Nanofiber encapsulation of tomato peels extract using electrospinning to develop their efficiency and stability

In this study, it was aimed to encapsulate the carotenoids, which had been extracted from tomato peels, into zein and gelatin polymers by electrospinning technique. Firstly, the process parameters of electrospinning were optimized for each polymer to obtain the thinnest and homogeneously distributed fibers by electrospinning process. Secondly, the tomato peel extract (TPE) was encapsulated into gelatin and zein fibers by using these optimum conditions. According to DSC results, thermal stability of the extract was improved by nanoencapsulation. FTIR spectra showed that the TPE could be compatibly entrapped into the electrospun fibers. Compared to non-encapsulated extract, the encapsulated one had better retention of lycopene and antioxidant activity during 14-days storage under all tested conditions. Moreover, antioxidant activity of the extract increased about 10-fold by nanoencapsulation. More interestingly, the solubility of TPE in water was highly enhanced when it was encapsulated into gelatin nanofibers. Thirdly, the encapsulated TPE within gelatin and zein nanofibers applied in yogurt as a model food to investigate their effect on the antioxidant and physicochemical properties of yogurt during storage at 4°C. The yogurt samples enriched with TPE had closer characteristics to control sample in terms of pH, acidity, syneresis, and viscosity parameters. The incorporation of TPE-loaded fibers resulted in increasing of the free radical scavenging activity of yogurt by 40-60%. The yogurts enriched with TPE-loaded fibers were redder, darker, and more yellow than control yogurt. Overall, it was realized that nanoencapsulation by electrospinning is an effective way to stabilize carotenoids and improve their functional properties and it is promising to use them in food processing. However, future toxicological studies are needed to establish the potential adverse effects of nanotechnology on human health and environment.