Hydroxytyrosol recovery from olive pomace: a simple process using olive mill industrial equipment and membrane technology

In this work, pilot-scale nanofiltration was used to obtain aqueous solutions rich in hydroxytyrosol and tyrosol from olive oil by-products. A large-scale simple process involving olive mill standard machinery (blender and decanter) was used for the olive pomace pre-treatment with water. The aqueous extract was then directly fed to a nanofiltration unit and concentrated by reverse osmosis. Final concentration factors ranged between 7 and 9 for hydroxytyrosol and between 4 and 7 for tyrosol. The final aqueous solution, obtained as retentate stream of reverse osmosis, was highly concentrated in hydroxytyrosol and tyrosol and their concentrations remained stable over at least 14 months.

Automated summary

This study utilized pilot-scale nanofiltration to extract aqueous solutions rich in hydroxytyrosol and tyrosol from olive oil by-products. A large-scale simple process was employed for pre-treating olive pomace with water, followed by direct feed to a nanofiltration unit and concentration by reverse osmosis. The resulting aqueous solution, obtained as the retentate stream, exhibited high and stable concentrations of hydroxytyrosol and tyrosol for at least 14 months.