Design of a cosmetic formulation with a deep eutectic system coffee extract

• Main Author: Costa, Ana Carolina Ramos da
• Publication Date: 2022
• Format: Master thesis
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: http://hdl.handle.net/10362/153066
• topic: Spent coffee grounds; Deep eutectic solvents; Extraction; Phenolic Compounds; Topical formulation; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Over the world approximately are produced 6 million tons per year of spent coffee grounds (SCG). These are a valuable resource of bioactive compounds, such as antioxidant phenolic compounds, which makes them potential ingredients in topical formulations. One of the big- gest problems in the cosmetic industry is the large quantities of conventional organic solvents used. A green sustainable alternative is using Deep Eutectic Systems (DES). This work aims to valorize SCG extracts, by optimizing the extraction process of phenolic compounds with anti- oxidant activity, using natural DES to be incorporated directly in novel and sustainable Eco Label topical formulations. Several DES were produced and evaluated for the green extraction of the bioactive compounds from SCG. Extracts were assessed for total phenolic content (TPC), antioxidant activity (AA), in vitro ROS scavenging activity, cytotoxicity assays in human keratinocyte HaCaT cells, and stability over time. The optimal extraction conditions were stir- ring at 50ºC, for 1h and a solid/liquid ratio 1:10 (g/ml). DES with acids in their composition were toxic against HaCaT cells, while the remaining DES showed low cytotoxicity. An optimal extract was obtained with a DES composed of Proline: Glycerol: Water, which had higher TPC (16.72 mg GAE/g SCG), high AA (EC50 =0.20 g/mL), high capacity to reduce ROS (> 75%), abil- ity to inhibit HNE activity, and demonstrated stability upon a time, than conventional hy- droalcoholic extraction. Oil-in-water (O/W) emulsions were developed according to the Eco- Label regulation. After preparation, emulsions were characterized for their organoleptic, physicochemical, rheological, and spreadability properties. With this work, it was possible to develop emulsions suitable for topical application containing SCG extracts, compatible with the skin and with biological properties. SCG extracts prepared with DES, namely the optimal DES extract, have valuable properties that benefit their upcycling in the cosmetic industry.