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Supercritical CO2 extraction: 5 keys to explain natural pigments

Supercritical CO2 extraction of natural pigments

Natural pigment

Natural pigments are edible pigments obtained from natural resources and are widely used colorants in the food industry, cosmetics industry and pharmaceutical industry.
Pigments are mainly extracted from animal and plant tissues and microorganisms (cultivation), of which plant colorants account for the majority. Natural pigments not only have the effect of coloring food, but also a considerable part of natural pigments have physiological activities.


Natural pigments derived from the roots, stems, leaves, flowers, fruits, animals, microorganisms, etc. of natural plants. Edible pigments are called natural food pigments. From the perspective of the added amount, the proportion of food pigments in food is very small. For products, a few thousandths, a few thousandths or even a few hundred thousandths of beverages, alcohol, cakes, candies, medicines, etc.

Although natural colorings are widely allowed as food colorings, the definition and licensing of natural food colorings are different in different countries. Some substances are recognized as flavors rather than colorings, so many spices are not recognized as colorings.

Take Sweden as an example. The country recognizes that turmeric, chili, saffron and sandalwood are not pigments but spices. Other countries such as Italy, the Netherlands, Switzerland and Norway have similar provisions in their food regulations.

Development and application

The development and application of natural pigments has become a topic of common concern for scientific and technological workers in various industries.

People try to obtain natural pigments from various animal and plant resources, and at the same time explore their physiological activities, to alleviate and solve various problems caused by synthetic pigments.

However, due to the unstable color of natural pigments, it is easy to be affected by various factors (such as light, temperature, oxidation, pH value, media polarity, metal ions, additives, etc.) during its use, resulting in changes in fading, discoloration, etc. , And affect its coloring effect, seriously restricting the process of replacing artificially synthesized pigments with natural pigments.

With the understanding of the chronic toxicity and teratogenic carcinogenicity of synthetic pigments, people desire to be healthy and return to nature, so the development of edible natural pigments has set off a climax.

Natural pigments have been proved by humans for thousands of years: most of them are non-toxic, some of them are nutritional sources or have relatively strong health care functions. For example, carotene is an important nutritional fort It also plays a significant role in preventing cardiovascular and cerebrovascular diseases.


As an important food additive, edible natural pigments have many beneficial properties:

  • Edible natural pigments come from the tissues of animals, plants, and microorganisms, so most of them have no side effects and are highly safe;
  • Some edible natural pigments are themselves a nutrient and have nutritional effects;
  • Food natural pigments can better imitate the color of natural objects, and the hue is more natural.

Plant pigments

Most plant pigments have no side effects and are highly safe.
Plant pigments are mostly anthocyanins, carotenoids, and flavonoids. They are a class of biologically active substances and are functional and effective ingredients in botanicals and health foods.


In view of the fact that plant pigments are used as coloring additives in food, medicine and cosmetics, the dosage cannot reach the dose-effect ratio of medical and health products.

In the application of health food, this kind of plant pigments can play auxiliary functions such as enhancing human immune function, anti-oxidation, and reducing blood lipids;
Some ordinary foods can play a supplementary role in nutritional fortification and antioxidant effects.


  • The color tone of plant pigments is relatively natural, which can increase the tone and is similar to the natural color. It is a kind of natural beauty.
    The content of plant pigments in plants is relatively small, and it is difficult to separate and purify. Some of the coexisting substances may also produce peculiar smells, so the production cost is higher than that of synthetic pigments.
  • Most plant pigments are sensitive to light, heat, oxygen, microorganisms, metal ions, and pH changes, and have poor stability; some plant pigments must be added with oxidants and stabilizers in use to increase the product’s life cycle.
  • Most plant pigments have poor dyeing power and are not easy to dye evenly. They do not have the bright and bright color of synthetic pigments.

There are many kinds of plant pigments and their properties are complex. As far as a plant pigment is concerned, it has strong application specificity, and its application range has certain limitations.

Japan is the most advanced country in the development of natural food pigments, followed by the United States, and China ranks third.


Natural pigments are generally derived from natural ingredients, such as beet red, grapes and peppers. These foods have been recognized and accepted by consumers. Therefore, natural pigments from these food sources can be more favored by consumers and are more suitable for use. Be safe.

Due to the use of natural pigments, some products have less artificial factors in their appearance, so they are closer to the natural form, thereby attracting more consumers.

Extraction of natural pigments

Traditional crafts

The products produced are of poor quality, low purity, peculiar smell and solvent residues, which have seriously affected the promotion and use of edible natural pigments

Supercritical CO2 fluid extraction

Supercritical CO2 extraction of natural pigments
Supercritical CO2 extraction of natural pigments

Compared with the traditional organic reagent method, the products produced by the supercritical CO2 fluid extraction technology have no solvent residues and no pollution, which can avoid the thermal degradation of the extract at high temperatures, protect the activity of physiologically active substances, and maintain the naturalness of the extracted materials. Flavor etc.

Therefore, supercritical CO2 fluid extraction technology has been applied to the extraction and purification of natural food colorings such as capsanthin, lycopene, β-carotene and gardenia yellow.

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