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Extraction Process of Astaxanthin from Crayfish: CO2 & Etc

Supercritical CO2 Extraction of Astaxanthin from Crayfish Shell

Astaxanthin is a terpene unsaturated compound that belongs to the carotenoid family, and it has a pink color. It is known for its important biological functions, which include preventing ultraviolet radiation damage, improving the immune system, and helping to prevent cardiovascular diseases.

The supercritical CO2 fluid extraction method is being used to extract Astaxanthin because it is a more environmentally friendly and efficient process. Astaxanthin indeed has many important biological functions, and its applications in various fields, including medicine, food, and cosmetics, are immense. Its abilities to prevent ultraviolet radiation, improve immunity, and prevent cardiovascular diseases make it a valuable compound.

Top 4 Extraction Process of Astaxanthin from Crayfish

Typically, the extraction process for astaxanthin involves pulverizing the shrimp shells and extracting them with chemical solvents such as ethanol or acetone. Subsequently, astaxanthin can be isolated from the extract by steps such as evaporation, precipitation, and filtration.

Organic solvent extraction

Organic solvent extraction is a traditional astaxanthin extraction method. The principle of this method is to mix crayfish shell powder with organic solvents (such as ethanol, acetone, ethyl acetate, etc.), and then perform operations such as soaking and ultrasonic treatment to dissolve astaxanthin from the shell. Then, the solvent is volatilized by rotating the extract or concentrating under reduced pressure to obtain the crude extract of astaxanthin. This method is simple to operate but requires a large amount of solvent, and the purity of astaxanthin is low.

Acid-base extraction

The acid-base extraction method is to react crayfish shell powder with strong acid or strong alkali to separate astaxanthin and protein in the shell. Then the separated astaxanthin is purified through neutralization, precipitation, filtration, and other steps. Although this method can improve the purity of astaxanthin, it requires a high technical level and is easily affected by environmental pollution.

Supercritical CO2 extraction

The supercritical fluid extraction method uses supercritical fluid (such as CO2) as a solvent, mixes crayfish shell powder with a supercritical fluid, and extracts astaxanthin from the shell under high pressure and high-temperature conditions. Compared with the traditional organic solvent extraction method, the supercritical fluid extraction method has the advantages of environmental protection, high efficiency, and good controllability, and the extracted astaxanthin has a higher purity.

Microwave Assisted Extraction

The microwave-assisted extraction method is to add a small amount of solvent to the crayfish shell powder and use microwave heating technology to extract astaxanthin from the shell. This method has the advantages of fast extraction speed and simple operation but requires certain microwave equipment and technical support.

The CO2 extraction method for astaxanthin from Crayfish shell

CO2 Essential Oil Extraction Equipment

Accurately weigh the 4.7647g crayfish shell powder sample and place it in the extraction kettle, put the filter cotton and filter discs into the extraction kettle before loading the sample, and cover the extraction kettle cover. After the preparation work is completed, the extraction test is carried out. The set extraction pressure is 30MPa, the CO2 flow rate is 30L/h, the separation temperature is 40°C, the trainer is 1 times the amount of 95% ethanol, the extraction time is 120min, the extraction temperature is 50°C, and the extract is a red liquid.

CO2 extraction process

  1. Extraction pressure: 300 bar;
  2. Extraction temperature: 50°C;
  3. Cosolvent: Double the dose of 95% ethanol of the raw material
  4. Separation pressure: 100 bar;
  5. Separation temperature: 40°C;
  6. Extraction time: 2.5h;
  7. Material particle size: 0.425μm.

Validation of 7 process parameters for CO2 extraction

CO2 flow

The fixed extraction temperature is 50℃, 95% ethanol is the trainer, the extraction pressure is 30MPa, the sample particle size is 0.425mm, the separation temperature is 40℃, the extraction time is 2h, and the CO2 flow rate is 10, 20 respectively. Under the conditions of, 30, 40, and 50L/h, explore the effect of CO2 flow rate on astaxanthin yield. When the CO2 flow rate is 10~30L/h, the astaxanthin yield in the sample increases with the increase in flow rate, but when the flow rate reaches At 30L/h, the increase in astaxanthin yield in the sample tends to be flat.

Considering that an excessive increase in the CO2 flow rate will lead to an increase in production costs, therefore, the CO2 flow rate is selected as 30L/h.

Extraction temperature

small co2 extraction machine for sale

With other conditions unchanged, the extraction temperature was selected to be 30, 35, 40, 45, and 50°C to study the effect of temperature on the yield of astaxanthin.

When the extraction temperature is in the range of 40~50℃, the yield of astaxanthin increases with the increase in temperature. When the extraction temperature is 50℃, the yield reaches the maximum; when the extraction temperature exceeds 50℃, the yield decreases as the temperature increases. the trend of.

Generally speaking, as the temperature rises, the solubility of astaxanthin in the extractant will increase, which is beneficial to the extraction. However, when the temperature is too high, it will also cause the loss of the extractant to increase, resulting in the production of astaxanthin. The extraction rate is reduced, which is unfavorable for extraction. Therefore, the optimal extraction temperature condition is 50°C.


With other conditions unchanged, we investigated the entrainment of 0.5 times the amount of 95% ethanol, 1 time the amount of 95% ethanol, 2 times the amount of 95% ethanol, 1 time the amount of 30% ethyl acetate, and 2 times the amount of 30% ethyl acetate. The effect of the agent on the extraction rate of astaxanthin.

With the increase of the entrainer dose, the yield of astaxanthin increased, but when the entrainer was increased to 1 time, the yield did not increase. For different entrainers, the extraction rate of 30% ethyl acetate solution as the entrainer is slightly higher than that of 95% ethanol. But considering that ethyl acetate will remain in the sample, it is difficult to remove, and ethanol will be completely volatilized, so choose 1 times the amount of 95% ethanol as the entertainer.


With other conditions unchanged, the effects of extraction pressures of 30, 35, 40, 45, and 50 MPa on the yield of astaxanthin were investigated. When the pressure was 20 to 30 MPa, the yield gradually increased, and the yield when the pressure reached 30 MPa. It is the highest value. When the pressure reaches 30 MPa, the yield increase is not obvious. Considering the cost, the supercritical extraction pressure is selected as 30 MPa.

Particle size

Under the condition of other conditions unchanged, choose the material size to extract astaxanthin from crayfish under the conditions of 2.000, 0.850, 0.425, and 0.180mm, respectively, and explore the influence of the material size on the yield of astaxanthin. The material size is 0.180~ At 2.000mm, the yield gradually increases, and when the particle size of the material is 0.425mm, the astaxanthin extraction rate reaches the highest value.

Because the smaller the particle size of the sample, the larger the contact area with the extraction solvent, and the higher the astaxanthin yield. However, particles with too fine a particle size are easy to agglomerate, which affects the extraction effect. Therefore, the optimization material particle size is 0.425. mm.

Separation temperature

When other conditions remain unchanged, set the separation temperature to 25, 30, 35, 40, and 45°C to discuss the effect of the separation temperature on the yield of astaxanthin.

As the separation temperature increases, the yield of astaxanthin gradually increases. A higher yield can be obtained when the separation temperature is 40°C, but the temperature continues to rise, and the yield shows a downward trend. When the temperature exceeds 40°C, the molecular weight The increase of the attractive force between the molecules reduces the molecular distance, but the molecules are in motion, which will prevent the molecules from approaching all the time and reaching equilibrium. The higher the temperature, the greater the molecular kinetic energy, which will increase the molecular distance, which is not good for extraction. , And consume more energy, therefore, choose the appropriate separation temperature is 40 ℃.


With other conditions unchanged, set the extraction time to 1.0, 1.5, 2.0, 2.5, and 3.0h respectively to study the effect of different extraction times on the yield of astaxanthin. When the extraction time is 1~2h, the yield gradually increases. When the extraction time reaches 2h, a higher yield can be obtained, but if the extraction time continues to increase, the yield shows a gentle trend and consumes more energy, so the optimization extraction time is selected as 2h.

To sum up

High-performance liquid chromatography was used to detect the content of astaxanthin in shrimp shells, and finally, the yield of astaxanthin in the sample was 26.13μg/g. The precision and recovery rate tests were conducted 6 times respectively, and the relative standard deviation was 0.10%, and the average recovery rate was 99.0%, both of which were within the scope of the national standard and conformed to the national standard. Astaxanthin has a good linear relationship in the linear range of 0-12μg/mL, and the detection limit is 0.01μg/mL. High-performance liquid chromatography is easy to operate, has low consumption, has high sensitivity, high precision, and a good recovery rate. It can be used as a detection method for astaxanthin.

The supercritical CO2 extraction method is used as the extraction method of astaxanthin. In consideration of economic benefits, the CO2 flow rate is 30L/h, and the astaxanthin yield reaches the maximum when the extraction temperature is 50℃, and the entrainer is 1 times the amount of 95 The extraction effect is optimization in% ethanol. Considering the production cost, the supercritical extraction pressure is 30MPa and the material particle size is 0.425μm when the yield is the highest. The most suitable separation temperature is 40℃, the extraction time is 2h, and the yield reaches the maximum. value.

It shows that the optimization of extraction conditions is scientific and reliable, and can provide a basis for the extraction of astaxanthin.