Method for extracting sodium alginate by utilizing irradiation technology to treat seaweed

Abstract

The invention discloses a method for extracting sodium alginate by treating seaweed through an irradiation technology. The extraction process comprises the steps that sodium alginate is extracted from the seaweed through an acid coagulation-acidification method, a calcium coagulation-acidification method, a calcium coagulation-ion exchange method, an enzymolysis method, an ultrafiltration method or a microwave-assisted extraction method, and before the digestion step, irradiation treatment with the dosage of 0-100 kGy is conducted on the seaweed. According to the method, before the digestion step, the irradiation method is adopted for auxiliary treatment of the seaweed to extract the sodium alginate, the seaweed subjected to irradiation treatment is softened, molecular chain breakage is generated, digestion is facilitated, and the extraction efficiency of the sodium alginate can be improved. The high-energy rays can reduce the average molecular weight of sodium alginate in the seaweed and reduce the molecular weight distribution width, and sodium alginate with small molecular weight can be directly extracted from the seaweed, so that the sodium alginate can be well absorbed by a human body and has an excellent medical health care function.

Description

Technical Field

[0001] The invention relates to the technical field of natural polymer extraction, and in particular to a method for extracting sodium alginate by treating seaweed with irradiation technology. Background Art

[0002] Sodium alginate is an important natural polysaccharide polymer, which is widely used in food, medicine, cosmetics and other fields. It has excellent thickening, film-forming and gelling properties. The human body cannot absorb sodium alginate with a large molecular weight, but when the molecular weight of sodium alginate drops to a certain range, it is easily absorbed by the human body and has excellent medical and health functions.

[0003] The main methods for extracting sodium alginate are acid coagulation-acidification method, calcium coagulation-acidification method, calcium coagulation-ion exchange method, enzymatic hydrolysis-extraction method, etc. In the process of preparing sodium alginate from kelp, it is necessary to go through the steps of pretreatment, digestion, filtration, calcification, decalcification, drying, etc. In the related art, there is a method for extracting sodium alginate using high-pressure homogenization, such as the Chinese invention patent CN 113061196 B, which uses high-pressure homogenization to perform multiple ultra-fine refinements on kelp powder, and reduces the digestion reaction time by adding EDTA, thereby solving the problem of low extraction efficiency and low production efficiency of sodium alginate. However, it is impossible to directly obtain sodium alginate with a smaller molecular weight. For example, the Chinese invention patent application CN 101979522 A discloses a compound enzyme formula and application for improving the extraction rate of sodium alginate, which uses protease, pectinase, cellulase, and xylanase in a scientific ratio to prepare a compound enzyme, pre-treats the raw materials, and then uses traditional chemical methods to produce sodium alginate. The application states that the extraction rate and viscosity of sodium alginate can be improved, and the amount of chemicals used can be reduced. However, it is expensive and contains more impurities. Summary of the invention

[0004] To solve the above problems, the present invention provides a method for extracting sodium alginate by treating seaweed with irradiation technology. The method prepares sodium alginate by treating seaweed with irradiation technology, can directly produce sodium alginate with a smaller molecular weight, and maintain the extraction rate of sodium alginate.

[0005] According to a method of extracting sodium alginate by treating seaweed with irradiation technology of the present invention, the method adopts irradiation method to assist in treating seaweed to extract sodium alginate before the digestion step, and the seaweed after irradiation treatment is helpful for digestion and can improve the extraction efficiency of sodium alginate. Seaweed, as a natural food, is rich in a variety of nutrients that are beneficial to the human body. Its main nutrients include protein, fat, minerals, vitamins and dietary fiber, among which the protein content in seaweed is relatively high, and it contains essential amino acids for the human body, which plays an important role in supplementing the protein of the human body. High-energy ray treatment of seaweed can obtain low molecular weight sodium alginate and can reduce the molecular weight distribution width, so that sodium alginate can be well absorbed by the human body and has excellent medical and health care functions. In addition, irradiation treatment technology is environmentally friendly, cost-effective, has high treatment efficiency, low energy consumption, and a safe and controllable treatment process.

[0006] The embodiment of the present invention provides a method for extracting sodium alginate by treating seaweed with irradiation technology, which comprises:

[0007] Sodium alginate is extracted from seaweed by acid coagulation-acidification method, calcium coagulation acidification method, calcium coagulation-ion exchange method, enzymatic hydrolysis method, ultrafiltration method or microwave-assisted extraction method, wherein before the digestion step, the seaweed is irradiated with a dose of 0kGy-100kGy (high-energy electron beam irradiation, cobalt-60γ irradiation).

[0008] Optionally, prior to the digestion step, irradiation treatment at a dose of 40 kGy-60 kGy is used.

[0009] Optionally, the following steps are included:

[0010] (1) soaking the dried seaweed in water to make the algae swell and soften, then soaking in formaldehyde solution to fix the seaweed pigment in the epidermal cells, and filtering, washing and drying after the soaking;

[0011] (2) After irradiation treatment, the dried seaweed is placed in a Na2CO3 solution for heating and digestion at a temperature range of 30°C to 80°C. After the reaction, it is diluted with water and filtered to obtain an alginate gel solution;

[0012] (3) Adding calcium chloride solution to the alginate gel solution for calcium precipitation, and adding hydrochloric acid to adjust the pH of the alginate gel solution to 6.0-7.0 to obtain calcium alginate; wherein, calcium precipitation can be replaced by ion exchange, that is, the calcium alginate gel is put into 6 times the volume of NaCl solution, stirred at room temperature for 60 minutes, and the NaCl solution is filtered out, that is, the first exchange is completed, and the above process is repeated 5 to 6 times. Citric acid or oxalic acid can also be used to adjust the pH.

[0013] (4) adding hydrochloric acid to the calcium alginate for acidification, and taking out the clot after standing for 30 minutes;

[0014] (5) adding the coagulated mass to a Na2CO3 solution, allowing the solution to stand until the blocky coagulated mass is completely transformed into a dispersed flocculent gel, and filtering out the residue; adding ethanol to the residue, allowing the solution to stand, and then filtering out the residue; adding ethanol again to wash the residue, and then filtering out the residue; repeating the washing steps, and obtaining a colloid-like object after filtering out the residue;

[0015] (6) Drying and crushing the colloidal substance to obtain sodium alginate.

[0016] Optionally, in step (1), the formaldehyde solution is analytical grade formaldehyde reagent diluted 80-150 times.

[0017] Optionally, in step (1), the drying is performed by placing the product in an oven at 60° C. to 80° C. for 24 h to 36 h.

[0018] Optionally, in step (2), the concentration of the Na2CO3 solution is 1.0%-4.0%, and the reaction time is 2h-6h.

[0019] Optionally, in step (2), the dried seaweed is irradiated with a dose of 0 kGy-100 kGy.

[0020] Optionally, in step (3), the concentration of the calcium chloride solution is 6%-10%.

[0021] Optionally, the concentration of the hydrochloric acid is 5%-15%.

[0022] Optionally, in step (5), the concentration of the Na2CO3 solution is 5%-15%; the concentration of the ethanol is 75%-100%.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a picture of a finished sodium alginate product prepared according to an embodiment of the present invention;

[0025] Figure 2 This is a scanning electron microscope image of sodium alginate prepared according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0027] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0028] The test materials used in the present invention are all common commercial products and can be purchased in the market.

[0029] In the following examples, Laminaria japonica was used as the seaweed for the test.

[0030] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0033] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0034] The test materials used in the present invention are all common commercial products and can be purchased in the market.

[0035] In the following examples, Laminaria japonica was used as the seaweed for the test.

[0036] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0037] Example 1

[0038] A method for extracting sodium alginate by irradiating seaweed, comprising the following steps:

[0039] (1) Soaking and drying

[0040] Take 102.25g of dried kelp and soak it in water 10 times the weight of the dried kelp for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the kelp pigment in the epidermal cells, so that it will not dissolve in water and cause the product color to deepen. After soaking, filter, wash, drain, and place in an oven at 80℃ for 5 hours to control the water content of the kelp to 25%-35%.

[0041] (2) Digestion

[0042] The treated kelp was irradiated with a dose of 25 kGy, and then placed in 500 mL of Na2C03 with a mass concentration of 1.5%, and heated in a 35°C water bath for 4 hours; after digestion, the kelp soaking liquid was gelatinous, and it was diluted to 2000 mL with pure water; it was filtered three times with 100 mesh gauze; the filtrate was filtered for 8 hours to obtain alginate gel solution.

[0043] The irradiation is performed using an electron accelerator irradiation processing system; the irradiation parameters are: average beam intensity 2 mA, scanning width 300-800 mm, and surface irradiation unevenness ≤±5%.

[0044] (3) Calcium precipitation

[0045] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0046] (4)Acidification

[0047] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0048] (5) Replacement and purification

[0049] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0050] (6) Drying and crushing

[0051] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0052] Example 2

[0053] A method for extracting sodium alginate by irradiating seaweed, comprising the following steps:

[0054] (1) Soaking and drying

[0055] Take 102.25g of Ascophyllum nodosum and soak it in water at 10 times its weight for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the pigment of Ascophyllum nodosum in the epidermal cells, so that it will not dissolve in water and cause the color of the product to deepen. After soaking, filter, wash, drain, and place in an oven at 80℃ for 5 hours to control the water content of Ascophyllum nodosum to be 25%-35%.

[0056] (2) Digestion

[0057] The treated Ascophyllum nodosum was irradiated with a dose of 50 kGy, and then placed in 500 mL of Na2C03 with a mass concentration of 1.5%, and heated in a 35°C water bath for 4 hours; after digestion, the Ascophyllum nodosum soaking liquid was in a gelatinous state, and was diluted to 2000 mL with pure water; it was filtered three times with 100 mesh gauze; the filtrate was filtered for 8 hours to obtain alginate gel solution.

[0058] The irradiation is performed using an electron accelerator irradiation processing system, and the irradiation parameters are: average beam intensity 2 mA, scanning width 300-800 mm, and surface irradiation unevenness ≤±5%.

[0059] (3) Calcium precipitation

[0060] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0061] (4)Acidification

[0062] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0063] (5) Replacement and purification

[0064] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0065] (6) Drying and crushing

[0066] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0067] Example 3

[0068] A method for extracting sodium alginate by irradiating seaweed, comprising the following steps:

[0069] (1) Soaking and drying

[0070] Take 102.25g of Sargassum and soak it in water at 10 times its weight for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the Sargassum pigment in the epidermal cells, so that it will not dissolve in water and cause the product color to deepen. After soaking, filter, wash, drain, and place in an oven at 80℃ for 5 hours to control the water content of the Sargassum to 25%-35%.

[0071] (2) Digestion

[0072] After the treated Sargassum is irradiated with a dose of 75 kGy, it is placed in 500 mL of Na2C03 with a mass concentration of 1.5%, and heated in a 75°C water bath for 4 hours; after digestion, the Sargassum soaking liquid is colloid, and it is diluted to 2000 mL with pure water; it is filtered three times with 100 mesh gauze; the filtrate is filtered for 8 hours to obtain alginate gel. Among them, the irradiation is performed using an electron accelerator irradiation processing system, and the irradiation parameters are: average beam intensity 2 mA, scanning width 300-800 mm, and surface irradiation unevenness ≤ ± 5%.

[0073] (3) Calcium precipitation

[0074] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0075] (4)Acidification

[0076] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0077] (5) Replacement and purification

[0078] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0079] (6) Drying and crushing

[0080] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0081] Example 4

[0082] A method for extracting sodium alginate by irradiating seaweed, comprising the following steps:

[0083] (1) Soaking and drying

[0084] Take 102.25g of dry kelp and soak it in water 10 times its weight for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the kelp pigment in the epidermal cells, so that it will not dissolve in water and cause the product color to deepen. After soaking, filter, wash, drain, and place in an oven at 80℃ for 5 hours to control the water content of the kelp to 25%-35%.

[0085] (2) Digestion

[0086] After the processed kelp is irradiated with a dose of 100 kGy, it is placed in 500 mL of Na2C03 with a mass concentration of 1.5%, and heated in a 35°C water bath for 4 hours; after digestion, the kelp soaking liquid is colloid, and it is diluted to 2000 mL with pure water; it is filtered three times with 100 mesh gauze; the filtrate is filtered for 8 hours to obtain alginate gel. Among them, the irradiation is performed using an electron accelerator irradiation processing system, and the irradiation parameters are: average beam intensity 2 mA, scanning width 300-800 mm, and surface irradiation unevenness ≤±5%.

[0087] (3) Calcium precipitation

[0088] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir for 30 minutes until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0089] (4)Acidification

[0090] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0091] (5) Replacement and purification

[0092] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0093] (6) Drying and crushing

[0094] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0095] Example 5

[0096] A method for extracting sodium alginate by treating seaweed, comprising the following steps:

[0097] (1) Soaking and drying

[0098] Take 102.25g of dried kelp and soak it in water 10 times the weight of the dried kelp for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the kelp pigment in the epidermal cells, so that it will not dissolve in water and cause the product color to deepen. After soaking, filter, wash and drain, and place in an oven at 80℃ for 5 hours to control the water content of the kelp to 25%-35%.

[0099] (2) Digestion

[0100] The treated kelp is not irradiated (i.e., the irradiation dose is 0 kGy), and then placed in 500 mL of 1.5% Na2CO3, and heated in a 35°C water bath for 4 hours; after digestion, the kelp soaking liquid is gelatinous, and it is diluted to 2000 mL with pure water; it is filtered three times with 100 mesh gauze; the filtrate is filtered for 8 hours to obtain alginate gel. Among them, the irradiation is performed using an electron accelerator irradiation processing system, and the irradiation parameters are: average beam intensity 2 mA, scanning width 300-800 mm, surface irradiation unevenness ≤ ± 5%;

[0101] (3) Calcium precipitation

[0102] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir for 30 minutes until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0103] (4)Acidification

[0104] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0105] (5) Replacement and purification

[0106] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0107] (6) Drying and crushing

[0108] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0109] Example 6

[0110] A method for extracting sodium alginate by treating seaweed, comprising the following steps:

[0111] (1) Soaking and drying

[0112] Take 102.25g of dried kelp and soak it in water 10 times the weight of the dried kelp for 4 hours to make the algae swell and soften, and add 300mL of formaldehyde solution (40% formaldehyde diluted 100 times) and soak it for 5 hours to fix the kelp pigment in the epidermal cells, so that it will not dissolve in water and cause the product color to deepen. After soaking, filter, wash and drain, and place in an oven at 80℃ for 5 hours to control the water content of the kelp to 25%-35%.

[0113] (2) Digestion

[0114] The treated kelp was irradiated with cobalt-60 gamma rays at a dose of 10 kGy, and then placed in 500 mL of Na2C03 with a mass concentration of 1.5%, and heated in a 35°C water bath for 4 hours; after digestion, the kelp soaking liquid was gelatinous, and it was diluted to 2000 mL with pure water; it was filtered three times with 100 mesh gauze; the filtrate was filtered for 8 hours to obtain alginate gel solution.

[0115] (3) Calcium precipitation

[0116] Add 500mL of 10% CaCl2 solution to the alginate gel solution, and at the same time add 150mL of 10% HCl to the alginate gel solution to ensure that the pH value of the gel solution is 6.0-7.0 during calcium precipitation, and stir for 30 minutes until the alginate solution is completely condensed into calcium alginate in the form of clots. Through this step, the alginate gel solution is condensed into calcium alginate.

[0117] (4)Acidification

[0118] 500 mL of 10% hydrochloric acid was added to the calcium alginate for acidification, and the mixture was allowed to stand for 30 minutes.

[0119] (5) Replacement and purification

[0120] The acidified calcium alginate was filtered, and the filtered coagulated mass was added with 200 mL of 10% Na2CO3, and allowed to stand at 40°C until the blocky precipitated gel was completely transformed into dispersed flocculent gel, and the residue was filtered. The residue was added with 100 mL of 95% ethanol, and stirred for about 30 minutes to completely precipitate the flocculent matter, and the residue was filtered out by suction, and 95% ethanol was added again for washing, and the residue was filtered out by suction, and the washing steps were repeated to obtain a colloid-like object after filtration.

[0121] (6) Drying and crushing

[0122] The colloid-like substance is placed in an oven at 80°C and dried for 24 hours, and then crushed to obtain a white powdery sodium alginate product. Figure 1 shown.

[0123] Test example

[0124] The sodium alginate obtained in the above example was scanned by electron microscope. The results are as follows: Figure 2 As shown, the fiber structure of kelp after irradiation is loose. With the increase of absorbed dose, the degree of breakage of the internal molecular chain of kelp increases, the molecular chain becomes shorter, the molecular weight becomes smaller, and the increase of cross-linking effect destroys the cell structure of kelp. The viscosity-average molecular weight of the above-mentioned Examples 1-5 and commercially available sodium alginate (Qingdao Mingyue Seaweed Group) was measured. The instrument is an Ubbelohde viscometer, and the test method is: accurately weigh 0.2g of sodium alginate dried at 105°C for 6h, place it in about 50ml of 0.1mol / L NaCl solution (containing 0.05% disodium ethylenediaminetetraacetic acid), dissolve it after 24h and dilute it to 100mL, and determine the intrinsic viscosity (n) according to the second method of 0633 of the fourth general rule of the Pharmacopoeia of the People's Republic of China (2015 edition) (temperature controlled at 20°C ± 0.05°C), where K = 2.0×10 -5 , a=1, substitute it into Mark-Houwink-Sakurada equation, and the average molecular weight of sodium alginate can be calculated.

[0125] The results are shown in Table 1. The viscosity average molecular weight of sodium alginate increases with the increase of irradiation dose, but the viscosity average molecular weight decreases significantly after reaching 75k. Among them, the sodium alginate after 100kGy irradiation is obviously insoluble, and there are still many insolubles after ultrasound. Compared with the commercially available reference product, the viscosity average molecular weight of the sodium alginate extracted in this application is lower.

[0126] Table 1 Viscosity average molecular weight and yield of sodium alginate

[0127]

[0128]

[0129] In summary, according to the embodiments of the present invention, irradiation is used to assist in the treatment of seaweed to extract sodium alginate before the digestion step. The seaweed is softened after being irradiated with a high-energy electron beam or cobalt-60 gamma rays, and some impurities are eliminated, which helps digestion and ensures the efficiency of sodium alginate. In addition, radiation reduces the average molecular weight of sodium alginate in seaweed and reduces the molecular weight distribution width, so that sodium alginate with a smaller molecular weight can be directly extracted from the seaweed, so that the sodium alginate can be well absorbed by the human body and has excellent medical and health care functions.

[0130] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0131] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for extracting sodium alginate by treating seaweed with irradiation technology, characterized in that: include: Sodium alginate is extracted from the seaweed by acid coagulation-acidification method, calcium coagulation acidification method, calcium coagulation-ion exchange method, enzymatic hydrolysis method, ultrafiltration method or microwave-assisted extraction method, wherein, before the digestion step, the seaweed is irradiated with a dose of 0kGy-100kGy.

2. The method according to claim 1, characterized in that Prior to the digestion step, the cells were irradiated with high energy electron beam or cobalt-60 gamma rays at a dose of 0 kGy-100 kGy.

3. The method according to claim 1, characterized in that The following steps are involved: (1) soaking the dried seaweed in water to make the algae swell and soften, then soaking in formaldehyde solution to fix the seaweed pigment in the epidermal cells, and filtering, washing and drying after the soaking; (2) irradiating the dried seaweed and then placing it in a Na2CO3 solution for digestion reaction. After the reaction, diluting it with water and filtering it to obtain alginate gel solution; (3) adding a calcium chloride solution to the alginate solution for calcium precipitation, and adding hydrochloric acid to adjust the pH of the alginate solution to obtain calcium alginate; (4) adding hydrochloric acid to the calcium alginate to acidify it, and collecting a clot after standing; (5) adding the coagulated mass to a Na2CO3 solution, allowing the solution to stand until the blocky coagulated mass is completely transformed into a dispersed flocculent gel, and filtering out the residue; adding ethanol to the residue, allowing the solution to stand, and then filtering out the residue; adding ethanol again to wash the residue, and then filtering out the residue; repeating the washing steps, and obtaining a colloid-like object after filtering out the residue; (6) Drying and crushing the colloidal substance to obtain sodium alginate.

4. The method according to claim 3, characterized in that In step (1), the formaldehyde solution is analytical grade formaldehyde reagent diluted 80-150 times.

5. The method according to claim 3, characterized in that In step (1), the drying step is performed in an oven at 50°C-100°C for 12h-36h.

6. The method according to claim 3, characterized in that In step (2), the concentration of the Na2CO3 solution is 1.0%-4.0%, and the reaction time is 2h-6h.

7. The method according to claim 3, characterized in that In step (2), the dried seaweed is irradiated with a dose of 0 kGy to 100 kGy.

8. The method according to claim 3, characterized in that In step (3), the concentration of the calcium chloride solution is 6%-10%.

9. The method according to claim 3, characterized in that In step (5), the concentration of the Na2CO3 solution is 5%-15%; the concentration of the ethanol is 75%-100%.

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