Process for gradient extraction of seaweed protein, algin and fucoidin in brown algae

Abstract

The invention relates to a process for gradient extraction of seaweed protein, algin and fucoidin in brown algae. The invention relates to a process for extracting seaweed protein, algin and fucoidin in brown algae, which comprises the following steps: carrying out superfine grinding on seaweed, adding water for extraction, filtering and separating to obtain water extraction filtrate, repeatedly dissolving the water extraction filtrate in the next batch of superfine ground seaweed, and circulating for 7 times to obtain saturated or supersaturated water extraction filtrate; adjusting the pH value of the water extraction filtrate to be acidic, and filtering and separating through a micro-filtration membrane to obtain seaweed protein and first filtrate; adding calcium chloride into the first filtrate, and settling to obtain algin and supernate; filtering the supernate through a polyethersulfone composite membrane to obtain a fucoidin concentrated solution; and carrying out spray drying on the concentrated solution to obtain fucoidin powder. The method solves the problem that other functional components are wasted due to the fact that only a single component can be extracted in an existing brown algae functional component extraction method, and also solves the problems of secondary pollution, poor product quality and high cost in an existing extraction method.

Description

Technical Field

[0001] The invention relates to the technical field of algae extraction and processing, and in particular to a process for stepwise extraction of algae protein, alginate and fucoidan from brown algae. Background Art

[0002] Large algae contain rich functional nutrients and secondary metabolites. These active substances are mainly composed of seaweed protein, alginate, fucoidan, small molecule fucoidan, carotenoids, vitamins, fatty acids and steroids, which endow algae with multiple functional properties such as antioxidant, anti-tumor, anti-coagulation, anti-inflammatory, anti-diabetic and anti-microbial. Algae carbohydrates have high utilization value. However, in the field of food production, current separation and purification technologies mainly rely on traditional processes such as solvent precipitation, centrifugation, and thermal concentration. These methods are prone to cause the loss of nutrients and flavor substances, resulting in a decline in product quality and limiting the full play of functional factors.

[0003] At present, the extraction methods of seaweed protein are mainly aimed at the extraction of single protein components, including ultrasonic crushing, freeze-thaw method, swelling method, alkaline water method, solvent extraction method, etc. The ultrasonic crushing method is to mix algae cells with water to form a suspension, and then use an ultrasonic processor to crush them. Although this method has the advantages of short experimental cycle and high cell crushing rate, it has high energy consumption and may cause protein denaturation due to increased heat. The freeze-thaw method freezes the cells at low temperature for a period of time and then melts them at room temperature, repeating the operation many times, using the formation of ice particles and the increase in cytosolic salt concentration to cause cell swelling and crushing. Although this method is simple to operate, it takes a long time to scale up production. The swelling method soaks spirulina dry powder in an aqueous solution, uses the difference in osmotic pressure inside and outside the cell to break the cell wall and release phycocyanin. This method has simple equipment but takes a long time. The alkaline water method crushes the spirulina cells, adds sodium hydroxide to make the solution alkaline, destroys the cell membrane to release pigments, and then separates insoluble substances by centrifugation or filtration, and finally purifies phycocyanin by crystallization. This method is simple and easy, but it causes great damage to cells and can easily affect product quality. The solvent extraction method involves breaking the cells, mixing them with an organic solvent (such as ethanol, ether), stirring and filtering to obtain a pigment-containing solution, and finally separating the phycocyanin through crystallization. This method is suitable for situations where higher quality extracts are required, but it requires the use of organic solvents, which poses environmental and health risks. The extraction methods for single alginate include water extraction and acid extraction. The water extraction method utilizes the property of alginate being easily soluble in water, and avoids the possibility of acid hydrolysis through water extraction. However, this method has the disadvantages of too large an extract volume, a large amount of alginate in the extract, and difficulty in separation and purification. The acid extraction method utilizes the property of alginate being difficult to dissolve at low pH, and uses dilute hydrochloric acid to extract alginate. Although this method can obtain alginate of higher purity, it has the disadvantages of long extraction cycle, difficulty in removing chemicals, and high energy consumption. Compared with the traditional hot water extraction method, the extraction rate of the ultrasonic-assisted extraction method increased by 67.25% The extraction methods for single fucoidan include water extraction, acid extraction and enzymatic assisted extraction. The water extraction method dissolves the polysaccharide in water by heating, and then obtains crude fucoidan through filtration, purification and other steps. Although the water extraction method avoids the possibility of acid hydrolysis of fucoidan, this method has the disadvantages of too large volume of extract, more alginate in the extract, and difficulty in separation and purification. The acid extraction method separates fucoidan from brown algae by utilizing the selective dissolution ability of dilute hydrochloric acid solution. Although the purity of fucoidan in the extract is high in this method, it has the disadvantages of long extraction cycle, difficult removal of chemicals and high energy consumption. The enzymatic assisted extraction method uses specific enzymes (such as cellulase) to enzymatically hydrolyze brown algae to make fucoidan easier to extract. This method usually needs to be used in combination with other extraction methods, and has the disadvantages of low enzymatic efficiency and low yield. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a process for the stepwise extraction of seaweed protein, alginate and fucoidan from brown algae, so as to solve the problem that the existing method for extracting functional components of algae can only extract a single component, resulting in waste of other functional components, and also to solve the problems of secondary pollution, poor product quality and high cost in the existing extraction method.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A process for stepwise extraction of algae protein, alginate and fucoidan from brown algae comprises the following steps: S1, ultrafinely pulverizing the brown algae, then extracting with water, filtering and separating to obtain a water extract filtrate, and repeatedly dissolving the ultrafinely pulverized brown algae in the water extract filtrate to obtain a saturated or supersaturated water extract filtrate; S2, adjusting the pH value of the saturated or supersaturated water filtrate to acidic, filtering and separating through a microfiltration membrane to obtain seaweed protein and a first filtrate; S3, adding calcium chloride to the first filtrate, allowing sedimentation to obtain alginate and a supernatant; S4. Filter the supernatant through a polyethersulfone (PES) composite membrane to remove free heavy metals and small molecular impurities to obtain a fucoidan concentrate.

[0006] S5. Spray-drying the fucoidan concentrate to obtain pure fucoidan powder.

[0007] According to the above-mentioned technical means, first, by ultrafinely grinding brown algae and recycling water extract, not only the effective rupture of brown algae cells is ensured, so that the biologically active ingredients such as seaweed protein, alginate and fucoidan are more easily dissolved, but also the nutrients in brown algae can be fully released, the extraction efficiency is improved, and water use is reduced by 80%. Secondly, by adjusting the pH value of the water extract filtrate to acidic, and filtering and separating by microfiltration membrane, not only the effective separation of protein and the first filtrate is effectively achieved, but also the purity of protein is ensured, the pollution problem in the subsequent treatment process is avoided, and the quality of the final product is ensured. Furthermore, calcium chloride is added to the first filtrate for sedimentation, and calcium chloride is combined with alginate to form a precipitate, which not only efficiently separates alginate, but also ensures the biological activity of alginate, and the precipitate formed by calcium chloride and alginate is easy to separate, which provides a good basis for subsequent applications. Finally, the supernatant was filtered using a polyethersulfone (PES) composite membrane, which has excellent separation performance and chemical stability, and can filter out free heavy metals and small molecular impurities, accurately separate fucoidan from the concentrate, ensure the purity and quality of fucoidan, and meet various application requirements. At the same time, the above process effectively realizes the step-by-step separation of multiple functional components, ensures the full application of each functional component, avoids the use of organic solvents, reduces secondary pollution, and avoids subsequent processing costs.

[0008] Preferably, S1 specifically includes: ultrafinely grinding the brown algae, adding it to water, filtering and separating to remove the residue, obtaining a water extract filtrate, and repeatedly dissolving the next batch of ultrafinely ground brown algae in the water extract filtrate, and repeating the cycle to make the water extract filtrate reach a saturated or supersaturated state, thereby obtaining a saturated or supersaturated water extract filtrate.

[0009] Preferably, the water extraction filtrate is circulated at least 7 times to obtain the saturated or supersaturated water extraction filtrate. Such a cycle (i.e., adding the extract again instead of adding new water each time) effectively reduces the amount of water used. Experiments have shown that the amount of water used can be reduced by 80%.

[0010] The use of circulating supersaturated water extraction effectively promotes the formation of saturated or supersaturated dissolution of carbohydrates and proteins.

[0011] Preferably, in S2, an acid is used to adjust the pH value of the saturated or supersaturated water filtrate to 1.8-4.5.

[0012] Preferably, the acid is selected from at least one of citric acid, hydrochloric acid and acetic acid.

[0013] Preferably, the microfiltration membrane is selected from ceramic microfiltration membranes.

[0014] Preferably, the pore size of the ceramic microfiltration membrane is 0.5 micrometer, and the flow rate of the saturated or supersaturated water filtrate through the ceramic microfiltration membrane is 15-200 L / h.

[0015] Preferably, in S3, calcium chloride is added to the first filtrate so that the content of calcium chloride in the first filtrate is 1.5-2%.

[0016] Preferably, in S3, after sedimentation, a disc centrifuge is used for centrifugal separation at a speed of 13500-14500g, that is, the centrifugal speed reaches 13500-14500 of gravity, to obtain alginate and a supernatant.

[0017] Preferably, S4 specifically comprises: filtering the supernatant with a polyethersulfone (PES) composite membrane having a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h, and concentrating to obtain a fucoidan concentrate.

[0018] By using 500~1000 Dalton polyethersulfone (PES) composite membrane for filtration, macromolecular substances such as algae polysaccharides in the supernatant can be effectively retained, while allowing small molecular impurities such as salts, inorganic substances and free heavy metals to pass through, thereby achieving the purpose of algae polysaccharide concentration and effectively removing impurities. In addition, the polyethersulfone (PES) composite membrane has good selective permeability and stability, ensuring filtration efficiency and concentration effect.

[0019] Preferably, S5 specifically includes: centrifugally spray-drying the fucoidan concentrate at a rotation speed of 25,000 rpm to obtain fucoidan powder.

[0020] Spray drying of the fucoidan concentrate can not only remove the water in the concentrate, but also further remove some volatile impurities, effectively improving the purity of the fucoidan.

[0021] Preferably, the drying adopts centrifugal spray drying to dry the algae polysaccharide concentrate, and the centrifugal atomization speed is 25000 rpm.

[0022] Preferably, the brown algae is selected from at least one of Undaria pinnatifida, Laminaria japonica, Sargassum fusiformis and Sargassum.

[0023] Beneficial effects of the present invention: The process of the step extraction of seaweed protein, alginate and fucoidan in brown algae of the present invention, first, by ultrafine grinding of brown algae wet method and circulating to supersaturated water extraction, not only the effective rupture of brown algae cells is ensured, so that biologically active components such as seaweed protein, alginate and fucoidan are more easily dissolved, but also the nutrients in brown algae can be fully released, and the extraction efficiency is improved. Secondly, by adjusting the pH value of the water extraction filtrate to acidic, and filtering and separating by microfiltration membrane, not only the effective separation of protein and the first filtrate is effectively achieved, but also the purity of seaweed protein is ensured, and the pollution problem in the subsequent treatment process is avoided, and the quality of the final product is ensured. Furthermore, calcium chloride is added to the first filtrate for sedimentation, and calcium chloride is combined with alginate to form a precipitate, which not only efficiently separates alginate, but also ensures the biological activity of alginate, and the precipitate formed by calcium chloride and alginate is easy to separate, which provides a good basis for subsequent application. Finally, the supernatant is filtered using a polyethersulfone (PES) composite membrane, which has excellent separation performance and chemical stability, so that fucoidan can be accurately separated, ensuring the purity and quality of fucoidan and meeting various application requirements. At the same time, the above process effectively realizes the step-by-step separation of multiple functional components, ensures the full application of each functional component, avoids the use of organic solvents, reduces secondary pollution, saves water and corresponding costs, and avoids subsequent processing costs. In summary, the process of the present invention has the advantages of high extraction efficiency, high product purity, low cost, and simple operation. It provides strong support for the comprehensive development and utilization of fucoidan resources and has great promotion and application value in the field of algae extraction and processing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the process of stepwise extraction of algal protein, alginate and fucoidan from brown algae. DETAILED DESCRIPTION

[0025] The following will describe the embodiments of the present invention with reference to the preferred embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0026] The present invention is intended to disclose a process for stepwise extraction of seaweed protein, alginate and fucoidan from brown algae, so as to solve the problem that the existing method for extracting functional components of algae can only extract a single component, resulting in waste of other functional components, and can also solve the problems of secondary pollution, poor product quality and high cost in the existing extraction method.

[0027] The process of stepwise extraction of algae protein, alginate and fucoidan from brown algae comprises the following steps: S1, ultrafinely pulverizing the brown algae, then extracting with water, filtering and separating to obtain a water extract filtrate, and repeatedly dissolving the ultrafinely pulverized brown algae in the water extract filtrate to obtain a saturated or supersaturated water extract filtrate; S2, adjusting the pH value of the saturated or supersaturated water filtrate to acidic, filtering and separating through a microfiltration membrane to obtain seaweed protein and a first filtrate; S3, adding calcium chloride to the first filtrate, allowing sedimentation to obtain alginate and a supernatant; S4. Filter the supernatant through a polyethersulfone (PES) composite membrane to remove free heavy metals and small molecular impurities to obtain a fucoidan concentrate.

[0028] S5. Spray-drying the fucoidan concentrate to obtain pure fucoidan powder.

[0029] In some embodiments, S1 specifically includes: ultrafinely grinding the brown algae, adding it to water, filtering and separating to remove the residue, obtaining a water extract filtrate, and repeatedly dissolving the next batch of ultrafinely ground brown algae in the water extract filtrate, and repeating this cycle until the water extract filtrate reaches a saturated or supersaturated state to obtain a saturated or supersaturated water extract filtrate.

[0030] In some embodiments, the water extraction filtrate is circulated at least 7 times to obtain the saturated or supersaturated water extraction filtrate, so as to reduce water usage by 80% (instead of adding new water each time extraction, the extract is added).

[0031] In some embodiments, in S2, an acid is used to adjust the pH value of the water filtrate to 1.8-4.5.

[0032] In some embodiments, the acid is selected from at least one of citric acid, hydrochloric acid, and acetic acid.

[0033] In some embodiments, the microfiltration membrane is selected from ceramic microfiltration membranes.

[0034] In some embodiments, the pore size of the ceramic microfiltration membrane is 0.5 micrometers, and the flow rate of the saturated or supersaturated water filtrate through the ceramic microfiltration membrane is 15-200 L / h.

[0035] In some embodiments, in S3, calcium chloride is added to the first filtrate, so that the content of calcium chloride in the first filtrate is 1.5-2%.

[0036] In some embodiments, in S3, after sedimentation, centrifugation is performed using a disc centrifuge at a speed of 13500-14500g (i.e., the speed reaches 13500-14500 times the gravity) to obtain alginate and a supernatant.

[0037] In some embodiments, S4 specifically includes: filtering the supernatant with a polyethersulfone (PES) composite membrane having a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h, and concentrating to obtain an algae polysaccharide concentrate.

[0038] In some embodiments, S5 specifically includes: centrifugal spray drying the fucoidan concentrate at a rotation speed of 25,000 rpm to obtain fucoidan powder.

[0039] In some embodiments, the brown algae is selected from at least one of Undaria pinnatifida, Laminaria japonica, Sargassum fusiformis, and Sargassum.

[0040] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer, the process of stepwise extraction of protein, algin and algae polysaccharide from algae of the present invention will be further described in detail below in combination with specific embodiments and drawings. Obviously, the specific embodiments described are only part of the embodiments in the present application, not all of them. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation to the present application and its applications. Based on the specific embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present application.

[0041] If no specific techniques or conditions are specified in the specific embodiments, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0042] Example 1 like Figure 1 As shown, a process for stepwise extraction of seaweed protein, alginate and fucoidan from undaria pinnatifida comprises the following steps: S1, ultrafinely crushing the kelp, then adding water to extract, filtering and separating to obtain a water extract filtrate, and repeating the water extract filtrate cycle 7 times to dissolve the ultrafinely crushed kelp to obtain a saturated or supersaturated water extract filtrate; S2, using citric acid to adjust the pH value of the saturated or supersaturated water extract filtrate to 3.5, and then filtering the saturated or supersaturated water extract filtrate after adjusting the pH through a ceramic microfiltration membrane with a pore size of 0.5 microns at a flow rate of 200 L / h to obtain seaweed protein and a first filtrate, and the seaweed protein is used to produce artificial meat; S3, adding calcium chloride to the first filtrate so that the content of calcium chloride in the first filtrate is 1.5%, and then after sedimentation, centrifuging with a disc centrifuge at a speed of 13500g to obtain alginate and a supernatant, wherein the alginate is used to produce food products; S4, filtering the supernatant with a polyethersulfone (PES) composite membrane with a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h to remove small molecular impurities and heavy metal ions, and concentrating to obtain an algae polysaccharide concentrate; S5. The fucoidan concentrate is centrifugally spray-dried at a rotation speed of 25,000 rpm to obtain fucoidan powder. The fucoidan can be used to create functional foods, health products, biopharmaceuticals, etc.

[0043] Example 2 like Figure 1 As shown, a process for stepwise extraction of seaweed protein, alginate and fucoidan from kelp comprises the following steps: S1, ultrafinely crushing the kelp, then adding water to extract, filtering and separating, obtaining a water extract filtrate, and repeating the water extract filtrate cycle 7 times to dissolve the ultrafinely crushed kelp to obtain a saturated or supersaturated water extract filtrate; S2, using citric acid to adjust the pH value of the saturated or supersaturated water extract filtrate to 3, and then filtering the saturated or supersaturated water extract filtrate after adjusting the pH through a ceramic microfiltration membrane with a pore size of 0.5 microns at a flow rate of 200 L / h to obtain seaweed protein and a first filtrate, and the seaweed protein is used to produce artificial meat; S3, adding calcium chloride to the first filtrate so that the content of calcium chloride in the first filtrate is 1.8%, and then after sedimentation, centrifuging with a disc centrifuge at a speed of 14000g to obtain alginate and a supernatant, wherein the alginate is used to produce food products; S4, filtering the supernatant with a polyethersulfone (PES) composite membrane with a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h to remove small molecular impurities and heavy metal ions, and concentrating to obtain an algae polysaccharide concentrate; S5. The fucoidan concentrate is centrifugally spray-dried at a rotation speed of 25,000 rpm to obtain fucoidan powder. The fucoidan can be used to create functional foods, health products, biopharmaceuticals, etc.

[0044] Example 3 like Figure 1 As shown, a process for stepwise extraction of seaweed protein, alginate and fucoidan from Sargassum fusiformis comprises the following steps: S1, ultrafinely pulverize the seaweed, then add water to extract, filter and separate, obtain a water extract filtrate, and repeat the water extract filtrate cycle 7 times to dissolve the ultrafinely pulverized kelp to obtain a saturated or supersaturated water extract filtrate; S2, using citric acid to adjust the pH value of the saturated or supersaturated water extract filtrate to 3.5, and then filtering the saturated or supersaturated water extract filtrate after adjusting the pH through a ceramic microfiltration membrane with a pore size of 0.5 microns at a flow rate of 200 L / h to obtain seaweed protein and a first filtrate, and the seaweed protein is used to produce artificial meat; S3, adding calcium chloride to the first filtrate so that the content of calcium chloride in the first filtrate is 2%, and then after sedimentation, centrifuging with a disc centrifuge at a speed of 14500g to obtain alginate and a supernatant, wherein the alginate is used to produce food products; S4, filtering the supernatant with a polyethersulfone (PES) composite membrane with a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h to remove small molecular impurities and heavy metal ions, and concentrating to obtain an algae polysaccharide concentrate; S5. The fucoidan concentrate is centrifugally spray-dried at a rotation speed of 25,000 rpm to obtain fucoidan powder. The fucoidan can be used to create functional foods, health products, biopharmaceuticals, etc.

[0045] Among them, seaweed protein accounts for 0.1-0.5% of the wet weight (1-5% of the dry weight) in seaweed (including undaria, kelp, and hijiki, etc.), and alginate accounts for 2-5% of the wet weight (undaria 2-3%, kelp 3-4%, hijiki 3-5%, dry weight x10). Fucoidan accounts for 0.5-1.5% of the wet weight (undaria 0.7-1.5%, kelp 0.5-0.8%, hijiki 0.6-1.2%, dry weight x10). The process of the present invention can obtain seaweed protein, alginate and fucoidan with high purity and low heavy metal pollution. According to research and determination, the purity of seaweed protein can reach 60%, the purity of alginate can reach 50%, and the purity of fucoidan can reach 85%. The maximum retention of biological activity is not less than 50%. At the same time, the cost is reduced by more than 50% compared with single extraction, the waste discharge is reduced by 90%, and the water consumption is reduced by 80%.

[0046] Specifically: (1) Water consumption is reduced by 80%: This process uses 7 cycles of supersaturated water extraction to reduce the water consumption in the extraction process to 1 / 7 of that in a single extraction. The step-by-step extraction method can use a set of processes to simultaneously obtain three raw materials, namely seaweed protein, alginate or algae polysaccharide, replacing three extractions of three raw materials, and the water consumption is 1 / 3 of that in a single process. In addition, this process avoids the alcohol precipitation process and also avoids the water used for washing and decolorization in the alcohol precipitation process. Comprehensive calculation shows that the water consumption can be reduced by 80% compared with a single extraction. (2) Waste discharge is reduced by 90%: The single extraction method only obtains a single component of seaweed protein, alginate or algae polysaccharide, which contains less than 5% of the total raw material, and 90-95% is waste and needs to be discharged and treated; in addition, a large amount of waste ethanol will be generated in the alcohol precipitation process. In this process, ultrafine grinding and cyclic supersaturated water extraction can obtain more than 90% of the seaweed protein, alginate or algae polysaccharide in the seaweed raw material in steps, and no ethanol treatment is used, only a small amount of waste residue and wastewater is generated. (3) Cost reduction of more than 50% compared with single extraction: This process uses a set of processes to obtain three raw materials, seaweed protein, algin or algae polysaccharide, and the cost of water, electricity and fuel is reduced to 20% of the cost of single extraction. The cost of ethanol raw materials and alcohol precipitation operation costs of the alcohol precipitation process are eliminated, and the cost of sewage treatment is reduced by 80%, and the cost of waste treatment is reduced by 90%. Comprehensive calculation, the cost reduction is more than 50%. (4) Maximum retention of biological activity of not less than 50%: This process has mild extraction conditions and maximizes the activity of the three components of seaweed protein, algin or algae polysaccharide. It has been confirmed by experiments that the biological activity is not less than 50%.

[0047] The process of the stepwise extraction of seaweed protein, alginate and fucoidan from brown algae of the present invention abandons the traditional water-soluble alcohol precipitation process, adopts the cyclic supersaturation and ultrafiltration membrane graded extraction technology, and extracts almost all the seaweed carbohydrates and proteins soluble in water in stages, producing more products without increasing or reducing costs, and eliminating the use of organic solvents. In the purification stage, the membrane concentration process is combined with the membrane concentration process to replace the traditional thermal concentration, improve the separation and concentration efficiency and retain the biological activity to the maximum extent of not less than 50%, which can greatly reduce the production cost, while retaining the nutritional value and flavor of the functional factors to the maximum extent, meet the large-scale comprehensive extraction needs, and contribute to the subsequent development of health foods and special medical foods. Compared with the traditional pure ethanol precipitation method, this technology has multiple advantages and innovations.

[0048] (1) New multi-component comprehensive extraction The process of the present invention can realize the stepwise extraction of seaweed functional components. Compared with the traditional single component extraction method, this technology can stepwise extract components such as fucoidan, alginate, and protein from seaweed, reduce waste generation, achieve high-value full utilization of valuable components of seaweed, and produce a variety of products, such as alginate can be used as food colloid, protein can be used to make artificial meat, and fucoidan can be used to create functional foods, health products, and biopharmaceuticals.

[0049] (2) Environmentally friendly The process of the present invention can significantly reduce the amount of water resources used and waste, and eliminate the use of organic solvents. Ultrafine grinding can make carbohydrates and proteins dissolve better, and the use of circulating water can promote the saturated dissolution of carbohydrates and proteins, which helps to reduce the amount of water resources used. The process coupling of extraction technology and ultrafiltration membrane technology can ensure that no chemical reagents are added during the protein extraction process, and eliminate the use of organic solvents. The entire extraction process only produces very little waste, which helps to reduce the waste of resources.

[0050] (3) Reducing costs and increasing efficiency The process of the present invention can significantly reduce the production and preparation costs. First, the traditional hydrolysis process requires the use of a large amount of pure ethanol to precipitate fucoidan. Although ethanol can be recycled, the overall cost of this method is high, resulting in high prices for brown algae polysaccharide products. This technology combines cyclic supersaturation and ultrafiltration technology to eliminate the need for ethanol in the production process. At the same time, the extraction technology is coupled with membrane separation, purification and concentration technology. Through step-by-step extraction, multi-component comprehensive extraction is achieved while achieving green and low-carbon production, thereby achieving high-value utilization of each component and reducing waste. While helping to protect the environment, it can reduce production costs by more than 50%.

[0051] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A process for stepwise extraction of algal protein, alginate and fucoidan from brown algae, characterized in that: The following steps are involved: S1, ultrafinely pulverizing the brown algae, then extracting with water, filtering and separating to obtain a water extract filtrate, and repeatedly dissolving the ultrafinely pulverized brown algae in the water extract filtrate to obtain a saturated or supersaturated water extract filtrate; S2, adjusting the pH value of the saturated or supersaturated water filtrate to acidic, filtering and separating through a microfiltration membrane to obtain seaweed protein and a first filtrate; S3, adding calcium chloride to the first filtrate, allowing sedimentation to obtain alginate and a supernatant; S4, filtering the supernatant through a polyethersulfone (PES) composite membrane to remove free heavy metals and small molecular impurities to obtain a fucoidan concentrate; S5. Spray-drying the fucoidan concentrated solution to obtain fucoidan powder.

2. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: The step S1 specifically includes: ultrafinely grinding the brown algae, adding the brown algae to water, filtering and separating the brown algae to obtain a water extract filtrate, and repeatedly dissolving the next batch of ultrafinely ground brown algae in the water extract filtrate, and repeating the cycle to make the water extract filtrate reach a saturated or supersaturated state to obtain a saturated or supersaturated water extract filtrate.

3. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 2, characterized in that: The water extraction filtrate is circulated at least 7 times to obtain the saturated or supersaturated water extraction filtrate.

4. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: In S2, the pH value of the saturated or supersaturated water filtrate is adjusted to 1.8-4.5 by using an acid; The acid is selected from at least one of citric acid, hydrochloric acid and acetic acid.

5. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: The microfiltration membrane is selected from ceramic microfiltration membrane.

6. The process for stepwise extraction of algal protein, alginate and fucoidan from brown algae according to claim 5, characterized in that: The pore size of the ceramic microfiltration membrane is 0.5 micrometers, and the flow rate of the saturated or supersaturated water filtrate through the ceramic microfiltration membrane is 200 L / h.

7. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: In S3, calcium chloride is added to the first filtrate, so that the content of calcium chloride in the first filtrate is 1.5-2%.

8. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: In S3, after sedimentation, a disc centrifuge is used for centrifugal separation at a rotation speed of 13500-14500g to obtain alginate and a supernatant.

9. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: The S4 specifically includes: filtering the supernatant with a polyethersulfone (PES) composite membrane having a pore size of 500-1000 Dalton at a flow rate of 15-20 L / h, and concentrating to obtain a fucoidan concentrate.

10. The process for stepwise extraction of algae protein, alginate and fucoidan from brown algae according to claim 1, characterized in that: The S5 specifically includes: centrifugation spray drying the fucoidan concentrate at a rotation speed of 25,000 rpm to obtain fucoidan powder; And / or, the brown algae is selected from at least one of Undaria pinnatifida, Laminaria japonica, Sargassum fusiformis and Sargassum.

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