Antioxidant activity of olive oil mill wastewater obtained from different thermal treatments

In food industry, Olive Oil Mill Wastewater (OOMWW) is considered a by-product because of the presence of biostatic compounds with a high polluting rate, in particular phenols. Moreover, during olive oil processing, a large amount of this by-product constitutes an ecological and economical problem for the producers. To reevaluate this by-product, the reuse of this wastewater to obtain useful compounds appears to be very important. In order to purify the wastewater, the development of operations that modify its organic content seems necessary for obtaining of eventual fertilizing agents and/or to recover substances with a high added value such as phenolic compounds, which are currently recognized scientifically as molecules with a high antioxidant activity. A chromatographic analysis of these compounds was conducted to characterize different concentrations of wastewater and the reducing power of the extracts was measured. The thermal treatment of olive oil mill wastewater in a rotary evaporator and in an oven involved an increase in radical scavenging efficiency. These results could be correlated with the possibility of recovering and reusing this type of waste for its antioxidant properties.