Olive Residues as a Source of Bioactive Compounds

The production of olive oils implies the generation of high quantities of solid residues and/or wastewater that may have a great impact on terrestrial and aquatic environments because of their phytotoxicity. Alperujo is a combination of liquid and solid waste from olive oil processing. Few studies are known that show their high biological potential. Indeed, wastes remaining after the production of olive oil are a heterogeneous mixture of many chemical components, such as metal ions, carbohydrates, and polyphenols, that may exert different biological activities, primarily acting as antioxidants. The samples of “alperujo” were obtained as waste from industries that work on olive oil production. Three ethanolic organic extracts were prepared using solvent maceration, ultrasound and reflux extraction methods. Yields of each extract were determined and evaluated for their ability to trap free radicals, using the DPPH and ABTS assays contributing to the calculation of SC50 (free radical scavenging). The extracts were subjected to preliminary phytochemical testing, analyzing phenolic content by the Folin method and heavy metal concentration using atomic absorption spectrometry. The extraction method was decisive for the yield obtained, with the reflux system being highly efficient, and the antioxidant activity shows the potential of these wastes as a source of bioactive compounds of interest for possible reuse.