Valorization of Olive Processing By-Products: Characterization, Investigation of Chemico-Biological Activities and Identification of Active Compounds

The valorization of food processing by-products, wastes and effluents is a challenging opportunity for the sustainable and competitive development of several relevant industrial sectors. One of the best examples of a biorefinery applied to plant processing wastes is that of the olive oil sector by-products including leaves and olive mill wastewaters (OMW). Management of OMW, in particular, has received much attention over recent years including all possible strategies, i.e. treatment, disposal, recovery and reuse. Besides being a serious environmental problem, OMW can also represent a precious resource of potentially valuable molecules. This later approach appears to be the new frontier in olive processing by-products valorization. The present paper will review the scientific works done in our laboratory concerning the valorization of olive processing by-products mainly OMW and olive leaves through the recovery of valuable molecules. Analytical chemical techniques such as solvent extractions and characterization of extracts in respect with their phenolic content were performed. Different methods were also used to investigate the activities of different extracts and fractions. Therefore, the antioxidant assays using DPPH (1,1'-diphenyl-2-picrylhydrazyl), beta-carotene, ABTS (2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid)) and bioassays including anti-tumoral activity, and in vivo activities in animal models were carried out. Besides, analytical chromatography and spectroscopic techniques were used by our group either for a deep characterization of active fractions or for the identification of new