During ultrasound processing of lipid-containing food, some off-flavors can be detected, which can incite depreciation by consumers. The impacts of ultrasound treatment on sunflower oil using two different ultrasound horns (titanium and pyrex) were evaluated. An electron paramagnetic resonance study was performed to identify and quantify the formed radicals, along with the assessment of classical physicochemical parameters such as peroxide value, acid value, anisidine value, conjugated dienes, polar compounds, water content, polymer quantification, fatty acid composition, and volatiles profile. The study shows an increase of formed radicals in sonicated oils, as well as the modification of physicochemical parameters evidencing an oxidation of treated oils. The increasing demands of higher quality and quantity of products in the food industry brought attention to the use of ultrasound (US) as a food-processing technique of interest as a technological benefit and/or as a technique to alter product functionalities. This technique presents several advantages over conventional methods in terms of energy consumption, time, and higher throughput. Ultrasound methods are used in the food industry for numerous processes on high lipid containing food products such as milk, yogurt, and cheese, presenting great results in cooking, cutting, emulsification/homogenization, and microbial inactivation. Interest in applying ultrasound methods in food processing lies in the fact that power ultrasounds are able to induce modifications (chemical, functional, physical, and structural, etc.) in some of food properties.