Method for simultaneously extracting dietary fiber and oligosaccharide from beet pulp

Abstract

The invention relates to a method for simultaneously extracting dietary fiber and oligosaccharide from beet pulp, which comprises the following steps: mixing pretreated beet pulp with water, extracting, filtering to obtain a first filter residue and a first supernatant, mixing the first filter residue with alkali, and centrifuging to obtain a second filter residue and a second supernatant; mixing the second filter residue with an acid, and centrifuging to obtain a third filter residue and a third supernatant; mixing the third filter residue with an enzyme for enzymolysis, and centrifuging to obtain a fourth filter residue and a fourth supernate; mixing all the supernatants, performing ultrafiltration concentration to obtain a concentrated solution with the molecular weight of 500-10kDa, and performing freeze drying to obtain oligosaccharide; the concentrated solution with the molecular weight larger than 10 kDa is subjected to ethanol precipitation, and soluble dietary fibers are obtained; and mixing the fourth filter residue with a hydrogen peroxide solution, boiling, and filtering to obtain a precipitate which is the insoluble dietary fiber. According to the method, three substances are simultaneously extracted in one technological process, so that resources are comprehensively utilized, and the extraction efficiency is maximized.

Description

Technical Field

[0001] The invention belongs to the technical field of material extraction and relates to a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp. Background Art

[0002] Beet pulp is the shredded beets with little sugar after they are shredded and fully extracted from the sugar beets during the sugar production process. It is also called waste pulp, commonly known as beet residue. Except for a small amount used in the feed industry, most of the beet pulp has no appropriate use, has low economic benefits, and also causes environmental pollution and waste of resources.

[0003] Patent CN103266150B provides a method for preparing functional oligosaccharides from beet pulp, and the oligosaccharide content is above 85%. Patent CN104886547B discloses an extraction method using a decolorization pretreatment-drying-ultrafine grinding method, which further optimizes the color, dietary fiber content, water holding capacity and oil holding capacity of the extracted beet dietary fiber powder.

[0004] The existing technologies focus on the extraction of sugar beet pulp oligosaccharides and insoluble dietary fiber respectively. While extracting the target products, other functional components are discarded, which to a certain extent fails to achieve the purpose of efficient utilization of sugar beet pulp resources. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, the extraction method comprising:

[0008] (1) subjecting beet pulp to plasma treatment, and then subjecting it to ultrafine grinding, and subjecting the obtained powder to magnetic separation for impurity removal;

[0009] (2) mixing the crushed beet pulp with water, extracting and filtering to obtain a first filter residue and a first supernatant, mixing the first filter residue with alkali, and centrifuging to obtain a second filter residue and a second supernatant;

[0010] (3) mixing the second filter residue with an acid and centrifuging to obtain a third filter residue and a third supernatant;

[0011] (4) mixing the third filter residue with the enzyme solution for enzymolysis, and centrifuging to obtain a fourth filter residue and a fourth supernatant;

[0012] (5) mixing the first supernatant, the second supernatant, the third supernatant and the fourth supernatant, concentrating by ultrafiltration, freeze-drying the concentrate with a molecular weight of 500-10 kDa to obtain oligosaccharides; and precipitating the concentrate with a molecular weight greater than 10 kDa by ethanol to obtain soluble dietary fiber;

[0013] The fourth filter residue is mixed with hydrogen peroxide solution, and filtered after boiling, and the precipitate is the insoluble dietary fiber.

[0014] The present application simultaneously separates insoluble dietary fiber, soluble dietary fiber and oligosaccharides in one preparation process. The yield of soluble dietary fiber from beet pulp is greatly improved, the method is mild, and food-grade reagents are used. Among them, components below 500 kDa are evaporated and condensed to form circulating water for the next round of dietary fiber component separation; the ethanol solution involved in the preparation process can also be separated by evaporation and condensation, and the obtained ethanol is used for the next round of dietary fiber component separation, saving preparation costs.

[0015] Preferably, the power of the plasma treatment is 100-400 W, and the time is 50-150 s.

[0016] The power can be selected as 100W, 120W, 150W, 180W, 200W, 220W, 250W, 280W, 300W, 320W, 350W, 380W, 400W, etc. The time can be selected as 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, etc. Other specific point values ​​within the above numerical range can be selected, so they will not be elaborated here.

[0017] Preferably, the impurity removal includes removing ferromagnetic impurities.

[0018] Preferably, step (1) further comprises drying the beet pulp before plasma treatment.

[0019] Preferably, the particle size of the beet pulp in step (2) is 10-50 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc. Other specific point values ​​within the above numerical range can be selected and will not be described here one by one.

[0020] Preferably, the temperature for extraction by mixing with water is 80-100°C and the time is 1-3h.

[0021] The temperature can be selected as 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, etc., and the time can be selected as 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, etc. Other specific point values ​​within the above numerical range can be selected, so they will not be elaborated here one by one.

[0022] Preferably, the base comprises sodium hydroxide.

[0023] Preferably, the acid comprises citric acid.

[0024] Preferably, the pH of the mixture with the base is 8-10 and the mixing time is 30-60 min.

[0025] The pH can be selected from 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10, etc., and the time can be selected from 30min, 32min, 35min, 38min, 40min, 42min, 45min, 48min, 50min, 52min, 55min, 58min, 60min, etc. Other specific point values ​​within the above numerical range can be selected, so they will not be described one by one here.

[0026] Preferably, the pH of the mixture with the acid is 2-4 and the mixing time is 30-60 min.

[0027] The pH can be selected from 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, etc., and the time can be selected from 30min, 32min, 35min, 38min, 40min, 42min, 45min, 48min, 50min, 52min, 55min, 58min, 60min, etc. Other specific point values ​​within the above numerical range can be selected, so they will not be described one by one here.

[0028] Preferably, the enzymes include cellulases, hemicellulases and pectinases.

[0029] Preferably, the enzyme activity ratio of the cellulase, hemicellulase and pectinase is (0.5-1):(10-20):(5-10).

[0030] Among them, the specific point values ​​in (0.5-1) can be selected from 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., the specific point values ​​in (10-20) can be selected from 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc., the specific point values ​​in (5-10) can be selected from 5, 6, 7, 8, 9, 10, etc., and other specific point values ​​within the above numerical range can be selected, so they will not be listed here one by one.

[0031] Preferably, the temperature for mixing with the enzyme is 50-60°C, the pH is 4.5-6.5, and the time is 1-2 hours.

[0032] The temperature can be selected from 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, etc., the pH can be selected from 4.5, 4.7, 4.9, 5.1, 5.3, 5.5, 5.7, 5.9, 6.1, 6.3, 6.5, etc., the time can be selected from 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, etc., and other specific point values ​​within the above numerical range can be selected, so they will not be described one by one here.

[0033] Preferably, the ratio of filter residue to enzyme solution is 1 g: (10-20) mL.

[0034] The specific point values ​​in (10-20) can be selected as 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. Other specific point values ​​within the above numerical range can be selected, and they will not be described one by one here.

[0035] Preferably, the concentration of the enzyme in the enzyme solution is 1000-40000 U / mL, for example 1000 U / mL, 3000 U / mL, 5000 U / mL, 8000 U / mL, 10000 U / mL, 15000 U / mL, 20000 U / mL, 25000 U / mL, 30000 U / mL, 35000 U / mL, 40000 U / mL, etc. Other specific points within the above numerical range can be selected, which will not be described one by one here.

[0036] Preferably, steps (2) to (4) are performed under ultrasonic conditions.

[0037] Preferably, the power of the ultrasound is 200-240W, for example 200W, 205W, 210W, 215W, 220W, 225W, 230W, 235W, 240W, etc. Other specific point values ​​within the above numerical range can be selected, which will not be described here one by one.

[0038] Preferably, the ethanol precipitation in step (5) includes a primary ethanol precipitation and a secondary ethanol precipitation.

[0039] Preferably, the final concentration of ethanol in one ethanol precipitation is 68-72%, for example 68%, 69%, 70%, 71%, 72%, etc. Other specific values ​​within the above numerical range can be selected and will not be described one by one here.

[0040] Preferably, the final concentration of ethanol in the secondary ethanol precipitation is 75-85%, for example 75%, 76%, 77%, 78%, 9%, 80%, 81%, 82%, 83%, 84%, 85%, etc. Other specific points within the above numerical range can be selected and will not be described here one by one.

[0041] Preferably, the ratio of the fourth filter residue to hydrogen peroxide is (0.5-1) g: (5-10) mL.

[0042] The specific point values ​​in (0.5-1) can be selected as 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., and the specific point values ​​in (5-10) can be selected as 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, etc. Other specific point values ​​within the above numerical range can be selected, and they will not be listed here one by one.

[0043] Preferably, the mass percentage of hydrogen peroxide in the hydrogen peroxide solution is 3-8%, for example 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, etc. Other specific values ​​within the above numerical range can be selected, which will not be repeated here.

[0044] Preferably, the temperature for mixing with hydrogen peroxide is 50-60°C and the time is 0.5-1 h.

[0045] The temperature can be selected as 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, etc., and the time can be selected as 0.5h, 0.55h, 0.6h, 0.65h, 0.7h, 0.75h, 0.8h, 0.85h, 0.9h, 0.95h, 1h, etc. Other specific point values ​​within the above numerical range can be selected, so they will not be elaborated here.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present application separates insoluble dietary fiber, soluble dietary fiber and oligosaccharides simultaneously in one preparation process, greatly improving the yield of soluble dietary fiber from beet pulp; the method is mild and all food-grade reagents are used. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is the extraction flow chart.

[0049] Figure 2 This is the result of SEM observation of the morphology of the beet pulp obtained in Preparation Example 1.

[0050] Figure 3 This is the result of SEM observation of the morphology of the beet pulp obtained in Preparation Example 2.

[0051] Figure 4 This is the result of SEM observation of the morphology of the beet pulp obtained in Preparation Example 3.

[0052] Figure 5 This is the scanning electron microscope observation result of the apparent morphology of the beet pulp obtained in Comparative Preparation Example 1. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] The sources of the functional ingredients contained in the products involved in the following embodiments and comparative examples are as follows (only the functional ingredients are reflected, and the necessary auxiliary ingredients contained in other commercially available raw materials are not repeated):

[0055] Cellulase is a product purchased from MACKLIN under the trade name of Cellulase;

[0056] Hemicellulase is a product purchased from Solarbio under the trade name of hemicellulase;

[0057] Pectinase was purchased from Solarbio with the trade name of Pectinase.

[0058] Preparation Example 1

[0059] This preparation example provides a method for processing beet pulp, the method comprising:

[0060] (1) Drying the beet pulp, placing the beet pulp in a plasma generator, and treating it at 400 W for 100 s;

[0061] (2) The beet pulp treated with plasma is crushed, and ferromagnetic impurities in the beet pulp are removed using magnetic separation equipment.

[0062] The morphology of beet pulp after plasma treatment is shown in the figure below. Figure 2 shown.

[0063] Preparation Example 2

[0064] This preparation example provides a method for processing beet pulp, the method comprising:

[0065] (1) Drying the beet pulp, placing the beet pulp in a plasma generator, and treating it at 400 W for 50 seconds;

[0066] (2) The beet pulp treated with plasma is crushed, and ferromagnetic impurities in the beet pulp are removed using magnetic separation equipment.

[0067] The morphology of beet pulp after plasma treatment is shown in the figure below. Figure 3 shown.

[0068] Preparation Example 3

[0069] This preparation example provides a method for processing beet pulp, the method comprising:

[0070] (1) Drying the beet pulp, placing the beet pulp in a plasma generator, and treating it at 400 W for 150 s;

[0071] (2) The beet pulp treated with plasma is crushed, and ferromagnetic impurities in the beet pulp are removed using magnetic separation equipment.

[0072] The morphology of beet pulp after plasma treatment is shown in the figure below. Figure 4 shown.

[0073] Comparative Preparation Example 1

[0074] This comparative preparation example provides a method for processing beet pulp, the method comprising:

[0075] The beet pulp is dried and crushed, and magnetic separation equipment is used to remove ferromagnetic impurities in the beet pulp.

[0076] The appearance of beet pulp is shown in the figure Figure 5 shown.

[0077] Example 1

[0078] This embodiment provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp. Figure 1 , the method comprising:

[0079] (1) Ultrafinely pulverizing the beet pulp obtained in Preparation Example 1 to a particle size of about 30 μm;

[0080] (2) mixing the crushed beet pulp with water, extracting at 90° C. for 2 h, and filtering, using 220W ultrasonic treatment during the extraction process to obtain a first filter residue and a first supernatant, mixing the first filter residue with sodium hydroxide, adjusting the pH to 9, centrifuging for 30 min, and obtaining a second filter residue and a second supernatant;

[0081] (3) mixing the second filter residue with citric acid, adjusting the pH to 3 for 30 min, performing ultrasonic treatment at 220 W during the mixing process, and centrifuging to obtain a third filter residue and a third supernatant;

[0082] (4) mixing the third filter residue with an enzyme solution for enzymolysis at 55° C. for 1.5 h, with a pH of 5.5, a ratio of the filter residue to the enzyme solution of 1 g:15 mL, an enzyme concentration of 30,000 U / mL, the enzymes comprising cellulase, hemicellulase and pectinase with an enzyme activity ratio of 1:20:10, performing ultrasonic treatment at 220 W during the enzymolysis process, and centrifuging to obtain a fourth filter residue and a fourth supernatant;

[0083] (5) The first supernatant, the second supernatant, the third supernatant and the fourth supernatant are mixed, ultrafiltered and concentrated, and a concentrated solution with a molecular weight of 500-10 kDa is obtained. The ultrafiltered concentrated solution is eluted with pure water to remove salt and small molecular impurities, and freeze-dried to obtain oligosaccharides; the concentrated solution with a molecular weight greater than 10 kDa is precipitated with ethanol twice, wherein the final concentration of ethanol in the first ethanol precipitation is 70% and the final concentration of ethanol in the second ethanol precipitation is 80%, and the precipitation is to obtain soluble dietary fiber;

[0084] The fourth filter residue was mixed with 5% hydrogen peroxide solution at 55° C. for 1 hour, the ratio of the fourth filter residue to the hydrogen peroxide solution being 1 g / 8 mL, and then filtered after boiling, and the precipitate was the insoluble dietary fiber.

[0085] Example 2

[0086] This embodiment provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp. Figure 1 , the method comprising:

[0087] (1) Ultrafinely grinding the beet pulp obtained in Preparation Example 1 to a particle size of about 10 μm;

[0088] (2) mixing the crushed beet pulp with water, extracting at 80° C. for 3 h, and filtering, using 200W ultrasonic treatment during the extraction process to obtain a first filter residue and a first supernatant, mixing the first filter residue with sodium hydroxide, adjusting the pH to 8, centrifuging for 60 min, and obtaining a second filter residue and a second supernatant;

[0089] (3) mixing the second filter residue with citric acid, adjusting the pH to 2 for 45 min, performing ultrasonic treatment at 200 W during the mixing process, and centrifuging to obtain a third filter residue and a third supernatant;

[0090] (4) mixing the third filter residue with an enzyme solution at 50° C. for 2 h, with a pH of 4.5, the ratio of the filter residue to the enzyme solution being 1 g:20 mL, the concentration of the enzyme in the enzyme solution being 20,000 U / mL, the enzyme comprising cellulase, hemicellulase and pectinase with an enzyme activity ratio of 0.5:10:10, ultrasonically treating at 200 W during the enzymolysis process, and centrifuging to obtain a fourth filter residue and a fourth supernatant;

[0091] (5) mixing the first supernatant, the second supernatant, the third supernatant and the fourth supernatant, ultrafiltration and concentration, obtaining a concentrate with a molecular weight of 500-10 kDa, eluting the ultrafiltration concentrate with pure water to remove salt and small molecular impurities, freeze-drying, and obtaining oligosaccharides; the concentrate with a molecular weight greater than 10 kDa is precipitated with ethanol twice, wherein the final concentration of ethanol in the first ethanol precipitation is 72%, and the final concentration of ethanol in the second ethanol precipitation is 85%, and the precipitation is to obtain soluble dietary fiber;

[0092] The fourth filter residue was mixed with 8% hydrogen peroxide solution at 60° C. for 0.5 h, with the ratio of the fourth filter residue to the hydrogen peroxide solution being 1 g / 10 mL. After boiling, the mixture was filtered, and the precipitate was the insoluble dietary fiber.

[0093] Example 3

[0094] This embodiment provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp. Figure 1 , the method comprising:

[0095] (1) Ultrafinely pulverizing the beet pulp obtained in Preparation Example 1 to a particle size of about 50 μm;

[0096] (2) mixing the crushed beet pulp with water, extracting at 100° C. for 1 h, and filtering, using 240W ultrasonic treatment during the extraction process to obtain a first filter residue and a first supernatant, mixing the first filter residue with sodium hydroxide, adjusting the pH to 10, centrifuging for 45 min, and obtaining a second filter residue and a second supernatant;

[0097] (3) mixing the second filter residue with citric acid, adjusting the pH to 4 for 60 min, performing ultrasonic treatment at 240 W during the mixing process, and centrifuging to obtain a third filter residue and a third supernatant;

[0098] (4) mixing the third filter residue with an enzyme solution at 60° C. for 1 h, with a pH of 6, a ratio of the filter residue to the enzyme solution of 1 g:10 mL, an enzyme concentration of 40,000 U / mL, the enzymes comprising cellulase, hemicellulase and pectinase at an enzyme activity ratio of 1:10:10, performing ultrasonic treatment at 240 W during the enzymolysis process, and centrifuging to obtain a fourth filter residue and a fourth supernatant;

[0099] (5) mixing the first supernatant, the second supernatant, the third supernatant and the fourth supernatant, concentrating by ultrafiltration, obtaining a concentrate with a molecular weight of 500-10 kDa, eluting the ultrafiltration concentrate with pure water to remove salt and small molecular impurities, and freeze-drying to obtain oligosaccharides; the concentrate with a molecular weight greater than 10 kDa is precipitated with ethanol twice, wherein the final concentration of ethanol in the first ethanol precipitation is 68% and the final concentration of ethanol in the second ethanol precipitation is 75%, and the precipitation is to obtain soluble dietary fiber;

[0100] The fourth filter residue was mixed with 3% hydrogen peroxide solution at 50° C. for 0.8 h, with the ratio of the fourth filter residue to the hydrogen peroxide solution being 1 g / 5 mL. After boiling, the mixture was filtered, and the precipitate was the insoluble dietary fiber.

[0101] Comparative Example 1

[0102] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (1) is "ultrafinely grinding the beet pulp obtained in Comparative Preparation Example 1 to a particle size of about 30 μm", and other operations remain unchanged.

[0103] Comparative Example 2

[0104] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (1) is "crushing the beet pulp obtained in Preparation Example 1 to a particle size of about 850 μm", and other operations remain unchanged.

[0105] Comparative Example 3

[0106] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (1) is "crushing the beet pulp obtained in Comparative Preparation Example 1 to a particle size of about 850 μm", and other operations remain unchanged.

[0107] Comparative Example 4

[0108] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (3) is not included, the time of alkali treatment in step (2) is extended to 60 minutes, and other operations remain unchanged.

[0109] Comparative Example 5

[0110] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (4) is not included, and other operations remain unchanged.

[0111] Comparative Example 6

[0112] This comparative example provides a method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, which differs from Example 1 only in that step (2) is "mixing the crushed beet pulp with water, extracting at 90° C. for 2 h and then filtering, and using 220 W ultrasonic treatment during the extraction process to obtain a first filter residue and a first supernatant", and the time of acid treatment in step (3) is extended to 60 min, and other operations remain unchanged.

[0113] Test Example 1

[0114] This test example tests the contents of the obtained soluble dietary fiber, insoluble dietary fiber and oligosaccharides.

[0115] Test method: The prepared soluble dietary fiber, insoluble dietary fiber and oligosaccharides are dried and weighed respectively.

[0116]

[0117] Table 1

[0118] Soluble dietary fiber (%) Insoluble dietary fiber (%) Oligosaccharides (%) Example 1 53.17 34.27 8.43 Example 2 52.95 35.61 8.25 Example 3 52.69 35.17 8.39 Comparative Example 1 39.61 50.89 5.69 Comparative Example 2 37.85 51.32 5.36 Comparative Example 3 30.32 59.87 5.13 Comparative Example 4 26.47 61.95 6.30 Comparative Example 5 42.76 48.23 3.86 Comparative Example 6 48.55 37.91 7.41

[0119] It can be seen from the data in Table 1 that the specific preparation method of the present invention has a high extraction rate for soluble dietary fiber, insoluble dietary fiber and oligosaccharides, and can promote the conversion into soluble dietary fiber.

[0120] The applicant declares that the present invention uses the above-mentioned embodiment to illustrate a method of extracting dietary fiber and oligosaccharides from beet pulp at the same time, but the present invention is not limited to the above-mentioned embodiment, that is, it does not mean that the present invention must rely on the above-mentioned embodiment to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary ingredients, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0121] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0122] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp, characterized in that: The method comprises: (1) subjecting beet pulp to plasma treatment, and then subjecting it to ultrafine grinding, and subjecting the obtained powder to magnetic separation for impurity removal; (2) mixing the crushed beet pulp with water, extracting and filtering to obtain a first filter residue and a first supernatant, mixing the first filter residue with alkali, and centrifuging to obtain a second filter residue and a second supernatant; (3) mixing the second filter residue with an acid and centrifuging to obtain a third filter residue and a third supernatant; (4) mixing the third filter residue with the enzyme solution for enzymolysis, and centrifuging to obtain a fourth filter residue and a fourth supernatant; (5) mixing the first supernatant, the second supernatant, the third supernatant and the fourth supernatant, concentrating by ultrafiltration, freeze-drying the concentrate with a molecular weight of 500-10 kDa to obtain oligosaccharides; and precipitating the concentrate with a molecular weight greater than 10 kDa by ethanol to obtain soluble dietary fiber; The fourth filter residue is mixed with hydrogen peroxide solution, and filtered after boiling, and the precipitate is the insoluble dietary fiber.

2. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to claim 1, characterized in that: The power of the plasma treatment is 100-400W, and the time is 50-150s; Preferably, the impurity removal includes removing ferromagnetic impurities; Preferably, step (1) further comprises drying the beet pulp before plasma treatment.

3. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to claim 1 or 2, characterized in that: The particle size of the beet pulp in step (2) is 10-50 μm.

4. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 3, characterized in that: The temperature for extraction when mixed with water is 80-100°C and the time is 1-3h.

5. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 4, characterized in that: The base includes sodium hydroxide; Preferably, the acid comprises citric acid; Preferably, the pH of the mixture with the base is 8-10 and the time is 30-60 min; Preferably, the pH of the mixture with the acid is 2-4 and the mixing time is 30-60 min.

6. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 5, characterized in that: The enzymes include cellulases, hemicellulases and pectinases; Preferably, the enzyme activity ratio of the cellulase, hemicellulase and pectinase is (0.5-1):(10-20):(5-10) ； Preferably, the temperature for mixing with the enzyme solution is 50-60°C, the pH is 4.5-6.5, and the time is 1-2 hours.

7. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 6, characterized in that: The ratio of filter residue to enzyme solution is 1 g: (10-20) mL; Preferably, the concentration of the enzyme in the enzyme solution is 1000-40000 U / mL.

8. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 7, characterized in that: Steps (2) to (4) are performed under ultrasonic conditions; Preferably, the power of the ultrasound is independently 200-240W.

9. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 8, characterized in that: The ethanol precipitation in step (5) includes a primary ethanol precipitation and a secondary ethanol precipitation; Preferably, the final concentration of ethanol in one ethanol precipitation is 68-72%; Preferably, the final concentration of ethanol in the secondary ethanol precipitation is 75-85%.

10. The method for simultaneously extracting dietary fiber and oligosaccharides from beet pulp according to any one of claims 1 to 9, characterized in that: The ratio of the fourth filter residue to the hydrogen peroxide solution is (0.5-1) g: (5-10) mL; Preferably, the mass percentage of hydrogen peroxide in the hydrogen peroxide solution is 3-8%; Preferably, the temperature for mixing with hydrogen peroxide is 50-60°C and the time is 0.5-1 h.

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