Method for extracting and purifying Dendrobium officinale polysaccharides

Patent metadata

Field	Value
Publication number	US-11780936-B2
Application number	US-202017010808-A
Country	US
Kind code	B2
Filing date	Sep 2, 2020
Priority date	Apr 25, 2020
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

A method for extracting and purifying Dendrobium officinale polysaccharides comprises following steps: (1) fully disperse Dendrobium officinale powder in pure water to obtain crude liquid; (2) removing insoluble impurities from the crude liquid through a microfiltration membrane to obtain permeate 1 and retentate 1; (3) performing macroporous ultrafiltration treatment of the permeate 1 and collect permeate 2 and retentate 2; (4) adding an aqueous solution of edible alkali metal inorganic salt to the retentate 2, fully stirring and dissolving to obtain polysaccharide crude liquid, performing macroporous ultrafiltration treatment and collecting permeate 3 and retentate 3; (5) combining the permeate 2 and permeate 3, adding the combined permeate into an electrodialysis device for desalination, and collecting dilute solution and concentrated solution; (6) performing microporous ultrafiltration treatment of the dilute solution and collect retentate 4 and permeate 4; (7) carrying out freeze-drying of the retentate 4 to obtain Dendrobium officinale polysaccharides.

First claim

The invention claimed is:

1. A method for extracting and purifying Dendrobium officinale polysaccharides, comprising following steps:
(1) taking Dendrobium officinale powder and fully dispersing it in pure water to obtain crude liquid;
(2) removing insoluble impurities from the crude liquid obtained in the step (1) through a microfiltration membrane to obtain permeate 1 and retentate 1;
(3) performing ultrafiltration treatment of the permeate 1 collected in the step (2) through a macroporous ultrafiltration membrane with a molecular weight cut-off of 100-800 kDa, and collecting permeate 2 and retentate 2;
(4) adding 0.5-1.5 mol/L of aqueous solution of edible alkali metal inorganic salt to the retentate 2 collected in the step (3), stirring and fully dissolving to obtain polysaccharide crude liquid, performing ultrafiltration treatment through a macroporous ultrafiltration membrane with a molecular weight cut-off of 100-800 kDa, and collecting permeate 3 and retentate 3;
(5) combining the permeate 2 and permeate 3 obtained in the step (3) and step (4), adding the combined permeate into an electrodialysis device for desalination, and collecting dilute solution and concentrated solution;
(6) performing ultrafiltration treatment of the dilute solution obtained in the step (5) through an ultrafiltration membrane with a molecular weight cut-off of 3 kDa-8 kDa and collecting retentate 4 and permeate 4;
(7) carrying out freeze-drying of the retentate 4 obtained in the step (6) to obtain Dendrobium officinale polysaccharides.

2. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein the concentration of Dendrobium officinale in the crude liquid is 10-30 wt %.

3. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein conditions of the microfiltration membrane treatment are as follows: operating temperature is 25-50° C., transmembrane pressure is 0.3-0.6 MPa, flow rate of feed liquid is 0.2-0.5 L/min.

4. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein in the steps (3) and (4), the molecular weight cut-off of the macroporous ultrafiltration membrane is 300-800 kDa.

5. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 4 , wherein in the steps (3) and (4), the molecular weight cut-off of the macroporous ultrafiltration membrane is 500 kDa.

6. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein conditions of the ultrafiltration treatment are as follows: operating temperature is 25-50° C., transmembrane pressure is 0.3-0.6 MPa, flow rate of feed liquid is 0.2-0.5 L/min.

7. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein in the step (4), the edible alkali metal inorganic salt is one of NaCl, Na 2 SO 4 , KCl, K 2 SO 4 or a mixture thereof.

8. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein the aqueous solution of the edible alkali metal inorganic salt is 0.5-1.5 M NaCl aqueous solution or 0.5-1M Na 2 SO 4 aqueous solution.

9. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 8 , wherein the aqueous solution of the edible alkali metal inorganic salt is 0.5M NaCl aqueous solution or 0.5M Na 2 SO 4 aqueous solution.

10. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein conditions of the ultrafiltration treatment are as follows: pH of feed liquid is 4-10, operating temperature is 25-50° C., transmembrane pressure is 0.3-0.6 MPa, and flow rate of feed liquid is 0.2-0.5 L/min.

11. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 10 , wherein in the step (4), the conditions of the ultrafiltration treatment are as follows: pH of the feed liquid is 6-7, operating temperature is 30-35° C., and flow rate of feed liquid is 0.2-0.5 L/min.

12. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein in the step (6), the molecular weight cut-off of the ultrafiltration membrane is 3-5 kDa.

13. The method for extracting and purifying Dendrobium officinale polysaccharides according to claim 1 , wherein in the step (6), the molecular weight cut-off of the ultrafiltration membrane is 5 kDa.

Assignees

• Univ Zhejiang Technology

Inventors

• Shao Ping
• Qian Peiyu
• Pan Jiefeng
• Sun Peilong

Classifications

• B01D61/423

  comprising multiple electrodialysis steps · CPC title

• B01D61/149

  Multistep processes comprising different kinds of membrane processes selected from ultrafiltration or microfiltration · CPC title

• C08B37/0003 Primary

  General processes for their isolation or fractionation, e.g. purification or extraction from biomass · CPC title

• B01D61/145

  Ultrafiltration · CPC title

• B01D61/146

  comprising multiple ultrafiltration steps · CPC title