Electrospun Gelatin/Dextran Nanofibers from W/W Emulsions: Improving Probiotic Stability Under Thermal and Gastrointestinal Stress

Abstract

Probiotics offer numerous health benefits; however, preserving their viability during processing and storage remains a major challenge. This study investigates the electrospinning of gelatin/dextran (GE/DEX) water-in-water (W/W) emulsions for Lactobacillus plantarum encapsulation. By varying dextran concentrations, the ways in which phase behavior, viscosity, and conductivity influence fiber formation and morphology were analyzed. Scanning and transmission electron microscopy confirmed core–shell nanofibers, while FT-IR revealed electrostatic interactions rather than chemical reactions between GE and DEX. Encapsulated probiotics exhibited enhanced viability under thermal stress (65 and 72 °C), storage (25 and 4 °C), and simulated gastrointestinal conditions, maintaining high viability (>8 log CFU/g) compared with free cells. Notably, gelatin-rich shell phases provided stronger protection, likely due to gelation properties restricting bacterial mobility. These findings demonstrate that electrospinning of W/W emulsions is an effective strategy to improve probiotic stability, offering potential applications in functional foods.

Keywords

• water-in-water emulsion
• electrospinning
• probiotic encapsulation
• viability