亚临界水提取洋葱精油的研究

为获得提取洋葱精油的新提取技术，设计了适合工业化应用的2L亚临界水提取装置；选用具有岭南特色的红葱头为原料进行了亚临界水提取洋葱精油的研究。考察了提取方式、提取时间、温度、压力对洋葱精油的提取得率及含硫化合物浓度的影响，并对液液萃取中溶剂的种类和萃取次数进行了研究，得到了洋葱精油的亚临界水提取最佳工艺：静态提取、提取时间30 min，压力5 MPa，100～150 ℃的连续程序升温，石油醚为萃取溶剂，萃取2次。此条件下洋葱精油的提取得率为0.362％，含硫化合物浓度为97.36 g/kg。与传统提取法相比，亚临界水提取法具有提取时间短、效率高、能耗低、产品质量高等优点。2L亚临界水提取装置自动化程度高，操作简便。

Extraction of Onion Essential Oil by Subcritical Water

In order to get a new technology of extraction of onion essential oil, 2L apparatus of subcritical water extraction (SWE) suitable for industrial production was designed. SWE of onion essential oil from red onion of Lingnan characteristics was studied. Effects of different extraction modes, extraction time, pressure and temperature on the extraction yield of onion essential oil and sulphur concentration were investigated，and the different extraction solvents and extraction times were researched in liquid-liquid extraction procedure. The optimal conditions of extraction of onion essential oil with subcritical water were static extraction, 100~150℃sequential program temperature increasing extraction for 30min, 5MPa, petroleum ether as extraction solvent for two times. Under the conditions, the extraction yield of onion essential oil was 0.362 %, and the sulphur concentration was 97.36 g/kg. Compared to the conventional steam distillation (SD) and ultrasonic assisted extraction method (USE), the subcritical water extraction shows shorter extraction time, high efficiency, low energy consumption and good product quality, etc. 2L apparatus of SWE has high automation level and simple operation.