Nanoencapsulation of carotenoids extracted from tomato peels into zein fibers by electrospinning

BACKGROUND: The processing of tomatoes generates significant amounts of tomato waste, which has a high potential to be used in food industry as a natural food colorant, antioxidant, and food supplement providing health benefits. However, it is difficult to incorporate the carotenoids into different food formulations because they are relatively unstable in food systems. Hence, this novel study investigated the use of an electrospinning technique for the encapsulation of carotenoids extracted from tomato peel into zein nanofibers to improve its thermal and storage stability, and antioxidant activity. RESULTS: Composite zein nanofibers containing the carotenoids extracted from tomato peel (TP) were successfully produced with above 90% encapsulation efficiency by electrospinning. Scanning electron microscope (SEM) analysis revealed that the extract-loaded fibers exhibited morphology similar to the neat zein fibers with a bead-free, smooth, and homogeneously-distributed morphology. Differential scanning calorimetry (DSC) thermograms showed that the thermal stability of the extract was enhanced by nanoencapsulation. No significant changes in the Fourier transform infrared (FTIR) spectra of extract-loaded zein fibers were observed compared to neat zein fiber, showing that the TP extract could be entrapped into the zein fibers. Compared to non-encapsulated extract, the encapsulated one inside zein fibers had better retention of lycopene and antioxidant activity (AA) during 14-days' storage. More interestingly, the AA of the extract increased about 11-fold by nanoencapsulation. CONCLUSION: This study showed that nanoencapsulation by electrospinning is an effective way to stabilize carotenoids, which is promising for their use in food processing. © 2018 Society of Chemical Industry.