Food Process Engineering Group, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
Langmuir. 2010 Dec 21;26(24):19106-13. doi: 10.1021/la1033542. Epub 2010 Nov 24.
Despite the fair number of microencapsulation principles that have been developed, the actual protection and targeted delivery of sensitive ingredients remains a challenge in the food industry. A suitable technique should use food-grade and inexpensive materials, and ensure tight control over the capsule size and release trigger mechanism. For example, encapsulates may need to survive the low pH of the stomach to release their contents in the neutral environment of the small intestine. In this work we present layer-by-layer (LbL) microcapsules assembled from whey protein isolate (WPI), high-methoxyl pectin (HMP) and WPI-fibrils. The narrow size distribution of these capsules is determined by the oil-in-water droplets used as templates, and their mechanical properties and pH response can be tuned by the number of layers adsorbed. Capsules with more than eight layers have a mechanical strength comparable to chemically cross-linked polymer capsules, because of the reinforcement by the WPI-fibrils in combination with the shell completion. Typically, capsules with five layers survive pH 2 for more than 2 h, but dissolve within 30 min at pH 7. At higher number of layers, the capsules are even more stable. Contrary to other encapsulates, these capsules can be dried and are suitable for application in dry products.
尽管已经开发出了相当数量的微胶囊化原理，但在食品工业中，如何有效地保护和靶向输送敏感成分仍然是一个挑战。一种合适的技术应该使用食品级和廉价的材料，并确保对胶囊尺寸和释放触发机制进行严格控制。例如，封装物需要在胃酸的低 pH 值环境中存活下来，以便在小肠的中性环境中释放其内容物。在这项工作中，我们提出了由乳清蛋白分离物（WPI）、高甲氧基果胶（HMP）和 WPI 原纤维组装而成的层层（LbL）微胶囊。这些胶囊的窄粒径分布是由用作模板的油包水液滴决定的，通过吸附的层数可以调节它们的机械性能和 pH 响应。具有超过 8 层的胶囊具有与化学交联聚合物胶囊相当的机械强度，因为 WPI 原纤维与壳层完成相结合提供了增强作用。通常，具有 5 层的胶囊在 pH 2 下可以存活超过 2 小时，但在 pH 7 下 30 分钟内就会溶解。在更多的层数下，胶囊更加稳定。与其他封装物不同，这些胶囊可以干燥，适用于干燥产品的应用。
