Foods | Uses for Supercritical Fluids

Why Supercritical CO₂ Food Processing?

Demand for safe foods has led to stringent government regulations

on the use of organic solvents in the food processing industry.

The need to replace toxic organic solvents with an environmentally

benign, non-flammable, and inexpensive alternative has led to the rapid development of supercritical CO₂technology in the food industry. The supercritical CO₂ process is cleaner and the extracts obtained have longer shelf life and better blending characteristics due to co-extraction of antioxidants and lipids.

Previously, chlorinated solvents were used for extraction of hops and the decaffeination of coffee resulting in residual toxic solvents remaining in the food products. Chlorinated solvents are now banned in the food industry, but other solvents are still in use today. For example, hexane is the solvent most commonly used today in the food industry for the extraction of oil from oil seeds. However, in the USA, the residual hexane content in food products has to be less than 25 ppm and the limit is expected to be reduced to a lower level. In Japan and Europe, even 25-ppm hexane in extracts is to be banned.  A similar trend is observed in other applications using different organic solvents as well. The trend is gaining momentum and thus organic solvent extraction processes may be phased out in the near future.

The advantages of SCF extraction over conventional solvent extraction are:

1. CO₂ requires only moderate temperatures of operation

2. CO₂ is Non-toxic, non-flammable, and Generally Recognized As Safe (GRAS)

3. CO₂ is a volatile solvent and upon depressurization, no toxic solvent residues remain in the product

4. CO₂ has good mass transfer, due to the low viscosity of the solvent

5. CO₂ is a selective solvent based upon its variable density (e.g. extraction of caffeine from green coffee without removal of flavor precursors)

6. CO₂ has a low overall energy expenditure and there is no energy consumption for desolventizing an extract.

The main commercial scale food applications using supercritical CO₂ processing are:

1. Extraction of hops for beer production
2. Decaffeination of coffee and tea
3. Nicotine/tar-free tobacco
4. Separation of Free Fatty Acids from vegetable oils
5. Fractionation of Poly Unsaturated Fatty Acids from animal lipids
6. Refining and deodorization of vegetable oils
7. Recovery of antioxidants (vitamins E and A)
8. Fractionation of glycerides
9. Extraction of oil from oil-bearing materials
10. Deoiling and purification of lecithin
11. Decholesterolization of butter, egg, fish and meat muscle
12. Deoiling of snack-foods
13. Spice extracts (oil and oleoresin)
14. Flavours and fragrances extraction
15. Extraction of natural food colors
16. Extraction of natural food preservatives
17. Natural extraction of Herbs for natural medicines
18. Extraction of natural pesticides from Neem
19. Production of cholesterol-free food products

At Applied Separations, we have a proven commitment to advancing Supercritical Fluids technology and have worked with companies all over the world to incorporate SCF into their processes. Thanks to a top-notch R&D team, in-house engineers, and visionary approach, we're working hard to develop and enhance applications of this green technology in many unexpected industries.