Solvent-free microwave extraction of natural products
- How does it work?
- What can it be used for?
- What can it not be used for?
- Related Facilities
- Further Information
|Key words||Microwave, hydrodiffusion, extraction, solvent-free, essential oils, antioxidants, colours|
|Completed by||INRA - IATE|
How does it work?
|Primary objective|| Solvent-free extraction of metabolites from fresh plants (fruits, vegetables, herbs, spices...)
The same principle is used for Microwave drying of spice and herbs
|Working principle|| This extraction method is performed by Microwave heating at atmospheric pressure.
The plant material, without any added solvent or water, is placed in a batch (= extraction vessel) inside the microwave oven. The internal heating of the in-situ water distends the plant cells and leads to the rupture of glands and oleiferous receptacles. The physical phenomenon, known as hydrodiffusion, allows the extract to diffuse outside the plant material. The solution is continuously cooled through a cooling system outside the microwave oven. Oils and water are separated by decantation. The excess of water is refluxed back to the extraction vessel in order to restore the in-situ water to the sample (1). For an equivalent amount of material to process, the solvent-free microwave extraction requires much less time than traditional processes. Examples: Basil, garden mint, thyme essential oils: 30 min. of extraction vs. 270 min respectively, with equivalent yields (2). Orange peels essential oils: 10 min vs. 180 min, with equivalent yield and non-oxygenated compounds amount, and a 78% rise for oxygenated compounds amount (3).
picture: 100 litre microwave extractor
|Additional effects|| This process can produce essential oils in concentrated form, free from any residual solvents, contaminants, or artefacts.
The extracted essential oils can be analyzed directly by GC-MS without any preliminary clean-up or solvent exchange steps (4).
|Important process parameters|| Duration
|Important product parameters|| Water content of the initial product
Polarity of the compound of interest
What can it be used for?
|Products|| Extracts coming from: aromatic herbs, spices, dry seeds (4)
Juice, essential oils, colours, antioxidants (2)
|Solutions for short comings||Search for green extraction processes|
What can it NOT be used for?
|Products||Only plant-based products, no petroleum solvents|
|Operations||Only extraction or distillation, no synthesis or drying|
|Other limitations||Capacity: from 5 litres to 100 litres|
|Risks or hazards||Related to the elevated temperature (up to 100°C).|
|Maturity|| The method and device are patented for the European territory.
A 100 litre pilot experimental device is available by April 2012 at INRA - SQPOV (Avignon, France).
|Modularity /Implementation||This technology replaces the existing extraction equipment.|
|Consumer aspects|| No specific study has been carried out so far regarding consumer acceptance.
Yet there is a general trend for more natural products and eco-friendly processes.
|Legal aspects|| European Patent, EP 1 955 749 A1, 2008.
United States Patent, US 2010/0062121, 2010. International Patent PCT, WO 089943 A1, 2008.
|Environmental aspects|| Absence of solvent
Energy savings due to the short extraction time
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|Institutes||INRA - SQPOV, Université d'Avignon et des Pays de Vaucluse|
Duration Powerwarning.png"Duration Power" cannot be used as a page name in this wiki. Water content of the initial product Polarity of the compound of interestwarning.png"Water content of the initial product Polarity of the compound of interest" cannot be used as a page name in this wiki. Heaters 2.2.1 physical separation other Interview with researchers from the Safety and Quality of Products of Plant Origin research unit (SQPOV, INRA Avignon, France): Farid Chemat, Catherine Renard, Christophe Nguyen-The WikiSysop :Template:Review document :Template:Review status