In this study, ultrasound-assisted extraction (UAE) of Stevia rebaudiana leaf compounds previously treated with ethanol was investigated. Ultrasound power intensity was evaluated and an experimental design was applied to examine the effect of temperature, solvent to leaf ratio and ethanol percentage in the solvent on mass (Y_M) and sweeteners (Y_S) yield, total phenolic content (TPC) and antioxidant activity (AA). The application of the maximum power (165 W) provided the obtaining of greater Y_M and Y_S, and extracts with higher TPC contents and AA. The increase in the solvent/leaf ratio provided the highest Y_M and Y_S, as the increase of ethanol in the solvent, while the temperature promoted an increase only in the Y_M. Maximum values of Y_M (44.7 wt%) and Y_S (88.50 wt%) were obtained using solvent with 40 % ethanol, 50 °C and 15 mL g⁻¹ (solvent/leaf). The extract obtained is constituted by ∼26 wt% of steviol glycosides (GS), corresponding to 9.5, 4.1 and 12.0 wt% of Stevioside, Rebaudioside C and Rebaudioside A, respectively. The analysis of the principal components indicated a high correlation of the variables ethanol percentage in the solvent and solvent to leaf ratio in obtaining extracts with higher TPC content and AA.

在这项研究中，对先前用乙醇处理过的甜叶菊叶化合物的超声辅助提取 (UAE)进行了研究。对超声功率强度进行评估，并应用实验设计来检查温度、溶剂叶比和溶剂中乙醇百分比对质量 (Y _M ) 和甜味剂 (Y _S ) 产量、总酚含量 (TPC) 和抗氧化剂的影响活动（AA）。最大功率（165 W）的应用提供了更大的 Y _M和 Y _S的获得，并且提取物具有更高的 TPC 含量和 AA。溶剂/叶比的增加提供了最高的 Y _M和 Y _S，随着溶剂中乙醇的增加，而温度仅促进了 Y _M的增加。Y _M (44.7 wt%) 和 Y _S (88.50 wt%) 的最大值是使用含有 40% 乙醇的溶剂、50°C 和 15 mL g ^-1（溶剂/叶）获得的。获得的提取物由约 26 wt% 的甜菊糖苷 (GS) 组成，分别对应于 9.5、4.1 和 12.0 wt% 的甜菊苷、莱鲍迪苷 C 和莱鲍迪苷 A。对主要成分的分析表明，在获得具有较高 TPC 含量和 AA 的提取物时，溶剂中的乙醇百分比和溶剂与叶比具有高度相关性。