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 CO2 technology 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 UK, the residual hexane content in food products has to be less than 1 mg/kg (1ppm) in the oil, thus organic solvent extraction processes may be phased out in the near future.

The advantages of supercritical fluid extraction over conventional solvent extraction are:

  • CO2 requires only moderate temperatures of operation
  • CO2 is Non-toxic, non-flammable, and Generally Recognised As Safe (GRAS)
  • CO2 is a volatile solvent and upon depressurisation, no toxic solvent residues remain in the product
  • CO2 has good mass transfer, due to the low viscosity of the solvent
  • CO2 is a selective solvent based upon its variable density (e.g. extraction of caffeine from green coffee without removal of flavour precursors)
  • CO2 has a low overall energy expenditure and there is no energy consumption for desolventising an extract.

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

  • Extraction of hops for beer production
  • Decaffeination of coffee and tea
  • Nicotine/tar-free tobacco
  • Separation of free fatty acids from vegetable oils
  • Fractionation of poly-unsaturated fatty acids from animal lipids
  • Refining and deodourisation of vegetable oils
  • Recovery of antioxidants (vitamins E and A)
  • Fractionation of glycerides
  • Extraction of oil from oil-bearing materials
  • De-oiling and purification of lecithin
  • De-cholesterolisation of butter, egg, fish and meat muscle
  • De-oiling of snack-foods
  • Spice extracts (oil and oleoresin)
  • Flavours and fragrances extraction
  • Extraction of natural food colours
  • Extraction of natural food preservatives
  • Natural extraction of herbs for natural medicines
  • Extraction of natural pesticides from neem
  • Production of cholesterol-free food products

Applied Separations have a proven commitment to advancing Supercritical Fluids technology and have worked with companies all over the world to incorporate supercritical fluid extraction (SFE) into their processes. Thanks to their world class R&D team, in-house engineers, and visionary approach, Applied Separations work hard to develop and enhance applications of this green technology in many unexpected industries.

Have an application in mind? Please contact iBiosys Solutions and, together with Applied Separations, we will work with you to develop a supercritical fluid application fit for your needs.