Preparation method of beta-carotene based on dunaliella salina
By using combined physical wall-breaking technology and supercritical CO2 extraction technology in Dunaliella salina, the problems of low efficiency and poor product quality of existing microalgae lipid extraction methods have been solved, and efficient, green β-carotene extraction has been achieved. , improving the purity and stability of the product.
Patent Information
- Application Number
- CN202411441653.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-01-24
AI Technical Summary
The existing microalgae lipid extraction methods have problems such as low separation efficiency, time-consuming, poor product quality, low purity and harmful odor, which are difficult to meet the needs of industrialization.
Using a β-carotene preparation method based on Dunaliella salina, the algae cell wall is destroyed by combining physical wall-breaking technology and supercritical CO2 extraction technology to improve the extraction rate and product purity.
The extraction rate and purity of β-carotene have been improved, and the green and efficient extraction and separation techniques are achieved. The products have the advantages of high purity, maintaining biological activity, high extraction rate, pure color taste, and strong stability.
Smart Images
Figure CN119350207A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of carotene preparation, and in particular to a method for preparing beta-carotene based on Dunaliella salina. Background Art
[0002] Since the 1960s, foreign countries have invested heavily in the exploration and research of marine natural active substances and marine drugs, but the research objects are mostly marine animals such as sponges, echinoderms, mollusks, coelenterates and fish, and large algae, and have not paid much attention to individual tiny marine microalgae; however, recent studies have found that microalgae are not only rich in resources, but also have a wide variety of active substances; there is a surge in the international trend of screening and extracting new drugs and health products from microalgae, especially anti-aging active substances such as pigments and fatty acids. Domestic research in this area has just started. my country has recorded more than 4,000 species of marine microalgae, but the species that have been studied are conservatively estimated to account for less than 2%, so there is huge potential for development.
[0003] Research in recent years has found that microalgae are not only rich in resources, but also have a wide variety of active substances. There is a surge in the international community to screen and extract new drugs from microalgae, especially anti-aging active substances such as pigments and fatty acids. Domestic research in this area has just started. Therefore, the application of microbial technology to screen, extract and produce algae anti-aging active substances has attracted widespread attention and has huge market development potential. In the process of developing marine biological active substances with market potential, solving the problem of industrialization is the most critical issue.
[0004] At present, the main methods for extracting microalgae lipids include organic solvent method, two-phase extraction method, Soxhlet extraction method, acid-heat method and supercritical CO2 extraction method. The separation efficiency of organic solvent extraction is low, it is time-consuming, the product quality is poor, the purity is low, there is odor, and the organic solvent is volatile and harmful to the human body; the Soxhlet method has the highest extraction rate, but it is time-consuming and can only measure crude fat; the acid-heat method is not suitable for the extraction of substances with high sugar content, because sugars are easily carbonized when exposed to strong acids, which affects the measurement results.
[0005] To this end, we proposed a method for preparing β-carotene based on Dunaliella salina. Summary of the invention
[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for preparing β-carotene based on Dunaliella salina, which solves the technical problems raised in the above-mentioned background technology.
[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for preparing beta-carotene based on Dunaliella salina comprises the following steps: Step 1: Collect the algae liquid and perform centrifugal dehydration on the algae liquid to obtain algae mud; Step 2: The obtained algae mud is further subjected to a wall-breaking treatment to provide conditions for the preparation of β-carotene; Step 3: receiving the algae mud after the cell wall is broken, and further drying it to obtain algae powder, thereby providing conditions for the preparation of β-carotene; Step 4: Place the dried algae powder into a supercritical In the extraction kettle of the extraction equipment, set the supercritical The extraction conditions are as follows: temperature is 40-60℃, pressure is 20-30MPa; the extracted β-carotene- The mixture flows into the separation kettle and the pressure is reduced or the temperature is increased. Transform into gaseous state and escape to obtain an extract rich in β-carotene; Step 5: weigh a quantitative amount of the extract, dissolve it in an organic solvent, and prepare at least three standard solutions of different concentrations. Inject the standard solutions into a high performance liquid chromatograph, use a C18 chromatographic column with methanol-acetonitrile as the mobile phase, a flow rate of 1.0-1.5 ml / min, and a detection wavelength of 450 nm, draw a peak area-concentration standard curve of β-carotene, and calculate the content of β-carotene in the extract by comparing with the standard curve; Step 6: purify the extract by column chromatography and store the β-carotene at -20°C in a dry environment away from light.
[0008] Furthermore, the culture conditions of the Dunaliella salina include: salinity of 15% - 25% NaCl solution, temperature of 25 - 30°C, light intensity of 3000 - 5000 lux, and light-dark cycle of 12h:12h; The algae liquid for preparing β-carotene is collected at the late logarithmic phase and early stable phase of the growth of Dunaliella salina.
[0009] Furthermore, when the algae liquid is subjected to centrifugal dehydration, the algae liquid is placed in a centrifuge, the speed of the centrifuge is set to 3000-5000 r / mi, and the centrifugal dehydration time is continued to be 10-20 minutes.
[0010] Furthermore, the algae mud is subjected to a wall-breaking treatment by using either a high-pressure homogenization method or an enzymatic hydrolysis method; The operating steps of the high-pressure homogenization method are as follows: placing the algae mud in a high-pressure homogenizer and homogenizing it at a pressure of 80-120 MPa to rupture the cell walls of the algae cells and release the β-carotene in the cells; The enzymatic hydrolysis method comprises the following steps: adding cell wall degrading enzyme to the algae mud, reacting for 1 to 3 hours at a temperature of 30 to 40 degrees Celsius and a pH value of 4.5 to 6.5 to destroy the cell wall structure and release the beta-carotene in the cell.
[0011] Furthermore, in the enzymatic hydrolysis method, the cell wall degrading enzyme added to the algae mud is any one of cellulase and pectinase.
[0012] Furthermore, when the algae mud after the cell wall is further dried, any one of low-temperature vacuum drying and low-temperature spray drying is used for drying; The low-temperature vacuum drying operation steps are as follows: evenly spread the broken algae mud on a drying plate with a thickness of 1-2 cm, put it into a low-temperature vacuum drying oven, set the drying temperature to 30-40° C., the vacuum degree to 0.08-0.1 MPa, and the drying time to 12-24 hours, until the algae mud is completely dried to form dry algae powder; The operation steps of the low-temperature spray drying are: making the broken algae mud into a uniform algae liquid, drying it through a spray dryer, setting the inlet temperature of the spray dryer to 150-180°C and the outlet temperature to 70-90°C to obtain dry algae powder.
[0013] Furthermore, the algae mud after wall breaking is made into uniform algae liquid, which is mixed with distilled water, and the mass ratio of distilled water to algae mud is less than 1:1. 0.5% of maltodextrin of the total mass of the algae liquid is added to the prepared algae liquid as a drying aid.
[0014] Furthermore, the operation time of the extraction kettle is 1 to 3 hours.
[0015] Furthermore, the organic solvent for dissolving the extract is any one of n-hexane, petroleum ether, dichloromethane, acetone or ethyl acetate.
[0016] Furthermore, the composition ratio of methanol to acetonitrile is 90:10.
[0017] Compared with the known public technology, the technical solution provided by the present invention has the following beneficial effects: The present invention provides a method for preparing β-carotene based on Dunaliella salina. During the execution of the method, a combined physical wall breaking technology is used to break the wall of Dunaliella salina, and then supercritical CO2 is used to extract β-carotene to improve the extraction rate. Supercritical CO2 is a green separation technology. The physiologically active substances extracted from microalgae have the advantages of high purity, maintaining biological activity, high extraction rate, pure color and taste, strong stability, and high product added value. It has become a green, high-tech extraction and separation technology with huge development potential. This project uses patented technology and salt irrigation physical wall breaking followed by CO2 extraction to greatly improve the extraction rate, which is an innovative process. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 The figure is a schematic diagram of the technical route for a method for preparing β-carotene based on Dunaliella salina. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] The present invention will be further described below in conjunction with the embodiments.
[0022] Embodiment 1: A method for preparing β-carotene based on Dunaliella salina in this embodiment comprises the following steps: Step 1: Collect the algae liquid and perform centrifugal dehydration on the algae liquid to obtain algae mud; Step 2: The obtained algae mud is further subjected to a wall-breaking treatment to provide conditions for the preparation of β-carotene; Step 3: receiving the algae mud after the cell wall is broken, and further drying it to obtain algae powder, thereby providing conditions for the preparation of β-carotene; Step 4: Place the dried algae powder into a supercritical In the extraction kettle of the extraction equipment, set the supercritical The extraction conditions are as follows: temperature is 40-60℃, pressure is 20-30MPa; the extracted β-carotene- The mixture flows into the separation kettle and the pressure is reduced or the temperature is increased. Transform into gaseous state and escape to obtain an extract rich in β-carotene; Step 5: weigh a quantitative amount of the extract, dissolve it in an organic solvent, and prepare at least three standard solutions of different concentrations. Inject the standard solutions into a high performance liquid chromatograph, use a C18 chromatographic column with methanol-acetonitrile as the mobile phase, a flow rate of 1.0-.5 ml / min, and a detection wavelength of 450 nm, draw a peak area-concentration standard curve of β-carotene, and calculate the content of β-carotene in the extract by comparing with the standard curve; Step 6: purify the extract by column chromatography and store the β-carotene at -20°C in a dry environment away from light.
[0023] The culture conditions of the Dunaliella salina include: a salinity of 15% - 25% NaCl solution, a temperature of 25 - 30°C, a light intensity of 3000 - 5000 lux, and a light-dark cycle of 12h:12h; The algae solution for preparing β-carotene is collected at the late logarithmic phase and early stable phase of Dunaliella salina growth; When the algae liquid is subjected to centrifugal dehydration treatment, the algae liquid is placed in a centrifuge, the centrifuge speed is set to 3000-5000 r / mi, and the centrifugal dehydration time is continued to be 10-20 minutes; The algae mud is subjected to a high-pressure homogenization method or an enzymatic hydrolysis method when the algae mud is subjected to a wall-breaking treatment; The operating steps of the high-pressure homogenization method are as follows: placing the algae mud in a high-pressure homogenizer and homogenizing it at a pressure of 80-120 MPa to rupture the cell walls of the algae cells and release the β-carotene in the cells; The enzymatic hydrolysis method comprises the following steps: adding a cell wall degrading enzyme to the algae mud, reacting for 1 to 3 hours at a temperature of 30 to 40 degrees Celsius and a pH value of 4.5 to 6.5 to destroy the cell wall structure and release the β-carotene in the cell; In the enzymatic hydrolysis method, the cell wall degrading enzyme added to the algae mud is any one of cellulase and pectinase; When the algae mud after the cell wall is further dried, any one of low-temperature vacuum drying and low-temperature spray drying is used for drying; The low-temperature vacuum drying operation steps are as follows: evenly spread the broken algae mud on a drying plate with a thickness of 1-2 cm, put it into a low-temperature vacuum drying oven, set the drying temperature to 30-40° C., the vacuum degree to 0.08-0.1 MPa, and the drying time to 12-24 hours, until the algae mud is completely dried to form dry algae powder; The low-temperature spray drying operation steps are as follows: the algae mud after the wall breaking is made into a uniform algae liquid, and dried by a spray dryer, the inlet temperature of the spray dryer is set to 150-180°C, and the outlet temperature is set to 70-90°C, to obtain dry algae powder; The algae mud after cell wall breaking is made into a uniform algae liquid, and distilled water is used to mix the algae mud, and the mixing mass ratio of distilled water to algae mud is less than 1:1, and 0.5% of the total mass of the algae liquid is added to the prepared algae liquid as a drying aid. The operation time of the extraction kettle is 1 to 3 hours; The organic solvent for dissolving the extract is any one of n-hexane, petroleum ether, dichloromethane, acetone or ethyl acetate; The composition ratio of methanol to acetonitrile is 90:10.
[0024] Embodiment 2: A method for preparing beta-carotene based on Dunaliella salina comprises the following steps: Step 1: Collect the algae liquid and perform centrifugal dehydration on the algae liquid to obtain algae mud; Step 2: The obtained algae mud is further subjected to a wall-breaking treatment to provide conditions for the preparation of β-carotene; Step 3: receiving the algae mud after the cell wall is broken, and further drying it to obtain algae powder, thereby providing conditions for the preparation of β-carotene; Step 4: Place the dried algae powder into a supercritical In the extraction kettle of the extraction equipment, set the supercritical The extraction conditions are as follows: temperature is 60℃, pressure is 30MPa; the extracted β-carotene- The mixture flows into the separation kettle and the pressure is reduced or the temperature is increased. Transform into gaseous state and escape to obtain an extract rich in β-carotene; Step 5: weigh a quantitative amount of the extract, dissolve it in an organic solvent, and prepare at least three standard solutions of different concentrations. Inject the standard solutions into a high performance liquid chromatograph, use a C18 chromatographic column with methanol-acetonitrile as the mobile phase, a flow rate of 1.5 ml / min, and a detection wavelength of 450 nm, draw a peak area-concentration standard curve of β-carotene, and calculate the content of β-carotene in the extract by comparing with the standard curve; Step 6: purify the extract by column chromatography and store the β-carotene at -20°C in a dry environment away from light.
[0025] The culture conditions of the Dunaliella salina include: salinity of 25% NaCl solution, temperature of 30°C, light intensity of 5000 lux, and light-dark cycle of 12h:12h; The algae solution for preparing β-carotene is collected at the late logarithmic phase and early stable phase of Dunaliella salina growth; When the algae liquid is subjected to centrifugal dehydration treatment, the algae liquid is placed in a centrifuge, the centrifuge speed is set to 5000 r / mi, and the centrifugal dehydration time is continued for 20 minutes; The algae mud is subjected to a high-pressure homogenization method or an enzymatic hydrolysis method when the algae mud is subjected to a wall-breaking treatment; The operating steps of the high-pressure homogenization method are as follows: placing algae mud in a high-pressure homogenizer and homogenizing it at a pressure of 120 MPa to rupture the cell walls of algae cells and release the β-carotene in the cells; The enzymatic hydrolysis method comprises the following steps: adding cell wall degrading enzyme to the algae mud, reacting for 3 hours at a temperature of 30 to 40 degrees Celsius and a pH value of 6.5 to destroy the cell wall structure and release the β-carotene in the cell; In the enzymatic hydrolysis method, the cell wall degrading enzyme added to the algae mud is any one of cellulase and pectinase; When the algae mud after the cell wall is further dried, any one of low-temperature vacuum drying and low-temperature spray drying is used for drying; The low-temperature vacuum drying operation steps are as follows: the algae mud after wall breaking is evenly spread on a drying plate with a thickness of 2 cm, and placed in a low-temperature vacuum drying oven, and the drying temperature is set to 40° C., the vacuum degree is 0.1 MPa, and the drying time is 24 hours, until the algae mud is completely dried to form dry algae powder; The low-temperature spray drying operation steps are as follows: the algae mud after the wall breaking is made into a uniform algae liquid, and dried by a spray dryer, and the inlet temperature of the spray dryer is set to 180° C. and the outlet temperature is set to 90° C. to obtain dry algae powder; The algae mud after cell wall breaking is made into a uniform algae liquid, and distilled water is used to mix the algae mud, and the mixing mass ratio of distilled water to algae mud is less than 1:1, and 0.5% of the total mass of the algae liquid is added to the prepared algae liquid as a drying aid. The running time of the extraction kettle is 3 hours; The organic solvent for dissolving the extract is any one of n-hexane, petroleum ether, dichloromethane, acetone or ethyl acetate; The composition ratio of methanol to acetonitrile is 90:10.
[0026] Embodiment 3: A method for preparing beta-carotene based on Dunaliella salina comprises the following steps: Step 1: Collect the algae liquid and perform centrifugal dehydration on the algae liquid to obtain algae mud; Step 2: The obtained algae mud is further subjected to a wall-breaking treatment to provide conditions for the preparation of β-carotene; Step 3: receiving the algae mud after the cell wall is broken, and further drying it to obtain algae powder, thereby providing conditions for the preparation of β-carotene; Step 4: Place the dried algae powder into a supercritical In the extraction kettle of the extraction equipment, set the supercritical The extraction conditions are as follows: temperature is 40℃, pressure is 20MPa; the extracted β-carotene- The mixture flows into the separation kettle and the pressure is reduced or the temperature is increased. Transform into gaseous state and escape to obtain an extract rich in β-carotene; Step 5: weigh a quantitative amount of the extract, dissolve it in an organic solvent, and prepare at least three standard solutions of different concentrations. Inject the standard solutions into a high performance liquid chromatograph, use a C18 chromatographic column with methanol-acetonitrile as the mobile phase, a flow rate of 1.0 ml / min, and a detection wavelength of 450 nm, draw a peak area-concentration standard curve of β-carotene, and calculate the content of β-carotene in the extract by comparing with the standard curve; Step 6: purify the extract by column chromatography and store the β-carotene at -20°C in a dry environment away from light.
[0027] The culture conditions of the Dunaliella salina include: salinity of 15% NaCl solution, temperature of 25° C., light intensity of 3000 lux, and light-dark cycle of 12h:12h; The algae solution for preparing β-carotene is collected at the late logarithmic phase and early stable phase of Dunaliella salina growth; When the algae liquid is subjected to centrifugal dehydration treatment, the algae liquid is placed in a centrifuge, the centrifuge speed is set to 3000 r / mi, and the centrifugal dehydration time is continued for 10 minutes; The algae mud is subjected to a high-pressure homogenization method or an enzymatic hydrolysis method when the algae mud is subjected to a wall-breaking treatment; The operating steps of the high-pressure homogenization method are as follows: placing algae mud in a high-pressure homogenizer and homogenizing it at a pressure of 80 MPa to rupture the cell walls of algae cells and release the β-carotene in the cells; The enzymatic hydrolysis method comprises the following steps: adding cell wall degrading enzyme to the algae mud, reacting for 1 hour at a temperature of 30 degrees Celsius and a pH value of 4.5 to destroy the cell wall structure and release the β-carotene in the cell; In the enzymatic hydrolysis method, the cell wall degrading enzyme added to the algae mud is any one of cellulase and pectinase; When the algae mud after the cell wall is further dried, any one of low-temperature vacuum drying and low-temperature spray drying is used for drying; The low-temperature vacuum drying operation steps are as follows: the algae mud after wall breaking is evenly spread on a drying plate with a thickness of 1 cm, and placed in a low-temperature vacuum drying oven, and the drying temperature is set to 30° C., the vacuum degree is 0.08 MPa, and the drying time is 12 hours, until the algae mud is completely dried to form dry algae powder; The low-temperature spray drying operation steps are as follows: the algae mud after the wall breaking is made into a uniform algae liquid, and dried by a spray dryer, and the inlet temperature of the spray dryer is set to 150° C. and the outlet temperature is set to 70° C. to obtain dry algae powder; The algae mud after cell wall breaking is made into a uniform algae liquid, and distilled water is used to mix the algae mud, and the mixing mass ratio of distilled water to algae mud is less than 1:1, and 0.5% of the total mass of the algae liquid is added to the prepared algae liquid as a drying aid. The running time of the extraction kettle is 2 hours; The organic solvent for dissolving the extract is any one of n-hexane, petroleum ether, dichloromethane, acetone or ethyl acetate; The composition ratio of methanol to acetonitrile is 90:10.
[0028] In summary, the method in the above embodiment uses a combined physical wall breaking technology to break the salt algae during execution, and then uses supercritical CO2 to extract β-carrot to improve the extraction rate. Supercritical CO2, as a green separation technology, extracts physiologically active substances from microalgae with high purity, maintains biological activity, high extraction rate, pure color and taste, strong stability, and high product added value. It has become a green, high-tech extraction and separation technology with huge development potential. This project uses patented technology and salt irrigation physical wall breaking followed by CO2 extraction to greatly improve the extraction rate, which is an innovative process.
[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing β-carotene based on Dunaliella salina, characterized in that: The following steps are involved: Step 1: Collect the algae liquid and perform centrifugal dehydration on the algae liquid to obtain algae mud; Step 2: The obtained algae mud is further subjected to a wall-breaking treatment to provide conditions for the preparation of β-carotene; Step 3: receiving the algae mud after the cell wall is broken, and further drying it to obtain algae powder, thereby providing conditions for the preparation of β-carotene; Step 4: Place the dried algae powder into a supercritical In the extraction kettle of the extraction equipment, set the supercritical The extraction conditions are as follows: temperature is 40-60℃, pressure is 20-30MPa; the extracted β-carotene- The mixture flows into the separation kettle and the pressure is reduced or the temperature is increased. Transform into gaseous state and escape to obtain an extract rich in β-carotene; Step 5: weigh a quantitative amount of the extract, dissolve it in an organic solvent, and prepare at least three standard solutions of different concentrations. Inject the standard solutions into a high performance liquid chromatograph, use a C18 chromatographic column with methanol-acetonitrile as the mobile phase, a flow rate of 1.0-1.5 ml / min, and a detection wavelength of 450 nm, draw a peak area-concentration standard curve of β-carotene, and calculate the content of β-carotene in the extract by comparing with the standard curve; Step 6: purify the extract by column chromatography and store the β-carotene at -20°C in a dry environment away from light.
2. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: The culture conditions of the Dunaliella salina include: a salinity of 15% - 25% NaCl solution, a temperature of 25 - 30°C, a light intensity of 3000 - 5000 lux, and a light-dark cycle of 12h:12h; The algae liquid for preparing β-carotene is collected at the late logarithmic phase and early stable phase of the growth of Dunaliella salina.
3. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: When the algae liquid is subjected to centrifugal dehydration treatment, the algae liquid is placed in a centrifuge, the speed of the centrifuge is set to 3000-5000 r / mi, and the centrifugal dehydration time is continued to be 10-20 minutes.
4. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: The algae mud is subjected to a high-pressure homogenization method or an enzymatic hydrolysis method when the algae mud is subjected to a wall-breaking treatment; The operating steps of the high-pressure homogenization method are as follows: placing the algae mud in a high-pressure homogenizer and homogenizing it at a pressure of 80-120 MPa to rupture the cell walls of the algae cells and release the β-carotene in the cells; The enzymatic hydrolysis method comprises the following steps: adding cell wall degrading enzyme to the algae mud, reacting for 1 to 3 hours at a temperature of 30 to 40 degrees Celsius and a pH value of 4.5 to 6.5 to destroy the cell wall structure and release the beta-carotene in the cell.
5. The method for preparing β-carotene based on Dunaliella salina according to claim 4, characterized in that: In the enzymatic hydrolysis method, the cell wall degrading enzyme added to the algae mud is any one of cellulase and pectinase.
6. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: When the algae mud after the cell wall is further dried, any one of low-temperature vacuum drying and low-temperature spray drying is used for drying; The low-temperature vacuum drying operation steps are as follows: evenly spread the broken algae mud on a drying plate with a thickness of 1-2 cm, put it into a low-temperature vacuum drying oven, set the drying temperature to 30-40° C., the vacuum degree to 0.08-0.1 MPa, and the drying time to 12-24 hours, until the algae mud is completely dried to form dry algae powder; The operation steps of the low-temperature spray drying are: making the broken algae mud into a uniform algae liquid, drying it through a spray dryer, setting the inlet temperature of the spray dryer to 150-180°C and the outlet temperature to 70-90°C to obtain dry algae powder.
7. The method for preparing β-carotene based on Dunaliella salina according to claim 6, characterized in that: The algae mud after wall breaking is made into uniform algae liquid, and distilled water is used to mix with the algae mud. The mass ratio of distilled water to algae mud is less than 1:
1. Maltodextrin is added into the algae liquid as a drying aid at a concentration of 0.5% of the total mass of the algae liquid.
8. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: The operation time of the extraction kettle is 1 to 3 hours.
9. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: The organic solvent for dissolving the extract is any one of n-hexane, petroleum ether, dichloromethane, acetone or ethyl acetate.
10. The method for preparing β-carotene based on Dunaliella salina according to claim 1, characterized in that: The composition ratio of methanol to acetonitrile is 90:10.