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CN-121975037-A - Method for extracting duckweed polysaccharide from duckweed with little root

CN121975037ACN 121975037 ACN121975037 ACN 121975037ACN-121975037-A

Abstract

The invention relates to the technical field of plant polysaccharide extraction, in particular to a method for extracting duckweed polysaccharide from duckweed, which comprises the following steps of grinding a duckweed sample, concentrating the concentrated solution under reduced pressure, extracting with water, precipitating with alcohol to obtain a crude water extract, removing pigment, fat and protein, and the like, obtaining duckweed crude polysaccharide, and separating and purifying the extracted duckweed crude polysaccharide by ion exchange chromatography and gel chromatography in the subsequent process to obtain purified duckweed polysaccharide with higher purity and better uniformity. The extraction and separation method has the advantages of simple operation, stable extraction process, higher product purity and the like.

Inventors

  • WEI HUALIN
  • LI JIA
  • FAN QINJIE
  • DING XUANWEN
  • WANG DU

Assignees

  • 河南省食品和盐业检验技术研究院(河南省粮油饲料产品质量监督检验中心)

Dates

Publication Date
20260505
Application Date
20260319

Claims (8)

  1. 1. A method for extracting duckweed polysaccharide from duckweed, which is characterized by comprising the following process steps: S1, taking 500g of dry duckweed raw materials, mechanically grinding, sieving with a 50-70 mesh sieve, immersing the sieved crushed materials into ethanol with the volume fraction of 93-97% at room temperature for 11-13h to remove lipid impurities and fat-soluble pigments, centrifuging with 5500-6500g for 9-11min, and collecting precipitate residues; s2, adding 18-22 times of distilled water into the residue at 55-65 ℃, continuously stirring and extracting for 3.5-4.5h, centrifuging for 9-11min with 5500-6500g, and collecting supernatant extract; S3, repeating the water bath extraction operation of the step S2 once, combining the supernatant extract collected twice, and performing vacuum reduced pressure concentration treatment to obtain concentrated solution; S4, adding 3.5-4.5 times of absolute ethyl alcohol into the concentrated solution to precipitate a crude water extract, and then incubating for 11-13h at the temperature of 3.5-4.5 ℃ to obtain the crude water extract; S5, redissolving the obtained crude water extract in 600-1000ml of distilled water, continuously carrying out deproteinization treatment by adopting a Sevag method, removing lipid by using petroleum ether, carrying out chromatographic decolorization treatment by using macroporous adsorption resin, dialyzing for 22-26h by using distilled water, and freeze-drying to obtain the duckweed crude polysaccharide.
  2. 2. The method for extracting duckweed polysaccharide from duckweed with little root as claimed in claim 1, wherein the duckweed crude polysaccharide obtained in the step S5 is separated and purified by ion exchange chromatography and gel chromatography to finally obtain purified duckweed polysaccharide with higher purity and better uniformity.
  3. 3. The method for extracting duckweed polysaccharide from duckweed with less root, as claimed in claim 1, wherein the purity of the duckweed crude polysaccharide is measured by a sulfuric acid-phenol method, the specific measurement process comprises the steps of weighing about 25mg of duckweed crude polysaccharide solid, adding water for dissolution and dilution, taking 100 mu L of polysaccharide supernatant, adding 600 mu L of sulfuric acid-phenol reagent for uniform mixing, mixing the sulfuric acid-phenol reagent with 5% phenol solution and concentrated sulfuric acid according to a volume ratio of 1:5, standing for 10min in a dark place, measuring a light absorption value at a wavelength of 490nm, and measuring that the purity of the duckweed crude polysaccharide is 42.7%.
  4. 4. The method for extracting duckweed polysaccharide from duckweed, according to claim 1, wherein in the step S1, the duckweed raw material is mechanically ground and then passes through a 60-mesh sieve, and the crushed material after the sieving is immersed in 95% ethanol at room temperature for 12 hours to remove lipid impurities and liposoluble pigments, and is centrifuged at 6000g for 10 minutes.
  5. 5. The method for extracting duckweed polysaccharide from duckweed, according to claim 4, wherein in the step S2, distilled water is added to the residue at a temperature of 60 ℃ in an amount of 20 times by weight, the mixture is continuously stirred and extracted for 4 hours, and the mixture is centrifuged at 6000g for 10 minutes, and the supernatant extract is collected.
  6. 6. The method for extracting duckweed polysaccharide from duckweed parviflora according to claim 5, wherein in the step S4, 4 times the volume of absolute ethanol is added to the concentrated solution to precipitate the crude aqueous extract, and then the crude aqueous extract is obtained by incubating for 12 hours at a temperature of 4 ℃.
  7. 7. The method for extracting duckweed polysaccharide from duckweed with little root as claimed in claim 6, wherein in the step S5, the reagent used by the Sevag method is prepared from chloroform and n-butanol with a volume ratio of 4:1, the material model of the macroporous adsorption resin is AB-8 type, and the dialysis time of distilled water is 24 hours.
  8. 8. The method for extracting duckweed polysaccharide from duckweed parviflora according to claim 7, wherein in the step S5, the petroleum ether is used in an amount of 50ml each time, 3 times, and the distilled water is dialyzed with a dry dialysis bag having MWCO of 3 kDa.

Description

Method for extracting duckweed polysaccharide from duckweed with little root Technical Field The invention relates to the technical field of plant polysaccharide extraction, in particular to a method for extracting duckweed polysaccharide from duckweed with little root. Background Polysaccharide (polysaccharide) is a long-chain polymer composed of a plurality of monosaccharide molecules connected with each other through glycosidic bonds, and is a very important macromolecular substance in cells. Polysaccharides consisting of the same monosaccharides are called homopolysaccharides, such as starch, cellulose and glycogen, polysaccharides consisting of different monosaccharides are called heteropolysaccharides, such as acacia is composed of pentoses and galactose, etc. Polysaccharides have a polyhydroxy aldehyde or polyhydroxy ketone structure and are typically dispersible in aqueous solutions, but insoluble in ethanol. The extraction and separation methods are similar, and mainly utilize the characteristic that polysaccharide is dissolved in hot water or acid, alkali and salt solution but not dissolved in organic solvents such as alcohol, ether, acetone and the like for extraction. The aquatic plant duckweed is a generic term of duckweed family plants, and has simple structure and highly degenerated morphology. Duckweed is the smallest flowering quilt plant in the world and belongs to a light energy autotrophic plant, and comprises 5 genera, namely duckweed (Lemna), duckweed (Spirodela), duckweed (Landoltia), duckweed (Wolffia) and duckweed (Wolfield), 38 species and all over the world. Researches show that the duckweed has rich nutrition, the whole duckweed contains rich fatty acids (mainly linolenic acid, palmitic acid, linoleic acid and the like) and rich nutritional ingredients such as proteins, and the duckweed has rich dietary fibers and high nutritional value. At present, small-particle starch, protein, flavone and other nutritional active ingredients in duckweed become hot spots for duckweed research, and in order to further define the material basis of the duckweed health care effect, the research of extraction and separation of duckweed polysaccharide is started, and a certain effect is achieved. The existing extraction methods of duckweed polysaccharide reported in China mainly comprise an alcohol precipitation method, a heap heating method, an ultrasonic method, an ultrafiltration method and the like, and most of the extraction methods analyze the duckweed polysaccharide from the two aspects of purity and yield of crude polysaccharide. The extraction process research of duckweed polysaccharide is optimized by PB test combined with BBD response surface method, such as Jiang Zheng, and the yield of crude polysaccharide is 3.36%. Nie Guangjun and the like, and extracting crude polysaccharide by using an 80 ℃ hot water leaching microorganism fermentation heap heating method, wherein the yield is 0.19 percent, and the purity is 18.2 percent. Yu Zhongna, etc., the extract is treated by ultrasonic wave, and crude polysaccharide is obtained after ethanol precipitation, the yield is 1.125%, and the purity is 18.03%. Zhou Jing and other membrane filtration treatment, and trichloroacetic acid deproteinization, ethanol precipitation and other treatment to obtain crude polysaccharide with yield of 0.08% and purity of 53.5%. The duckweed polysaccharide obtained by the above-mentioned process method has lower yield, so that the production cost is increased, the purity of the product is reduced, the resource waste is easy to cause, and the like. Therefore, development of a more excellent and efficient duckweed polysaccharide extraction method is needed. Disclosure of Invention The invention aims to provide a method for extracting duckweed polysaccharide from duckweed with less roots, which has the advantages of simple operation, stable extraction process, higher product purity and the like by optimizing and improving the extraction process of the duckweed polysaccharide in the duckweed with less roots, and solves the problem of effective utilization of duckweed resources. In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for extracting duckweed polysaccharide from duckweed comprises the following process steps: S1, taking 500g of dry duckweed raw materials, mechanically grinding, sieving with a 50-70 mesh sieve, immersing the sieved crushed materials into ethanol with the volume fraction of 93-97% at room temperature for 11-13h to remove lipid impurities and fat-soluble pigments, centrifuging with 5500-6500g for 9-11min, and collecting precipitate residues; s2, adding 18-22 times of distilled water into the residue at 55-65 ℃, continuously stirring and extracting for 3.5-4.5h, centrifuging for 9-11min with 5500-6500g, and collecting supernatant extract; S3, repeating the water bath extraction operation of the step S2 once, combining the supernatant extrac