The supercritical CO2 extraction is, beyond all doubt, the best extraction technique available today. It is the best not only for the quality of its extracts, but also for the absence of contamination. For this reason, the exhausted matrix (flour, etc. ..) can be used without any fear, which is impossible for solvent extraction. It is the best for its rapid process (hours instead of days) and the presence of a reducing environment in which the oxidation can not occur. Is the best because it is the only true green technology: it does not pollute, there are no solvents or even exhausted to dispose of. It is the best because it is the only one that can transform waste products (which represent only a cost) in high value-added active ingredients that would otherwise be acquired by large pharmaceutical companies at a high price. For a long time, the poorest technologies (processes with chemical solvents) were more spread. But today we all realize the damage caused by chemical solvents to human health and very soon (in Europe since 2012) they will be banned worldwide. It is clear that today, from an economic standpoint, investment in traditional technologies that use chemical solvents has no future. The reasons for economic, technical and policy underlying the choice of technology proposal are the following:
Supercritical CO2 extraction benfits and versatility.
1) The characteristics of CO2 extraction technology are versatility combined with eco-friendly, acting in transformation processes on two different levels:
- in the initial processing phase of vegetable raw materials and in the entire food chain. SCF extraction works directly on raw materials, eg in the processing of the must SCF occurs just after the crushing of grapes. In addition, waste materials are used as primary products, (those parts that are currently disposed of) because with this technology can be found re-employment as a source of antioxidants. Following the same chain processes, SCF may also be applied in subsequent stages. In fact, SCF interventions can be included in the processing of waste (seeds and grapes), pasteurization of grape juice, into wine and brandy dealcoholization obtaining new products. In the olive sector intervention may be even more “vertical” and significant because in the extraction stage you can get a very high quality primary pharmaceutical product: olive oil with a polyphenol content of 10/20 times the average, water vegetation concentrated in polyphenols, waxes for cosmetics. In the next step is possible, in addition to ultra filtration to concentrate the waste water in polyphenols, extracted from leaves collected from the annual pruning of olive other polyphenols (eg oleuropein antioxidant) and work the exhausted matrix to produce health food (the latter processing is facilitated by the absence of water vegetation on the previous stage supercritical extraction). Another advantage given by the supercritical phase process in the oil production chain is the complete absence of vegetation waste water that, in traditional processes, pollute heavily the soil (in Italy the wastewater requires special disposal and is a considerable monetary cost).
- Only in final processes for specialized applications (eg pesticide: pyrethrum and neem). This is the case of dealcoholization of alcoholic beverages, pasteurization of fruit juices and drinks in general, powder coating of the drug, oil and liquids fractionation, concentration of active ingredients or the recovery of waste materials from previous processes.
2) flexibility offered by SCF technology that can act on a wide range of process conditions and performs various processing stages (also in sequence). This quality can be used both in the extraction and fractionation process, getting new productions and products. Examples include: de-oiled meal, numerous extracts in co-extraction, extractions made in sequence (in a first phase apolar soluble compounds are extracted and sequentially in a second phase polar soluble compounds are extracted).
3) cost: in the beginning this technological approach could not offer many economies as the technology did not confer special benefits to the process. With the technological growth you can see the benefits of multi-purpose approach and the significantly improved production capacity. Furthermore, with the restriction in the use of organic solvents results from the EC, this technology shown its ability to bind to the quality of production even more economic efficiency. Technical factors that determine the SCF system cost are:
- extractions in sequence and in two phases with advantages in terms of time (significant is the saving of labour time and equipment given by the process of extraction of polar and non-polar)
- full use of raw materials because the supercritical plants produce more product at the same time
- reduced process time and high productivity achieved in extraction, separation and pasteurization, associated with the ability to completely remove the substance in question (oil or other compound)
- low cost of CO2
- savings in disposal costs necessary with traditional technologies
- low numbers of workers
4) High production quality recognized by the whole market.
Consequences of the characteristics of SCF technology and its market position:
- recognized by the market as production of high quality and in some cases without competition (es. coffee decaffeinizzation, lycopene, olive oil with high content in polyphenols, extracted pesticides)
- inclusion in food platforms in both structural processes, conditioning entire supply chains, and processes to reach niche or unique products available only thanks to this technology (eg extraction of antibacterials for high efficiency demonstrated, removal of pesticides, dealcoholization with retention of original flavours, pasteurization of liquid at low temperature, extraction of compounds that are particularly active in anti-cancer therapies such as lycopene and CBD cannabis)
- insertion, at the present time, in higher-end market for the following reasons: a) barriers (now removed in EC) against and prevention of environmentally friendly technologies and that are in opposition to the use of organic solvents (hexane) b) non-recognition of costs which are the hidden environmental costs for disposal of toxic substances and lack of attention or lack of prevention in productive activities in respect of use of toxic substances (eg, hexane, etc…)
- economy (already defined above) through:
- multipurpose system and technological developments that on one hand have significantly improved the efficiency and productivity (continuous separation systems that leverage new enthalpy of the process and structured packing, can be removed in a series of water-soluble and fat-soluble compounds, techniques of co extraction possible due to the wide range of process conditions offered by the technology, continuous pasteurization at low temperatures) on the other hand have reduced the environmental costs (low cost of the “solvent” supercritical CO 2),
- low workers number related with the investment,
- encouraging the use of clean technologies and the significant limitations to the use of organic solvents (hexane).