Spermidine Extraction Method

Abstract

The invention discloses a method for extracting spermidine, comprising: S1, extract preparation: taking dry powdery waste and placing it in ethanol with a volume fraction of 75%, reflux at 80-85°C for 1.5-2h, filtering to obtain an extract, the mass ratio of the powdery waste to the ethanol is 1:12-18, and the powdery waste is one of corn cobs, wheat straws, and corn straws; S2, extract preparation: placing dry powdery raw materials in the extract obtained in S1, reflux at 80-85°C for 1.5-2h and then centrifugation, taking the supernatant as the extract; the powdery raw materials are one or more of wheat germ, wolfberry, and soybean germ. The method of the present invention can make spermidine in the plant raw materials rich in spermidine escape as much as possible and make spermidine as stable as possible during the extraction process, so that the spermidine extraction rate is high, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of material extraction, and more specifically, to a method for extracting spermidine. Background Art

[0002] Spermidine, namely N-(3-aminopropyl)-1,4-butanediamine, is a polyamine that is widely found in plants, animals, bacteria, fungi and other organisms. Studies have shown that spermidine-like substances have potential antidepressant activity, so more and more scholars are studying the preparation and extraction of spermidine. At present, the preparation methods of spermidine mainly include chemical synthesis, plant extraction and biological fermentation. Among them, the plant extraction method mainly uses plants rich in spermidine as raw materials, obtains an extract by treatment with an extractant, and purifies the extract to obtain spermidine. At present, the existing plant extraction methods are still mainly water extraction and alcohol extraction, and there is a problem of low extraction rate of spermidine. Summary of the invention

[0003] An object of the present invention is to solve at least the above-mentioned problems and provide a method for extracting spermidine, which can make spermidine in a plant material rich in spermidine escape as much as possible and stabilize spermidine as much as possible during the extraction process, thereby extracting more spermidine and having good application prospects.

[0004] In order to achieve these purposes and other advantages according to the present invention, a method for extracting spermidine is provided, comprising the following steps:

[0005] S1. Preparation of extract: taking dry powdery waste and placing it in 75% ethanol by volume, reflux at 80-85° C. for 1.5-2 hours, filtering to obtain an extract, wherein the mass ratio of the powdery waste to the ethanol is 1:12-18, and the powdery waste is one of corn cobs, wheat straws, and corn straws;

[0006] S2. Preparation of extract: placing the dried powdered raw material in the extract obtained in S1, reflux at 80-85° C. for 1.5-2 hours, and then centrifugally separate, and the supernatant is the extract; the mass ratio of the powdered raw material to the extract is 1:12-18, and the powdered raw material is one or more of wheat germ, wolfberry, and soybean germ.

[0007] Preferably, in step S1, the dried powdered waste is placed in 75% by volume ethanol, refluxed at 80-85° C. for 1.5-2 hours, filtered, and the filtrate is collected, and the volume of the filtrate is concentrated to one-fifth to one-tenth of its own volume to obtain an extract.

[0008] Preferably, step S2 is performed in a dark environment.

[0009] Preferably, the powdery raw material is prepared by freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 18 to 20 hours, and then crushing the cleaned wheat germ through a 100-mesh sieve to obtain the powdery raw material.

[0010] Preferably, the powdery waste is prepared by baking the cleaned corn cobs at 55-60° C. for 4-5 hours, and then crushing them through a 60-80 mesh sieve to obtain the powdery waste.

[0011] Preferably, the method further comprises step S3, wherein the step S3 is specifically as follows: passing the extract obtained in S2 through an inorganic ceramic membrane having a pore size of 0.1-0.2 μm to obtain a clarified liquid; passing the clarified liquid through an ultrafiltration membrane having a molecular weight cutoff of 3.0-3.5 kDa to obtain a permeate; subjecting the permeate to low-temperature reduced-pressure distillation at a pressure of -0.05--0.1 MPa and a temperature of 40-50° C., and then subjecting the permeate to a first molecular distillation at a temperature of 30-40° C. and a pressure of 0.5-5 mbar, collecting heavy components and subjecting the heavy components to a second molecular distillation at a temperature of 30-40° C. and a pressure of 0.05-0.5 mbar, collecting light components, and subjecting the light components to freeze-drying at -20--30° C. for 12-24 hours to obtain pure spermidine.

[0012] The present invention has at least the following beneficial effects:

[0013] First, the powdered waste prepared from corn cobs, wheat straws, corn straws, etc. is extracted with 75% ethanol by volume to obtain an extract containing phenolic acids such as ferulic acid and p-coumaric acid. The presence of phenolic acids such as ferulic acid and p-coumaric acid makes the extract acidic. When the raw material containing spermidine is in an acidic liquid, the acidic environment of the acidic liquid helps to stabilize spermidine (it is known in the prior art that spermidine is unstable under light and alkaline environments, and is only relatively stable in an acidic environment); secondly, phenolic acids such as ferulic acid and p-coumaric acid also have strong antioxidant properties. The chemical properties can protect spermidine and prevent spermidine from being oxidized after escaping, providing a stable environment for the extraction of spermidine and keeping spermidine as stable as possible; on the whole, not only can wastes such as corn cobs, wheat straws and corn straws be reused, but the prepared extract provides a stable environment for the extraction of spermidine, which can reduce the phenomenon of spermidine being oxidized or decomposed or combined or reacted with other substances during the extraction process, which affects the extraction rate, and improves the extraction rate of spermidine as a whole (the overall relative yield of spermidine), and has good application prospects.

[0014] Second, the present invention passes the extract obtained by leaching through an inorganic ceramic membrane to remove the macromolecular impurities in the extract to obtain a clarified liquid; the clarified liquid is passed through an ultrafiltration membrane to further remove the small molecular impurities in the clarified liquid to obtain a permeate; the permeate is subjected to low-temperature reduced pressure distillation to remove the extraction solvent, and then subjected to two-step molecular distillation to obtain pure spermidine; this separation and purification method improves the purity of spermidine.

[0015] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0017] The present invention provides a method for extracting spermidine, which specifically comprises the following steps:

[0018] S1. Preparation of extract: taking dry powdery waste and placing it in 75% ethanol by volume, reflux at 80-85° C. for 1.5-2 hours, filtering to obtain an extract, wherein the mass ratio of the powdery waste to the ethanol is 1:12-18, and the powdery waste is one of corn cobs, wheat straws, and corn straws;

[0019] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 80-85°C for 1.5-2h, and centrifuging to obtain the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:12-18, and the powdered raw material is one or more of wheat germ, wolfberry, and soybean germ;

[0020] In the above technical scheme, the powdery waste is one of the wastes such as wheat straw, corn straw, and corn cob. After cleaning, the above waste is placed at 55-60°C for baking for 4-5 hours, and then crushed through a 60-80 mesh sieve to obtain powdery waste; the powdery waste is mixed with 75% ethanol by volume to make the solid-liquid ratio 1:12-18, and refluxed at 80-85°C for 1.5-2 hours to allow phenolic acid substances such as ferulic acid and p-coumaric acid in the powdery waste to escape, thereby preparing An acidic extract is obtained; the powdered raw material is placed in the extract, extracted at 80-85° C. for 1.5-2 hours, and then centrifuged to obtain a supernatant. During the extraction of the raw material, spermidine in the raw material escapes into the extract. The escaped spermidine can be kept as stable as possible under the protection of the acidic extract and phenolic acid substances such as ferulic acid, thereby improving the extraction rate of spermidine; the powdered raw material is a plant rich in spermidine, for example, it can be one or a combination of wheat germ, wolfberry, and soybean germ;

[0021] The beneficial effect obtained by adopting this technical scheme is that a method for extracting spermidine from plant raw materials rich in spermidine is provided, which not only makes waste materials such as corn cobs, wheat straws, and corn straws reused, but also the prepared extract provides a stable environment for the extraction of spermidine, and can reduce the phenomenon of spermidine being oxidized or decomposed or combined or reacted with other substances during the extraction process, which affects the extraction rate, thereby improving the extraction rate of spermidine as a whole, and has good application prospects.

[0022] In another technical solution, in step S1, the dried powdered waste is placed in 75% ethanol by volume, refluxed at 80-85°C for 1.5-2h, the filtrate is filtered and concentrated to one-fifth to one-tenth of its own volume to obtain an extract; specifically, the concentration method may be rotary evaporation to remove part of the ethanol so that the filtrate is concentrated to one-fifth to one-tenth of its own volume to obtain an extract. Such an operation can further increase the content of phenolic acid in the extract through concentration, thereby increasing the acidity of the extract, so that spermidine is more stable during extraction.

[0023] In another technical solution, step S2 is performed in a dark environment; specifically, the extraction step is performed in a dark environment. The dark environment can avoid the decomposition of spermidine caused by light, so that spermidine remains stable during the extraction process, and indirectly improves the extraction rate.

[0024] In another technical scheme, the powdered raw material is prepared by freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 18 to 20 hours, and then crushing it through a 100-mesh sieve to obtain the powdered raw material; the use of this technical scheme has the beneficial effect of selecting wheat germ as the raw material. On the one hand, wheat germ is easy to obtain, and on the other hand, it has a high spermidine content, and is very suitable as a raw material for extracting spermidine.

[0025] In another technical solution, the powdery waste is prepared by baking the cleaned corn cobs at 55-60°C for 4-5 hours, and then crushing them through a 60-80 mesh sieve to obtain the powdery waste. The technical solution has the beneficial effect of selecting corn cobs as raw materials for preparing the extract. On the one hand, corn cobs, as corn processing waste, have a very large output and are easy to obtain, so that the corn cobs can be reused. On the other hand, the phenolic acid content in the corn cobs is also relatively high, making them more suitable for preparing the extract of the present invention.

[0026] In another technical scheme, step S3 is also included, and the specific step S3 is: passing the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1-0.2 μm to obtain a clarified liquid; passing the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 3.0-3.5 kDa to obtain a permeate; first subjecting the permeate to low-temperature reduced pressure distillation at a pressure of -0.05-0.1 MPa and a temperature of 40-50° C., and then subjecting the permeate to a first molecular distillation at a temperature of 30-40° C. and a pressure of 0.5-5 mbar, collecting heavy components and subjecting the heavy components to a second molecular distillation at a temperature of 30-40° C. and a pressure of 0.05-0.5 mbar, collecting light components, and subjecting the light components to freeze-drying at -20--30° C. for 12-24 hours to obtain pure spermidine;

[0027] In this technical scheme, the extract obtained by leaching is passed through an inorganic ceramic membrane to remove the macromolecular impurities present in the extract to obtain a clarified liquid; the clarified liquid is passed through an ultrafiltration membrane to further remove the small molecular impurities in the clarified liquid to obtain a permeate; the permeate is subjected to low-temperature reduced-pressure distillation to remove the extraction solvent, and then subjected to two-step molecular distillation to obtain pure spermidine; this separation and purification method improves the purity of spermidine.

[0028] The effect of the spermidine extraction method of the present invention is described below in the form of specific embodiments.

[0029] <Example 1>

[0030] The present invention provides a method for extracting spermidine, comprising the following steps:

[0031] S1. Preparation of extract: dry powdered waste is placed in 75% ethanol by volume, refluxed at 80° C. for 2 h, and filtered to obtain an extract, wherein the mass ratio of the powdered waste to the ethanol is 1:18, and the powdered waste is corn cobs; the powdered waste is prepared by baking the cleaned corn cobs at 55° C. for 5 h, and then crushing them through an 80-mesh sieve to obtain the powdered waste;

[0032] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 80°C for 2h, centrifuging and separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:18, and the powdered raw material is wheat germ; step S2 is performed in a dark environment; the preparation of the powdered raw material is as follows: freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 20h, and then crushing and passing through a 100-mesh sieve to obtain the powdered raw material;

[0033] S. Pass the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1 μm to obtain a clarified liquid; pass the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 5 Da to obtain a permeate; first subject the permeate to low-temperature reduced-pressure distillation at a pressure of -0.05 MPa and a temperature of 40° C., and then subject it to a first molecular distillation at a temperature of 35° C. and a pressure of 0.5 mbar, collect the heavy components and subject the heavy components to a second molecular distillation at a temperature of 35° C. and a pressure of 0.05 mbar, collect the light components, and subject them to freeze-drying at -20° C. for 24 hours to obtain pure spermidine.

[0034] <Example 2>

[0035] The present invention provides a method for extracting spermidine, comprising the following steps:

[0036] S1. Preparation of extract: dry powdered waste is placed in 75% ethanol by volume, refluxed at 85° C. for 1.5 h, filtered to obtain an extract, wherein the mass ratio of the powdered waste to the ethanol is 1:12, and the powdered waste is corn stalks; the powdered waste is prepared by baking the cleaned corn stalks at 60° C. for 4 h, and then crushing them through a 60-mesh sieve to obtain the powdered waste;

[0037] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 85°C for 1.5 hours, and then centrifuging to obtain the supernatant, which is the extract; the mass ratio of the powdered raw material to the extract is 1:12, and the powdered raw material is wolfberry; step S2 is performed in a dark environment; the powdered raw material is prepared by freeze-drying the cleaned wolfberry at -60°C and a vacuum degree of 40Pa for 20 hours, and then crushing it through a 100-mesh sieve to obtain the powdered raw material;

[0038] S3. Pass the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.2 μm to obtain a clarified liquid; pass the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 10 kDa to obtain a permeate; first subject the permeate to low-temperature reduced pressure distillation at a pressure of -0.1 MPa and a temperature of 50°C, and then subject it to a first molecular distillation at a temperature of 38°C and a pressure of 1.0 mbar, collect the heavy components and subject the heavy components to a second molecular distillation at a temperature of 38°C and a pressure of 0.1 mbar, collect the light components, and subject them to freeze-drying at -30°C for 12 hours to obtain pure spermidine.

[0039] <Example 3>

[0040] The present invention provides a method for extracting spermidine, comprising the following steps:

[0041] S1. Preparation of extract: dry powdered waste is placed in 75% ethanol by volume, refluxed at 82° C. for 1.5 h, filtered to obtain an extract, wherein the mass ratio of the powdered waste to the ethanol is 1:15, and the powdered waste is wheat straw; the preparation of the powdered waste is as follows: the cleaned wheat straw is placed at 55° C. and baked for 4 h, and then crushed to pass through a 60-mesh sieve to obtain the powdered waste;

[0042] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 82°C for 1.5h, centrifuging and separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:15, and the powdered raw material is soybean germ; step S2 is performed in a dark environment; the preparation of the powdered raw material is as follows: freeze-drying the cleaned soybean germ at -55°C and a vacuum degree of 40Pa for 20h, and then crushing and passing through a 100-mesh sieve to obtain the powdered raw material;

[0043] S3, passing the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.15 μm to obtain a clarified liquid; passing the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 8 kDa to obtain a permeate; first subjecting the permeate to low-temperature reduced pressure distillation at a pressure of -0.08 MPa and a temperature of 45°C, and then subjecting the permeate to a first molecular distillation at a temperature of 40°C and a pressure of 1.0 mbar, collecting heavy components and subjecting the heavy components to a second molecular distillation at a temperature of 40°C and a pressure of 0.1 mbar, collecting light components, and subjecting the light components to freeze-drying at -25°C for 20 hours to obtain pure spermidine;

[0044] <Example 4>

[0045] The difference between Example 4 and Example 1 is that in step S1: the dried powdered waste is placed in 75% ethanol by volume, refluxed at 80-85° C. for 1.5-2 h, filtered, and the filtrate is taken, and the volume of the filtrate is concentrated to one fifth of its own volume to obtain an extract; specifically, as follows:

[0046] S1. Preparation of extract: dry powdery waste is placed in ethanol with a volume fraction of 75%, refluxed at 80-85° C. for 1.5-2 hours, filtered and the filtrate is taken, and the volume of the filtrate is concentrated to one fifth of its own volume to obtain an extract; the mass ratio of the powdery waste to the ethanol is 1:18, and the powdery waste is corn cobs; the preparation of the powdery waste is as follows: the cleaned corn cobs are placed at 55° C. and baked for 5 hours, and then crushed to pass through an 80-mesh sieve to obtain the powdery waste;

[0047] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 80°C for 2h, centrifuging and separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:18, and the powdered raw material is wheat germ; step S2 is performed in a dark environment; the preparation of the powdered raw material is as follows: freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 20h, and then crushing and passing through a 100-mesh sieve to obtain the powdered raw material;

[0048] S3. Pass the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1 μm to obtain a clarified liquid; pass the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 5 Da to obtain a permeate; first subject the permeate to low-temperature reduced pressure distillation at a pressure of -0.05 MPa and a temperature of 40°C, and then subject it to a first molecular distillation at a temperature of 35°C and a pressure of 0.5 mbar, collect the heavy components and subject the heavy components to a second molecular distillation at a temperature of 35°C and a pressure of 0.05 mbar, collect the light components, and subject them to freeze-drying at -20°C for 24 hours to obtain pure spermidine.

[0049] <Example 5>

[0050] The difference between Example 5 and Example 4 is that in step S1: the dried powdered waste is placed in 75% ethanol by volume, refluxed at 80-85° C. for 1.5-2 h, filtered, and the filtrate is taken, and the volume of the filtrate is concentrated to one eighth of its own volume to obtain an extract; specifically as follows:

[0051] S1. Preparation of extract: placing dried powdered waste in 75% ethanol by volume, reflux at 80-85° C. for 1.5-2 h, filtering and taking the filtrate, concentrating the filtrate to one eighth of its own volume, and obtaining the extract; the mass ratio of the powdered waste to the ethanol is 1:18, and the powdered waste is corn cobs; the preparation of the powdered waste is as follows: baking the cleaned corn cobs at 55° C. for 5 h, and then crushing them through an 80-mesh sieve to obtain the powdered waste;

[0052] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 80°C for 2h, centrifuging and separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:18, and the powdered raw material is wheat germ; step S2 is performed in a dark environment; the preparation of the powdered raw material is: freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 20h, and then crushing it through a 100-mesh sieve to obtain the powdered raw material;

[0053] S3. Pass the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1 μm to obtain a clarified liquid; pass the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 5 Da to obtain a permeate; first subject the permeate to low-temperature reduced pressure distillation at a pressure of -0.05 MPa and a temperature of 40°C, and then subject it to a first molecular distillation at a temperature of 35°C and a pressure of 0.5 mbar, collect the heavy components and subject the heavy components to a second molecular distillation at a temperature of 35°C and a pressure of 0.05 mbar, collect the light components, and subject them to freeze-drying at -20°C for 24 hours to obtain pure spermidine.

[0054] <Example 6>

[0055] The difference between Example 6 and Example 4 is that in step S1: the dried powdered waste is placed in 75% ethanol by volume, refluxed at 80-85° C. for 1.5-2 h, filtered, and the filtrate is taken, and the volume of the filtrate is concentrated to one tenth of its own volume to obtain an extract; specifically as follows:

[0056] S1. Preparation of extract: placing dried powdered waste in 75% ethanol by volume, reflux at 80-85° C. for 1.5-2 h, filtering and taking the filtrate, concentrating the filtrate to one tenth of its own volume, to obtain an extract; the mass ratio of the powdered waste to the ethanol is 1:18, and the powdered waste is corn cobs; the preparation of the powdered waste is as follows: baking the cleaned corn cobs at 55° C. for 5 h, and then crushing them through an 80-mesh sieve to obtain the powdered waste;

[0057] S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, refluxing at 80°C for 2h, centrifuging and separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:18, and the powdered raw material is wheat germ; step S2 is performed in a dark environment; the preparation of the powdered raw material is as follows: freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 20h, and then crushing and passing through a 100-mesh sieve to obtain the powdered raw material;

[0058] S3. Pass the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1 μm to obtain a clarified liquid; pass the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 5 Da to obtain a permeate; first subject the permeate to low-temperature reduced pressure distillation at a pressure of -0.05 MPa and a temperature of 40°C, and then subject it to a first molecular distillation at a temperature of 35°C and a pressure of 0.5 mbar, collect the heavy components and subject the heavy components to a second molecular distillation at a temperature of 35°C and a pressure of 0.05 mbar, collect the light components, and subject them to freeze-drying at -20°C for 24 hours to obtain pure spermidine.

[0059] <Comparative Example 1>

[0060] In step S1, no powdery waste is added, and the rest is the same as in Example 1.

[0061] <Determination of relative yield of spermidine>

[0062] Method: The spermidine content of the sample was detected by referring to the HPLC detection method in "GB 5009.208-2016 National Food Safety Standard Determination of Biogenic Amines in Food", and the relative yield of spermidine was calculated. The relative yield of spermidine = 100% * (the mass of spermidine in the final pure spermidine product / the mass of spermidine in the raw material); the mass of spermidine in the raw material was also determined by this method.

[0063] Sample: The content of spermidine in the pure spermidine in Examples 1 to 6 and Comparative Example 1 was measured respectively, and the relative yield of spermidine was calculated based on the measured spermidine content. Specific data are shown in Table 1.

[0064] Table 1 Relative yield of spermidine in Examples 1 to 6 and Comparative Example 1

[0065]

[0066] As can be seen from Table 1, the relative yields of spermidine in Examples 1 to 6 are much greater than the relative yield of spermidine in Comparative Example 1, indicating that the use of the extract prepared from the powdered waste of the present invention to extract spermidine in the powdered raw material can greatly improve the extraction rate of spermidine in the plant raw material rich in spermidine, and has good application prospects; at the same time, the relative yields of spermidine in Examples 4 to 6 are significantly improved compared with the relative yields of spermidine in Examples 1 to 3, indicating that by concentrating the filtrate, spermidine can be further stabilized during the extraction process, thereby improving the relative yield of spermidine.

[0067] <Determination of relative yield of spermidine before and after drying>

[0068] Method: The spermidine content of the sample was detected by referring to the HPLC detection method in "GB 5009.208-2016 National Food Safety Standard Determination of Biogenic Amines in Food", and the relative yield of spermidine in the drying process was calculated. The relative yield of spermidine in the drying process = 100%*(the mass of spermidine in the product before drying / the mass of spermidine in the product after drying). The product before drying specifically refers to the collected light fraction, and the product after drying refers to the pure spermidine.

[0069] Sample: The mass of spermidine in the products before and after drying in Examples 1 to 6 and Comparative Example 1 was measured respectively, and the relative yield of spermidine in the drying process was calculated. Specific data are shown in Table 2.

[0070] Table 2 Relative yield of spermidine in the drying step of Examples 1 to 6 and Comparative Example 1

[0071]

[0072] As can be seen from Table 2, the relative yields of spermidine in Examples 1 to 6 in the drying process are significantly greater than the relative yield of spermidine in Comparative Example 1 in the drying process, indicating that the use of the extract prepared from the powdered waste of the present invention to extract spermidine in the powdered raw material can keep the obtained spermidine as stable as possible in the drying process, thereby reducing the loss of spermidine in the drying process.

[0073] In summary, the present invention firstly utilizes 75% by volume ethanol to extract powdered waste prepared from corn cobs, wheat straws, corn straws, etc., to obtain an extract containing phenolic acids such as ferulic acid and p-coumaric acid. The presence of phenolic acids such as ferulic acid and p-coumaric acid makes the extract acidic. When the raw material containing spermidine is in an acidic liquid, the acidic environment of the acidic liquid is conducive to the stability of spermidine. Secondly, phenolic acids such as ferulic acid and p-coumaric acid also have strong antioxidant properties, which can protect spermidine and avoid spermidine. It is oxidized after escaping, which provides a stable environment for the extraction of spermidine and can keep spermidine as stable as possible; on the whole, not only can waste materials such as corn cobs, wheat straws, and corn straws be reused, but the prepared extract provides a stable environment for the extraction of spermidine, which can reduce the phenomenon of spermidine being oxidized or decomposed or combining or reacting with other substances during the extraction process, which affects the extraction rate, and improves the extraction rate of spermidine (relative yield of spermidine) as a whole, and has good application prospects.

[0074] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for extracting spermidine, characterized in that: The following steps are involved: S1. Preparation of extract: taking dry powdery waste and placing it in 75% ethanol by volume, reflux at 80-85° C. for 1.5-2 hours, filtering to obtain an extract, wherein the mass ratio of the powdery waste to the ethanol is 1:12-18, and the powdery waste is one of corn cobs, wheat straws, and corn straws; S2, preparation of extract: placing the dried powdered raw material in the extract obtained in S1, reflux at 80-85°C for 1.5-2h, and centrifugally separating, and taking the supernatant as the extract; the mass ratio of the powdered raw material to the extract is 1:12-18, and the powdered raw material is one or more of wheat germ, wolfberry, and soybean germ; step S2 is performed in a dark environment; The method further includes step S3, which specifically comprises: passing the extract obtained in S2 through an inorganic ceramic membrane with a pore size of 0.1-0.2 μm to obtain a clarified liquid; passing the clarified liquid through an ultrafiltration membrane with a molecular weight cutoff of 3.0-3.5 kDa to obtain a permeate; first subjecting the permeate to low-temperature reduced-pressure distillation at a pressure of -0.05--0.1 MPa and a temperature of 40-50° C., and then subjecting the permeate to a first molecular distillation at a temperature of 30-40° C. and a pressure of 0.5-5 mbar, collecting heavy components and subjecting the heavy components to a second molecular distillation at a temperature of 30-40° C. and a pressure of 0.05-0.5 mbar, collecting light components, and subjecting the light components to freeze-drying at -20--30° C. for 12-24 hours to obtain pure spermidine.

2. The method for extracting spermidine as claimed in claim 1, wherein In step S1, the dried powdered waste is placed in 75% by volume ethanol, refluxed at 80-85° C. for 1.5-2 hours, filtered, and the filtrate is collected, and the volume of the filtrate is concentrated to one-fifth to one-tenth of its own volume to obtain an extract.

3. The method for extracting spermidine as claimed in claim 1, wherein The powdery raw material is prepared by freeze-drying the cleaned wheat germ at -55°C and a vacuum degree of 40Pa for 18-20h, and then crushing the cleaned wheat germ through a 100-mesh sieve to obtain the powdery raw material.

4. The method for extracting spermidine as claimed in claim 1, wherein The powdery waste is prepared by baking the cleaned corn cobs at 55-60° C. for 4-5 hours, and then crushing them through a 60-80 mesh sieve to obtain the powdery waste.

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