响应面试验优化香根草油的超临界CO_2萃取工艺及其萃取物分析

Supercritical CO_2 Extraction and Chemical Composition Analysis of Vetiver Essential Oil

以新鲜香根草根须为原料,通过单因素试验研究粒径、装料系数、萃取压力、萃取温度、CO2流率及萃取时间对超临界CO2萃提香根草油得率的影响。在此基础上,选取萃取压力、萃取温度和CO2流率为影响因素,以香根草油得率为响应值,采用Box-Behnken方法设计试验,进行响应面分析。结果表明：超临界CO2萃取香根草油的适宜工艺参数为粒径范围60～80目、装料系数0.8、萃取压力22.61 MPa、萃取温度35.41℃、CO2流率1.65 L/min、萃取时间1.5 h。在此条件下预测香根草油得率达到7.780%,实验验证值为7.762%,与预测一致。采用气相色谱-质谱法对超临界萃取的香根草油进行了成分分析,鉴定出18种化合物,占总萃取物的69.88%。其中主要成分为柏木烯醇、脱氢香橙烯、月桂烯酮以及香根草特有的香根醇、香根酮等化合物,并按照应用领域对其进行了分类总结。

This work was conceived to optimize the extraction of essential oil from fresh vetiver roots by supercritical carbon dioxide fluid extraction（SCFE-CO2）. Firstly, one-factor-at-a-time（OFAT） method was employed to examine the effects of particle size of powdered vetiver roots, volume charge coefficient, extraction pressure, extraction temperature, CO2 flow rate and extraction time on the yield of vetiver oil. Subsequently, three key factors including extraction temperature, extraction pressure and CO2 flow rate were optimized by response surface methodology（RSM） based on Box-Behnken design using oil yield as the response variable. The results indicated that the optimum conditions that provided the highest extraction yield were determined as follows： raw material granularity, 60–80 mesh; volume charge coefficient, 0.8; extraction pressure, 22.61 MPa; extraction temperature, 35.41 ℃; CO2 flow rate, 1.65 L/min; and extraction time, 1.5 h. Under these conditions, the predicted maximum yield of vetiver oil was 7.780%, agreeing with the experimental value（7.762%）. The chemical composition of the extracted essential oil was analyzed by GC-MS. A total of 18 compounds which accounted for 69.88% of the total extract were identified including 8-cedren-13-ol, dehydro-aromadendrene, myrcenone, vetiverol and vetiverone as the main components. The applications of these components in various fields were summarized in this work.