A great deal of peel, pulp and stone waste is constantly being generated in the production of olive oil. And while that waste is often just dumped or incinerated, it could soon be used as a source of valuable antioxidants.
The extraction technique was developed by ETH Zurich mechanical engineering student Claudio Reinhard and Prof. Laura Nyström, the two of whom initiated the EU-funded Phenoliva research project in 2019. Spinoff company Gaia Tech is now commercializing the technology.
At the start of the process, olive waste and residual olive-processing wastewater are placed in a centrifuge.
That material then gets rapidly spun and separated into its solid and liquid components, the latter of which passes through an "absorber" which collects the antioxidants. That absorber is made of a 100% biodegradable proprietary substance that can be renewed and reused several times, before ultimately being utilized as fertilizer.
Upon being removed from the absorber, the viscous antioxidant extract is quite dark in color and bitter in taste. Several purification steps are thus required to make it more suitable for use in products such as skin-rejuvenating cosmetics or health food supplements.
Plans now call for Gaia Tech to trial the technology in a pilot project with an agricultural cooperative in the European microstate of San Marino. If that project is a success, Reinhard and partners may look into applying the technology to other types of agricultural waste, such as that generated in the production of coffee and cocoa.
"I wanted to find a way to reuse agricultural waste in support of a sustainable circular economy," said Reinhard. "One bottle of olive oil generates waste equivalent to the amount of four bottles."
And as an interesting side note, scientists at France's Mulhouse Institute of Materials Science have already devised a process for converting olive mill wastewater into biofuel, fertilizer and clean water.
Sources: ETH Zurich, Gaia Tech