Synthesis and properties research on the nanocapsulated capsaicin by simple coacervation method

A new nanoencapsulation was established in which small nanocapsules with a natural polymeric wall could be fabricated, capsulizing the capsaicin having pungent odor. The new nanoencapsulation is based on a simple coacervation process. In this technique, gelatin was used as the wall material of the nanocapsules, and an insoluble polymer film was formed after cross-linking reaction. The shell formation mechanism and the effects of the process conditions such as shearing force, the gelatin viscosity, cross-linking time, and so on, on the particle size of the nanocapsulated capsaicin (NC) agents were discussed. Meanwhile, the morphology and size distribution of the nanocapsules prepared by the most suitable conditions, were analyzed by Fourier transform infrared (FTIR) spectroscopy, laser particle size analyzer, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The NC agents had a mean particle size of about 100nm. Moreover, the thermal properties of the NC agents were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was demonstrated that the melting point and thermal pyrolysis temperature of the NC agents were improved from 75 to 100 degrees C, 230 to 240 degrees C, 310 to 320 degrees C, and from 450 to 540 degrees C compared with that of the uncovered capsaicin, which were caused by the encapsulation of the cross-linked gelatin over the surface of the capsaicin.