Improving the functional characteristics of thymol-loaded pullulan and whey protein isolate-based electrospun nanofiber

Abstract

The encapsulation of thymol blends was examined for two distinct food polymers, pullulan and whey protein isolate at a concentration of 80:20 (PUL:WPI w/w) through coaxial electrospinning. Scanning electron microscopy (SEM) presented clear illustrations of successful thymol encapsulation in nanofibers with bead-like structures and increased diameter as compared to nanofibers without thymol. The maximum encapsulation efficiency (87.05 ± 1.18%) and loading capacity (17.41 ± 0.24%) of thymol (2%) in (80:20) PUL:WPI nanofibers (THY-WP-NF) have been achieved. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) peaks indicated the presence of thymol within the nanofibers, while X-ray diffraction results demonstrated that the thymol existed in an amorphous state within the nanofibers. Furthermore, the encapsulation process led to an increase in the stability (under light and temperature) of thymol, as well as facilitated targeted release in the small intestine. THY-PW-NF exhibited better in-vitro inhibition activity against alpha-amylase (66.44%), alpha-glucosidase (80.37%) and pancreatic lipase enzymes (65.60%), along with DPPH and ABTS radicals. Conclusively, THY-PW-NF can be utilized in food and pharmaceutical products owing to a large surface area with improved water solubility, antioxidant activity, high-temperature stability and antidiabetic activity of thymol.