乳液粒径对橙皮精油微胶囊物理性质和氧化稳定性的影响

本文以橙皮精油为芯材,变性淀粉和麦芽糊精为壁材,通过高压(1000、2500、3500和22000 psi)均质制备了不同粒径橙油乳液,从而探讨乳液粒径对喷雾干燥橙油微胶囊平均粒径、包埋率、总油量、含水量、微观形貌以及重组乳液粒径分布的影响。同时以柠檬烯氧化程度评价微胶囊稳定性并预测其货架期。结果表明,均质压力越高,乳液粒径越小。乳液粒径对微胶囊的总油量(1.5 g/20 g)、包埋率(>95%)和含水量(<4%)没有明显影响,但会影响微胶囊的平均粒径、微观形貌以及重组乳液的粒径分布。乳液粒径越小,微胶囊平均粒径越小,表面越光滑,重组乳液也具有更窄的粒径分布。微胶囊在37 ℃贮藏5周,经零级动力学方程拟合氧化柠檬烯/柠檬烯(mg/g)变化的结果表明,以22000 psi制备的微胶囊货架期可长达11周左右,是其余微胶囊货架期的2.97~4.63倍。研究结果可为喷雾干燥精油微胶囊的工艺优化及质量控制提供理论参考。

Effect of Emulsion Size on the Physic Properties and Oxidation Stability of Orange Oil Microcapsule

To explore the emulsion size effects on the physic properties and oxidation stability of spray-dried orange oil microcapsule, different particle size emulsion were prepared by high pressure homogenization (1000, 2500, 3500 and 22000 psi) with modified starch and maltodextrin as wall materials and then spray-dried to produce orange oil microcapsule. The physical properties of microcapsules were evaluated including the average particle size, oil encapsulation efficiency, water content, microstructure and reconstituted emulsion size. Limonene oxidation speed was analyzed to evaluate the storage stability of microcapsule and predicted shelf-life. The results showed that emulsion particle size decreased with the increasing of homogenization pressure. The emulsion size had no significant effect on the total oil content (1.5 g/20 g), oil encapsulation efficiency (>95%) and water content (<4%) of the microcapsule, but it would affect the average particle size, micromorphology of the microcapsules and particle size distribution of reconstituted emulsion. The microcapsule had a smaller average particle size and smoother surface when the emulsion particle size decreased. The reconstituted emulsion had a narrower particle size distribution. Microcapsules were stored at 37℃ for 5 weeks to detect change of limonene 1, 2-epoxide/limonene (mg/g). According to zero-order model, the shelf life of the microcapsules prepared at 22000 psi was predicted as 11 weeks, which was 2.97~4.63 times that of the other microcapsules. The results can provide a theoretical reference for the optimization and quality control of spray drying essential oil microcapsules.