In this study, oil extraction from Niger seeds was evaluated with different microwave irradiation times (0–200 s) and pulsed electric fields (PEF) intensities (0–5 kV/cm) as pretreatments. Then, oil extraction was completed with a screw press at different rotation speeds (11–57 rpm). Quality parameters including extraction efficiency, acidity and peroxide values (PVs), chlorophyll, and phenolic contents along with fatty acid profiles and tocopherol levels of the extracted oils were determined as responses. With enhancements in microwave time, PEF intensity and press rotation, the chlorophyll contents, acidity/PVs, and total phenolics of oils increased similar to oil extraction efficiency although it was reduced later. The optimized conditions selected by response surface methodology were determined as 156.23 s, 1.18 kV/cm, and 20 rpm for microwave time, PEF intensity and press speed, respectively. Fatty acid analysis revealed that linoleic acid was the most predominant fatty acid in the extracted oil. Application of the mentioned pretreatments may lead to a reduction in unsaturated fatty acids and escalation of saturated ones (p < .05). High‐performance liquid chromatography results indicated that α‐tocopherols are the most common tocopherols in Niger seed oil and microwave‐PEF pretreatments may lead to 2.79% increase in tocopherols content.

中文翻译：

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微波脉冲电场预处理优化了尼日尔籽油的提取和质量评估。

在这项研究中，尼日尔种子的采油在不同的微波照射时间（0–200 s）和脉冲电场（PEF）强度（0–5 kV / cm）下进行了预处理。然后，用螺旋压力机以不同的转速（11-57 rpm）完成油的提取。确定质量参数，包括提取效率，酸度和过氧化物值（PVs），叶绿素和酚含量以及提取油的脂肪酸谱和生育酚水平，作为响应。随着微波时间，PEF强度和压榨旋转时间的增加，油中的叶绿素含量，酸度/ PVs和总酚含量增加，类似于采油效率，尽管后来有所降低。通过响应面法选择的优化条件确定为156.23 s，1.18 kV / cm，微波时间，PEF强度和压制速度分别为20和rpm。脂肪酸分析表明，亚油酸是提取油中最主要的脂肪酸。进行上述预处理可能会导致不饱和脂肪酸减少，饱和脂肪酸升高（p  <.05）。高效液相色谱结果表明，α-生育酚是尼日尔种子油中最常见的生育酚，微波-PEF预处理可能会使生育酚含量增加2.79％。