Subcritical water extraction (SWE) is a highly effective technique for extracting monoterpenes at elevated pressures and temperatures using only water solvent. This study investigated SWE of monoterpenes, including γ-terpinene, -cymene, thymol, carvacrol, and thymoquinone, under varying extraction conditions of temperature (110–200 ℃) and time (5–20 min). The extract was qualitatively and quantitatively analyzed by gas chromatography. The maximal extraction conditions of -cymene (0.11 ± 0.03 mg/g), thymol (0.40 ± 0.02 mg/g), carvacrol (5.28 ± 0.19 mg/g), and thymoquinone (1.28 ± 0.11 mg/g) were obtained at temperature/time of 150 °C/5 min, 200 °C/5 min, 200 °C/5 min, and 110 °C/5 min, respectively. Non-oxygenated monoterpenes, such as γ-terpinene and -cymene, were either undetected or extracted in small quantities using SWE and were found to be more suited for organic solvent extraction. Oxygenated monoterpenes, such as thymol, carvacrol, and thymoquinone, exhibited optimal extraction when using SWE. By identifying the optimal conditions, SWE can be an efficient technique for selectively extracting target compounds from thyme. The selectivity of SWE could have practical applications in extracting desired compounds from a variety of industrials. SWE technology can be easily implemented on an industrial scale.

中文翻译：

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使用亚临界水从百里香（Thymus vulgaris L.）中高效提取含氧单萜的强化工艺


亚临界水萃取 (SWE) 是一种仅使用水溶剂在高压和高温下萃取单萜的高效技术。本研究研究了在不同的温度（110–200 ℃）和时间（5–20 分钟）提取条件下单萜的 SWE，包括 γ-萜品烯、-伞花烯、百里香酚、香芹酚和百里醌。采用气相色谱法对提取物进行定性和定量分析。伞花烃 (0.11 ± 0.03 mg/g)、百里香酚 (0.40 ± 0.02 mg/g)、香芹酚 (5.28 ± 0.19 mg/g) 和百里醌 (1.28 ± 0.11 mg/g) 的最大提取条件是在一定温度下获得的。 /时间分别为150°C/5分钟、200°C/5分钟、200°C/5分钟和110°C/5分钟。非氧化单萜，例如 γ-萜品烯和 伞花烃，要么未被检测到，要么使用 SWE 提取少量，并且被发现更适合有机溶剂提取。使用 SWE 时，含氧单萜（例如百里酚、香芹酚和百里醌）表现出最佳提取效果。通过确定最佳条件，SWE 可以成为从百里香中选择性提取目标化合物的有效技术。 SWE 的选择性可以在从各种工业中提取所需化合物方面具有实际应用。 SWE技术可以很容易地在工业规模上实施。