The new study Extraction of Antioxidant Phenolic Extracts from the Two Main Liquid Effluents of the Olive Industry
recently published on Foods suggests that some of the olive industry’s most problematic waste streams could become valuable sources of functional ingredients. Researchers developed a process combining thermo-malaxation, centrifugation, and industrial chromatography to recover bioactive phenolic compounds from olive oil by-products and table olive brines. The extracted fraction was particularly rich in hydroxytyrosol, tyrosol, and 3,4-dihydroxyphenylglycol, compounds widely recognized for their antioxidant properties. In vitro tests confirmed the high antioxidant activity of the recovered extracts, highlighting their potential use in nutraceuticals, functional foods, and health-promoting formulations. Beyond creating new ingredient opportunities, the approach also helps reduce the environmental burden associated with olive industry effluents, supporting a more circular and sustainable agri-food value chain.
As Spain, the world’s leading olive oil producer and one of the largest table olive producers, continues to expand its olive sector, the management of by-products such as alperujo and fermentation brines is becoming an increasingly pressing sustainability challenge. Traditionally regarded as difficult-to-manage waste streams due to their high organic load, salinity, and phytotoxicity, these effluents are now gaining attention as valuable reservoirs of bioactive compounds.
In this study, researchers demonstrated that a combination of thermo-malaxation, three-phase centrifugation, and industrial chromatography can efficiently recover phenolic compounds from both olive oil and table olive processing by-products. The process concentrated key olive phenolics, including hydroxytyrosol (HT), 3,4-dihydroxyphenylglycol (DHPG), and tyrosol (Ty), while simultaneously reducing the toxicity of the remaining effluents. Chromatographic treatment removed between 50% and 75% of the phenolic load, with hydroxytyrosol reductions reaching more than 80% in some streams.
The recovered extracts showed remarkable antioxidant activity, outperforming comparable olive-derived extracts in several in vitro assays. Hydroxytyrosol, one of the most studied olive phenolics, has been associated with antioxidant, anti-inflammatory, anti-atherogenic, and skin-photoprotective properties, while DHPG has demonstrated antioxidant capacity that may exceed that of both hydroxytyrosol and vitamin C under certain conditions. Beyond their antioxidant potential, these phenolics have been linked to antimicrobial, antiproliferative, immunomodulatory, and healthy-aging benefits, making them attractive candidates for functional foods, nutraceuticals, and beauty-from-within formulations.
The findings support the growing biorefinery approach in the olive sector, where waste streams are first valorized through the recovery of high-value bioactives before undergoing additional biological processes. By transforming problematic effluents into sources of natural antioxidant ingredients, the strategy not only improves environmental sustainability but also creates new opportunities for the development of next-generation functional products and the replacement of synthetic antioxidants.
