Olives and their production waste products as sources of bioactive compounds

A review. Olives are rich in phenolic antioxidants that, during olive oil prodn., end up either in olive oil or, for their major part, in the waste water. In fact, during the malaxation process, i.e. the continuous washing of the olive paste with warm water prior to the procedure of sepn. of the oil from the paste, a considerable amt. of water is employed. This water, in addn. to that endogenously contained in the olives, make up to 50% of the total yield of the olive paste (olive oil amts. to ∼15%) and is named "waste water". In fact, due to the failure to develop a suitable end-of-pipe treatment technol., olive mill waste waters (OMWW) are currently discarded by olive oil manufacturers. In vitro, phenolic components of olive oil and its waste water have been shown to exert potent biol. activities including, but not limited to, antioxidant actions. Catechols from olive mill waste water can be isolated in rather pure form: 10-20 per cent of the total phenols is recovered and the only bioactive catechol is hydroxytyrosol. This ortho-diphenol has been shown by several authors to exert potent antioxidant and addnl. biol. activities, both in vitro and in vivo.