Method for separating and purifying green organic acid and stabilizing gleditsia sinensis saponin

Abstract

The invention discloses a method for separating, purifying and stabilizing gleditsia sinensis saponin by using a green organic acid. The method comprises the following steps: firstly, extracting gleditsia sinensis shells by using an ethanol solvent to obtain crude gleditsia sinensis saponin; then, the coarse gleditsia sinensis saponin solution is pretreated with alum, insoluble impurities are preliminarily removed, and a clarified coarse gleditsia sinensis saponin solution is obtained; sequentially adding calcium oxide, carrying out segmented precipitation, and removing impurities (calcium polyphenol precipitate) to obtain gleditsia sinensis saponin calcium precipitate; and citric acid is used for segmentally releasing saponin, so that gleditsia sinensis saponin with relatively high purity is obtained. On the basis of precipitating the saponin by using the calcium oxide, the invention innovatively proposes that the saponin is precipitated by sections by using the calcium oxide and the citric acid is released by sections; the method is simple in process, green, safe, short in period and low in energy consumption. The invention widens the technology for separating and purifying the natural product saponin from the organic acid.

Description

Technical Field

[0001] The invention belongs to the field of natural saponin separation and purification, and specifically relates to a method for separating, purifying and stabilizing saponin using green organic acid. Background Art

[0002] Citric acid is an organic weak acid belonging to the fruit acid, which is colorless or white crystals. Citric acid is an intermediate in the tricarboxylic acid cycle and is mainly found in plant fruits such as lemons, citrus, pineapples, etc. In addition, citric acid can also be produced by microbial fermentation. In the food industry, citric acid is used as a variety of food additives, such as acidulants, buffers, preservatives, etc. In addition to food additives, it has the effect of softening the stratum corneum and good safety. In terms of daily chemical products, it can be used as lotions, creams, whitening products, etc. Citric acid is weakly acidic, has little corrosion to metals, and has good performance in metal cleaning; citric acid and its derivatives have a wide range of uses in the field of chemical cleaning due to their special physical and chemical properties. At the same time, citric acid forms stable complexes with a variety of metal ions and can be used as a release agent for calcium salt precipitation to release the desired substances. In addition, citric acid has good biosafety and biodegradability, and has good prospects in the green and safe purification of saponins.

[0003] Gleditsia sinensis is an excellent ecological and economic tree species. Gleditsia sinensis has a wide range of uses, and the whole body can be used, with high economic and medicinal value. The triterpenoid saponins and oligosaccharides contained in Gleditsia sinensis have anti-inflammatory, anti-ulcer, anti-lesion effects, as well as anti-cancer and AIDS immunity enhancement effects. Gleditsia sinensis shells are abundant in sources, extremely low in cost, and have great potential for utilization. However, at present, the utilization rate of the byproduct of Gleditsia sinensis shells after the use of Gleditsia sinensis seeds is extremely low, and the economic benefits of the Gleditsia sinensis industry have not yet been fully developed.

[0004] The development and utilization of green, eco-friendly and safe natural saponins are increasingly favored by consumers, but natural saponins have disadvantages such as high impurity content, dark color and unstable saponin structure.

[0005] At present, the traditional method for purifying saponins at home and abroad is mainly macroporous adsorption resin, but its cycle is long and it is impossible to purify saponins on a large scale. The present invention uses calcium oxide precipitation to remove impurities and realizes the component separation and purification of saponins. On the basis of using calcium oxide to precipitate saponins, the innovative citric acid segmented release is proposed to improve the purity of saponins while increasing the surface activity of saponins; the process is simple, green and safe, with a short cycle and low energy consumption. Summary of the invention

[0006] The purpose of the present invention is to design and provide a method for separating, purifying and stabilizing saponin from licorice, which overcomes the shortcomings of long saponin purification production process cycle and high energy consumption, and realizes efficient and green separation and purification of natural saponin.

[0007] The method involves a green organic acid separation, purification and stabilization method of nasturtium saponin, which is characterized by comprising the following process steps: 1) Extraction of crude saponin: crush the dried sapodilla shell through a 40-mesh sieve, use anhydrous ethanol as an extractant, stir and extract, filter, concentrate, and dry to obtain crude saponin; 2) Pretreatment: prepare a crude saponin aqueous solution, add alum, shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: taking the saponin solution obtained by pretreatment in step 2) above and subjecting it to calcium oxide precipitation, stirring at 30° C. for 30 min, centrifuging, filtering, washing, and collecting the precipitate to obtain a crude Gleditsia saponin calcium wet precipitate; 4) Segmented release of saponin: The saponin wet precipitate obtained by filtration in the above step 3) is subjected to segmented release by citric acid: 0.1 mol / L citric acid solution is added and then water is added, stirred, centrifuged, and filtered; the filtrate is added with solid citric acid, and heated at 70°C for 1 min (or heated at 60°C for 30 min) for release, centrifuged, filtered, concentrated, and dried to obtain purified saponin;

[0008] The method for separating, purifying and stabilizing saponin with green organic acid is characterized in that the anhydrous ethanol extraction in step 1) is divided into two stages, the solid-liquid ratio of the first stage is 1:10, the extraction temperature is 50°C, the extraction time is 2h, and then the extraction is performed at 70°C for 1h, and the second stage extraction temperature is 70°C, the extraction time is 1h, and the solid-liquid ratio is 1:6.

[0009] The method for separating, purifying and stabilizing saponin with green organic acid is characterized in that the concentration of the crude saponin aqueous solution in step 2) is 80 g / L, and the solution pH is 7. The mass ratio of alum to crude saponin is 1:100.

[0010] The method for separating, purifying and stabilizing nasturtium saponin with green organic acid is characterized in that the calcium oxide added in step 3) has a mass concentration of 10% relative to nasturtium saponin.

[0011] The method for separating, purifying and stabilizing nasturtium saponin with green organic acid is characterized in that in step 4), nasturtium saponin wet precipitation: citric acid solution = 1:3 (w / v); nasturtium saponin wet precipitation: deionized water = 1:2 (w / v). The added citric acid solid has a mass concentration of 2.11% relative to nasturtium saponin.

[0012] The method for separating, purifying and stabilizing saponin with green organic acid provided by the present invention has the following specific advantages:

[0013] 1. The present invention adopts alcohol extraction to extract crude saponin, adopts alum to pretreat saponin solution, adopts calcium oxide to precipitate saponin, and adopts citric acid to release saponin to extract saponin, and has the characteristics of high product yield, light product color, high purity of saponin, low saponin extraction cost, etc.

[0014] 2. The present invention preliminarily removes impurities in the crude saponin solution through alum pretreatment.

[0015] 3. The present invention removes polyphenols in nasturtium saponin by staged release when citric acid is released; and achieves stabilization of the structure of nasturtium saponin when citric acid is released in the second stage.

[0016] 4. The release agent citric acid used in the present invention is derived from natural plants or artificially synthesized, and the release agent is green and safe, with little pollution to the environment.

[0017] 5. The calcium oxide precipitation-citric acid release method for separating, purifying and stabilizing saponins has the advantages of easy operation, short production cycle, low energy consumption and cost, and green and safe production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The process flow chart of the embodiment combination. DETAILED DESCRIPTION

[0019] The invention is further described below in conjunction with the following examples. It should be understood that these examples are only used to illustrate the present invention, rather than to limit the scope of the present invention.

[0020] Example 1 1) Extraction of crude saponin: Grind the dried sapodilla shell through a 40-mesh sieve, extract with anhydrous ethanol as the extractant, solid-liquid ratio of 1:10, stir at 50°C for 2h, continue to extract at 70°C for 1h, filter; then extract with anhydrous ethanol as the extractant, solid-liquid ratio of 1:6, stir at 70°C for 1h, filter; concentrate the filtrate twice, dry and obtain crude saponin; 2) Pretreatment: prepare 80 g / L crude saponin aqueous solution, adjust pH to 7, add alum (mass ratio of alum to crude saponin = 1:100), shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: adding calcium oxide at a concentration of 7.75% relative to the mass concentration of crude Gleditsia saponin to the Gleditsia saponin filtrate, stirring at 30° C. for 30 min, centrifuging, filtering, washing, and collecting the precipitate to obtain crude Gleditsia saponin calcium precipitate; 4) Segmented release of saponin: Take the saponin precipitate in step 3) above and add 0.1 mol / L citric acid solution, saponin wet precipitate: citric acid solution = 1:3 (w / v), then add deionized water, saponin wet precipitate: deionized water = 1:2 (w / v), stir at room temperature for 20 minutes, centrifuge, filter, and remove saponin impurities. Add 2.11% citric acid solid relative to the mass of saponin calcium wet precipitate to the filtrate, and release by stirring at 60°C for 30 minutes, centrifuge, filter, concentrate and dry to obtain purified saponin. The purity of saponin was measured to be 82.94%.

[0021] Example 2 1) Extraction of crude saponin: Grind the dried sapodilla shell through a 40-mesh sieve, extract with anhydrous ethanol as the extractant, solid-liquid ratio of 1:10, stir at 50°C for 2h, continue to extract at 70°C for 1h, filter; then extract with anhydrous ethanol as the extractant, solid-liquid ratio of 1:6, stir at 70°C for 1h, filter; concentrate the filtrate twice, dry and obtain crude saponin; 2) Pretreatment: prepare 80 g / L crude saponin aqueous solution, adjust pH to 7, add alum (mass ratio of alum to crude saponin = 1:100), shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: adding calcium oxide at a concentration of 9% relative to the mass concentration of crude Gleditsia saponin to the Gleditsia saponin filtrate, stirring at 30° C. for 30 min, centrifuging, filtering, washing, and collecting the precipitate to obtain crude Gleditsia saponin calcium precipitate; 4) Segmented release of saponin: Take the saponin precipitate in step 3) above and add 0.1 mol / L citric acid solution, saponin wet precipitate: citric acid solution = 1:3 (w / v), then add deionized water, saponin wet precipitate: deionized water = 1:2 (w / v), stir at room temperature for 20 minutes, centrifuge, filter, and remove saponin impurities. Add 2.11% citric acid solid relative to the mass of saponin calcium wet precipitate to the filtrate, and release by stirring at 60°C for 30 minutes, centrifuge, filter, concentrate and dry to obtain purified saponin. The purity of saponin was measured to be 84.08%.

[0022] Example 3 1) Extraction of crude saponin: Grind the dried sapodilla shell through a 40-mesh sieve, use anhydrous ethanol as the extractant, solid-liquid ratio of 1:10, stir at 50°C for 2h, then continue to extract at 70°C for 1h, filter; then use anhydrous ethanol as the extractant, solid-liquid ratio of 1:6, stir at 70°C for 1h, filter; concentrate the filtrate twice, dry and obtain crude saponin; 2) Pretreatment: prepare 80 g / L crude saponin aqueous solution, adjust pH to 7, add alum (mass ratio of alum to crude saponin = 1:100), shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: adding calcium oxide at a concentration of 9% relative to the mass concentration of crude Gleditsia saponin to the Gleditsia saponin filtrate, stirring at 30° C. for 30 min, centrifuging, filtering, washing, and collecting the precipitate to obtain crude Gleditsia saponin calcium precipitate; 4) Segmented release of saponin: Take the saponin precipitate in step 3) above and add 0.1 mol / L citric acid solution, saponin wet precipitate: citric acid solution = 1:3 (w / v), then add deionized water, saponin wet precipitate: deionized water = 1:2 (w / v), stir at room temperature for 20 minutes, centrifuge, filter, and remove saponin impurities. Add 2.11% citric acid solid relative to the mass of saponin calcium wet precipitate to the filtrate, release at 70°C for 1 minute, centrifuge, filter, concentrate and dry to obtain purified saponin. The purity of saponin was measured to be 85.94%.

[0023] Example 4 1) Extraction of crude saponin: Grind the dried sapodilla shell through a 40-mesh sieve, use anhydrous ethanol as the extractant, solid-liquid ratio of 1:10, stir at 50°C for 2h, then continue to extract at 70°C for 1h, filter; then use anhydrous ethanol as the extractant, solid-liquid ratio of 1:6, stir at 70°C for 1h, filter; concentrate the filtrate twice, dry and obtain crude saponin; 2) Pretreatment: prepare 80 g / L crude saponin aqueous solution, adjust pH to 7, add alum (mass ratio of alum to crude saponin = 1:100), shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: adding calcium oxide at a concentration of 9% relative to the mass concentration of crude Gleditsia saponin to the Gleditsia saponin filtrate, stirring at 30° C. for 30 min, centrifuging, filtering, washing, and collecting the precipitate to obtain crude Gleditsia saponin calcium precipitate; 4) Segmented release of saponin: Take the saponin precipitate in step 3) above and add 0.1 mol / L citric acid solution, saponin wet precipitate: citric acid solution = 1:3 (w / v), then add deionized water, saponin wet precipitate: deionized water = 1:2 (w / v), stir at room temperature for 20 minutes, centrifuge, filter, and remove saponin impurities. Add 2.11% citric acid solid relative to the mass of saponin calcium wet precipitate to the filtrate, release at 70°C for 2 minutes, centrifuge, filter, concentrate and dry to obtain purified saponin. The purity of saponin was measured to be 83.21%.

[0024] Comparative Example 1 Deionized water was used as the extractant, the solid-liquid ratio was 1:10, the stirring temperature was 60℃, and the extract was extracted for 2h, filtered, and crude tea saponin water extract was obtained; 1.5% alum was added to the crude tea saponin water extract, oscillated for 1h at 70℃, allowed to stand for 3h, filtered while hot, and a clear saponin solution was obtained; calcium oxide was added at 2% of the volume of the saponin solution, stirred for 2h at room temperature, centrifuged, filtered, and saponin calcium precipitate was obtained; saponin calcium was dissolved at a solid-liquid ratio of 5:1, 50% acetic acid was added first according to chemical equilibrium, stirred evenly, and oscillated at 50℃ for 2h; 80% ammonium oxalate was added and reacted for 1h. The purity of saponin was measured to be 64.16%.

[0025] Comparative Example 2 Take a certain amount of camellia oleifera cake, crush and sieve, take the part with particle size ≤ 0.38mm, air dry at 105℃ for 5h, use petroleum ether as solvent, and Soxhlet extract at 90℃ water bath for 6-8h until the extract is colorless; air dry the defatted camellia oleifera cake at 60℃ for 1h; add 95% ethanol at a liquid-to-solid ratio of 9:1, heat and reflux at 70℃ for 4h, extract twice, and obtain a crude saponin solution; concentrate the solution, and add acetone 4 times the concentrated volume when it is concentrated to a thick paste. The purity of the saponin is measured to be 71.20%.

Claims

1. A method for separating, purifying and stabilizing saponins from licorice root using green organic acid, characterized in that The process steps include: 1) Extraction of crude saponin: crush the dried sapodilla shell through a 40-mesh sieve, use anhydrous ethanol as an extractant, stir and extract, filter, concentrate, and dry to obtain crude saponin; 2) Pretreatment: prepare a crude saponin aqueous solution, add alum, shake at 30°C for 1 hour, let stand for 3 hours, filter while hot to obtain a clear saponin solution; 3) Precipitation of Gleditsia saponin: taking the saponin solution obtained by pretreatment in step 2) above and subjecting it to calcium oxide precipitation, stirring at 30° C. for 30 min, centrifuging, filtering, and collecting the precipitate to obtain a crude Gleditsia saponin calcium wet precipitate; 4) Segmented release of saponin: The saponin wet precipitate obtained by filtration in the above step 3) is subjected to segmented release by citric acid: 0.1 mol / L citric acid solution is added and then water is added, stirred, centrifuged and filtered; the filtrate is added with citric acid solid, and heated at 60°C for release, centrifuged, filtered, concentrated and dried to obtain purified saponin.

2. The method according to claim 1, wherein the anhydrous ethanol extraction in step 1) is divided into two stages, the first stage is extracted at a temperature of 50°C, the extraction time is 2 hours, the extraction temperature is 70°C, the extraction time is 1 hour, the solid-liquid ratio is 1:10, and the second stage is extracted at a temperature of 70°C, the extraction time is 1 hour, and the solid-liquid ratio is 1:

6.

3. The method according to claim 1, wherein the concentration of the crude saponin aqueous solution in step 2) is 80 g / L, and the pH value of the solution is 7. The mass ratio of alum to crude saponin is 1:

100.

4. The method according to claim 1, wherein the calcium oxide added in step 3) has a mass concentration of 5% relative to the nasturtium saponin, and the calcium oxide in the second stage has a mass concentration of 10% relative to the nasturtium saponin.

5. The method according to claim 1, wherein in step 4), the ratio of the wet precipitate of saponin to the citric acid solution is 1:3 (w / v); the wet precipitate of saponin to deionized water is 1:2 (w / v).

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