Development of postbiotic-loaded nanofibers by Pickering emulsion electrospinning: physicochemical characterization and biofunctional potential

Postbiotic compounds offer advantages over viable probiotics because of their greater physicochemical stability. However, their incorporation into structured delivery systems that retain their functionality remains challenging. Combining Pickering emulsions with electrospinning may provide an effective approach for incorporating these compounds into functional fibrous matrices, but the effects of formulation variables on emulsion and fiber characteristics remain insufficiently understood. This study investigated the incorporation of postbiotic components derived from Lactobacillus rhamnosus GG using Pickering emulsion electrospinning and evaluated the effects of particle concentration and sunflower oil content on physicochemical and antioxidant properties.

Postbiotic preparations were characterized by high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and Fourier transform infrared (FTIR) spectroscopy. Increasing particle concentration from 5 to 15 g L^-1 reduced emulsion droplet size and creaming while increasing viscosity, encapsulation efficiency, and fiber loading. The smallest fiber diameter (1.10 ± 0.10 μm) was obtained at the highest particle concentration and with the lowest oil content, whereas the largest (1.83 ± 0.15 μm) occurred at the lowest particle concentration and highest oil content. Encapsulation efficiency ranged from 62.33 ± 2.52% to 91.00 ± 1.00%. Antioxidant responses varied among assays. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity increased with both particle concentration and oil content, reaching a maximum mean value of 51.33%, whereas ferric reducing antioxidant power (FRAP) increased with particle concentration but decreased with increasing sunflower oil content. Fourier transform infrared spectra also indicated molecular associations among the components of the electrospun system.

The particle-to-oil balance is a key determinant of emulsion behavior, encapsulation performance, antioxidant response, and fiber characteristics. Combining postbiotic-derived components with Pickering emulsion electrospinning therefore represents a promising strategy for developing functional delivery systems for food-related applications. © 2026 Society of Chemical Industry.