Extraction with emerging technologies process intensification
The objective of extraction is to recover valuable soluble components from raw materials by primarily dissolving them in a liquid solvent, so that the components can be separated and recovered later from the liquid. It is not always the objective to recover one particular compound in pure form from a raw material, i.e. sometimes extraction is intended to separate all the soluble compounds from the residue; an example of this is the extraction of coffee.
Extraction is applied to a wide variety of food products. Typical examples are:
- the extraction of sugar from sugar-beets or sugar-cane
- the extraction of oil from oil seeds and from virgin pomade
- the extraction of coffee extract from coffee beans
- the extraction of caffeine from coffee beans
- the extraction of various other compounds such as proteins, pectins, vitamins, pigments, essential oils, aroma compounds, flavour compounds etc. from many different materials.
(European Commission, 2006)
Further Information: Extraction in food industry
Description of technology, techniques and methods
High Pressure Processing (HPP)
The technology help to improve the mass transfer’s rate, reduce extraction time and increase extraction yield. This is due to the effect on solvent permeability in cells, the solubility of extractable compounds and inactivation of degradation of enzymes.
(Tao, Sun, Hogan, Kelly, 2014)
Further Information: HPP
Ultrasound enables a greater penetration of solvent into cellular materials. Disruption of cellular walls facilitating the release of content. Micro streaming effects for better diffusion. Higher level of dry matter and final content. Improved process for organic compounds within the body of plants and seeds. Fundamentally implies increasing efficiency of extraction at lower temperature in less time. For tea extraction there was an improvement of 20% and most of the component were extracted in the first 10 minutes of operation.
Further Information: ultrasound
The technology enables rapid heating of the solvent and sample, reduction of solvent use and time processing, and higher extraction rate become possible. There is a volume expansion at micro scale leading to explosions at cellular level, making easier the diffusion processes/ mass transfer.
Wider range of solvent can be used (less reliance on chemical affinity).
Extraction of targeted compounds becomes a possibility.Solvent free micro wave extraction has been developed by the combination with dry distillation at atmospheric pressure. It was used in essential oils extraction from aromatic herbs. A more simply, economically, quickly way than conventional method was the product. Promising synergies with ultrasonic technology.
(Ozkoc, Sumnu & Sahin 2014)
Further Information: microwaves
The technology enables an improved mass transfer proportional to the electric field and to area of the sample (proved in Juice extraction yields improvement). By lowering the frequency of alternative current can also improve the yield of extraction Reduction in extracting time of almost 80% is possible. Lower energy need comes naturally. Synergy of electrical and thermal effects on cell tissues, a lower temperature is needed for effective membrane damage and the lower electric field applied and simplification equipment is possible compared to pulse electric field.
(Goullieaux & Pain, 2014)
Further Information: Ohmic
Pulse Electric Field (PEF)
Applications for Juice, sugar and oils extraction are made easier than conventional. The time reduction is major advantage due to the improved mass and heat transfer capacity (60% less time needed in some cases).
(Griffiths, Walking-Ribeiro, 2014)
Further Information: PEF
Changes in the process
Energy saving potentials
Most of the technologies enable relevant processing time reductions.
Changes in the energy distribution system
The use of the emerging system for extraction puts more pressure in the electricity system and less in the thermal energy system. The intensification of the operation towards an accelerated processing may demand more electric power making space for innovation in the electrical system. A possibility for this is energy cascading, which depend of the power needs and help to address the opportunities for renewable energy sources.
- European Commission (2006) Best Available Techniques (BAT) in the Food, Drink and Milk Industries. Reference Document: Best Available Techniques [Online]. Available at: http://eippcb.jrc.ec.europa.eu/reference/BREF/fdm_bref_0806.pdf (Accessed: 20th February 2015).
- Goullieaux A., Pain J.P. (2014) 'Part IV: Alternative thermal processing: Chapter 22 Recent Development in Microwave Heating', in Sun, D. (ed.)Emerging Tehcnologies for Food Processing. UK: Academic Press, pp. 361-377.
- Griffitths M. W., Walking-Ribeiro, M. (2014) ' Part II: Chapeter 7 Pulse Electric Field processing, in Sun, D. (ed.)Emerging Tehcnologies for Food Processing. UK: Academic Press, pp. 115-138.
- Muredzi, P. (2012) 'Chapter 5: Ultrasound Processing Technology', in Aleman, M. (ed.) Emerging Non-thermal Food Processing Technologies. USA: CBH books, pp. 167-194.
- Ozkoc S., Sumnu G., Sahin S. (2014) 'Part IV: Alternative thermal processing: Chapter 20 Recent Development in Microwave Heating', in Sun, D. (ed.)Emerging Tehcnologies for Food Processing. UK: Academic Press, pp. 361-377.
- Tao, Y., Sun D., Hogan E., Kelly, A. (2014) 'High pressure processing', in Sun, D. (ed.)Emerging Technologies for Food Processing. UK: Academic Press, pp. 3-20.