Ultrasound-assisted extraction of bioactive compounds from olive pomace: Polyphenol content and antioxidant activity

Abstract With growing interest in sustainable solutions, olive pomace—a byproduct of olive oil production—has emerged as a source of bioactive compounds. This study investigates ultrasound-assisted extraction (UAE) as a green method for recovering antioxidant-rich polyphenols. A central composite design assessed the effects of extraction time (5–15 min), solid-to-solvent ratio (2–12 g per 100 mL), and ultrasound head size (small, medium, large) on total phenolic content (TPC) and antioxidant activity (AA). TPC ranged from 3.87 to 19.50 mg gallic acid equivalents per gram dry weight, while AA ranged from 3.31 to 11.15 mg ascorbic acid equivalents per gram dry weight. Solid-to-solvent ratio and head size had the strongest influence on TPC, with the large head at lower intensity producing the highest yield. The analysis revealed a positive link between TPC and AA ( r = 0.85, P < 0.001). UAE demonstrates efficiency and sustainability in valorizing olive pomace.