Fabrication and characterization of costmary essential oil loaded salep-polyvinyl alcohol fast-dissolving electrospun nanofibrous mats

The aim of this study was to fabricate fast-dissolving costmary essential oil (CEO) loaded salep electrospun nanofibrous mat to improve its utility as flavoring and bioactive compound in food application. For this purpose, first, salep (0.3% w/v) and polyvinyl alcohol (PVA, 10% w/v) solutions were mixed to obtain different ratios (0:100-100:0 v/v). Salep-PVA solution at ratio of 40:60 v/v presented appropriate solution properties to allow nanofibrous mat fabrication with appropriate morphological structure and the lowest diameter (139.69 nm). Second, different concentrations of CEO (0.5-5% w/v) were incorporated into the best blend solution. The lowest diameter of CEO-loaded salep-PVA nanofibers was obtained at 0.5-1% CEO concentration ranging from 218.30 to 222.43 nm with considerable encapsulation efficiency (93.21-96.62%) and loading capacity (14.71-30.49%). Physicochemical properties of nanofibrous mats were evaluated via Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry analyses. Antioxidant activity of salep-PVA nanofibers was 7.2% while a considerable increase up to 26.88% was observed by CEO addition. The salep-PVA-CEO nanofibrous mats were more hydrophobic due to their highest water contact angle (> 53.84 degrees). The generated nanofibrous mats could be dissolved in the aqueous, acidic, alkaline and oily medium within 480 to 2400 s depending on the type of simulated food medium. The release profiles of CEO fitted well to Peppas-Sahlin with dominant Fickian diffusion mechanism. Taken together, these findings suggest that the designed structure has capacity to give a burst release to the flavoring agents with potential applications in food industry.