不同壁材对绿咖啡油微胶囊微观结构及其热稳定性的影响

Effects of Different Wall Materials on the Microstructure and Ther-mal Stability of Green Coffee Oil Microcapsules

分别以阿拉伯胶(gum arabic,GA)与大豆分离蛋白(soybean protein isolate,SPI)、乳清分离蛋白(whey protein isolate,WPI)和酪蛋白酸钠(sodium caseinate,SC)作为壁材,通过复合凝聚法制备3种绿咖啡油(green coffee oil,GCO)微胶囊。结合不同表征技术手段,对壁材的浊度、红外光谱特征、表观形貌以及荧光共定位进行分析;比较3种绿咖啡油微胶囊的包封效率、形貌、粒径、结构表征及热稳定性。结果表明,阿拉伯胶与不同蛋白之间通过静电相互作用形成复聚物,可作为包埋绿咖啡油的新型壁材;红外光谱分析表明,3种壁材均能较好地包埋绿咖啡油,包埋率从大到小依次为SPIGA-GCO(69.26%)>SCGA-GCO(58.69%)>WPIGA-GCO(52.57%);绿咖啡油微胶囊的微观结构表面平坦,无明显裂纹,其中SPIGA-GCO中油滴分布较为均匀;差示扫描热量法分析表明,微胶囊热变性温度较高(103.93~108.33℃),具有良好的热稳定性。研究结果表明,SPIGA-GCO微胶囊性能明显优于其他2种壁材制备的微胶囊产品。本研究为开发稳定有效的绿咖啡油微胶囊产品提供技术支撑,也为绿咖啡油的高值化利用提供理论依据。

In this paper,three types of green coffee oil microcapsules were prepared by complex coacervation using the combination of gum arabic(GA)with soybean isolate protein(SPI),whey isolate protein(WPI)and sodium caseinate(SC)as wall materials,respectively.The turbidity,infrared spectral characteristics,apparent morphology and fluores-cence co-localization of the wall materials were analyzed by combining different characterization techniques;the en-capsulation efficiency,morphology,particle size,structural characterization and thermal stability of the three green coffee oil microcapsules were compared.Gum arabic and different proteins formed complexes through electrostatic interactions,which can be used as a new wall material for encapsulating green coffee oil.Infrared spectral analysis showed that the three wall materials could encapsulate green coffee oil better.The encapsulation rate in a descending order was SPIGA-GCO(69.26%),SCGA-GCO(58.69%),WPIGA-GCO(52.57%).The microstructure of green coffee oil microcapsules had a flat surface without obvious cracks,among which the oil droplets were more uniformly distrib-uted in SPIGA-GCO.DSC analysis showed that the thermal denaturation temperature of microcapsules was higher(103.93-108.33℃),with good thermal stability.The results showed that the performance of SPIGA-GCO microcap-sules was significantly better than the microcapsule products prepared from the other two wall materials.This study would provide technical support for the development of stable and effective green coffee oil microencapsulated products,and also provide a theoretical basis for the high value utilization of green coffee oil.