Production and Characterization of Gelatin Spherical Particles Formed via Electrospraying and Encapsulated with Polyphenolic Antioxidants from Momordica charantia

This study dealt with the production and characterization of gelatin nanospheres and encapsulation with Momordica charantia, commonly known as bitter gourd fruit vegetable extract (BGE). The impact of encapsulation and increasing the encapsulate loading on various physiochemical characteristics of gelatin polymeric entities as well as antioxidative attributes of BGE was studied. Nanospheres were formed via an electrospraying process conducted at 20 kV, 0.5 mL/h, and 10 cm of voltage, flow rate, and emitter/collector distance, respectively. The spherical beads were encapsulated with BGE at 5 to 15% (w/w%) loading rate. Morphological analysis through scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated that nanospheres could be successfully produced. Furthermore, nanosphere encapsulation of the extract was demonstrated in transmission electron microscope (TEM) micrographs. Spectroscopic analysis indicated no chemical interactions between core and wall materials. The thermal stability of encapsulated nanoparticles slightly increased and the glass transition temperature (T_g) disappeared due to increased crystallinity. Thermogravimetric graphs of encapsulated spherical beads, at all core loadings, showed an additional phase ranging from 138 to 249 °C, overlapping with the BGE’s main TGA degradation phase. The presence of this phase, which was absent from empty bead thermograms, confirmed encapsulation occurrence during electrospraying process. Furthermore, an average of 80% of antioxidative content and potency of the extract was conserved during the encapsulation process. Moreover, phenolic content and antioxidative activity of the encapsulated extract showed higher stability than extracts while stored at refrigerated and ambient conditions.