Homogenization-circulating ultrasound in combination with an aqueous enzymatic pretreatment microwave-assisted extraction (HCUEPM) technique was successfully applied to extract kernel oil and essential oil from Litsea cubeba fruits. After screening the types and concentrations of enzymes, a 3 % pectinase aqueous solution was chosen. The Plackett–Burman design was used to screen eight parameters that might affect the yield of kernel oil and essential oil to identify significant variables. The best conditions were then predicted by further optimizing statistically significant factors via the Box–Behnken design. The optimal conditions were as follows: stirring speed of 1000 r/min, environmental pH of 5, homogenization time of 4 min, duty cycle of 20 %, ultrasound irradiation power of 400 W, incubation temperature of 52.78 °C, liquid–solid ratio of 9.31 mL/g, and incubation time of 2.53 h. Three parallel experiments were conducted under these conditions, yielding actual kernel oil at 240.56 ± 11.07 mL/kg DW and essential oil at 64.89 ± 3.1 mL/kg DW, which are close to the theoretical values. Compared with the HCUEPM method, the homogenization-microwave-assisted hydrodistillation (HMHD) method yielded 65.63 ± 3.2 mL/kg DW of essential oil but could not extract kernel oil. These findings demonstrate that the HCUEPM used in this study can efficiently extract a significant amount of kernel oil and essential oil from L. cubeba fruits in a short period of time. GC–MS analysis of the kernel oil and essential oil extracted via different methods revealed no significant differences in composition. The main components of the essential oil were D-limonene, trans-citral, cis-citral, and citronellal. The main components of the kernel oil were C10 and C12 medium-chain fatty acids, laying the foundation for the potential application of L. cubeba kernel oil and essential oil in the field of human health.

中文翻译：

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均质循环超声结合水性酶前处理微波辅助提取山苍子果实仁油和精油


均质循环超声结合水性酶前处理微波辅助提取 （HCUEPM） 技术成功应用于山苍子果实的仁油和精油提取。筛选酶的种类和浓度后，选择 3% 果胶酶水溶液。采用 Plackett-Burman 设计筛选可能影响仁油和精油产量的 8 个参数，以确定显著变量。然后，通过 Box-Behnken 设计进一步优化具有统计显著性的因子，预测最佳条件。最佳条件为：搅拌速度 1000 r/min，环境 pH 值 5，均质时间 4 min，占空比 20 %，超声照射功率 400 W，孵育温度 52.78 °C，液固比 9.31 mL/g，孵育时间 2.53 h。在此条件下进行 3 次平行试验，得到实际果仁油 240.56 ± 11.07 mL/kg DW，精油 64.89 ± 3.1 mL/kg DW，均接近理论值。与 HCUEPM 法相比，均质-微波辅助加氢蒸馏 （HMHD） 法可提取 65.63 ± 3.2 mL/kg DW 的精油，但无法提取仁油。这些发现表明，本研究中使用的 HCUEPM 可以在短时间内有效地从 L. cubeba 果实中提取大量的仁油和精油。对仁油和通过不同方法提取的精油进行 GC-MS 分析，结果显示其成分无显著差异。精油的主要成分是 D-柠檬烯、反柠檬醛、顺柠檬醛和香茅醛。 仁油的主要成分为 C10 和 C12 中链脂肪酸，为立方叶腊仁油和精油在人类健康领域的潜在应用奠定了基础。