S22 - Session P1 - Analyzing Global Dyes and Colorants: Specific plants, specific places - Towards the intensification of natural dyes extraction

Authors: Alix Gombert *, Christelle Harscoat-Schiavo, Christine Brunet, Arnaud Fertet, Pascale Subra-Paternault, Anne de la Sayette, Raphaëlle Savoire 40%). The objective of the work is to develop intensified processes which, in addition to reducing the volume of solvent used, can improve either the yield or the colour intensity of the extract. Two methods of eco-extraction are considered: supercritical-based technology (scCO 2 ) and the application of ultrasounds. Different plants will be considered as their coloring molecules are of different chemical nature (anthraquinones, flavonoids, anthocyanidins). Sc CO 2 being an apolar solvent, cosolvents will be used to favor the extraction of the selected molecules. In that case, the objective will be to optimize the process efficiency versus the solvent type and consumption. The first approach focuses on the use of ethanol-aqueous mixtures, as co-solvent for scCO 2 or as solvent for the application of ultrasounds. Investigations will be conducted using an experimental design approach and a statistical analysis of the responses to identify the key influencing factors and their interactions. For CO 2 -based process, the operating factors such as pressure (75-900 bar), temperature (40-120 °C), co-solvent percentage (0-20%), and CO 2 flow rate (20-100 g/min) will be varied to optimize at the same time the extraction yield and the color characteristics. Specific quantitation of molecular species will be also considered on selected extracts. Results will be compared to a reference hydro-alcoholic extract.