Physics and Physical Chemistry of Foods, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands.
J Agric Food Chem. 2012 Sep 19;60(37):9502-11. doi: 10.1021/jf3024529. Epub 2012 Sep 5.
In this study, we produced microcapsules using layer-by-layer adsorption of food-grade polyelectrolytes on an emulsion droplet template. We compared the mechanical stability of microcapsules to shells consisting of alternating layers of ovalbumin-high methoxyl pectin (Ova-HMP) complexes and semi-flexible ovalbumin (Ova) fibrils (average contour length, L(c) ~ 200 nm), with microcapsules built of alternating layers of lysozyme-high methoxyl pectin (LYS-HMP) complexes and lysozyme (LYS) fibrils. Two types of LYS fibrils were used: short and rod-like (L(c) ~ 500 nm) and long and semi-flexible (L(c) = 1.2-1.5 μm). At a low number of layers (≤4), microcapsules from Ova complexes and fibrils were stronger than microcapsules prepared from LYS complexes and fibrils. With an increase of the number of layers, the mechanical stability of microcapsules from LYS-HMP/LYS fibrils increased significantly and capsules were stronger than those prepared from Ova-HMP/Ova fibrils with the same number of layers. The contour length of the LYS fibrils did not have a significant effect on mechanical stability of the LYS-HMP/LYS fibril capsules. The stiffer LYS fibrils produce capsules with a hard but more brittle shell, whereas the semi-flexible Ova fibrils produce capsules with a softer but more stretchable shell. These results show that mechanical properties of this type of capsule can be tuned by varying the flexibility of the protein fibrils.
在这项研究中，我们使用食品级聚电解质在乳液液滴模板上逐层吸附来生产微胶囊。我们比较了微胶囊与由交替层的卵清蛋白-高甲氧基果胶（Ova-HMP）复合物和半柔性卵清蛋白（Ova）原纤维组成的壳的机械稳定性，微胶囊由交替层溶菌酶-高甲氧基果胶（LYS-HMP）复合物和溶菌酶（LYS）原纤维组成。使用了两种类型的 LYS 原纤维：短棒状的（L(c)~500nm）和长而半柔性的（L(c)=1.2-1.5μm）。在层数较低（≤4）时，由 Ova 复合物和原纤维制成的微胶囊比由 LYS 复合物和原纤维制成的微胶囊更强。随着层数的增加，由 LYS-HMP/LYS 原纤维制成的微胶囊的机械稳定性显著增加，并且与具有相同层数的 Ova-HMP/Ova 原纤维制备的胶囊相比，其强度更高。LYS 原纤维的长度对 LYS-HMP/LYS 原纤维胶囊的机械稳定性没有显著影响。刚性较强的 LYS 原纤维产生的壳更硬但更易碎，而半柔性的 Ova 原纤维产生的壳更柔软但更具弹性。这些结果表明，通过改变蛋白质原纤维的柔韧性可以调节这种类型胶囊的机械性能。
