CN110590628A - Method for extracting natural astaxanthin from fresh shrimps and/or crab waste - Google Patents

Abstract

The invention relates to the technical field of biological treatment of shrimp and crab wastes, in particular to a method for preparing high-natural-astaxanthin-content dry shell powder from fresh shrimp and/or crab wastes. The method comprises the following steps: 1) crushing and pulping the waste of the fresh shrimps and/or the crabs to prepare fresh pulp; 2) pumping fresh slurry into an enzymolysis reaction kettle equipped with an ultrasonic device for enzymolysis by adopting a mixed enzyme preparation, wherein a food-grade antioxidant is added into the mixed enzyme preparation, and the adding amount of the food-grade antioxidant is 100-5000 ppm; 3) after enzymolysis, high-speed centrifugation is carried out, centrifugal slag is washed by deionized water, and acid water is added for decalcification; 4) and after decalcification and hardening, high-speed centrifugation is carried out, and centrifugal slag is dried in vacuum at 30-60 ℃ to obtain dry shell powder containing natural astaxanthin. The method is simple, adopts fresh shrimp and/or crab waste, can be treated on site, can remove residue thoroughly by enzymolysis of mixed protease and ultrasonic wave assistance, and adds food-grade antioxidant during enzymolysis process to protect oxidation of natural astaxanthin and improve natural astaxanthin content in product.

Description

Method for extracting natural astaxanthin from fresh shrimps and/or crab waste

Technical Field

The invention relates to the technical field of biological treatment of shrimp and crab wastes, in particular to a method for extracting natural astaxanthin from fresh shrimp and/or crab wastes.

Background

With the rapid increase of aquaculture and processing enterprises, the leftovers generated in the processing process are more and more, and are also serious pollution sources; take Zhejiang as an example; when manufacturing enterprises taking seawater shrimps or freshwater shrimps and crayfish as main raw materials process the leftovers, one part of the leftovers are sold as waste materials, the leftovers are hundreds of yuan per ton, or the leftovers are conveyed to a farm to be dried and crushed to be used as feed, and a plurality of leftovers which are not processed in time are piled up to be mildewed and rotten, so that the environment is seriously polluted, and finally the leftovers are directly conveyed to a garbage yard. The byproducts contain rich nutrients such as protein, astaxanthin and unsaturated fatty acid, and mineral salts such as calcium, magnesium and phosphorus, and nutrient components such as cephalin, lecithin, carotenoid, carbohydrate, cellulose and vitamin, and the shrimp byproducts mainly refer to leftovers (shrimp heads and rejected shrimps) of products such as shrimp meat and shrimp tails obtained by screening and processing raw material shrimps, and the leftovers contain a lot of residual meat. At present, many reports have been made on mixing a small amount of crushed shrimp heads, shrimp shells, etc. with fish meal as feed and bait, and extracting functional nutrients from the shrimp heads and the shrimp shells. A great amount of shrimp meat, shrimp brain and shrimp yellow are remained on the heads and the feet of the crayfish, the residues have higher utilization value, and the shrimp heads of the shrimp shells after meat collection can be further processed into biological protein calcium powder, astaxanthin, chitin, chitosan and the like.

At present, a large amount of crustacean waste of shrimp and crab processing industry is generated at home and abroad every year, and the extraction and recovery of astaxanthin from crustacean waste become one of the main ways for producing natural astaxanthin.

Astaxanthin is mainly present in the shells of crustaceans (such as shrimps and crabs) in 3 forms: (1) a protein-bound form; (2) in the form of an esterification; (3) in free form.

The free state is the least stable, the esterified form exists the most, and the astaxanthin in the esterified form is mainly effectively separated and purified in the actual extraction process. In recent years, inorganic acid or organic acid is added in the treatment process of countries such as Norway, the combination of astaxanthin and protein or skeleton parts is destroyed, the release amount of astaxanthin is increased, the recovery rate can reach 180 mug/g, the purity is greatly improved, but the market demand cannot be met.

Natural extract from crayfish headThe content of astaxanthin and fresh crayfish head is 25-30 mug/g, the traditional process adopts integral drying and then crushing, the oxidation loss of the astaxanthin reaches 15-20 percent due to the drying and crushing temperature, no matter the alkali extraction method, the organic solvent method and the supercritical CO method₂Extracting with adjuvant (alkali, oil, organic solvent, CO)₂) And the energy consumption is 3 times of that of the method; as the crayfish is a seasonal product (4-9 months), the oxidation loss of the natural astaxanthin reaches 30-40 percent in the conventional storage and transportation.

The invention patent (publication number: CN1715255A, published: 2006.01.04) applied by the applicant discloses a method for producing chitin, astaxanthin, protein, calcium powder and biological fertilizer by using shrimp shells, which comprises the following steps: crushing shrimp shells, adding a complex enzyme for enzymolysis, adding an organic solvent for extraction, separating into a shrimp liquid and a shrimp solid after full reaction, separating the shrimp liquid into a hydrolysate and an organic liquid, and performing vacuum concentration on the organic liquid containing astaxanthin to extract crude astaxanthin.

The Chinese invention patent application (publication No. CN108559765A, published: 2017, 12 and 28) discloses a method for extracting N-acetylglucosamine and astaxanthin from crayfish shells by a biological enzyme method. The method comprises the following steps: pretreating the crayfish shell to obtain crayfish shell powder; taking chitinase-producing microorganisms as test bacteria, inoculating the test bacteria to a seed culture medium for culture to obtain a seed solution, transferring the seed solution to a fermentation culture medium for fermentation, and purifying to obtain a crude pure enzyme solution; putting the crayfish shell powder into a reaction kettle, sequentially adding the crude pure enzyme solution and the organic reagent, stirring while keeping out of the sun, and heating to 20-37 ℃ at constant temperature to obtain an enzymatic hydrolysate; standing and layering the enzymolysis liquid, pouring out the upper layer liquid, and recovering the organic reagent and the shrimp sauce rich in astaxanthin under dark.

The method adopts the shrimp shell powder for enzymolysis and then adopts an organic reagent for extraction to obtain the astaxanthin, but the process steps are relatively complicated, and the oxidation loss of the astaxanthin is relatively large in the process. In addition, the complex process conditions are not beneficial to the on-site treatment of the raw materials, so that the centralized transportation and centralized treatment are needed; this in turn often leads to astaxanthin oxidation losses during transport and intensive handling and also to costs for inventory and logistics and environmental pollution from waste products during production.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a method for extracting natural astaxanthin from fresh shrimp and/or crab wastes, which is simple and convenient, adopts the fresh shrimp and/or crab wastes, can be treated on site, can remove residues more thoroughly through mixed protease enzymolysis and ultrasonic wave assistance, and adds a food-grade antioxidant in the enzymolysis process, thereby protecting the oxidation of natural astaxanthin and improving the content of natural astaxanthin in products.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for extracting natural astaxanthin from fresh shrimp and/or crab waste, comprising the steps of:

1) crushing and pulping the waste of the fresh shrimps and/or the crabs to prepare fresh pulp;

2) pumping fresh slurry into an enzymolysis reaction kettle equipped with an ultrasonic device for enzymolysis by adopting a mixed enzyme preparation, wherein a food-grade antioxidant is added into the mixed enzyme preparation, and the adding amount of the food-grade antioxidant is 100-5000 ppm;

3) after enzymolysis, high-speed centrifugation is carried out, centrifugal slag is washed by deionized water, and acid water is added for decalcification;

4) and after decalcification and hardening, high-speed centrifugation is carried out, and centrifugal slag is dried in vacuum at 30-60 ℃ to obtain dry shell powder containing natural astaxanthin.

Preferably, the animal source of fresh shrimp and/or crab waste comprises one or more of sea shrimp, freshwater shrimp, crayfish and crab; the waste is in the form of one or more of shrimp head, rejected shrimp, shrimp leg, shrimp shell, crab leg, crab shell and rejected crab. Most preferred herein are crawfish heads and crawfish tails.

Preferably, the power of the ultrasonic device: 50W-250W, frequency: 15kHz-50 kHz; the fresh slurry is 5-10 mesh in sheet shape, and has water content of 50-55%.

Preferably, the solid-liquid ratio of enzymolysis is 1: 1.5 ~ 1:5, the pH is adjusted to be 7.0-8.0, the enzyme dosage is 5000-10000U/g, and the enzymolysis is carried out for 4.0-6.0h at 50-60 ℃.

Preferably, the mixed enzyme preparation comprises papain, trypsin and lipase, wherein the papain, the trypsin and the lipase are mixed according to the proportion of U/g: 1-2: 0.2-0.5: 0.1-0.3.

Preferably, the acid water is decalcified and added with acid water, and simultaneously added with food-grade antioxidant 100-2000ppm, and the acid water adopts low-concentration HCl or organic acid.

Preferably, the food grade antioxidant is one or more of vitamin E, vitamin C, L-sodium ascorbate, BHA, PG and BHT.

As a further improvement, after the high-speed centrifugation in the step 3), the centrifugate is transferred to a protein extraction process, and the protein extraction process comprises the following steps:

1.1) stirring the enzymolysis centrifugate at 100 ℃ for 0.5h, controlling the temperature at 60 ℃, adding 5% (w: v) of chitosan-cellulose-activated carbon composite adsorption resin, stirring for 1h, and decoloring, deodorizing, removing heavy metal ions, residual and harmful substances;

1.2) microfiltration is carried out to remove particle impurities while the solution is hot;

1.3) concentrating in vacuum to obtain concentrated protein powder with solid content not less than 10%.

As a further improvement, after high-speed centrifugation in the step 4), adding K2CO3 into the hydrochloric acid-containing centrifugate to adjust Ph6-6.5, introducing CO2 to generate white precipitate, carrying out high-speed filtration and centrifugation, carrying out vacuum drying on the centrifugal slag, controlling the temperature to be less than or equal to 80 ℃, and controlling the moisture to be less than or equal to 10% to obtain finished bioactive calcium, and transferring the centrifugate into liquid fertilizer water;

or, after high-speed centrifugation in the step 4), microfiltration is carried out on the centrifugate containing the organic acid to remove particle impurities, the solid content is more than or equal to 10 percent through vacuum concentration, and the organic bioactive calcium powder is prepared through spray drying.

As a further improvement, the method also comprises the preparation steps of the chitosan oligosaccharide liquid organic fertilizer:

A. mixing the cleaning water for cleaning the shrimp heads and the residues with the cleaning water of the reaction kettle; adding chitosan flocculant for precipitation, taking supernatant, passing through anion and cation resins, and recycling as cleaning water;

B. mixing the flocculation solution and the bioactive calcium centrifugate, detecting N, P, K and essential trace element content, adjusting Ph6.5-7.0 according to the national standard of liquid fertilizer, adding N, P, K and other essential trace element organic compounds which are easily soluble in water, stirring thoroughly, adding 2.5-8% (w/v) chitosan oligosaccharide, and stirring thoroughly;

C. adding large-particle chitosan-cellulose-activated carbon composite adsorption resin, stirring, removing heavy metal, harmful metal ions, pesticide residue and harmful substances, adding 0.5-1% (w/v) potassium sorbate, high-speed centrifuging, sieving with 200-250 mesh sieve, and filling into a barrel filled with nitrogen or vacuumizing.

The application also discloses the method for preparing the dry shell powder containing the natural astaxanthin.

The method is simple and convenient due to the adoption of the technical scheme, the waste of fresh shrimps and/or crabs can be treated on site, residues can be thoroughly removed through enzymolysis of mixed protease and ultrasonic assistance, the food-grade antioxidant is added in the enzymolysis process, the oxidation of natural astaxanthin is protected, the natural astaxanthin content in the product is improved, the natural astaxanthin content of the dry shell powder is 200-250 mu g/g, and the dry shell powder can be directly added and used as feed (the application is disclosed as CN 108208313A) or used as a raw material for astaxanthin extraction.

In addition, according to the method, residual meat contained in leftovers after hydrolysis by mixed protease is prepared into concentrated protein powder, the shrimp shell is prepared into biological calcium powder by organic acidification, process wastewater and washing water are mixed to prepare a chitosan liquid fertilizer (plant nutrient solution), the process conditions are further optimized, and the dry shell powder rich in natural astaxanthin is prepared, so that the waste resource utilization of enterprises is realized, the economic benefit is greatly increased, and the pollution of waste to the environment is effectively reduced; realizing zero discharge of sewage.

Drawings

FIG. 1 is a HPLC check chart of astaxanthin standard control solution.

FIG. 2 is a HPLC check chart of a test solution of astaxanthin from shrimp meal.

Detailed Description

Example 1

The specific implementation steps taking crayfish as an example are as follows:

1. removing shrimp tails from fresh crayfish, and washing with deionized water; (30% of shrimp tails can be sold in the market);

2. pulverizing fresh crayfish head and shrimp foot into pulp (5-10 mesh shrimp shell) containing 50-55% water;

3. pumping fresh shrimp pulp into an enzymolysis reaction kettle equipped with an ultrasonic device (H66025 type ultrasonic generator: power: 50W-250W, frequency: 15kHz-50 kHz);

4. adding deionized water, wherein the solid-liquid ratio is 1: 2.5, and adjusting: pH =7.5, enzyme dosage is 8,000U/g, enzymolysis is carried out for 5.0h at 55 ℃, mixed enzyme preparation, namely papain, trypsin and lipase, is adopted, and the ratio is as follows: 1.5: 0.3: 0.2; simultaneously adding 500ppm of antioxidant vitamin E;

after enzymolysis and speed reduction, high-speed centrifugation is carried out, and (V =3000 r/min) centrifugate is transferred into a protein extraction process (7);

6. washing centrifugal slag with deionized water, and then, mixing the centrifugal slag with deionized water according to the proportion of 1: 1.5 (W: W), adding acid water for decalcification, (adding antioxidant L-sodium ascorbate 600ppm) acid is 1mol HCl, stirring for decalcification for 4-6h, accelerating, centrifuging at high speed, (V =3000 r/min) transferring centrifugate into a process for extracting bioactive calcium; according to the requirement of the product, organic acid can be adopted for decalcification, and the product is dried in vacuum (the water content is less than or equal to 10%) at the temperature of 60 ℃;

the finished product is packed by filling nitrogen or vacuumizing, and is externally provided with an aluminum foil light-shielding bag, and the refrigeration temperature is less than or equal to 5 ℃.

HPLC detection shows that the natural astaxanthin content in the dried shrimp shells is 200-250 mug/g;

7. protein extraction:

stirring the enzymolysis centrifugate → 100 ℃ for 0.5h (enzyme killing and sterilization) → controlling the temperature at 60 ℃, adding 5% (w: v) chitosan-cellulose-activated carbon composite adsorption resin (self-made), and stirring for 1 h; (decolorizing, removing fishy smell and heavy metal ions, removing residual and harmful substances), hot microfiltration, (removing particulate impurities), vacuum concentration (solid content is more than or equal to 10%) → spray drying to obtain concentrated protein powder (spray drying the feed liquid under the process conditions of air pressure of 0.3 MPa, inlet temperature of 150 ℃ and outlet temperature of 70 ℃).

Through detection: the shrimp meat sauce contains 6.21% of water, 3.05% of ash, 3.26% of fat and 87.48% of protein, and the shrimp meat sauce is rich in shrimp flavor, good in color and luster, powdery particles and very suitable for serving as a protein enhancer, a flavoring agent filler and the like.

8. Extracting bioactive calcium and organic biological calcium:

extracting bioactive calcium by adding K into centrifugate (containing hydrochloric acid Ph4) →₂CO₃Adjusting Ph6-6.5, introducing CO₂White precipitate is generated → high-speed filtration and centrifugation (V =3000 r/min) → centrifugal slag vacuum drying temperature is controlled at the temperature of less than or equal to 80 ℃, and moisture is less than or equal to 10%) → thus obtaining the finished product bioactive calcium; transferring the centrifugate (rich in protein, calcium and potassium ions) → to liquid fertilizer water.

Extracting organic bioactive calcium by centrifuging (containing citric acid, Ph6-6.5) → micro-filtering, (removing particulate impurities) → vacuum concentrating (solid content ≥ 10%) → spray drying to obtain organic bioactive calcium powder. (feed liquid is spray dried under the process conditions of 0.2 MPa of air pressure, 160 ℃ of inlet temperature and 80 ℃ of outlet temperature)

10. Preparing a chitosan oligosaccharide liquid organic fertilizer:

A. mixing the cleaning water for cleaning the shrimp heads and the residues and the cleaning water of the reaction kettle → adding a chitosan flocculant (self-made) for precipitation, taking supernatant (about 70%) → super-anion and cation resin → recycling as the cleaning water;

B. mixing the flocculation solution (about 30%), bioactive calcium centrifugate (rich in protein, calcium and potassium ions) → testing N, P, K and essential trace element content, and controlling liquid fertilizer national standard → adjusting Ph6.5-7 (using KOH and H)₂PO₃In addition, amount is reduced by Na⁺、Cl^-、SO₄ ^-Ions) are added → N, P, K and essential trace element organic compounds that are readily soluble in water,

stirring thoroughly for 1h → adding 2.5-3% (w/v) chitosan oligosaccharide (M is less than or equal to 5 KD), stirring thoroughly for 1h → adding 5% (w/v)

Large-grain chitosan-cellulose-activated carbon composite adsorption resin (self-made), stirring for 1h (removing heavy metal, harmful metal ions, pesticide residue and harmful substances), adding 0.5-1% (w/v) potassium sorbate (mildew-proof and preservative), centrifuging at high speed, sieving with a 200-250-mesh sieve → filling a barrel with nitrogen or vacuumizing (less than or equal to 0.1 MPa).

The oxidation loss of the astaxanthin in the storage and transportation links is 5-10 percent; meanwhile, the key deposit and logistics cost are reduced by 70%, and the invention has extremely high social and economic benefits.

Example 2 HPLC detection of Natural astaxanthin content in Cray shrimp head Shell product

1. Chromatographic conditions chromatographic column:

the chromatographic column is a Diamonsil C18 column (250 mm. times.4.6 mm, 5 μm);

mobile phase: methanol-water (95: 5): flow rate: 1 mL/min; detection wavelength: 475 nm;

a detector: an ultraviolet detector: sample size; 10 μ L of: column temperature, room temperature.

2. Measurement method

A. Preparation of control solution astaxanthin control 4.0mg was weighed precisely, placed in a 50mL measuring flask, dissolved by shaking with a small amount of dichloromethane (1mL), and diluted to the scale with methanol to give a control stock solution. Precisely transferring 2mL of the stock solution into a 10mL measuring flask, diluting to the scale with methanol, and shaking up to obtain a control solution.

B. The preparation of the test solution comprises weighing 12g of sample, precisely weighing, adding 60-80mL of dichloromethane for three times, respectively performing oscillation extraction, (controlling the temperature at 30 ℃ for 5-6h), filtering the three extraction solutions with 200-mesh suction filtration membrane when the shrimp shell is yellow white, concentrating to 5mL, adding 15mL of methanol, adding 5mL of 1.5% KOH methanol solution, performing ultrasonic treatment for 15min, and diluting to 25mL with solvent. The resultant astaxanthin extract was saponified in a refrigerator at 4 ℃ for about 7 hours in a dark environment, and the saponified astaxanthin extract was passed through a 0.45 μm membrane to obtain 5 test solutions, and the average value was calculated.

C. The sample solution and the control solution were each taken 10. mu.L, and injected into a liquid chromatograph to measure the peak area. The content of astaxanthin is calculated by peak area according to external standard method, and chromatogram is shown in fig. 1 and fig. 2.

D. The linear relationship determines: precisely sucking standard astaxanthin reference substance solution under item A, feeding 5, 10, 15, 20, 25 and 30 mu L of astaxanthin reference substance, carrying out linear regression treatment on the reference substance quantity (X) by using a peak area (Y), wherein the linear equation is Y = 53774X-7242.3, and r =0.9993, and the result shows that the feeding volume and the peak area have a good linear relation within 0.0802-0.4812/mu g.

E. The repeatability test takes astaxanthin test solution, 5 parts of test sample is prepared according to the method under item 2. B, peak area is measured according to the chromatographic condition under item 1, the content is calculated, the average content of the result is 107.6 mu g/mL, and RSD is 1.09%.

The average content of 12g of finished shrimp shell powder and 25mL of extracted concentrated solution is 107.6 mug/mL;

25ml×107.6μg/12g=224.6μg/g。

the previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention, including any reference to the above-mentioned embodiments. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A method for preparing a dry shell powder with high natural astaxanthin content from fresh shrimp and/or crab waste comprises the following steps:

1) crushing fresh shrimps and/or crab wastes for pulping to prepare fresh pulp;

2) pumping fresh slurry into an enzymolysis reaction kettle equipped with an ultrasonic device for enzymolysis by adopting a mixed enzyme preparation, wherein a food-grade antioxidant is added into the mixed enzyme preparation, and the adding amount of the food-grade antioxidant is 100-5000 ppm;

3) after enzymolysis, high-speed centrifugation is carried out, centrifugal slag is washed by deionized water, and acid water is added for decalcification;

4) and after decalcification is finished, centrifuging at a high speed, and drying centrifugal slag at 30-60 ℃ in vacuum to obtain dry shell powder containing natural astaxanthin.

2. The method of producing a dry shell meal high in natural astaxanthin from fresh shrimp and/or crab waste according to claim 1, wherein the animal source of the fresh shrimp and/or crab waste comprises one or more of sea shrimp, freshwater shrimp, crayfish and crab; the waste is in the form of one or more of shrimp head, rejected shrimp, shrimp leg, shrimp shell, crab leg, crab shell and rejected crab.

3. The method for preparing the dry shell powder with high natural astaxanthin content from the waste of fresh shrimps and/or crabs according to claim 1, wherein the power of an ultrasonic device is as follows: 50W-250W, frequency: 15kHz-50 kHz; the fresh slurry is 5-10 mesh in sheet shape, and has water content of 50-55%.

4. The method for preparing the dry shell powder with high natural astaxanthin content from the fresh shrimp and/or crab wastes as claimed in claim 1, wherein the solid-to-liquid ratio of enzymolysis is 1: 1.5 ~ 1:5, the pH is adjusted to be 7.0-8.0, the enzyme dosage is 5000-.

5. The method for preparing the dry shell powder with high natural astaxanthin content from the fresh shrimps and/or crabs waste according to the claim 4 or 5, characterized in that the mixed enzyme preparation comprises papain, trypsin and lipase, the papain, the trypsin and the lipase are mixed according to the proportion of U/g: 1-2: 0.2-0.5: 0.1-0.3.

6. The method for preparing the dry shell powder with high natural astaxanthin content from the fresh shrimp and/or crab wastes as claimed in claim 1, wherein the acid water is decalcified and added with acid water while adding food-grade antioxidant 100-2000 ppm; the acid water is low-concentration HCl or organic acid.

7. The method for preparing the dry shell powder with high natural astaxanthin content from the waste of fresh shrimps and/or crabs as claimed in claim 1 or 6, wherein the food grade antioxidant is one or more of vitamin E, vitamin C, L-sodium ascorbate, BHA, PG and BHT.

8. The method for preparing the dry shell powder with high natural astaxanthin content from the fresh shrimps and/or crabs waste according to claim 1, wherein after the high-speed centrifugation in the step 3), the centrifugate is transferred to a protein extraction process, and the protein extraction process comprises the following steps:

stirring the enzymolysis centrifugate at 100 deg.C for 0.5h, controlling temperature at 60 deg.C, adding 5% (w: v) chitosan-cellulose-activated carbon composite adsorption resin, stirring for 1h for decolorizing, removing fishy smell, removing heavy metal ions, and removing pesticide residue and harmful substances;

microfiltering to remove particle impurities while the solution is hot;

vacuum concentrating to solid content not less than 10%, and spray drying to obtain concentrated protein powder.

9. The method for preparing the dry shell powder with high natural astaxanthin content from the waste of fresh shrimps and/or crabs according to claim 1, wherein after the high speed centrifugation in the step 4), the centrifugate containing hydrochloric acid is added to K₂CO₃Adjusting Ph to 6-6.5, introducing CO₂White precipitate is generated, high-speed filtration and centrifugation are carried out, the centrifugal slag is dried in vacuum, the temperature is controlled to be less than or equal to 80 ℃, the water content is less than or equal to 10 percent, the finished product of the bioactive calcium is obtained, and the centrifugate is transferred into liquid fertilizer water;

or, after high-speed centrifugation in the step 4), carrying out microfiltration on the centrifugate containing the organic acid to remove particle impurities, carrying out vacuum concentration to obtain organic bioactive calcium powder with the solid content of more than or equal to 10 percent, and carrying out spray drying to obtain the organic bioactive calcium powder;

further, the method also comprises the preparation steps of the chitosan oligosaccharide liquid organic fertilizer:

A. mixing the cleaning water for cleaning the shrimp heads and the residues with the cleaning water of the reaction kettle; adding chitosan flocculant for precipitation, taking supernatant, passing through anion and cation resins, and recycling as cleaning water;

B. mixing the flocculation solution and the bioactive calcium centrifugate, detecting N, P, K and essential trace element content, adjusting Ph6.5-7.0 according to the national standard of liquid fertilizer, adding N, P, K and other essential trace element organic compounds which are easily soluble in water, stirring thoroughly, adding 2.5-8% (w/v) chitosan oligosaccharide, and stirring thoroughly;

C. adding large-particle chitosan-cellulose-activated carbon composite adsorption resin, stirring, removing heavy metal, harmful metal ions, pesticide residue and harmful substances, adding 0.5-1% (w/v) potassium sorbate, high-speed centrifuging, sieving with 200-250 mesh sieve, and filling into a barrel filled with nitrogen or vacuumizing.

10. Dry shell flour containing natural astaxanthin obtained by the process according to any one of claims 1 ~ 10.