How to extract plant polysaccharides?

Solvent extraction [2] is a common method to extract polysaccharides from plants. The first factor to be considered in solvent extraction is the choice of solvent, which should generally follow the principle of similar compatibility, that is, the effective components with strong polarity choose the solvent with strong polarity, and the components with weak polarity choose the solvent with weak polarity. Polysaccharide is a polar macromolecular compound, and polar solvents such as water and alcohol should be selected. Among all solvents, water is a typical strong polar solvent, which has penetrating power to plant tissues.

Strong, high extraction efficiency and safe production. Can be used for various plant polysaccharides, and has a wide range of uses. When water is used as solvent to extract polysaccharide, it can be extracted with hot water or cold water. The polysaccharides extracted by water are mostly neutral polysaccharides. Generally, plant polysaccharides are mostly extracted by hot water extraction, and the polysaccharide extract obtained by this method can directly or centrifugally remove insoluble substances; Or using the characteristic that polysaccharide is insoluble in high-concentration ethanol to precipitate and purify polysaccharide with high-concentration ethanol; However, due to the different ethanol concentrations required for the precipitation of polysaccharides with different properties or molecular weights, it can also be used for the classification and separation of different polysaccharide components in samples. Different polysaccharides in plants can also be separated in the coarse stage by extraction with mixed solvents according to the different properties of polysaccharides; Among them, ethanol precipitation is the most common [3]. Study on extraction method of crude polysaccharide from Porphyra yezoensis [4]

The control conditions of hot water extraction are: temperature 20~ 100℃, water and purple.

The ratio of liquid to solid is 50: 1, and the extraction time is 30 ~180 min.

The final yield is 2.05%. Zhou Zhiming [5] obtained hot water to extract Sargassum fusiforme.

The optimum extraction conditions of polysaccharide are as follows: extraction temperature is 65438 002℃, pH value is 3.0,

The extraction time was 3h, and the mass ratio of liquid to solid was 40: 1. Li Zhan [6] on three kinds of purple balls

The study on the extraction technology of seaweed shows that the best extraction technology of three kinds of Porphyridium is as follows

Each is different. The best extraction process of Porphyridium aeruginosa is ethanol concentration.

5%, the amount of ethanol is 3 times the volume, and the alcohol precipitation time is 65438±0.5h

The ratio of butanol is 4: 1, and the ratio of sample solution to Sevag reagent is 1:2.

The interval is 15 minutes. The best extraction process of Porphyridium is ethanol concentration.

75%, the amount of ethanol is twice the volume, the time of alcohol precipitation is 65438 0 h, chloroform and n-.

The ratio of butanol is 3: 1, and the ratio of sample solution to Sevag reagent is 1:2.

The interval is 45 minutes. The best extraction process of Porphyridium is ethanol concentration.

50%。 The dosage of ethanol is 1 volume, the time of alcohol precipitation is 0.5h, and chloroform is mixed with chloroform.

The ratio of n-butanol is 4: 1, and the ratio of sample solution to Sevag reagent is 2: 1.

The time is 45 minutes.

1.2 acid-base extraction method

Some polysaccharides are suitable for extraction with dilute acid or alkali solution to obtain more.

The extraction rate is high. However, the acid-base extraction method has its particularity, because polysaccharide is not

Same but different. Only when extracting certain plant polysaccharides, and

And even if there are advantages, the pH value should be strictly controlled in the operation [3]. because

Some polysaccharides may contain sugar under acidic or alkaline conditions.

Breakage of glycosidic bond. In addition, dilute acid and dilute alkali extracts should be quickly neutralized or accelerated.

Rapid dialysis, concentration and alcohol precipitation to obtain polysaccharide precipitate. Zhao Yu [7] and others.

The study on the extraction method of polysaccharide found that from the sulfate content and crude polysaccharide

In terms of yield, acid extraction method is better than water extraction method. The specific method is: 100g sea.

Add1000 ml 0.1mo1/l HCl solution for extraction. room temperature

Stir for 65438+/-0h, filter, repeat the operation for three times, and combine the filtrates; Concentrated filtrate under reduced pressure

Shrink to 1/5 of the total volume, and then add 95% ethanol until the ethanol concentration reaches.

30%, precipitation, centrifugation to remove alginic acid in precipitation, and continue to extract supernatant.

Add ethanol until the ethanol concentration reaches 7%. Standing at room temperature overnight for precipitation.

Completely, centrifugally, precipitating and drying to obtain Sargassum polysaccharide, which is calculated by many experiments.

The average yield is 3.35%.

Meng et al. [8] found that acid extraction is relative in the study of extraction of madder polysaccharide.

Compared with the water extraction method, the purity of madder polysaccharide extracted with dilute acid is high. special

The method is as follows: Radix Rubiae coarse powder 1000g 5% HCl soaking, centrifugation and collection.

Add ethanol to the supernatant, adjust the concentration to 7%, and let it stand at 2500rpm.

Centrifuge, collect brown precipitate, wash with 95% ethanol for 3 times, and wash with 45% ethanol.

Dissolve in hydrochloric acid. Decolorizing with 1% activated carbon, vacuum filtering, and passing the filtrate at 4℃

At night, discard a small amount of sediment at the bottom of the container. Put the solution in the dialysis bag and turn it upside down.

Dialysis for 3 days, freeze-drying to obtain about 65438 00 g white powdery polysaccharide.

Hayashi Katsuhiko[9] invented a method for extracting acid from green algae.

Sex polysaccharide method, which is not available by conventional hot water method. The specific process includes the following steps: making dried green algae powder into suspension and heating.

Soak in water to extract or directly extract water-containing green algae with hot water, and centrifuge.

Separating, taking viscous solid, adding alkaline water, and under the condition that the pH value is more than or equal to10.

Then stirring and extracting, wherein acid water is added into the alkaline water extraction solution under stirring.

Adjusting the pH value to 3.0-4.0, standing and settling, and centrifuging to obtain acidic polysaccharide.

1.3 biological enzyme extraction method

Enzymatic technology is one of the most widely used methods for extracting effective components in recent years.

A biotechnology, in the process of polysaccharide extraction, the amount of extraction can be reduced by using enzymes.

Conditions, decompose plant tissues under mild conditions, and accelerate polysaccharides.

Release or extract. In addition, the enzyme can also decompose starch and fruit in the extract.

Gum, protein and other products, commonly used enzymes are protease, cellulase, fruit.

Gelase, etc. Jiang Meng [10] studied the extraction effects of different enzymes on jujube residue.

The effect depends on polysaccharide yield, polysaccharide content and protein content.

The most suitable enzyme is complex enzyme 2 (trypsin extraction first, then)

Papain extraction), followed by papain, complex enzyme,

(Papain+trypsin), trypsin, pepsin

(pH=7.0), pepsin (pH=2.0). The action condition of compound enzyme 2 is warm.

Moreover, the yield and content of polysaccharide are high, and the content of protein is low, so it is a kind of polysaccharide.

An ideal enzyme extractant. Through further orthogonal experimental study, the optimum technological conditions were obtained.

Process: First, use 40 times of 3% trypsin, pH=7.0, 65℃.

After soaking 1.5h, add 2.5% papain, and add water at pH=7.0 and 50℃.

Soak in warm water for 65438±0h hours, add 40 times of water to the filter residue, and quickly raise the temperature to 80℃;

Then warm soak1.5h.

In addition, the extraction method of plant polysaccharide is ultrafiltration, which has strong ultrasonic wave.

Chemical method, microwave method and so on. The extraction methods and techniques of plant polysaccharides are constantly changing.

Improvement and innovation, but the same method and technology need to be planted in different plants.

Study on extraction method of polysaccharide. In the same way as selecting the separation method

, should be based on the characteristics of the target polysaccharide, physical and chemical properties, comprehensive ratio.

Compare and experiment, and choose the best method and extraction process.