Method for preparing tea polysaccharides by combining separating membranes with chromatographic column

Abstract

The invention discloses a method for preparing tea polysaccharides by combining separating membranes with a chromatographic column. The method comprises the steps that water or ethyl alcohol is added in fresh tea for reflux extraction to obtain an extracting solution; the extracting solution is processed with the separating membrane with the molecular weight of 50000 Da to obtain a retaining solution I and a permeating solution I; the permeating solution I is separated through the separating membrane with the molecular weight of 5000 Da to obtain a retaining solution II, the retaining solution I and the retaining solution II are merged, purified water is added in a mixed retaining solution, and separating is performed with the separating membrane with the molecular weight of 5000 Da for three times to obtain a retaining solution III; after the pH is regulated, the temperature is increased to 45 DEG C, heat preservation is performed, the retaining solution III is added in the D101 macroporous resin chromatographic column, and an upper-column effluent solution and a washing solution are collected and merged to obtain a merged solution; concentrating is performed with a nanofiltration membrane, drying is performed, and then the tea polysaccharides are obtained. The method is simple in technology, easy to operate, economical in energy, environmentally friendly, low in energy consumption, free of organic solvent, green, environmentally friendly and high in technological extraction ratio; the prepared tea polysaccharides are high in purity, free of heavy metal and solvent residues and suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of plant purification, and in particular relates to a method for preparing tea polysaccharide by combining a separation membrane with a chromatographic column. Background technique [0002] At present, the commonly used separation process of tea polysaccharide is ethanol precipitation method. Generally, the extract is concentrated under reduced pressure to 1 / 5, and 3 times the amount of absolute ethanol is added to the concentrated solution to make the alcohol content reach more than 75%, and alcohol precipitation is carried out, and it is filtered after standing for 4 to 6 hours. The filter cake is the crude tea polysaccharide , further decolorization and deproteinization, that is, tea polysaccharide boutique. [0003] Commonly used tea polysaccharide decolorization methods include activated carbon method, hydrogen peroxide method, cetyltrimethylammonium bromide-n-hexanol-isooctane method. Deproteinizatio...

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Problems solved by technology

[0004] However, the preparation of crude tea polysaccharides by alcohol precipitation method is tedious, the whole separation process is cumbersome, the amount of solvent is large, the separation period is long, and the production cost is high.

[0005] Activated carbon decolorization, activated carbon has a large adsorption of tea polysaccharides, and the decolorization effect is not good, resulting in a low recovery rate of polysaccharides; hydrogen peroxide decolorization, severe oxidation reaction, poor condition control, resulting in polysaccharide degradation, structural damage and simple Polyphenols are oxidized and polymerized into colored substances; cetyltrimethylammonium bromide-n-hexanol-isooctane method decolorizes, which is easy to cause organic solvent residues, and the product has potential safety hazards

[0006] Salting out method, isoelectric point precipitation method to remove protein, the protein removal rate is low, and the effect is not good. If the salting out method is used to remove protein, the subsequent desalination process needs to be added

The sevag deproteinization method has mild conditions, but the single removal rate is low, and repeated deproteinization is required, the loss of tea polysaccharides is serious, the amount of organic solvent is large, and the toxic chloroform solvent is used. The whole process is time-consuming and expensive. The cost is high, the product has solvent residue, and the environment is seriously polluted; the deproteinization by trifluorotrichloroacetic acid method is acceptable, but the solvent is volatile, so the solvent loss is large and the environmental pollution is serious; the deproteinization method by trichloroacetic acid is violent and the conditions are not easy to control

[0007] The above-mentioned traditional decolorization and deproteinization methods all have deficiencies, such as polysaccharide degradation and structural damage, organic solvent residue, low efficiency, serious environmental pollution, etc., and decolorization and deproteinization are carried out in two steps, the process is cumbersome, and the loss of polysaccharides is serious.

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