Review of deep eutectic systems from laboratory to industry, taking the application in the cosmetics industry as an example

Green and sustainable chemistry principles have been employed in different industries to create greener and safer chemicals and processes, by replacing hazardous solvents with safer and more efficient ones. A state-of-the-art analysis on deep eutectic systems (DES) shows their consistent growth in the fields of chemistry, particularly as extraction solvents, mainly of bioactive compounds from natural sources. In this sense, a patent review was carried out, to highlight the relevance of DES, formed by natural compounds, in the cosmetic industry and the commercial added value of this technology at the industrial scale. Despite their good extraction efficiency, DES physicochemical properties need to be considered, as they may present some limitations in the process scale-up. This implies the study of several parameters, such as the cost of raw materials, the investment necessary to adapt or implement new equipment, energy consumption (for instance for pumping, heating, and stirring), and treatment of any by-products and wastes, in both the upstream and the downstream operations. Due to their inherent properties, DES can also be used as stabilizing agents of the bioactive compounds extracted, allowing their direct use in final products, namely in cosmetics, which is translated into a reduction of the downstream costs. This work further reports a case study of the extraction of grape anthocyanins with DES, and the necessary steps required to take this process from a laboratory scale to an industrial scale, targeting the cosmetic industry.