Potential use of electrospinning process for nano-encapsulation of grape seed extract with different materials

Grape seeds are rich in phenolic and antioxidant compounds, and grape seed extract (GSE) can be nano-encapsulated so that its bioavailability and stability can be improved. In this thesis, different polymers (PVA, bovine gelatin, corn starch and beta-CD) were used to nano-encapsulate freeze-dried GSEs by electrospinning process. SEM images were obtained for the characterization of encapsulated Burdur Dimrit (Vitis vinifera) GSE. The total phenolic and antioxidant activity of GSE (in polymer solution) were determined before and after nano-encapsulation. The structural characterization of nano-encapsulated GSE was determined using FTIR, DSC and XRD analyzes. It was not appropriate to use corn starch in nano-encapsulation of GSE by electrospin process, and electrical conductivity values of polymeric mixtures were between 34.03-198.90uS/cm while the diameter of encapsulated Burdur Dimrit GSE with different polymers ranged from 0.17 to 0.18 um. PVA was the best to preserve the total phenolic content and antioxidant activity (ABTS method) for the nano-encapsulation of GSE with different polymers. According to XRD results, amorphous GSE had a tendency towards crystal structure following nano-encapsulation, and the FTIR spectra revealed that GSE preserved its functional groups during nano-encapsulation with different polymers. While the DSC spectra of the GSE after nano-encapsulation differed, the DSC spectra of both GSEs encapsulated with the same polymer were similar, and the encapsulated GSE had an endothermic heat flow. Results indicated that electrospinning has a potential to be used in the nano-encapsulation of GSEs with different polymers, and this new nano-encapsulated product of GSE can be used as a raw material in the food industry or a food additive for the enrichment of foods.