Impact of natural deep eutectic solvents-based microalgae extracts on the stability and properties of skincare products
Résumé
Background : Natural deep eutectic solvents (NaDES) are green ionic liquids prepared by mixing vegetal cellular constituent and metabolites such as sugars, polyols, aminoacids or organic acids. Their specific hydrogen-bond network confers high dissolution power combined with stabilizing ability, which make NaDES perfect media for sustainable valorization of vegetal biomasses. Their composition makes the resulting extracts truly biocompatible and then the solvent removal step in extraction processes becomes superfluous. Methods: Our consortium worked on the formulability of a range of 20 hydrophobic and hydrophilic NaDES, compliant to European and Chinese cosmetic regulation. A part of this work, concerning the formulability of a hydrophilic NaDES, will be described in this article. Typical situations will be illustrated through examples of an Arthrospira platensis microalgal extract. The products modifications in terms of organoleptic properties, stability, rheology and sensory properties will be evaluated. Results: Gly:Glu (1:2, mol/mol) NaDES was considered for formulation. Sensory analysis of NaDES permitted to attest that it had appropriate properties to be included in a cosmetic product. This NaDES was included in a basic cosmetic gel at concentrations from 1% to 10%. This study indicates that this NaDES could be used to prepare bio-based ingredients that can be introduced up to 10% in gels. Moreover, the introduction of this specific NaDES spirulina extracts have a positive impact on the color and the stability of antioxidant molecules and pigments, notably carotenoids and phycocyanin. Conclusion: The results of this study are in favour of the development of the exploration of NaDES as sustainable cosmetic ingredients.