Preparation of food-grade EDC/NHS-crosslinked gelatin nanoparticles and their application for Pickering emulsion stabilization

Herein, a safe desolvation and crosslinking method was developed to prepare food-grade bovine bone gelatin (BBG) nanoparticles for Pickering emulsion stabilization. The nanoparticle-like structures were formed by adjusting pH 9.0 and adding ethanol, and then stable nanoparticles were formed by using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) as crosslinker. Compared with other pH (2.5, 5.0, 7.0, and 12.0), pH 9.0 was the appropriate pH to prepare BBG nanoparticles. Individual nanoparticles (6.50 nm in height), oligomeric nanoparticles (13.42-22.52 nm in height), and polymeric nanoparticles (obvious liquid-precipitate separation) were formed at EDC·HCl/NHS concentrations of 6, 9-12, and 15-20 mg/mL, respectively. The oligomeric nanoparticles induced the highest emulsion creaming stability. The emulsion creaming ability increased with the increase of BBG nanoparticle concentrations. Low NaCl concentration (e.g., 100 mmol/L) could increase the emulsion creaming stability. Finally, 4 °C was the best storage temperature for fish oil-loaded Pickering emulsions.