FAIR-CT97-3464 DASFAF Network: Developments and applications in supercritical fluids in agriculture and fisheries

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Website: www.dasfaf.org
Summary Information



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Agriculture : FAIR Area 1.2 - Green Chemicals and Polymers Chain : Fine Chemicals : Process Engineering

	Contract No:	FAIR-CT97-3464
	Date Prepared:	June 2001, October 2000, October 1999
	Source:	Final Report Second Annual Progress Report First Annual Progress Report

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Final Report Abstract & Executive Summary

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Second Annual Progress Report Abstract

Note: In March 2000 the composition of the group was changed. The University of Antwerp and its industrial partner, N.V Cargill, withdrew. The following organisations joined the project: Hitex, France; Archimex France and Gaiker, Spain.

Objectives

During the second project period, the main objectives were to encourage collaborations between partners, expand on future work, dissemination of the Network, and improve the Network web-site. The ideas and knowledge exchanged between partners during the second meeting (as a result of the first project period) resulted in collaborations and projects during this second period, as well as the third meeting, held as expected. In this third meeting, interviews between partners of mutual interest were planned and as results of them several proposals for future work between partners were planned. Subjects of mutual interest for the partners that were selected during the second meeting have been also discussed and a methodology to approach new proposals was developed. As in previous meetings, the partners had the opportunity review of their research activities during the period, with the various presentations edited into a proceedings volume.

Activities

These mainly concerned promotion of the Network, increased knowledge exchange between partners through use of the DASFAF website and holding the third meeting. In addition the Network partners are preparing a state of the art book with the aim of providing an overview of the actual and future trends in Supercritical Fluids research and its applications. The Internet site created during the first period has been improved. Now the site has its own domain (http://www.dasfaf.org). A part from the initial sections which include a database covering aspects concerning industrial plants located around Europe, as well as research organisations working with SF technology, new sections have been created in the form of an Industrial Advertisement Board, and a discussion forum for all kind of users. In the forum, questions and suggestions can be put forward, resolved and discussed between users and partners covering various aspects of the technology.

Progress

During the second year collaboration and formation of projects between the partners continued, while new contacts with international research groups working on with this technology have been initiated, and will in the future be extended. As a result of this interest, some individuals, who were not members of the Network were invited to attend the third meeting.

Achievements

During this period the third meeting of the network was held, the state of the art book prepared and the improvements on the Internet page made. The third meeting was held at DICAMP (Trieste, Italy) in June of 2000 where 28 participants met to present an overview of their activities and further collaborations planned. A presentation of the web site improvements was made, and new suggestions were considered to improve its function. The final scheduling for the state of the art book preparation was presented. The proceedings of the meeting will be edited and distributed to Network members.

Future actions

During the third meeting, new ideas for future collaborations and suggestions to prepare proposals to submit to the V Frame Work Programme were made. At the time the report was written partners were working in the State of the Art book, and an Information leaflet about the Network was being edited. With a year left before the project ends, the most important action to is to decide the future of the DASFAF site. During the third meeting some ideas were made, such as for example, to set-up an international public Network co-ordinated in each participating country by the DASFAF members. This was to be discussed over the next few months.

Scientific synthesis

Introduction

The DASFAF (Developments and Applications of Supercritical Fluids in Agriculture and Fisheries) network aims to enhance current knowledge of supercritical fluids (SF) in the food sector and related industries. The main objectives of the network are:

• to promote this technology in universities, research centres and enterprises working in this sector, and make it known to small and medium size companies.
• to evaluate both immediate and future applications, transfer acquired knowledge and detect or show current problems faced by small and medium size companies, with a view to finding future solutions through collaboration between research centres and companies.
• to set up long-term projects, increasing companies' co-operation and participation both nationally and internationally.

The co-ordinated action focuses on the following areas:

Basic principles of SF, including aspects of:

• Phase equilibrium
• Estimation and determination of diffusivity, transfer coefficients of matter, energy, etc.
• Creating a model of the thermodynamic behaviour of mixtures in a supercritical state
• Creating a model for the kinetics of extraction, reaction, etc.

Extractive applications of SF , This section includes the tasks concerning

• Acquisition of active products for pharmacological use
• Removal of alcohol from beverages such as beer, wine and liquors
• Purification and fractionation of polymers, removal of solvent residues present in plastics, elimination of monomers, oligomers, etc.
• Extraction of colouring, aromas, antioxidants, fats, pesticides, etc.
• Analytical extraction.
• Characterisation of the extracts obtained: developments of analytical methods, stability of extracts, microbiological activity, biological activity, etc.

Non extractive applications of SF Some examples of these new, different applications are:

• Chromatography on an analytical scale, semi-preparatory and preparatory
• Food hygiene: On one hand, the sterilisation of yeast, bacteria, enzymes, etc eliminating the high-temperature stages and reducing energy costs, and also avoiding the possible degradation of thermolabile compounds (vitamins, aromas, etc.). On the other hand, the elimination of insects (larvae and eggs) which damage foods (moths, maggots, etc.) by rupturing the cells as a consequence of rapid de-pressurisation. In this It way, it is possible to stop using methyl bromide or other dangerous solvents in the food It industry, a positive step towards the conservation of the ozone layer.
• Volumetric expansion of vegetable matter, as is produced with tobacco, spices, rice and infusions, improving both "filling" capacity and porosity.
• Micronisation of chemical substances which is interesting from a pharmacological and phyto-sanitary view, as well as in the field of plastics, etc. achieving higher quality and more uniform products by means of rapid expansion of supercritical solutions (RESS), anti solvent gas effect (GAS), etc.
• Reactions such as enzymatic esterification, achieving greater selectivity.
• Higher reaction speed, lower energy costs as a consequence of the lower temperatures, absence of dangerous, toxic organic solvents. Moreover, one will be able to obtain products that can not be obtained through enzymatic chemical reactions.
• Impregnation of different substances (colouring, perfume, pesticides, antioxidants, medicines) in polymers, ceramics, etc. using SF as transmission vectors.

Industrial aspects In this section, we include landmarks that are of great interest in terms of industrial SF 7 application such as:

• Optimum separation conditions.
• Development of continuous processes: solid and liquid foods.
• Development of cleaning teams and systems.
• Economic aspects of commercial installations.
• Systems for regeneration of SF after extraction by means of changes in pressure, temperature, absorption, adsorption, membranes, etc.
• New, improved units: development of pumps, autoclave closure systems, extractors for continuous treatment of solids, etc.
• Linking SFE up with other separation techniques.
• Automation of small and large, extractive and non-extractive installations.
• Ecological processes to obtain usable solvents such as SF.

Activities

Discussion concerning operational and application aspects of this technology between various research groups and agro-food companies have enabled the development of strategies to increase uses of supercritical fluids , as well as improving current procedures. These new strategies will aim to indicate the wide potential benefits that the technology offers to SMEs, using specific examples where the consequent economic development can be seen by companies working in various areas, including primary production, manufacturing and service, all of whom are represented in this network.

As a result of the first meeting technological advances made in the different areas have been reported and detailed in the proceedings. During each session of the first meeting, dedicated to the four areas of the project, the research activity of each organisation and future perspectives were discussed. As a result a number of conclusions were and conclusions were reached in each area, as summarised below:

Area 1: basic principles of SF

Theoretical bases of SF technology is required to reduce experimental costs and so optimise SF plants because progress made in these areas can be used to simulate predictive models. Better knowledge of the fundamental properties of the mixtures involved is a basic requirement for describing and understanding processes and for optimising their performance. A detailed knowledge is important to transfer this technology to SME working in the agro-food sector or similar, and to convince them that new processes based on SF may, where appropriate, advantageously replace classical processes of separation, refining or purification.

Activities The research activity described in this first session fell mainly in the following areas:

• Phase Equilibrium Measurement and Modelling.
• Mass-Transfer Modelling for Extraction, mainly from solid materials, but also from liquids.
• Recovery of samples extracted for analytical purpose

Subject 1 is strongly represented in the DASFAF Network, in terms of both experimental and in theoretical aspects. Several groups have developed models in subject 2. More information on this subject will be given in the discussion on Extractive Applications.

Perspectives and Project Proposals: Measurement of phase equilibrium data for multi-component systems of interest for applications is the most needed future development. Several groups in the DASFAF Network have the intention of carrying out this type of measurements. Modelling methods with a good predictive capability have been difficult to develop. In the near future, these methods will require some experimental data to fit adjustable parameters. The reliable calculation of gas-liquid critical properties and of the sublimation pressures of many substances is also badly needed. The fundamentals of mass transfer into a supercritical fluid-rich phase are beginning to be better understood. Several groups in the Network have reported work on models that can help to solve design problems for future applications. Projects in food preparation for animals or for edible diet purposes were suggested.

Area II: non extractive applications of SF

Over the last 25 years SF use and technology have developed quickly and become widespread, and although at the beginning the technology were focused on extractive applications (due to the successful results obtained in this area), nowadays non- extractive applications are taking more a more importance role within the scientific community thanks to the physical-chemical characteristics of SF.

Activities

Partner 2 made a survey of the field and identified 6 areas comprising chromatography, fractionation, polymer processing, particle formation, coating paintings and dyeing, and reactions. Partner 3 discussed analytical SFC especially lipid class characterisation fatty acid separation from triglycerides and their removal and catalytic reactions.

Partner 5 discussed scale up procedures including SMB (Simulating moving bed) applied to fish oil. Also, membrane separation was compared with separation without using membrane.

Partner 8 discussed phase equilibria in SFE and chiral separation using SFC.

Partner 9 discussed the determination of skatol and lipid classes using packed column SFC. '4 > Partner 10 discussed gas-antisolvent micronisation, and extrusion with carbon dioxide.

Partner 11 discussed making of micron-particles, aerogel drying by substitution of organic solvents with C0₂, cleaning of surfaces and decontamination- sterilisation procedures.

Partner 12 worked in the following areas: RESS (Rapid Expansion of Supercritical Solvents), GAS to particle reactions, supercritical antisolvent (SAS), and polymer processing and regeneration. Partner 21 works with controlled release of drugs solvent removal from pharmaceutical products, polymer impregnation of drugs and partial production of steroids.

Co-ordinator (AINIA) discussed crystallisation and precipitation of flavonoids from grape skin, and elimination of microbiological and biological contamination.

Perspectives and Project Proposals:

Reactions with water and enzymatic reactions in carbon dioxide.

Synthetic reactions in analytical scale (derivatisation) and in large scale processes.

Chiral separation using SFC.

Pilot plant procedures for impregnation and solvent removal.

Determination of lipid classes using SFC.

Introduction of fat-soluble additives, e.g. aroma compounds and vitamins, to extruded materials. To utilise wastes from fish product production.

Application of SFE for purification of natural products of high value as antioxidants, colourings, etc.

AREA III: industrial aspects

SF technology implies the use of high pressure, so industrial equipment must be designed determining optimum operative conditions, with most suitable materials and adequate safety systems. As more is known about the scale-up of SF processes, it is more easy to introduce this technology into small and medium size companies thanks to advantages made in this area. Research activity:

• Liquid-fluid fractionations: aromas, fish-oil, polymers, depollutions,
• SF and extrusion: polymers, food.
• Different applications/activities that were mentioned included:
• Production of dyes from plant material
• Modification of fibres
• Utilisation of organic waste
• Extraction of oil from fish muscle
• Fractionation of fish-oil
• Fractionation of polymers/lubricants

Perspectives and Project Proposals:

Removal of Organic residues/solvents or Pollutants (pesticides).

Utilisation of residuals from processing of edible oils.

As projects proposals it was discussed about:

Extraction of natural antioxidants

New polymers for package

Area IV: Extractive applications of SF

Extractive applications of SF are well developed and widely uses in food, pharmaceutical and cosmetic industries. In these fields such applications have good prospect due to consumers' interest in products that are free from organic solvents, and the tendency of use natural sources as an alternative to synthesised products. Potential uses of SFE are increasing and new possibilities opening up. Research activities presented by the laboratories of most of the participants related to this area. The following aspects have been presented:

an overview on the different extraction units at the laboratory, beginning with PE (Phase Equlibria) apparatus, passing our solid SFE micro-plants, continues counter-current extraction units and a new mixer settler unit.

• the design of separation columns
• applications in raffination of olive oils, and the separation of wines aromas
• two equipment units, one for sample preparation for the measurement of solid solubility in SF, and another SFE (bench scale unit)
• an extraction column with mechanically agitated mixing plates, the length is about 2 metres, i.d about 42 mm.
• a batch extraction plant for grape seed oil.
• comparison of SFE and SBE on the fatty acid composition of products, mainly in respect of the steroid androsterone.
• various semi-industrial plants for flower concretes fractionation, and essential oils extraction.
• presented the results of an existing EU-co-operation that aimed to reduce the loss of vitamins. neutraceuticals and marginal crops, post harvest process optimisation
• aromatic and medical plants
• modelling of the SFE of natural products

Perspectives and Project Proposals: The participants concluded that there was a high potential for future co-operations in areas such as exchange of experience in fatty acids production, lipid production and biotechnological products. A special interest relates to the elimination of DDT and PCB in agro-food products, also on the elimination of organic solvents in a subsequent separation step following on from a classical treatment unit. The participants agreed that attention must be paid to some residues of the products like ethanol that remained in the counter-current systems. The choice of trap units must be optimised.

Conclusion

The DASFAF Network has several groups that can solve problems, including obtaining experimental data or developing modelling methods in phase equilibrium, mass-transfer and recovery of extracts for analytical purposes. It was suggested that these capabilities could be used in projects where supercritical fluids technology is combined with other types of technology. One important objective should be to obtain representative physical data (ex: viscosity reductions in polymer solutions of C0₂). This could be used for preliminary feasibility studies of proposed industrial applications.

The development of language and communication tools for better contacts with industrialists was suggested. Most of the work on non-extractive applications has so far been done in the fields of chromatography and crystallisation of small particles down to sub micron size. However, several participants expressed the view that field of reactions in supercritical fluids should be further investigated, especially enzymatic reactions in supercritical carbon dioxide.

Preparative SFC might become a very interesting technique for valuable compounds offering, in comparison to HPLC, a faster sample throughput.

Use of Supercritical Fluids in industrial applications is feasible when utilising high-value products.

Use of Supercritical Fluids in industrial applications should be taken into consideration when:

• No other method is suitable.
• Use of SF produces a unique product.
• The demand for solvent residue is zero.

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First Annual Progress Report Abstract

Objectives

During the first period of the DASFAF discussion between various research groups and enterprises were initiated concerning the operation and application of supercritical fluid (SF) systems. The overall aim is to develop strategies that will increase the possibilities for use of such techniques in various agro-industrial sectors, as well as improving current procedures. Through several meetings and knowledge exchanged several proposals for future work between partners were planned.

Activities

These were focused, in the first period, mainly on knowledge exchange aimed at fostering future collaborations. An Internet site has been created with a database covering aspects of relevance to industrial plants located around Europe, as well as research organisations working with SF technology. This includes a discussion forum, where questions and suggestions can be put forward, resolved and discussed.

Progress

During the first year the activities confirmed the interest of the partners towards future collaborations and establishment of projects is noticed between the partners, while new contacts with international research groups working on with this technology have been initiated.

Achievements

The main achievements in this first period are holding of the first and second meetings of the network and the creation of an Internet page, as indicated above. The first meeting was held at AINIA (Valencia, Spain) in October 1998 where more than 28 partners met. During this first meeting four areas were included, for each of which an introductory lecture was presented by a relevant specialist, followed by reports covering the participants varied experience with SF technology. The proceedings of the meeting were edited. During the meeting a Consultancy Commission was created. This includes eleven prominent scientists from both University/Research Institute and industry. The second meeting was held at Vannes (France) during May 1999 where more than 25 partners met. During this meeting an overview of the research line of each partner was presented and meetings between partners of mutual interest were planned. A review of the web site structure was carried out, and suggestions for improvements were considered. Again proceedings of the meeting were produced.

Future actions

It was intended to hold the 3rd meeting, in Trieste (Italy, End of May, 2000), where different projects between participants in the Network will be established and organised, knowledge and approaches will be realised and new ideas and contacts will be promoted. Other future actions are to extend the data base of the web site and to bring up to date existing information.