Potential of alternative solvents to extract biologically active compounds from green coffee beans and its residue from the oil industry

Food waste causes great impact on society and the environment. Residues disposal is observed throughout the production chain, which establishes a need to use both food as a whole and the possibility of maintaining habitual consumption with the use of residues for new food products or in another industrial branch. In this perspective, this study aimed to evaluate the role of selected traditional organic solvents on the extraction of total soluble solids and bioactives from green coffee beans and its press meal as an alternative to make use of this waste generated by the oil industry. Six solvents with different polarities were used (acetone, ethanol, ethyl acetate, hexane, isopropanol, and petroleum ether) in order to evaluate the yield of soluble solids/oil and the bioactivity (Folin-Ciocalteau's method, DPPH, ABTS, FRAP, and beta-carotene bleaching assay - BCBA) of green coffee beans and its industrial press meal. The results showed that the tested solvents played an important role in the extraction of total solids and antioxidant capacity from the matrices analyzed. Ethanol was found to be the optimal extraction solvent for extractable solids from both green coffee beans and meal, as well as for the phenolic and antioxidant compounds. Only that, for BCBA analysis, ethyl acetate yielded the best results for the antioxidant activity of green beans and meal. Therefore, ethanol is recommended for the extraction of soluble solids, phenolic, and antioxidant compounds from green coffee beans and its press meal for further isolation and utilization. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.