Production of core-shell nanofibers from zein and tragacanth for encapsulation of saffron extract.

In this study, encapsulation of aqueous saffron extract (ASE) was studied using a core-shell nanofiber structure (zein-tragacanth) via coaxial electrospinning technique. Morphological features of nanofibers were investigated under different processing conditions (polymer concentration and applied voltage). The nanofibers produced under optimum criteria had diameter in a range of 95 to 271 nm. Concentration of zein and percentage of ASE were found to be critical factors affecting loading capacity (LC) and encapsulation efficiency (EE). The range of LC and EE were 3.57-9.52% and 60.89-91.55%, respectively. FTIR and differential scanning calorimetry (DSC) characterizations demonstrated that ASE was appropriately encapsulated in the nanofibers matrix with high thermal stability. TEM images showed a core-shell structure. Release values of 21.66, 27.75, 43.88 and 16.12% of saffron extract were observed in saliva, hot water, gastric and intestinal media, respectively. Mechanism of safranal release from fibers for saliva, water, gastric and intestinal were well demonstrated by Kopcha, Peppas-Sahlin, Peppas-Sahlin and Ritger-Peppas models, respectively. Finally, the results of this research indicated that produced thermostable core-shell nanofibers can be used in various food industries such as chewing gum and tea bag development.

Basil seed mucilage as a new source for electrospinning: Production and physicochemical characterization.

In this study nanofibers were prepared via the electrospinning technique by basil seed mucilage (BSM) as a new source of hydrocolloid. Polyvinyl alcohol (PVA) was used as an aiding agent. Viscosity and electrical conductivity of BSM/PVA solutions of different volume ratios (100:0, 80:20, 60:40, 40:60, 20:80 and 0:100) were in the range of 790-1300cP and 745-2140µS/cm, respectively. Morphology of nanofibers were investigated using scanning electron microscopy (SEM) that showed an average diameter range of 179-390nm. Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) studies were used to analysis chemical composition, crystalline structure and thermal characteristics of nanofibers. The characteristic picks of basis seed mucilage were found in BSM/PVA nanofibers. The crystalline index of BSM, PVA and BSM/PVA nanofibers were 54, 35 and 43%, respectively. The BSM based nanofibers can be used for different applications such as bioactive encapsulation and packaging film production.