Preparation method and application of bitter bamboo shoot polysaccharide

Abstract

The invention discloses a preparation method and application of bitter bamboo shoot polysaccharide. The preparation method of the bitter bamboo shoot polysaccharide comprises the following steps: uniformly stirring bitter bamboo shoot pulp and water, adding beta-glucosidase, extracting, centrifuging, adding ethanol into the obtained supernatant for alcohol precipitation, and taking the precipitate, namely the bitter bamboo shoot polysaccharide. The yield of the bitter bamboo shoot polysaccharide prepared by the method is more than 7.0%, and the bitter bamboo shoot polysaccharide has good alpha-glucosidase inhibitory activity and antioxidant activity and can be used for preparing food with the effects of reducing blood sugar or resisting oxidation.

Description

Technical Field

[0001] The invention belongs to the technical field of bitter bamboo shoot processing, and particularly relates to a preparation method and application of bitter bamboo shoot polysaccharide. Background Art

[0002] Bitter bamboo shoots, also known as sweet bamboo shoots and cool bamboo shoots, are the tender shoots of the Gramineae plant bitter bamboo. They are a nutritious traditional food and also a Chinese medicinal material. China is one of the earliest countries to eat bamboo shoots, with a history of more than 3,000 years, which was first recorded in the Tang Dynasty's "Compendium of Materia Medica". Bitter bamboo shoots are mainly widely grown in southern China, such as Guangdong, Jiangsu, Zhejiang, Sichuan and other places. They usually grow in some mountainous areas far away from pollution. They do not need fertilizers and pesticides, and generally there is no pesticide residue. The bamboo shoots are protected by bamboo shoot shells, and pollutants are difficult to contact with the edible parts. They have the characteristics of fresh fragrance, slightly bitter, white and crispy meat, and contain a variety of nutrients, such as crude fiber, vitamins, mineral elements, etc., with high nutritional value. It is a traditional green edible forest vegetable. Bitter bamboo shoot polysaccharide is one of the main active ingredients of bitter bamboo shoots, which has nutritional effects such as antioxidant, antiviral, anti-tumor, blood pressure reduction, blood sugar reduction, and blood lipid reduction.

[0003] Chinese patent application CN116425901A discloses bitter bamboo shoot polysaccharide and its preparation method and use, using bitter bamboo shoot powder as raw material, adding water, leaching at 55-90°C for 60-180min, the material-liquid ratio of bitter bamboo shoot to water is: 1:10-50g / mL, filtering, concentrating the filtrate, adding 95% ethanol to precipitate overnight, centrifuging to obtain polysaccharide precipitation, freeze-drying, and obtaining bitter bamboo shoot crude polysaccharide; adding chloroform-n-butanol to deproteinize, adding 30% H2O2 to depigment, separating, and purifying. The bitter bamboo shoot polysaccharide of the invention has high purity and clear polysaccharide structure. Using macrophage RAW264.7 as a cell model, the purified bitter bamboo shoot polysaccharide is evaluated for immune activity, and has good immunomodulatory activity, which provides a theoretical basis for the development and application of bitter bamboo shoot polysaccharide in the fields of food and medicine, and is conducive to the high-value utilization of bitter bamboo shoot resources.

[0004] Chen Guangjing et al. disclosed a bamboo shoot polysaccharide and its preparation method and application (CN117624391A). The preparation method is as follows: (1) drying and crushing fresh bamboo shoots, soaking them in petroleum ether to remove fat, and drying to obtain bamboo shoot powder; (2) taking the bamboo shoot powder and mixing it evenly with deionized water, standing in a water bath for extraction, cooling to room temperature, and centrifuging to obtain an extract; (3) concentrating the extract to obtain a concentrated solution, adding ethanol to the concentrated solution and standing for alcohol precipitation, centrifuging to obtain a polysaccharide precipitate, and washing the precipitate with anhydrous ethanol, ether and acetone in turn, dissolving the precipitate with deionized water, and freeze-drying to obtain a polysaccharide dry sample; (4) eluting and dialyzing the polysaccharide dry sample to obtain a dialysate, and freeze-drying to obtain a crude bamboo shoot polysaccharide.

[0005] The above schemes do not mention the α-glucosidase inhibitory activity of bitter bamboo shoot polysaccharides. However, the method used in the present invention is simple to operate, has mild reaction conditions, is low-cost, is pollution-free, and the yield of bitter bamboo shoot polysaccharides obtained is as high as 7.0% or more, and has good in vitro antioxidant activity and α-glucosidase inhibitory activity. Summary of the invention

[0006] The invention provides a preparation method and application of bitter bamboo shoot polysaccharide. The invention extracts bitter bamboo shoot polysaccharide by enzymatic hydrolysis, which is simple to operate, mild in reaction conditions, low in cost and pollution-free. The yield of bitter bamboo shoot polysaccharide obtained is as high as more than 7.0%, and has good in vitro antioxidant activity and α-glucosidase inhibitory activity.

[0007] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0008] The present invention provides a method for preparing bitter bamboo shoot polysaccharide, comprising the following steps:

[0009] The bitter bamboo shoot pulp is mixed evenly with water, β-glucosidase is added for extraction, and the mixture is centrifuged. Ethanol is added to obtain the supernatant for precipitation, and the precipitate is bitter bamboo shoot polysaccharide.

[0010] Further preferably, the mass ratio of the bitter bamboo shoot slurry to water is 1:5 to 1:20.

[0011] More preferably, the extraction temperature is 35-55° C.; the extraction time is 2-4 hours.

[0012] Further preferably, the bitter bamboo shoot slurry is obtained by cutting bitter bamboo shoots into pieces and then crushing them;

[0013] More preferably, the extraction is followed by cooling in an ice bath to room temperature.

[0014] More preferably, the added amount of the β-glucosidase is 1%-3% of the weight of the bitter bamboo shoot pulp.

[0015] Further preferably, the centrifugal speed is 6000-8000 r / min; the centrifugal time is 20-30 min.

[0016] More preferably, the volume concentration of ethanol after adding ethanol is 70-80% (v / v).

[0017] More preferably, the yield of the bitter bamboo shoot polysaccharide is above 7.0%.

[0018] The invention provides bitter bamboo shoot polysaccharide, which is prepared by the above-mentioned preparation method.

[0019] Further preferably, the monosaccharide composition of the bitter bamboo shoot polysaccharide is composed of arabinose, galactose, glucose, xylose and galacturonic acid, and the molar ratio of each monosaccharide component is 10-14:15-19:60-78:12-16:1.00.

[0020] Preferably, the monosaccharide composition of the bitter bamboo shoot polysaccharide is composed of arabinose, galactose, glucose, xylose and galacturonic acid, and the molar ratio of each monosaccharide component is 13.79:15.37:64.15:13.16:1.00.

[0021] Further preferably, the bitter bamboo shoot polysaccharide has good antioxidant activity and α-glucosidase inhibitory activity.

[0022] The present invention provides the use of the bitter bamboo shoot polysaccharide in preparing foods with blood sugar lowering or anti-oxidation effects.

[0023] Further preferably, the food is a functional food, and the food includes one of tablets and oral liquid products.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) After adding β-glucosidase during the extraction of bitter bamboo shoot polysaccharides of the present invention, the α-glucosidase inhibitory activity of the obtained bitter bamboo shoot polysaccharides is significantly improved.

[0026] (2) The bitter bamboo shoot polysaccharide obtained by the present invention has a yield of more than 7.0% and has good α-glucosidase inhibitory activity and antioxidant activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a line graph of the inhibition rate of bitter bamboo shoot polysaccharide prepared in Example 4 on α-glucosidase. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with examples, but the implementation manner and protection scope of the present invention are not limited to the following examples.

[0029] Related detection and evaluation methods related to the effects of the present invention:

[0030] 1. Determination of the yield of bitter bamboo shoot polysaccharides

[0031] Refer to Liu Qiuye et al. (Liu Qiuye, Liu Hui, Chen Xin, et al. Optimization of extraction process and biological activity analysis of Buzha leaf polysaccharides [J]. Food Industry Science and Technology, 2024, 45(04): 197-204.) The phenol-sulfuric acid method was used to determine the total sugar content in bitter shoots; refer to Zhao Yafei et al. The 3,5-dinitrosalicylic acid (DNS) method was used to determine the reducing sugar content in bitter shoots (Zhao Yafei, Li Chunmei, Min Yiting, et al. Optimization of extraction process of red date polysaccharides and preparation of granules [J]. Guangzhou Chemical Industry, 2022, 50(10): 36-40.).

[0032] Bitter bamboo shoot polysaccharide content = total sugar content - reducing sugar content.

[0033] The yield of bitter bamboo shoot polysaccharides was calculated according to the following formula.

[0034]

[0035] Wherein, c is the determined bitter bamboo shoot polysaccharide content, mg / L; n is the dilution factor; V is the volume of bitter bamboo shoot polysaccharide extract, mL; and m is the amount of bitter bamboo shoot sample (based on dry weight).

[0036] 2. Determination of α-glucosidase inhibition rate

[0037] 50 μL of each sample solution of different concentrations was added to 100 μL of phosphate buffer (PBS, pH 5.8) containing α-glucosidase (3U / mL) solution, incubated at 37°C for 10 min, 50 μL of p-nitrophenyl-aD-pyranoglucoside (5 mmol / L) was added, incubated at 37°C for 60 min, 50 μL of Na2CO3 (1 mol / L) was added to terminate the reaction, and the absorbance A1 at 405 nm was measured. All operations were performed in a 96-well plate, and all solutions were prepared or diluted with PBS with a pH of 5.8 (0.01 mol / L). The control group A2 was replaced with an equal amount of PBS for sample addition, and the blank sample group A0 was replaced with an equal amount of PBS for enzyme solution addition, with acarbose as the positive control. The α-glucosidase inhibition rate was calculated according to the following formula.

[0038]

[0039] 3. Determination of monosaccharide composition of bitter bamboo shoot polysaccharide:

[0040] Determination by ion chromatography. Take 10 mg of bitter bamboo shoot polysaccharide sample, add 5 mL of 2 mol / L trifluoroacetic acid, and hydrolyze at 100 ° C for 6 hours. The hydrolyzate is dried by vacuum rotary evaporator to remove trifluoroacetic acid, and then 5 mL of methanol solution is added to fully dissolve, and the drying is continued and the above steps are repeated until the sour taste disappears. Dilute the sample with ultrapure water to 25 mL, pass through a 0.22 μm aqueous filter membrane, and obtain the bitter bamboo shoot polysaccharide hydrolyzate, which is then tested and analyzed by ion chromatography.

[0041] Detection conditions: The chromatographic column model is CarboPacTM PA10 (4×250mm); the mobile phases are: phase A: ultrapure water, phase B: 200mmol / L NaOH, phase C: 500mmol / L NaAc, phase D: 20mmol / L NaOH; the flow rate is 1mL / min; the injection volume is 25μL; the column temperature is 30℃.

[0042] 4. Determination of DPPH free radical scavenging rate

[0043] Referring to the determination method of Wang Hongliang et al. (Wang Hongliang, Hui Zhezhe, Liang Ben, et al. Study on the extraction process of polysaccharides from sapodilla leaves and their antioxidant activity [J]. Journal of the Chinese Cereals and Oils Association, 2023, 38(12): 176-182.), 2 mL of 0.1 mmol / L DPPH solution and 2 mL of 0.015625, 0.03125, 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 6, 8, 10 mg / mL bitter bamboo shoot polysaccharide solutions of different concentrations were added to the test tubes in sequence, mixed, and kept in the dark for 30 minutes. The absorbance value was measured at 517 nm and recorded as A1. The bitter bamboo shoot polysaccharide solution and DPPH solution were replaced with anhydrous ethanol, and the above operation was repeated. The absorbance values ​​were measured at 517 nm and recorded as A0 and A2. V C As a positive control, the free radical scavenging rate was calculated according to the following formula.

[0044]

[0045] The preparation method of bitter bamboo shoot pulp in the example is: bitter bamboo shoots are directly mechanically crushed into pulp, namely bitter bamboo shoot pulp.

[0046] In the examples, β-glucosidase was purchased from Jiangsu Duoyang Bioengineering Technology Co., Ltd., and the enzyme activity was 10000 U / g.

[0047] Comparative Example 1

[0048] Weigh 100g of bitter bamboo shoot pulp and add water according to the material-liquid ratio (mass ratio of bitter bamboo shoot pulp to water) of 1:5, 1:10, 1:15 and 1:20, stir evenly, extract in a water bath at 45℃ for 3h, cool to room temperature in an ice bath, centrifuge at 8000r / min for 20min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 70%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 7.84%, 10.72%, 11.65% and 8.03% respectively.

[0049] Example 1

[0050] Weigh 100g of bitter bamboo shoot pulp and add water according to the material-liquid ratio (mass ratio of bitter bamboo shoot pulp to water) of 1:5, 1:10, 1:15 and 1:20, stir evenly, add 1% β-glucosidase (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 45°C for 3h, cool to room temperature in an ice bath, centrifuge at 8000r / min for 20min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 70%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 7.62%, 10.15%, 11.35% and 8.49% respectively.

[0051] It can be seen from the relevant data of Example 1 and Comparative Example 1 that after adding 1% β-glucosidase, the yield of bitter bamboo shoot polysaccharide is slightly reduced.

[0052] Example 2

[0053] Weigh 100g of bitter bamboo shoot pulp, add water according to the material-liquid ratio (mass ratio of bitter bamboo shoot pulp to water) of 1:15, stir evenly, add 3% β-glucosidase (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 35°C, 45°C and 55°C for 3h, cool to room temperature in an ice bath, centrifuge at 7000r / min for 25min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 75%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 8.19%, 10.42% and 9.09% respectively.

[0054] Comparative Example 2

[0055] Weigh 100g of bitter bamboo shoot pulp, add water according to the ratio of 1:15 (mass ratio of bitter bamboo shoot pulp to water), stir evenly, extract in a water bath at 35℃, 45℃ and 55℃ for 3h, cool to room temperature in an ice bath, centrifuge at 7000r / min for 25min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 75%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 8.75%, 11.15% and 9.51% respectively.

[0056] It can be seen from the relevant data of Example 2 and Comparative Example 2 that after adding 3% β-glucosidase, the yield of bitter bamboo shoot polysaccharide is slightly reduced.

[0057] Example 3

[0058] Weigh 100g of bitter bamboo shoot pulp, add water according to the material-liquid ratio (mass ratio of bitter bamboo shoot pulp to water) of 1:15, stir evenly, add 2% β-glucosidase (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 45°C for 2h, 3h and 4h, cool to room temperature in an ice bath, centrifuge at 6000r / min for 30min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 80%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 8.96%, 9.57% and 9.01% respectively.

[0059] Comparative Example 3

[0060] Weigh 100g of bitter bamboo shoot pulp, add water according to the ratio of 1:15 (mass ratio of bitter bamboo shoot pulp to water), stir evenly, extract in a water bath at 45℃ for 2h, 3h and 4h, cool to room temperature in an ice bath, centrifuge at 6000r / min for 30min, add anhydrous ethanol to the obtained supernatant to make the ethanol volume concentration reach 80%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide. The yields of bitter bamboo shoot polysaccharide are 9.75%, 10.25% and 9.43% respectively.

[0061] It can be seen from the relevant data of Example 3 and Comparative Example 3 that after adding 2% β-glucosidase, the yield of bitter bamboo shoot polysaccharide is slightly reduced.

[0062] Example 4

[0063] Weigh 100 g of bitter bamboo shoot pulp, add water according to a solid-liquid ratio of 1:15 (mass ratio of bitter bamboo shoot pulp to water), stir evenly, extract in a water bath at 55°C for 3 h, cool to room temperature in an ice bath, centrifuge at 8,000 r / min for 20 min, add anhydrous ethanol to the supernatant obtained by centrifugation so that the ethanol volume concentration reaches 80%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide No. 1.

[0064] Weigh 100 g of bitter bamboo shoot pulp, add 1500 g of water at a solid-liquid ratio of 1:15 (the mass ratio of bitter bamboo shoot pulp to water), stir evenly, add 1% β-glucosidase (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 55°C for 3 h, cool to room temperature in an ice bath, centrifuge at 8000 r / min for 20 min, add anhydrous ethanol to the supernatant obtained by centrifugation so that the ethanol volume concentration reaches 80%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide No. 2.

[0065] The inhibition rates of bitter bamboo shoot polysaccharides No. 1 and No. 2 prepared in Example 4 on α-glucosidase were further determined.

[0066] Depend on Figure 1 It can be seen that within the concentration range of 0-20 mg / mL, the inhibitory ability of bitter bamboo shoot polysaccharide No. 1 on α-glucosidase slowly increases with the increase of concentration. At 10 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 1 is 35.65%; at 20 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 1 is 40.77%. The α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 2 obtained by adding β-glucosidase is significantly higher than that of bitter bamboo shoot polysaccharide No. 1. Within the concentration range of 0-20 mg / mL, the inhibitory ability of bitter bamboo shoot polysaccharide No. 2 on α-glucosidase also slowly increases with the increase of concentration. At 10 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 1 is 46.98%; at 20 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 1 is 51.48%.

[0067] Example 5

[0068] Weigh 100 g of bitter bamboo shoot pulp, add 1500 g of water at a solid-liquid ratio of 1:15 (mass ratio of bitter bamboo shoot pulp to water), stir evenly, extract in a water bath at 55°C for 3 h, cool to room temperature in an ice bath, centrifuge at 7 000 r / min for 25 min, add anhydrous ethanol to the supernatant obtained by centrifugation so that the ethanol volume concentration reaches 70%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide No. 3.

[0069] Weigh 100 g of bitter bamboo shoot pulp, add 1500 g of water according to a solid-liquid ratio of 1:15 (the mass ratio of bitter bamboo shoot pulp to water), stir evenly, add 2% β-glucosidase (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 55°C for 3 h, cool to room temperature in an ice bath, centrifuge at 7000 r / min for 25 min, add anhydrous ethanol to the supernatant obtained by centrifugation so that the ethanol volume concentration reaches 70%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide No. 4.

[0070] The monosaccharide compositions of bitter bamboo shoot polysaccharide No. 3 and bitter bamboo shoot polysaccharide No. 4 prepared in Example 5 were further determined.

[0071] Bitter bamboo shoot polysaccharide No. 3 is composed of arabinose, galactose, glucose, xylose and galacturonic acid, and the molar ratio of each monosaccharide component is 12.22:17.16:75.96:13.77:1.00; Bitter bamboo shoot polysaccharide No. 4 is composed of arabinose, galactose, glucose, xylose and galacturonic acid, and the molar ratio of each monosaccharide component is 13.79:15.37:64.15:13.16:1.00. It can be seen from the monosaccharide composition of bitter bamboo shoot polysaccharide No. 3 and bitter bamboo shoot polysaccharide No. 4 that bitter bamboo shoot polysaccharide is mainly composed of glucose.

[0072] The DPPH radical scavenging rates of bitter bamboo shoot polysaccharide No. 3 and bitter bamboo shoot polysaccharide No. 4 prepared in Example 5 were further determined, as shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] It can be concluded from Table 1 that within the concentration range of 0.2-4 mg / mL, the scavenging ability of vitamin C on DPPH free radicals remains at about 95%, but the scavenging ability of bitter bamboo shoot polysaccharide No. 3 and bitter bamboo shoot polysaccharide No. 4 on DPPH free radicals increases with the increase of concentration. When the concentration of bitter bamboo shoot polysaccharide is 0.2 mg / mL, the scavenging ability of bitter bamboo shoot polysaccharide No. 3 on DPPH free radicals is 49.81%, and the scavenging ability of bitter bamboo shoot polysaccharide No. 4 on DPPH free radicals is 51.76%, that is, the IC of bitter bamboo shoot polysaccharide No. 4 to scavenging DPPH free radicals is 2.34%. 50The value was lower than 0.2mg / ml, while the IC value of bitter bamboo shoot polysaccharide No. 3 in scavenging DPPH free radicals was 50 The value is higher than 0.2mg / ml. Studies have shown that monosaccharide composition and side chain conformation affect the scavenging effect of polysaccharides on DPPH free radicals. The more glucose connected by 1,6-glycosidic bonds on the side chain and the more arabinose connected by 1,4-glycosidic bonds on the side chain, the higher the DPPH free radical scavenging rate. The content of glucose and arabinose in the monosaccharide composition of bitter bamboo shoot polysaccharide is relatively high, which may be related to the better scavenging effect of bitter bamboo shoot polysaccharide on DPPH free radicals.

[0077] Example 6

[0078] Weigh 100 g of bitter bamboo shoot pulp, add 900 g of water according to a solid-liquid ratio of 1:9 (the mass ratio of bitter bamboo shoot pulp to water), stir evenly, add 1.5% β-glucosidase, or 1.5% glucanase (Angel Enzyme (Yichang) Co., Ltd.), or 1.5% pectinase (Angel Enzyme (Yichang) Co., Ltd.), or 1.5% cellulase (Angel Enzyme (Yichang) Co., Ltd.), or 1.5% AY50C protease (Amano Enzyme (Jiangsu) Co., Ltd.) (based on the weight of bitter bamboo shoot pulp), extract in a water bath at 35°C for 3 h, cool to room temperature in an ice bath, centrifuge at 8,000 r / min for 20 min, add anhydrous ethanol to the supernatant obtained by centrifugation so that the ethanol volume concentration reaches 75%, take the precipitate, and dry it to obtain bitter bamboo shoot polysaccharide No. 5, bitter bamboo shoot polysaccharide No. 6, bitter bamboo shoot polysaccharide No. 7, bitter bamboo shoot polysaccharide No. 8 and bitter bamboo shoot polysaccharide No. 9.

[0079] The inhibition rates of bitter bamboo shoot polysaccharides No. 5, No. 6, No. 7, No. 8 and No. 9 prepared in Example 6 on α-glucosidase were further determined, as shown in Table 2.

[0080] Table 2

[0081]

[0082]

[0083] As shown in Table 2, the inhibitory ability of bitter bamboo shoot polysaccharide No. 5 prepared by adding β-glucosidase on α-glucosidase slowly increases with the increase of concentration. At 5 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 5 is 41.23%; at 15 mg / mL, the α-glucosidase inhibition rate of bitter bamboo shoot polysaccharide No. 5 is 45.59%. At each concentration, bitter bamboo shoot polysaccharide No. 5 is significantly greater than bitter bamboo shoot polysaccharide No. 6, bitter bamboo shoot polysaccharide No. 7, bitter bamboo shoot polysaccharide No. 8 and bitter bamboo shoot polysaccharide No. 9 prepared by other enzyme preparations.

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing bitter bamboo shoot polysaccharide, characterized in that: The steps include: The bitter bamboo shoot pulp is mixed evenly with water, β-glucosidase is added for extraction, and the mixture is centrifuged. Ethanol is added to obtain the supernatant for precipitation, and the precipitate is bitter bamboo shoot polysaccharide.

2. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: The mass ratio of the bitter bamboo shoot slurry to water is 1:5 to 1:

20.

3. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: The extraction temperature is 35-55° C.; the extraction time is 2-4 hours.

4. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: The bitter bamboo shoot pulp is obtained by cutting the bitter bamboo shoots into pieces and crushing them.

5. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: The added amount of the beta-glucosidase is 1%-3% of the weight of the bitter bamboo shoot pulp.

6. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: The centrifugal speed is 6000-8000 r / min; the centrifugal time is 20-30 min.

7. The method for preparing bitter bamboo shoot polysaccharide according to claim 1, characterized in that: After the ethanol is added, the volume concentration of the ethanol is 70-80%.

8. The bitter bamboo shoot polysaccharide prepared by the preparation method according to any one of claims 1 to 7.

9. The bitter bamboo shoot polysaccharide according to claim 8, characterized in that The monosaccharide composition of the bitter bamboo shoot polysaccharide is composed of arabinose, galactose, glucose, xylose and galacturonic acid, and the molar ratio of each monosaccharide component is 10-14:15-19:60-78:12-16:1.

00.

10. Use of the bitter bamboo shoot polysaccharide according to any one of claims 8 to 9 in preparing foods having hypoglycemic or anti-oxidative effects.

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