Ultrasound-assisted extraction of water-soluble components from olive stones: Chemical characterization and...

This study explores the potential of ultrasonication as an efficient and sustainable technology to improve the extraction of water-soluble components from olive stones (OS), a by-product of the olive industry. OS were milled into powder (OSP), and aqueous suspensions were treated with ultrasound for increasing times. The resulting aqueous extracts (US-AE) were analyzed for chemical, physicochemical, and functional properties. Increasing ultrasonication time enhanced the phenolic content (from 247.5 ± 1.0 to 367.3 ± 0.7 mg GAE/g_dw) and promoted the release of high-molecular-weight (> 100,001 Da) compounds (from 7.05 ± 0.49 to 11.82 ± 0.11 %) derived from the disruption of the lignocellulosic material. US-AE exhibited remarkable antioxidant activity (DPPH, FRAP), antimicrobial capacity against pathogens and spoilage microorganisms, and the ability to produce stable emulsions for up to 30 days, while exhibiting no cytotoxicity. This research demonstrated the feasibility of ultrasonication in obtaining novel ingredients from OS, within a circular economy framework.