Saponin hydrolysis process

Abstract

The present application relates to saponin hydrolysis technical field, specifically to saponin hydrolysis process.The saponin hydrolysis process includes the following steps: 1) adding water and acid in saponin to carry out hydrolysis to obtain sapogenin and sugar, the amount of water added is 15-25% of the mass of saponin;2) after hydrolysis, solvent is added to extract sapogenin, after extraction, the solvent containing sapogenin and moist solid residue are obtained;3) the moist solid residue is heated to recover residual solvent, and the remaining mixture is used as fertilizer or feed;4) the solvent containing sapogenin obtained in step 2) is concentrated and crystallized, the solid is collected by centrifugation, and the sapogenin is obtained by drying, and the recovered solvent is reused.The water phase is not recycled, the amount of water is reduced, the extraction effect of solvent on sapogenin can be greatly improved, and the moisture of hydrolyzate is further reduced by drying, so that the yield of sapogenin is further improved.

Description

Technical Field

[0001] This invention relates to the field of saponin hydrolysis technology, specifically to saponin hydrolysis processes. Background Technology

[0002] In existing technologies, saponin hydrolysis processes generally employ an aqueous phase recycling model. Patent CN111943991A discloses an extraction process for water-soluble saponins, with the following steps: adding acid and petroleum ether solvent to the saponin extract obtained by alcohol extraction for hydrolysis and saponin extraction; separating the materials to obtain solids, petroleum ether solvent, and acid solution containing water-soluble saponins, with the acid solution containing water-soluble saponins being directly returned to step 1) for reuse; the initial design intention is to reduce production costs by reusing the acid-containing aqueous phase and to attempt to enrich the saponins that are not fully extracted from the aqueous phase.

[0003] However, those skilled in the art have found in actual production that saponins in the circulating aqueous phase are destroyed when they participate in the hydrolysis process again. Even if they are continuously recycled and the hydrolysis steps are repeated, they cannot achieve the effect of saponin enrichment. The high water content of the aqueous phase significantly reduces the extraction rate of saponins by organic solvents, resulting in a decrease in saponin yield.

[0004] Meanwhile, in existing technologies, the forced neutralization of the moist solid residue generated after solid-liquid separation following saponin hydrolysis not only increases production costs but also limits the high-value utilization of by-products, as their acidity also limits applicable technical fields.

[0005] Therefore, there is an urgent need to develop a hydrolysis process that can simultaneously solve the three major problems of low saponin yield, low resource utilization, and limited product application. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a saponin hydrolysis process that solves the problems of low saponin yield, low resource utilization, and limited product applications.

[0007] The saponin hydrolysis process of the present invention includes the following steps:

[0008] 1) Add water and acid to saponins to hydrolyze them to obtain saponins and sugars. The amount of water added is 15-25% of the mass of the saponins.

[0009] 2) After hydrolysis, add solvent to extract saponin. After extraction, a solvent containing saponin and a moist solid residue are obtained.

[0010] 3) The residual solvent is recovered by heating the moist solid residue, and the remaining mixture is used as fertilizer or feed;

[0011] 4) Concentrate and crystallize the saponin-containing solvent obtained in step 2), collect the solid by centrifugation, dry it to obtain saponin, and recover the solvent for reuse.

[0012] The acid mentioned in step 1) is sulfuric acid or hydrochloric acid.

[0013] Step 1) The mass ratio of acid to water is (8-12):(88-100).

[0014] Step 2) The amount of solvent added is 0.8-1 times the mass of the saponin.

[0015] Step 2) The hydrolyzed mixture is dried until the moisture content is less than 6%. Theoretically, drying before solvent extraction can reduce the moisture content and achieve good results. Even if too much water is added during hydrolysis in step (1), it can be remedied by drying in this step. However, in actual production, it is unnecessary to add too much water in step (1), which would only cause unnecessary workload for subsequent drying and water treatment processes.

[0016] A lower water content allows for more complete extraction of saponins by the subsequent solvent. Water evaporates upon heating, which does not cause saponin loss but instead increases the saponin concentration. Minimal water content weakens the protective effect of water on saponins, making it easier for the solvent to extract them.

[0017] The hydrolysis temperature in step 1) is 105-115℃, and the hydrolysis time is 1.5-2.5h.

[0018] The solvent in step 2) is one or more of n-hexane, petroleum ether, and No. 120 gasoline.

[0019] The solvent described in step 4) is first purified and then concentrated and crystallized.

[0020] The purification process involves adding activated carbon for adsorption.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The aqueous phase of the present invention is not recycled, which reduces the amount of water added and can greatly improve the extraction effect of the solvent on saponin, thereby increasing the saponin yield. Even if the aqueous phase is recycled to enrich the saponin, the saponin content will not increase as desired, which is time-consuming and laborious.

[0023] (2) The wet solid residue after the solvent is recovered in this invention is a mixture of sugars, water and acid. Without adding alkali to neutralize it, its application range can be wider. It is suitable for acidic fields, such as fertilizers and soil conditioners. Alternatively, it can be neutralized with alkali later to obtain a mixture of sugars, water and salt, which is suitable for neutral fields, such as feed.

[0024] (3) The present invention reduces the moisture content of the hydrolysate by drying, which is more conducive to improving the extraction effect of the solvent on saponin, thereby increasing the saponin yield. Attached Figure Description

[0025] In the attached diagram:

[0026] Figure 1 This is a three-dimensional structural diagram of the leaching device for solid-liquid separation and discharge according to an embodiment of the present invention;

[0027] Figure 2 This is a top view of the leaching device for solid-liquid separation and discharge according to an embodiment of the present invention;

[0028] Figure 3 This is a three-dimensional structural diagram of the oil collecting hopper of the leaching device for solid-liquid separation and discharge according to an embodiment of the present invention;

[0029] Figure 4 This is a bottom view of the dummy bottom of the leaching device for solid-liquid separation and discharge according to an embodiment of the present invention;

[0030] In the picture:

[0031] 1. Leacher; 2. Leaching chamber; 3. Separation plate; 4. Turbulence chamber; 5. Overflow chamber; 6. Discharge chamber; 7. Feed pipe; 8. Replenishment pipe; 9. False bottom; 10. Rotating shaft; 11. Spraying device; 12. Discharge pipe; 13. Pump; 14. Inlet pipe; 15. Solid transport device; 16. Oil hopper; 17. Oil collection chamber; 18. Dividing plate; 19. Filter screen; 20. Solid discharge transport device; 21. Solvent discharge pipe; 22. Feed chamber; 23. Replenishment chamber. Detailed Implementation

[0032] The present invention will be further described below with reference to the embodiments.

[0033] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0034] The saponin is diosgenin, a yam extract from Xi'an Muguo Biotechnology Co., Ltd.; purity > 98%.

[0035] The leaching apparatus for solid-liquid separation and discharge used in the following embodiments and comparative examples, such as Figure 1-4As shown, the solid-liquid separation and discharge leaching device includes a leachator 1. A rotating shaft 10 is located at the center of the leachator 1, and the rotating shaft 10 is connected to a drive device. A separation plate 3 connecting the rotating shaft 10 and the inner wall of the leachator 1 divides the device into several leaching compartments 2. An oil collecting hopper 16 is located at the bottom of the leachator 1, with a diameter larger than that of the leachator 1 above. Several dividing plates 18 are arranged along the outer diameter from the center of the oil collecting hopper 16. The dividing plates 18 sequentially divide the device along the rotation direction of the rotating shaft 10 into a feed compartment 22, two oil collecting compartments 17, a replenishment compartment 23, a turbulence compartment 4, an overflow compartment 5, and a discharge compartment 6. The height of the dividing plates 18 is along the rotation direction of the rotating shaft. The rotation direction increases sequentially. The bottom of the leaching tank 2 is provided with a false bottom 9, which does not rotate with the leaching tank 1. The bottom of the leaching tank 2 corresponding to the discharge tank 6 is not provided with a false bottom 9. The bottom of the churning tank 4 is connected to one end of the solid transport device 15. The other end of the solid transport device 15 is located above the leaching tank 2 corresponding to the overflow tank 5. The false bottom 9 is provided with a spraying mechanism corresponding to each leaching tank 2. The leaching tank 2 above the overflow tank 5 is not provided with a spraying mechanism. The leaching tank 2 above the feed tank 22 is provided with a feed pipe 7. The leaching tank 2 above the replenishment tank 23 is provided with a replenishment pipe 8.

[0036] Understandably, the solid transport device 15 is a scraper conveyor, with a discharge port located directly above the leaching tank 2.

[0037] Understandably, the spraying mechanism includes an inlet pipe 14 connected to the oil collection hopper 16, an inlet pipe 14 connected to a pump 13, a pump 13 connected to an outlet pipe 12, an outlet pipe 12 connected to a spraying device 11, which is fixedly connected to the bottom surface of the false bottom 9. The spraying device 11 has several spraying holes facing the leaching grid 2.

[0038] The spray mechanism at the bottom of each leaching cell 2, corresponding to the position of the false bottom 9, extracts the solvent overflowing into the oil collection hopper 16 below and injects it back into the leaching cell 2 from the bottom, causing the internal solids to surge and achieve full extraction. The height of the solid surging is controlled by the pump 13 to ensure it does not exceed the upper edge of the leaching cell 2, preventing solid powder from overflowing into the lower oil collection hopper 16 and causing solid loss. By controlling the pump 13 of the spray mechanism corresponding to the surging cell 4, the solids in the leaching cell 2 above the surging cell 4 surge violently, overflowing from the upper edge of the leaching cell 2 along with the solvent into the surging cell 4 below, increasing the solids in the surging cell 4. The solids in the surging cell 4 are then transported to the leaching cell 2 above the overflow cell by the solid transport device 15. The transport speed of the solid transport device 15 is controlled to maintain the solid height in the leaching cell 2 at the upper edge position of the leaching cell 2, allowing the solvent to overflow.

[0039] Understandably, the height of the dividing plate 18 increases sequentially along the rotation direction of the rotation axis 10.

[0040] The rotation direction of the leaching chamber 2 in the leaching unit 1 is opposite to the direction of solvent overflow in the oil collection hopper 16. This enables the use of saturated solvent to leach the solid that has just been fed in, and the use of unsaturated solvent to leach the solid powder that is about to complete the leaching process. This countercurrent leaching method is highly efficient and effective.

[0041] Understandably, a filter screen 19 is provided on the top of the dividing plate 18 between the churning grid 4 and the oil collecting grid 17.

[0042] To prevent solids in the overflowing compartment 4 from overflowing into the adjacent oil collection compartment 17, a filter screen is installed above the compartment plate 18. This prevents solid powder from continuing to overflow downwards and eventually being discharged with the solvent, thus keeping the overflowing solvent clean.

[0043] Understandably, the discharge compartment 6 is connected to the solid discharge conveying device 20, and the side wall of the feed compartment 22 is connected to the solvent discharge pipe 21.

[0044] The solid transport device 15 and the solid discharge transport device 20 are scraper conveyors.

[0045] Working principle: The feed pipe 7 is opened to uniformly pump the hydrolyzed mixture to be extracted into the corresponding leaching cell 2 above the feed cell 22. The rotating shaft 10 drives the extractor 1 to rotate via the drive device. The leaching cell 2 of the extractor 1 rotates and passes sequentially from the feed cell 22 through several oil collection cells 17, replenishment cells 23, turbulence cells 4, overflow cells 5, and discharge cells 6. The replenishment pipe 8 is opened to uniformly add solvent into each leaching cell 2. As the solvent is continuously added, the leaching cell 2 is filled, and the solvent flows downwards from the top edge of the leaching cell 2. The solvent overflows into the oil collection grid 17 of the oil collection hopper 16. The solvent in the oil collection grid 17 is then transported to the spraying device 11 through the inlet pipe 14, pump 13, and outlet pipe 12. The solvent is replenished from the bottom of the leaching grid 2 through the spray holes on the spraying device 11, thereby causing the hydrolyzed mixture in the leaching grid 2 to surge, achieving full contact and extraction between the hydrolyzed mixture and the solvent. The solvent in the oil collection grid 17 overflows downward with the progressively lowering dividing plates 18, and finally flows into the feed grid 22, where it is transported at a fixed rate through the solvent discharge pipe 21. The solvent is recovered by the solvent recovery device. The solvent saturation in the feed cell 22 is the highest, so the newly added hydrolyzed mixture can be extracted with the solvent with the highest saturation, thus achieving countercurrent extraction of the solvent. The spray mechanism at the position of the turbulence cell 4 corresponding to the false bottom 9 adds solvent upwards at a fast rate, and the internal turbulence is more intense, so that solids and liquids fall together from the upper edge of the leaching cell 2 into the lower turbulence cell 4, increasing the amount of solids in the turbulence cell 4. The solid powder overflowing from the turbulence cell 4 is continuously transported upwards to the top of the leaching cell 2 above the overflow cell 5 by the solid transport device 15 at a certain transport speed, and falls through the discharge port. The transport speed of the solid transport device 15 is controlled so that the height of the solid powder in the leaching cell 2 corresponding to the overflow cell 5 is maintained at the upper edge of the leaching cell 2, causing the solvent to overflow. After the solvent overflows, the leaching cell 2 continues to rotate to the top of the discharge cell. Because the false bottom 9 is missing between the discharge cell and the leaching cell 2, the solids fall directly into the discharge cell and are transported by the solid discharge transport device 20 at the bottom to the next stage for solid-liquid separation.

[0046] Example 1

[0047] The saponin hydrolysis process includes the following steps:

[0048] 1) Add 200 kg of water and 20 kg of sulfuric acid to 1 t of saponins and hydrolyze them in a sealed container to obtain saponins and sugars. The hydrolysis temperature is 110℃ and the hydrolysis time is 2 h.

[0049] 2) After hydrolysis, the hydrolyzed mixture is dried to control the moisture content to be below 6%. 900 kg of n-hexane is added to extract the saponin. The saponin is extracted using a solid-liquid separation leaching device for 1.5 hours. After extraction, n-hexane containing saponin and moist solid residue are obtained.

[0050] 3) The wet solid residue is heated to recover the residual n-hexane, and the remaining mixture is used as fertilizer or feed;

[0051] 4) Add activated carbon to the n-hexane containing saponin obtained in step 2) for adsorption and then filter. Then concentrate and crystallize the adsorbed n-hexane, collect the solid by centrifugation, and dry it to obtain 452.2 kg of saponin with a melting point of 197℃. The n-hexane is recovered and reused.

[0052] Example 2

[0053] The saponin hydrolysis process includes the following steps:

[0054] 1) Add 150kg of water and 12kg of sulfuric acid to 1t of saponins and hydrolyze them in a sealed container to obtain saponins and sugars. The hydrolysis temperature is 115℃ and the hydrolysis time is 2.5h.

[0055] 2) After hydrolysis, the hydrolyzed mixture is dried to control the moisture content to be below 6%. 800 kg of n-hexane is added to extract the saponin. The saponin is extracted using a solid-liquid separation leaching device for 1.5 hours. After extraction, n-hexane containing saponin and moist solid residue are obtained.

[0056] 3) The wet solid residue is heated to recover the residual n-hexane, and the remaining mixture is used as fertilizer or feed;

[0057] 4) Add activated carbon to the n-hexane containing saponin obtained in step 2) for adsorption and then filter. Then concentrate and crystallize the adsorbed n-hexane, collect the solid by centrifugation, and dry it to obtain 450.9 kg of saponin with a melting point of 197℃. Recover the n-hexane for reuse.

[0058] Example 3

[0059] The saponin hydrolysis process includes the following steps:

[0060] 1) Add 250kg of water and 30kg of hydrochloric acid to 1t of saponins and hydrolyze them in a sealed container to obtain saponins and sugars. The hydrolysis temperature is 105℃ and the hydrolysis time is 1.5h.

[0061] 2) After hydrolysis, the hydrolyzed mixture is dried to control the moisture content to be below 6%. 1000 kg of n-hexane is added to extract the saponin. The saponin is extracted using a solid-liquid separation leaching device for 1.5 hours. After extraction, n-hexane containing saponin and moist solid residue are obtained.

[0062] 3) The wet solid residue is heated to recover the residual n-hexane, and the remaining mixture is used as fertilizer or feed;

[0063] 4) Add activated carbon to the n-hexane containing saponin obtained in step 2) for adsorption and then filter. Then concentrate and crystallize the adsorbed n-hexane, collect the solid by centrifugation, and dry it to obtain 455.8 kg of saponin with a melting point of 198℃. The n-hexane is recovered and reused.

[0064] Example 4

[0065] The saponin hydrolysis process includes the following steps:

[0066] 1) Add 200 kg of water and 20 kg of sulfuric acid to 1 t of saponins and hydrolyze them in a sealed container to obtain saponins and sugars. The hydrolysis temperature is 110℃ and the hydrolysis time is 2 h.

[0067] 2) After hydrolysis, add 900 kg of n-hexane to extract saponin. Use a solid-liquid separation leaching device to extract saponin for 1.5 hours. After extraction, n-hexane containing saponin and moist solid residue are obtained.

[0068] 3) The wet solid residue is heated to recover the residual n-hexane, and the remaining mixture is used as fertilizer or feed;

[0069] 4) Add activated carbon to the n-hexane containing saponin obtained in step 2) for adsorption and then filter. Then concentrate and crystallize the adsorbed n-hexane, collect the solid by centrifugation, and dry it to obtain 430.2 kg of saponin with a melting point of 196℃. The n-hexane is recovered and reused.

[0070] As can be seen from this non-preferred embodiment, if the water content is controlled to be below 6% and the solvent is added directly for extraction without drying after hydrolysis, the extraction effect of the solvent on saponins will be reduced, resulting in a lower yield.

[0071] Comparative Example 1

[0072] The saponin hydrolysis process includes the following steps:

[0073] 1) Add 500 kg of water and 50 kg of sulfuric acid to 1 t of saponins and hydrolyze them in a sealed container to obtain saponins and sugars. The hydrolysis temperature is 110℃ and the hydrolysis time is 2 h.

[0074] 2) After hydrolysis, add 900 kg of n-hexane to extract saponin. Use a solid-liquid separation leaching device to extract saponin for 1.5 h to obtain n-hexane containing saponin, moist solid residue, and acidic water containing saponin and sugar.

[0075] 3) Add acidic water containing saponins and sugar to step 1) to replace part of the water and repeat the hydrolysis process. After repeating the cycle 3 times, the saponins enriched in the water are destroyed by repeated participation in the hydrolysis process, and the sugar in the recycled water continues to accumulate and becomes viscous, making the recycled water unusable.

[0076] 4) After three cycles, add activated carbon to the n-hexane containing saponin obtained in step 2) for adsorption and then filter. Then concentrate and crystallize the adsorbed n-hexane, collect the solid by centrifugation, and dry it to obtain 1073.4 kg of saponin with a melting point of 195℃. The n-hexane is recovered and reused.

[0077] The comparative example yielded a total of 1073.4 kg of saponin in three production runs, with an average yield of 357.8 kg of saponin per run. The yield was much lower than that of the embodiment of the present invention. This is because the presence of excessive water reduced the extraction effect of the solvent on saponin. At the same time, the presence of saponin in the water caused it to be destroyed during repeated hydrolysis, preventing the enrichment process. In addition, the increased sugar content in the water made it more viscous, which affected the hydrolysis process and the extraction of the solvent, resulting in an even lower yield.

[0078] The saponins obtained in the examples and comparative examples were tested:

[0079] Alcohol-insoluble matter test: Prepare a 1 wt.% ethanol solution of the above saponin product and examine it at room temperature. No turbidity should be observed.

[0080] Loss on drying test: After grinding the above saponin product, pass it through a 50-mesh sieve. Accurately weigh 1.0000±0.0005g of saponin, spread it evenly in a flat weighing bottle with a thickness not exceeding 5mm, and place it in an oven at 105℃ to dry for 3 hours. After drying, remove it and place it in a desiccator to cool to room temperature, and then accurately weigh it. Then weigh it every 1 hour of drying until the weight of adjacent weighings is basically the same, that is, the difference is ±0.0003g. The final weighing value is the minimum value.

[0081] Loss on drying = Weight loss ÷ Actual weight × 100%.

[0082] The test results are shown in Table 1 below:

[0083] Table 1 Test Results

[0084]

[0085] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0086] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A saponin hydrolysis process, characterized in that, Includes the following steps: 1) Add water and acid to saponins to hydrolyze them to obtain saponins and sugars. The amount of water added is 15-25% of the mass of the saponins. 2) After hydrolysis, add solvent to extract saponin. After extraction, a solvent containing saponin and a moist solid residue are obtained. 3) The residual solvent is recovered by heating the moist solid residue, and the remaining mixture is used as fertilizer or feed; 4) Concentrate and crystallize the saponin-containing solvent obtained in step 2), collect the solid, dry it to obtain saponin, and recover the solvent for reuse.

2. The saponin hydrolysis process according to claim 1, characterized in that, The acid mentioned in step 1) is sulfuric acid or hydrochloric acid.

3. The saponin hydrolysis process according to claim 1, characterized in that, Step 1) The mass ratio of acid to water is (8-12):(88-100).

4. The saponin hydrolysis process according to claim 1, characterized in that, Step 2) The amount of solvent added is 0.8-1 times the mass of the saponin.

5. The saponin hydrolysis process according to claim 1, characterized in that, The hydrolysis temperature in step 1) is 105-115℃, and the hydrolysis time is 1.5-2.5h.

6. The saponin hydrolysis process according to claim 1, characterized in that, The solvent in step 2) is one or more of n-hexane, petroleum ether, and No. 120 gasoline.

7. The saponin hydrolysis process according to claim 1, characterized in that, After the hydrolysis in step 2) is completed, the product is dried so that the water content of the hydrolysate is less than 6%.

8. The saponin hydrolysis process according to claim 1, characterized in that, The solvent described in step 4) is first purified and then concentrated and crystallized.

9. The saponin hydrolysis process according to claim 8, characterized in that, The purification process involves adding activated carbon for adsorption.

Images