Ultrasound-assisted solvent-free extraction of rosemary absolute oil: A green paradigm for high-efficacy natural antioxidant in frying oil stabilization

What if the secret to healthier frying oil was hidden in a rosemary leaf—and could be unlocked without a single drop of chemical solvent?

Rosemary isn't just for roasted potatoes anymore. Scientists have developed a green extraction method that turns this humble herb into a powerhouse antioxidant for frying oils. Using ultrasound-assisted solvent-free extraction (UOE), they achieved a remarkable 19.09% yield of rosemary absolute oil (RAO) in just 13 minutes—no toxic solvents, just soybean oil and sound waves. The resulting oil was packed with bioactive compounds, including carnosic acid (89.45 mg/g) and ursolic acid (7.43 mg/g), giving it radical-scavenging power on par with synthetic BHT. When added to soybean oil at just 0.1%, UOE-RAO doubled the oil's frying life from 31 to 63 hours, dramatically slowing the buildup of harmful polar materials. Even better, the oil resisted oxidation longer under high heat, as confirmed by DSC analysis. This isn't just a lab curiosity—it's a practical, sustainable path toward cleaner frying and healthier food.

Key Points

• Ultrasound-assisted solvent-free extraction yields 19.09% rosemary oil in 13 min
• RAO matches BHT antioxidant activity (IC50 71.26 μg/mL)
• 0.1% RAO doubles frying oil life from 31 to 63 hours