Fabrication and Characterization of Olive Leaf Polyphenols Loaded Sweet Almond Gum/Gelatin Electrospun Nanofiber

Olive leaf is a rich source of phenolic compounds that have antioxidant and antimicrobial properties. However, easy degradation against environmental stresses, low bioavailability, and the bitter taste of phenolic compounds are the main limitations of its use. This research was done with the aim to encapsulate olive leaf polyphenols in electrospun nanofibers of almond gum/gelatin. For this purpose, after extraction, polyphenols were loaded in different concentrations (0%, 5%, 10%, and 20%) in sweet almond gum/gelatin electrospun nanofibers. Characteristics of electrospun nanofibers of almond gum/gelatin/olive leaf polyphenol were determined by infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). Moreover, the rheological properties of the electrospun solutions were investigated. Results showed that the diameter of electrospun nanofibers increased with an increase in olive leaf polyphenol concentration. AFM results showed that the morphology of the nanofibers was rod-shaped and without disorder. FTIR and XRD data indicated that the polyphenols were effectively loaded within the carriers, and interactions were occurring between gelatin and almond gum. TGA results showed that polyphenol degradation was done in the second step. The rheometric results showed that almond gum/gelatin/polyphenol solutions behaved like Newtonian fluids and the viscosity increased with the increase in polyphenol concentration. The release rate was high in the initial times and gradually decreased with the increase of the process time. This research showed that electrospun nanofibers of sweet almond gum and gelatin loaded with olive leaf polyphenol can be used in food and medicine.