Wastewater from olive mills could prove a useful antioxidant source

French researchers have shown that the potent antioxidants found in the wastewater from mills that process olives could be extracted and used as a natural additive to pharmaceuticals or to extend the shelf-life of fresh foods.

Virgin olive oil contains several potent antioxidants. Known as olive phenols (OPs), these compounds can help prevent heart disease and some cancers. However, during the milling of olives, many of the OPs with a low molecular weight are discarded in the mill’s wastewater.

Claire Dufour and colleagues at the University of Avignon studied several of these OPs and believe they may be worth extracting from the wastewater. The team performed a series of experiments to find out how potent the antioxidants were and to better understand how they work.

Dufour found that, at concentrations similar to those found in the body, the activity of different OPs varied. While one of the compounds, a-tocopherol, was the best antioxidant for polyunsaturated fatty acids initially, olive o-diphenols had a more persistent effect. The concentrations of OPs in mill water are also significant. For example, the concentration of the OP hydroxytyrosol in the wastewater can be 100-fold higher than in the olive oil itself.

Shunichi Fukuzumi, professor at the department of material and life science, Osaka University, Japan, feels that the work by Dufour has a lot of potential but said that ’whether such a process is economically feasible or not has yet to be examined’.

Vikki Allen