Formulation of W/O/W emulsions loaded with short-chain fatty acid and their stability improvement by layer-by-layer deposition using dietary fibers

- W/O/W emulsions loaded with short-chain fatty acid were produced.
- Primary W/O/W emulsions with a highly negative ζ-potential were obtained.
- Surface charge of W/O/W emulsion droplets was controlled by the most outer layer.
- Physical stability of W/O/W emulsion improved after layer-by-layer deposition.

This study prepared water-in-oil-in-water (W/O/W) emulsions loaded with short-chain fatty acid (SCFA) and attempts to improve their stability with layer-by-layer deposition using dietary fibers. The water-in-oil (W/O) emulsion consisted of an inner water phase containing 5 wt% butyric acid and soybean oil phase containing a hydrophobic emulsifier. The weight fraction of the inner water phase was 5 wt%. W/O emulsions with a Sauter mean droplet diameter (d3,2) of 0.4 μm were prepared using high-pressure homogenization. The W/O/W emulsion consisted of W/O emulsion dispersed in an outer water phase containing 0.5 wt% modified lecithin, and the weight fraction of the W/O phase was 20 wt%. The W/O phase was dispersed in the modified lecithin solution to prepare a W/O/W emulsion using rotor-stator homogenization. The d3,2 of the resultant W/O/W emulsion droplets was 16.9 μm, and their ζ-potential was −77.8 mV at pH 5. W/O/W emulsion droplets were coated with chitosan (CHI) and carboxymethyl cellulose (CMC), which is driven by electrostatic interaction. The ζ-potential data indicated successful coating of the droplets. W/O/W emulsion droplets coated with dietary fibers were highly stable over 4 weeks. Our results demonstrated that W/O/W emulsions loaded with SCFA could be better stabilized with layer-by-layer coating using dietary fibers.