract, and the filter residue is taken out for alkali extraction; 3) alkali extraction: adding NaOH solution to the filter residue in step 2), magnetically stirring under heating conditions, and filtering with a filter cloth after a period of time to obtain a filtrate, which is an alkali extract; wherein the concentration of the NaOH solution is 0.5-1 mol / L, and the weight added is 20 times the weight of the filter residue. -40 times, the heating temperature is 80-100°C, and the stirring time is 2-3 hours; 4) dialysis: add 6 mol / L hydrochloric acid to the alkaline extract of step 3), adjust the pH value of the solution to 7, and then dialyze with a dialysis bag; the dialysis bag used for the dialysis has a molecular weight cutoff of 3500Da, and the dialysis time is 24 hours; 5) concentration: combine the water extract in step 2) and the alkaline extract after dialyzation in step 4), and concentrate to 1 / 20 of the original volume under the condition of heating temperature of 80°C to obtain a concentrated solution; 6) precipitation: add ethanol to the concentrated solution of step 5), let it stand overnight to remove protein; the amount of ethanol added is such that the final volume percentage concentration of ethanol in the mixed solution is greater than 80%; 7) rinsing: centrifuge the concentrated solution obtained after standing overnight in step 6), remove the supernatant, and rinse the precipitate with a low boiling point organic solvent; 8) drying: blow dry the precipitate after rinsing in step 7) to obtain chrysanthemum antioxidant polysaccharide. The final polysaccharide yield of this process is only 5.21% (w / w) at most, which is still relatively low. Therefore, it is urgent to design an extraction and preparation method with a high extraction rate. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for preparing water-soluble polysaccharides from Chrysanthemum morifolium with antioxidant activity, so as to improve the yield of polysaccharides.

[0005] Another object of the present invention is to provide a use of the Chuju water-soluble polysaccharide prepared by the above method as a rice dew stabilizer.

[0006] In order to achieve the purposes of the present invention, the present invention provides a method for preparing a water-soluble polysaccharide of Chrysanthemum morifolium, comprising: Step 1: In order to remove pigments and lipids, the chrysanthemum is first pretreated by soaking in 95% ethanol, and then the ethanol is removed to obtain a pretreated chrysanthemum residue; Step 2: In order to promote the dissolution of polysaccharides, the obtained pre-treated chrysanthemum residue is subjected to water extraction; a sodium bicarbonate aqueous solution is used as the water extraction system, and the first step of treatment is carried out for 5 to 10 minutes under the dual conditions of 10 to 15 KHz ultrasonic treatment and 200 to 300 MPa pressure; then, the second step of treatment is carried out for at least 1 hour under the conditions of intermittent 10 to 15 KHz ultrasonic treatment, 50 kpa to 60 kpa air pressure, and 80 to 86° C. temperature to obtain a water extraction filtrate; Step 3: The obtained water extract filtrate is mixed with ethanol for precipitation, and the ethanol concentration in the mixed system is 35% to 50%; Step 4: collecting the precipitate, dissolving the precipitate, dialyzing it with running water, and freeze-drying it to obtain the water-soluble polysaccharide of Chuju.

[0007] Preferably, in step 2, the first step of treatment uses 15 KHz ultrasonic treatment and 250 MPa high pressure treatment for 10 minutes.

[0008] Preferably, in step 2, the second step treatment uses 15 KHz ultrasonic treatment for 10 minutes, with an interval of 10 minutes, and this cycle is repeated for periodic ultrasonic treatment.

[0009] Preferably, the concentration of the sodium bicarbonate aqueous solution is 1 mol / L.

[0010] Preferably, in step three, the ethanol concentration of the mixed system is first adjusted to 35% for first-stage precipitation, the precipitate is collected, and then the ethanol concentration of the mixed system is adjusted to 50% for second-stage precipitation, the precipitate is collected, and the precipitates are combined.

[0011] Most preferably, in step 2, the filter residue is first mixed with a sodium bicarbonate aqueous solution; in the first step, 15 KHz ultrasonic treatment and 250 MPa high pressure treatment are used for 10 minutes; in the second step, 15 KHz ultrasonic treatment is used for 10 minutes under 50 kpa-60 kpa pressure and 80-86° C. temperature conditions, followed by a 10-minute pause, and the cycle is repeated for periodic ultrasonic treatment, and extraction is performed for 2 hours to obtain a filtrate; In step three, the ethanol concentration of the mixed system is first adjusted to 35% for the first stage precipitation, the precipitate is collected, and then the ethanol concentration of the mixed system is adjusted to 50% for the second stage precipitation, the precipitate is collected, and after the precipitates are combined, the precipitates are dissolved in water, the dissolved precipitates are dialyzed together with running water, and freeze-dried to obtain Chuju water-soluble polysaccharides with good antioxidant effect.

[0012] Preferably, in the method for preparing the water-soluble polysaccharide from Chrysanthemum morifolium, water extraction is performed using an extraction device.

[0013] The present invention provides a water-soluble polysaccharide of chrysanthemum obtained by any one of the above preparation methods.

[0014] The present invention provides an application of the Chuju water-soluble polysaccharide prepared by any one of the above preparation methods as a rice dew stabilizer.

[0015] The present invention has at least the following beneficial effects: 1. The present invention uses sodium bicarbonate aqueous solution as a water extraction system and adopts a two-step method for water extraction. The first step adopts an ultrasonic + high-pressure treatment process. The ultrasonic cavitation effect is more significant under high-pressure conditions, which increases the permeability of chrysanthemum cell membranes, promotes the interaction between water molecules and chrysanthemum cells, and improves the polysaccharide extraction effect and efficiency; the second step adopts a gap ultrasound + low pressure + low-temperature boiling treatment process to accelerate the dissolution of polysaccharides, improve the polysaccharide extraction rate, reduce high-temperature inactivation, and maintain the activity of polysaccharides. The obtained Chuju water-soluble polysaccharide has good antioxidant properties. Since uronic acid is relatively stable under alkaline conditions, the extracted polysaccharide has a high uronic acid content.

[0016] 2. The present invention uses 35% ethanol and 50% ethanol to precipitate the chrysanthemum water extract filtrate step by step, thereby reducing the damage of high-concentration ethanol to the chrysanthemum polysaccharide precipitation, further improving the yield of chrysanthemum water-soluble polysaccharides, and solving the technical problems that the prior art uses high-concentration ethanol precipitation to cause hydrolysis of chrysanthemum polysaccharides, and some polysaccharide molecules are combined with alcohol-soluble proteins, so that the polysaccharides are also dissolved in the ethanol solution and are not precipitated; at the same time, the dissolution amount of some alcohol-soluble impurities and highly lipophilic components increases, which finally leads to a decrease in the polysaccharide yield.

[0017] 3. When the Chuju water-soluble polysaccharide prepared by the present invention is used as a rice dew stabilizer, the stability of the rice dew can be effectively improved, the centrifugal sedimentation rate is small, and the stability is good.

[0018] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the extraction device described in the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to examples so that those skilled in the art can implement the invention with reference to the description.

[0021] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0022] like Figure 1 As shown, the extraction device used in the present invention can realize pressurization, negative pressure and ultrasonic treatment operations, and comprises: The container body 10 has an inner liner, which has a accommodating cavity 101. The accommodating cavity 101 is used to accommodate the chrysanthemum, the extract material of the present invention. The container body is provided with a cover body 103, which closes the top of the container body to make the accommodating cavity 101 airtight. The cover body 101 is provided with a barometer 104, which is connected to the accommodating cavity 101 and is used to detect the pressure of the accommodating cavity in real time. The bottom of the container body 10 is provided with a discharge port 102, which is connected to the accommodating cavity 101.

[0023] The temperature control unit 20 is used to control the temperature of the receiving chamber; Figure 1 As shown, the temperature control unit includes a heating module (such as a heating wire) arranged around the circumference of the inner tank, a temperature detection module for detecting the temperature of the accommodating cavity, and a temperature control module. The temperature control module is connected to the heating module and the temperature detection module. When the temperature of the accommodating cavity is lower than a set threshold, the heating module is started for heating. When it is higher than the set threshold, the heating module is turned off, thereby controlling the temperature of the accommodating cavity within a set range.

[0024] The ultrasonic unit 30 is arranged at the bottom of the container body. The ultrasonic unit 30 includes a plurality of ultrasonic transducers. The vibrators of the ultrasonic transducers extend into the interior of the containing cavity to generate ultrasonic waves to act on the materials and water in the containing cavity.

[0025] The pressure control unit 40 includes a pump body, which is connected to the accommodating chamber 101 through a pipeline. The pump body pumps the accommodating chamber into a negative pressure through suction, and increases the pressure of the accommodating chamber by pumping gas.

[0026] The condenser 50 is connected to the pump output end of the pressure control unit 40 and is mainly used to condense the gas extracted from the pump. The condensed gas is discharged or collected into other containers.

[0027] Example 1 Precipitation using 35% ethanol The dried Chuju was crushed and passed through a 40-mesh sieve to obtain dried chrysanthemum powder. 100 g of dried chrysanthemum powder was weighed and soaked in 95% ethanol at room temperature of 20-25°C and stirred for 12 h. The mixture was filtered with a filter cloth and repeated once to obtain a filter residue.

[0028] The ethanol in the obtained filter residue is evaporated, and then the filter residue and 3L of 1 mol / L sodium bicarbonate aqueous solution are added to the containing chamber of the extraction device to start a two-step extraction: the first step is to use 15 KHz ultrasonic treatment and 250 MPa high pressure treatment for 10 minutes; the second step is to use 15 KHz ultrasonic treatment for 10 minutes under 50kpa~60kpa low pressure and 80~86°C temperature conditions (in this example, the real-time air pressure is 58 kPa and the boiling water temperature is 85°C), pause for 10 minutes, and repeat this cycle for periodic ultrasonic treatment, extract for 2 hours, filter, and collect the filtrate.

[0029] The filtrate was concentrated to about 300 mL using a rotary evaporator, and the ethanol concentration of the solution was adjusted to 35% for precipitation (stored in a refrigerator at 4°C for 12 h). The precipitate was collected, dissolved in hot water, dialyzed in running water (3500 Da) for 72 h, and then freeze-dried to obtain Chuju water-soluble polysaccharides (CJPs), named CJP-35.

[0030] Example 2: Using 35%+50% ethanol for precipitation The dried Chuju was crushed and passed through a 40-mesh sieve to obtain dried chrysanthemum powder. 100 g of dried chrysanthemum powder was weighed and soaked in 95% ethanol at room temperature of 20-25°C and stirred continuously for 12 h. The mixture was filtered with a filter cloth and repeated once.

[0031] The ethanol in the obtained filter residue is evaporated, and then the filter residue and 3L of 1 mol / L sodium bicarbonate aqueous solution are added to the containing chamber of the extraction device to start a two-step extraction: the first step is to use 15 KHz ultrasonic treatment and 250 MPa high pressure treatment for 10 minutes; the second step is to use 15 KHz ultrasonic treatment for 10 minutes under 50kpa~60kpa low pressure and 80~86°C temperature conditions (in this example, the real-time air pressure is 58 kPa and the boiling water temperature is 85°C), pause for 10 minutes, and repeat this cycle for periodic ultrasonic treatment, extract for 2 hours, filter, and collect the filtrate.

[0032] The filtrate was concentrated to about 300 mL using a rotary evaporator, the ethanol concentration of the solution was adjusted to 35% for precipitation (stored in a 4°C refrigerator for 6 h), the precipitate was collected, and then the ethanol concentration of the solution was adjusted to 50% for precipitation (stored in a 4°C refrigerator for 6 h), the precipitate was collected, the precipitate was combined, the precipitate was dissolved in hot water, dialyzed in running water (3500 Da) for 72 h, and then freeze-dried to obtain Chuju water-soluble polysaccharides (CJPs), named CJP-35+CJP-50.

[0033] Comparative Example 1 The difference from Example 1 is that water is used as the water extraction system, and extraction is carried out at normal pressure in a beaker, and the other steps are the same.

[0034] Specifically include: Step 1: Crush the dried Chuju and pass it through a 40-mesh sieve to obtain dried chrysanthemum powder. Weigh 100 g of dried chrysanthemum powder and soak it in 95% ethanol at room temperature of 20-25°C and stir it continuously for 12 h. Filter it with a filter cloth and repeat once to obtain a filter residue.

[0035] Step 2: evaporate the ethanol in the obtained residue, then add the residue and 3L of water into a beaker, heat and extract on a heatable magnetic stirrer, keep boiling water state under standard atmospheric pressure (measured real-time atmospheric pressure 101 kPa, boiling water temperature 100°C), extract for 3 hours, filter, and collect the filtrate.

[0036] Step 3: Use a rotary evaporator to concentrate the filtrate to about 300 mL, adjust the ethanol concentration of the solution directly to 35% for precipitation (stored in a refrigerator at 4 °C for 12 h), collect the precipitate, dissolve the precipitate in hot water, dialyze with running water (3500 Da) for 72 h, and then freeze-dry to obtain Chuju water-soluble polysaccharides (CJPs), named D1-CJP-35.

[0037] Comparative Example 2 The difference from Comparative Example 1 is that in step 3, the ethanol concentration is directly adjusted to 50% for precipitation, and the other steps are the same to obtain Chuju water-soluble polysaccharides (CJPs), named D2-CJP-50.

[0038] Comparative Example 3 The difference from Comparative Example 1 is that in step 3, the ethanol concentration is directly adjusted to 65% for precipitation, and the other steps are the same to obtain Chuju water-soluble polysaccharides (CJPs), named D3-CJP-65.

[0039] Comparative Example 4 The difference from Comparative Example 1 is that in step 3, the ethanol concentration is directly adjusted to 80% for precipitation, and the other steps are the same to obtain Chuju water-soluble polysaccharides (CJPs), named D4-CJP-80.

[0040] Effect experiment 1. Determination of total sugar content in polysaccharides The phenol-sulfuric acid method was used to determine the total sugar content in the polysaccharide.

[0041] Preparation of reference solution: The concentration of anhydrous glucose is 0.10 mg / mL. Preparation of standard curve: Take 0.0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 mL of reference solution, place them in 10 mL colorimetric tubes, add water to 1 mL, add 1 mL of 5% phenol solution, shake well, add 5 mL of sulfuric acid, shake well, heat in a boiling water bath for 20 minutes, take out and cool in an ice water bath for 5 minutes, shake well, use 0.0 mL colorimetric tube as blank, measure absorbance at a wavelength of 490 nm, fit the standard curve, y=8.136x+0.018, R 2 =0.9995. Preparation of sample solution: Take samples from the water-soluble polysaccharides of Chrysanthemum chrysanthemum obtained in Examples 1-2 and Comparative Examples 1-4 to prepare polysaccharide aqueous solutions with a concentration of 0.6-0.8 mg / mL. Take 0.1 mL of the polysaccharide sample solution, place it in a 10 mL colorimetric tube, add water to make it 1 mL, and measure the absorbance according to the method prepared by the standard curve and calculate the total sugar content according to the standard curve. The results are shown in Table 1: Table 1 Comparison of the yield of water-soluble polysaccharides from Chrysanthemum morifolium in the examples and comparative examples As can be seen from Table 1 above, from the comparison of Comparative Examples 1 to 4, it can be seen that the yield of the sample decreases with the increase of the alcohol precipitation concentration. Since the polysaccharide molecules are combined with alcohol-soluble proteins, the polysaccharides are also dissolved in the ethanol solution and are not precipitated; at the same time, the dissolution amount of some alcohol-soluble impurities and lipophilic components increases, which together lead to a reduction in the polysaccharide yield. From the comparison of Example 1 and Comparative Example 1, it can be seen that compared with the use of water system atmospheric pressure water extraction, the present invention uses a sodium bicarbonate aqueous solution system, combined with a two-step extraction, which can effectively improve the polysaccharide extraction rate. The reason may be in the following aspects: first, the sodium bicarbonate aqueous solution is a weak alkaline medium, which can reduce the hydrolysis reaction of polysaccharides under strong alkaline conditions; second, ultrasonic cavitation combined with high pressure conditions can increase the permeability of chrysanthemum cell membranes, promote the effect of extraction solvents and chrysanthemum cells, and improve the polysaccharide extraction effect and efficiency; third, intermittent ultrasound combined with low-pressure treatment can accelerate polysaccharide dissolution, improve polysaccharide extraction rate, and low-pressure boiling can reduce the damage of high temperature to polysaccharide substances.

[0042] Compared with Example 1, Example 2 first uses 35% ethanol concentration for precipitation, then uses 50% ethanol for precipitation, and combines the precipitations, which again significantly improves the polysaccharide yield.

[0043] 2. Determination of uronic acid content in polysaccharides The content of uronic acid was determined by the sulfuric acid-carbazole method.

[0044] Preparation of reference solution: Take 2mg of glucuronic acid and dilute to 50mL, with a concentration of 0.04mg / mL. Preparation of 0.125% carbazole reagent: Accurately weigh 0.125g of carbazole and dissolve it in 100mL of anhydrous ethanol. Preparation of sulfuric acid-borax solution: Dissolve 2.375g of sodium tetraborate in 25mL of hot water, dissolve it in 225mL of concentrated sulfuric acid under precooling conditions, and mix well. Preparation of standard curve: Accurately pipette 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0mL of standard GlcUA (glucuronic acid) solution, add water to 1mL, precool and keep in an ice water bath, then add 5mL of sulfuric acid-borax solution and cool to room temperature. Heat the test tube in a boiling water bath for 10min, then cool to room temperature, add 0.2mL of carbazole reagent, shake well, continue to heat in a boiling water bath for 15min, and cool to room temperature. The absorbance was measured at 530 nm and the standard curve was fitted, y = 13.504x-0.0396, R 2 =0.9969. Take 0.1 mL of the polysaccharide sample solution, place it in a 10 mL colorimetric tube, add water to make up to 1 mL, and measure the absorbance according to the method prepared by the standard curve and calculate the uronic acid content based on the standard curve.

[0045] Table 2 Comparison of uronic acid content in water-soluble polysaccharides of Chrysanthemum morifolium in Examples and Comparative Examples Uronic acid is a special component in polysaccharide molecules and has multiple biological activities, such as antioxidant, anti-inflammatory, immunomodulatory and antiviral activities.

[0046] Example 1 uses a sodium bicarbonate aqueous solution system, combined with a two-step extraction method, and uses 35% ethanol concentration precipitation to obtain Chuju polysaccharide. Since low-concentration ethanol has limited hydrolysis of glycosidic bonds in Chuju polysaccharide, and uronic acid is relatively stable under alkaline conditions, the uronic acid content in Chuju polysaccharide is significantly higher than that in Comparative Example 1, which uses 35% ethanol concentration precipitation to obtain Chuju polysaccharide. However, since high-concentration ethanol has a certain hydrolysis effect on glycosidic bonds in Chuju polysaccharide, causing part of the uronic acid to be released and unable to be precipitated, the uronic acid content in the polysaccharide components precipitated by different concentrations of ethanol in Comparative Examples 1 to 4 shows a trend of decreasing with increasing ethanol concentration. Example 2 adds 50% ethanol concentration precipitation, so the uronic acid content in the obtained Chuju polysaccharide is also very high.

[0047] 3. In vitro antioxidant test (1) Determination of DPPH free radical scavenging ability Prepare the sample solutions of Chuju polysaccharide with concentrations of 0.05, 0.10, 0.25, 0.50, and 1.00 mg / mL in sequence. Pipette 150 μL of the freshly prepared 0.1 mmol / L DPPH-50% ethanol solution and 50 μL of different sample solutions with different concentrations and mix them in a 96-well plate. React at room temperature in the dark for 40 min. Measure the absorbance at a wavelength of 517 nm. Each sample is measured in parallel 3 times. The sample solution of the positive control group is replaced by Vc, and the sample solution of the blank control group is replaced by ultrapure water solution. The DPPH free radical scavenging rate is calculated according to formula (1): DPPH free radical scavenging rate / %=[1-(A 2- A1) / A0]×100 (1) Among them, A2 is the absorbance of the sample and DPPH; A1 is the absorbance of the sample and DPPH solvent (50% ethanol); A0 is the absorbance of the sample solvent (distilled water) and DPPH.

[0048] Table 3 Comparison of DPPH radical scavenging rates of water-soluble polysaccharides from Chrysanthemum morifolium in Examples and Comparative Examples The comparison of DPPH radical scavenging rates of water-soluble polysaccharides of Chuju in various embodiments and comparative examples is shown in Table 3. It can be seen that the DPPH radical scavenging ability of the polysaccharides prepared in Examples 1 and 2 of the present invention is lower than but closer to vitamin C (Vc), and the DPPH radical scavenging ability of the polysaccharides extracted in Comparative Example 3 is poor, which is only 53.26% at a concentration of 1.0 mg / mL, while the highest of other comparative examples is only 65.93%.

[0049] Example 3 Application of Chuju Water-soluble Polysaccharide as Rice Dew Stabilizer The Chuju water-soluble polysaccharide obtained in Examples 1-2 was added to the rice dew, and the addition ratio was 0.02% (mass ratio).

[0050] Effect experiment This embodiment is experimented with a mass ratio of 0.02%. In actual production, the requirements of GB2760-2014 "National Food Safety Standard for the Use of Food Additives" must be met.

[0051] The water-soluble polysaccharides of Chuju in Examples 1-2 and Comparative Examples 1-4 were added to rice dew at a mass ratio of 0.02% to obtain rice dew samples. 10 mL of the rice dew samples were accurately measured and added to centrifuge tubes, and the mass was recorded as m1. The samples were centrifuged at 5000 r / min for 10 min, and the supernatant was discarded and inverted for 5 min. The mass was measured as m2, and the mass of the centrifuge tube was m0. The centrifugal sedimentation rate = (m2-m0) / (m1-m0)×100%, and each sample was repeated 3 times.

[0052] The results are shown in Table 4: Table 4 Comparison of the effects of water-soluble polysaccharides of Chuju as rice dew stabilizers in the examples and comparative examples It can be seen that compared with comparative examples 1 to 4, the polysaccharides prepared in Examples 1 to 2 of the present invention can effectively and significantly improve the stability of the rice dew products, and have a low centrifugal sedimentation rate and good stability.

[0053] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized.

Claims

1. A method for preparing water-soluble polysaccharide from Chrysanthemum chinense, characterized in that: include: Step 1: pre-treating the chrysanthemum by soaking it in ethanol, and then removing the ethanol to obtain a pre-treated chrysanthemum residue; Step 2: The obtained pre-treated chrysanthemum residue is subjected to water extraction, using a sodium bicarbonate aqueous solution as the water extraction system, and the first step of treatment is performed for 5 to 10 minutes under the dual action conditions of 10 to 15 KHz ultrasonic treatment and 200 to 300 MPa pressure; then, the second step of treatment is performed for at least 1 hour under the conditions of intermittent 10 to 15 KHz ultrasonic treatment, 50 kpa to 60 kpa air pressure, and 80 to 86° C. temperature to obtain a water extraction filtrate; Step 3: The obtained water extract filtrate is mixed with ethanol for precipitation, and the ethanol concentration in the mixed system is 35% to 50%; Step 4: collecting the precipitate, dissolving the precipitate, dialyzing it with running water, and freeze-drying it to obtain the water-soluble polysaccharide of Chuju.

2. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 1, characterized in that: In step 2, the first step uses 15 KHz ultrasonic treatment and 250 MPa high pressure treatment for 10 minutes.

3. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 2, characterized in that: In step 2, the second step uses 15 KHz ultrasonic treatment for 10 minutes, with an interval of 10 minutes, and this cycle is repeated for periodic ultrasonic treatment.

4. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 3, characterized in that: The concentration of the sodium bicarbonate aqueous solution is 1 mol / L.

5. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 1 or 3, characterized in that: In the step three, the ethanol concentration of the mixed system is first adjusted to 35% for the first stage precipitation, the precipitate is collected, and then the ethanol concentration of the mixed system is adjusted to 50% for the second stage precipitation, the precipitate is collected again, and then the precipitates are combined.

6. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 1, characterized in that: Specifically include: Step 1: After the dried Chuzhou chrysanthemum powder is pretreated by soaking in 95% ethanol for 12 hours, the ethanol is removed to obtain a pretreated chrysanthemum residue; Step 2: The obtained pre-treated chrysanthemum residue is added to a 1 mol / L sodium bicarbonate aqueous solution system, and the first step is to use 15 KHz ultrasonic treatment and 250 MPa high pressure treatment for 10 minutes; the second step is to use 15 KHz ultrasonic treatment for 10 minutes, with an interval of 10 minutes, and so on. Periodic ultrasonic treatment is performed, and extraction is performed for 2 hours under 50 kpa~60 kpa pressure and 80~86°C temperature conditions to obtain a water extract filtrate; Step 3: The obtained water filtrate is mixed with ethanol to form a mixed system for precipitation. The ethanol concentration of the mixed system is first adjusted to 35% for the first stage precipitation, and the precipitate is collected. Then, the ethanol concentration of the mixed system is adjusted to 50% for the second stage precipitation, and the precipitate is collected; Step 4: Combine the two precipitates obtained and dissolve them in water, dialyze the dissolved precipitate with running water, and freeze-dry to obtain the Chuju water-soluble polysaccharide.

7. The method for preparing the water-soluble polysaccharide of Chrysanthemum morifolium according to claim 6, characterized in that: Water extraction was performed using an extraction apparatus.

8. A water-soluble polysaccharide of Chrysanthemum morifolium obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the water-soluble polysaccharide of Chuju prepared by the preparation method according to any one of claims 1 to 7 as a rice dew stabilizer.

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