超声波法制备八角茴香油-β-环糊精微胶囊及其表征分析

为提高八角茴香油的稳定性,采用超声波法制备八角茴香油-β-环糊精微胶囊。以包埋率为评价指标,通过正交试验优化制备工艺,并考察微胶囊的加热释放特性。结果表明,最佳制备工艺为八角茴香油与β-环糊精质量比1∶6(g/g)、超声时间40 min、超声温度50℃、超声功率198 W,在此条件下包埋率为94.21%,载药量为6.93%,平均粒径为2.53μm。超声温度和超声功率的变化对微胶囊包埋率的影响显著。红外光谱、差示扫描量热分析和热重分析证实了微胶囊的形成。释放特性表明,200℃条件下加热120 min,八角茴香油保留率仅剩4.60%,而相同温度和时间条件下,微胶囊中八角茴香油保留率为78.38%,是八角茴香油的17.04倍,八角茴香油被包埋后热稳定性提高。超声波法和饱和水溶液法制备微胶囊相比,载药量相差不大,但超声制备的微胶囊包埋率及收率比饱和水溶液法分别提高7.80%和4.98%;超声制备微胶囊包埋率、收率及载药量比研磨法分别提高14.68%、1.88%和1.85%。超声波法是制备高质量八角茴香油-β-环糊精微胶囊的简便可行方法,八角茴香油被包埋后稳定性提高,有望应用于食品保鲜领域。

Ultrasonic Preparation and Characterization of Star Anise Oil-β-Cyclodextrin Microcapsule

Microcapsules of star anise oil with β-cyclodextrin were prepared by an ultrasonic method in attempt to improve the stability of star anise oil. An orthogonal array design was used to optimize the preparation conditions for increased embedding rate. Thermal release characteristics of the microcapsules were also investigated. The optimized conditions were obtained as follows: mass ratio of star anise oil to β-cyclodextrin, 1:6 (g/g); ultrasonication time, 40 min; temperature, 50 ℃ and ultrasonic power, 198 W. Under these conditions, the embedding rate, drug loading and average diameter of microcapsules were 94.21%, 6.93%, and 2.53 μm, respectively. Temperature and ultrasonic power had significant effects on the embedding rate. The successful formation of microcapsules of star anise oil in β-cyclodextrin was confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Results of thermal release characteristics demonstrated that only 4.60% of free star anise oil was retained after being heated at 200 ℃ for 120 min, while at the same time and temperature the retention rate of star anise oil in microcapsules was 78.38%, which was 17.04 times higher than that of free star anise oil, indicating improvement of the thermal stability of star anise oil by encapsulation. There was no significant difference in drug loading of the microcapsules prepared by the ultrasonic and saturated aqueous solution methods, while microcapsules prepared by the ultrasonic method had higher embedding rate and recovery with 7.80% and 4.98% improvement as compared to those prepared by the saturated aqueous solution method, respectively. Meanwhile, the microcapsules prepared by the ultrasonic method exhibited higher embedding rate (by 14.68%) and recovery (by 1.88%), and had higher drug loading (by 1.85%) than the kneading method. The ultrasonic method is an easy and feasible method for preparing star anise oil-β-cyclodextrin microcapsules with high quality. Encapsulation with β-cyclodextrin can provide an efficient way to increase the stability of star anise oil, thereby making it valuable for food preservation applications.