Power ultrasound is applied in food technology to intensify extraction processes, due to the phenomena ultrasonic energy induces in the medium, enhancing mass transfer. The purpose of this work was the acoustic characterization of four transducers of different geometries and the evaluation of their performance in the ultrasonically assisted supercritical fluid extraction of antioxidants from oregano. The transducers differed in the amount of energy transmitted into the medium. Designs varied from the base model (T1), a larger cylindrical headmass (T2), a stepped circular section sonotrode (T3) and a multiplate configuration (T4). The highest nominal power density provided according to the calorimetric method was for T4 (151.6±7.1 W/L). The T2 produced a more uniform acoustic field and a higher acoustic pressure (150.6±20.5 kPa). Both parameters had an impact on total phenolics and antioxidants extraction with CO₂ under supercritical conditions (35 MPa, 35 °C, 2.3% ethanol as co-solvent). T4 and T2 were equally efficient (4.0±0.2 and 4.2±0.2 mg GA/g) for phenolic extraction, and with respect to antioxidant capacity, the best performance was that of T4 (26.4±1.1 μmol TE/g). Of the antioxidant compounds extracted, flavones and flavanones were identified. Therefore, transducer geometry influenced the amount and distribution of energy transmitted into the medium, thus determining the efficiency of the extraction process.

由于超声能量会在介质中引起现象，从而增强了质量传递，因此功率超声已应用于食品技术中，以增强提取过程。这项工作的目的是对四个不同几何形状的换能器进行声学表征，并评估它们在超声辅助超临界流体中提取牛至中抗氧化剂的性能。换能器在传输到介质中的能量数量不同。设计从基本模型（T1），较大的圆柱头（T2），阶梯形圆形截面超声焊极（T3）和多板配置（T4）不等。根据量热法提供的最高标称功率密度为T4（151.6±7.1 W / L）。T2产生更均匀的声场和更高的声压（150.6±20.5 kPa）。₂在超临界条件下（35 MPa，35°C，2.3％乙醇作为助溶剂）。T4和T2的酚类萃取效率相同（4.0±0.2和4.2±0.2 mg GA / g），就抗氧化能力而言，最佳性能为T4（26.4±1.1μmolTE / g）。在提取的抗氧化剂化合物中，鉴定出了黄酮和黄烷酮。因此，换能器的几何形状会影响传输到介质中的能量的数量和分布，从而确定提取过程的效率。