丁香油的超临界CO_2萃取及其微胶囊的制备

The Supercritical CO_2 Extraction and Microencapsulation of Clove Oil

在70℃和10MPa条件下通过对丁香花蕾进行超临界CO2萃取得到丁香油，萃取率达19%-21％。气质联用分析结果表明，丁香油中主要化学成分包括丁香酚、β-石竹烯和乙酰基丁香酚等。以丁香油为囊芯，探讨利用干酵母细胞作为囊壁材料制备微胶囊的可行性。通过正交试验考察了包埋温度、包埋时间、丁香油与干酵母配比（芯材比）对微胶囊化丁香油的影响。结果表明，在包埋温度70℃、包埋时间9h和芯材比为1：1（w／w）的条件下，微胶囊中丁香油包埋率达到41．26％。通过扫描电镜观察，丁香油微胶囊呈规则的球形，大小均一，颗粒直径在2．0-4．0μm。在100℃下对经微胶囊化的丁香油加热20h，其挥发率只有15．04％，远低于相同条件下丁香油的挥发率（58．29%）。这种新型的微胶囊化方法，具有制备过程简单、包埋率高和不引入有机溶剂的优点。

The clove oil （CvO） was extracted from dried clove bud via supercritical CO2 extraction （SC-CO2）, and the production of the CvO microcapsules by using the dried yeast （S. cerevisiae） cells as wall materials was examined. The experiments show that the yield of CvO by SC-CO2 extraction at 70℃ and 10 MPa is 19%-21%, and the GC-MS analysis indicates that the CvO extracted are mainly composed of eugenol, β-caryophyllene and eugenol acetate. Orthogonal arrays design was used to investigate the effects of encapsulating temperature, encapsulating time and the ratio of CvO to dried yeast on the microencapsulation of CvO. The results show that the encapsulating rate of CvO may reach 41.26% under the conditions of encapsulating temperature of 70℃, encapsulating time of 9 h and the ratio of CvO to dried yeast of 1： 1（w/w）. The morphologies of the prepared CvO microcapsules observed by scanning electron microscope （SEM） are spherical particles with diameters of 2.0-4.0μm. After being encapsulated in yeast cell, the volatile velocity of CvO is 15.04% under the condition of 100℃ and heating for 20 h, which is much lower than that of 58.29% of un-encapsulated CvO under the same conditions. It is concluded that the proposed novel method of microencapsulation with dried yeast cell as wall materials is simple, efficient and free of using organic solvent.