Circular Valorizaron of Coffee Silverskin through Supercritical CO2 for Functional Extracts Production

The development of sustainable procedures for the valorization of industrial biomass wastes represents a major challenge for the scientific community. Among residual biomasses, coffee silverskin could represent an attractive source of bioactive compounds. In spite of promising applications, silverskin is still underutilized and nowadays still discarded by the roasters as solid waste in landfills. This work presents the application of a green unconventional extraction strategy, supercritical CO2, with a particular focus on the extractability of polar compounds from green coffee beans and their related wasted biomass, coffee silverskin, by means of the addition of ethanol as co-solvent, allowing to shift the window of extractables towards more polar molecules. Results point out the ability of the supercritical fluid to efficiently target chlorogenic acids, minimizing the excessive use of organic solvents and avoiding the presence of inorganic or organic acids. The use of a co-solvent, at the expense of reducing the selectivity towards target species, was demonstrated to efficiently co-extract other classes of compounds directly connected with the relevance of silverskin’s phytochemical profile, dealing mainly with its antioxidant and prebiotic properties, pointing to interesting applications in functional food products.