1. Technical Overview

Carbon dioxide supercritical fluid extraction (CO2 SCFE) provides nutraceutical extracts with the highest possible purity and concentration because supercritical CO2 can separate the required ingredient more selectively than solvent extraction [1].

Figure 1. Nutritional supplements improve strength and endurance
Image credits: Steve Buissinne at Pixabay

Earlier, hexane and acetone extracted astaxanthin from Haematococcus pluviales, a microalga with astaxanthin and an astaxanthin-lipid combination. These organic solvents provided low-concentration extracts because they cannot differentiate between astaxanthin and lipids.

Aromatherapy utilizes essential oils. The relatively low process temperatures of CO2 SCFE prevent thermal degradation of essential oils, an issue that plagues hydrodistillation [2]. CO2 SCFE also avoids unwanted ingredients in the final extract as is the case with organic solvents [2].

CO2 SCFE apart, other techniques to extract essential oils are [3]:

  • Hydrodistillation
  • Solvent Extraction
  • Cold Press Extraction
  • Maceration
  • Resin Tapping

2. Nutraceutical & Aromatherapy Markets

2.1. Nutraceutical Market

Rapid growth will place the global nutraceutical market at $373 billion in 2025 [4]. Aromatherapy is an in-demand, non-conventional treatment option whose global market is forecasted to expand to $2.8 billion by 2026 [5].

Enormous medical treatment costs make prevention a better option. This explains the skyrocketing demand for nutraceuticals, particularly functional foods and beverages containing herbal extracts and food reinforced with omega-3 fatty acid [6]. Following factors push ahead the nutraceutical market:

  • Rising demand for health supplements in view of the growing incidences of lifestyle disorders and non-communicable diseases [7].
  • Popularity of anti-ageing among the elderly in Europe are boosting the nutricosmetics market [7].
  • Innovative products with function-specific antioxidants [6].
  • Better packaging options developed by the industry [4].

2.2. Aromatherapy Market

Aromatherapy releases hormones such as oxytocins and endorphins, something that makes massage and spa therapists as well as gym trainers employ the practice to treat stress, insomnia, alopecia areata, pain, anxiety, agitation etc [8]. Increasingly, people prefer aromatherapy for treating acne, burn scars, respiratory and cardiovascular disorders, indigestion, and cough and cold, as also for boosting immunity and healing wounds [9].

Chief drivers of aromatherapy are [8]:

  • Alternative treatment with zero or minimal side effects.
  • Robust distribution network of essential oil manufacturers simplifies aromatherapy delivery.
  • Greater use of aromatherapy diffusers in homes as room fresheners.

3. Supercritical Fluid Extraction (SCFE) & Carbon dioxide (CO2) SCFE

3.1. Why SCFE Use is Rising?

Regulations on toxicity, quality, safety, and residues in consumer products are getting stricter as consumers demand products with more natural ingredients in food-beverage, pharmaceutical, nutraceutical, and personal care products. SCFE is safer, more eco-friendly, and leaves behind zero or less toxic residues in the final product.

Alternative methods have drawbacks:

  • Solvent Extraction: uses toxic organic solvents whose residue cannot be completely separated from the extracted ingredient [10]. Some solvents deplete the ozone layer and create environmental issues [11].
  • Hydrodistillation: employs heat which can thermally degrade the ingredient [12].

3.2. What are Supercritical Fluids & How do they Assist with Extraction?

A fluid at above its critical pressure and temperature is a supercritical fluid. The phase boundary between its liquid and vapour phase disappears and its properties can be customized by changing the pressure and temperature.

Roughly, supercritical fluids with higher density possess greater solvent power. And because altering pressure and temperature substantially varies their density, supercritical fluids make exceptional solvents.

Figure 2. Triple Point Parameters

Supercritical fluids are excellent solvents because of their [13]:

  • Higher, Liquid-like Density: boosts solvent power.
  • Low, Gas-like Viscosity: improves mass transfer and diffusion inside porous solids.
  • Low, Gas-like Surface Tension: enables greater seepage inside porous solids.

3.3. Why Supercritical Carbon dioxide (CO2) Makes an Excellent SCFE Solvent?

Carbon dioxide and water are the most popularly utilized supercritical fluids [14]. Supercritical (CO2) is an ideal solvent for SCFE because it [13]:

  • Has a critical temperature of 31.10C, which is around the ambient temperature. Relatively low temperatures for CO2 SCFE avoid thermal degradation.
  • Has a more manageable critical pressure of 73.9 bar.
  • Is non-flammable and non-toxic.
  • Has a customizable density to upgrade its solvent power.
  • Is available in ample quantities and in pure form.
  • Has a comparatively low cost.

Although CO2 is a greenhouse gas (GHG), the SCFE process using CO2 becomes eco-friendly if the gas is captured from the atmosphere, reused, and recycled.



Buffalo Extraction Systems Technologies believes in the power of nature. Visit our pilot plant for complete product trials and you will feel our expertise accumulated over 28 years experience in supporting a global clientele across a diverse range of automation and process equipment.

Contact us at +91 20 6790 9600 or sales.automation@cybernetik.com and feel top-of-the-shelf professionalism.




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  4. The Global Market for Nutraceuticals Set for Robust Growth. Healthcare Packaging.


  5. Aromatherapy Market Size Worth $4.19 Billion by 2029. Grand View Research.


  6. Nutraceuticals Market. Allied Market Research.


  7. Nutraceuticals Market – Growth, Trends, and Forecast (2020-2025). Mordor Intelligence.


  8. Aromatherapy Market. Future Market Insights.


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