In the present study, we have optimized by surface response methodology (BBD model) phenolic compounds recovery using microwave-assisted extraction (MAE) as an innovative technique. The extraction was carried out under different experimental conditions: ethanol/water (x₁, 30–80 %), time (x₂, 30–180 s), microwave power (x₃, 500–900 W) and solvent to sample ratio (x₄, 20:1 40:1, v/w). Total phenolics content (TPC) and antioxidant activities (AA) of onion extract were investigated on 2,2−9-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS⁺), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), oxygen radical absorbance capacity (ORAC) tests, and on biological model oxidation, human low-density lipoprotein (LDL). The maximum predicted TPC under the optimal MAE conditions (70 % ethanol), 700 W microwave power, 65 s extraction time and 25 mL g^–1 solvent to solid ratio), was 10.90 ± 0.88 mg GAE g^–1 DW. The AA of MAE or conventional extraction (CE) extract showed similar activities to neutralize DPPH, ABTS or AAPH derived radicals. The modified Gompertz model has been successfully used to describe CDs production kinetic in LDL Cu²⁺-mediated oxidation. This allowed the estimation of the lag time (Tlag) and the oxidation propagation rate (R_p) with precision. LDL oxidation assay showed that red onion extract increased significantly Tlag and giving an increased protection ratio at higher concentration (2.95 μmol L⁻¹) of 180 % and 172 % for MAE and CE methods, respectively. However, R_p and CDs production remained constant. Results showed that microwave used for extraction does not affect the composition and antioxidant properties of onion sample. Red onion may be an important source of bioactive compounds and could promote health consumers.

在本研究中，我们通过表面反应方法（BBD模型）优化了使用微波辅助萃取（MAE）作为创新技术的酚类化合物的回收率。提取物不同的实验条件下进行：乙醇/水（X ₁，30-80％），时间（X ₂，30-180或多个），微波功率（X ₃，500-900 W）和溶剂样品比（X ₄，20：1 40：1，v / W）。研究了2,2-9-叠氮基-双-3-乙基苯并噻唑啉-6-磺酸（ABTS ⁺），1,1-二苯基-2-吡啶并肼基上洋葱提取物的总酚含量（TPC）和抗氧化活性（AA）。自由基（DPPH），氧自由基吸收能力（ORAC）测试以及对生物模型氧化的人类低密度脂蛋白（LDL）的检测。在最佳MAE条件（70％乙醇），700 W微波功率，65 s提取时间和25 mL g ^–1溶剂与固体比的条件下，最大预测TPC为10.90±0.88 mg GAE g ^–1 DW。MAE的AA或常规提取（CE）提取物显示出相似的中和DPPH，ABTS或AAPH衍生基团的活性。改进的Gompertz模型已成功用于描述LDL Cu ²⁺介导的氧化过程中CD的产生动力学。这样就可以估计滞后时间（Tlag）和氧化传播速率（R _p）。LDL氧化分析表明，对于MAE和CE方法，红洋葱提取物显着增加Tlag并在较高浓度（2.95μmolL ^-1）时分别提供180％和172％的保护率。但是，R _p和CD的产量保持不变。结果表明，微波提取对洋葱样品的组成和抗氧化性能没有影响。红洋葱可能是生物活性化合物的重要来源，并且可以促进健康消费者。