CN113397206B - Preparation method of carboxymethylated momordica grosvenori polysaccharide and application of carboxymethylated momordica grosvenori polysaccharide in tobacco humectant - Google Patents

Abstract

The invention discloses a preparation method of carboxymethylated momordica grosvenori polysaccharide and application of carboxymethylated momordica grosvenori polysaccharide in a tobacco humectant, wherein the preparation method of carboxymethylated momordica grosvenori polysaccharide comprises the following steps: obtaining momordica grosvenori polysaccharide; carboxymethylation: carboxymethylation is carried out on the momordica grosvenori polysaccharide to obtain carboxymethylated momordica grosvenori crude polysaccharide; refining: the carboxymethylated momordica grosvenori crude polysaccharide is absorbed by macroporous resin, and is purified by gradient elution with 20-90% ethanol solution, so as to obtain the refined carboxymethylated momordica grosvenori polysaccharide. By optimizing the preparation method, the prepared refined carboxymethylated momordica grosvenori polysaccharide has extremely high purity, has good physical moisture retention and sensory quality evaluation effects on cigarettes, has good effects on rich cigarette fragrance, exquisite and soft smoke, proper concentration, clean aftertaste, sweet and comfortable taste and no irritation, and has good application prospect in cigarettes as a humectant for cigarettes.

Description

Preparation method of carboxymethylated Momordica grosvenori polysaccharide and its application in tobacco humectant

Technical Field

The invention relates to the field of tobacco, and in particular to a preparation method of carboxymethylated momordica grosvenori polysaccharide and application of the carboxymethylated momordica grosvenori polysaccharide in a tobacco humectant.

Background Art

At present, the domestic and foreign cigarette industries mainly use some traditional polyhydroxy humectants, such as propylene glycol, glycerin, etc. as humectants. The main purpose of such humectants is to stabilize the moisture content of tobacco during processing, avoid the breakage of tobacco during cigarette processing, and improve the processing strength of tobacco. However, the above-mentioned traditional humectants have a certain gap in stabilizing the moisture content of finished cigarette tobacco and improving the comfort of cigarette smoking under different climatic conditions.

Plant polysaccharides are large molecular polyhydroxy substances formed by the polymerization of a large number of monosaccharides. They can form relatively stable hydrogen bonds with water molecules, have good water retention properties, and have a good moisturizing effect in cigarette products. If plant polysaccharides are carboxymethylated, it can not only increase the solubility of plant polysaccharides in aqueous solutions, but also further improve the water retention capacity of plant polysaccharides, which can better exert the solubility and water retention effect of plant polysaccharides in solutions.

However, after the actual carboxymethylation of Momordica grosvenori polysaccharides, conventional purification methods cannot make the carboxymethylated Momordica grosvenori polysaccharides have a higher purity. Although this type of Momordica grosvenori carboxymethylated polysaccharides with lower purity can promote the water retention effect, it will still bring some adverse results to the smoking taste of cigarettes.

Summary of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the defect that the prior art cannot significantly purify the carboxymethylated polysaccharide, resulting in adverse effects on the smoking taste of cigarettes, thereby providing a method for preparing a carboxymethylated monk fruit polysaccharide with high purity that can solve the above-mentioned taste problem and its application in a tobacco humectant.

A method for preparing carboxymethylated Momordica grosvenori polysaccharide comprises the following steps:

Raw material acquisition: obtain Momordica grosvenori polysaccharide;

Carboxymethylation: Carboxymethylating the Momordica grosvenori polysaccharide to obtain carboxymethylated Momordica grosvenori crude polysaccharide;

Refining: The carboxymethylated Momordica grosvenori crude polysaccharide is adsorbed by macroporous resin D101 and purified by gradient elution with 20-90% ethanol solution. This is the most effective method to obtain carboxymethylated Momordica grosvenori polysaccharide with a refined purity of not less than 95%.

The macroporous resin model D101 is the most effective macroporous resin for obtaining refined high-purity carboxymethyl Momordica polysaccharide, and can increase the purity of Momordica polysaccharide to more than 95%.

When the concentration of the eluted ethanol solution is 40%-60%, the purity of the prepared Momordica grosvenori polysaccharide can reach more than 98%.

The carboxymethylation process is as follows: adding Momordica grosvenori polysaccharide, sodium hydroxide and a solvent into a reaction bottle, stirring to dissolve, then adding chloroacetic acid, stirring to react, cooling, adjusting the pH value to neutral, precipitating with alcohol, filtering and collecting the precipitate, dissolving the precipitate with water, precipitating with alcohol, dialyzing, and freeze-drying to obtain the product;

The mass ratio of the Momordica grosvenori polysaccharide, sodium hydroxide, solvent and chloroacetic acid is 10:18:150:20; and the solvent is composed of a carboxylating agent and water in a mass ratio of 2:1.

The reaction temperature of the stirring reaction is 55-75° C., and the reaction time is 4-5 hours.

The carboxylating agent is 1-butyl-3-methylimidazolyl chloride.

A refined carboxymethylated Momordica grosvenori polysaccharide is prepared by the above-mentioned preparation method.

Application of carboxymethylated Momordica grosvenori polysaccharide in tobacco humectant.

The added amount of the carboxymethylated Momordica grosvenori polysaccharide is 0.001-0.015% of the weight of the tobacco shreds. Preferably, the added amount of the carboxymethylated Momordica grosvenori polysaccharide is 0.001-0.005% of the weight of the tobacco shreds.

The technical solution of the present invention has the following advantages:

1. The preparation method of carboxymethylated Momordica polysaccharide provided by the present invention is that the reason for the taste problem lies in some by-products brought about in the carboxymethylation process. Therefore, in the present invention, the carboxymethylated Momordica polysaccharide is refined by using a macroporous resin to prepare a carboxymethylated Momordica polysaccharide with a higher purity in a very simple purification process. A carboxymethylated Momordica polysaccharide with a purity greater than 95% can be obtained by a simpler method. The carboxymethylated Momordica polysaccharide prepared by the method can achieve the effect of improving water retention and effectively improve the sensory performance of cigarettes.

2. The present invention further optimizes the process of carboxymethylation. The process of carboxymethylation in the present invention is as follows: adding Momordica grosvenori polysaccharide, sodium hydroxide and a solvent to a reaction bottle, stirring and dissolving, then adding chloroacetic acid, stirring and reacting, cooling, adjusting the pH value to neutral, precipitating with alcohol, filtering and collecting the precipitate, dissolving the precipitate in water, precipitating with alcohol, dialyzing, and freeze-drying; the mass ratio of the Momordica grosvenori polysaccharide, sodium hydroxide, solvent and chloroacetic acid is 10:18:150:20; the solvent is composed of a carboxylating agent and water in a mass ratio of 2:1; in the above process, the composition and ratio of the raw materials are mainly optimized. By optimizing the composition and ratio of the raw materials and combining the concentration of ethanol in the refining step, carboxymethylated Momordica grosvenori polysaccharide with higher yield and purity can be obtained.

3. The refined carboxymethylated Momordica grosvenori polysaccharide obtained by the present invention has a significant effect on the sensory quality of cigarette products, is an excellent tobacco humectant, and has great application value in the cigarette industry.

DETAILED DESCRIPTION

The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

The main reagents and instruments used in the experiment are:

Sodium hydroxide, acetic acid, ethanol 95%, phenol, sulfuric acid, sodium chloride (Kermiou Guangdong Reagent, analytical grade), 1-butyl-3-methylimidazolyl chloride (Lanzhou Institute of Chemical Physics, analytical grade), macroporous resin D101 (Suzhou Runmiao Environmental Protection Technology Co., Ltd.), and distilled water were used in the experiment.

AG204 analytical balance (sensitivity 0.0001g, METTLERTOLEDO, Switzerland), R-25 rotary evaporator (BUCHI, Switzerland); V-700 vacuum pump (BUCHI, Switzerland); low-temperature cooling circulation pump (BUCHI, Switzerland); SH23-2 constant temperature magnetic stirrer (Shanghai Meiyingpu Production Plant); ZK-82B electric vacuum drying oven (Shanghai Shenguang Instrument Co., Ltd.); CHRIST freeze dryer (BUCHI, Switzerland); macroporous resin D101 (Suzhou Runmiao Environmental Protection Technology Co., Ltd.).

In the present invention, the raw material Momordica grosvenori is a common commercially available product.

The Momordica polysaccharide in the following embodiment is prepared by the following method: 500 grams of crushed dried Momordica grosvenori is extracted with 1500 ml of petroleum ether (60-90° C.) for 2.5 hours to remove grease, and the residue is evaporated. The residue after evaporation is extracted twice with 2000 grams of boiling water each time, and the extracts obtained from the two extractions are combined, concentrated, centrifuged, and the supernatant is taken, and anhydrous ethanol 3 times the volume of the supernatant is added for alcohol precipitation, and the precipitate is collected by centrifugation again. After the precipitate is washed with ethanol twice in turn, it is dissolved with an appropriate amount of distilled water, and 0.1% of the weight of the precipitate is added with papain and placed in a 55° C. water bath for 3 hours for protein hydrolysis. The mother liquor after protein removal was decolorized by adding 10 g of activated carbon, heated in a 70°C water bath for 2 hours, and then cooled to room temperature, the activated carbon was removed by filtration, and the solution was concentrated under reduced pressure to 500 g, placed in a dialysis bag, and dialyzed with running water for 40 hours to remove small molecular impurities. After the dialysis, anhydrous ethanol 3 times the volume of the polysaccharide solution after dialysis was added again for alcohol precipitation, and the solution was allowed to stand for 10 hours. After centrifugation, the precipitate was dried at 75°C to obtain 22.3 g of crude polysaccharide, and the yield of crude polysaccharide was 4.46%. 3.0 g of crude polysaccharide was dissolved in distilled water, separated and purified by macroporous resin D101 column chromatography, eluted with 50% ethanol solution, and the eluate was collected. The eluate was colorimetrically detected by sulfuric acid phenol method to detect the elution of polysaccharide in the eluate, and the eluate was collected, concentrated, and freeze-dried to obtain 876 mg of refined Momordica grosvenori polysaccharide, with a yield of 29.2%. After testing, the purity of Momordica grosvenori polysaccharide was 98.1%.

If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

Example 1

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 55°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 20% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 25.1%. After testing, the purity was 96.10%.

Example 2

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 70°C for 5 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 30% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 26.7%. After testing, the purity was 97.0%.

Example 3

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 70°C for 5 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 40% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 28.1%. After testing, the purity was 98.1%.

Example 4

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 65°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 50% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 29.2%. After testing, the purity was 98.1%.

Example 5

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 65°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 60% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 29.1%. After testing, the purity was 98.1%.

Example 6

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 65°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 70% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 27.0%. After testing, the purity was 96.10%.

Example 7

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 65°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 80% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 25.1%. After testing, the purity was 95.10%.

Example 8

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 65°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

The crude carboxymethylated Momordica grosvenori polysaccharide sample was dissolved in distilled water, added to a pretreated macroporous resin D101 column, eluted with 90% ethanol solution, detected by phenol-sulfuric acid method, and the samples of each receiving tube containing polysaccharide were collected (10 ml were collected in each receiving tube), freeze-dried, and the refined carboxymethylated Momordica grosvenori polysaccharide was obtained with a yield of 24.5%. After testing, the purity was 95.0%.

Comparative Example 1

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 18 grams of sodium hydroxide and 150 milliliters of solvent (the mass ratio of carboxylating agent to water is 2:1, and the carboxylating agent is 1-butyl-3-methylimidazolyl chloride) into a round-bottom three-necked bottle, stirring at room temperature until the solution is clear, adding 10 grams of refined Momordica grosvenori polysaccharide, stirring for 30 minutes until it is completely dissolved, then slowly adding 20 grams of chloroacetic acid, continuing to stir and react at 55°C for 4 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate.

The precipitate was dissolved with an appropriate amount of water, precipitated with 3 times the volume of 95% ethanol, and centrifuged at high speed for 20 minutes. The precipitate was collected again and dialyzed with running water using a dialysis bag. First, it was dialyzed with tap water, then with distilled water, and finally freeze-dried to obtain milky white cotton-like carboxymethylated Momordica grosvenori crude polysaccharide.

After testing, the yield of the carboxymethylated Momordica grosvenori crude polysaccharide was 75.2% and the purity was 81.0%.

Comparative Example 2

A preparation method of carboxymethylated Momordica grosvenori polysaccharide comprises the following steps: adding 6 grams of Momordica grosvenori polysaccharide and 120 milliliters of isopropanol into a round-bottom three-necked flask, stirring for 20 minutes at 400 r/min, adding 420 milliliters of a sodium hydroxide solution with a mass concentration of 20%, reacting at room temperature for 2 hours, adding 480 milliliters of a chloroacetic acid isopropanol solution with a mass fraction of 16%, heating to 60° C. for heat preservation and reaction for 5 hours, cooling to room temperature, adjusting the pH value to 7 with dilute acetic acid, precipitating with alcohol, filtering, and collecting the precipitate; washing the precipitate with 95% ethanol for 3 times, collecting the precipitate, and freeze-drying to obtain the crude carboxymethylated Momordica grosvenori polysaccharide.

After testing, the yield of the carboxymethylated Momordica grosvenori crude polysaccharide was 50.3% and the purity was 72.1%.

Test Example 1

In order to investigate the physical moisture retention performance (water retention) of carboxymethylated Momordica polysaccharide on cigarettes, the carboxymethylated Momordica polysaccharide prepared in Examples 1-8 and Comparative Examples 1-2 was used as a carrier, and the physical moisture retention performance comparison test was conducted with Momordica polysaccharide. The specific test process is as follows:

The carboxymethylated Momordica polysaccharide and Momordica polysaccharide of Examples 1-8 were simultaneously prepared into an aqueous solution with a mass fraction of 0.05%. According to the purity of Comparative Examples 1-2, it was prepared into an aqueous solution with the same content of carboxymethylated Momordica polysaccharide as that in Example 5, and the concentration of the aqueous solution = (purity of Example 5*0.05%)/purity of Comparative Example.

First, place the blank cigarette tobacco in an environment with a temperature of 22±1°C and a relative humidity of 60±2% for 48 hours. Obtain several equal portions of tobacco, each portion of 200 grams, and evenly apply 4 grams of aqueous solutions of the compounds in the above-mentioned embodiments and comparative examples to the tobacco, and the control blank sample is a tobacco uniformly applied with 4 grams of water. Then, the tobacco of each group is placed in an environment with a temperature of 22±1°C and a relative humidity of 40±2% to observe its dehumidification process, and analyze the change of the instant moisture content (%) to examine its physical moisturizing effect.

The test results of the instantaneous moisture content (%) at the corresponding time in each embodiment and comparative example are shown in Table 1.

Table 1

The test results show that the physical wetting properties of the tobacco preservative carboxymethylated Momordica grosvenori polysaccharide after adsorption on a macroporous resin D101 column and elution and purification with a 20-90% ethanol solution are good. Among them, the physical wetting properties of the tobacco preservative carboxymethylated Momordica grosvenori polysaccharide after adsorption on a macroporous resin D101 and elution and purification with a 40-60% ethanol solution are the best, followed by other gradient elutions of different concentrations of ethanol solutions.

Test Example 2

In order to investigate the sensory moisturizing performance of carboxymethylated Momordica grosvenori polysaccharide on cigarettes, the present invention adopts the following method for testing:

The refined carboxymethylated Momordica polysaccharide of Examples 1-8 was prepared into a solution with a mass fraction of 0.1% using a 20% ethanol (volume ratio) aqueous solution as a solvent; at the same time, according to the purity of Comparative Examples 1 and 2, after conversion, a carboxymethylated Momordica polysaccharide solution having the same content of carboxymethylated Momordica polysaccharide as that in Example 5 per unit volume was prepared.

Then, 5.000 g of the solution was sprayed onto 100 g of unflavored blank cigarette shreds of Zhenlong (Xiangyun) to make cigarettes. 100 cigarettes of the same weight were selected for each sample. The 100 cigarette samples corresponding to each embodiment and comparative example and 100 blank control cigarettes of Zhenlong (Xiangyun) were equilibrated in a constant temperature and humidity chamber at a temperature of 22 ± 1°C and a humidity of 60 ± 2 (%) for 48 hours.

20 smoking evaluation experts were selected to evaluate the cigarettes of different embodiments and comparative examples. The selection range of smoking evaluation experts was the expert pool members of the Cigarette Quality Evaluation Technical Committee of Guangxi Zhuang Autonomous Region Tobacco Monopoly Bureau. The evaluation was conducted according to the technical requirements of cigarette sensory quality of GB5606.4-2005 to score the gloss, aroma, coordination, miscellaneous smell, irritation and aftertaste. The average value was calculated after scoring. The scoring results are shown in Table 2.

Table 2

The above results show that the main effect of carboxymethylated monk fruit polysaccharide as a tobacco humectant on the sensory quality of cigarettes is to enrich the tobacco aroma, reduce irritation and mask impurities, making the smoke delicate and soft, the aftertaste clean, and the taste sweet and comfortable.

Test Example 3

The present invention also evaluates the sensory performance of carboxymethylated Momordica polysaccharide, a humectant for tobacco, at different concentrations. Specifically, a 20% ethanol (volume ratio) aqueous solution is used as a solvent, and the carboxymethylated Momordica polysaccharide, a humectant for tobacco, obtained by refining in Example 5, is prepared into a solution with a mass fraction of 0.1%. 0.100 g, 0.500 g, 1.000 g, 5.000 g, 10.000 g, 15.000 g and 20.000 g of the above-mentioned solution containing carboxymethylated Momordica polysaccharide are respectively taken and sprayed into seven portions of 100 g of blank cigarette shreds of Zhenlong (Xiangyun) without flavoring to make cigarettes. For each sample, 100 cigarettes of the same weight and a blank control sample cigarette Zhenlong (Xiangyun) are selected and balanced in a constant temperature and humidity box at a temperature of 22 ± 1 ° C and a humidity of 60 ± 2 (%) for 48 hours. The seven samples are evaluated by smoking experts. The evaluation results are shown in Table 3.

Table 3

It can be seen from the results of the smoking evaluation in Table 3 that when the amount of carboxymethylated Momordica polysaccharide used as a tobacco humectant is small, its effect on the sensory quality of cigarettes is not significant. When its amount reaches 0.001%, the tobacco aroma is rich and slightly mixed, the smoke is delicate and soft, the concentration is reduced, the aftertaste is clean, the taste is sweet and comfortable, non-irritating, and the tobacco aroma is reduced. When the amount of carboxymethylated Momordica polysaccharide used as a tobacco humectant is 0.001% to 0.005%, the sensory quality evaluation of cigarettes is the best. Therefore, when the tobacco humectant carboxymethylated Momordica polysaccharide is added to cigarettes, the best effect is achieved, that is, the most suitable amount is 0.001% to 0.005%.

Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims (6)

1. A method for preparing carboxymethylated Momordica grosvenori polysaccharide as a tobacco humectant, characterized in that it comprises the following steps: Raw material acquisition: obtain Momordica grosvenori polysaccharide; Carboxymethylation: Carboxymethylating the Momordica grosvenori polysaccharide to obtain carboxymethylated Momordica grosvenori crude polysaccharide; Refining: The carboxymethylated Momordica grosvenori crude polysaccharide is adsorbed by macroporous resin D101, and purified by elution with 40-60% ethanol solution to obtain refined carboxymethylated Momordica grosvenori polysaccharide with a purity of not less than 95%; The carboxymethylation process is as follows: adding Momordica grosvenori polysaccharide, sodium hydroxide and a solvent into a reaction bottle, stirring to dissolve, then adding chloroacetic acid, stirring to react, cooling, adjusting the pH value to neutral, precipitating with alcohol, filtering and collecting the precipitate, dissolving the precipitate with water, precipitating with alcohol, dialyzing, and freeze-drying to obtain the product; The mass ratio of the Momordica grosvenori polysaccharide, sodium hydroxide, solvent and chloroacetic acid is 10:18:150:20; the solvent is composed of a carboxylating agent and water in a mass ratio of 2:1; The reaction temperature of the stirring reaction is 55 to 75°C, and the reaction time is 4 to 5 hours; The carboxylating agent is 1-butyl-3-methylimidazolyl chloride. 2. The preparation method according to claim 1, characterized in that the purity of the Momordica grosvenori polysaccharide is above 98%. 3. A refined carboxymethylated Momordica grosvenori polysaccharide, characterized in that it is prepared by the preparation method described in any one of claims 1 to 2. 4. Use of the carboxymethylated Momordica grosvenori polysaccharide according to claim 3 in a tobacco humectant. 5. The use according to claim 4, characterized in that the added amount of the carboxymethylated Momordica grosvenori polysaccharide is 0.001-0.015% of the weight of the tobacco. 6. The use according to claim 5, characterized in that the added amount of the carboxymethylated Momordica grosvenori polysaccharide is 0.001% to 0.005% of the weight of the tobacco.