Production and characterization of nanocapsules encapsulated linalool by ionic gelation method using chitosan as wall material

Abstract Linalool has been extensively applied in various fields, such as flavoring agent, perfumes, cosmetics and medical science. However, linalool is unstable, volatile and readily oxidizable. A sensitive substance can be encapsulated in a capsule, so encapsulation technology can solve these problems. In this paper, linalool-loaded nanocapsules (Lin-nanocapsules) were prepared via the ionic gelation method and Lin-nanocapsules were characterized. The results of Fourier transformation infrared spectroscopy (FTIR) showed that linalool was successfully encapsulated in the wall materials. Scanning electron microscopy (SEM) results demonstrated that the shapes of Lin-nanocapsules, with smooth surfaces, were nearly spherical. Lin-nanocapsule average particle size was 352 nm and its polydispersity index (PDI) was proved to be 0.214 by the results of dynamic light scattering (DLC). Thermogravimetric results indicated that linalool loading capacity (LC) was 15.17%, and encapsulation could decrease linalool release and increase linalool retaining time under the high temperature. Oscillatory shear and steady-state shear measurements of Lin-nanocapsule emulsions were systematically investigated. The results of steady-state shear showed that Lin-nanocapsule emulsion, which was Newtonian only for high shear rate, was non-Newtonian. It was proved by oscillatory shear that when oscillation frequency changed from low to high, Lin-nanocapsules emulsion changed from viscous into elastic.