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Supercritical CO2 Extraction and Fractionation Refining of Capsanthin


Supercritical CO2 Extraction and Fractionation Refining of Capsanthin

Capsanthin is a natural pigment extracted from the peel of mature pepper. It has good performance and can be widely used in the coloring process of food, medicine and cosmetics.

Method of supercritical CO2 extraction of capsanthin

The production of traditional capsicum red pigment adopts traditional solvent extraction method, and its products have the defects of poor purity, peculiar smell and high solvent residue.

The oily characteristics of capsaicin make the capsicum pigment products obtained by organic solvent extraction and separation have higher solvent residues, and it is difficult for products to reach the United Nations Food and Agriculture Organization and the World Health Organization (FAO/WHO, 1984) by using general eluent methods. The latest standards stipulated have greatly affected the practicality of pepper pigments.

The use of supercritical CO2 fluid extraction and fractionation method can better achieve this purpose.

Supercritical CO2 fluid extraction technology

Supercritical CO2 fluid extraction is a new type of chemical separation technology.

The key to supercritical CO2 extraction technology is to understand the dissolving power of supercritical fluid and its changing law with the influence of many factors.


Supercritical CO2 fluid extraction (SCFE-CO2) is an extraction process that uses CO2 fluid above the critical temperature and critical pressure as the solvent.

  • The fluid near the critical point not only has a very high dissolving power for the substance, but the solubility of the substance will change with the pressure or temperature of the system;
  • Thus, by adjusting the pressure or temperature of the system, different substances can be selectively extracted and separated conveniently.
  • Supercritical separation technology has simple process, low energy consumption, non-toxic extraction solvent, easy to recycle, the product obtained has extremely high purity, and the residual solvent meets the requirements of FAO/WHO.

SFE system composition

Supercritical CO2 fluid extraction equipment for extraction of pepper pigments. The equipment is mainly composed of four parts: gas supply system, supercritical CO2 fluid generation system, extraction separation system, and metering system.

Best extraction conditions

The best extraction conditions are particle size <1.2mm, extraction pressure 15MPa, and extraction temperature 50℃.

In the extraction process, the separation effect of capsaicin and capsaicin was judged according to the absorbance curve of 200~600nm measured by UV3000 ultraviolet-visible spectrophotometer.

Measure the absorbance at 449nm with the acetone solution of the pigment, and the value obtained is the color value of the pigment. The quality indicators of the chili pigment extracted by this method exceed the national standards.

Refining of capsanthin by Supercritical CO2 Fractionation Technology

Supercritical CO2 Fractional Distillation Method for Refining Capsanthin

In order to comprehensively investigate the solubility of capsanthin in supercritical CO2 fluid, a linear boost operation mode was used to completely separate capsicum oleoresin.

Under lower pressure, the yellow and spicy components are mainly extracted. With the increase of pressure, the distillate of red pigment also increases. From the separation results, the extraction pressure to retain the red pigment under the selected conditions should be less than 10.0 MPa;

The extraction capacity of supercritical fluid under the selected conditions is very strong. When the pressure is more than 12.0MPa, the red components in the capsicum oleoresin can be basically extracted completely.


The supercritical CO2 fluid fractionation (SFEF) method can effectively remove the yellow and spicy components in the pigment under lower pressure, and at the same time, the red pigment and more insoluble components can be realized when the pressure continues to rise to a certain extent. Such as the separation of resin and pectin, in this way, high-quality capsicum red pigment with complete depigmentation and low impurity content can be obtained.

The loss of red color value in the separation process is about 5%, which has obvious advantages over the traditional depigmentation process.

The SFEF method can not only effectively remove the peculiar smell and impurity residues in the crude product, but also can obtain the refined product with a small loss of the total color value.

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