Edible gelatin-based nanofibres loaded with oil encapsulating high-oleic palm oil emulsions

Abstract

Gelatin-based nanofibres (NF) incorporating a high-oleic palm oil (HOPO) nanoemulsion or macroemulsion were electrospun. An I-optimal response surface design was used for studying the effect of gelatin mass fraction, tip-collector distance and emulsion type (factors) on fibre diameter (Df). The NF had a Df ranging from 136.9 to 240.8 nm and no beads; synergic effects between factors were observed as significant over Df. Furthermore, topography, roughness, oil distribution, peroxide value (PV), antioxidant activity (AOX), thermal stability and crystallinity of two optimised NF were analysed; smooth and slightly rugose NF were observed by atomic force microscopy (AFM) and heterogeneously distributed oil by confocal laser scanning microscopy (CLSM). Microfluidisation and electrospinning had low PV, high encapsulation efficiency (>94 %) and high AA values, i.e., efficient encapsulation processes. NF thermal stability was affected by emulsion type; a more amorphous structure tended to give higher droplet size inside fibres. Despite Df was not affected by emulsion droplet size, NF's physico-chemical properties showed changes.