Supercritical CO2 extracts display some of the characteristics of both essential oils and absolutes. Like essential oils, they contain many beneficial therapeutic properties. But unlike absolutes, they are not solvent extracted.
The composition of a supercritical CO2 or subcritical CO2 extract is generally different from the equivalent essential oil. Because of these differences, CO2 extracts can have distinct therapeutic properties. For example, Ginger CO2 contains gingerols, constituents that give ginger its pungent taste. There two principal types of CO2 extract:
• Select extracts: are generally more similar to essential oils
• Total extracts: contain more heavier molecules and could be compared to absolutes.
Because the plant material is not exposed to air (oxygen) or heat, as compared to steam distillation, none of the compounds change or oxidises during extraction. Hence, the final extract is just the same as in the plant – the same composition and aroma. In the case of German Chamomile CO2 extract, matricin is not converted to the dark blue chamazulene, as in the steam distilled oil.
Major benefits of CO₂ extracts
• Extractions occur at lower temperatures than steam distillation, so more delicate botanicals are not destroyed
• Carbon dioxide is nontoxic, odorless, and is easily removed from the extracted oil
• More stable with a long shelf life
• Contain no carbohydrates, inorganic salts, proteins, allergens, or germs
• Meet strict heavy metal requirements