Curcumin-encapsulated hydrophilic gelatin nanoparticle to stabilize fish oil-loaded Pickering emulsion

•Curcumin-loaded hydrophilic gelatin nanoparticle was prepared by pH-cycle method.•Particle sizes at different pH were: pH 7.0 > pH 3.0 > pH 5.0 > pH 9.0 > pH 11.0.•It had a high encapsulation efficiency (93.9 ± 0.5 %) and loading capacity (9.4 ± 0.1 %)•Nanoparticle had higher emulsifying activity index (25.1 ± 0.9 m2/g) than gelatin.•Droplet sizes and creaming index of the Pickering emulsions were dependent on pH. Herein, pH-cycle method was explored to prepare curcumin-encapsulated hydrophilic bovine bone gelatin (BBG/Cur) nanoparticle and then the obtained nanoparticle was applied to stabilize fish oil-loaded Pickering emulsion. The nanoparticle had a high encapsulation efficiency (93.9 ± 0.5 %) and loading capacity (9.4 ± 0.1 %) for curcumin. The nanoparticle-stabilized emulsion had higher emulsifying activity index (25.1 ± 0.9 m2/g) and lower emulsifying stability index (161.5 ± 18.8 min) than BBG-stabilized emulsion. The pH affected the initial droplet sizes and creaming index values of the Pickering emulsions: pH 11.0