洋葱精油微胶囊制备工艺优化及其品质分析

Optimization of Preparation Technology and Quality of Onion Essential Oil Microcapsules

为得到包埋效果好、品质优良的洋葱精油微胶囊,采用喷雾干燥法,研究壁材种类、芯材-壁材用量比和固形物用量对微胶囊包埋率的影响及在扫描电子显微镜下的形貌、感官性状、包埋度、含水率、溶解度、堆积密度、贮藏稳定性等。结果表明:在复合壁材为阿拉伯胶+β-环糊精(质量比4∶3)、芯材-壁材用量比1∶4(m L/g)、固形物用量20%的条件下,洋葱精油微胶囊包埋率为92.35%;扫描电子显微镜结果显示微胶囊表面连续,呈光滑的球形;且微胶囊具有良好的感官性状,粉末均匀不黏壁,能够有效掩盖洋葱精油的辛辣刺激性气味,易于被消费者接受;在最佳制备条件下微胶囊的包埋度、含水率、溶解度、堆积密度、玻璃化转变温度分别为21.32%、3.69%、97.56%、0.786 g/cm^3、46.35℃,表明微胶囊易于溶解,含水率低,玻璃化转变温度高于一般贮藏温度。因此,最佳制备条件下微胶囊产品品质较优,具有良好的贮藏稳定性及市场接受度。

The purpose of this work was to obtain good quality and high microencapsulation efficiency of onion essential oil microcapsules by spray drying method.Arabic gum,β-cyclodextrin and maltodextrin were evaluated for their use as wall materials.The effect of wall material type,core to wall material（C/M）ratio and solid content on microencapsulation efficiency was investigated.The morphology under scanning electron microscopy（SEM）,sensory attributes,encapsulation degree（ratio between microencapsulated oil and wall material）,water content,solubility,bulk density and storage stability of microcapsules were measured.The results showed that the maximum microencapsulation efficiency of 92.35%was achieved under the following conditions：arabic gum andβ-cyclodextrin mixture（4：3,m/m）as wall material,C/M ratio1：4（m L/g）,and solid content 20%.SEM examination showed that the obtained microcapsules were spherical in shape with smooth and continuous surfaces.The microcapsules had good sensory properties,and were homogenous in size and nonsticky,which could effectively hide the pungent odor of onion essential oil,making the product acceptable to consumers.Moreover,the encapsulation degree,water content,solubility,bulk density and glass transition temperature（T_g）of the microcapsules were 21.32%,3.69%,97.56%,0.786 g/cm^3 and 46.35℃,respectively indicating good solubility,a low water content and a T_g higher than general storage temperature.Therefore,high-quality microcapsules were obtained under the optimized conditions,which had good storage stability and were acceptable to the market.