无溶剂微波萃取肉桂精油及成分分析

Solvent-free Microwave Extraction and Composition of Cinnamon Essential Oil

摘要:

优化无溶剂微波萃取肉桂油的工艺条件，结合气相色谱质谱联用仪进行肉桂油成分鉴定，同时探究该工艺提取肉桂精油的体外抗氧化能力和肉桂表面微观形貌，并与水蒸气蒸馏法萃取肉桂油进行对比。以肉桂精油得率为评价指标，通过正交试验得出最佳试验条件，提取时间60 min、微波功率450 W、含水率60%、浸润时间2.5 h；在该试验条件下的肉桂精油得率为3.15%，较传统的水蒸气蒸馏法提高了35.78%；采用气相色谱质谱联用仪对肉桂精油进行成分分析，并通过质谱库与保留指数验证，从无溶剂微波工艺萃取的肉桂精油中共鉴定出了24种化合物，主要包括肉桂醛（67.69%）、丁香酚（11.36%）、芳樟醇（4.26%）、柠檬烯（2.40%）等，且肉桂醛及柠檬烯的含量较水蒸气蒸馏萃取肉桂油分别提高了14.49%和34.51%，表明无溶剂微波萃取肉桂油有更高的药理活性；扫描电子显微镜SEM观察到无溶剂微波萃取后的肉桂样品有明显的空隙和大量不规则的空腔结构；无溶剂微波萃取肉桂油对DPPH自由基和羟基自由基的清除作用的IC50分别为，2.10 mg/mL和0.17 mg/mL，优于传统水蒸气蒸馏法萃取肉桂油；综上，无溶剂微波萃取工艺是种较理想的提取肉桂精油的方法，具有提取效率高、肉桂精油得率高及品质优良等优点。

Abstract:

A solvent-free microwave extraction (SFME) process was optimized to extract cinnamon essential oil, and the components of the extract were analyzed by gas chromatography/mass spectrometry. The in vitro antioxidant capacity and surface micromorphology of the cinnamon essential oil extracted by SFME were also examined and compared with those of cinnamon essential oil extracted by steam distillation (SD). Using the oil yield as an indicator, the optimal extraction conditions were obtained by conducting orthogonal tests. The conditions are as follows: extraction time, 60 min; microwave power, 450 W; moisture content, 60%; and infiltration time, 2.5 h. The essential oil yield under these conditions was 3.15%, which is 35.78% higher than that of the traditional SD. Gas chromatography/mass spectrometry was used to analyze the composition of the extracted cinnamon essential oil, and the results were verified using mass spectrum library and retention indexes. In total, 24 compounds were identified. The main components include cinnamaldehyde (67.69%), eugenol (11.36%), linalool (4.26%), and limonene (2.40%). The cinnamaldehyde and limonene content in the cinnamon oil extracted by SFME was 14.49% and 34.51% higher, respectively, than that extracted by SD, indicating that the cinnamon oil extracted by SFME has superior pharmacological activity. The SEM results suggest that the solvent-free microwave extracted cinnamon essential oil has distinct voids and many irregular cavities. The IC50 values for DPPH (2.10 mg/mL) and hydroxyl free radicals (0.17 mg/mL) in the cinnamon oil extracted by SFME are higher than those for the cinnamon oil extracted by SD. In summary, SFME is a suitable method for extracting cinnamon essential oil because high extraction efficiency, high oil yield, and excellent oil quality can be achieved using this method.